Electrochemical Investigation of La0.2Sr0.8TiO3+δ-Ce0.8Sm0.2O2-δ Composite Cathode for the Direct High Temperature Steam Electrolysis

This paper investigates a composite cathode La0.2Sr0.8TiO3+δ-Ce0.8Sm0.2O2-δ (LSTO-SDC) for the direct steam electrolysis in an oxide-ion-conducting solid oxide electrolyzer. The dependences of electrical conductivity of the reduced LSTO on temperature and oxygen partial pressure are studied and further correlated to the electrochemical properties of the cathode in symmetric cell LSTO-SDC/YSZ/LSTO-SDC and solid oxide electrolyzer LSTO-SDC/YSZ/LSM-SDC, respectively. Current efficiencies of the solid oxide electrolyzer with LSTO-SDC cathode were found to be 92.38% and 91.17% with or without reducing gas flowing over them under the applied voltage of 1.8 V at 800 °C, respectively.