Intermediate temperature solid oxide electrolysis cell using LaGaO3-base oxide

NiFe oxide composite was studied as cathode of steam electrolysis cell using LaGaO3 based oxide for electrolyte and it was found that H2 formation rate at 1.6V was much improved by combination of oxygen ion conducting oxide with NiFe (9:1) bimetallic alloy. In particular, a combination with La0.6Sr0.4Fe0.9Mn0.1O3 (LSFM) or Ce0.8Sm0.2O2 (SDC) is highly effective for increasing current density. Impedance plots for cathode consisted of two semicircles, which could be assigned to a diffusion and an activation overpotential in low and high frequency region, respectively. Compared with NiFe, mixing with SDC is much more effective for decreasing the diffusion overpotential. This might be assigned to increase in three phase boundary and porosity of cathode. ► We applied NiFe-oxide composite for cathode of steam electrolysis using LaGaO3 electrolyte. ► Cathodic performance was strongly affected by oxide combined with NiFe. ► Among the oxides, it was found that NiFe-SDC and NiFe-LSFM are highly active for cathodic reaction in steam electrolysis. ► Decrease in cathodic overpotential can be explained by improved diffusion process.