Enhancing Active Surface Area and Gas Diffusion Properties of Low‐Temperature Solid Oxide Fuel Cell Cathodes by Sputtering with Glancing Angle Deposition

This paper reports an effective approach we have developed to sputter nanoporous single-phase La₀.₆Sr₀.₄Co₀.₂Fe₀.₈O₃-_δ (LSCF) thin-film cathodes using glancing angle deposition (GLAD), which leverages the self-shadowing effect to engineer nanocolumnar architectures with high porosity. By systematically tuning the sputtering pressure and film thickness, we achieved precise control over the cathode morphology, resulting in tunable porosity and triple-phase boundary (TPB) density. The GLAD-fabricated LSCF cathode deposited at 0.40 Pa exhibited a nanocolumnar porosity of 21.5%, compared to 7.5% for a conventionally sputtered LSCF film. At a thickness of 240 nm, this cathode achieved a polarization resistance of 6.4 Ω cm² at 500 °C, in contrast to 32.9 Ω cm² for its conventionally sputtered counterpart. Electrochemical analysis attributed this improvement to enhanced gas diffusion and surface exchange properties enabled by the nanocolumnar architecture. An anodized aluminum oxide (AAO)-supported thin-film SOFC (TF-SOFC) integrating the optimized GLAD-fabricated LSCF cathode (with yttria-stabilized zirconia (YSZ) electrolyte and nickel-yttrium doped ceria (YDC) anode) delivered a peak power density of 836 mW cm^- ² at 550 °C. These results establish GLAD sputtering as a promising strategy for engineering high-performance, nanoporous single-phase cathodes in LT-SOFC systems.