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

Abstract

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, by optimizing the ratio of cerium and zinc and adjusting the phase composition, improved power density is achieved in the single cell with BaCe0.26Fe0.64Zn0.1O3-δ (BCFZ10) as cathode, reaching a peak power density of 998.6 mW cm-2 at 600°C. The remarkable performance of BCFZ10 cells can be attributed to their heightened proton conductivity and diminished hydration energy, as validated by thorough thermo gravimetric (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.