(La,Sr)(Cr,Mn)O3/GDC cathode for high temperature steam electrolysis and steam-carbon dioxide co-electrolysis

A composite of (La,Sr)(Cr,Mn)O3/(Gd,Ce)O2 (LSCM/GDC) was evaluated as a cathode in a high temperature solid oxide electrolysis cell (SOEC) used for steam electrolysis and/or steam-carbon dioxide co-electrolysis. When the steam feed rate was smaller than 30 ml/min, the LSCM/GDC cathode is subject to large diffusion resistance from inadequate steam supply at steam concentration of 3–20%. Sigmoidal shaped I–V curves were thus observed for steam electrolysis, unlike when CO2 was present during reduction where smooth I–V characteristics were observed. With respect to steam-carbon dioxide co-electrolysis, the LSCM/GDC cathode showed lower performance than for CO2 electrolysis, due to insufficient steam content at a feed of 20% H2O–5% H2/Ar (10 ml/min) and CO2/CO 70/30 (20 ml/min) mixture.