Nickel‐Regulated Composite Cathode with Balanced Triple Conductivity for Proton‐Conducting Solid Oxide Fuel Cells

Abstract Proton‐conducting solid oxide fuel cells (H‐SOFCs) have the potential to be a promising technology for energy conversion and storage. To achieve high chemical compatibility and catalytic activity, nickel‐doped barium ferrate with triple conducting ability is developed as cathodes for H‐SOFCs, presenting an impressive electrochemical performance at intermediate temperatures. The cell performance with the optimized BaCe 0.26 Ni 0.1 Fe 0.64 O 3 – δ (BCNF10) composite cathode reaches an outstanding performance of 1.04 W cm −2 at 600 °C. The high electrocatalytic capacity of the nickel‐doped barium ferrate cathode can be attributed to its significant proton conductivity which is confirmed through hydrogen permeation experiments. Density functional theory (DFT) calculations are further conducted to reveal that the presence of nickel can enhance processes of hydration formation and proton migration, leading to improve proton conductivity and electro‐catalytic activity.