Insights into host materials for aqueous proton batteries: structure, mechanism and prospect

Rechargeable energy storage devices have been widely applied to meet the development of social green economy storage. Aqueous proton batteries (APBs) are regarded as one of the most promising energy storage devices for the next-generation batteries, benefiting from its reliable safety and reasonable profitability. The non-metallic charge carriers migrate faster through the continuous water chain and exhibit considerable conductivity at low temperatures in APBs. In this review, the recent investigations on APBs are comprehensively summarized from different energy storage mechanisms, hydrogen insertion/extraction reaction, chemical conversion reaction and catalytic hydrogen evolution/oxidation reaction. Based on these reaction mechanisms, the specific structures required for the host materials are concluded. In the end, the existing problems and future development of APBs are reported. [Display omitted] •Recent progress of aqueous proton batteries is summarized.•Different reaction mechanisms in aqueous proton batteries are classified.•Required chemical structures of host materials are reported for proton storage.•The future development direction of aqueous proton batteries is proposed.