A cobalt-free Sm0.5Sr0.5FeO3−δ–BaZr0.1Ce0.7Y0.2O3−δ composite cathode for proton-conducting solid oxide fuel cells

A cobalt-free Sm0.5Sr0.5FeO3−δ–BaZr0.1Ce0.7Y0.2O3−δ (SSF–BZCY) was developed as a composite cathode material for proton-conducting solid oxide fuel cells (H-SOFC) based on proton-conducting electrolyte of stable BZCY. The button cells of Ni-BZCY/BZCY/SSF–BZCY were fabricated and tested from 550 to 700 °C with humidified H2 (～3% H2O) as a fuel and ambient oxygen as oxidant. An open-circuit potential of 1.024 V, maximum power density of 341 mW cm−2, and a low electrode polarization resistance of 0.1 Ω cm2 were achieved at 700 °C. The experimental results indicated that the SSF–BZCY composite cathode is a good candidate for cathode material.

► The button cells were fabricated with the thickness of BZCY membrane only 20 μm. ► The maximum peak power density was 341 mWcm−2 and the interfacial polarization resistance Rp was 0.1 Ωcm2 at 700 °C. ► The activation energies of composite cathode for Rp, RH and RL are calculated as 0.66, 0.60 and 0.67 eV, respectively.