High-Performance Solid Oxide Fuel Cell with an Electrochemically Surface-Tailored Oxygen Electrode

Abstract

State-of-the-art cathodes for solid oxide fuel cells (SOFCs), such as (La,Sr)MnO3-(Y2O3)(0.08)(ZrO2)(0.92) (LSM-YSZ), suffer from sluggish oxygen reduction reaction (ORR) kinetics at reduced temperatures, leading to a significant decline in their performance. Herein, we report a tailored SOFC cathode with high ORR activity at intermediate temperatures using a simple but effective approach based on electrochemical surface modification. The proposed process involves chemically assisted electrodeposition (CAED) of a metal hydroxide (LaCo(OH)(x)) on LSM-YSZ surfaces followed by insitu thermal conversion of LaCo(OH)(x) to perovskite-type LaCoO3 (LCO) nanoparticles during the SOFC startup. This method facilitates easy loading of the LCO nanoparticles with a precisely controlled morphology without the need for repeated deposition/annealing processes. An anode-supported SOFC with the LCO-tailored LSM-YSZ electrode exhibits a remarkably increased power density, approximately 180% at 700 degrees C, compared with an SOFC with the pristine electrode as well as excellent long-term stability, which are attributed to the beneficial role of the CAED-derived LCO nanoparticles in enlarging the active areas for ORR and promoting oxygen adsorption/diffusion. This work demonstrates that controlled surface tailoring of the cathode by CAED could be an effective approach for improving the performance of SOFCs at reduced temperatures.