(La0.75Sr0.25)0.95Mn0.5Cr0.5O3 as the cathode of solid oxide electrolysis cells for high temperature hydrogen production from steam

Abstract

Ni/YSZ cathodes are generally utilised for steam electrolysis; however such electrodes can only operate under reducing conditions. In an atmosphere with low content of H₂ or without H₂, especially under low current conditions, cathodes based on (La_0.75Sr_0.25)_0.95Mn_0.5Cr_0.5O₃ (LSCM) provide a promising alternative. Solid Oxide Electrolysis Cells with LSCM cathodes were tested under external potential load at temperatures between 750 °C and 1000 °C using 3% steam/Ar/4% H₂ and 3% steam/Ar, and promising polarisation impedance data were obtained in both atmospheres, especially in the gas without H₂. I–V curves from LSCM cells in 3% steam/Ar have sigmoidal shape indicative of chemical changes in the LSCM occurring in addition to electrolysis. Despite these features, considerably improved performance is found compared to Ni-based electrodes in low hydrogen conditions.