Proton storage chemistry in aqueous zinc-organic batteries: A review

Abstract

Benefiting from the advantageous features of structural diversity and resource renewability, organic electroactive compounds are considered as attractive cathode materials for aqueous Zn-ion batteries (ZIBs). In this review, we discuss the recent developments of organic electrode materials for aqueous ZIBs. Although the proton (H+) storage chemistry in aqueous Zn-organic batteries has triggered an overwhelming literature surge in recent years, this topic remains controversial. Therefore, our review focuses on this significant issue and summarizes the reported electrochemical mechanisms, including pure Zn2+ intercalation, pure H+ storage, and H+/Zn2+ co-storage. Moreover, the impact of H+ storage on the electrochemical performance of aqueous ZIBs is discussed systematically. Given the significance of H+ storage, we also highlight the relevant characterization methods employed. Finally, perspectives and directions on further understanding the charge storage mechanisms of organic materials are outlined. We hope that this review will stimulate more attention on the H+ storage chemistry of organic electrode materials to advance our understanding and further its application. (Figure presented.).