Effects of manganese substitution at the B-site of lanthanum-rich strontium titanate anodes on fuel cell performance and catalytic activity

Sr_0.4La_0.6Ti_1-xMn_xO _3-δ with rhombohedral structure has been investigated in terms of their electrochemical performance, redox stability, and electro-catalytic properties for solid oxide fuel cell anodes. The performance of Sr _0.4La_0.6Ti_1-xMn_xO _3-δ anodes for solid oxide fuel cells strongly depends on the Mn substitution at the B-site of the perovskites. Electrical conductivity of Sr_0.4La_0.6Ti_1-xMn_xO _3-δ increases with increasing Mn content. X-ray photoelectron spectroscopy analysis reveals that the amount of Mn³⁺ and Ti ³⁺, which is an electronic charge carrier, increases with Mn doping. The reduced anode powders with high Mn/Ti ratio show oxygen storage capability and a low carbon deposition rate. Linear thermal expansion coefficients of Sr_0.4La_0.6Ti_1-xMn_xO _3-δ anodes range from 9.46×10^-6 K^-1 to 11.3×10^-6 K^-1. The maximum power densities of the single cell with the Sr_0.4La_0.6Ti_0.2Mn _0.8O_3-δ anode in humidified H₂ and CH₄ at 800 °C are 0.29 W cm^-2 and 0.24 W cm ^-2, respectively.