The protective effect and its mechanism for electrolyte additives on the anode interface in aqueous zinc-based energy storage devices

Aqueous-electrolyte-based zinc-ion batteries (ZIBs), which have significant advantages over other batteries, including low cost, high safety, high ionic conductivity, and a natural abundance of zinc, have been regarded as a potential alternative to lithium-ion batteries (LIBs). ZIBs still face some critical challenges, however, especially for building a reversible zinc anode. To address the reversibility of zinc anode, great efforts have been made on intrinsic anode engineering and anode interface modification. Less attention has been devoted to the electrolyte additives, however, which could not only significantly improve the reversibility of zinc anode, but also determine the viability and overall performance of ZIBs. This review aims to provide an overview of the two main functions of electrolyte additives, followed by details on six reasons why additives might improve the performance of ZIBs from the perspectives of creating new layers and regulating current plating/stripping processes. Furthermore, the remaining difficulties and potential directions for additives in aqueous ZIBs are also highlighted.