Cobalt and Titanium substituted SrFeO3 based perovskite as efficient symmetrical electrode for solid oxide fuel cell

Abstract

One of the key tasks in solid oxide fuel cell research is to develop cost-competitive electrodes that work efficiently in wide range of air and fuel utilizations. Herein, we promote our study to a series of Cobalt and Titanium substituted La0.4Sr0.6Fe0.7Ti0.3-xCoxO3-δ (LSFTC, x = 0, 0.05, 0.1, 0.2) perovskite oxides. It is shown that Cobalt doping effectively improves the electrical conductivity and oxygen electrochemical reduction activity, yielding decreased cathode polarization resistance and lower dependence of pO2 change. For example, σ600°C = 81 S/cm and Rp,C750°C = 0.1 Ω cm2 for LSFTC-5 are obtained in pO2=0.21atm. In anode conditions of wet H2, the LSFTC cubic perovskites are partially reduced to hybrid structure of ABO3-A2BO4-metal with Cobalt doping amount less than 10% and are fully decomposed to A2BO4-metal with 20% doping. The higher Cobalt substitution generates more nano particles exsolution, which promotes anode processes at low temperatures. However, the generated AO-rich compositions are shown detrimental to anode performance in both conducting property and anode catalytic activity under low H2 partial pressures. In current study, the electrodes are evaluated under practical working conditions with broad pO2 and pH2, which provides guidelines for industrial-applicable SrFeO3 based symmetrical electrode development.