A review on advanced optimization strategies of separators for aqueous zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) are the most promising candidates for large-scale energy storage devices due to the advantages of low cost, high safety, environmental friendliness and high energy density. However, the low Coulombic efficiency (CE) and short cycle life of AZIBs caused by dendrite growth, hydrogen evolution reaction and corrosion of Zn anode, are limited the development and application of AZIBs in the future. To solve these problems, many works focused on the modification of Zn anode and electrolyte optimization have been widely reported. The separator–electrolyte interface and the separator–anode interface play a significant part in the behavior of zinc ions. Owing to the importance of separators for batteries, this paper reviews the requirements and optimization strategies of separators for AZIBs. It is mainly based on the surface modification of conventional separators (e.g. glass fiber, cellulose separators), the introduction of an intermediate membrane in the interlayer of the separator and anode, and the preparation of new-type separators to replace the conventional separators. In addition, this review proposes a further outlook on the future development of separators for AZIBs.