Low catalyst loading and process-integrated electrode fabrication are important for reducing material demand and manufacturing complexity in anion-exchange membrane water electrolysis (AEMWE). Here, Ni and NiMo hydrogen-evolution cathodes are fabricated by direct-current magnetron sputtering, enabling direct catalyst deposition onto the electrode substrate without separate catalyst-powder synthesis, ink formulation, or post-deposition thermal treatment. On planar substrates, decreasing sputter power and increasing Ar pressure shifts film growth toward a rougher, more open columnar morphology and increases the electrochemically accessible surface area. Transfer of the optimized process to porous carbon paper yields catalyst loadings of 0.03–0.13 mg/cm2 for Ni and 0.04–0.21 mg/cm2 for NiMo, with cross-sectional SEM-EDX showing preferential catalyst localization in the membrane-facing region of the substrate. The NiMo200 cathode, containing only 0.14 ± 0.02 mgNiMo/cm2, reaches 1 A/cm2 at 1.95 V and 60 °C and 1.88 V at 80 °C in a fully PGM-free AEM electrolyzer with an uncoated stainless-steel anode. This corresponds to a cathode-mass-specific current density of 7.1 ± 1 A/mgNiMo. During 500 h operation at 1 A/cm2, the cell reaches 2.00 V and a late-stage degradation rate of 10 ± 7 μV/h. A Pt-cathode control with the same stainless-steel anode exhibits a similar degradation profile and late-stage rate, suggesting that NiMo-specific degradation is comparable to that of Pt and is largely masked by degradation contributions from other components of the assembly. The results demonstrate magnetron sputtering as a material-efficient, solvent- and ionomer-free route to low-loading AEMWE cathodes while highlighting electrode cross-contamination and long-term catalyst evolution as remaining challenges.
Smart battery cells have been proposed to improve the safety of lithium-ion battery packs in Battery Electric Vehicles (BEVs) and Battery Energy Storage Systems (BESSs). Powerline Communication (PLC) offers a cable-free, scalable solution for smart cell systems, enabling key battery parameters, including temperature, voltage, and current, to be transmitted through existing electrical connections. This paper proposes a large-scale series-connected cylindrical battery-based PLC channel simulation model. Simulation results for 1S1P, 5S1P, and 8S1P configurations show excellent agreement with Vector Network Analyser measurements, validating the model. The model is then extended to 50S1P, 200S1P, 400S1P, and 1200S1P, to assess the effect of scale on PLC performance. The reconstructed channel responses are used to evaluate Bit Error Rate (BER) performance under Signal-to-Noise Ratio (SNR) conditions. The results show that 200S1P and 400S1P packs maintain reliable communication at 20 dB SNR, whereas the 1200S1P configuration suffers degradation even at 25 dB. To achieve a BER of 1 × 10−5, the 1200S1P, 400S1P, and 200S1P configurations require additional SNR margins of 15.751 dB, 9.602 dB, and 5.927 dB, respectively, compared with 1S1P. These findings demonstrate the feasibility of PLC for high-voltage battery systems, while highlighting the challenges of ultra-large packs for future BESSs.
Thick Ni-rich NMC (LiNixCoyMnzO2, x > 90 mol%) cathodes are a promising route towards high energy density lithium-ion batteries but suffer from poor ionic transport, resulting in limited rate capability and accelerated degradation. Although laser structuring has emerged as an effective strategy to improve electrolyte transport, its application to thick high-nickel cathodes has not been systematically investigated, particularly regarding the influence of structuring geometry on electrochemical performance and transport properties. Here, femtosecond laser structuring was applied to conventional and thick single-crystal NMC90 (LiNixCoyMnzO2, x = 90 mol%) cathodes using three different pattern spacings to establish the relationship between electrode architecture, rate capability, cycling stability, and effective through-plane tortuosity. Laser structuring significantly enhanced high-rate half-cell performance without inducing thermal damage to the active material. Structured thick electrodes exhibited high discharge capacity at 3C together with improved cycling stability, while electrochemical impedance spectroscopy revealed reductions in ionic resistance and effective tortuosity exceeding 65–70% compared with unstructured electrodes. These findings demonstrate that femtosecond laser structuring effectively overcomes the transport limitations of thick Ni-rich cathodes, providing practical design guidelines for high-energy lithium-ion batteries.
Herein, the electrochemical performance of LiFePO4 (LFP) electrodes is studied in electrolytes containing different LiFSI concentrations at room temperature and 40 °C, with upper cut-off potentials up to 5.0 V vs. Li+/Li. LFP-Li half-cells containing 1.0 M LiFSI exhibited stable cycling for more than 250 cycles at 4.0 V but failed rapidly when cycled to 5.0 V vs. Li+/Li. This effect is attributed to the anodic dissolution (corrosion) of the aluminum current collector due to solvent oxidation yielding protons. In contrast, LFP-graphite full-cells enabled reversible cycling up to about 5.0 V (i.e., about 4.9 V vs. Li+/Li) when the LiFSI concentration was increased to about 2.0 M. One possible reason for this improvement is the formation of fluoride-based passive surface layer(s) preventing corrosion upon increasing the LiFSI concentration, as previously seen in 1.0 M LiPF6. This hypothesis is further supported by results obtained with electrolytes containing both LiFSI and LiPF6. At 40 °C and a 1C-rate, LFP-graphite full-cells containing 2.0 M LiFSI showed higher capacity retention than LiPF6-based systems, possibly due to the increased LiPF6 decomposition at 40 °C. These results demonstrate that electrolytes containing 2.0 M LiFSI can be used in LFP-graphite cells cycled up to 5.0 V.
This study presents a multilayer TiO2/Ni/Ag cathode designed to improve its stability and increase the efficiency of molten carbonate fuel cells (MCFCs). The architecture consists of a tape-cast porous nickel catalytic layer supported by nickel foam, providing mechanical stability. A TiO2 coating was selectively electrophoretic deposited on the electrolyte-facing side to suppress nickel dissolution in the molten carbonate electrolyte, which is one of the main degradation mechanisms in MCFCs. Additionally, a 300 nm silver layer was sputtered onto the current collector side to reduce charge transport resistance, thereby improving fuel cell performance. Microstructural uniformity and chemical compatibility were confirmed by SEM/EDX analysis, while phase stability was verified by XRD. Nickel solubility in the molten electrolyte was quantified under realistic cathode operating conditions using a dedicated experimental protocol. Single-cell tests performed at 650°C under various gas flow rates, supported by electrochemical impedance spectroscopy, demonstrated a clear positive effect of the dual modification. The TiO2 layer reduced nickel dissolution twice. Additional silver coating resulted in a 67% increase in power density compared to an unmodified cathode. At the same time, material consumption is reduced by limiting the use of functional layers to only where they are most needed.
