A Highly Stable and Active Hybrid Cathode for Low-Temperature Solid Oxide Fuel Cells

Improving the sluggish oxygen reduction reaction (ORR) is vital to enable the commercialization of some high-temperature clean-energy devices. Silver (Ag) is usually decorated onto the surface of electrodes to enhance ORR activity. However, the thermal instability of Ag causes the deactivation of ORR on coarsened particles under operating conditions. Here, we introduce a SrSc_0.175Nb_0.025Co_0.8O_3-δ (SSNC) perovskite hybrid cathode decorated with Ag@CeO₂ core-shell spheres, which shows an extremely high performance for the ORR. Its area-specific resistance is just 0.24Ωcm² at 500°C, and it works stably under a cathodic polarization at 600°C for over 110h, without detectable performance deterioration. Electron microscopy reveals that the Ag cores remain isolated even after heating the catalyst to 800°C. The design concept in this work can be extended to prevent the aggregation of other metallic electrocatalysts working at high temperatures.