Balancing the triple conductivity of zinc-doped cathodes for proton-conducting solid oxide fuel cells

One of the current research directions in proton-conducting solid oxide fuel cells (H-SOFCs) is the development of triple-phase conducting cathodes. To enhance the proton conductivity and catalytic activity of barium ferrate cathode materials, the ratio of cerium to zinc is optimized, and the phase composition is carefully adjusted. This optimization results in significantly improved power density in single cells utilizing BaCe0.26Fe0.64Zn0.1O3-delta (BCFZ10) as the cathode, reaching a peak power density of 998.6 mW cm-2 at 600 degrees C. The remarkable performance of BCFZ10 cells can be attributed to their heightened proton conductivity and diminished hydration energy, as validated by thermogravimetric (TG) experiments. Density functional theory (DFT) calculations have further substantiated that the incorporation of zinc through doping effectively lowers the energy barrier for proton transition, consequently amplifying the proton absorption capability and electrochemical reactivity. The Zn-doped BCF36 cathode boosts proton conductivity, lowers hydration energy and achieves a peak power density of 998.6 mW cm-2 at 600 degrees C with a polarization resistance of 0.151 Omega cm2 for a single cell with the BCFZ10 cathode.