High- and low- temperature behaviors of La0.6Sr0.4Co0.2Fe0.8O3−δ cathode operating under CO2/H2O-containing atmosphere

High- and low- temperature behaviors of La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) cathode for solid oxide fuel cells operating under CO2/H2O-containing atmosphere are investigated. LSCF shows different stability against CO2 and H2O at high and low temperature. LSCF has excellent electrochemical performance and high stability against the corrosion of CO2 and H2O at 750 °C due to weak reactivity of LSCF with CO2. LSCF shows a serious degradation at 600 °C under operation with O2–CO2(2.83%)–H2O(2.64%), which is ascribed to the impeded oxygen activation and oxygen surface diffusion by surface carbonates and SrCO3 phases on LSCF surface. Under CO2(5%)–H2O(2.81%)–He, LSCF reacts with CO2 to yield SrCO3 phases in 400–680 °C, and H2O aggravates the chemical reaction between CO2 and LSCF. Taking into account of SrCO3 phase formation on LSCF, LSCF cathode is stable under operation with O2–CO2(2.83%)–H2O(2.64%) in 680–800 °C, whereas it is unstable below 680 °C. LSCF can be subject to degradation caused by CO2 and H2O in air during long-term operation below 680 °C.