Investigation and study of three different composite cathodes for proton-conducting solid oxide fuel cells

• LSCF-LCO shows excellent cell performance and operation stability. • The composite cathode facilitates migration of protons and oxygen ions. • Triple conductivity is crucial to cathode reaction activity. Traditional composite cathode was usually mixed with cathode materials and BaZr 0.1 Ce 0.7 Y 0.2 O 3-δ (BZCY) to obtain thermal and chemical compatibility with proton-conducting electrolyte. Considering the poor chemical stability of BZCY under wet atmosphere, three different composite cathodes of La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3+δ (LSCF)-BZCY, LSCF-Sm 0.2 Ce 0.8 O 2-δ (SDC), LSCF-La 2 Ce 2 O 7+δ (LCO) were fabricated and systematically researched. Due to the high chemical stability and triple conductivity, the single cell with cathode of LSCF-LCO presented a better cell performance of 1020 mW·cm -2 at 700°C and long-term operation durability. In addition, the analysis of distribution of relaxation time method (DRT) and impedance spectrum revealed that the migration rate of proton and oxygen ion was enhanced through adjusting electrolyte material, showing great potential for future application of new cathode materials for proton-conducting solid oxide fuel cells (H-SOFCs).