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_0.8Ba_0.2CoO₃ (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–xA′_xBO₃ (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 cm² at 600 °C) is achieved, because LBC can significantly facilitate the formation of O₂^*. This work not only reports an effective air electrode but also presents a new avenue for the rational design of air electrodes for PCCs.