Utilizing High Entropy Effects for Developing Chromium‐Tolerance Cobalt‐Free Cathode for Solid Oxide Fuel Cells

Abstract Solid oxide fuel cell (SOFC) is regarded as an environmentally friendly energy conversion device, which can directly convert the chemical energy stored in the fuel to the electrical energy. However, the degradation of cathodes caused by Cr‐containing steel interconnects is a major problem that limits the broader application of SOFC. Herein, a novel A‐site high entropy oxide, based on the cobalt‐free PrBaFe 2 O 5+ δ (PBF) cathode, La 0.2 Pr 0.2 Nd 0.2 Sm 0.2 Gd 0.2 BaFe 2 O 5+ δ (LPNSGBF), is proposed as a high catalyst activity and Cr‐tolerance cathode for SOFC. The anode‐supported cell with the LPNSGBF cathode exhibits an excellent peak power density of 1020.69 mW cm −2 at 800 °C, which is better than that of the PBF (794.96 mW cm −2 ). Moreover, under the Cr‐containing atmosphere, the outstanding stability of the single cell with the LPNSGBF for 100 h with a degradation rate of 0.17% h −1 , is much lower than the 0.79% h −1 for that of the PBF cathode. The study provides a new strategy for achieving the enhanced oxygen reduction reaction and high Cr‐tolerance of the cobalt‐free cathode by high entropy doping.