Progress of electrode materials for aqueous proton batteries

Abstract The global pursuit of clean and sustainable renewable energy emphasizes the necessity for advanced energy storage systems. Researchers in this field aim to develop devices that integrate the high‐energy density of batteries with the rapid charge and discharge rates characteristic of capacitors. Protons, due to their small size and efficient diffusion via Grotthuss conduction mechanism, serve as particularly advantageous charge carriers for ultrafast intercalation and deintercalation in aqueous batteries. This property has led to the development of a novel energy storage device defined as the aqueous proton battery (APB), which holds the potential to establish a distinct position within the energy storage landscape. This article offers a comprehensive review of recent advancements in electrode materials and battery configurations specifically designed for APBs. The fundamental principles of electrochemical proton storage and detailed insights into Faradaic APB electrodes are highlighted, while the associated challenges regarding their electrochemical performance and operational mechanisms are emphasized. Additionally, the strategic design approaches for full‐battery systems aimed at achieving high‐performance aqueous proton energy storage are summarized. Finally, the challenges and potential opportunities for further enhancing the applications of APBs are proposed.