High-Entropy Perovskite Oxide: A New Opportunity for Developing Highly Active and Durable Air Electrode for Reversible Protonic Ceramic Electrochemical Cells

Highlights Synthesis of high-entropy perovskite oxide for air electrode in reversible proton ceramic electrochemical cells. Triple-conducting high-entropy air electrodes exhibit excellent structural stability and oxygen catalytic activity. The peak power density and current density of the cell with high-entropy air electrode in the fuel cell and electrolysis modes are 1.21 W cm −2 and − 1.95 A cm −2 at 600 °C, respectively.