Work on solid electrolytes for rechargeable lithium-based batteries is motivated by the potential benefits of lithium-metal anodes for a variety of applications, including electric vehicles. Dendrite formation has been the key challenge preventing commercialization of rechargeable lithium-metal batteries, so establishing, validating, and improving the dendrite resistance of electrolytes is a key enabler of progress in the field. Typical symmetric cycling tests of Li-Li cells introduce operational and theoretical limitations which compromise the data produced and the conclusions which can be drawn from such testing. A high-throughput technique for unidirectional critical current density testing is presented which has allowed the development of a solid electrolyte capable of withstanding current densities of at least 300 mA cm−2. The theoretical and empirical basis for this testing methodology is outlined, results are presented and analyzed, and best practices for critical current density testing of solid electrolyte materials are proposed.
The Electrochemical Society (ECS) was founded in 1902 to advance the theory and practice at the forefront of electrochemical and solid state science and technology, and allied subjects.
ISSN: 1945-7111
JES is the flagship journal of The Electrochemical Society. Published continuously from 1902 to the present, JES remains one of the most highly-cited journals in electrochemistry and solid-state science and technology.
Danielle M. Gendron et al 2025 J. Electrochem. Soc. 172 020511
Eniko S. Zsoldos et al 2024 J. Electrochem. Soc. 171 080527
Lithium iron phosphate (LFP) battery cells are ubiquitous in electric vehicles and stationary energy storage because they are cheap and have a long lifetime. This work compares LFP/graphite pouch cells undergoing charge-discharge cycles over five state of charge (SOC) windows (0%–25%, 0%–60%, 0%–80%, 0%–100%, and 75%–100%). Cycling LFP cells across a lower average SOC results in less capacity fade than cycling across a higher average SOC, regardless of depth of discharge. The primary capacity fade mechanism is lithium inventory loss due to: lithiated graphite reactivity with electrolyte, which increases incrementally with SOC, and lithium alkoxide species causing iron dissolution and deposition on the negative electrode at high SOC which further accelerates lithium inventory loss. Our results show that even low voltage LFP systems (3.65 V) have a tradeoff between average SOC and lifetime. Operating LFP cells at lower average SOC can extend their lifetime substantially in both EV and grid storage applications.
Peter Keil et al 2016 J. Electrochem. Soc. 163 A1872
In this study, the calendar aging of lithium-ion batteries is investigated at different temperatures for 16 states of charge (SoCs) from 0 to 100%. Three types of 18650 lithium-ion cells, containing different cathode materials, have been examined. Our study demonstrates that calendar aging does not increase steadily with the SoC. Instead, plateau regions, covering SoC intervals of more than 20%–30% of the cell capacity, are observed wherein the capacity fade is similar. Differential voltage analyses confirm that the capacity fade is mainly caused by a shift in the electrode balancing. Furthermore, our study reveals the high impact of the graphite electrode on calendar aging. Lower anode potentials, which aggravate electrolyte reduction and thus promote solid electrolyte interphase growth, have been identified as the main driver of capacity fade during storage. In the high SoC regime where the graphite anode is lithiated more than 50%, the low anode potential accelerates the loss of cyclable lithium, which in turn distorts the electrode balancing. Aging mechanisms induced by high cell potential, such as electrolyte oxidation or transition-metal dissolution, seem to play only a minor role. To maximize battery life, high storage SoCs corresponding to low anode potential should be avoided.
George E. Blomgren 2017 J. Electrochem. Soc. 164 A5019
This year, the battery industry celebrates the 25th anniversary of the introduction of the lithium ion rechargeable battery by Sony Corporation. The discovery of the system dates back to earlier work by Asahi Kasei in Japan, which used a combination of lower temperature carbons for the negative electrode to prevent solvent degradation and lithium cobalt dioxide modified somewhat from Goodenough's earlier work. The development by Sony was carried out within a few years by bringing together technology in film coating from their magnetic tape division and electrochemical technology from their battery division. The past 25 years has shown rapid growth in the sales and in the benefits of lithium ion in comparison to all the earlier rechargeable battery systems. Recent work on new materials shows that there is a good likelihood that the lithium ion battery will continue to improve in cost, energy, safety and power capability and will be a formidable competitor for some years to come.
Manuel Ank et al 2023 J. Electrochem. Soc. 170 120536
Battery research depends upon up-to-date information on the cell characteristics found in current electric vehicles, which is exacerbated by the deployment of novel formats and architectures. This necessitates open access to cell characterization data. Therefore, this study examines the architecture and performance of first-generation Tesla 4680 cells in detail, both by electrical characterization and thermal investigations at cell-level and by disassembling one cell down to the material level including a three-electrode analysis. The cell teardown reveals the complex cell architecture with electrode disks of hexagonal symmetry as well as an electrode winding consisting of a double-sided and homogeneously coated cathode and anode, two separators and no mandrel. A solvent-free anode fabrication and coating process can be derived. Energy-dispersive X-ray spectroscopy as well as differential voltage, incremental capacity and three-electrode analysis confirm a NMC811 cathode and a pure graphite anode without silicon. On cell-level, energy densities of 622.4 Wh/L and 232.5 Wh/kg were determined while characteristic state-of-charge dependencies regarding resistance and impedance behavior are revealed using hybrid pulse power characterization and electrochemical impedance spectroscopy. A comparatively high surface temperature of ∼70 °C is observed when charging at 2C without active cooling. All measurement data of this characterization study are provided as open source.
Yuliya Preger et al 2020 J. Electrochem. Soc. 167 120532
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 LiFePO4 (LFP), LiNixCoyAl1−x−yO2 (NCA), and LiNixMnyCo1−x−yO2 (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 standard deviation for performance. All cycling files have been made publicly available at batteryarchive.org, a recently developed repository for visualization and comparison of battery data, to facilitate future experimental and modeling efforts.
Toby Bond et al 2024 J. Electrochem. Soc. 171 110514
As service lifetimes of electric vehicle (EV) and grid storage batteries continually improve, it has become increasingly important to understand how cells perform after extensive cycling. The multifaceted nature of degradation in Li-ion cells can lead to complex behavior that may be difficult for battery management systems or operators to model. Accurate characterization of heavily cycled cells is critical for developing accurate models, especially for cycle-intensive applications like second-life grid storage or vehicle-to-grid charging. In this study, we use operando synchrotron x-ray diffraction (SR-XRD) to characterize a commercially manufactured polycrystalline NMC622 pouch cell that was cycled for more than 2.5 years. Using spatially resolved synchrotron XRD, the complex kinetics and spatially heterogeneous behavior of such cells are mapped and characterized under both near-equilibrium and non-equilibrium conditions. The resulting data is complex and multifaceted, requiring a different approach to analysis and modelling than what has been used in the literature. To show how material selection can impact the extent of degradation, we compare the results from polycrystalline NMC622 cells to an extensively cycled single-crystal NMC532 cell with over 20,000 cycles—equivalent to a total EV traveled distance of approximately 8 million km (5 million miles) over six years.
Chang-Hui Chen et al 2020 J. Electrochem. Soc. 167 080534
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-SiOx 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 during lithiation. The 35 parameters are applied within a P2D model to show the fit to experimental validation LGM50 cell discharge and relaxation voltage profiles at room temperature. The accuracy and validity of the processes and the techniques in the determination of these parameters are discussed, including opportunities for further modelling and data analysis improvements.
Nagappan Ramaswamy et al 2025 J. Electrochem. Soc. 172 024501
Catalyst requirements for proton exchange membrane (PEM) fuel cells differ by applications. Commercial heavy-duty vehicle (HDV) applications consume more H2 fuel and demand higher durability than many others and the total cost of ownership (TCO) of the vehicle is largely related to the performance and durability of catalysts. This article is written to bridge the gap between the industrial requirements and academic activity for advanced cathode catalysts with an emphasis on durability. From a materials perspective, the underlying nature of the carbon support, Pt-alloy crystal structure, stability of the alloying element, cathode ionomer volume fraction, and catalyst-ionomer interface play a critical role in improving performance and durability. We provide our perspective on four major approaches, namely, mesoporous carbon supports, ordered PtCo intermetallic alloys, thrifting ionomer volume fraction, and shell-protection strategies that are currently being pursued. While each approach has its merits and demerits, their key developmental needs for future are highlighted.
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Claire Floras et al 2025 J. Electrochem. Soc. 172 020514
18650-sized cylindrical cells containing single crystal Li[Ni0.6Mn0.4Co0.0]O2, Li[Ni0.6Mn0.35Co0.05]O2, and Li[Ni0.6Mn0.3Co0.1]O2 positive electrodes along with artificial graphite negative electrodes were constructed to be balanced at 4.05 V. These cells were designed so that they would have only the single degradation mode of lithium inventory loss due to the solid-electrolyte interphase layer growth. Cells were cycled both at C/3 and C/20 over a wide temperature range from 20 to 100 °C in order to accelerate degradation processes at higher temperatures and more rapidly predict low-temperature behaviour. A low upper cutoff voltage of 4.0 V was selected to avoid electrolyte oxidation, and an electrolyte composition incorporating pure lithium bis(fluorosulfonyl)imide salt was chosen based on the temperature and voltage range of operation. A thorough post-cycling analysis was performed to verify the elimination of all degradation modes except inventory loss and minor impedance growth, which enabled the application of a simple square root time model to make accurate lifetime predictions. In addition, the capacity retention of these cells at elevated temperature is incredible, with the best cells retaining 87% capacity after 1400 C/3 cycles (one year) continuously at 85 °C.
Vanessa Scheck et al 2025 J. Electrochem. Soc. 172 039001
Vanessa Scheck et al 2025 J. Electrochem. Soc. 172 030504
Wetting of lithium-ion battery electrodes with electrolyte represents a challenge that is a mostly neglected aspect of electrode optimization. In the production of large-format cells, the rate of electrolyte wetting after filling is of particular importance, as wetting time often represents a significant bottleneck. This study employs a systematic, quantitative investigation of the wetting behavior of lithium-ion battery electrodes using a tensiometer and considering the Washburn equation. This approach facilitates a fundamental understanding of the wetting behavior of porous electrodes. To consider the influence of microstructural differences and intrinsic electrode properties, two water-based graphite anodes were employed, which exhibit the same microscopic properties but differ in their pore size distribution and binder system. The developed tensiometer method demonstrates that by employing the average pore radius obtained from pore size distribution measurements, it is feasible to consider separately microstructural and material-specific influencing factors of wetting. Further investigation revealed that one of the two electrodes exhibited superior wetting, whereby the improved wetting could be clearly attributed to the used binder system. The findings were verified by contact angle measurements of the individual binder system films, by a drop shape analyzer and by electrochemical impedance spectroscopy measurements in symmetrical pouch cells.
Mingming Zhao et al 2025 J. Electrochem. Soc. 172 032503
The titanium foam-based SnO2-Sb electrode has received more and more attention due to its high electrocatalytic activity, which is enabled by the unique porous structure of the titanium foam substrate. However, the electrode is constrained by the preparation method, exhibiting poor stability and a limited service life. An electrodeposition method was developed for preparing a high-efficiency, low-energy-consuming, and long-lasting foam titanium-based SnO2-Sb electrode, with the regulation of experimental parameters, including current density, counter electrode materials, and electrodeposition cycles. The results demonstrate that the prepared electrode coatings are well dispersed with improved grain refinement. The electrode surface exhibited multiple catalytically active sites and exhibited a low phenol decomposition potential (1.74 V). It achieved 98.39% phenol removal and 91.85% chemical oxygen demand removal within 180 min with high current efficiency (30.56%) and low reaction energy consumption of 0.13 kWh g−1. The electrode life is extended when electrodeposition is performed twice, resulting in an actual service life of 1130.20 h. In conclusion, this study presents a novel approach to the fabrication of foamed titanium-based SnO2-Sb electrodes with high performance for the electrochemical oxidation process.
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Highlights
The titanium foam-based SnO2-Sb electrode was prepared by the electrodeposition method.
Titanium foam was used as the electrode substrate.
The electrode has a service life of 1130.2 h.
The energy consumption for the degradation of phenol is 0.13 kWh g−1.
Alfred B. Anderson 2025 J. Electrochem. Soc. 172 036501
For many years since Gurney introduced quantum mechanics to electrochemistry, models and calculations assumed bonding and other properties at the electrochemical interface may be calculated with adequate accuracy at the potential of zero charge (PZC) and that the effect of potential lies solely in controlling the energy of the electron involved in the transfer, which comes from or goes to an external energy level. The energy of the electron is assigned to the Fermi energy, Ef, of the electrode for the particular potential being modeled. This is done in the Butler-Volmer theory as well as in several quantum mechanical modeling procedures that are introduced here. Though the PZC in fact changes as the identity, amount, and structures of molecules chemically bonded to the electrode are varied during calculations using these models, there is no control of the electrode potential in the calculations. The past two decades have seen the development of computer codes that can incorporate controlled incremental surface charging with polarizable electrolyte models that compensate it, resulting in zero net interface charge. Calculations using these codes provide accurate predictions of the potential-dependent energies of reactants and products, reversible potentials, and electron transfer activation energies.
Mariana Georges et al 2025 J. Electrochem. Soc. 172 031501
In this study, cyclic potentiodynamic polarization (CPP) tests and one-dimensional (1D) pit tests were performed to evaluate the corrosion behavior of stainless steel 316L at different temperatures and identify the critical conditions for repassivation. Downward potential scans for 1D pit samples were performed at different potential scan rates to precisely determine the repassivation potential at different pit depths. The outputs from 1D pit experiments were used to predict repassivation potentials (
) of three dimensional (3D) pits in bulk samples, assuming different pit geometries. Finally, these predictions were compared with the repassivation potentials obtained for bulk samples during CPP tests to verify the accuracy of predictions. This methodology provides a correlation between a controlled fundamental approach (1D pit tests) and a more practical and applied method (CPP tests on bulk samples, generating 3D pits). It also enhances the understanding of the variability in 
values obtained from the CPP technique, improving the reliability of this parameter.
Alfred B. Anderson 2025 J. Electrochem. Soc. 172 036501
For many years since Gurney introduced quantum mechanics to electrochemistry, models and calculations assumed bonding and other properties at the electrochemical interface may be calculated with adequate accuracy at the potential of zero charge (PZC) and that the effect of potential lies solely in controlling the energy of the electron involved in the transfer, which comes from or goes to an external energy level. The energy of the electron is assigned to the Fermi energy, Ef, of the electrode for the particular potential being modeled. This is done in the Butler-Volmer theory as well as in several quantum mechanical modeling procedures that are introduced here. Though the PZC in fact changes as the identity, amount, and structures of molecules chemically bonded to the electrode are varied during calculations using these models, there is no control of the electrode potential in the calculations. The past two decades have seen the development of computer codes that can incorporate controlled incremental surface charging with polarizable electrolyte models that compensate it, resulting in zero net interface charge. Calculations using these codes provide accurate predictions of the potential-dependent energies of reactants and products, reversible potentials, and electron transfer activation energies.
Yang Xiao et al 2025 J. Electrochem. Soc. 172 034504
Due to the advantages of environmental friendliness and high energy density, fuel cells have broad application prospects in many fields, such as automobiles, ships, aerospace, etc However, commercial applications of fuel cells also face challenges of durability and reliability, especially in shock and vibration environments. Here, the electrochemical and mechanical behaviours of fuel cells under vibration environments are described, and the effects of vibration and shock conditions on the electrochemical, mechanical, water and gas transport, and durability performance of fuel cells are systematically reviewed, involving the variation laws of assembly torque, sealing, relative slippage between cells, water and gas transport, electrical resistance, and membrane electrodes. In addition, the methods that can mitigate the effects of vibration on fuel cells in existing studies are summarised. Finally, discussions and perspectives on the research methods of fuel cell performance under vibration are presented. It is hoped that the review can provide a systematic comprehension and direction for vibration protection of fuel cells.
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Highlights
Vibration and shock have a negative impact on fuel cell performance in most cases.
Fuel cell performance degradation is affected by the coupling of multiple phenomena.
Specific vibration levels improve cell performance by facilitating water management.
Monitoring and vibration isolation/damping enable vibration protection of fuel cells.
Jake Kattelman et al 2025 J. Electrochem. Soc. 172 020528
Renewable energy systems will need large-scale energy storage to ensure reliability and provide power when and where it is needed. Even though lithium-ion batteries are increasingly used for large-scale storage, their costs and competition in terms of materials needed for electric vehicles are driving the need for alternative batteries for stationary energy storage systems. Molten sodium-ion batteries that operate at intermediate temperatures, approximately 150 °C or less, offer an abundant and cost-effective solution to our energy storage issues. This review paper highlights the materials, enhancements, and performance of molten Na–ion batteries that operate at temperatures at or below 150 °C for use in energy storage systems as well as an outlook on future improvements for this energy storage system.
Zhouyang Bai et al 2025 J. Electrochem. Soc. 172 021504
Subcritical and supercritical water systems, critical in nuclear energy, thermal power, and pollutant treatment, operate under extreme conditions that intensify material corrosion. In-situ electrochemical monitoring provides essential real-time data for optimizing operational conditions and enhancing corrosion prediction models. This paper evaluates high-temperature electrochemical monitoring techniques, focusing on the performance of reference electrodes and research platforms. While hydrogen electrodes offer precision, their operational complexity limits practicality. Metal/metal oxide electrodes provide robustness but suffer from potential instability, and yttria-stabilized zirconia electrodes, though suitable for high temperatures, are fragile and challenging to fabricate. External pressure-balanced reference electrodes and flow-through versions represent promising alternatives but require further refinement, particularly in thermal liquid junction potential calibration. The development of advanced research platforms, facilitating in situ electrochemical testing via techniques like electrochemical impedance spectroscopy and potentiodynamic polarization curves, is also discussed. The point defect model and its supercritical water adaptation provide a robust framework for understanding corrosion mechanisms at the microstructural level. Ongoing innovation in electrode design, platform scalability, and diagnostic techniques will be essential to advancing corrosion monitoring in extreme environments, ensuring enhanced material performance and operational safety.
M. K. Nahian and R. G. Reddy 2025 J. Electrochem. Soc. 172 022503
Lanthanides are rare Earth elements (REEs) positioned in the f-block of the periodic table and exhibit unique electronic configurations that confer exceptional magnetic, optical, and electronic properties. Consequently, they are pivotal components spanning from hard disk drives to renewable energy systems. The increasing demand for REEs in various modern technologies has driven the need for a secure and sustainable production process. Traditional methods of REEs extraction and processing, such as molten salt electrolysis, are energy-intensive and generate toxic waste, necessitating the development of alternative low-temperature separation processes. Ionic liquids (ILs), or low-temperature molten salts, have emerged as promising media for REEs electrodeposition owing to their wide potential window, excellent ionic conductivity, thermal stability, and environmental friendliness. In this review, electrochemical behavior and electrodeposition of some common REEs (Y, La, Pr, Nd, Sm, Eu, Gd, and Dy) in various ILs, along with selected cases of similar types of electrolytes called deep eutectic solvents (DESs), are discussed. The comprehensive analysis of the electrochemical behavior and deposition conditions of REEs in ILs offers valuable insights into sustainable industrial-scale REEs production in an environment-friendly way.
Guoxin Li et al 2025 J. Electrochem. Soc. 172 026501
Cathode-electrolyte interphase (CEI) is critical for inhibiting the cathode degradation to maintain cell life. However, the evolution of the CEI is still unclear due to its complex and slow dynamic process. Here we used scanning electrochemical microscopy (SECM) for in situ investigation of CEI formation process on LiFePO4 cathode. Feedback images and probe scan curves showed a heterogeneous passivation that was gently generated on the LiFePO4 particles during both charging and discharging. Besides, a LiFePO4 composited electrode was also used to investigate the CEI formation to simulate the condition of real battery system. The composited cathode does not show obvious CEI formation within first two cycles. The SECM results between the pristine LiFePO4 particles and the composited LiFePO4 indicated the dynamic accumulation of CEI, which is influenced by the ability to charge transfer kinetics of cathode materials. This approach provided a feasible consideration for the connections between the dynamic evolution of the CEI and changes in charge transfer capability of cathode during cycling.
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Highlights
In-situ investigation of cathode-electrolyte interphase formation.
The evolution of native active material and composite slurry were compared.
The electrochemical activity change upon cathode cycling are analysed in situ.
The influence of the charge transfer capability upon CEI generation is revealed.
D. Noel Buckley and Johna Leddy 2024 J. Electrochem. Soc. 171 116503
We revisit the classical derivation of the Butler-Volmer equation to include the effect of the electrode metal. If the metal is replaced by one with a different work function, keeping other conditions in the electrode constant, the chemical potential of electrons 
and the Galvani potential 
change in a complementary manner. Changes in 
and 
each impact the free energies of activation of the forward and backward electron transfer reactions, so we modify the classical expressions which relate them to applied voltage E by including also the effect of 
Inserting these expressions in an Eyring-Polyani or Arrhenius type equation in the traditional way, we obtain a modified Butler-Volmer equation which expresses current density as a function of both 
and 
The exchange current density 
appears as an exponential function of 
For the work function 
of the metal, the approximation 
yields a linear relationship between 
and 
The linear increase in 
with 
has long been reported. We show two experimental examples: the aqueous Fe2+/Fe3+ couple with positive slope and the hydrogen evolution reaction (HER) with parallel lines for the d and sp metals, both with positive slopes.
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Philip Minnmann et al 2024 J. Electrochem. Soc. 171 060514
The kinetics of composite cathodes for solid-state batteries (SSBs) relies heavily on their microstructure. Spatial distribution of the different phases, porosity, interface areas, and tortuosity factors are important descriptors that need accurate quantification for models to predict the electrochemistry and mechanics of SSBs. In this study, high-resolution focused ion beam-scanning electron microscopy tomography was used to investigate the microstructure of cathodes composed of a nickel-rich cathode active material (NCM) and a thiophosphate-based inorganic solid electrolyte (ISE). The influence of the ISE particle size on the microstructure of the cathode was visualized by 3D reconstruction and charge transport simulation. By comparison of experimentally determined and simulated conductivities of composite cathodes with different ISE particle sizes, the electrode charge transport kinetics is evaluated. Porosity is shown to have a major influence on the cell kinetics and the evaluation of the active mass of electrochemically active particles reveals a higher fraction of connected NCM particles in electrode composites utilizing smaller ISE particles. The results highlight the importance of homogeneous and optimized microstructures for high performance SSBs, securing fast ion and electron transport.
S. Yanev et al 2024 J. Electrochem. Soc. 171 020512
Li-In electrodes are widely applied as counter electrodes in fundamental research on Li-metal all-solid-state batteries. It is commonly assumed that the Li-In anode is not rate limiting, i.e. the measurement results are expected to be representative of the investigated electrode of interest. However, this assumption is rarely verified, and some counterexamples were recently demonstrated in literature. Herein, we fabricate Li-In anodes in three different ways and systematically evaluate the electrochemical properties in two- and three-electrode half-cells. The most common method of pressing Li and In metal sheets together during cell assembly resulted in poor homogeneity and low rate performance, which may result in data misinterpretation when applied for investigations on cathodic phenomena. The formation of a Li-poor region on the separator side of the anode is identified as a major kinetic bottleneck. An alternative fabrication of a Li-In powder anode resulted in no kinetic benefits. In contrast, preparing a composite from Li-In powder and sulfide electrolyte powder alleviated the kinetic limitation, resulted in superior rate performance, and minimized the impedance. The results emphasize the need to fabricate optimized Li-In anodes to ensure suitability as a counter electrode in solid-state cells.
Highlights
The fabrication of Li-In anodes needs to be optimized to ensure suitability as a counter electrode in sulfide all-solid-state batteries.
The Li-In counter electrode may often be the limiting factor of sulfide all-solid-state halfcells.
Pressing Li and In foil together results in a kinetically limited anode.
Composites from Li-In and sulfide electrolyte result in stable reference potential, superior rate performance and low impedance of the counter electrode.
Ramver Singh et al 2024 J. Electrochem. Soc. 171 013501
Electrical discharge micromachining (EDM) poses challenges to the fatigue-life performance of machined surfaces due to thermal damage, including recast layers, heat-affected zones, residual stress, micro-cracks, and pores. Existing literature proposes various ex situ post-processing techniques to mitigate these effects, albeit requiring separate facilities, leading to increased time and costs. This research involves an in situ sequential electrochemical post-processing (ECPP) technique to enhance the quality of EDMed micro-holes on titanium. The study develops an understanding of the evolution of overcutting during ECPP, conducting unique experiments that involve adjusting the initial radial interelectrode gap (utilizing in situ wire-electrical discharge grinding) and applied voltage. Additionally, an experimentally validated transient finite element method (FEM) model is developed, incorporating the passive film formation phenomenon for improved accuracy. Compared to EDM alone, the sequential EDM-ECPP approach produced micro-holes with superior surface integrity and form accuracy, completely eliminating thermal damage. Notably, surface roughness (Sa) was reduced by 80% after the ECPP. Increasing the voltage from 8 to 16 V or decreasing the gap from 60 to 20 μm rendered a larger overcut. This research's novelty lies in using a two-phase dielectric (water-air), effectively addressing dielectric and electrolyte cross-contamination issues, rendering it suitable for commercial applications.
Highlights
Better micro-hole quality through in situ sequential eco-friendly near-dry EDM & ECM
Successfully resolved dielectric-electrolyte cross-contamination in sequential processes
Unique experiments that adjust the initial radial IEG using in situ wire-EDG
Developed and validated a transient FEM model, incorporating passivation aspect
Achieved recast layer-free holes with Sa values approximately 80% lower than EDM holes
Coats et al
The large-scale commercialization of polymer electrolyte membrane fuel cells can significantly reduce greenhouse gas emissions from medium- and heavy-duty vehicle fleets. However, it is essential to enhance the long-term durability of the cathode catalyst layer (CCL), which degrades under operating conditions. Scanning transmission electron microscopy coupled with energy dispersive spectroscopy was used to investigate microstructural changes in four membrane electrode assemblies subjected to voltage cycling under different combination of stressors, including relative humidity (RH), upper and lower potential limits (UPL and LPL, respectively), dwell time, potential step, and cell temperature. The fluorine-to-platinum ratio was introduced to quantify the spatial distribution of platinum relative to the ionomer, both through-plane and in-plane. This metric, combined with nanoparticle size analysis, was used to assess initial heterogeneities and evaluate platinum losses. The main degradation modes were linked primarily to RH, dwell time, and potential step between UPL and LPL. High RH and a narrow potential step aided in the formation of a Pt depletion region near the membrane, excessive Pt band, and resulted in > 50 nm agglomerates within the CCL. Moreover, longer dwell times resulted in enhanced NP growth from electrochemical Ostwald ripening.
Rishikesan et al
In this article, we show that adventitious water/electrolyte coming from various processing steps can obscure the assessment of results for a fully vapor-fed water electrolyzer. A couple hundreds of µL per cm2 of water can sustain typical operating current densities of 10 mA/cm2geo for tens of hours, thereby not reflecting the true vapor-phase performance. This is a serious problem, especially for catalyst coated substrate architecture where surface non-uniformities behave as water pockets. We demonstrate that these water-pockets mediate the electrolysis process which can run for up to 30 hours at 10 mA/cm2geo with or without the supply of humidity. Interestingly, the vapor-fed device stops functioning at a particular charge density that corresponds to the consumption of water present in these pockets.
Liu et al
The stability of electrocatalysts in acidic solutions containing H2O2 is crucial for the large-scale application of innovative electrochemical devices utilizing H2O2 electrocatalytic reactions for energy conversion and storage. Herein, we investigate the stability of Pt/C catalysts for the H2O2 oxidation reaction (HPOR), examining the evolution of their structure and electrochemical properties. During stability testing, we found that Pt/C catalysts exhibit great activity retention despite a loss of electrochemical active area (ECA) caused by particle coarsening. The increase in Pt particle size is attributed to the H2O2-promoted formation of PtOH, followed by its electrochemical dissolution and redeposition at the HPOR potential. Remarkably, both specific activity and intrinsic kinetic activity for the HPOR increase with the Pt particle size. The enhanced intrinsic activities of larger Pt particles offset the ECA loss during long-term operation, revealing a self-compensating effect. These findings highlight Pt/C as a promising electrocatalyst for H2O2-related electrochemical devices.
Badalbayli et al
This study explores chloride molten salt electrolysis (CMSE) as a promising route for energy-efficient iron metal (Fe) production. Moderate temperature (500°C) LiCl-KCl molten salts offer excellent thermodynamic stability, high ionic conductivity and diffusivity, and high solubility for FeCl3, thereby enabling efficient Fe metal extraction at high electrowinning rates. Here, we demonstrate the two essential steps for converting taconite ore into Fe metal. First, Fe2O3 from taconite pellets was selectively leached in HCl yielding a high-purity FeCl3 aqueous solution, while the gangue components settled at the bottom. Then, anhydrous FeCl3 was electrolyzed in a LiCl-KCl eutectic molten salt at 500°C at high current density (1 A/cm2) and at high Coulombic efficiency (>85%). Analysis of the electrowon Fe deposits revealed dendritic structures with purity of >99 wt.%, which could be further improved to nearly 100 wt.% through arc re-melting. CMSE offers low specific energy consumption (3.7 kWhr/kg-Fe), competitive with H2-DRI and other electrolytic approaches being pursued globally. Our findings underscore the potential of CMSE as an energy-efficient route for electrosynthesis of Fe metal.
Iula et al
Dietary supplements play a key role in improving nutritional intake and preventing deficiencies, particularly iron supplements for pregnant women, those at risk for iron-deficiency anemia, and patients with conditions such as chronic blood loss, inflammatory bowel disease, and certain cancers. Iron is essential for several physiological functions, including oxygen transport, energy metabolism, and immune function, making its supplementation crucial for those with insufficient dietary intake or increased demand. Traditional analytical methods for quality control are effective, but they are often expensive and time-consuming. This study presents a portable electrochemical sensor for iron ion detection designed with a polyester substrate modified with gold nanoparticles. The sensor demonstrated a detection limit of 40 ppb and successfully verified its trueness on real samples of dietary supplements. These results suggest that electrochemical sensors offer a rapid and cost-effective alternative for quality control in the dietary supplement industry.
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Vanessa Scheck et al 2025 J. Electrochem. Soc. 172 039001
Vanessa Scheck et al 2025 J. Electrochem. Soc. 172 030504
Wetting of lithium-ion battery electrodes with electrolyte represents a challenge that is a mostly neglected aspect of electrode optimization. In the production of large-format cells, the rate of electrolyte wetting after filling is of particular importance, as wetting time often represents a significant bottleneck. This study employs a systematic, quantitative investigation of the wetting behavior of lithium-ion battery electrodes using a tensiometer and considering the Washburn equation. This approach facilitates a fundamental understanding of the wetting behavior of porous electrodes. To consider the influence of microstructural differences and intrinsic electrode properties, two water-based graphite anodes were employed, which exhibit the same microscopic properties but differ in their pore size distribution and binder system. The developed tensiometer method demonstrates that by employing the average pore radius obtained from pore size distribution measurements, it is feasible to consider separately microstructural and material-specific influencing factors of wetting. Further investigation revealed that one of the two electrodes exhibited superior wetting, whereby the improved wetting could be clearly attributed to the used binder system. The findings were verified by contact angle measurements of the individual binder system films, by a drop shape analyzer and by electrochemical impedance spectroscopy measurements in symmetrical pouch cells.
Alfred B. Anderson 2025 J. Electrochem. Soc. 172 036501
For many years since Gurney introduced quantum mechanics to electrochemistry, models and calculations assumed bonding and other properties at the electrochemical interface may be calculated with adequate accuracy at the potential of zero charge (PZC) and that the effect of potential lies solely in controlling the energy of the electron involved in the transfer, which comes from or goes to an external energy level. The energy of the electron is assigned to the Fermi energy, Ef, of the electrode for the particular potential being modeled. This is done in the Butler-Volmer theory as well as in several quantum mechanical modeling procedures that are introduced here. Though the PZC in fact changes as the identity, amount, and structures of molecules chemically bonded to the electrode are varied during calculations using these models, there is no control of the electrode potential in the calculations. The past two decades have seen the development of computer codes that can incorporate controlled incremental surface charging with polarizable electrolyte models that compensate it, resulting in zero net interface charge. Calculations using these codes provide accurate predictions of the potential-dependent energies of reactants and products, reversible potentials, and electron transfer activation energies.
Matthew Coats et al 2025 J. Electrochem. Soc.
The large-scale commercialization of polymer electrolyte membrane fuel cells can significantly reduce greenhouse gas emissions from medium- and heavy-duty vehicle fleets. However, it is essential to enhance the long-term durability of the cathode catalyst layer (CCL), which degrades under operating conditions. Scanning transmission electron microscopy coupled with energy dispersive spectroscopy was used to investigate microstructural changes in four membrane electrode assemblies subjected to voltage cycling under different combination of stressors, including relative humidity (RH), upper and lower potential limits (UPL and LPL, respectively), dwell time, potential step, and cell temperature. The fluorine-to-platinum ratio was introduced to quantify the spatial distribution of platinum relative to the ionomer, both through-plane and in-plane. This metric, combined with nanoparticle size analysis, was used to assess initial heterogeneities and evaluate platinum losses. The main degradation modes were linked primarily to RH, dwell time, and potential step between UPL and LPL. High RH and a narrow potential step aided in the formation of a Pt depletion region near the membrane, excessive Pt band, and resulted in > 50 nm agglomerates within the CCL. Moreover, longer dwell times resulted in enhanced NP growth from electrochemical Ostwald ripening.
Chang Liu et al 2025 J. Electrochem. Soc.
The stability of electrocatalysts in acidic solutions containing H2O2 is crucial for the large-scale application of innovative electrochemical devices utilizing H2O2 electrocatalytic reactions for energy conversion and storage. Herein, we investigate the stability of Pt/C catalysts for the H2O2 oxidation reaction (HPOR), examining the evolution of their structure and electrochemical properties. During stability testing, we found that Pt/C catalysts exhibit great activity retention despite a loss of electrochemical active area (ECA) caused by particle coarsening. The increase in Pt particle size is attributed to the H2O2-promoted formation of PtOH, followed by its electrochemical dissolution and redeposition at the HPOR potential. Remarkably, both specific activity and intrinsic kinetic activity for the HPOR increase with the Pt particle size. The enhanced intrinsic activities of larger Pt particles offset the ECA loss during long-term operation, revealing a self-compensating effect. These findings highlight Pt/C as a promising electrocatalyst for H2O2-related electrochemical devices.
Anar Badalbayli et al 2025 J. Electrochem. Soc.
This study explores chloride molten salt electrolysis (CMSE) as a promising route for energy-efficient iron metal (Fe) production. Moderate temperature (500°C) LiCl-KCl molten salts offer excellent thermodynamic stability, high ionic conductivity and diffusivity, and high solubility for FeCl3, thereby enabling efficient Fe metal extraction at high electrowinning rates. Here, we demonstrate the two essential steps for converting taconite ore into Fe metal. First, Fe2O3 from taconite pellets was selectively leached in HCl yielding a high-purity FeCl3 aqueous solution, while the gangue components settled at the bottom. Then, anhydrous FeCl3 was electrolyzed in a LiCl-KCl eutectic molten salt at 500°C at high current density (1 A/cm2) and at high Coulombic efficiency (>85%). Analysis of the electrowon Fe deposits revealed dendritic structures with purity of >99 wt.%, which could be further improved to nearly 100 wt.% through arc re-melting. CMSE offers low specific energy consumption (3.7 kWhr/kg-Fe), competitive with H2-DRI and other electrolytic approaches being pursued globally. Our findings underscore the potential of CMSE as an energy-efficient route for electrosynthesis of Fe metal.
Mariana Georges et al 2025 J. Electrochem. Soc. 172 031501
In this study, cyclic potentiodynamic polarization (CPP) tests and one-dimensional (1D) pit tests were performed to evaluate the corrosion behavior of stainless steel 316L at different temperatures and identify the critical conditions for repassivation. Downward potential scans for 1D pit samples were performed at different potential scan rates to precisely determine the repassivation potential at different pit depths. The outputs from 1D pit experiments were used to predict repassivation potentials () of three dimensional (3D) pits in bulk samples, assuming different pit geometries. Finally, these predictions were compared with the repassivation potentials obtained for bulk samples during CPP tests to verify the accuracy of predictions. This methodology provides a correlation between a controlled fundamental approach (1D pit tests) and a more practical and applied method (CPP tests on bulk samples, generating 3D pits). It also enhances the understanding of the variability in values obtained from the CPP technique, improving the reliability of this parameter.
E. C. Tredenick et al 2025 J. Electrochem. Soc. 172 030503
Lithium-ion batteries (LIB) are synonymous with the modern age of electrification, yet advances in battery design, manufacturing, and chemistry are still urgently needed. Mathematical modelling plays an important role in understanding LIB performance and can provide physics informed design directions, optimisation and explain outcomes. We present an exploration and detailed comparison of the commonly used homogenised Doyle-Fuller Newman (DFN) model and X-ray computed tomography (CT) based microstructural model for LIBs, along with experimental data. We provide insights into the relative benefits of each model and highlight why they are important to battery technology development. We compare two common cathode chemistries, lithium nickel manganese cobalt oxide (NMC), and lithium iron phosphate (LFP), and investigate discharge current density. The DFN and CT-based models show good agreement for averaged LIB metrics, such as the voltage response and active material utilization, demonstrating that homogenised, computationally inexpensive models are an essential basis for battery design and optimisation. The CT-based microstructural model provides further insight into localised particle and electrode dynamics, considering heterogeneities that are a source of battery degradation. Qualitatively, the models also compare well with experimental secondary ion mass spectrometry mapping of the Li concentration in the active particles across the electrode thickness.
Hideo Daimon et al 2025 J. Electrochem. Soc. 172 034503
Pore structure of mesoporous carbon (MPC, CNovel®) as support material for Pt catalysts in polymer electrolyte fuel cells and durability improvement of MPC by heat-treatment were investigated. Because the primary particle size of MPC is ∼2 μm, MPC is bead-milled to about 800 nm. Surface area of MPC is 1338 m2 g−1, which is comparable to that of conventional porous carbon support KB-600JD 1350 m2 g−1, while internal surface area of MPC is 1253 m2 g−1, much larger than that of KB-600JD (716 m2 g−1). Mesopore size distribution of MPC is narrower than that of KB-600JD, with central mesopore size of 4 nm. 3D-TEM analysis shows that MPC has much higher density of interconnected mesopores (2–6 nm) than KB-600JD, and cross-sectional scanning electron microscopy observations indicate that macropores (> 50 nm) coexist in MPC. These pore structures contribute to higher cell voltage of Pt/MPC over Pt/KB-600JD in the entire current density region. MPC support is heat-treated at 1800 °C–2400 °C in Ar to improve durability against high potentials (1.0–1.5 V vs RHE). Durability of Pt/MPC is higher than that of Pt/KB-600JD and monotonically improves with increasing heat-treatment temperature. MPC support maintains high surface area of 800 m2 g−1 even after heat-treatment at 2200 °C.
Gabriela G. Gerosa et al 2025 J. Electrochem. Soc. 172 030502
Extending the lifetime of lithium-ion batteries is essential to maximize resource efficiency and minimize environmental impact. Therefore, understanding the aging mechanisms that batteries undergo in their first life is critical to ensure safe operation in second-life applications. This study focuses on a comprehensive safety assessment of commercial 18650-type lithium-ion batteries with graphite||NCA chemistry. The safety of aged cells with the aging mechanism of lithium plating was tested using thermal (ARC), electrical (overcurrent, overcharge, overdischarge), and mechanical (nail penetration) abuse tests. New cells without lithium plating serve as control samples for comparison of the different safety test types and for the cells with lithium plating. The presence and absence of lithium plating is confirmed by electrochemical tests and Post-Mortem analyses (SEM, GD-OES). The cells with lithium plating exhibit significantly lower onset of self-heating temperatures, a tendency to higher maximum thermal runaway temperatures and increased EUCAR hazard levels. The results highlight potential hazards associated with lithium plating in lithium-ion batteries and the necessity to detect and avoid lithium plating in first life in order to safely reuse them in second life applications. This is part one of two papers dealing with safety testing aspects of aged cells with different degradation mechanisms.