Rationally Designed Air Electrode Boosting Electrochemical Performance of Protonic Ceramic Cells

Abstract Protonic ceramic cells (PCCs) have gained significant attention as a promising electrochemical device for hydrogen production and power generation at intermediate temperatures. However, the lack of high‐performance air electrodes, specifically in terms of proton conduction ability, has severely hindered the improvement of electrochemical performances for PCCs. In this study, a high‐efficiency air electrode La 0.8 Ba 0.2 CoO 3 (LBC) is rationally designed and researched by a machine‐learning model and density functional theory (DFT) calculation, which boosts the performances of PCCs. Specifically, an elements‐property map for designing high‐efficiency oxides is created by predicting and studying the proton uptake ability of La 1– x A′ x BO 3 (A′ = Na, K, Ca, Mg, Ba, Cu, etc.) by an eXtreme Gradient Boosting model. PCC with LBC air electrode yields high current destiny in electrolysis mode (1.72 A cm −2 at 600 °C) and power density in fuel cell mode (1.00 W cm −2 at 600 °C). In addition, an ultra‐low air electrode reaction resistance (0.03 Ω cm 2 at 600 °C) is achieved, because LBC can significantly facilitate the formation of O 2 * . This work not only reports an effective air electrode but also presents a new avenue for the rational design of air electrodes for PCCs.