Composite cathode based on Ni-loaded La0.75Sr0.25Cr0.5Mn0.5O3−δ for direct steam electrolysis in an oxide-ion-conducting solid oxide electrolyzer

Composite cathode based on La0.75Sr0.25Cr0.5Mn0.5O3−δ (LSCM) can be utilized for direct steam electrolysis in an oxide-ion conducting solid oxide electrolyzer; however, the insufficient electro-catalytic activity of LSCM still restricts the electrode performance and the Faraday efficiency. In this work, catalytic-active Ni particles are loaded to cathode via impregnation method. The electrical properties of LSCM are investigated and further correlated to the electrochemical performance of LSCM-SDC cathodes. The AC impedance spectroscopy and current-voltage tests demonstrate that the electrochemical reduction of LSCM cathodes is the main process at low voltages; however, the steam electrolysis is the dominant process at high voltages. The Faraday efficiency with Ni-loaded LSCM was enhanced by 20% in 4.96%H2/Ar/3%H2O and 11% in 97%Ar/3%H2O in contrast to the bare LSCM-SDC cathodes, respectively. The synergetic effect of catalytic-active Ni and redox-stable LSCM contributes to improved performance and the stability of the cathode for direct steam electrolysis.