Strategies for enhancing proton conductivity in perovskites: A review

Proton-conductive perovskite materials are promising platforms for advanced electrochemical devices, including fuel cells, electrolyzers, and sensors, due to their mixed ionic–electronic transport properties. However, their practical application remains limited by inadequate proton conductivity and insufficient long-term stability. This review critically analyzes recent material optimization strategies to address these challenges. Defect engineering via aliovalent doping is identified as a key approach to increase oxygen vacancy concentration, thereby enhancing proton incorporation and transport. Surface modification is shown to improve interfacial properties while suppressing degradation mechanisms. Strategies for stability optimization are examined in terms of resistance to chemical, thermal, and mechanical stress. In addition, nanostructuring is demonstrated to shorten diffusion pathways and increase active surface area, facilitating proton transport. These approaches are evaluated in relation to both Grotthuss and vehicle proton conduction mechanisms. Overall, this review establishes a clear structure–property–performance relationship to guide the rational design of durable, high-performance proton-conductive perovskites for next-generation electrochemical systems.