Electrolyte/electrode interfacial electrochemical behaviors and optimization strategies in aqueous zinc-ion batteries

Aqueous zinc-ion batteries (ZIBs) are considered as a promising alternative for the large-scale energy storage due to the environmental friendliness, low cost, intrinsic safety. However, there are still many scientific and technical issues that have not been revealed, particularly the fundamental understanding of electrolyte/electrode interfacial electrochemical behaviors, which can profoundly affect the electrochemical performance of aqueous ZIBs. Research interests and achievements in ZIBs have been extensively discussed and reviewed in recent years, but the comprehensive discussion and perspectives in the interfacial chemistry at electrode/electrolyte interface (EEI) are still in the incipient stage. Specially, the reaction mechanism and behaviors of the cathode/electrolyte interface and its effect on electrochemical performance have rarely been reviewed. Therefore, it is of great significance for developing a systematic and thorough understanding on the ionic electrochemical behaviors for interfacial reactions, which will guide the fundamental research and further practical application. In this review, we particularly focus on the characteristics and formation mechanism of EEI, the various ionic electrochemical behaviors at EEI and interfacial optimization strategies on cathode and anode. The final section proposes the practical considerations in manipulating EEI in aqueous ZIBs, and future perspectives in this field for the development of ZIBs.