High-Entropy Electrolyte for Scalable Zinc–Iodine Flow Batteries
Shimeng Zhang, Yu Wu, Jianxiong Gao, Zhilong Wang, Yanyun Song, Xinyu Zhao, Ju Xiao, Bowen Jin, Mingfei Shao
Abstract
Zinc metal anodes offer high capacity and intrinsic safety for aqueous batteries but are limited by sluggish interfacial desolvation and dendrite-induced instability under high utilization. Here, we design a high-entropy aqueous electrolyte by introducing multiple water-affine, low-molecular-weight alcohols at a fixed additive content, enabling solvent diversity to be tuned independently of concentration. Temperature-dependent transport analysis and electrochemical characterizations reveal entropy-assisted Zn 2+ desolvation with a reduced activation barrier and a cleaner electrode–electrolyte interface, as evidenced by minimal solvent retention during deposition. This entropy-enabled interfacial regulation promotes preferential Zn (002) growth, suppresses parasitic reactions, and improves plating/stripping reversibility. When applied in a Zn–I 2 flow battery, the electrolyte delivers a volumetric anodic capacity of 1905 mAh cm –3 in a 100 cm 2 cell, together with high Coulombic and energy efficiencies. This work demonstrates entropy engineering of solvent environments as a strategy for stabilizing zinc metal anodes in scalable aqueous energy storage systems.