Research progress on the poisoning behavior of air electrodes and corresponding protection strategies for protonic ceramic cells

As next-generation intermediate-temperature electrochemical energy conversion devices, protonic ceramic cells (PCCs) face significant challenges in durability and commercialization due to air electrode poisoning under complex operating conditions. This review provides a comprehensive summary of recent progress in the study of the poisoning of the air electrodes, focusing on the individual and synergistic mechanisms of various contaminants, including Cr species, CO 2 , high-temperature steam, and sulfides. The review also discusses strategies for improving the poisoning tolerance of air electrodes, such as doping, developing composite and high-entropy materials, surface modification and structural optimization. In addition, it highlights the application of advanced characterization techniques for elucidating poisoning processes and investigates the structure–function relationships between poisoning mechanisms and material design. Future research directions are identified to guide ongoing development. Overall, this review offers theoretical insights and technical guidance to advance high-performance, long-life air electrodes for PCCs.