Investigation of effects of co doping on the electrochemical behaviour of double pervoskite oxide Sr2MgCrO6-δ as an anode material for solid oxide fuel cells

Double-perovskite materials of composition Sr2Mg1−xCoxCrO6−δ (SMCCO, x = 0 to 0.7) were evaluated as potential SOFC anode materials. Their lattice structures, electrical and ionic conductivity, and electrochemical performance were investigated to study the effect of Co content. SMCCO also showed good chemical compatibility at temperatures below 1000 °C. Both the electronic and ionic conductivity increased with increasing Co doping. To investigate the effect of Co doping on the conduction properties of SMCCO, we performed first-principle calculations. From these results, we found that the weak Co−O bond is considered to be responsible for the enhanced ionic conductivity of SMCCO materials. The substitution of Co was also found to increase the sinterability of SMCCO, resulting in a decrease in the polarization resistance of the SMCCO electrode. Single-cell tests indicated the potential ability of the Co-doped SMCO to be used as SOFC anodes.