Polyhydroxy Starch with Abundant Hydroxyl and Unique Structure Enables Uniform Zn Deposition

Abstract

Zinc metal is a promising anode material for zinc-ion batteries (ZIBs), but severe side reactions and dendrite formation hinder its commercialization. In this study, starch is introduced into the ZnSO4 electrolyte for stabilizing the Zn anode. With abundant hydroxyl groups, starch can reconstruct the H-bonds system in the electrolyte, suppressing side reactions. Moreover, the unique ring and double-helix structures of starch show strong interactions with Zn²⁺ ions. The large molecule structure also exhibits a steric hindrance effect, regulating the diffusion and reduction of Zn2+. Additionally, starch molecules can adsorb onto the Zn anode, promoting the formation of a solid-electrolyte interphase (SEI) and resulting in uniform Zn deposition along the (002) plane. Consequently, this approach enhances the stability and reversibility of the Zn anode.