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.
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.
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George E. Blomgren 2017 J. Electrochem. Soc. 164 A5019
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.
Jorn M. Reniers et al 2019 J. Electrochem. Soc. 166 A3189
The maximum energy that lithium-ion batteries can store decreases as they are used because of various irreversible degradation mechanisms. Many models of degradation have been proposed in the literature, sometimes with a small experimental data set for validation. However, a comprehensive comparison between different model predictions is lacking, making it difficult to select modelling approaches which can explain the degradation trends actually observed from data. Here, various degradation models from literature are implemented within a single particle model framework and their behavior is compared. It is shown that many different models can be fitted to a small experimental data set. The interactions between different models are simulated, showing how some of the models accelerate degradation in other models, altering the overall degradation trend. The effects of operating conditions on the various degradation models is simulated. This identifies which models are enhanced by which operating conditions and might therefore explain specific degradation trends observed in data. Finally, it is shown how a combination of different models is needed to capture different degradation trends observed in a large experimental data set. Vice versa, only a large data set enables to properly select the models which best explain the observed degradation.
Weilong Ai et al 2020 J. Electrochem. Soc. 167 013512
Whilst extensive research has been conducted on the effects of temperature in lithium-ion batteries, mechanical effects have not received as much attention despite their importance. In this work, the stress response in electrode particles is investigated through a pseudo-2D model with mechanically coupled diffusion physics. This model can predict the voltage, temperature and thickness change for a lithium cobalt oxide-graphite pouch cell agreeing well with experimental results. Simulations show that the stress level is overestimated by up to 50% using the standard pseudo-2D model (without stress enhanced diffusion), and stresses can accelerate the diffusion in solid phases and increase the discharge cell capacity by 5.4%. The evolution of stresses inside electrode particles and the stress inhomogeneity through the battery electrode have been illustrated. The stress level is determined by the gradients of lithium concentration, and large stresses are generated at the electrode-separator interface when high C-rates are applied, e.g. fast charging. The results can explain the experimental results of particle fragmentation close to the separator and provide novel insights to understand the local aging behaviors of battery cells and to inform improved battery control algorithms for longer lifetimes.
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.
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.
Meng Yue et al 2024 J. Electrochem. Soc. 171 050515
N-methyl-2-pyrrolidone (NMP) is the most common solvent used in coating positive electrode materials on aluminum foil during the manufacturing of lithium-ion batteries. NMP is a strongly polar aprotic solvent that effectively dissolves the polyvinylidene difluoride binder. While the majority of NMP typically evaporates during the electrode baking process, trace amounts may persist, particularly in positive electrodes containing nano-sized and highly-porous active materials. We noted residual NMP in the positive electrodes of Li-ion pouch cells containing LiMn0.8Fe0.2PO4 due to the extremely high surface area of the material and we wanted to determine the impact of this residual NMP. Therefore, a control electrolyte was purposely spiked with varying amounts of NMP and used in NMC532/graphite pouch cells to investigate the impact of residual NMP on lithium-ion battery performance. Experimental results indicate that NMP has the potential not only to neutralize the electrolyte additive ethylene sulfate but also to independently increase cathode impedance, leading to a higher rate of capacity loss during charge-discharge cycling. It is crucial to establish the appropriate procedure for baking electrodes containing NMP, both in laboratory and industrial settings, to mitigate these effects.
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.
John G. Petrovick et al 2023 J. Electrochem. Soc. 170 114519
Anion-exchange membranes (AEMs) are a possible replacement for perfluorosulfonic-acid membranes in energy-conversion devices, primarily due to the hydroxide mobile ion allowing the devices to operate in alkaline conditions with less expensive electrocatalysts. However, the transport properties of AEMs remain understudied, especially electro-osmosis. In this work, an electrochemical technique, where the open-circuit voltage is measured between two ends of a membrane maintained at different relative humidities, is used to determine the water transport number of various ionomers, including Versogen and Sustainion AEMs and Nafion cation-exchange membrane (CEM), as a function of water content and temperature. In addition, the CEMs and AEMs are examined in differing single-ion forms, specifically proton and sodium (CEM) and hydroxide and carbonate (AEM). Carbonate-form AEMs have the highest transport number (∼11), followed by sodium-form CEMs (∼8), hydroxide-form AEMs (∼6), and proton-form CEMs (∼3). Finally, a multicomponent transport model based on the Stefan-Maxwell-Onsager framework of binary interactions is used to develop a link between water transport number and water-transport properties, extracting a range for the unmeasured membrane water permeability of Versogen as a function of water content.
Sarah F. Zaccarine et al 2022 J. Electrochem. Soc. 169 064502
Polymer electrolyte membrane water electrolyzers (PEMWEs) are devices of paramount importance, enabling the large-scale storage of hydrogen from intermittent renewable energy sources such as wind and solar. But a transition towards lower noble metal catalyst loadings and intermittent operation is needed for the widespread utilization of this technology. Although kinetic losses tend to dominate in membrane electrode assembly (MEA) results, it has been suggested that morphological changes and interfaces between the catalyst, ionomer, and membrane will also contribute to overall degradation. Moreover, the combination of degradation to the catalyst layer (CL) constituents will further lead to structural changes that have not been widely explored. The multitude and complexity of degradation mechanisms, which likely occur simultaneously, require a characterization approach that can explore surfaces and interfaces at a range of length-scales to probe chemical, morphological, and structural changes of constituents within the catalyst later. This paper presents a comprehensive characterization approach that features scanning electron microscopy (SEM), scanning transmission electron microscopy with energy-dispersive X-Ray spectroscopy (STEM/EDS), X-Ray photoelectron spectroscopy (XPS), X-Ray absorption spectroscopy (XAS), and transmission X-Ray microscopy (TXM) with X-Ray absorption near-edge structure (XANES) chemical mapping to study degradation of the catalyst layer with a focus on MEAs after intermittent and steady-state operation. Catalyst changes including dissolution, oxidation, and agglomeration were observed, as well as redistribution and dissociation of the ionomer. These smaller-scale changes were found to have a large influence on overall stability of the electrodes: they caused the formation of voids and segregation of constituents within regions of the film. Delamination and collapse of the overall catalyst layer were observed in some instances. Greater changes were observed after an extended 2 V hold compared to IV cycling, but similar degradation mechanisms were detected, which suggests the larger issues would likely also be experienced during intermittent PEMWE operation. These findings would not be possible without such a systematic, multi-scale, multi-technique characterization approach, which highlights the critical importance of detailed analysis of catalyst layer degradation to propose mitigation strategies and improve long-term PEM water electrolyzer performance.
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Leila Saberi et al 2024 J. Electrochem. Soc. 171 051505
This study investigates the impact of process-induced defects such as gas pores, lack of fusions, and surface roughness on corrosion behavior of stainless steel 304L (SS304L) fabricated by laser powder bed fusion additive manufacturing. Specimens are printed with optimized process parameters but selected from different locations on the build plate. Parallel and perpendicular surfaces to the build direction are investigated and compared with corrosion properties of wrought SS304L in 5 wt% NaCl. The results reveal significant difference in corrosion behavior among specimens due to variations in their defect features. Pitting potential, pit initiation, and growth rates are found to be influenced by specimen location on the build plate. The specimen located in downstream of the shielding gas flow shows the least corrosion resistance. While no clear trends are observed between some corrosion properties and defect features, other properties show strong correlations. For example, no trend is observed for the corrosion properties in relation to pore average area fraction. However, strong correlations are observed for the corrosion properties as functions of defects maximum area. Corrosion properties linearly deteriorate as the defects maximum area increases. Roughness shows a mixed relationship with pitting potential. Comprehensive discussions on all these effects are presented.
Kokilavani R et al 2024 J. Electrochem. Soc. 171 057516
Immunosensors have emerged as vital tools in cancer diagnostics, providing simplified and rapid detection of biomarkers that are necessary for timely diagnosis. The objective of using an electrochemical immunosensor is to detect cancers at early stages, so that obtained biological information can be analyzed using artificial intelligence (AI) for deciding an appropriate treatment, avoiding false diagnosis, and preventing patient fatalities. The focus of this article is on four major reproductive cancers—breast, ovarian, cervical, and prostate cancers. Specifically, it explores the identification and optimization of biomarkers crucial for the precise detection of these cancers. Examining a decade of research, the review delves into nanotechnology-assisted electrochemical immunosensors (affinity biosensors), outlining advancements and emphasizing their potential in reproductive cancer diagnostics. Furthermore, the review contemplates avenues for enhancing sensor characteristics to pave the way for their application in field diagnosis, with a forward-looking perspective on AI-assisted diagnostics for the next generation of personalized healthcare. In navigating the landscape of reproductive cancer diagnostics, the integration of advanced technologies promises to transform our approach, offering improved accuracy and outcomes for patients.
Branimir Stamenkovic et al 2024 J. Electrochem. Soc. 171 050554
Unveiling the electrochemistry of solid-state Li2ZrCl6 halide electrolyte, we reveal its triple function as an ion conductor and a supplementary reversible, and sacrificial, electron source/sink. This groundbreaking discovery leads to a remarkable long-term enhancement of the specific capacity of industry-relevant heavily loaded LiFePO4 electrodes by several tens of percent, while significantly amplifying that of Si-based or anode-less full cells through effective compensation for side reactions. We show that these effects can potentially be tuned by adjusting the initial xLiCl-ZrCl4 composition of the solid electrolyte, which may thus become a new and mighty parameter for balancing the two electrodes.
Highlights
We used the partially reversible redox activity of halide LixZrCl4+x electrolyte.
Li2ZrCl6 acts as an ion conductor and a supplementary reversible and sacrificial e−/Li+ source.
It remarkably boosts the specific capacity of thick LiFePO4 electrodes in the 4V region
It acts as sacrificial e- source for Si-based or anode-less full cells.
Reversible and irreversible capacities can betuned by the LixZrCl4+x composition.
Jingjing Liu et al 2024 J. Electrochem. Soc. 171 054521
Water electrolysis has been used to produce green hydrogen, for which identifying optimum operation parameters is crucial to improve its energy efficiency and energy consumption. This paper used a commercial proton exchange membrane (PEM) water electrolyser stack (180 W) to demonstrate the correlation between operating current change, temperature, and water flow rate and their impact on the thermal and electrical performance of the stack. It was found that the current control regime and temperature control can offset the voltage ageing in a long-term operating electrolyser with no negative impact on the H2 production rate. For a controlled decreasing current path, in the medium range of operating current, the stack's energy efficiency was improved by 5%, and 3.7% specific energy consumption can be saved comparing to the standard operation (57.8 kWh·kg−1H2). The results provide insights into the potential optimisation in operation conditions to further increase cell energy efficiency and reduce energy consumption. This new finding sheds light on developing an energy- and cost-saving operating method for long-term green hydrogen production via water electrolysis.
Sina Hejazi et al 2024 J. Electrochem. Soc. 171 050518
Gold electrodes are used in lithium-ion battery research despite their high cost and unclear reactivity with lithium. Many equilibrium phases of gold-lithium (Au-Li) exist—solid solutions alpha, beta, and delta, and intermetallic phases AuLi3 and Au4Li15. During the first alloying reaction, the equilibrium alpha and beta phases are seemingly bypassed; a phase, presumably delta, forms at a potential of 0.25 V (all potentials vs Li/Li+), followed by the formation of AuLi3 at 0.15 V at all conditions tested and Au4Li15 at 0.05 V in select conditions. Alloying reactions are reversible to (delta), followed by the formation of another phase near 0.3 V and a low Li content phase at potentials above 0.4 V during de-alloying. Observed diffraction peaks only partially align with previous reports for all phases other than Au4Li15. The second alloying/de-alloying cycle is reversible between a low Li content phase (not pure gold) and the terminal phase. Some reaction hysteresis is present at low Li content. While the (delta)/AuLi3 reaction had a consistent potential during alloying and de-alloying, the potential otherwise varied strongly with temperature, rate, and composition, implying that gold quasi-reference electrodes may not be suitable for lithium-ion battery research.
Highlights
lithium reacts readily with gold to form at least five phases
most Au-Li phases exhibit sub-structures or solid solution ranges
electrochemical potential varies strongly with composition and conditions
substantial hysteresis in Au-Li electrochemical reactivity at low Li content
first report of electrochemical formation of Au4Li15
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Kokilavani R et al 2024 J. Electrochem. Soc. 171 057516
Immunosensors have emerged as vital tools in cancer diagnostics, providing simplified and rapid detection of biomarkers that are necessary for timely diagnosis. The objective of using an electrochemical immunosensor is to detect cancers at early stages, so that obtained biological information can be analyzed using artificial intelligence (AI) for deciding an appropriate treatment, avoiding false diagnosis, and preventing patient fatalities. The focus of this article is on four major reproductive cancers—breast, ovarian, cervical, and prostate cancers. Specifically, it explores the identification and optimization of biomarkers crucial for the precise detection of these cancers. Examining a decade of research, the review delves into nanotechnology-assisted electrochemical immunosensors (affinity biosensors), outlining advancements and emphasizing their potential in reproductive cancer diagnostics. Furthermore, the review contemplates avenues for enhancing sensor characteristics to pave the way for their application in field diagnosis, with a forward-looking perspective on AI-assisted diagnostics for the next generation of personalized healthcare. In navigating the landscape of reproductive cancer diagnostics, the integration of advanced technologies promises to transform our approach, offering improved accuracy and outcomes for patients.
Endao Zhang and Wei Song 2024 J. Electrochem. Soc. 171 052503
Hydrogen is a prime candidate for replacing fossil fuels. Electrolyzing water to produce hydrogen stands out as a particularly clean method, garnering significant attention from researchers in recent years. Among the various techniques for electrolyzing water to produce hydrogen, alkaline electrolysis holds the most promise for large-scale industrialization. The key to advancing this technology lies in the development of durable and cost-effective electrocatalysts for the hydrogen evolution reaction (HER). Self-supporting electrode is an electrode structure in which a catalyst layer is formed directly on a substrate (such as carbon cloth, nickel foam, stainless steel, etc) without using a binder and with good structural stability. In contrast to traditional nanocatalysts, self-supporting electrocatalysts offer significant advantages, including reduced resistance, enhanced stability, and prolonged usability under high currents. This paper reviews recent advancements in HER electrochemical catalysts for alkaline water electrolysis, focusing on the utilization of hydrogen-evolving catalysts such as metal sulfides, phosphides, selenides, oxides, and hydroxides. With self-supported electrocatalysts as the focal point, the paper delves into progress made in their preparation techniques, structural design, understanding of reaction mechanisms, and strategies for performance enhancement. Ultimately, the future development direction of promoting hydrogen evolution by self-supported electrocatalysts in alkaline water electrolysis is summarized.
Vinh Van Tran et al 2024 J. Electrochem. Soc. 171 056509
The quest for economical and sustainable electrocatalysts to facilitate the hydrogen evolution reaction (HER) is paramount in addressing the pressing challenges associated with carbon dioxide emissions. Molybdenum carbide-based nanomaterials have emerged as highly promising electrocatalysts for HER due to their Pt-like catalytic proficiency, exceptional stability, and the versatility of their crystal phases. Within this comprehensive review, we explore the diverse methodologies for synthesizing molybdenum carbides, including solid-gas, solid-solid, and solid-liquid phase reactions. In addition, a thorough elucidation of the hydrogen generation process through water electrolysis is provided. Furthermore, a spectrum of innovative strategies aimed at augmenting the performance of molybdenum carbides in the HER milieu is introduced, encompassing cutting-edge techniques such as phase-transition engineering, the construction of heterostructures, hetero-atom doping, the integration of hybrid structures with carbon materials, defect engineering, and meticulous surface modification. The review culminates by underscoring the current challenges and the promising prospects in the advancement of electrocatalysts for hydrogen production, with a dedicated focus on molybdenum carbide-based catalysts.
Highlights
Outstanding properties of molybdenum carbides were presented.
Various approaches for the fabrication of molybdenum carbides.
Different strategies on molybdenum carbides-based electrocatalyst for water electrolysis were discussed.
Current difficulties and possible solutions on molybdenum carbides-based electrocatalyst for water electrolysis have been introduced.
Mingyang Cao and Mingqiang Li 2024 J. Electrochem. Soc. 171 050543
Zinc ion batteries (ZIBs), as an emerging low-cost and high-safety energy storge option, have the advantages of high energy and low reduction potential. With the development of high-performance cathode materials and electrolyte systems, as well as the deepening of mechanism research, the electrochemical performance of ZIBs has been greatly improved. However, the shortcomings of various materials have hindered the development of zinc ion batteries. With the deepening of research and the deepening of understanding of various materials, a brief outlook was given on the future development of electrode materials in aqueous zinc ion batteries.
Highlights
Comparing the performance of zinc ion batteries that extensively use various electrode materials.
Propose that composite electrode can improve the shortcomings of electrode materials to a certain extent and optimize battery performance.
Propose to introduce other ions into zinc-based double-ion batteries to improve battery performance.
Minh Quang Nguyen et al 2024 J. Electrochem. Soc. 171 057507
Aquaculture, driven by increasing demands for animal proteins and fats, faces multifaceted challenges stemming from environmental factors such as climate change and pollution, alongside issues like disease susceptibility and limited therapeutic tools. However, the emergence of nanotechnology (NNT) offers a promising solution across various aquaculture domains. Nano-enhanced feed has been shown to improve fish growth rates, while nanomaterials are reducing the treatment economy by effectively eliminating contaminants. Genetic manipulation methods combined with nanobiotechnology have revolutionized fish ancestry studies, with advancements such as nanosensors and DNA-based vaccines significantly impacting fish life and immune systems. Moreover, nanotechnology plays a crucial role in enhancing fish processing, enabling sterile packaging and precise flavoring. Utilizing fishery waste through bio-nano-engineering and green nanoparticles offers new post-harvesting practices. Despite ongoing exploration, NNT presents versatile applications, prospects, and challenges in aquaculture, as detailed in this review. This paper provides an in-depth analysis of current trends, challenges, and prospects of NNT applications in aquaculture.
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S. Friedrich et al 2024 J. Electrochem. Soc. 171 050540
The impact of mechanical pressure on electrode stability in full-cells comprising microscale silicon-dominant anodes and NCA cathodes was investigated. We applied different mechanical pressures using spring-compressed T-cells with metallic lithium reference electrodes enabling us to analyze the electrode-specific characteristics. Our investigation covers a wide pressure range from 0.02 MPa (low pressure - LP) to 2.00 MPa (ultra high pressure - UHP) to determine the optimal pressure for cyclic lifetime and energy density. We introduce an experimental methodology considering single-component compression to adjust the cell setup precisely. We characterize the cells using impedance spectroscopy and age them at C/2. In the post-mortem analysis, cross-sections of the aged anodes are measured with scanning electron microscopy. The images are analyzed with regard to electrochemical milling, thickness gain, and porosity decrease by comparing them to the pristine state. The results indicate that cycling at UHP has a detrimental effect on cycle life, being almost two-fold shorter when compared to cycling at normal pressure (NP, 0.20 MPa). Scanning electron microscopy showed a dependency of the thickness and the porosity of the aged silicon anodes on the applied pressure, with coating thickness increasing and porosity decreasing for all pressure settings, and a correlation between thickness and porosity.
Hong Zhang et al 2024 J. Electrochem. Soc. 171 047510
Ordered Pt/SnO2 composite porous thin films were prepared for fabrication of planar mixed-potential hydrogen sensors. Characterization of the Pt/SnO2 films revealed that Pt elements were primarily loaded in Pt° form on the SnO2 film surface and did not significantly change the morphology of the film electrodes. The potentiometric response of Pt/SnO2 thin films to hydrogen varied with the Pt loading contents. Compared to the pristine SnO2 film, the 1 at% and 2 at% Pt-loaded SnO2 composite films exhibited 1.6 and 2.0 times higher potentiometric response to 300 ppm hydrogen at 500 °C, with a similar response time of 6–10.5 s. By assembling an array of sensors composed of SnO2 films loaded with 1 at% and 2 at% Pt, and using principal component analysis, discrimination of hydrogen and four interfering gases (ammonia, carbon monoxide, nitrogen dioxide, and propane) in the concentration range of 100–300 ppm was achieved. The sensing behaviors of the Pt/SnO2 composite thin films were discussed in relation to the competitive promotion effects for the heterogeneous and electrochemical catalytic activities by Pt loading.
Highlights
Potentiometric hydrogen sensors based on Pt/SnO2 thin films were fabricated.
Hydrogen sensing response was enhanced by loading 1 at% and 2 at% Pt.
The sensing behavior was discussed by the Pt competitive promotion effects.
Discrimination of hydrogen and four interfering gases was achieved.
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
Yuefan Ji and Daniel T. Schwartz 2023 J. Electrochem. Soc. 170 123511
Analytical theory for second harmonic nonlinear electrochemical impedance spectroscopy (2nd-NLEIS) of planar and porous electrodes is developed for interfaces governed by Butler-Volmer kinetics, a Helmholtz (mainly) or Gouy-Chapman (introduced) double layer, and transport by ion migration and diffusion. A continuum of analytical EIS and 2nd-NLEIS models is presented, from nonlinear Randles circuits with or without diffusion impedances to nonlinear macrohomogeneous porous electrode theory that is shown to be analogous to a nonlinear transmission-line model. EIS and 2nd-NLEIS for planar electrodes share classic charge transfer RC and diffusion time-scales, whereas porous electrode EIS and 2nd-NLEIS share three characteristic time constants. In both cases, the magnitude of 2nd-NLEIS is proportional to nonlinear charge transfer asymmetry and thermodynamic curvature parameters. The phase behavior of 2nd-NLEIS is more complex and model-sensitive than in EIS, with half-cell NLEIS spectra potentially traversing all four quadrants of a Nyquist plot. We explore the power of simultaneously analyzing the linear EIS and 2nd-NLEIS spectra for two-electrode configurations, where the full-cell linear EIS signal arises from the sum of the half-cell spectra, while the 2nd-NLEIS signal arises from their difference.
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Yang et al
Lithium metal battery (LMB) technology is very attractive as it has the potential to offer energy densities greater than 1000 Wh/L. A thorough investigation of cell performance against various vehicle operational requirements is required for the successful deployment of this technology in practical electric vehicle applications. For instance, there have been several reports on the high reactivity of Li metal with electrolyte leading to continuous electrolyte consumption in LMB. Due to these parasitic reactions, electrolyte dries out and Li metal morphological changes occur leading to reduced cycle life of lithium metal batteries. In contrast, there are also claims of stable and long cycle life of LMB in several publications, although most of the results were obtained in coin cells. In this report we will take a closer look at the LMB cell to understand its performance and manufacturability. Our goal is to investigate and provide a thorough report on advances and challenges starting from the cell level down to component design of LMB.
Stradley et al
Mg batteries are a promising alternative to Li-based chemistries due to the high abundance, low cost, and high volumetric capacity of Mg relative to Li. Mg is also less prone to dendritic plating morphologies, promising safer operation. Mg plating and stripping is highly efficient in chloride-containing electrolytes; however, chloride is incompatible with many candidate cathode materials. In this work, we capitalize on the positive effect of chloride by using transition metal chloride cathodes with a focus on low cost, Earth-abundant metals. Both soluble and sparingly soluble chlorides show capacity fade upon cycling. Active material dissolution and subsequent crossover to the Mg anode are the primary drivers of capacity fade in highly soluble metal chloride cathodes. We hypothesize that incomplete conversion and chemical reduction by the Grignard-based electrolyte are major promoters of capacity fade in sparingly soluble metal chlorides. Modifications to the electrolyte can improve capacity retention, suggesting that future work in this system may yield low cost, high retention Mg-MClx batteries.
Rüther et al
Interpreting impedance spectra of electrochemical systems using the distribution of relaxation times analysis remains an incompletely solved task. This study carefully examines various challenges related to the interpretation of resulting distributions of relaxation times using a closed-form lumped Doyle-Fuller-Newman model. First, the physical and phenomenological interpretation of peaks in the distribution of relaxation times are analyzed through a global sensitivity analysis. Second, the assignment of processes to specific ranges of time constants is investigated. Third, the use of half cells for the characterization of full cells is examined, and the clear limitations associated with the use of lithium metal counter electrodes are pointed out. Furthermore, the study provides first insights into the effects of distributed processes such as charge transfer, double-layer effects, and solid-state diffusion. Several prevailing interpretations in the literature are challenged and new insights and guidelines for interpreting distributions of relaxation times are offered.
Wang et al
Liquid alkaline water electrolyzers (LAWEs), being the most commercially mature electrolysis technology, play a pivotal role in large-scale hydrogen production. However, LAWEs suffer from low operational efficiency, primarily due to un-optimized electrode structure and chemical compositions. Thus, we investigated how various electrode configurations could impact LAWE performance. Our results show that Ni felt electrodes outperform the conventional Ni foam thanks to improved electrochemical active surface area (ECSA) and preferred electrode surface structure that minimizes the micro-gaps in between the electrode and separator. By comparing the stainless steel (SS) felt electrodes with Ni felt electrodes, SS not only shows better oxygen evolution reaction activity but also improved hydrogen evolution reaction activity, which is less studied in the literature. We also show that a bilayer structure with small pore radius facing the separator could further improve LAWE performance by further optimizing interfacial contact between electrode and separator. These findings enable LAWEs to sustain 2 A cm-2 at 2.2 V and operate steadily at 1 A cm-2 for nearly 600 h with negligible performance decay. Our studies establish criteria for selecting electrodes to achieve high-performance LAWE and, in turn, expedite the adoption of LAWEs in hydrogen production and the transition towards low-carbon economies.
Song et al
During the molten salt electrolysis of magnesium production, water in the magnesium chloride (MgCl2) feedstock poses significant interference, reducing the current efficiency. Employing rare earth chlorides (RECl3) to assist in dehydrating magnesium chloride and producing Mg-RE master alloys emerges as an effective strategy. This study investigated the transformation process in the hydrolysis reaction of low-hydrate MgCl2 within the molten salt, examining the electrochemical activity of its hydrolysis products using Cyclic voltammetry (CV). Additionally, a thermodynamic analysis of the reaction between hydrolyzate MgO and RECl3 was performed at electrolysis temperatures. By integrating CV and Square wave voltammetry (SWV) with X-ray diffraction (XRD) analysis, the study explored the alterations in the electrochemically active components of the molten salt system following the addition of RECl3 to the KCl-NaCl molten salt containing MgO.
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Leila Saberi et al 2024 J. Electrochem. Soc. 171 051505
This study investigates the impact of process-induced defects such as gas pores, lack of fusions, and surface roughness on corrosion behavior of stainless steel 304L (SS304L) fabricated by laser powder bed fusion additive manufacturing. Specimens are printed with optimized process parameters but selected from different locations on the build plate. Parallel and perpendicular surfaces to the build direction are investigated and compared with corrosion properties of wrought SS304L in 5 wt% NaCl. The results reveal significant difference in corrosion behavior among specimens due to variations in their defect features. Pitting potential, pit initiation, and growth rates are found to be influenced by specimen location on the build plate. The specimen located in downstream of the shielding gas flow shows the least corrosion resistance. While no clear trends are observed between some corrosion properties and defect features, other properties show strong correlations. For example, no trend is observed for the corrosion properties in relation to pore average area fraction. However, strong correlations are observed for the corrosion properties as functions of defects maximum area. Corrosion properties linearly deteriorate as the defects maximum area increases. Roughness shows a mixed relationship with pitting potential. Comprehensive discussions on all these effects are presented.
Branimir Stamenkovic et al 2024 J. Electrochem. Soc. 171 050554
Unveiling the electrochemistry of solid-state Li2ZrCl6 halide electrolyte, we reveal its triple function as an ion conductor and a supplementary reversible, and sacrificial, electron source/sink. This groundbreaking discovery leads to a remarkable long-term enhancement of the specific capacity of industry-relevant heavily loaded LiFePO4 electrodes by several tens of percent, while significantly amplifying that of Si-based or anode-less full cells through effective compensation for side reactions. We show that these effects can potentially be tuned by adjusting the initial xLiCl-ZrCl4 composition of the solid electrolyte, which may thus become a new and mighty parameter for balancing the two electrodes.
Highlights
We used the partially reversible redox activity of halide LixZrCl4+x electrolyte.
Li2ZrCl6 acts as an ion conductor and a supplementary reversible and sacrificial e−/Li+ source.
It remarkably boosts the specific capacity of thick LiFePO4 electrodes in the 4V region
It acts as sacrificial e- source for Si-based or anode-less full cells.
Reversible and irreversible capacities can betuned by the LixZrCl4+x composition.
Jingjing Liu et al 2024 J. Electrochem. Soc. 171 054521
Water electrolysis has been used to produce green hydrogen, for which identifying optimum operation parameters is crucial to improve its energy efficiency and energy consumption. This paper used a commercial proton exchange membrane (PEM) water electrolyser stack (180 W) to demonstrate the correlation between operating current change, temperature, and water flow rate and their impact on the thermal and electrical performance of the stack. It was found that the current control regime and temperature control can offset the voltage ageing in a long-term operating electrolyser with no negative impact on the H2 production rate. For a controlled decreasing current path, in the medium range of operating current, the stack’s energy efficiency was improved by 5%, and 3.7% specific energy consumption can be saved comparing to the standard operation (57.8 kWh·kg−1H2). The results provide insights into the potential optimisation in operation conditions to further increase cell energy efficiency and reduce energy consumption. This new finding sheds light on developing an energy- and cost-saving operating method for long-term green hydrogen production via water electrolysis.
Sina Hejazi et al 2024 J. Electrochem. Soc. 171 050518
Gold electrodes are used in lithium-ion battery research despite their high cost and unclear reactivity with lithium. Many equilibrium phases of gold-lithium (Au-Li) exist—solid solutions alpha, beta, and delta, and intermetallic phases AuLi3 and Au4Li15. During the first alloying reaction, the equilibrium alpha and beta phases are seemingly bypassed; a phase, presumably delta, forms at a potential of 0.25 V (all potentials vs Li/Li+), followed by the formation of AuLi3 at 0.15 V at all conditions tested and Au4Li15 at 0.05 V in select conditions. Alloying reactions are reversible to (delta), followed by the formation of another phase near 0.3 V and a low Li content phase at potentials above 0.4 V during de-alloying. Observed diffraction peaks only partially align with previous reports for all phases other than Au4Li15. The second alloying/de-alloying cycle is reversible between a low Li content phase (not pure gold) and the terminal phase. Some reaction hysteresis is present at low Li content. While the (delta)/AuLi3 reaction had a consistent potential during alloying and de-alloying, the potential otherwise varied strongly with temperature, rate, and composition, implying that gold quasi-reference electrodes may not be suitable for lithium-ion battery research.
Highlights
lithium reacts readily with gold to form at least five phases
most Au-Li phases exhibit sub-structures or solid solution ranges
electrochemical potential varies strongly with composition and conditions
substantial hysteresis in Au-Li electrochemical reactivity at low Li content
first report of electrochemical formation of Au4Li15
Julian Stiegeler et al 2024 J. Electrochem. Soc. 171 054517
Polymer electrolyte fuel cells for heavy-duty applications require lifetimes beyond 30,000 h, which poses a durability challenge. In this study, we investigated the influence of various factors on loss of electrochemically active surface area (ECSA) in the cathode, which is a major limiting factor. We derive a parameter range from simulated drive cycles showing that the voltage ranges between 0.70 and 0.85 V and that the cells are in idle state at upper potential limit (UPL) most of the time. We evaluate the influence and interaction of UPL, lower potential limit (LPL), temperature, relative humidity, and cycle time on ECSA and performance at four different operating conditions after 10,000 potential cycles based on 25 experiments. The results indicate that UPL and the hold time at UPL have the strongest impact on degradation, while LPL has a small impact, which does not increase below the potential of full platinum reduction (0.55 V) or hold times longer than 2 s. Furthermore, the interaction of humidity with other factors becomes significant for long experiment times. In summary, the findings of this work can serve as guidelines for minimizing ECSA loss, e.g. by keeping the fuel cell in a benign operation regime via systems control.
Endao Zhang and Wei Song 2024 J. Electrochem. Soc. 171 052503
Hydrogen is a prime candidate for replacing fossil fuels. Electrolyzing water to produce hydrogen stands out as a particularly clean method, garnering significant attention from researchers in recent years. Among the various techniques for electrolyzing water to produce hydrogen, alkaline electrolysis holds the most promise for large-scale industrialization. The key to advancing this technology lies in the development of durable and cost-effective electrocatalysts for the hydrogen evolution reaction (HER). Self-supporting electrode is an electrode structure in which a catalyst layer is formed directly on a substrate (such as carbon cloth, nickel foam, stainless steel, etc) without using a binder and with good structural stability. In contrast to traditional nanocatalysts, self-supporting electrocatalysts offer significant advantages, including reduced resistance, enhanced stability, and prolonged usability under high currents. This paper reviews recent advancements in HER electrochemical catalysts for alkaline water electrolysis, focusing on the utilization of hydrogen-evolving catalysts such as metal sulfides, phosphides, selenides, oxides, and hydroxides. With self-supported electrocatalysts as the focal point, the paper delves into progress made in their preparation techniques, structural design, understanding of reaction mechanisms, and strategies for performance enhancement. Ultimately, the future development direction of promoting hydrogen evolution by self-supported electrocatalysts in alkaline water electrolysis is summarized.
Li Yang et al 2024 J. Electrochem. Soc.
Lithium metal battery (LMB) technology is very attractive as it has the potential to offer energy densities greater than 1000 Wh/L. A thorough investigation of cell performance against various vehicle operational requirements is required for the successful deployment of this technology in practical electric vehicle applications. For instance, there have been several reports on the high reactivity of Li metal with electrolyte leading to continuous electrolyte consumption in LMB. Due to these parasitic reactions, electrolyte dries out and Li metal morphological changes occur leading to reduced cycle life of lithium metal batteries. In contrast, there are also claims of stable and long cycle life of LMB in several publications, although most of the results were obtained in coin cells. In this report we will take a closer look at the LMB cell to understand its performance and manufacturability. Our goal is to investigate and provide a thorough report on advances and challenges starting from the cell level down to component design of LMB.
Thomas Roth et al 2024 J. Electrochem. Soc. 171 050547
The anode overhang is usually cited to prevent lithium plating at the cell edges of lithium-ion batteries. Still, numerous reports in the literature show lithium plating at the cell edge, which is typically referred to as edge plating. Edge plating is often attributed to inhomogeneous lithium distribution, thermal gradients, or pressure-dependent effects. This work presents an easy-to-implement two-dimensional electrochemical model demonstrating inhomogeneous lithiation induced by the anode overhang, which can explain experimentally observed edge plating. First, the mechanism of inhomogeneous lithiation due to the anode overhang is explained in detail. Then, a parameter study on charge protocol and geometric cell properties is presented, and the implications for cell applications are analyzed. Finally, the findings are discussed and put into a broader perspective of cell design, manufacturing, and fast charging application. In Part II of this work, the simulation is validated experimentally using multi-reference electrode single-layer pouch cells.
J. Marvin Torrie et al 2024 J. Electrochem. Soc. 171 053508
A simply constructed, stable, Ni/Ni2+ saturated reference electrode (SRE) has potential to measure thermodynamic behavior of molten chloride salts more reliably. Like the Ag/Ag+ reference electrode (RE), the Ni/Ni2+ SRE is made of commercially available materials. Initial experiments in molten CaCl2 and LiCl show the Ag/Ag+ RE potential drifting two times faster than the SRE. Furthermore, experiments show the replicability of SREs by comparing two Ni/Ni2+ SREs with different compositions of NiCl2 which is supportive of saturated phase behavior.
Steven H. Stradley et al 2024 J. Electrochem. Soc.
Mg batteries are a promising alternative to Li-based chemistries due to the high abundance, low cost, and high volumetric capacity of Mg relative to Li. Mg is also less prone to dendritic plating morphologies, promising safer operation. Mg plating and stripping is highly efficient in chloride-containing electrolytes; however, chloride is incompatible with many candidate cathode materials. In this work, we capitalize on the positive effect of chloride by using transition metal chloride cathodes with a focus on low cost, Earth-abundant metals. Both soluble and sparingly soluble chlorides show capacity fade upon cycling. Active material dissolution and subsequent crossover to the Mg anode are the primary drivers of capacity fade in highly soluble metal chloride cathodes. We hypothesize that incomplete conversion and chemical reduction by the Grignard-based electrolyte are major promoters of capacity fade in sparingly soluble metal chlorides. Modifications to the electrolyte can improve capacity retention, suggesting that future work in this system may yield low cost, high retention Mg-MClx batteries.