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-delta (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%H-2/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 redoxstable LSCM contributes to improved performance and the stability of the cathode for direct steam electrolysis. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.