The 100 most-cited articles in Advanced Functional Materials, 2021

Abstract Rational manipulation of hollow structure with uniform heterojunctions is evolving as an effective approach to meet the lightweight and high‐performance microwave absorption for metal‐organic frameworks (MOFs) derived absorbers. Herein, a new and controlled synergistic protecting‐etching strategy is proposed to construct shelled ZIF‐67 rhombic dodecahedral cages using tannic acid under theoretical guidance, then hollow Co@N‐doped carbon nanocages with uniform heterojunctions and hierarchical micro‐meso‐macropores are obtained via a pyrolysis process, which addresses the shortcomings of using sacrificing templates or corrosive agents. The outer Co@N‐doped carbon shell, composed of highly dispersive core‐shell heterojunctions, possesses micro‐mesopores while the inner hollow macroporous cavity endows the absorbers with lightweight characteristics. Accordingly, the maximum reflection loss is −60.6 dB at 2.4 mm and the absorption bandwidth reaches 5.1 GHz at 1.9 mm with 10 wt% filler loading, exhibiting superior specific reflection loss compared with the vast majority of…

Abstract Bone tissue engineering (BTE) is a rapidly growing field aiming to create a biofunctional tissue that can integrate and degrade in vivo to treat diseased or damaged tissue. It has become evident that scaffold fabrication techniques are very important in dictating the final structural, mechanical properties, and biological response of the implanted biomaterials. A comprehensive review of the current accomplishments on scaffold fabrication techniques, their structure, and function properties for BTE is provided herein. Different types of biomaterials ranging from inorganic biomaterials to natural and synthetic polymers and related composites for scaffold processing are presented. Emergent scaffolding techniques such as electrospinning, freeze‐drying, bioprinting, and decellularization are also discussed. Strategies to improve vascularization potential and immunomodulation, which is considered a grand challenge in BTE scaffolding, are also presented.

Abstract Closing the carbon‐, hydrogen‐, and nitrogen cycle with renewable electricity holds promises for the mitigation of the facing environment and energy crisis, along with the continuing prosperity of the human society. Descriptors bridge the gap between the physicochemical factors of electrocatalysts and their boosted activity and serve as guiding principles during the rational design of electrocatalysts. The optimal adsorption strength of key intermediates is potentially accessed under the tendentious guidelines proposed by indicators, such as d‐band center, Δ G H , E O* , coordination number (CN), bond length, etc. Here, in this review, a comprehensive summary of the recent advances achieved regarding the descriptors during the rational design of electrocatalysts that aims for the recycling of C/H/N‐containing chemicals is offered. The review is initiated by providing the necessity of the development of efficient electrocatalysts and then the physics behind the d‐band center is introduced. Then a summary of the recent progress relating to the development of electrocatalysts…

Abstract Inspired by the ultralight and structurally robust spider webs, flexible nanofibril‐assembled aerogels with intriguing attributes have been designed for achieving promising performances in various applications. Here, conductive polyimide nanofiber (PINF)/MXene composite aerogel with typical “layer‐strut” bracing hierarchical nanofibrous cellular structure has been developed via the freeze‐drying and thermal imidization process. Benefiting from the porous architecture and robust bonding between PINF and MXene, the PINF/MXene composite aerogel exhibits an ultralow density (9.98 mg cm−3), intriguing temperature tolerance from ‐50 to 250 °C, superior compressibility and recoverability (up to 90% strain), and excellent fatigue resistance over 1000 cycles. The composite aerogel can be used as a piezoresistive sensor, with an outstanding sensing capacity up to 90% strain (corresponding 85.21 kPa), ultralow detection limit of 0.5% strain (corresponding 0.01 kPa), robust fatigue resistance over 1000 cycles, excellent piezoresistive stability and reproductivity in extremely harsh…

Abstract A new type of lanthanum‐based high entropy perovskite oxide (HEPO) electrocatalyst for the oxygen evolution reaction is reported. The B‐site lattices in the HEPO consist of five consecutive first‐row transition metals, including Cr, Mn, Fe, Co, and Ni. Equimolar and five non‐equimolar HEPO electrocatalysts are studied for their OER electrocatalytic performance. In the five non‐equimolar HEPOs, the concentration of one of the five transition metals is doubled in individual samples. The performances of all the HEPOs outperform the single perovskite oxides. The optimized La(CrMnFeCo 2 Ni)O 3 HEPO exhibits an outstanding OER overpotential of 325 mV at a current density of 10 mA cm −2 and excellent electrochemical stability after 50 h of testing.

Abstract Semiconductor photocatalysis acts as a sustainable green technology to convert solar energy for environmental purification and production of renewable energy. However, the current photocatalysts suffer from inefficient photoabsorption, rapid recombination of photogenerated electrons and holes, and inadequate surface reactive sites. Introduction of oxygen vacancies (OVs) in photocatalysts has been demonstrated to be an efficacious strategy to solve these issues and improve photocatalytic efficiency. This review systematically summarizes the recent progress in the oxygen vacant semiconductor photocatalysts. Firstly, the formation and characterizations of OVs in semiconductor photocatalysts are briefly introduced. Then, highlighted are the roles of OVs in the photocatalytic reactions of three types of typical oxygen‐containing semiconductors, including metal oxides (TiO 2 , ZnO, WO 3 , W 18 O 49 , MoO 3 , BiO 2‐x , SnO 2 , etc), hydroxides (In(OH) 3 , Ln(OH) 3 (Ln=La, Pr, and Nd), Layered double hydroxides) and oxysalts (bismuth‐based oxysalts and others) photocatalysts.…

Abstract Triboelectric nanogenerators (TENGs) represent an emerging technology in energy harvesting, medical treatment, and information technology. Flexible, portable, and self‐powered electronic devices based on TENGs are much desired, whereas the complex preparation processes and high cost of traditional flexible electrodes hinder their practical applications. Here, an MXene/polyvinyl alcohol (PVA) hydrogel TENG (MH‐TENG) is presented with simple fabrication, high output performance, and versatile applications. The doping of MXene nanosheets promotes the crosslinking of the PVA hydrogel and improves the stretchability of the composite hydrogel. The MXene nanosheets also form microchannels on surfaces, which not only enhances the conductivity of the hydrogel by improving the transport of ions but also generates an extra triboelectric output via a streaming vibration potential mechanism. The measured open‐circuit voltage of the MH‐TENG reaches up to 230 V even in a single‐electrode mode. The MH‐TENG can be stretched up to 200% of the original length and demonstrates a monotonical…

Abstract Solid‐state lithium (Li) metal batteries (SSLMBs) have become a research hotspot in the energy storage field due to the much‐enhanced safety and high energy density. However, the SSLMBs suffer from failures including dendrite‐induced short circuits and contact‐loss‐induced high impedance, which are highly related to the Li plating/stripping kinetics and hinder the practical application of SSLMBs. The maximum endurable current density of lithium battery cycling without cell failure in SSLMB is generally defined as critical current density (CCD). Therefore, CCD is an important parameter for the application of SSLMBs, which can help to determine the rate‐determining steps of Li kinetics in solid‐state batteries. Herein, the theoretical and practical meanings for CCD from the fundamental thermodynamic and kinetic principles, failure mechanisms, CCD identifications, and influence factors for improving CCD performances are systematically reviewed. Based on these fundamental understandings, a series of strategies and outlooks for future researches on SSLMB are presented,…

Abstract In recent decades, flexible and wearable devices have been extensively investigated due to their promising applications in portable mobile electronics and human motion monitoring. MXene, a novel growing family of 2D nanomaterials, demonstrates superiorities such as outstanding electrical conductivity, abundant terminal groups, unique layered‐structure, large surface area, and hydrophilicity, making it to be a potential candidate material for flexible and wearable devices. Numerous pioneering works are devoted to develop flexible MXene‐based composites with various functions and designed structures. Therefore, the latest progress of the flexible MXene‐based composites for wearable devices is summarized in this review, focusing on the preparation strategies, working mechanisms, performances, and applications in sensors, supercapacitors, and electromagnetic interference shielding materials. Moreover, the current challenges and future outlooks are also discussed.

Abstract Photocatalysis is considered to be a green and environment‐friendly technology since it can convert solar energy into other types of chemical energies. Over the past several years, metal‐organic frameworks (MOFs)‐based photocatalysts have received remarkable research interest due to their unique morphology, high photocatalytic performance, good chemical stability, easy synthesis, and low cost. In this review, the synthetic strategies of developing MOFs‐based photocatalysts are first introduced. Second, the recent progress in the fabrication of various types of MOFs composites photocatalysts is summarized. Third, the different applications including hydrogen evolution reaction, oxygen evolution reaction, overall water splitting, nitrogen reduction reaction, carbon dioxide reduction reaction as well as photodegradation of organic pollutants of MOFs‐based photocatalysts are summed up. Finally, the challenges and some suggestions for the future development of MOFs‐ and their composites‐based photocatalysts are also highlighted. It is expected that this report will help…

Abstract The manufacture of bionic materials to simulate the natural counterparts has attracted extensive attention. As one of the subcategories of biomimetic materials, the development of artificial enzyme is intensive pursuing. As a kind of artificial enzyme, nanozymes are dedicated to solve the limitations of natural enzymes. In recent years, attributed to the explosive development of nanotechnology, biotechnology, catalysis science, computational design and theory calculation, research on nanozymes has made great progress. To highlight these achievements and help researchers to understand the current investigation status of nanozyme, the state‐of‐the‐art development in nanozymes from fabrication materials to bioapplications are summarized. First different raw materials are summarized, including metal‐based, metal‐free, metal‐organic frameworks‐based, and some other novel matters, which are applied to fabricate nanozymes. The different types of enzymes‐like catalytic activities of nanozymes are briefly discussed. Subsequently, the wide applications of nanozymes such as…

Abstract Bone related diseases have caused serious threats to human health owing to their complexity and specificity. Fortunately, owing to the unique 3D network structure with high aqueous content and functional properties, emerging hydrogels are regarded as one of the most promising candidates for bone tissue engineering, such as repairing cartilage injury, skull defect, and arthritis. Herein, various design strategies and synthesis methods (e.g., 3D‐printing technology and nanoparticle composite strategy) are introduced to prepare implanted hydrogel scaffolds with tunable mechanical strength, favorable biocompatibility, and excellent bioactivity for applying in bone regeneration. Injectable hydrogels based on biocompatible materials (e.g., collagen, hyaluronic acid, chitosan, polyethylene glycol, etc.) possess many advantages in minimally invasive surgery, including adjustable physicochemical properties, filling irregular shapes of defect sites, and on‐demand release drugs or growth factors in response to different stimuli (e.g., pH, temperature, redox, enzyme, light, magnetic,…

Abstract Cs 2 AgBiBr 6 , as a benchmark lead‐free double perovskite, has emerged as a promising alternative to lead‐based perovskites because of its high stability, non‐toxicity, exceptional optoelectronic properties, and multifunctionality. To encourage further research on Cs 2 AgBiBr 6 and its broad applications, in this review, its fundamental properties including the structure‐property relation, synthesis, stability, origin of absorption and photoluminescence, electron‐phonon coupling, role of defects, charge carrier dynamics, and bandgap modulation are comprehensively emphasized. The recent progress on the wide applications including solar cells, light/X‐ray detectors, and ferroelectric/magnetic devices are highlighted. Moreover, the challenges of Cs 2 AgBiBr 6 materials and related applications are discussed and perspectives are provided for guiding the future development of this research area.

Abstract Current treatments for chronic diabetic wounds remain unsatisfactory due to the lack of ideal wound dressings that can integrate matching mechanical strength, fast self‐healability, facile dressing change, and multiple therapeutic effects into one system. In this work, benefiting from the catechol groups and therapeutic effect of epigallocatechin‐3‐gallate (EGCG, green tea derivative), a smart hydrogel dressing can be conveniently obtained through copolymerization of the complex formed by EGCG and 3‐acrylamido phenylboronic acid (APBA) (the formation of boronate ester bond) and acrylamide. The resulting hydrogel features adequate mechanical properties, self‐healing capability, and tissue adhesiveness. Otherwise, the substantial release of EGCG can not only realize anti‐oxidation, antibacterial, anti‐inflammatory and proangiogenic effect, and modulation of macrophage polarization to accelerate wound healing, but also facilitate easy dressing change. This advanced hydrogel provides a facile and effective way for diabetic chronic wound management and may be extended for the…

Abstract High‐entropy alloys (HEAs) have attracted widespread attention in electrocatalysis due to their unique advantages (adjustable composition, complex surface, high tolerance, etc.). They allow for the formation of new and tailorable active sites in multiple elements adjacent to each other, and the interaction can be tailored by rational selection of element configuration and composition. However, it needs to be further explored in catalyst design, the interaction of elements, and the determination of active sites. This review article focuses on the important progress for multi‐sites electrocatalysis in HEAs. The classification is done on the basis of catalytic reaction, including hydrogen evolution reaction, oxygen evolution reaction, oxygen reduction reaction, alcohol oxidation reaction, carbon dioxide reduction reaction, and nitrogen reduction reaction. Based on experiments and theories, a more in‐depth exploration of the high catalytic activity of HEAs will be conducted, including the selection of elements (the special role of each element in catalysis) and the multi‐sites…

Abstract The cycle life of aqueous zinc‐ion batteries (ZIBs) is limited by the notable challenges of cathode dissolution, water reactivity, and zinc dendrites. Here, it is demonstrated that by tuning the electrolyte solvation structure, the issues for both the electrodes and the electrolyte can be addressed simultaneously. Specifically, a fire‐retardant triethyl phosphate (TEP) is demonstrated as a cosolvent with strong solvating ability in a nonaqueous/aqueous hybrid electrolyte. The TEP features a higher donor number (26 kcal mol−1) than H2O (18 kcal mol−1), preferring to form a TEP occupied inner solvation sheath around Zn2+ and strong hydrogen bonding with H2O. The TEP coordinated electrolyte structure can inhibit the reactivity of H2O with V2O5 and leads to a robust polymeric‐inorganic interphase (poly‐ZnP2O6 and ZnF2) on zinc anode effectively preventing the dendrite growth and parasitic water reaction. With such an optimized electrolyte, the Zn/Cu cells perform high average Coulombic efficiency of 99.5%, and the full cell with a low capacity ratio of Zn:V2O5 (2:1) and lean…

Abstract Metal–organic frameworks (MOFs) and their derivatives, featuring unique 3D microstructures and enhanced electromagnetic properties, are illuminating infinite possibilities for electromagnetic functional materials and devices, receiving significant attention from domestic and foreign researchers. Herein, the design strategy of the MOF monomer is investigated, and the electromagnetic response mechanism is systematically analyzed. Research is emphatically introduced regarding MOF‐based materials in microwave absorption and electromagnetic interference shielding. Finally, a clear insight on the quickly growing field is given, and the current challenges and future research directions are summarized and predicted.

Abstract Graphitic carbon nitride (g‐C 3 N 4 ) have attracted great attention in the field of energy conversion and storage due to its unique layered structure, tunable bandgap, metal‐free characteristic, high physicochemical stability, and easy accessibility. 2D g‐C 3 N 4 nanosheets have the features of short charge/mass transfer path, abundant reactive sites and easy functionalization, which are beneficial to optimizing their performance in different fields. However, the reviews of the comprehensive applications of 2D g‐C 3 N 4 for energy conversion and storage are rare. Herein, this review first introduces the physicochemical properties of bulk g‐C 3 N 4 and g‐C 3 N 4 nanosheets, and then summarizes the synthetic strategies of 2D g‐C 3 N 4 nanosheets in detail, such as thermal oxidation etching, chemical exfoliation, ultrasonication‐assisted liquid phase exfoliation, chemical vapor deposition, and others. Emphasis is focused on the rational design and development of 2D g‐C 3 N 4 nanosheets for the diversified applications in energy conversion and storage, including photocatalytic…

Abstract The pursuit of sustainable energy utilization arouses increasing interest in efficiently producing durable battery materials and catalysts with minimum environmental impact. As green, safe, and cheap eutectic mixtures, deep eutectic solvents (DESs) provide tremendous opportunities and open up attractive perspectives as charge transfer and reaction media for electrochemical energy storage and conversion (EESC). In this review, the fundamental properties of DESs are first summarized. Then, the important roles that DESs play in various EESC technologies including advanced electrolytes for batteries/supercapacitors, media for the preparation of electrode materials and catalysts, and extracting agents for battery recycling are systematically reviewed. A particular focus is placed on the fundamental understanding of structure–composition–property–performance relationships. Finally, the challenges for the controllable design of DESs for EESC applications and future developments are presented. This review is expected to shed light on developing advanced DESs for next‐generation…

Abstract Diabetic wound healing still faces great challenges due to the excessive inflammation, easy infection, and impaired angiogenesis in wound beds. The immunoregulation of macrophages polarization toward M2 phenotype that facilitates the transition from inflammation to proliferation phase has been proved to be an effective way to improve diabetic wound healing. Herein, an M2 phenotype‐enabled anti‐inflammatory, antioxidant, and antibacterial conductive hydrogel scaffolds (GDFE) for producing rapid angiogenesis and diabetic wound repair are reported. The GDFE scaffolds are fabricated facilely through the dynamic crosslinking between polypeptide and polydopamine and graphene oxide. The GDFE scaffolds possess thermosensitivity, self‐healing behavior, injectability, broad‐spectrum antibacterial activity, antioxidant and anti‐inflammatory ability, and electronic conductivity. GDFE effectively activates the polarization of macrophages toward M2 phenotype and significantly promotes the proliferation of dermal fibroblasts, the migration, and in vitro angiogenesis of endothelial cells…

Abstract The demands for green production of hydrogen peroxide have triggered extensive studies in the photocatalytic synthesis, but most photocatalysts suffer from rapid charge recombination and poor 2e − oxygen reduction reaction (ORR) selectivity. Here, a novel composite photocatalyst of cyano‐rich graphitic carbon nitride g‐C 3 N 4 is fabricated in a facile manner by sodium chloride‐assisted calcination on dicyandiamide. The obtained photocatalysts exhibit superior activity (7.01 m m h −1 under λ ≥ 420 nm, 16.05 m m h −1 under simulated sun conditions) for H 2 O 2 production and 93% selectivity for 2e − ORR, much higher than that of the state‐of‐the‐art photocatalyst. The porous g‐C 3 N 4 with Na dopants and cyano groups simultaneously optimize two limiting steps of the photocatalytic 2e − ORR: photoactivity, and selectivity. The cyano groups can adjust the band structure of g‐C 3 N 4 to achieve high activity. They also serve as oxygen adsorption sites, in which local charge polarization facilitates O 2 adsorption and protonation. With the aid of Na + , the O 2 is reduced to…

Abstract Triggered by the endogenous chemical energy in the tumor microenvironment (TME), chemodynamic therapy (CDT) as an emerging non‐exogenous stimulant therapeutic modality has received increasing attention in recent years. The chemodynamic agents can convert internal hydrogen peroxide (H 2 O 2 ) into the lethal reactive oxygen species (ROS) hydroxyl radicals ( • OH) for oncotherapy. Compared with other therapeutic modalities, CDT possesses many notable advantages, such as tumor‐specific, highly selective, fewer systemic side effects, and no need for external stimulation. Nevertheless, mild acid pH, low H 2 O 2 content, and overexpressed reducing substance in TME severely suppressed the CDT efficiency. With the rapid development of nanotechnology, some kinds of nanomaterials have been utilized with improved CDT efficiency. In particular, the excellent photo‐, ultrasound‐, magnetic‐, and other stimuli‐response properties of nanomaterials make it possible for combination cancer therapy of CDT with other therapeutic modalities, and it has shown superior anti‐cancer activity than…

Abstract Conductive hydrogels as flexible electronic devices, not only have unique attractions but also meet the basic need of mechanical flexibility and intelligent sensing. How to endow anisotropy and a wide application temperature range for traditional homogeneous conductive hydrogels and flexible sensors is still a challenge. Herein, a directional freezing method is used to prepare anisotropic MXene conductive hydrogels that are inspired by ordered structures of muscles. Due to the anisotropy of MXene conductive hydrogels, the mechanical properties and electrical conductivity are enhanced in specific directions. The hydrogels have a wide temperature resistance range of −36 to 25 °C through solvent substitution. Thus, the muscle‐inspired MXene conductive hydrogels with anisotropy and low‐temperature resistance can be used as wearable flexible sensors. The sensing signals are further displayed on the mobile phone as images through wireless technology, and images will change with the collected signals to achieve motion detection. Multiple flexible sensors are also assembled into a…

Abstract Interfacial solar steam generation offers a promising and cost‐effective way for saline water desalination. However, salt accumulation and deposition on photothermal materials during saline and brine evaporation is detrimental to the stability and sustainability of solar evaporation. Although several antisalt strategies are developed, it is difficult to simultaneously achieve high evaporation rates ( > 2.0 kg m −2 h −1 ) and energy efficiencies. In this study, a self‐rotating photothermal evaporator with dual evaporation zones (i.e., high‐temperature and low‐temperature evaporation zones) is developed. This photothermal evaporator is sensitive to weight imbalance ( < 15 mg) thus is able to quickly respond to salt accumulation by rotation to refresh the evaporation surface, while the dual evaporation zones optimize the energy nexus during solar evaporation, simultaneously realizing excellent salt‐resistant performance and high evaporation rate (2.6 kg m −2 h −1 ), which can significantly contribute to the real‐world application of solar steam generation technology.

Abstract To couple hydrogen evolution reaction (HER) with urea oxidation reaction (UOR) is a promising approach to produce H 2 with reduced energy consumption. However, the development of a low‐cost and high‐performance bifunctional electrocatalyst toward HER and UOR is still a challenge. In this work, oxygen‐incorporated nickel molybdenum phosphide nanotube arrays are synthesized on nickel foam (O‐NiMoP/NF) via electrodeposition accompanied with in‐situ template etching. Benefiting from the modulated electronic structure and the nanotube array architecture of O‐NiMoP, the self‐supporting O‐NiMoP/NF electrodes demonstrate highly efficient bifunctional catalytic activity toward HER and UOR. Particularly, in the HER and UOR (HER||UOR) coupled system for H 2 production, a significantly reduced cell voltage of 1.55 V is obtained at the current density of 50 mA cm –2 , which is about 300 mV lower than that of the conventional water electrolysis. Density functional theory calculations reveal that the remarkable HER and UOR activities originated from the Ni sites with the modulated…

Abstract Skin effect and high density are the main reasons that restrict the search of lightweight and high‐performance metal‐based electromagnetic (EM) wave absorbing materials. Although nanostructured metal materials have been fabricated to solve above problems, poor dispersibility and chemical stability issues brought about by high surface energy due to existing nano‐size effect. In this work, lightweight Ni foam with NiO/NiFe 2 O 4 in situ growth composites are fabricated by a facile and universal route as an effective alternative to high‐performance metal‐based EM wave absorber. Impressively, it is found that the foam structure and NiO/NiFe 2 O 4 /Ni components can synergistically boost EM wave absorption capacity. In detail, impedance matching from foam structure and energy dissipation from interfacial polarization and defect induced polarization provided by NiO/NiFe 2 O 4 mainly contributes to its ultra‐broadband EM wave absorption performance. As a result, the as‐prepared sample (0.06 g·cm −3 ) delivers a wide absorption bandwidth of 14.24 GHz and thin thickness of 0.6 mm,…

Abstract Electrochemical water splitting is a critical energy conversion process for producing clean and sustainable hydrogen; this process relies on low‐cost, highly active, and durable oxygen evolution reaction/hydrogen evolution reaction electrocatalysts. Metal cations (including transition metal and noble metal cations), particularly high‐valence metal cations that show high catalytic activity and can serve as the main active sites in electrochemical processes, have received special attention for developing advanced electrocatalysts. In this review, heterogenous electrocatalyst design strategies based on high‐valence metal sites are presented, and associated materials designed for water splitting are summarized. In the discussion, emphasis is given to high‐valence metal sites combined with the modulation of the phase/electronic/defect structure and strategies of performance improvement. Specifically, the importance of using advanced in situ and operando techniques to track the real high‐valence metal‐based active sites during the electrochemical process is highlighted. Remaining…

Abstract Hydrogel‐based wearable electronic devices have received increasing attention. However, the construction of underwater strain sensors remains a significant challenge because of the swelling of hydrogels in an aquatic environment. This work presents the fabrication of an anti‐swellable hydrogel composed of polyvinyl alcohol (PVA), a copolymer of [2‐(methacryloyloxy) ethyl]dimethyl‐(3‐sulfopropyl) ammonium hydroxide (SBMA) and 2‐hydroxyethyl methacrylate. Interestingly, facile switch of the SBMA moiety from neutral to positively charged status at a low pH value leads to reduced osmotic pressure of the hydrogel for electrostatic repulsion‐driven elimination of water molecules and anti‐swelling. The resulting anti‐swellable hydrogel exhibits high toughness (518 kJ m −3 ) and compressive modulus (8.12 Mpa), ionic conductivity (up to 4.58 S m −1 ), and anti‐swelling behavior (equilibrium swelling ratio of 9% in water for 30 days). An underwater strain sensor based on this anti‐swellable hydrogel is further developed to monitor the movements of underwater sports. High sensitivity…

Abstract 2D layered nanomaterials as photocatalysts have attracted much attention in the field of solar hydrogen production due to their unique electronic structure and abundant active sites. Nevertheless, the rational design and interfacial regulation of 2D Z‐scheme heterojunction are still challenging. Herein, an ultrathin 2D ZnIn 2 S 4 /g‐C 3 N 4 Z‐scheme heterojunction is precisely constructed via in‐situ growth of ZnIn 2 S 4 on the g‐C 3 N 4 . By carefully regulating the interface structure in heterojunction, the hydrogen evolution performance can be greatly improved. The optimized photocatalyst exhibits a remarkable photocatalytic activity without Pt as cocatalyst, which is primarily ascribed to the synergistic effect of abundant active sites, enhanced photoresponse, and valid interfacial charge transfer channels. Meanwhile, the spectroscopic analyses and density functional theory (DFT) calculation results comprehensively prove that the promoted interfacial charge separation in 2D Z‐scheme heterojunction is another key factor for the enhanced photocatalytic performance. This…

Abstract Inspired by the human skin, electronic skins (e‐skins) composed of various flexible sensors, such as strain sensor, pressure sensor, shear force sensor, temperature sensor, and humility sensor, and delicate circuits, are emerged to mimic the sensing functions of human skins. In this review, the strategies to realize the versatile functionalities of natural skin‐like e‐skins, including strain‐, pressure‐, shear force‐, temperature‐ and humility‐sensing abilities, as well as self‐healing ability and other functions are summarized. Some representative examples of high‐performance e‐skins and their applications are outlined and discussed. Finally, the outlook of the future of e‐skins is presented.

Abstract Oxygen vacancy (VO) is one of the most common defects in metal oxides (MOs), which endow the MOs with many unique physiochemical properties. Even though VO engineering has been applied in photo(electro)catalysis, there are still significant challenges in the understanding of the formation, structure, and property of VO. The VO can be produced by treating MOs under low oxygen atmosphere or in vacuum ruled by the equilibrium of VO formation, while other types of defects can also be generated simultaneously. Identifying and distinguishing the formation and function of Vo remain highly challenging, thus the scrutiny of defect formation energy and structure of VO is significant in VO research. This review critically revisits the electronic property and structure changes of MOs upon the generation of Vo. It not only provides clues to detect VO, but also specifies the role of VO in a particular material system considering its drastic influence on light harvesting, conductivity, energy level, surface adsorption, and others. The review also presents a perspective on the future…

Abstract Lithium extraction from salt lake brines is highly demanded to circumvent the lithium supply shortage. However, polymer nanofiltration membranes suffer from low lithium permeability while nanofluidic devices are hindered by complicated preparation and miniaturized scales despite high permeability. Here, the authors report a facile strategy to prepare positively charged nanofiltration membranes for ultrapermeable and selective separation of lithium ions from concentrated magnesium/lithium mixtures. A new electrolyte monomer (diaminoethimidazole bromide, DAIB) containing bidentate amine groups is designed to modify pristine polyamide composite membranes. Structure characterizations and simulations show that the DAIB modification brings about nano‐heterogeneity that not only improves surface hydrophilicity, but also reduces water transport resistance through the ≈100 nm thick separation layer. Water permeance of the modified membrane improves fivefold and is coupled with good stability in 200‐h continuous nanofiltration. It exhibits high lithium flux (0.7 mol m−2 h−1) for…

Abstract The next‐generation wearable biosensors with highly biocompatible, stretchable, and robust features are expected to enable the change of the current reactive and disease‐centric healthcare system to a personalized model with a focus on disease prevention and health promotion. Herein, a muscle‐fiber‐inspired nonwoven piezoelectric textile with tunable mechanical properties for wearable physiological monitoring is developed. To mimic the muscle fibers, polydopamine (PDA) is dispersed into the electrospun barium titanate/polyvinylidene fluoride (BTO/PVDF) nanofibers to enhance the interfacial‐adhesion, mechanical strength, and piezoelectric properties. Such improvements are both experimentally observed via mechanical characterization and theoretically verified by the phase‐field simulation. Taking the PDA@BTO/PVDF nanofibers as the building blocks, a nonwoven light‐weight piezoelectric textile is fabricated, which hold an outstanding sensitivity (3.95 V N −1 ) and long‐term stability (<3% decline after 7,400 cycles). The piezoelectric textile demonstrates multiple potential…

Abstract Metal halide perovskites have drawn tremendous attention in optoelectronic applications owing to the rapid development in photovoltaic and light‐emitting diode devices. More recently, these materials are demonstrated as excellent gain media for laser applications due to their large absorption coefficient, low defect density, high charge carrier mobility, long carrier diffusion length, high photoluminescence quantum yield, and low Auger recombination rate. Despite the great progress in laser applications, the development of perovskite lasers is still in its infancy and the realization of electrically pumped lasers has not yet been demonstrated. To accelerate the development of perovskite‐based lasers, it is important to understand the fundamental photophysical characteristics of perovskite gain materials. Here, the structure and gain behavior in various perovskite materials are discussed. Then, the effects of charge carrier dynamics and electron–phonon interaction on population inversion in different types of perovskite materials are analyzed. Further, recent advances in…

Abstract Conductive polymer hydrogels are receiving considerable attention in applications such as soft robots and human‐machine interfaces. Herein, a transparent and highly ionically conductive hydrogel that integrates sensing, UV‐filtering, water‐retaining, and anti‐freezing performances is achieved by the organic combination of tannic acid‐coated hydroxyapatite nanowires (TA@HAP NWs), polyvinyl alcohol (PVA) chains, ethylene glycol (EG), and metal ions. The highly ionic conductivity of the hydrogel enables tensile strain, pressure, and temperature sensing capabilities. In particular, in terms of the hydrogel strain sensors based on ionic conduction, it has high sensitivity (GF = 2.84) within a wide strain range (350%), high linearity ( R 2 = 0.99003), fast response (≈50 ms) and excellent cycle stability. In addition, the incorporated TA@HAP NWs act as a nano‐reinforced filler to improve the mechanical properties and confer a UV‐shielding ability upon the hydrogel due to its size effect and the characteristics of absorbing ultraviolet light waves, which can reflect and absorb…

Abstract Aqueous zinc‐ion batteries (AZIBs) are promising candidates for large‐scale energy storage due to the high safety and cost effectiveness. Yet it is suffered from the obscurely uncontrolled Zn2+ deposition that accumulates together and easily penetrates the separator. Here, a 3D long‐range ordered polyacrylonitrile (PAN) nanofiber separator is designed to overcome this barrier. The N atoms on the surface of separator uniformly distribute the ion flux and guide the cation transport through available N–Zn bonds. Hence, the electric field on the anode is evenly distributed, which helps to guide the nucleation, growth, and deposition of zinc ions. Benefit from this functional group, a Zn symmetric cell with PAN separator shows a long‐term stability and dendrite‐free deposition layer with a preferred (101) crystallographic orientation. Meanwhile, the Zn/NH4V4O10 cells display high specific capacity and excellent long‐term durability of 89.2% capacity retention after 1500 cycles at 10 A g−1. This work demonstrates the design of functional separator provides an effective way to…

Abstract Luminescent metal halide materials with flexible crystallography/electronic structures and tunable emission have demonstrated broad application prospects in the visible light region. However, designing near‐infrared (NIR) light‐emitting metal halides remains a challenge. Here, an enlightening prototype is proposed to explore the high‐efficiency broadband NIR emission in metal halide systems by incorporating Sb 3+ into the Cs 2 ZnCl 4 matrix. Combined experimental analysis and density functional theory calculations reveal a modified self‐trapped excitons model to elaborate the NIR emission. The high photoluminescence quantum yield of 69.9% peaking at 745 nm and large full width at half maximum of 175 nm, along with excellent air/thermal stability, show the unique advantages of lead‐free metal halide Cs 2 ZnCl 4 :Sb 3+ as the NIR light source. The substitution of Cl − by Br − further enables the red‐shift of emission peak from 745 to 823 nm. The NIR light‐emitting diode device based on Cs 2 ZnCl 4 :Sb 3+ demonstrates potential as a non‐visible light source in night vision.…

Abstract Achieving rapid and effective hemostasis on irregularly shaped, non‐compressible visceral, and high‐pressure arterial bleeding wounds remains a critical clinical challenge. Herein, an ultrafast self‐gelling and wet adhesive polyethyleneimine/polyacrylic acid/quaternized chitosan (PEI/PAA/QCS) powder is reported as the hemostatic material and wound dressing. PEI/PAA/QCS powder deposited on bleeding wounds can rapidly absorb a large amount of blood to concentrate coagulation factors. Meanwhile, the powder can form an adhesive hydrogel in situ within 4 s upon hydration to form a pressure‐resistant physical barrier. Furthermore, PEI/PAA/QCS hydrogels can aggregate blood cells and platelets to enhance hemostasis. Depositing PEI/PAA/QCS powder on various bleeding wounds, including at the liver and heart, high‐pressure femoral artery and tail vein of rats, arrests the bleeding around 10 s with no rebleeding after ten minutes. Excellent hemostasis of PEI/PAA/QCS powder is further demonstrated against massive hemorrhage in porcine spleen and liver in vivo, which are non‐compressible…

Abstract With the arrival of the Internet of Things (IoTs) era, there is a growing requirement for systems with many sensor nodes in a variety of fields of applications. The demands for wireless, sustainable and independent operation are becoming more and more important for large‐scale sensor networks and systems. For these purposes, a self‐powered sensory system that can utilize the self‐harvested energy from its surroundings to drive the sensors and directly sense external stimuli has attracted great attention. The invention and rapid development of piezoelectric generators (PENGs), which take Maxwell's displacement current as the driving force, has been pushing forward research on self‐powered active mechanical sensors, electronic skins, and human‐robotic interaction. Here, this review starts with a brief introduction of piezoelectric materials, fabrication, and performance improvement. Then, the energy harvesters used for self‐power systems based on recent progress are reviewed. After that, PENGs applications toward recent self‐powered active sensors are divided into four…

Abstract Photothermal therapy (PTT), which utilizes near‐infrared light‐absorbing agents to ablate tumor, has emerged as a highly promising anticancer strategy and received intensive clinical trials in recent years. Mild‐temperature PTT, which circumvents the limitations of conventional PTT (e.g., thermoresistance and adverse effects), is emerging and shows great potential in the forthcoming clinical applications. However, mild‐temperature PTT without adjuvant therapy is not able to completely eradicate tumors because its therapeutic efficacy is dramatically impaired by its inferior heat intensity. As a result, strategies capable of enhancing the anticancer efficacy of mild‐temperature PTT are urgently necessitated, which mainly rely on on‐demand fabrication of functionalized nanoagents. In this review, the strategies of nanoagent‐promoted mild‐temperature PTT are highlighted. Furthermore, challenges and opportunities in this field are rationally proposed, and hopefully people can be encouraged by this promising anticancer therapy.

Abstract 2D materials and the associated heterostructures define an ideal material platform for investigating physical and chemical properties, and exhibiting new functional applications in (opto)electronic devices, electrocatalysis, and energy storage. 2D transition metal dichalcogenides (2D TMDs), as a member of the 2D materials family including 2D semiconducting TMDs (s‐TMDs) and 2D metallic/semimetallic TMDs (m‐TMDs) have attracted considerable attention in the scientific community. Over the past decade, the 2D s‐TMDs have been extensively researched and reviewed elsewhere. Because of their distinctive physical properties including intrinsic magnetism, charge‐density‐wave order and superconductivity, and potential applications, such as high‐performance electronic devices, catalysis, and as metal electrode contacts, 2D m‐TMDs have grabbed widespread attention in recent years. However, reviews demonstrating the m‐TMDs systematically and comprehensively have been rarely reported. Here, the recent advances in 2D m‐TMDs in the aspects of their unique structures, synthetic approaches,…

Abstract The emerging solar desalination by interfacial evaporation shows great potential for alleviating the global freshwater crisis. However, salt deposition on the whole evaporation surface during steam generation leads to a deterioration in the evaporation rate and long‐term stability. Herein, it is demonstrated that a hydrogel‐based 3D structure can serve as an efficient and stable solar evaporator by salt localized crystallization for high‐salinity brine desalination. Under the function of micron‐grade brine transport management and edge‐preferential crystallization promoted by this novel design, this 3D hydrogel evaporator exhibits a superior salt‐resistant property without salt deposition on the photothermal surface even in 20 wt% brine for continuous 24‐h illumination. Moreover, by virtue of the synergistic effect of the promising 3D structure and excellent water transport of hydrogel, the proposed evaporator possesses an excellent evaporation performance achieving 2.07 kg m −2 h −1 on average in a high‐salinity brine (from 10 to 25 wt% NaCl) under 1 sun irradiation, among…

Abstract Environmental friendly metal halides have become emerging candidates as energy downconverting emitters for lighting and X‐ray imaging applications. Herein, luminescent single crystals of tetramethylammonium manganese chloride (C 4 H 12 NMnCl 3 ) and tetraethylammonium bromide ((C 8 H 20 N) 2 MnBr 4 ) are synthesized via a facile room‐temperature evaporation method. C 4 H 12 NMnCl 3 and (C 8 H 20 N) 2 MnBr 4 with octahedrally and tetrahedrally coordinated Mn 2+ have correspondingly exhibited red and green emission peaking at 635 and 515 nm both originating from 4 T 1 – 6 A 1 transition of Mn 2+ with high photoluminescence quantum yield (PLQY) of 91.8% and 85.1% benefiting from their specific crystal structures. Thanks to their strong photoexcitation under blue light, high PLQY, tunable emission spectra, good environmental stability, the white light‐emitting diode based on blending of C 4 H 12 NMnCl 3 and (C 8 H 20 N) 2 MnBr 4 delivers an outstanding luminous efficacy of 96 lm W −1 , approaching commercial level, and shows no obvious photoluminescence intensity degradation…

Abstract High theoretical capacity and high energy density make lithium sulfur (Li‐S) batteries a competitive candidate for next‐generation energy storage systems. However, achieving the practical application of Li‐S batteries is still a huge challenge due to some inevitable obstacles. Poor conductivity of active sulfur, large volume expansion of cathode, and severe shuttle effect of lithium polysulfides (LiPSs) greatly limit the capacity of cells and lead to unsatisfied cycle performance. Therefore, various sulfur host materials have been proposed and investigated, which should possess good conductivity, porous structure, and strong immobilization capability for LiPSs. Unfortunately, it is incompetent to cover all the advantages mentioned above for pristine materials. Heteroatom doping fundamentally manipulates the electronic structure and polarity of materials, leading to some unprecedented properties, and subsequent enhancement in electrochemical performance. This review systematically summarizes the recent progress of heteroatom (metal single atom and non‐metal atom) doping in…

Abstract Although some strategies have been triggered to address the intrinsic drawbacks of zinc (Zn) anodes in aqueous Zn‐ion batteries (ZIBs), the larger issue of Zn anodes unable to cycle at a high current density with large areal capacity is neglected. Herein, the zinc phosphorus solid solution alloy (ZnP) coated on Zn foil (Zn@ZnP) prepared via a high‐efficiency electrodeposition method as a novel strategy is proposed. The phosphorus (P) atoms in the coating layer are beneficial to fast ion transfer and reducing the electrochemical activation energy during Zn stripping/plating processes. Besides, a lower energy barrier of Zn 2+ transferring into the coating can be attained due to the additional P. The results show that the as‐prepared Zn@ZnP anode in the symmetric cell can be cycled at a current density of 15 mA cm −2 with an areal capacity of 48 mAh cm −2 (depth of discharge, DOD ≈ 82%) and even at an ultrahigh current density of 20 mA cm −2 and DOD ≈ 51%. Importantly, a discharge capacity of 154.4 mAh g −1 in the Zn/MnO 2 full cell can be attained after 1000 cycles at 1 A g…

Abstract Bacterial infection can cause chronic nonhealing wounds, which may be a great threat to public health. It is highly desirable to develop an injectable wound dressing hydrogel with multifunctions including self‐healing, remodeling, antibacterial, radical scavenging ability, and excellent photothermal properties to promote the regeneration of damaged tissues in clinical practice. In this work, dopamine‐modified gelatin (Gel‐DA) is employed for the first time as a biotemplate for enhancing the biomineralization ability of gelatin to synthesize dopamine‐modified gelatin@Ag nanoparticles (Gel‐DA@Ag NPs). Further, the prepared Gel‐DA@Ag NPs with antioxidant activity and near‐infrared (NIR) laser irradiation synergistic antibacterial behavior are fixed in the guar gum based hydrogels through the formation of borate/didiol bonds to possess remolding, injectable, and self‐healing performance. In addition, the multifunctional hydrogels can completely cover the irregular wound shape to prevent secondary injury. More importantly, these hydrogel platforms under NIR can significantly…

Abstract A superelastic aerogel with fast shape recovery performance from large compressive strain is highly desired for numerous applications such as thermal insulation in clothing, high‐sensitive sensors, and oil contaminant removal. Fabrication of superelastic cellulose nanofibrils (CNF) aerogels is challenging as the CNF can assemble into non‐elastic sheet‐like cell walls. Here, a dual ice‐templating assembly (DITA) strategy is proposed that can control the assembly of CNF into sub‐micrometer fibers by extremely low temperature freezing (–196 °C), which can further assemble into an elastic aerogel with interconnected sub‐micron fibers by freezer freezing (−20 °C) and freeze drying. The CNF aerogel from the DITA process demonstrates isotropic superelastic behavior that can recover from over 80% compressive strain along both longitudinal and cross‐sectional directions, even in an extremely cold liquid nitrogen environment. The elastic CNF aerogel can be easily modified by chemical vapor deposition of organosilane, demonstrating superhydrophobicity (164° water contact angle), high…

Abstract Efficient oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) processes highly rely on the rational design and synthesis of high‐performance electrocatalysts. Herein, comprehensive characterizations and density functional theory (DFT) calculations are combined to verify the important roles of the crystallinity and oxygen vacancy levels of Co(II) oxide (CoO) on ORR and OER activities. A facile and controllable vacuum‐calcination strategy is utilized to convert Co(OH) 2 into oxygen‐defective amorphous‐crystalline CoO (namely ODAC‐CoO) nanosheets. With the carefully controlled crystallinity and oxygen vacancy levels, the optimal ODAC‐CoO sample exhibits dramatically enhanced ORR and OER electrocatalytic activities compared with the pure crystalline CoO counterpart. The assembled liquid and quasi‐solid‐state Zn–air batteries with ODAC‐CoO as cathode material achieve remarkable specific capacity, power density, and excellent cycling stability, outperforming the benchmark Pt/C + IrO 2 catalysts. This study theoretically proposes and experimentally demonstrates…

Abstract The rational design of effective catalysts for sluggish oxygen evolution reactions (OERs) is desired but challenging. Nickel‐iron (NiFe) (oxy)hydroxides are promising pre‐electrocatalysts for alkaline OER. However, OER performances are limited by the slow reconstruction process to generate active species of high‐valance NiFe oxyhydroxides. In this work, a sulfate ion (SO42−) modulated strategy is developed to boost the OER activity of NiFe (oxy)hydroxide by accelerating the electrochemical reconstruction of pre‐catalyst and stabilizing the reaction intermediate of OOH* during OER. The SO42− decorated NiFe (oxy)hydroxide catalyst (NF‐S0.15) is fabricated via scalable anodization of NiFe foam in a thiourea‐dissolved electrolyte. The experimental and theoretical investigations demonstrate the dual effect of SO42− on improving OER performances. SO42− leaching is favorable for the electrochemical reconstruction to form active NiFeOOH under OER condition. Simultaneously, the residual SO42− adsorbed on surface can stabilize the intermediate of OOH*, and thus enhance the OER…

Abstract Real‐time monitoring wound status and providing timely therapies with smart wound dressing is a promising way to treat wound infections and accelerate the healing process. Herein, to establish a closed‐loop monitoring and treatment system, a fully integrated, battery‐free, and wireless smart wound dressing for wound infection detection and on‐demand drug delivery is developed using flexible electronics. The smart wound dressing integrated with the near field communication module can realize wireless power harvest and data transmission, on‐site signal processing, and drug delivery control, through the miniaturized circuit and smartphone. The temperature, pH, and uric acid of the wound is detected simultaneously by the developed sensors to assess wound conditions. Meanwhile, the drug delivery electrode in the dressing is used to provide on‐demand infection treatment by the electrically controlled antibiotics delivery. Through in vitro antibacterial experiments and in situ animal studies, it is shown that the dressing can effectively inhibit bacterial growth and accelerate…

Abstract Lithium–sulfur (Li–S) batteries with a theoretical energy density of 2567 Wh kg−1 are very promising next‐generation energy storage systems, but suffer from the insulativity of sulfur and Li2S, the shuttle effect due to the dissolution and migration of polysulfides, and the lithium dendrite issue. MXenes, a family of 2D transition metal carbides/nitrides, which have metallic conductivity, structural variety, strong chemical adsorption ability to polysulfides, effective catalytic effect for fast kinetics, and inducing effect for uniform growth of Li, exhibit promising potential for high‐performance Li–S batteries. In this review, the recent progress and achievements of MXene‐based Li–S batteries are summarized, including the use of MXenes in sulfur cathode, interlayer between cathode and separator, and Li anode. The architecture construction and chemical modification of MXenes, as well as hybridization with other materials are demonstrated. The enhancement on electrochemical performance and the related mechanisms of MXenes and MXene‐based composites are discussed. Finally,…

Abstract 2D materials, such as graphene, transition metal dichalcogenides, black phosphorus, and tellurium, have been demonstrated to be promising building blocks for the fabrication of next‐generation high‐performance infrared (IR) photodetectors with diverse device architectures and impressive device performance. Integrating IR photodetectors with nanophotonic structures, such as surface plasmon structures, optical waveguides, and optical cavities, has proven to be a promising strategy to maximize the light absorption of 2D absorbers, thus enhancing the detector performance. In this review, the state‐of‐the‐art progress of IR photodetectors is comprehensively summarized based on 2D materials and nanophotonic structures. First, the advantages of using 2D materials for IR photodetectors are discussed. Following that, 2D material‐based IR detectors are classified based on their composition, and their detection mechanisms, key figures‐of‐merit, and the principle of absorption enhancement are discussed using nanophotonic approaches. Then, recent advances in 2D material‐based IR…

Abstract Despite the impressive merits of low‐cost and high‐safety electrochemical energy storage for aqueous zinc ion batteries, researchers have long struggled against the unresolved issues of dendrite growth and the side reactions of zinc metal anodes. Herein, a new strategy of zinc‐electrolyte interface charge engineering induced by amino acid additives is demonstrated for highly reversible zinc plating/stripping. Through electrostatic preferential absorption of positively charged arginine molecules on the surface of the zinc metal anode, a self‐adaptive zinc‐electrolyte interface is established for the inhibition of water adsorption/hydrogen evolution and the guidance of uniform zinc deposition. Consequently, an ultra‐long stable cycling up to 2200 h at a high current density of 5 mA cm−2 is achieved under an areal capacity of 4 mAh cm−2. Even cycled at an ultra‐high current density of 10 mA cm−2, 900 h‐long stable cycling is still demonstrated, demonstrating the reliable self‐adaptive feature of the zinc‐electrolyte interface. This work provides a new perspective of interface…

Abstract Novel earth‐abundant metal sulfate‐containing high entropy sulfides, FeNiCoCrXS 2 (where X = Mn, Cu, Zn, or Al), are synthesized via a two‐step solvothermal method. It is shown that sulfate‐containing FeNiCoCrMnS 2 exhibits superior oxygen evolution reaction (OER) activity with an exceptionally low overpotential of 199, 246, 285, and 308 mV at current densities of 10, 100, 500, and 1000 mA cm –2 , respectively, and surpassing its unary‐, binary‐, ternary‐, and quaternary‐metal counterparts. The electrocatalyst yields exceptional stability after 12 000 cycles and 55 h of durability even at a high current density of 500 mA cm –2 . Various in situ and ex situ analyses are used to investigate the self‐reconstruction of the sulfides during the OER for the first time. The resulting metal (oxy)hydroxide is believed to be the true active center for OER. The remaining sulfate also contributes to the catalytic activity. Density function theory calculation is in good agreement with the experimental result. The extraordinary OER performance of the high entropy sulfide brings a great…

Abstract It is a well‐known fact that the pronounced photogenerated charge recombination and poor light absorption are the main bottlenecks of photocatalysis applications. The conventional approaches to address these problems involve bandgap engineering and suppression of charge recombination after light irradiation, which results in an enhancement in the photocatalytic performance of the materials. However, the most essential aspect of surface modification to engineer active sites on the catalyst surface is generally not given much importance. Contrary to this, defect engineering is another approach by which the optical, charge separation, and surface properties of the photocatalytic materials can be tuned. In this review article, the effect of the introduction of vacancies on the photocatalytic properties of selected semiconductor materials, viz., metal oxides, perovskite oxides, metal sulfides, oxyhalides, and nitrides is comprehensively summarized. The engineering of vacancies in these materials not only improves their optical and charge transfer properties but also affects the…

Abstract Today, there is an urgent demand to develop all solid‐state lithium‐ion batteries (LIBs) with a high energy density and a high degree of safety. The core technology in solid‐state batteries is a solid‐state electrolyte, which determines the performance of the battery. Among all the developed solid electrolytes, composite polymer electrolytes (CPEs) have been deemed as one of the most viable candidates because of their comprehensive performance. In this review, the limitations of traditional solid polymer electrolytes and the recent progress of CPEs are introduced. The effect and mechanism of inorganic fillers to the various properties of electrolytes are discussed in detail. Meanwhile, the factors affecting ionic conductivity are intensively reviewed. The recent representative CPEs with synthetic fillers and natural clay‐based fillers are highlighted because of their great potential. Finally, the remaining challenges and promising prospects are outlined to provide strategies to develop novel CPEs for high‐performance LIBs.

Abstract Biocompatible hydrogel adhesives with multifunctional properties, including injectability, fast self‐healing, and suitable on‐demand detachment, are highly desired for minimally invasive procedures, but such materials are still lacking. Herein, an injectable self‐healing biocompatible hydrogel adhesive with thermoresponsive reversible adhesion based on two extracellular matrix‐derived biopolymers, gelatin and chondroitin sulfate, is developed to be used as a surgical adhesive for sealing or reconnecting ruptured tissues. The resulting hydrogels present good self‐healing and can be conveniently injected through needles. The strong tissue adhesion at physiological temperatures originates from the Schiff base and hydrogen bonding interactions between the hydrogel and tissue that can be weakened at low temperatures, thereby easily detaching the hydrogel from the tissue in the gelation state. In vivo and ex vivo rat model show that the adhesives can effectively seal bleeding wounds and fluid leakages in the absence of sutures or staples. Specifically, a proof of concept…

Abstract Radiative cooling is a promising passive cooling technology that reflects sunlight and emits heat to deep space without any energy consumption. Current research mainly focuses on cooling non‐heat‐generating objects (e.g., water) to a deep subambient temperature under sunlight. Toward real‐world applications, however, cooling outdoor objects that generate tremendous heat and have a temperature higher than ambient (e.g., communication base stations and data centres) remains a challenge. Herein, a scalable photonic film is prepared by introducing 2D dielectric nanoplates with high backward scattering efficiency into a polymer using a simulation aided thermo‐optical design. It is demonstrated that the dielectric nanoplates can break the trade‐off between optical reflection and thermal dissipation of conventional radiative coolers. The photonic film exhibits superior solar reflectance (98%) and has a stronger heat dissipation ability compared to the matrix. It exhibits ≈4 °C subambient cooling performance under direct sunlight and ≈9 °C cooling performance at night. Moreover, it…

Abstract The rapidly growing demand for wearable and portable electronics has driven the recent revival of flexible Zn‐ion batteries (ZIBs). However, issues of dendrite growth and low the flexibility of Zn metal anode still impede their practical application. Herein, 3D nitrogen‐doped vertical graphene nanosheets in situ grown on carbon cloth (N‐VG@CC) are proposed to enable uniform Zn nucleation, thereby obtaining a dendrite‐free and robust Zn anode. The introduced zincopilic N‐containing groups in N‐VG effectively reduce the Zn nucleation overpotential by enhancing the interaction between Zn 2+ ion and carbon substrate, as confirmed by density functional theory calculations, thus achieving uniform distribution of Zn nucleus. Moreover, the 3D nanosheet arrays can homogenize electric distribution, which optimizes the subsequence Zn deposition process and realizes the highly reversible Zn plating/stripping process. Consequently, the as‐prepared Zn@N‐VG@CC anode exhibits an improved overall electrochemical performance compared with Zn@CC. As a proof‐of‐concept application, the…

Abstract Covalent organic frameworks (COFs) have emerged as an exciting new class of porous materials constructed by organic building blocks via dynamic covalent bonds. They have been extensively explored as potentially superior candidates for electrode materials, electrolytes, and separators, due to their tunable chemistry, tailorable structures, and well‐defined pores. These features enable rational design of targeted functionalities, facilitate the penetration of electrolytes, and enhance ion transport. This review provides an in‐depth summary of the recent progress in the development of COFs for diverse battery applications, including lithium‐ion, lithium–sulfur, sodium‐ion, potassium‐ion, lithium–CO 2 , zinc‐ion, zinc–air batteries, etc. This comprehensive synopsis pays particular attention to the structure and chemistry of COFs and novel strategies that have been implemented to improve battery performance. Additionally, current challenges, possible solutions, and potential future research directions on COFs for batteries are discussed, laying the groundwork for future advances…

Abstract Conductive hydrogels (CHs) have been highlighted in the design of flexible strain sensors and stretchable triboelectric nanogenerators (TENGs) on the basis of their excellent physicochemical properties such as large stretchability and high conductivity. Nevertheless, the incident freezing and drying behaviors of CHs by using water solvent as the dispersion medium limit their application scopes significantly. Herein, an environment tolerant and ultrastretchable organohydrogel is demonstrated by a simple solvent‐replacement strategy, in which the partial water in the as‐synthesized polyacrylamide/montmorillonite/carbon nanotubes hydrogel is replaced with the glycerol, leading to excellent temperature toleration (−60 to 60 °C) and good stability (30 days under normal environment) without sacrificing the stretchability and conductivity. The organohydrogel exhibits an ultrawide strain sensing range (0–4196%) with a high sensitivity of 8.5, enabling effective detection and discrimination of human activities that are gentle or drastic under various conditions. Furthermore, the…

Abstract The detrimental hydrogen evolution side reaction is one of the major issues hindering the commercialization of Zn metal anode in high‐safety and low‐cost rechargeable aqueous batteries. Herein, the authors present a Sn alloying approach to effectively inhibit the hydrogen evolution and dendrite growth of the Zn metal anode. Through in situ monitoring of the hydrogen production during repeated plating/stripping tests, it is quantitatively demonstrated that the hydrogen evolution of alloy electrode with appropriate Sn amount is only half of that of pure Zn electrode. Furthermore, the Sn alloying allows for favorable Zn nucleation sites, lowering the Zn nucleation energy barrier and promoting more uniform Zn deposition. The Zn‐Sn alloy electrode offers much‐improved plating/stripping cycling, that is, over 240 h at 5 mA cm −2 and 35.2% depth of discharge. This work provides a practically viable strategy to stabilize Zn metal electrode in rechargeable aqueous batteries.

Abstract Electrochemical carbon dioxide reduction reaction (CO 2 RR) offers a promising way of effectively converting CO 2 to value‐added chemicals and fuels by utilizing renewable electricity. To date, the electrochemical reduction of CO 2 to single‐carbon products, especially carbon monoxide and formate, has been well achieved. However, the efficient conversion of CO 2 to more valuable multicarbon products (e.g., ethylene, ethanol, n ‐propanol, and n ‐butanol) is difficult and still under intense investigation. Here, recent progresses in the electrochemical CO 2 reduction to multicarbon products using copper‐based catalysts are reviewed. First, the mechanism of CO 2 RR is briefly described. Then, representative approaches of catalyst engineering are introduced toward the formation of multicarbon products in CO 2 RR, such as composition, morphology, crystal phase, facet, defect, strain, and surface and interface. Subsequently, key aspects of cell engineering for CO 2 RR, including electrode, electrolyte, and cell design, are also discussed. Finally, recent advances are summarized…

Abstract UiO‐66‐NH 2 /black phosphorus quantum dots (MOF/BPQDs) heterojunctions are anchored on the carboxyl cellulose nanofiber (CNF) aerogel with high porosity (>98%) to fabricate high‐efficiency uranium adsorbents (BP@CNF‐MOF). CNF aerogels possess abundant carboxyl groups, which can serve as nucleation centers to in situ synthesize UiO‐66‐NH 2 with smaller crystal size, high mass loading, and good adhesion. BP@CNF‐MOF demonstrates good mechanical flexibility and minimal MOF loss from the CNF aerogel, both of which result from the mutual physical interactions and entanglements of CNFs as well as strong binding interactions between MOF crystals and CNF aerogel. Owing to the excellent heterogeneous photocatalytic activity of MOF/BPQDs, on one hand, marine bacteria can be effectively destroyed by reactive oxygen species (ROS). On the other hand, the photocatalytic U(VI) reduction to insoluble U(IV) could be facilitated, thereby allowing more binding sites on the MOF crystals for further U(VI) adsorption. Consequently, compared with dark conditions, the adsorption efficiency of the…

Abstract Stretchable self‐healing supercapacitors (SCs) can operate under extreme deformation and restore their initial properties after damage with considerably improved durability and reliability, expanding their opportunities in numerous applications, including smart wearable electronics, bioinspired devices, human–machine interactions, etc. It is challenging, however, to achieve mechanical stretchability and self‐healability in energy storage technologies, wherein the key issue lies in the exploitation of ideal electrode and electrolyte materials with exceptional mechanical stretchability and self‐healing ability besides conductivity. Conductive hydrogels (CHs) possess unique hierarchical porous structure, high electrical/ionic conductivity, broadly tunable physical and chemical properties through molecular design and structure regulation, holding tremendous promise for stretchable self‐healing SCs. Hence, this review is innovatively constructed with a focus on stretchable and self‐healing CH based electrodes and electrolytes for SCs. First, the common synthetic approaches of…

Abstract 2D MXene materials have attracted intensive attention in energy storage application. However, MXene usually undergoes serious face‐to‐face restacking and inferior stability, significantly preventing its further commercial application. Herein, to suppress the oxidation and self‐restacking of MXene, an efficient and fast self‐assembly route to prepare a 3D porous oxidation‐resistant MXene/graphene (PMG) composite with the assistance of an in situ sacrificial metallic zinc template is demonstrated. The self‐assembled 3D porous architecture can effectively prevent the oxidation of MXene layers with no evident variation in electrical conductivity in air at room temperature after two months, guaranteeing outstanding electrical conductivity and abundant electrochemical active sites accessible to electrolyte ions. Consequently, the PMG‐5 electrode possesses a striking specific capacitance of 393 F g −1 , superb rate performance (32.7% at 10 V s −1 ), and outstanding cycling stability. Furthermore, the as‐assembled asymmetric supercapacitor possesses a pronounced energy density of…

Abstract Metasurfaces based on quasi‐bound states in the continuum (quasi‐BICs) constitute an emerging toolkit in nanophotonic sensing as they sustain high quality factor resonances and substantial near‐field enhancements. It is demonstrated that silicon metasurfaces composed of crescent shaped meta‐atoms provide tailored light‐matter interaction controlled by the crescent geometry. Significantly, this metasurface not only exhibits a fundamental quasi‐BIC resonance, but also supports a higher‐order resonance with tunable electromagnetic field enhancement and advantageous properties for sensing. The higher‐order resonance shows twice the sensitivity of the fundamental one for bulk refractive index sensing. It is further demonstrated that both the fundamental and higher‐order resonances can be exploited for sensing ultrathin layers of biomolecules in air and buffer solutions. Specifically, when measuring in buffer solution, the figure of merit of the sensor, defined as the change in the spectral position of the resonance normalized to its full width at half maximum, is a factor of 2.5…

Abstract Hydrogel modified porous matrix with the super‐wetting surface (i.e., super‐hydrophilic/underwater super‐oleophobic) is ideal for oil/water separation. However, the deterioration in mechanical strength and separation efficiency during the swelling process and complicated synthesis procedure limits its industrial application. In this study, a strategy of using ethanol to dynamically regulate the hydrogen bond crosslinking between polyvinyl alcohol (PVA) and tannic acid (TA) is proposed to prepare a “hydrogel paint”, which can be simply applied on the porous substrate surface by different one‐step operations (dipping, brushing, spraying, etc.) without additional cross‐linking. The underline mechanism is attributed to the re‐establishment of intermolecular hydrogen bond mediated cross‐linking between PVA and TA during ethanol evaporation. Consequently, the resultant hydrogel coating exhibits ultra‐high strength (>10 MPa), swelling volume stability, and excellent oil‐water separation efficiency (>99%). This study will provide new insights into the scalable fabrication of…

Abstract Manganese‐based materials are considered potential cathode materials for aqueous zinc ion batteries (ZIBs). However, the dissolution of manganese leading to an abrupt decline of capacity and the sluggish electrochemical reaction kinetics are still the main bottlenecks restricting their further development. Herein, a NiMn‐layered double hydroxide‐derived Ni‐doped Mn 2 O 3 (NM) is developed to suppress the dissolution of manganese. The incorporation of Ni 2+ can promote electronic rearrangement and enhance the conductivity, ultimately improving the reaction kinetics and electrochemical performance of the NM. Moreover, the doped Ni 2+ can effectively stabilize the MnO bond of Mn 2 O 3 by reducing the formation energy. In addition, the storage mechanism based on the simultaneous insertion and transformation of H + and Zn 2+ is demonstrated. Interestingly, the Ni‐doped Mn 2 O 3 shows a high specific capacity of 252 mAh g –1 (0.1 A g –1 ), three times more than the pure Mn 2 O 3 (72 mAh g –1 ). The capacity retention (≈85.6% over 2500 cycles at 1.0 A g –1 ) is also more…

Abstract Anode‐free zinc batteries (AFZBs) are proposed as promising energy storage systems due to their high energy density, inherent safety, low cost, and simplified fabrication process. However, rapid capacity fading caused by the side reactions between the in situ formed zinc metal anode and electrolyte hinders their practical applications. To address these issues, aqueous AFZBs enabled by electrolyte engineering to form a stable interphase are designed. By introducing a multifunctional zinc fluoride (ZnF 2 ) additive into the electrolyte, a stable F‐rich interfacial layer is formed. This interfacial layer can not only regulate the growth orientation of zinc crystals, but also serve as an inert protection layer against side reactions such as H 2 generation. Based on these synergy effects, zinc deposition/dissolution with high reversibility (Coulombic efficiency > 99.87%) and stable cycling performance up to 600 h of are achieved in the electrolyte optimized by ZnF 2 . With this electrolyte, the cycling life of AFZBs is significantly improved. The work may initiate the research…

Abstract The development of multicomponent dielectric composites has become a mainstream approach for obtaining excellent electromagnetic wave (EMW) absorbers. However, conventional component introduction is often performed blindly and based only on semiempirical rules, lacking precise modulation of components, interfaces, and defects during the reaction process. Herein, a competitive reaction mechanism is proposed for the first time, in which not only the metal ion concentration but also its characteristic are two feasible parameters to control the components, interfaces, and defects to tailor the EMW absorption performances of Cu‐based binary metal sulfides. The appropriate heterogeneous interfaces and components and the abundant defects can synergistically benefit the EMW absorption capacity by forming perfect impedance matching and multiple dielectric polarizations. As a result, combined with these advantages, an effective absorption band) of 6.80 GHz (6.3–13.1 GHz) is achieved at 2.80 mm for Cu–Co binary metal sulfide, showing the sole middle‐frequency broadband absorption of…

Abstract The reduced graphene oxide (rGO) sponges exhibit exciting electromagnetic absorption (MA) performance in high‐frequency range. However, it is still a great challenge to realize desirable MA property at low frequency (2–4 GHz) due to the great difficulty in balancing the good interfacial impedance matching and strong dielectric loss. Herein, the MA metamaterials based on rGO sponge with different unit shapes are reported. The relationship between the unit shape and MA performance is explored by experiment and simulation. The results show that frustum pyramid metamaterial exhibits ultrabroad band MA; the qualified absorption (the reflection loss lower than −10 dB) of electromagnetic wave can be achieved at 2.4–40 GHz. The average absorption intensity is −22.9 dB in the band of 2–40 GHz. Moreover, the bandwidth for strong absorption with an absorption rate of 99% (−20 dB) is up to 32 GHz. It is significant that the reflection loss has ignorant change even though the incident angle is increased from 5° to 40°. These are contributed to the excellent impedance matching and strong…

Abstract 2D transition metal carbides/nitrides (MXenes) have excellent physical–chemical properties, which makes them promising for electrochemical energy storage devices. However, because of their inherent self‐stacking and narrow interlayer spacing, it is rarely used in multivalent ion energy storage systems. In this study, fatty diamines and aromatic diamines with different molecular sizes are inserted between MXene interlayers as pillars through a one‐step amination process to inhibit the self‐stacking and obtain different expanded interlayer spacings with improved antioxidant stability. X‐ray diffraction results show that interlayer spacing of MXene increases from 1.23 to 1.40 nm. The p ‐phenylenediamine‐intercalated MXene (PDA‐MXene) exhibits better matching interlayer spacing (1.38 nm) and pore structure for improved electrolyte‐accessible surface area, enhanced charge‐transport properties, and promoted Zn 2+ ions storage. Therefore, zinc‐ion hybrid supercapacitor (ZHSC) using PDA‐MXene as cathode exhibits higher specific capacitance (124.4 F g −1 at 0.2 A g −1 ) in 2 m ZnSO…

Abstract Excessive and unwarranted administration of antibiotics has invigorated the evolution of multidrug‐resistant microbes. There is, therefore, an urgent need for advanced active compounds. Ionic liquids with short‐lived ion‐pair structures are highly tunable and have diverse applications. Apart from their unique physicochemical features, the newly discovered biological activities of ionic liquids have fascinated biochemists, microbiologists, and medical scientists. In particular, their antimicrobial properties have opened new vistas in overcoming the current challenges associated with combating antibiotic‐resistant pathogens. Discussions regarding ionic liquid derivatives in monomeric and polymeric forms with antimicrobial activities are presented here. The antimicrobial mechanism of ionic liquids and parameters that affect their antimicrobial activities, such as chain length, cation/anion type, cation density, and polymerization, are considered. The potential applications of ionic liquids in the biomedical arena, including regenerative medicine, biosensing, and…

Abstract Flexible tactile sensors are garnering substantial interest for various promising applications, including artificial intelligence, prosthetics, healthcare monitoring, and human–machine interactions (HMI). However, it still remains a critical challenge in developing high‐resolution tactile sensors without involving high‐cost and complicated manufacturing processes. Herein, a flexible high‐resolution triboelectric sensing array (TSA) for self‐powered real‐time tactile sensing is developed through a facile, mask‐free, high‐efficient, and environmentally friendly laser direct writing technique. A 16 × 16 pixelated TSA with a resolution of 8 dpi based on patterned laser‐induced graphene (LIG) electrodes (7 Ω sq −1 ) is fabricated by the complementary intersection overlapping between upper and lower aligned semicircular electrode arrays. With the especially patterning design, the complexity of TSA and the number of data channels is reduced. Meanwhile, the TSA platform exhibits excellent durability and synchronicity and enables the achievement of real‐time visualization of…

Abstract Asymmetric supercapacitors (ASCs) can substantially broaden their working voltage range, benefiting from the advantages of both cathode and anode while breaking through the energy storage limitations of corresponding symmetric cells. Wide voltage aqueous ASCs hold great promise for future electronic systems that require satisfied energy density, power density, and cycle life, due to the advantages of aqueous electrolyte in terms of low cost, operational safety, facile manufacture, environment‐friendly, and high ionic conductivity. This review will first briefly present an overview of the historical developments, charge storage mechanisms, and matching principles of wide voltage aqueous ASCs. Then, the cathode and anode materials with wide potential windows for building wide voltage aqueous ASCs over the last few decades are summarized. The next section details the optimization methods of aqueous electrolyte related to wide voltage aqueous ASCs. In addition, the basic device configurations of wide voltage aqueous ASCs are classified and discussed. Furthermore, several…

Abstract Real‐time monitoring of wound healing remains a major challenge in clinical tissue regeneration, calling the need for the development of biomaterial‐guided on‐site monitoring wound healing technology. In this study, multifunctional double colorimetry‐integrated polyacrylamide‐quaternary ammonium chitosan‐carbon quantum dots (CQDs)‐phenol red hydrogels are presented, aiming to simultaneously detect the wound pH level, reduce bacterial infection, and promote wound healing. The hybridization of CQDs and pH indicator (phenol red) with the hydrogels enables their high responsiveness, reversibility, and accurate indication of pH variability to reflect the dynamic wound status in the context of both ultraviolet and visible light. Furthermore, these visual images can be collected by smartphones and converted into on‐site wound pH signals, allowing for a real‐time evaluation of the wound dynamic conditions in a remote approach. Notably, the hydrogels exhibit excellent hemostatic and adhesive properties, maintain sufficient wound moisture, and promote wound healing via their high…

Abstract Thermal camouflage has attracted increasing attention owing to the rapid development of infrared (IR) surveillance technologies. Various materials and systems have been developed to date, but the realization of high‐temperature thermal camouflage using ultrathin film/coating remains a great challenge; this is of great significance, especially for IR stealth in military equipment. This work demonstrates a series of ultrathin Ti 3 C 2 T x MXene films (as low as 1 µm) with superior high‐temperature indoor/outdoor thermal camouflage performance: wide camouflage temperature range (from below −10 °C to over 500 °C), large reduction in radiation temperature (exceeding 300 °C for objects with temperatures over 500 °C), long‐term high‐temperature or fire stability, multifunctionality including disguised Joule heating capability, and high electromagnetic interference shielding efficiency. The superior high‐temperature thermal camouflage performance of the ultrathin MXene film is attributed to its low mid‐IR emissivity (0.19), which is comparable to that of stainless steel but far…

Abstract Quasi‐zero‐stiffness (QZS) isolators of high‐static‐low‐dynamic stiffness play an important role in ultra‐low frequency vibration mitigation. While the current designs of QZS mainly exploit the combination of negative‐stiffness corrector and positive‐stiffness element, and only have a single QZS working range, here a class of tailored mechanical metamaterials with programmable QZS features is proposed. These programmed structures contain curved beams with geometries that are specifically designed to enable the prescribed QZS characteristics. When these metamaterials are compressed, the curved beams reach the prescribed QZS working range in sequence, thus enabling tailored stair‐stepping force‐displacement curves with multiple QZS working ranges. Compression tests demonstrate that a vast design space is achieved to program the QZS features of the metamaterials. Further vibration tests confirm the ultra‐low frequency vibration isolation capability of the proposed mechanical metamaterials. The mechanism of QZS stems solely from the structural geometry of the curved beams and…

Abstract As a new 2D material, MXene (Ti 3 C 2 T x ) shows great potential as a smart multifunctional humidity‐responsive actuator due to its high hydrophilicity and conductivity but suffers from ambient oxidation and mechanical brittleness. Inspired by the mussels, the authors overcome these weaknesses by designing and fabricating a nacre‐like and lamellar‐structured composite film that consists of polydopamine‐modified MXene and bacterial cellulose nanofibers, which shows improved properties as a moisture‐driven actuator. The actuator has high conductivity (2848 S cm –1 ), excellent tensile strength (406 MPa), and toughness (15.3 MJ m –3 ). Moreover, the actuator is highly sensitive to moisture with the advantages of fast response (1.6 s), large deformation (176°), and high actuation force output (6.5 N m –2 ). It is additionally demonstrated that the actuator works as the electrical switch, robotic arm, and motor in a moisture‐driven manner. Overall, it is believed that this work improves the drawbacks of current MXene‐based actuators, laying the groundwork for their wider…

Abstract Polymeric g‐C3N4 is a promising visible‐light‐responsive photocatalyst; however, the fast recombination of charge carriers and moderate oxidation ability remarkably restrict its photocatalytic oxidation efficiency towards organic pollutants. To overcome these drawbacks, a self‐modification strategy of one‐step formaldehyde‐assisted thermal polycondensation of molten urea to prepare carbon‐deficient and oxygen‐doped g‐C3N4 (VC‐OCN) is developed, and the carbon vacancy concentration is well‐controlled by changing formaldehyde dosage. The VC‐OCN catalysts exhibit interesting carbon vacancy concentration‐dependent photocatalytic removal efficiency to p‐nitrophenol (PNP) and atrazine (ATN), in which VC‐OCN15 with appropriate carbon vacancy concentration displays significantly higher pollutant removal efficiency than bulk g‐C3N4. The apparent first‐order rate constant of VC‐OCN15 for PNP and ATN removal is 4.4 and 5.2 times higher than that of bulk g‐C3N4. A combination of the experimental results and theoretic calculations confirm that the synergetic effect of carbon vacancies…

Abstract Engineering the structure and chemistry of solid electrolyte interface (SEI) on electrode materials is crucial for rechargeable batteries. Using hard carbon (HC) as a platform material, a correlation between Na + storage performance, and the properties of SEI is comprehensively explored. It is found that a “good” SEI layer on HC may not be directly associated with certain kinds of SEI components, such as NaF and Na 2 O. Whereas, arranging nano SEI components with refined structures constructs the foundation of “good” SEI that enables fast Na + storage and interface stability of HC in Na‐ion batteries. A layer‐by‐layer SEI on HC with inorganic‐rich inner layer and tolerant organic‐rich outer flexible layer can facilitate excellent rate and cycling life. Besides, SEI layer as the gate for Na + from electrolyte to HC electrode can modulate interfacial crystallographic structures of HC with pillar‐solvent that function as “pseudo‐SEI” for fast and stable Na + storage in optimal 1 m NaPF 6 ‐TEGDME electrolytes. Such a layer‐by‐layer SEI combined with a “pseudo‐SEI” layer for HC…

Abstract Bistable mechanical systems having two local minima of potential energy can rest in either of the two stable equilibrium states in the absence of external loadings. A snap‐through action may occur under suitable stimuli and/or loading, during which such systems exhibit distinct properties from linear structures. Such kinds of structures have been widely exploited for designing advanced functional systems for a variety of applications. Here, the advances of bistable structures are summarized for novel advanced functional systems, including actuators, energy harvesters, microelectromechanical systems (MEMS), robotics, energy absorbers, and programmable devices as well as metamaterials. The controllable snap‐through motions are highlighted in the nonlinear structures of bistability/multistability. Finally, the major principles, structures, pros and cons, and the future research directions along with its challenges are discussed.

Abstract Interfacial engineering of heterostructured catalysts has attracted great interest in enabling both hydrogen and oxygen evolution reactions (HER and OER), by fine tuning of the interfacial geometry and electronic structures. However, they are not well structured for high‐performing bifunctionalities, largely due to the confined single particle morphologies, where the exposed surfaces and interfaces are limited. Herein, a hollow nanoframing strategy is purposely devised for interconnected Co3O4–Mo2N heterostructures that are designed with interfacial charge transfer from Mo2N to Co3O4, as rationalized by theoretical calculations and confirmed by X‐ray photoelectron spectroscopy analyses. It is shown that by the controllable pyrolysis of bimetallic Mo–Co Prussian blue analogue nanoframes (NFs) with an optimal Mo/Co ratio, the desired nanoframes of Co3O4–Mo2N heterostructure are successfully formed. The as‐synthesized Co3O4–Mo2N NFs not only inherit the functionalities of individual components and the electrolyte‐accessible nanoframe structure, and they also give an ideal…

Abstract Polymeric dielectrics have attracted intensive attention worldwide because of their huge potential for advanced energy storage capacitors. Thus far, various effective strategies have been developed to improve the inherent low energy densities of polymer dielectrics. However, enhanced energy density is always accompanied by suppressed discharge efficiency, which is detrimental to practical applications and deserves considerable concern. Targeting at achieving simultaneous high energy density and high discharge efficiency, the unique design of asymmetric all‐polymer trilayer composite consisting of a transition layer sandwiched by a linear dielectric layer and a nonlinear dielectric layer is herein reported. It is demonstrated that the nonlinear dielectric layer offers high energy density, while the linear dielectric layer provides high discharge efficiency. Especially, the transition layer can effectively homogenize the electric field distribution, resulting in greatly elevated breakdown strength and improved energy density. In particular, a high efficiency of 89.9% along…

Abstract The conventional environment polluting energy sources and the continuous growing energy demand compelled researchers to find alternative energy sources. Therefore, in recent years, extensive research has been carried out in synthesizing catalysts for energy conversion applications. This review focuses on the application of various electrodeposition methods in the synthesis of energy‐related electrocatalyst and briefly discusses different electrocatalyst characterization techniques. Further, the influence of various parameters on the electrocatalyst activity and stability is highlighted. Electrocatalyst application in clean energy conversion reactions, such as the hydrogen evolution reaction, oxygen evolution reaction, oxygen reduction reaction, carbon dioxide reduction reaction, nitrogen reduction reaction along with the metal‐air/CO2 battery, are reviewed. Finally, the comparative experimental data are provided as a reference to synthesize the next‐generation electrodeposited electrocatalyst in clean energy conversions and beyond.

Abstract The design of fluorophores merging circularly polarized luminescence and thermally activated delayed fluorescence properties has recently emerged as a promising direction for the development of efficient CP‐Organic Light‐Emitting Diodes (CP‐OLEDs). This progress report gives an overview of the molecular designs explored to obtain CP‐TADF properties, of their performances as chiral emitters in CP‐OLEDs, and discusses future challenges for this burgeoning field of research.

Abstract Microfluidic hydrogel microspheres have been broadly studied across a wide range of industries and applications, and their use in the medical field, including control cells and drug delivery, is increasing. The usual design of these materials is intended to enable the efficient and smart encapsulation of cells and/or drugs in microspheres in which the functionalities and features are effectively controlled, lending itself some unique properties. These characteristics promote exchanges and cooperation in multiple disciplines and boost the development of precision medicine, new manufacturing technologies, and applied materials. This review begins with a discussion of microfluidic hydrogel microspheres and then introduces the preparation equipment, main principles, and related characteristics of the microspheres. Furthermore, the medical applications of microfluidic hydrogel microspheres for delivering cells and drugs are emphasized. Finally, this review discusses perspectives and future directions for accelerating the development and application of microfluidic hydrogel…

Abstract Aqueous Zn‐ion batteries have been considered as promising alternatives to Li‐ion batteries due to their abundant reserves, low price, and high safety. However, Zn anode shows poor reversibility and cycling stability in most conventional aqueous electrolytes. Here, a new type of aqueous Zn‐ion electrolyte based on ZnCl2–acetamide deep eutectic solvent with both environmental and economic friendliness has been prepared. The water molecule introduced in the “water‐in‐deep eutectic solvent” electrolyte could reduce the Zn2+ desolvation energy barrier by regulating Zn2+ solvation structure to promote uniform Zn nucleation. Zn anode shows improved electrochemical performance (≈98% Coulombic efficiency over 1000 cycles) in the electrolyte whose molar ratio of ZnCl2:acetamide:H2O is 1:3:1. The assembled full battery composed of phenazine cathode and Zn anode could stably cycle over 10 000 cycles with a high capacity retention of 85.7%. Overall, this work offers new insights into exploring new green electrolyte systems for Zn‐ion batteries.

Abstract The recent dramatic increase in research on isolated metal atoms has received extensive scientific interest in the new frontier of single‐atom catalysis. As newly advanced materials in catalysis, single‐atom catalysts (SACs) have received enormous interest from the perspectives of both scientific research and industrial applications due to their remarkable activity. In addition, other catalytic properties of single metal atoms, including stability and selectivity, can be further improved by tuning their electronic/geometric structures and modulating the metal–support interactions. SACs usually consist of dispersed atoms and appropriate support materials, which are employed to anchor, confine, and/or coordinate with isolated metal atoms. Therefore, the nature of single metal sites allows acquiring a maximum atom utilization approaching 100%, which is of significance, particularly for the development of noble‐metal‐based catalysts. In order to systematically understand the structure–property relationships and the underlying catalytic mechanisms relationship of SACs, the…

Abstract Electronic skin (e‐skin) is driving significant advances in flexible electronics as it holds great promise in health monitoring, human–machine interfaces, soft robotics, and so on. Flexible sensors that can detect various stimuli or have multiple properties play an indispensable role in e‐skin. Despite tremendous research efforts devoted to flexible sensors with excellent performance regarding a certain sensing mode or property, emerging e‐skin demands multifunctional flexible sensors to be endowed with the skin‐like capability and beyond. Considering outstanding superiorities of electrical conductivity, chemical stability, and ease of functionalization, carbon materials are adopted to implement multifunctional flexible sensors. In this review, the latest advances of carbon‐based multifunctional flexible sensors with regard to the types of detection modes and abundant properties are introduced. The corresponding preparation process, device structure, sensing mechanism, obtained performance, and intriguing applications are highlighted. Furthermore, diverse e‐skin systems by…

Abstract The development of rechargeable batteries with high‐energy density is critical for future decarbonization of transportation. Anode‐free Li‐ion batteries, using a bare current collector at the anode side without any excess of Li, provide the highest volumetric energy density (>1500 Wh L−1) among all possible cell configurations. Furthermore, elimination of the anode material coating reduces material consumption and greatly simplifies cell production, which in turn lowers costs. Although significant progress has been made recently by the application of modified current collectors, optimized cycling parameters and improved liquid electrolytes, insufficient efficiencies, and dendritic growth during lithium plating lead to poor cycle life of typically less than 100 cycles as well as safety issues. Alternatively, very recent studies have demonstrated anode‐free solid‐state batteries that combine the benefits of high energy anode‐free cell configuration and solid‐state systems with high safety, exceeding 1000 cycles. This review provides an overview of recent developments toward…

Abstract Realizing ultrathin water and generating an abundant water/air interface in the interconnected pores of photothermal materials is an effective way to boost the solar‐driven water evaporation rate, but still a great challenge. Herein, confinement capillarity (CC) of photothermal thin coating on porous sponge for significantly enhancing the solar‐driven water evaporation is proposed. The thin coating is composed of abundant agminated black/hydrophilic nanoparticles (BHNPs), and the channels among the BHNPs can generate strong capillarity for water transportation. Water can be spontaneously limited and transported among the agminated nanoparticles, rather than fill in the interconnected pores of the sponge. Thus, ultrathin water layer can be realized on the outer/inner surface of the sponge skeleton, without precisely controlling water supply. The thin water layer can not only expose as much evaporation area as possible by increasing the vapor escape channel, but also prevent solar energy to heat excess water. Thanks to the CC, the rate of solar steam generation can be greatly…

Abstract Nickel‐based electrocatalysts are promising candidates for oxygen evolution reaction (OER) but suffer from high activation overpotentials. Herein, in situ structural reconstruction of V‐doped Ni2P pre‐catalyst to form highly active NiV oxyhydroxides for OER is reported, during which the partial dissolution of V creates a disordered Ni structure with an enlarged electrochemical surface area. Operando electrochemical impedance spectroscopy reveals that the synergistic interaction between the Ni hosts and the remaining V dopants can regulate the electronic structure of NiV oxyhydroxides, which leads to enhanced kinetics for the adsorption of *OH and deprotonation of *OOH intermediates. Raman spectroscopy and X‐ray absorption spectroscopy further demonstrate that the increased content of active β‐NiOOH phase with the disordered Ni active sites contributes to OER activity enhancement. Density functional theory calculations verify that the V dopants facilitate the generation of *O intermediates during OER, which is the rate‐determining step for realizing efficient O2 evolution.…

Abstract 2D materials show wide‐ranging physical properties with their electronic bandgaps varying from zero to several electronvolts, offering a rich platform to explore novel electronic and optoelectronic functions. Notably, atomically thin 2D materials are well suited for integration in optoelectronic circuits, because of their ultrathin body, strong light–matter interactions, and compatibility with the current silicon photonic technology. In this paper, an overview of the state of the art of using 2D materials in optoelectronic devices and integration is provided. The optoelectronic properties of 2D materials and their typical electronic and optoelectronic applications including light sources, optical modulators, photodetectors, field‐effect transistors, and logic circuits are summarized. The device configurations, operation mechanisms, and device figures‐of‐merit are introduced and discussed. By discussing the recent advances, future trends, and existing challenges of 2D materials and their optoelectronic devices, this review has provided an insight into the perspectives of 2D…

Abstract Energy‐related problems induced by ever‐continuous fossil consumption have arisen as one of the most challenging issues in the 21 st century, imposing urgent demands on advanced materials to achieve high energy utilization and a sustainable society. In various solar energy utilization and solar‐to‐fuel energy conversion processes, charge carriers are the main and inevitable participators, and the charge dynamics related to their generation, migration, separation, and utilization is the key to advance the material design for settling the above issues. Internal electric field (IEF), also named as built‐in electric field, could guide directional migration of charge carriers, achieving effective charge separation, utilization, and prolonged lifetimes. This critical review begins with the discussion on various modulation strategies toward the IEF together with in‐detail elucidated mechanisms on its formation. Some cascade systems for telling the conclusive role from the induced IEF and the intrinsic design strategy are discussed. Then, a summary of the state‐of‐the‐art advances…

Abstract Infrared photodetectors have been widely applied in various fields, including thermal imaging, biomedical imaging, and communication. Van der Waals (vdW) integration based on 2D materials provides a new solution for high‐performance infrared photodetectors due to the versatile device configurations and excellent photoelectric properties. In recent years, great progress has been made in infrared photodetectors based on vdW integration. In this review, recent progress in vdW integration‐based infrared photodetectors is presented. First, the working mechanisms and advantages of photodetectors with different structures and band alignments are presented. Then, the recent progress of vdW integration‐based infrared photodetectors is reviewed, focusing on 2D/ n D ( n = 0, 1, 2, 3) vdW integration, and the band engineering as well as the performance of the photodetectors are discussed in detail. Finally, a summary is delivered, and the challenges and future directions of vdW integration‐based infrared photodetectors are provided.

Abstract VB‐Group transition metal disulfides (TMDs) are considered excellent materials for electromagnetic wave (EMW) absorption because of their good conductivity and abundant active sites located at their edges and substrates, as compared with VIB‐Group TMDs. Herein, for the first time, EMW absorbers based on VB‐Group NbS 2 nanosheets by using a facile one‐step solvothermal method are successfully prepared. The minimum reflection loss (RL min ) can reach up to 43.85 dB with an effective absorption bandwidth of 6.48 GHz (11.52–18.00 GHz). The remarkable EMW absorption performance can also be reflected in the tunable frequency bands (C‐, X‐, and Ku‐bands), which is achieved by adjusting the contents of materials. Furthermore, the influence of the content of 2H‐phase and 1T‐phase in NbS 2 on the EMW absorption performance is systematically investigated. The hierarchical hollow‐sphere structure of NbS 2 promotes dielectric loss and the multiple reflection and absorption of EMW, and enhances the impedance matching and synergistic attenuation ability. This work demonstrates that the…

Abstract Natural living systems such as wood frogs develop tissues composed of active hydrogels with cryoprotectants to survive in cold environments. Recently, hydrogels have been intensively studied to develop stretchable electronics for wearables and soft robots. However, regular hydrogels are inevitably frozen at the subzero temperature and easily dehydrated, and have weak surface adhesion. Herein, a novel hydrogel‐based ionic skin (iSkin) capable of strain sensing is demonstrated with high toughness, high stretchability, excellent ambient stability, superior anti‐freezing capability, and strong surface adhesion. The iSkin consists of a piece of ionically and covalently cross‐linked tough hydrogel with a thin bioadhesive layer. With the addition of biocompatible cryoprotectant and electrolyte, the iSkin shows good conductivity in wide ranges of relative humidity (15–90%) and temperature (−95–25 °C). In addition, the iSkin can adhere firmly to diverse material surfaces under different conditions, including cloth fabric, skin, and elastomers, in both dry and wet conditions, at…

Abstract Regulating the electron transport layer (ETL) has been an effective way to promote the power conversion efficiency (PCE) of perovskite solar cells (PSCs) as well as suppress their hysteresis. Herein, the SnO2 ETL using a cost‐effective modification material rubidium fluoride (RbF) is modified in two methods: 1) adding RbF into SnO2 colloidal dispersion, F and Sn have a strong interaction, confirmed via X‐ray photoelectron spectra and density functional theory results, contributing to the improved electron mobility of SnO2; 2) depositing RbF at the SnO2/perovskite interface, Rb+ cations actively escape into the interstitial sites of the perovskite lattice to inhibit ions migration and reduce non‐radiative recombination, which dedicates to the improved open‐circuit voltage (Voc) for the PSCs with suppressed hysteresis. In addition, double‐sided passivated PSCs, RbF on the SnO2 surface, and p‐methoxyphenethylammonium iodide on the perovskite surface, produces an outstanding PCE of 23.38% with a Voc of 1.213 V, corresponding to an extremely small Voc deficit of 0.347 V.