Zein improved GF separator for dendrite-free aqueous zinc-ion batteries

Abstract

Aqueous zinc-ion batteries (AZIBs) have attracted widespread attention due to their advantages of intrinsic safety, low cost and eco-friendly nature. However, uncontrollable dendrite growth and side reactions of the zinc anode affect the cycle life of AZIBs, and traditional glass fiber separators are almost ineffective in inhibiting these issues. Here, a modified zein film was self-assembled in situ on a glass fiber surface through a simple, low-cost, and scalable strategy. The resulting ZLB-GF demonstrated good electrolyte wettability and mechanical strength. It was also conducive to uniform electrolyte electric field distribution and promoted uniform deposition of the zinc ions. Moreover, the zein molecules could adsorb on the zinc surface by their negatively charged groups, which inhibits the dendritic growth, and thus achieve a dendrite-free anode in a symmetrical cell. The symmetrical cell assembled with the ZLB-GF separator demonstrated stable cycling at 10 mA cm⁻² and 10 mA h cm⁻² for 3200 hours and 20 mA cm⁻² and 20 mA h cm⁻² for 1100 hours. Even more impressively, the Zn//MnO₂ full cell exhibited excellent stability. This scalable and effective strategy provides a new idea for practical applications of AZIBs.