Progress and challenges of electrolyte modulation in aqueous zinc-ion batteries

As a new type of green battery system,aqueous zinc-ion batteries(AZIBs)have gradually become a research hotspot due to their low cost,high safety,excellent stability,high theoretical capacity(820 mAh·g^(-1))of zinc anode,and low redox potential(-0.76 V vs.standard hydrogen electrode(SHE)).AZIBs have been expected to be an alternative to lithium-ion batteries for large-scale commercial energy storage applications.Unfortunately,they are facing thorny issues such as degradation of cycling performance,zinc dendrites,and side reactions.At the same time,these problems cause short cycling life of batteries,thus severely limiting their commercial application.In recent years,many more researches have been conducted on the modification of anode and cathode materials of AZIBs,but there is a lack of in-depth discussion on the characteristics and mechanism of electrolyte additives.In this review,we will make a systematic summary of the current problems with two electrodes in AZIBs,as well as the types and functions of electrolyte additives.Moreover,we further systematically describe the modulation mechanism of electrolyte additives in the performance of the cathode and anode.The prospects and development directions of additive modulation strategies for AZIBs electrolytes are prospected.