Electrolyte Regulation Methods for Improving the Cycle-Life of Zinc Metal Anodes

Aqueous zinc-ion batteries (AZIBs) are promising candidates for large-scale energy storage systems as their high safety, environmentally-friendly, and low-cost. Nevertheless, the hydrogen evolution reaction, corrosion reactions, and dendrite growth on the zinc metal anode severely hindered the commercialization of AZIBs. In recent years, numerous reports have demonstrated that the above issues can be effectively and cost-efficiently resolved through electrolyte regulation. The electrolyte in the batteries can be classified as bulk electrolyte and electrolyte double layer (EDL) electrolyte. Additionally, the solid electrolyte interphase (SEI) formation on the zinc metal anode is significantly affected by the composition and properties of the electrolyte. However, a complete macroscopic insight into the diverse electrolyte design methods related to the three aforementioned aspects is still lacking. Herein, after thoroughly explaining the fundamental issues associated with zinc metal anodes in aqueous electrolytes, we provide a detailed summary of three electrolyte regulation methods: solvation structure regulation, which addresses the bulk electrolyte; EDL regulation, which focuses on the EDL electrolyte; and SEI regulation, which targets the SEI. Additionally, an overview of prospective research directions in the development of electrolyte regulation methods is offered. This review aims to serve as a reference for researchers in future electrolyte design.