In a recent study, Solchenbach et al. [1] demonstrated that the volume change of the battery electrode active material causes electrolyte motion into and out of the jelly roll upon cycling. This results in a salt concentration gradient along the longitudinal direction of the cylindrical cell, also named EMSI (electrolyte motion induced salt inhomogeneity). This effect, has been reported to cause loss of cell capacity, increase in resistance, and eventually localized lithium plating after only 130 cycles following a fast-charging based protocol. Building up on this knowledge, this study aims at testing the effect of long rest periods, differently distributed within a standard cycling protocol. This aspect is tightly correlated to the EMSI effect, as days are required to smoothen concentration gradients in the longitudinal plane (cm scale). Therefore, the intention was to investigate the presence of a build-up effect caused by the continuous cycling protocols of accelerated ageing tests and the influence of short and frequent or long and infrequent rest periods. Three pairs of cylindrical cells (4690, 31Ah) have been cycled under the same current and voltage conditions (C/2 charge - C/3 discharge, between 4.2 and 3V), with a total rest period of 150 hours every 100 cycles. This rest period is allowed either between every cycle (90 minutes each – high freq. rest), every 10 cycles (15 hours – mid freq. rest) or every 100 cycles (150 hours – low freq. rest). To study the long-term impact of both the rest periods and the electrolyte motion phenomenon, cells were cycled until the end-of-life condition of 80% residual capacity. After cycling, one cell from each test case was first CT-scanned and subsequently disassembled for post-mortem characterization. This allowed to obtain information about the electrode materials (electrochemistry, 7 Li NMR, SEM, XRD) and the electrolyte salt distribution within each cell ( 19 F NMR). The capacity fade of the test cases displayed similar trends with slightly faster degradation of the high frequency rest protocol. The post-mortem analysis highlighted different levels of heterogeneous degradation for all the test cases, with material degradation dominated by the SiO x -Gr negative electrode and a clear trend of inhomogeneous salt distribution. [1] Solchenbach, Sophie, et al. "Electrolyte motion induced salt inhomogeneity–a novel aging mechanism in large-format lithium-ion cells." Energy & Environmental Science 17.19 (2024): 7294-7317.

The integration of proton exchange membrane fuel cells (PEMFCs) in heavy-duty vehicles and other demanding applications, such as aviation, would be simplified if the stacks could operate above 100 degrees C instead of the traditional low temperature (LT, up to 80 degrees C), thereby allowing a reduction in cooling system in size and power. This review offers a comprehensive compilation of experimental studies reported in the literature on PEMFCs operated in the intermediate temperature (IT)-range, here defined as above 80 degrees C and up to 120 degrees C, which represented the targeted upper temperature for PEMFCs. Membranes, electrodes and gas diffusion layers for ITPEMFCs are discussed. Particular attention is paid to polymers in membranes and catalyst layer ionomers. Results from current state-of-the-art perfluorosulfonic acids and alternatives, including hydrocarbon polymers, are evaluated considering their properties and limitations. Further, system benefits and drawbacks of IT- compared to the traditional LT-operation are discussed, such as the interplay between vapour and oxygen pressure, hydrogen crossover and water management. We report on the lack of consistency between ex-situ and in-situ studies and underline the importance of in-situ tests, proposing guidelines to evaluate novel materials. For IToperation, the development of stable polymers, which are the weakest components of the PEMFCs, is the most urgent challenge. As degradation happens faster at higher temperatures, further long-term tests are needed above 80 degrees C and accelerated stress tests should be specifically designed for IT-operation according to the polymer chemistries. We conclude that, compared to LT-, IT-operation requires improved materials and additional research.

The electrode's composition and structure, affecting ion-conduction and water uptake and transport, is crucial for polymer electrolyte fuel cells. This study investigates the role of particles versus dispersed ionomer based on poly (arylene piperidinium) (PAP) for AEMFC. Mixed ionomer electrodes, consisting of linear PAP ionomers and crosslinked particles, are synthesized and evaluated in AEMFC single cells through electrochemical characterizations. The addition of insoluble particles corresponding to 5 % of total electrode weight leads to an increase in peak power density of similar to 60 % in comparison to when employing electrodes based purely on the linear ionomers such as poly(terphenyl piperidinium) and poly(terphenyl piperidinium-co-trifluoroacetophenone), respectively. A deconvolution of cell resistance contributions based on electrochemical impedance spectroscopy (EIS) data, combined with a distribution of relaxation times analysis (DRT), shows a significant decrease in effective cathode charge transfer resistance. This is attributed to particles serving as bridges between the membrane and the reaction sites, leading to increased ionic conductivity and active site utilization via shortening the distance of water and ion transport through the ionomer phase. In an expansion of the study, PAP particles were added to an electrode sample based on commercial Aemion + (TM). A smaller peak power density increase of 27 % was observed, emphasizing the importance of matching the chemical structures of the particles, membrane, and linear ionomer.

Biomass gasification-derived gases require conditioning to meet the requirements of downstream energy conversion processes. Although the compatibility of reversible molten carbonate fuel cells (RMCFCs) with cleaned product gases has been previously demonstrated, their potential to condition gas compositions toward application-specific requirements remains insufficiently understood. This work studies the use of an RMCFC fed with cleaned product gas as an electrochemical gas-conditioning unit, quantifying the influence of operating conditions on outlet gas composition. A steady-state numerical model incorporating experimentally obtained polarisation curves was used to evaluate the effects of current density, inlet temperature (600–650 °C), and inlet gas humidity (20–40%) on outlet gas compositions at both electrodes and on the cell temperature. Gas-phase equilibrium reactions, namely internal steam reforming and the water–gas shift reaction, were coupled with electrochemical reactions to capture interactions between electrochemical conversion and thermochemical gas-phase equilibria. The outlet compositions were evaluated for their suitability for downstream applications, namely power generation in fuel cell mode, hydrogen-rich gas production, and syngas conditioning toward H2/CO ≈ 2 for methanol and Fischer–Tropsch synthesis in electrolysis mode. The results show that current density acts as a key control parameter governing the coupled electrochemical–thermochemical behaviour. Depending on operating conditions and current density, the same gas feed can support power generation or be upgraded to hydrogen-rich gas or synthesis-relevant syngas. In particular, indirect steam gasification (ISG)-derived cleaned product gas, under specific operating conditions, supports simultaneous power generation and syngas conditioning for methanol and Fischer–Tropsch synthesis.

In nature, almost all materials perform multiple functions simultaneously, whereas man-made materials are typically optimized for a single function. Multifunctional materials offer a pathway to mimic nature, enabling materials that require fewer resources, reduce system mass and volume, and improve energy efficiency. Although multifunctional materials exist, they rarely combine more than two functions at the same time. Here we demonstrate a carbon fiber (CF) composite material that exhibits five different physical functions simultaneously: structural load carrying, energy storage, strain sensing, shape-morphing, and energy harvesting. This is achieved by utilizing the mechanical properties of CFs, their ability to reversibly intercalate Li-ions in their atomic structure, and the piezo-electrochemical transducer effect observed in lithiated CFs. The composite provides flexible performance, as it can be tailored toward specific functions through the design of its constituent materials and architecture. This concept could lead to significantly more efficient structural materials for a wide range of future applications.

There is currently a drive to operate proton exchange membrane fuel cells at temperatures above 80 degrees C. To achieve this, all aspects of the fuel cell need to be investigated to ensure that performance and durability are maintained. In this work we systematically investigated carbon corrosion from 70 degrees C to 120 degrees C and 40 and 70 % relative humidity (RH). The investigation was done by cyclic voltammetry up to 1.4 V vs RHE with simultaneous mass spectrometry measurements to quantify the produced carbon dioxide. The obtained results were modelled to differentiate the effects of temperature, water partial pressure and different types of carbon corrosion. The results show that the carbon corrosion is mainly affected by the water partial pressure, which increases exponentially with temperature if RH is kept constant. This explains why an increase of temperature (at constant humidity) and an increase of humidity (at constant temperature) lead to faster corrosion kinetics. With current materials, to contrast the effect of the water partial pressure, the upper cell voltage limit in operation must be lowered. The combination of temperatures above 100 degrees C with high relative humidity at high voltage requires material improvement or additional mitigation strategies to avoid excessive carbon corrosion.

The mechanical properties of gas diffusion layers (GDLs) in proton exchange membrane fuel cells (PEMFCs critically govern compression-dependent transport phenomena that control local performance and durability. This work presents a systematic, self-consistent characterization of orthotropic mechanical behavior, through-plane (TP) thermal and electrical conductivities, in-plane (IP) gas permeability, and structural properties for five commercial GDLs-wet-laid carbon papers (Toray TGP-H-060 with 5 and 30 wt% PTFE; SGL 29BA uncoated; SGL 28BC MPL-coated) and one hydroentangled non-woven (Freudenberg H23C7)-measured under controlled compressive loads (0.5-3 MPa). Additional GDL materials are benchmarked against literature data. Increased PTFE content significantly stiffens the fibrous network, while microporous layer (MPL) addition introduces additional through-plane bulk transport resistance. In-plane gas permeability decreases by approximately 70-90% over the investigated compression range for all materials, with the most pronounced reductions (up to two orders of magnitude) observed in SGL 28BC due to pronounced MPL intrusion into the substrate, forming a mixed fiber-MPL zone that reduces lateral macropore connectivity and increases flow resistance. Physically motivated models are applied to interpret the observed trends. Effective percolation theory correlations describe the nonlinear evolution of thermal and electrical conductivities with solid volume fraction, yielding interpretable parameters that explain material class differences and thermal-electrical decoupling. In addition, a hyperelastic two-power-law strain energy framework that mechanistically captures the full compressive response-from initial fiber bending, through topology-controlled stiffening, to high-strain densification-while maintaining thermodynamic consistency and finite-element compatibility is proposed. While Toray TGP-H-060 is extensively benchmarked in the literature, coupled compression-dependent multi-property datasets remain scarce for hydroentangled non-woven GDLs and MPL-coated roll-good grades. The comprehensive dataset and modeling framework presented here provide a robust foundation for high-fidelity three-dimensional PEMFC stack simulations, enabling improved material selection, stack design, and performance and durability optimization.

Even though the staging mechanism of graphite has been studied extensively by, primarily, diffraction methods, the nature of dilute stages with stoichiometries lower than LiC 12 remains an open question. Here we reconsider the stages from the perspective of Li ion dynamics as observed by 7 Li NMR spin relaxation. We find that in stage-1 (LiC 6 ) and 2 (LiC 12 ), the Li ions are quite immobile which is consistent with dense Li-filled interlayers. In stage-2L (LiC 18 ), Li ion motion is fast with low activation energy indicating the presence of easily accessible vacancies. The data supported by confocal Raman spectroscopy also suggest that the coexisting stage-2 and stage-2L 2 domains are in the order to micrometers, close to the grains size. We propose that the split Raman G-band observed in stage-2L is connected to in-plane inhomogeneity of electron distribution induced by locally occupied and vacant Li + sites. The phase equilibrium of stage-2 and stage-2L domains is temperature-dependent, with low temperature favoring the low-entropy stage-2 phase.

An increasing demand for alternative electrolyte systems is emerging to address limitations associated with traditional liquid electrolytes in lithium-ion batteries (LIBs). Hybrid polymer-liquid electrolytes (HEs) combine the merits of solid polymers and liquid electrolytes in a heterogeneous phase-separated system where the polymer phase encapsulates the liquid ion-conducting phase. These electrolytes are synthesized through polymerization-induced phase separation (PIPS), resulting in the formation of a porous three-dimensional polymer network. Carbon black (CB) serves as conductive additive in LIBs electrodes, enhancing electric conductivity and thereby improving the battery performance and lifespan. How CB, already present in conventional electrodes, affects the PIPS process during the formation of HEs for LIBs, focusing on the material interactions and the formed microstructure properties, has been investigated. Addition of CB does not negatively affect the result of PIPS process, and it permits high conversion rate and compatibility with HE at all CB concentrations investigated. Morphological analysis in combination with nuclear magnetic resonance (NMR) and electrochemical impedance spectroscopy (EIS) reveals consistent macroporous and mesoporous structures, indicating the robustness of HEs to CB content variation. Understanding the interaction between CB and HEs during the manufacturing process and the impact of CB on the structural integrity and compatibility of the HE system, aids the integration of HEs with existing electrode materials in practical battery configurations.

To prolong the lifetime of lithium-ion batteries and implement repurposed cells in milder applications, several challenges need to be overcome. Besides better understanding of the degradation and sources of performance loss, reliable methods to characterize the battery state of health (SOH) based on the in situ measurable signals voltage, current and surface temperature are needed. In addition, path-dependent degradation should be explored to match batteries with the most suitable application. In this study we analyse the performance and degradation of Tesla (LiNixCoyAlzO2 (NCA)/Gr-SiOx) lithium-ion batteries in 2nd applications. Previously cycleaged cells were selected with 64-58 % remaining capacity and similar impedance patterns to be cycled at 40 degrees C with a Frequency Regulation (FR) cycle or at 1C-constant current (CC) between 20 and 80 % State-of-Charge. The results demonstrate that FR cycling is suitable as 2nd application causing only minor additional degradation. For 1C CC-cycling, over 1100 equivalent full cycles was obtained down to 49 % remaining capacity, although with large cell polarization. The considerable mass transport limitations and concentration gradients under load could not be captured by impedance measurements but was better identified with Capacity Difference Analysis (CDA) proposed to be utilized as an additional SOH evaluation method for aged battery cells.

The last decade has seen an enormous improvement of energy density for lithium-ion battery cells, particularly for automotive grade cells intended for use in electrified vehicles. This has led to vastly improved range for battery electric vehicles as well as for plug-in hybrids. However, the challenge of uncertain battery lifetime remains. The ageing effect due to fast charging is especially difficult to predict due to its non-linear dependence on charge rate, state-of-charge and temperature. We here present results from fast charging (1C and 3C in a 20 % to 80 % SOC-level) of several energy-optimized, prismatic lithium-ion battery cell generations utilizing NMC/graphite chemistry through comparison of capacity retention, resistance and dQ/dV analysis. Considerable improvements are observed throughout cell generations and the results imply that acceptable cycle life can be expected, even under fast charging, when restricting the usage of the available battery capacity. Even though this approach reduces the useable energy density of a battery system, this trade-off could still be acceptable for vehicle applications where conventional overnight charging is not possible. The tested cell format (the VDA PHEV2-standard) has been used for a decade in different electrified vehicles. The ongoing development and improvement of this cell format by several battery cell manufacturers suggests it will continue to be a good choice for future vehicles.

Water is a key factor in anion-exchange membrane fuel cells, since it is both a product and a reactant, and humidifies the membrane and the ionomer phase. To optimize the operation conditions preventing cathode drying and anode flooding, better knowledge on the water transport is needed. In this work, the water transport across an AemionTM membrane is quantified for different applied water partial pressure differences and current densities. Two membrane thicknesses, 25 and 50 mu m, are studied, as well as two gas diffusion layers (GDLs) of different hydrophobicity: the hydrophobic Sigracet 25BC treated with polytetrafluoroethylene (PTFE), and Freudenberg H23C2 being hydrophilic as it is not treated with PTFE. The measurements show that having a hydrophilic GDL on both electrodes results in poor electrochemical performance, and restricted water transport. Although the highest water molar flux was observed for hydrophilic GDL on cathode and hydrophobic GDL on anode, the best electrochemical performance was observed for the opposite combination. A water transport model considering absorption/desorption resistance, electroosmotic drag and diffusion was deployed. The best fit of the model to the experimental data was obtained with a water drag coefficient of 2, and almost about 30% difference in absorption/desorption coefficient due to different GDLs.

The kinetics of oxygen reduction reaction (ORR) on Ag and Pt thin-layer electrodes was studied in an anion exchange membrane fuel cell (AEMFC). The two-dimensional nature of these layers minimizes the effects of current distribution and mass transport. The ORR activities were evaluated at 80°C and 100 % RH via polarization curves. Compared to Pt, Ag displays a lower open circuit potential and a lower performance at high voltages. For Ag an anodic peak at 0.82 V was obtained by cyclic voltammetry. This peak is related to the formation of Ag-oxides which were also observed in scanning electron microscopy images. At 100 % O2, the Tafel slope for Ag was 160 mV dec−1. For Pt above 0.8 V the slope was 75 mV dec−1. By decoupling the first proton- and electron-transfer step of an associative ORR mechanism, a theoretical model captures the Tafel-slope response of Pt when the first proton transfer is the rate-determining step (rds). If the electron transfer is the rds, the theoretical slope fits well with the Tafel behavior of Ag. In fuel cell conditions, Ag performs better than Pt below 0.5 V, but the stability of Ag is compromised above 0.8 V.

Inhomogeneous temperature distribution in a large-format lithium-ion cell or between cells in a module/pack may cause a non-uniform current distribution, causing a local difference in aging, and potentially faster global aging (capacity fade and impedance rise) of the module. To study this effect, LiNi1/3Mn1/3Co1/3O2/graphite lithium-ion pouch cells were cycled at 32, 36, and 40 degrees C as single cells and in parallel connection, representing uniform and non-uniform temperature distributions. The results show that the current distribution becomes less uniform after cycling at a higher rate and in a narrower state-of-charge range. Cycling with non-uniform temperature at 3C rate results in aging similar to that at the maximum uniform temperature, while at 1C rate the non-uniform aging follows the trend at the average temperature. The performance decay of the cells cycled at 3C is mainly driven by the cell at 40 degrees C which shows 30 % more capacity loss than the corresponding cell cycled singularly. This leads to additional considerations when designing for cycle life and reliability in fast charging applications and high-power applications such as in electric vehicles or frequency regulation in stationary storage.

To address the increasing demand for efficient, safe, and sustainable energy storage solutions in the transition towards renewable energy and electrified society, this study explores hybrid polymer-liquid electrolytes (HEs) as a novel solution to overcome challenges of traditional liquid electrolytes used in lithium-ion batteries (LIBs). Particularly, the research is focused on polymerization-induced phase separation (PIPS) synthesized HEs with distinct phase-separated systems, where an ion-conducting liquid phase percolates the macropores and mesopores within the formed thermoset solid phase. This study investigates the feasibility of using HEs with commercial cathodes and highlights their respective merits and challenges. The feasibility of infusing and forming HEs in commercial cathodes via PIPS within both micron-sized and nano-sized confined spaces is proved. By incorporating these HE-infused electrodes into half-cell configurations, the study proves that the HEs are compatible with common cathodes, and they exhibit energy density comparable with traditional systems with liquid electrolyte.

Laminated structural batteries present a transformative solution to reducing weight constraints in electric vehicles. These structural batteries are based on a multifunctional material that incorporates an energy storage function within a carbon fiber-reinforced polymer. Despite the potential of this technology, the intricate morphology of fiber-matrix or electrode-electrolyte interfaces and the impact of long-term cycling at low current rates (C-rates) on these interfaces remain insufficiently understood. This study addresses these critical knowledge gaps by examining the influence of matrix composition on the long-term electrochemical performance of structural battery electrodes and exploring advanced techniques to investigate carbon fiber-matrix interfaces. Localized imaging and X-ray scattering techniques were used to characterize morphological changes at the electrode-electrolyte interfaces by analyzing negative structural electrodes. The findings revealed that the matrix composition influences long-term electrochemical behavior and fiber-matrix interface formation. While the intrinsic properties of carbon fibers largely remain unaffected by long-term cycling, cycling promotes debonding at fiber-matrix interfaces. Nonetheless, residual regions of adhesion persist, underscoring the potential for preserving multifunctionality even under prolonged cycling conditions. These insights advance the understanding of interface dynamics, which is critical for optimizing structural battery technologies.

Ionomers based on poly(arylene piperidinium)s with varying ion exchange capacities are evaluated in different combinations of anode and cathode electrodes in anion exchange membrane fuel cells. The operational conditions are chosen with an asymmetrical regime including a dry anode with 50% relative humidity at the inlet, and full humidification at the cathode. Polarization and impedance measurements are carried out in potentiostatic steps within 0.3–0.9 V and distribution of relaxation times analysis is utilized to deconvolute resistance contributions. The results show that the best cell performance is achieved with both electrodes utilizing an ionomer with the highest ion exchange capacity (IEC) of 2.79 meq g −1 . Cells built exclusively from this ionomer achieved a peak power density of 1.01 W cm −2 . Deconvolution of the resistance contributions revealed the impact of water content on the effective charge transfer resistance in both electrodes and a diffusion resistance associated with the movement of water from anode to cathode side. The higher conductivity and water uptake of the high IEC ionomer resulted in a reduction of both resistance contributions, leading to the highest performance under the conditions evaluated. These findings provide important insights into how to tailor the electrode layers for optimum fuel cell output.

Although anion exchange membrane water electrolysis (AEMWE) shows promise for hydrogen production, the technology is still in the developmental phase. It faces substantial challenges, particularly concerning the long-term stability and durability of its components. A critical concern is the degradation of both the anion exchange membrane and the catalysts, which directly impact system performance and efficiency. This study investigates the degradation mechanisms of catalysts and membranes, with a focus on metal leaching, phase instability, and membrane thinning in AEMWE by investigating plasma-sprayed Ni 5 Fe 1 Mo 0.5 anode catalysts. Electrochemical assessments were performed in both full-cell and three-electrode configurations, followed by extensive post-test characterization to gain deeper insights into material degradation mechanisms. A key objective of this research paper is to highlight the importance of integrating electrochemical characterization, open-circuit voltage (OCV) monitoring, and post-test investigations to understand degradation pathways. While electrochemical performance indicators, such as polarization curves and high-frequency resistance (HFR), provide valuable operational insights, they do not fully capture the physical and chemical transformations and degradation that occur during cell operation. To address this gap, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX) was used for post-test analysis of both the catalytic layers and membranes extracted from full-cell tests, as well as catalyst layers from three-electrode tests. Post-test characterization revealed significant changes in the catalyst layer. Notably, metal leaching and catalyst particle detachment from the substrate PTL were observed, probably due to abrasion during oxygen evolution and possibly also metal leaching. Additionally, membrane thinning and localized catalyst detachment were also seen during extended operation times, correlating with OCV decline, reduced HFR, and low cell voltage at low current densities. Our hypothesis regarding the observed OCV drop was attributed to increased hydrogen crossover due to membrane thinning. In the three-electrode cell configuration, a more specific understanding of anode-specific degradation pathways can be obtained. Notable structural transformations and changes in surface composition of the anode catalyst were identified. Given the strong correlation between membrane thinning and OCV decline due to hydrogen crossover, some additional techniques, such as in-situ gas chromatography and the use of a hydrogen sensor on the anode side, are recommended for future studies. These findings highlight the complexity of evaluating AEMWE system degradation solely based on electrochemical performance metrics and underscore the need to integrate post-test characterization and hydrogen crossover measurement into the development process. This multifaceted analytical approach is crucial for advancing AEMWE technology, addressing key stability challenges, and guiding the future design of more robust catalysts and membranes.

Hydrogen offers a significant potential as an alternative to fossil fuels. It can also serve as a key input for various industrial processes, including fertilizer production, hydrogenation, hydrocracking, desulfurization, and more. By producing hydrogen through electrolysis using renewable energy sources, we can pave the way for a fossil-free future. From various types of electrolyzers around the world, Anion Exchange Membrane Water Electrolysis (AEMWE) is emerging as a promising technology by leveraging the advantages of Proton Exchange Membrane Water Electrolysis (PEMWE) and Alkaline water electrolysis (AWE). However, AEMWE technology is still in its developmental stages and requires more research to address durability and stability for long-term use. One critical aspect that warrants further investigation is catalyst development for AEMWE, specifically the use of non-critical and non-rare raw materials. Additionally, the stability of catalysts on the surface of electrodes poses another challenge. Studies indicate that nickel-based trimetallic alloys hold significant promise in this regard by improvements in catalyst activity and morphology on the surface of the catalyst particles. From different types of catalyst coating concepts, plasma spraying has shown potential for enhancing the stability of catalysts on electrode surfaces. This study aims to investigate the effects of plasma spraying on the stability of the catalyst on the electrode surface by utilizing PGM-free and non-critical materials. It involves using Ni 5 Fe 1 Mo 0.5 as an anode catalyst for AEMWE, which is prepared by applying plasma spray techniques on the surface of the substrate and comparing the electrochemical measurements and ex-situ tests with a commercial anode. To achieve this, a 1,200-hour accelerated stress test (AST) with dynamic and static current density has been performed in a 5 cm 2 electrolyzer test cell. For further analysis of the OER of the anode, Ni 5 Fe 1 Mo 0.5 was assessed in a three-electrode cell setup and compared with pristine stainless-steel fiber under different conditions. Furthermore, for a better understanding of the morphology of the anode catalyst and of the membrane, SEM-EDX was performed before and after the accelerated test. The electrochemical measurement results from the electrolyzer cell with Ni 5 Fe 1 Mo 0.5 anode showed better performance and lifetime compared with the benchmark. In addition, the impact of acceleration degradation from the AST procedure is noticeable, and we can observe its influence on degradation. However, a reduction in the polarization at low currents and in high-frequency resistance (HFR) could suggest that membrane thinning occurs in the cell. In addition, electrochemical measurement results from the three-electrode cell show better performance of Ni 5 Fe 1 Mo 0.5 compared to stainless-steel fiber. The morphology characterization, using SEM-EDX, demonstrated enhanced stability of the Ni 5 Fe 1 Mo 0.5 catalyst material on the PTL substrate compared with the benchmark. Further analysis of the membrane surface indicated degradation which also was supported by electrochemical measurements (see above). The study also illustrates the difficulties and complexity of analyzing AEMWE degradation only from electrochemical performance. Figure 1

Fast charging of electric vehicles remains a compromise between charging time and degradation penalty. Conventional battery management systems use experience-based charging protocols that are expected to meet vehicle lifetime goals. Novel electrochemical model-based battery fast charging uses a model to observe internal battery states. This enables control of charging rates based on states such as the lithium-plating potential but relies on an accurate model as well as accurate model parameters. However, the impact of battery degradation on the model’s accuracy and therefore the fitness of the estimated optimal charging procedure is often not considered. In this work, we therefore investigate electrochemical model-based aging-adaptive fast charging of automotive lithium-ion cells. First, an electrochemical model is identified at the beginning of life for 6 automotive prototype cells and the electrochemically constrained fast-charge is designed. The model parameters are then periodically re-evaluated during a cycling study and the charging procedure is updated to account for cell degradation. The proposed method is compared with two reference protocols to investigate both the effectiveness of selected electrochemical constraints as well as the benefit of aging-adaptive usage. Finally, post-mortem characterization is presented to highlight the benefit of aging-adaptive battery utilization.