The 50 most-cited articles in Journal of The Electrochemical Society, 2020

Energy storage systems with Li-ion batteries are increasingly deployed to maintain a robust and resilient grid and facilitate the integration of renewable energy resources. However, appropriate selection of cells for different applications is difficult due to limited public data comparing the most commonly used off-the-shelf Li-ion chemistries under the same operating conditions. This article details a multi-year cycling study of commercial LiFePO 4 (LFP), LiNi x Co y Al 1−x−y O 2 (NCA), and LiNi x Mn y Co 1−x−y O 2 (NMC) cells, varying the discharge rate, depth of discharge (DOD), and environment temperature. The capacity and discharge energy retention, as well as the round-trip efficiency, were compared. Even when operated within manufacturer specifications, the range of cycling conditions had a profound effect on cell degradation, with time to reach 80% capacity varying by thousands of hours and cycle counts among cells of each chemistry. The degradation of cells in this study was compared to that of similar cells in previous studies to identify universal trends and to provide a…

Presented here, is an extensive 35 parameter experimental data set of a cylindrical 21700 commercial cell (LGM50), for an electrochemical pseudo-two-dimensional (P2D) model. The experimental methodologies for tear-down and subsequent chemical, physical, electrochemical kinetics and thermodynamic analysis, and their accuracy and validity are discussed. Chemical analysis of the LGM50 cell shows that it is comprised of a NMC 811 positive electrode and bi-component Graphite-SiO x negative electrode. The thermodynamic open circuit voltages (OCV) and lithium stoichiometry in the electrode are obtained using galvanostatic intermittent titration technique (GITT) in half cell and three-electrode full cell configurations. The activation energy and exchange current coefficient through electrochemical impedance spectroscopy (EIS) measurements. Apparent diffusion coefficients are estimated using the Sand equation on the voltage transient during the current pulse; an expansion factor was applied to the bi-component negative electrode data to reflect the average change in effective surface area…

The conventional LiPF 6 /carbonate-based electrolytes have been widely used in graphite (Gr)-based lithium (Li) ion batteries (LIBs) for more than 30 years because a stable solid electrolyte interphase (SEI) layer forms on the graphite surface and enables its long-term cycling stability. However, few of these electrolytes are stable under the more stringent conditions needed with a Li metal anode (LMA) and other anodes, such as silicon (Si), which exhibit large volume changes during charge/discharge processes. Many different approaches have been developed lately to stabilize Li metal batteries (LMBs) and Si-based LIBs. From this aspect, localized high-concentration electrolytes (LHCEs) have unique advantages: not only are they stable in a wide electrochemical window, they can also form stable SEI layers on LMA and Si anode surfaces to enable their long-term cycling stability. The ultrathin SEI layer formed on a Gr anode can also improve the safety and high-rate operation of conventional LIBs. In this paper, we give a brief summary of our recent work on LHCEs, including their design…

Exhaled human breath analysis is a very promising field of research work having great potential for diagnosis of diseases in non-invasive way. Breath analysis has attracted huge attention in the field of medical diagnosis and disease monitoring in the last two decades. VOCs/gases (Volatile Organic Compounds) in exhaled breath bear the finger-prints of metabolic and biophysical processes going on in human body. It’s a non-invasive, fast, non-hazardous, cost effective, and point of care process for disease state monitoring and environmental exposure assessment in human beings. Some VOCs/gases in exhaled breath are bio-markers of different diseases and their presence in excess amount is indicative of un-healthiness. Breath analysis has the potential for early detection of diseases. However, it is still underused and commercial device is yet not available owing to multiferrious challenges. This review is intended to provide an overview of major biomarkers (VOCs/gases) present in exhaled breath, importance of their analysis towards disease monitoring, analytical techniques involved,…

In the last three decades, a lot of scientific research has been carried out in the field of Carbon nanomaterials all over the world due to their significant electronic, optical, mechanical, chemical and thermal properties. The zero, one, two and three dimensional Carbon nanomaterials (i.e. fullerenes, Carbon nanotubes, Graphene, Carbon quantum dots, Carbon Nanohorns, Nanodiamonds, Carbon Nanofibres and Carbon black) have exhibited such inherent features that can be easily exploited in the development of advanced technology for sensing applications. The employment of nanomaterials within sensors has paved new way and opportunities for the detection of analytes or target molecules. Carbon nanomaterials based electrochemical biosensors have reported biocompatibility, better sensitivity, better selectivity and lower limits of detection to detect a wide range of chemical to biological molecules. In this paper, a comprehensive review has been made to cover recent developments in the field of Carbon based nanomaterials as electrochemical biosensors. The characteristic features of a…

Recently, the field of CO 2 electrolysis has experienced rapid scientific and technological progress. This review focuses specifically on the electrochemical conversion of CO 2 into carbon monoxide (CO), an important “building block” for the chemicals industry. CO 2 electrolysis technologies offer potentially carbon-neutral routes for the production of specialty and commodity chemicals. Many different technologies are actively being pursued. Electrochemical CO 2 reduction from aqueous solutions stems from the success of alkaline and polymer electrolyte membrane electrolyzers for water electrolysis and uses performance metrics established within the field of aqueous electrochemistry. High-temperature CO 2 electrolysis systems rely heavily on experience gained from developing molten carbonate and solid oxide fuel cells, where device performance is evaluated using very different parameters, commonly employed in solid-state electrochemistry. In this review, state-of-the-art low-temperature, molten carbonate, and solid oxide electrolyzers for the production of CO are reviewed, followed…

Nanosensors are sensing devices with at least one of their sensing dimensions being up to100 nm. In the field of nanotechnology, nanosensors are instrumental for (a) detecting physical and chemical changes, (b) monitoring biomolecules and biochemical changes in cells, and (c) measuring toxic and polluting materials presented in the industry and environment. Nanosensors can be classified according to their energy source, structure and applications. The nanostructured materials used in manufacturing of nanosensors are such as: nanoscale wires (capability of high detection sensitivity), carbon nanotubes (very high surface area and high electron conductivity), thin films, metal and metal oxides nanoparticles, polymer and biomaterials. The aim of this review is to provide an overview of all classifications of nanosensors, showing the characteristcs and functioning mechanisms among the various categories.

Understanding the diffusion of lithium ions in electrode materials for lithium ion batteries is of great importance for their knowledge-based optimization and development of novel materials and cell designs. The galvanostatic intermittent titration technique (GITT) is widely applied in battery research to study the diffusion of lithium in anode and cathode materials depending on the degree of lithiation. While transport properties of electrode materials at high and ambient temperatures are largely available, low temperature diffusion and rate coefficients are hardly reported in the literature and vary by orders of magnitude for identical active materials. Herein, we demonstrate and discuss several challenges and pitfalls in the application and evaluation of GITT measurements for determining the effective chemical lithium ion diffusion coefficient in lithium insertion electrodes, which become especially important at low temperature. This includes theoretical considerations and an experimental analysis of the promising cathode material LiNi0.5Co0.2Mn0.3O2 (NCM523) in the wide…

In liquid electrolyte-type lithium-ion batteries, Nickel-rich NCM (Li1+x (Ni1−y−z Co y Mnz)1−x O2) as cathode active material allows for high discharge capacities and good material utilization, while solid-state batteries perform worse despite the past efforts in improving solid electrolyte conductivity and stability. In this work, we identify major reasons for this discrepancy by investigating the lithium transport kinetics in NCM-811 as typical Ni-rich material. During the first charge of battery half-cells, cracks form and are filled by the liquid electrolyte distributing inside the secondary particles of NCM. This drastically improves both the lithium chemical diffusion and charge transfer kinetics by increasing the electrochemically active surface area and reducing the effective particle size. Solid-state batteries are not affected by these cracks because of the mechanical rigidity of solid electrolytes. Hence, secondary particle cracking improves the initial charge and discharge kinetics of NCM in liquid electrolytes, while it degrades the corresponding kinetics in solid…

Portable fluorescence sensors have been developed for biochemical detection, water quality monitoring, biomedical sensing, and many other applications. With help of advancement in modern electronics, conventional fluorescence-based instrumentations are now integrated into portable sensing devices for remote and resource-limited settings. In this work, fluorescence sensing technology is introduced and different applications of portable fluorescence sensors and their characteristics are reviewed. Current issues, technological challenges, and future direction of the portable fluorescence sensor development are discussed. The goal is to provide a comprehensive survey on the recent advancements in optics, semiconductors, smartphones, and many other manufacturing technologies that increased the portability, miniaturization, and sensitivity of portable fluorescence sensor devices.

A study of the Solid Electrolyte Interphase (SEI) on hard-carbon (HC) electrodes in sodium half-cells is presented. Electrochemical performances over > 100 cycles were compared with two different salts (NaPF6, NaTFSI) and two different electrolyte additives (FEC, DMCF) in a mixture of EC and DMC solvents. The best electrochemical performances were observed with NaPF6 salt in conjunction with 3% FEC. The DMCF additive had a detrimental effect in all electrolyte combinations. The chemical characterization of the SEI was carried out by X-ray Photoelectron Spectroscopy (XPS) and showed that the best electrochemical behavior was related to an SEI composition based on sodium ethylene dicarbonate and NaF, whereas poorer electrochemical performances were associated to either low NaF or high Na2CO3 content. The results reported herein provide an insight on the SEI chemistry on hard carbon electrodes in sodium cells after long-term cycling, as a complement to previous studies dealing with the first cycles.

Cancer is a dreadful disease with a high mortality rate, and it has become more and more prevalent worldwide. Early diagnosis, prognosis and treatment monitoring with robust and non-invasive tools will potentially be the future focus. Electrochemical biosensor can be a strong candidate for cancer theranostics owing to their advantage of ultra-sensitivity, high selectivity, low cost, quick readout, and simplicity. Furthermore, electrochemical biosensors are easier to be miniaturized and mass fabricated, which grant them a better fit for point-of-care applications. In this review, various electrochemical measurement methods, bioreceptor surface, signal generation and amplification, integration of electrochemical sensors in microfluidic chips were summarized. Especially, multiplexed and ratiometric electrochemical biosensor were emphasized in cancer biomarkers detection. Then, measurement and analysis of cancers based on electrochemical biosensors in molecular level (DNA, RNA, and protein), organelle level (exosomes), cell level (cell counting, phenotypic and metabolism analysis, drug…

The recent advances in wearable electronics and intelligent human-machine interface systems have garnered great interests in electromechanical sensors, which can measure and quantify physical stimuli. Among different types of electromechanical sensors, piezoresistive sensors have been extensively investigated due to the excellent sensitivity, simple construction, and durability. Especially, there have been remarkable developments of flexible and stretchable piezoresistive sensors for wearable devices by investigating novel material/structural strategies to obtain highly sensitive piezoresistive sensors with skin-like flexibility. Here, we give a comprehensive overview of the recent progress in flexible and stretchable piezoresistive sensors and their applications. Based on the material composition and structural characteristics, the piezoresistive sensors are categorized into three types—conductive polymeric composite, porous conductive material, and architected conductive material. Subsequently, we have summarized their transduction mechanisms, fabrication processes, sensing…

The Lithium-ion battery (LIB) is an important technology for the present and future of energy storage, transport, and consumer electronics. However, many LIB types display a tendency to ignite or release gases. Although statistically rare, LIB fires pose hazards which are significantly different to other fire hazards in terms of initiation route, rate of spread, duration, toxicity, and suppression. For the first time, this paper collects and analyses the safety challenges faced by LIB industries across sectors, and compares them to the research contributions found in all the review papers in the field. The comparison identifies knowledge gaps and opportunities going forward. Industry and research efforts agree on the importance of understanding thermal runaway at the component and cell scales, and on the importance of developing prevention technologies. But much less research attention has been given to safety at the module and pack scales, or to other fire protection layers, such as compartmentation, detection or suppression. In order to close the gaps found and accelerate the…

Cell voltages at high current densities (HCD) of an operating proton-exchange membrane fuel cell (PEMFC) cathode suffer from losses due to the local-O2 and bulk-H+ transport resistances in the catalyst layer. Particularly, the microstructure of high surface area carbon (HSC) support upon which both the platinum catalyst and ionomer are dispersed play a pivotal role in controlling the reactant transport to the active site in the catalyst layer. In this study, we perform a systematic analysis of the underlying microstructure of platinum-cobalt catalyst dispersed on various HSC supports in terms of their surface area and pore-size distribution. The carbon microstructure was found to strongly influence the PtCo nanoparticle dispersion, catalyst layer ionomer distribution and transport losses governing the performance at HCD. Catalyst layer electrochemical diagnostics carried out to quantify local-O2 transport resistance and bulk-H+ transport resistance in the cathode were found to be directly correlated to the micropore (<2 nm) and macropore (>8 nm) surface areas of the carbon support,…

Porous electrodes are prevalent in electrochemical devices. Electrochemical impedance spectroscopy (EIS) is widely used as a noninvasive, in situ characterization tool to investigate multi-phase (electronic, ionic, gaseous) transport and coupling interfacial reactions in porous electrodes. Interpretation of EIS data needs model and fitting which largely determine the type and amount of information that could possibly be obtained, and thereby the efficacy of the EIS method. This review focuses on physics-based models, as such models, compared to electrical circuit models, are more fundamental in our understanding of the porous electrodes, hence more reliable and more informative. Readers can have a glimpse of the long history of porous electrode theory and in particular its impedance variants, acquaint themselves with the celebrated de Levie model and a general theoretical framework, retrace the journey of extending the de Levie model in three directions, namely, incorporating new physico-chemical processes, treating new structural effects, and considering high orders. Afterwards, a…

In the search for active Lithium-ion battery materials with ever-increasing energy density, the limits of conventional auxiliary materials, such as binders and conducting additives are being tested. Binders adhere to active substances and current collectors, yielding an interconnected electrode structure that ensures mechanical integrity during the (de-)lithiation process. Even though the battery binder only accounts for a fraction of battery weight and cost, it is a bottleneck technology in the deployment of high energy density active materials that experience significant volume variation and side-reactions. This review paper discusses research on alternative binders derived from conducting polymers (CPs). The use of CPs in binders enables mechanically flexible electronic contacts with the active material with the goal of accommodating larger volume changes within the electrode. Following a summary of the reasoning behind the use of CP-based binders, their rational design is reviewed, including novel composite syntheses and chemical modifications. A new class of multifunctional…

The downtime of industrial machines, engines, or heavy equipment can lead to a direct loss of revenue. Accurate prediction of such failures using sensor data can prevent or reduce the downtime. With the availability of Internet of Things (IoT) technologies, it is possible to acquire the sensor data in real-time. Machine Learning and Deep Learning (DL) algorithms can then be used to predict the part and equipment failures, given enough historical data. DL algorithms have shown significant advances in problems where progress has eluded the practitioners and researchers for several decades. This paper reviews the DL algorithms used for predictive maintenance and presents a case study of engine failure prediction. We also discuss the current use of sensors in the industry and future opportunities for electrochemical sensors in predictive maintenance.

Rechargeable batteries are becoming increasingly important for our daily life due to their strong capability of efficiently storing electric energy under chemical form. The replacement of conventional liquid electrolytes with polymer electrolytes (PEs) has been deemed as one of the most viable solutions towards safer and higher energy density electrochemical energy storage systems which are coveted for e-mobility applications (e.g., electric vehicles, EVs). In recent years, the introduction of inorganic materials into PEs has captured escalating interest, aiming at harmonizing advantages from both organic and inorganic phases. In this review, we present the progress and recent advances in PEs containing nano-sized inorganic materials, with due attention paid to the role of inorganic phases on the physical and chemical properties of the electrolytes. The paradigm shift from composite polymer electrolytes (CPEs, obtained by physical blending) to hybrid polymer electrolytes (HPEs, obtained by chemical grafting) is highlighted and the possible improvement and future directions in CPEs…

The emergence of textile-based wearable sensors as light-weight portable devices to monitor desired parameters, has recently gained much interest and has led to the development of flexible electronics on non-rigid substrates. The flexible biosensors may result in improved sports performance, to monitor the desired bodies for injuries, improved clinical diagnostics and monitor biological molecules and ions in biological fluids such as saliva, sweat. In addition, they could help users with different types of disorders such as blindness. In this context, new composite and nanomaterials have been found to be promising candidates to obtain improved performance of the textile based wearable devices and to optimize the structures for intimate contact with the skin for better functionality. This review aims to provide the most recent cutting-edge information on emergence, fabrication, materials, and applications of chemical and physical flexible and stretchable textile-based (bio)sensors. Besides this, we discusss the recent key innovations and applications of textile-based sensors in…

Single crystal LiNi 0.5 Mn 0.3 Co 0.2 O 2 (SC532), LiNi 0.6 Mn 0.2 Co 0.2 O 2 (SC622) and LiNi 0.8 Mn 0.1 Co 0.1 O 2 (SC811) electrodes were retrieved from heavily cycled commercial-grade pouch cells at 4.3 V for cross-section scanning electron microscopy (SEM). SEM images indicated the single crystals showed very little microcracking, thought by many researchers to be one of the main reasons for cell degradation when polycrystalline materials are used. SEM images of electrodes from heavily cycled cells were compared to those from fresh cells which showed little visual difference. Parallel microcracks within very few single crystal particles were observed for both fresh and heavily cycled materials and are thought to be caused during the electrode calendaring process. It is believed by the authors that single crystal materials are highly promising positive electrode materials for high energy density and long cycle life lithium-ion cells.

Most cathode materials for lithium-ion batteries exhibit a low electronic conductivity. Hence, a significant amount of conductive graphitic additives are introduced during electrode production. The mechanical stability and electronic connection of the electrode is enhanced by a mixed phase formed by the carbon and binder materials. However, this mixed phase, the carbon binder domain (CBD), hinders the transport of lithium ions through the electrolyte pore network. Thus, reducing the performance at higher currents. In this work we combine microstructure resolved simulations with impedance measurements on symmetrical cells to identify the influence of the CBD distribution. Microstructures of NMC622 electrodes are obtained through synchrotron X-ray tomography. Resolving the CBD using tomography techniques is challenging. Therefore, three different CBD distributions are incorporated via a structure generator. We present results of microstructure resolved impedance spectroscopy and lithiation simulations, which reproduce the experimental results of impedance spectroscopy and…

Electrochemical Impedance Spectroscopy (EIS) in the past few years has been used to design gas sensors. EIS based gas sensing has been considered as an ultra-sensitive technique to identify and measure different toxic gases. Their sensing performance has been superior when compared to other conventional techniques. Impedance makes it possible to investigate the finer changes occurring on the surface of sensing layers leading to the identification of the target gases such as H 2 S. The measurements are carried out by scanning the electrode surface with a mixture of frequencies from 1 Hz to 10 MHz and recording the response as Nyquist and Bode plots. From these plots, the results can be used to elucidate the electrochemical phenomena. The acquired impedance data can be fitted into equivalent circuits and this is further modeled to obtain information about the interfacial phenomena like grain bulk resistance, grain boundary resistance, interface between electrode and sensing film resistance. These phenomena support the sensing of toxic gases from ppm - ppb level. This article focuses…

Lithium-ion batteries (LiB) offer a low-cost, long cycle-life and high energy density solution to the automotive industry. There is a growing need of fast charging batteries for commercial application. However, under certain conditions of high currents and/or low temperatures, the chance for Li plating increases. If the anode surface potential falls below 0 V vs Li/Li + , the formation of metallic Li is thermodynamically feasible. Therefore, determination of accurate Li plating curve is crucial in estimating the boundary conditions for battery operation without compromising life and safety. There are various electrochemical and analytical methods that are employed in deducing the Li plating boundary of the Li-ion batteries. The present paper reviews the common test methods and analysis that are currently utilized in Li plating determination. Knowledge gaps are identified, and recommendations are made for the future development in the determination and verification of Li plating curve in terms of modeling and analysis.

The properties of porous transport layers (PTL) in electrolysis devices and their effects on cell performance have been studied extensively in recent literature. This paper provides a detailed analysis with regards to the transport in the catalyst layer (CL). The work demonstrated that the catalyst loading affects the sensitivity of electrolysis performance to PTL properties, particularly those of the PTL surface in contact with the CL. It was demonstrated that upon reducing catalyst loading, PTL properties had an increased effect on the performance of PEMWE cells. While we observed mild performance variations among PTLs when using a high anode catalyst loading, strong correlations between PTL surface properties and cell performance existed at a low catalyst loading. PTL properties affected performance by influencing the in-plane conductivity and permeability of the CL. The variation of apparent exchange current density and apparent CL bubble coverage with the stoichiometric flow rate was studied at low anode feed rates. This led to the emergence of a PTL grain size effect on…

Metal-organic frameworks, a class of highly crystalline porous materials, have gained intense research interest in material science in the last decade due to its intriguing chemistry and unique properties which lead to diverse applications. There are different methods for the development of MOF thin film in lab scale and its fabrication in electronic devices. However, the harsh reaction conditions, prolonged synthesis time, complex experimental setup etc. limit its application. Here, the electrochemical synthesis offers the advantages of mild reaction conditions, real time tuning of applied potential, short reaction time etc. which make the selective deposition of MOF on various conducting substrates facile. In this review, we focus on the direct electrochemical synthesis of MOF with emphasis on anodic and cathodic electrodeposition. The two different synthetic methods are explained in detail with a detailed review on its progress since its development. The electrosynthesis of MOF is still in its infancy stage and therefore the challenges and future perspectives associated with it…

Solid state gas sensors are a core enabling technology to a range of measurement applications including industrial, safety, and environmental monitoring. The technology associated with solid-state gas sensors has evolved in recent years with advances in materials, and improvements in processing and miniaturization. In this review, we examine the state-of-the-art of solid state gas sensors with the goal of understanding the core technology and approaches, various sensor design methods to provide targeted functionality, and future prospects in the field. The structure, detection mechanism, and sensing properties of several types of solid state gas sensors will be discussed. In particular, electrochemical cells (solid and liquid), impedance/resistance based sensors (metal oxide, polymer, and carbon based structures), and mechanical sensing structures (resonators, cantilevers, and acoustic wave devices) as well as sensor arrays and supporting technologies, are described. Development areas for this field includes increased control of material properties for improved sensor response and…

With higher nature abundance and lower production cost of sodium-based materials compared to lithium-based ones, sodium batteries have been arising as one of the most promising energy storage systems serving as complementary power sources to the popular lithium-ion batteries. Replacing conventional liquid electrolytes containing flammable liquid solvents with polymer electrolytes (PEs) empowers sodium batteries with inherently enhanced safety at a low expense of processability. In this contribution, we present a comprehensive overview on the research progresses and advances in the PE-based sodium batteries, including three main categories of PEs, i.e., solid polymer electrolytes (SPEs), composite solid polymer electrolytes (CSPEs), and plasticized/gel polymer electrolytes (PPEs/GPEs). The energy densities of sodium batteries at cell level are estimated and compared with their lithium counterparts. The research development of PE-based sodium batteries is scrutinized and the remaining challenges and possible solutions are intensively discussed. The purpose of the present work is not…

We present an electrochemical aging model with solid electrolyte interphase (SEI) formation, SEI re-formation due to cracking of the layer during graphite expansion, lithium plating when the potential of the negative electrode becomes negative vs Li/Li+, and subsequent lithium stripping once the potential becomes positive again. The model considers the transition from an early stage, linear to a later stage, nonlinear capacity fade. While SEI re-/formation define linear aging, the onset and slope of nonlinear aging is simulated based on the ratio of reversibly and irreversibly plated lithium. With ongoing aging, more lithium is plated irreversibly so that less lithium is stripped. The simulation data agree very well with experimental data on commercial 18 650-type lithium-nickel-cobalt-manganese-oxide vs graphite (NCM/C) cells.

Electrochemical noise (EN) can be used in situ to investigate corrosion processes and to detect and monitor the corrosion of metallic materials. EN data are largely influenced by the measurement mode, the surface area of the working electrodes, the electrolyte resistance, and the symmetry of the electrode system. Herein, the advantages and limitations of electrochemical kinetics, equivalent circuit, and shot noise methods for quantifying corrosion rates with EN are discussed.

The research on aqueous zinc ion batteries (AZIB) is getting more attention as the energy transition continues to develop and the need for inexpensive and safe stationary storage batteries is growing. As the detailed reaction mechanisms are not conclusively revealed, we want to take an alternative approach to investigate the importance of pH value changes during cycling. By adding a pH-indicator to the electrolyte (2 M ZnSO 4 + 0.1 M MnSO 4 ), the local pH-value change during operation is visualized in operando. The overall pH value was found to increase during cycling whereas a major temporary pH drop in close proximity of the manganese dioxide electrode surface occurs. Additionally, this pH value change was quantified locally by in operando measurements with a pH micro electrode. Different electrolyte compositions with additives (sodium dodecyl sulfate (SDS), sulfuric acid (H 2 SO 4 )) and operation voltages were tested. The pH-potential-diagrams of manganese and zinc reveal pH value and potential limits, leading to active material dissolution at lower pH values and oxygen gas…

A critical review of classical and improved electrodes, electrocatalysts and reactors is provided. The principles governing the selection of electrochemical flow reactor or progression of a particular design for laboratory or pilot scale are reviewed integrating the principles of electrochemistry and electrochemical engineering with practical aspects. The required performance, ease of assembly, maintenance schedule and scale-up plans must be incorporated. Reactor designs can be enhanced by decorating their surfaces with nanostructured electrocatalysts. The simple parallel plate geometry design, often in modular, filter-press format, occupies a prominent position, both in the laboratory and in industry and may incorporates porous, 3D or structured electrode surfaces and bipolar electrical connections considering the reaction environment, especially potential- and current-distributions, uniformity of flow, mass transport rates, electrode activity, side reactions and current leakage. Specialised electrode geometries include capillary gap and thin film cells, rotating cylinder…

While various techniques have been developed to address the safety issues in lithium-ion batteries, there remain unknown mechanisms that induce hazards, leaving challenges in developing reliable lithium-ion systems. In this manuscript, an unpredictable hazard originated from the dissolution of transition metal ions from cathodes and their deposition on anodes is presented. The cathodes in currently commercialized lithium-ion batteries contain transition metal ions, which might dissolve in electrolytes, transport through separators and deposit on anodes. When the deposition proceeds in the form of metals, the deposited transition metals might induce a hazard due to the lithium dendrite growth on them. Since the electrolyte decomposition usually accompanies the transition metal deposition with a possibility that the electrolyte decomposition products might cover the deposited metals, the induced hazard becomes unpredictable. The typical mechanisms involved in the dissolution and deposition of transition metal ions and the possible strategies to eliminate the unpredictable hazard…

All solid-state lithium batteries (ASSLBs) employing inorganic solid electrolytes or solid polymer electrolytes are attracting increasing interests for electrochemical energy storage devices due to their advantages of high energy density, high safety, wide operating temperature range and long cycle life. However, the large interfacial resistance originated from the insufficient solid-solid contact at electrolyte/electrode interface hinders the development of ASSLBs. In addition, the interfacial stability and compatibility also greatly affect the electrochemical performance of batteries. To realize the ASSLB’s application requires significant research in solid electrolyte materials and solid electrolyte/electrode interfaces. This review summarizes the research and development in solid electrolyte materials and the interfaces of solid electrolyte/electrode, paying special attention to the challenges and progress for the studies of interface issues in ASSLBs. Based on the overview, we attempt to propose approaches to the issue by interface engineering and prospective developments of…

Professor Michel Armand is one of the world's leading scientists in the R&D of modern energy storage systems.His scientific works have been devoted to the concepts and technologies of today's batteries, in particular, mastering research on electrodes and electrolytes.With respect to innovative discoveries, Michel had several scientific breakthroughs from the description of the solidsolution electrode and rocking-chair battery to the applications of novel materials utilized in all-solid-state batteries (SSBs); these refer to Li-ion, Na-ion, Li-S, and Li-air cells.At a young age, he formalized the concept of electrochemical intercalation and fabricated the first SSB with sodium-intercalated graphite as the electrode in 1972.Subsequently, he led the use of solid polymer electrolytes and developed lithium-metal-polymer batteries with vanadium oxide as the cathode in 1978.Michel successfully conducted research in new salts topics based on delocalized anions of the sulfonimide family in 1986; his research areas included 1) organic electrode materials, i.e., innovations in redox-active…

In order to understand the lithium-ion battery (LIB) failing behavior and to prevent failures and their consequences, different LIB safety tests, also called abuse tests, have been developed. This paper focuses on thermal runway (TR) triggered by overtemperature, overcharge and nail-penetration. It shows the setup and the results of the three different TR triggers on two different cell types in a custom-made TR reactor. The investigated cell types are state-of-the-art automotive pouch and hard case cells. The results are discussed in three main categories: thermal behavior, vent gas production and vent gas composition. The results and findings are supposed to be valuable for battery pack designer, car manufacturer and testing institutions for the development of future battery testing facilities and regulations.

In this study, on-line mass spectrometry is used to determine hydrogen permeation during proton exchange membrane water electrolyzer (PEM-WE) operation for a wide range of current densities (0–6 A cm −2 ) and operating pressures (1–30 bar, differential pressure). H 2 permeation measurements with a permeation cell setup, i.e., without applying a current, show a linear correlation between permeation rate and H 2 partial pressure, indicating diffusion as the main crossover mechanism. Measurements with full membrane electrode assemblies (MEAs) during PEM-WE operation reveal a significant increase of the gas permeation rate at high current densities, by up to ≈20-fold at 1 bar H 2 and up to ≈1.2-fold at 30 bar H 2 (Nafion ® 212 or Nafion ® 117 membrane; Ir-black (anode) and Pt/C (cathode)). Recently, H 2 super-saturation of the ionomer phase in the cathode catalyst layer was shown to be the reason for this increase, and we discuss the impact of this effect for different electrode compositions and operating conditions. Finally, the determined H 2 permeation rates and electrolyzer…

The determination of hydrogen peroxide (H 2 O 2 ) plays a crucial role in many industrial applications as well as clinical diagnoses. Electrochemical sensing techniques can provide a rapid, accurate, and simple approach to determine the level of hydrogen peroxide accurately. Recently, reduced graphene oxide (rGO) has been employed extensively to develop amperometric sensors for sensitive and selective detection of H 2 O 2 because of its good catalytic activity, mass scalability, and cost-effectiveness. During the past decade, various reduction methods have been used to produce rGO for electrochemical sensing applications. Besides, these electrodes have been modified with functional materials to improve the response of the sensors. Depending on the used materials, characteristics and sensitivity of the sensors varied a lot. Also, the production method of rGO affects the performance of the electrochemical sensor and needs to be taken into account to correlate the results from the sensor with the physical and chemical properties of the sensing material. This article provides an…

Lithium ion batteries using liquid electrolytes often face challenges of safety issues. Polymer electrolytes can effectively solve this problem. Traditional preparation of polymer electrolytes is solution-casting method, which is complicated in practical application. Simultaneously, this ex-situ polymer electrolytes prepared by conventional method exhibits poor interfacial contact with electrodes. Fortunately, the emerging in-situ polymerization of solid state polymer electrolytes simplifies the preparation and forms an integrated interface for better interfacial compatibility in solid state lithium batteries. It is certain that solid state lithium batteries via in-situ polymerization exhibit various functionality: (1) forming integrated interface to enhance interfacial compatibility; (2) inhibiting the dissolution of transition metal ions; (3) suppressing the growth of lithium dendrites; (4) Improving the cycle performance of silicon anodes; (5) inhibiting the shuttling effect of polysulfides; (6) promoting battery performance of post-lithium batteries. Therefore, the review mainly…

Human breath investigation offers a non-invasive and quick strategy for recognizing different volatile organic compounds (VOCs) that are markers for various diseases. Scientists have shown that breath acetone is a successful biomarker of Type 2 diabetes which is the most common type of diabetes. The generation of acetone is a consequence of the body processing fats as an alternative of glucose to produce energy. Thus, detection of breath acetone can be a rapid, viable, and patient compliant alternative to the conventional methods of blood glucose determination. To achieve this goal, metal oxide nanostructures with various shapes through different synthesis routes in the nanometer scale, can be used. Owing to its properties such as high surface-to-volume ratios and subsequently large number of surface sites exposed to acetone gas, metal oxide nanostructures facilitate a well-built gas-sensing layer interaction and consequently compared to conventional materials, present a higher sensitivity. This work, presents the progress in metal oxides nanostructures (semiconductor nanomaterials)…

In this study, we synthesized hierarchical CuO nanoleaves in large-quantity via the hydrothermal method. We employed different techniques to characterize the morphological, structural, optical properties of the as-prepared hierarchical CuO nanoleaves sample. An electrochemical based nonenzymatic glucose biosensor was fabricated using engineered hierarchical CuO nanoleaves. The electrochemical behavior of fabricated biosensor towards glucose was analyzed with cyclic voltammetry (CV) and amperometry (i–t) techniques. Owing to the high electroactive surface area, hierarchical CuO nanoleaves based nonenzymatic biosensor electrode shows enhanced electrochemical catalytic behavior for glucose electro-oxidation in 100 mM sodium hydroxide (NaOH) electrolyte. The nonenzymatic biosensor displays a high sensitivity (1467.32 μ A/(mM cm 2 )), linear range (0.005–5.89 mM), and detection limit of 12 nM (S/N = 3). Moreover, biosensor displayed good selectivity, reproducibility, repeatability, and stability at room temperature over three-week storage period. Further, as-fabricated nonenzymatic…

Additive manufacturing technologies open the way to the direct-integration of electronics and solid-state battery within the final 3D object. Here, a 3D printable polyethylene oxide/lithium bis(trifluoromethanesulfonyl)imide (PEO/LiTFSI) filament (2.18 × 10 −3 S cm −1 at 90 °C) optimized to be used as solid polymer electrolyte in a lithium-ion battery is produced to feed a fused deposition modeling (FDM) 3D-printer. Due to its relatively poor mechanical properties compared to classical polymer filament such as polylactic acid (PLA), deep modifications of the 3D-printer were implemented in order to facilitate its printability. The solid polymer electrolyte thermal, structural, morphological, mechanical and electrical characterization is reported. Interestingly, using three different electrochemical impedance spectroscopy sample holders (lateral, sandwich and interdigitated-comb), we demonstrate that conductivity values differs for a same sample, highlighting the PEO chains orientation effect on the conductivity measurements.

Soil monitoring is emerging as a key factor to manage smart farming which has been recommended to have economical food safety and security. Among various development for example internet of things assisted farming, electrochemical sensing system are getting popularity via detecting one or multiple soil component effectively, efficiently, and selectively for soil quality assessment remotely via data sharing and site of location just like point-of-care soil heath care. Considering scenarios, this perspective is designed to describe state-of-the art electrochemical sensing technology developed for soil quality. The associated challenges, possible alternatives, and potential prospects are also discussed in this perspective.

Globally, farmers are seeking advanced precision technology to help transform their practices into a more sustainable and productive agri-tech process. Accurate and real-time soil data has become one of the most valuable resources among farmers. Real-time soil sensor data can be exploited in manners that increase farm production and profit, maintain and increase product quality, promote food security, and ensure environmental protection. Researchers have already attempted to develop real-time in situ soil nutrient sensors based on optical and electrochemical techniques. Of these sensor systems, only a few of them are commercially available for monitoring. In this review, we present both available sensors and sensors under research in agriculture. Then briefly discuss both advantages and challenges to overcome in order to produce systems that deliver real-time quality soil information. Optical and electrochemical sensors are becoming less expensive to manufacture and can provide results that are comparable to laboratory soil analysis. Based on the literature presented here, there…

More powerful, durable, safer, greener and cheaper batteries are needed to fulfil the compelling requirements of automotive and grid applications. Addressing most of these requirements passes through the development of new-generation electrolytes able to overcome the issues of the state-of-the-art liquid ones, which are based on highly volatile and flammable organic solvents. At the same time, the quest for new electrolytes is strictly related to the attempt of replacing the graphite anode with lithium metal, so opening the way to full exploitation of new post-lithium chemistries, e.g. Li–air and Li–sulfur. Here, we critically review some original concepts which were recently proposed as routes for the development of liquid and quasi-solid electrolytes with improved performances in terms of safety, chemical and electrochemical stability, and capability to sustain high current densities. Attention will be devoted to the problem of lithium dendrites formation, and to the electrolyte families able to eliminate/control their development. Finally, the most promising research directions…

The development of smart polymer materials is reviewed and illustrated. Important examples of these polymers include conducting polymers, ionic gels, stimulus-response be used polymers, liquid crystalline polymers and piezoelectric materials, which have desirable properties for use in wearable sensors. This review outlines the mode of action in these types of smart polymers systems for utilisation as wearable sensors. Categories of wearable sensors are considered as tattoo-like designs, patch-like, textile-based, and contact lens-based sensors. The advantages and disadvantages of each sensor types are considered together with information on the typical performance. The research gap linking smart polymer materials to wearable sensors with integrated power systems is highlighted. Smart polymer systems may be used as part of a holistic approach to improve wearable devices and accelerate the integration of wearable sensors and power systems, particularly in health care.

The electrochemical polymerization of polyaniline (PANI) was studied using correlative measurements of electrochemistry and UV–vis spectroscopy, i.e., spectroelectrochemistry. The electropolymerization of PANI was performed in an acidic medium (1 M HCl) containing 0.1 M aniline with cyclic voltammetry (CV) in a potential window from −0.3 to 1 V and a 50 mV s−1scan rate. At the same time, UV–vis absorbance spectra in the wavelength range from 200 to 900 nm were measured for every 10 mV change in the CV. The CV results show the oxidation of the monomer at a high positive potential (0.9 V vs Ag), the continuous growth of the PANI film and the transformation between the three best-known forms of PANI redox in the potential range between −0.3 V and 1 V. In parallel, the spectroscopic study confirmed the formation of PANI oxidation. The spectroscopic results showed the formation of the final conductive PANI product (emeraldine salt) due to the absorbance of the formed charge carriers (polarons, bipolarons) during the polymerization. The correlative electrochemical/spectroscopy study gave…

Multi-walled carbon nanotubes (MWCNTs) without and with adsorbed silver nanoparticles (Ag-NPs), are used to detect acetone vapour. MWCNTs are grown on SiO2/Si substrates and silver (Ag) nanoparticles (NPs) are deposited onto some of these MWCNTs using electron beam evaporation method. The sensitivity of CNT based sensors (with and without NPs) increases with the concentration of acetone vapour (50 ppm to 800 ppm) while a substantial rise in sensitivity is obtained from MWCNTs with Ag NPs. Band diagrams of the MWCNTs, with and without NPs, are analyzed to understand the gas molecules adsorption phenomena. This study is the first to establish that such sensors can operate at 27 °C rather than the 180 °C–450 °C used elsewhere, thus offering significant advantages over existing methods. To investigate the sensors’ dependability, they’re exposed to three cycles of 50 ppm acetone gas. These tests show that the devices’ responses remain unchanged, indicating their reliability. The effects of humidity upon MWCNT acetone sensors within 100 ppm of acetone vapour are also studied and improved…

Alkaline exchange membrane fuel cells (AEMFCs) have advanced rapidly in recent years and now show improved potential to become a low-temperature fuel cell alternative to proton exchange membrane fuel cells. To date, performance and durability are still too low to meet the promised reductions in materials cost, especially demonstration of platinum group metal- and precious metal-free AEMFCs. U.S. Department of Energy technical milestones for the next ten years are laid out herein. These milestones focus on the major barriers to AEMFC viability, hastening economic competitiveness and application relevance. Standard test conditions will facilitate benchmarking of AEMFC catalysts and membranes.

Wearable sensors are becoming an important tool for healthcare monitoring as they can provide continuous monitoring of clinically important biomarkers released in the biofluids such as sweat, saliva, tears, urine and interstitial fluids (ISF). Development of smart sensing technologies for stress detection in daily life is find applications in various field including healthcare, defence and sports industries. Although different modalities for stress detection are performed in the clinical laboratories, the measurement of hormone release from glands of the endocrine system is receiving wide attention. Cortisol is considered as a biomarker of stress as the levels are spike in response to stressors. Although most of the cortisol released from adrenaline glands bound by corticosteroid-binding globulin (CBG), active form of free cortisol is also appearing in the biofluids (sweat, saliva, urine, tear, and ISF). Electrochemical biosensors, due to their relative small farm factors and sensitivity are focused for developing wearable biosensors for non-invasive monitoring of biochemical…