(???????)A hybrid catalyst coating for a high-performance and chromium-resistive cathode of solid oxide fuel cells

The electrocatalytic activity of oxygen reduction reaction on the cathodes of solid oxide fuel cells tends to be severely degraded due to the Cr poisoning effect ascribed to the use of a Fe-Cr alloy interconnect. Here, a hybrid catalyst coating consisting of BaCe0.8Gd0.2O3-delta and BaCO3 is developed on (La0.8Sr0.2)(0.95)MnO3+delta (LSM) cathodes to enhance the electrocatalytic performance and chromium tolerance. The hybrid catalyst coated LSM cell shows an excellent peak power density of 1.31 W cm(-2) at 750?degrees C, dramatically higher than 0.22 W cm(-2) of bare LSM cell. The hybrid catalyst coating also significantly enhances the operational stability of LSM cathodes under accelerated chromium poisoning conditions. The hybrid catalyst coating on the outermost electrode surface preferentially reacts with the Cr2O3 scale layer on the Fe-Cr interconnect to form conductive BaCrO4, and meanwhile the hybrid catalyst coating inside the electrode is inert to the gaseous Cr species, leading to remarkable Cr tolerance of the cathode. This work sheds light on the rational design of an efficient and durable LSM based cathode for solid oxide fuel cells.