High-Acceptor Fluoroalcohol Mediated Anion-Solvation Enables Durable Zn-V Batteries

Aqueous zinc batteries (AZBs) are promising low-cost and safe energy storage devices, yet suffer from dendrite growth and parasitic reactions caused by H₂O-rich solvation structure in conventional electrolytes. While high donor number (DN) co-solvent strategies effectively reduce the H₂O molecules in Zn²⁺ inner solvation sheath, they fail to facilitate Zn²⁺ migration or de-solvation. Herein, an anion-solvation strategy using a high acceptor number (AN) co-solvent, 2,2,3,3-tetrafluoro-1-propanol (TFP), is proposed to address these challenges. Rationally, TFP with high AN strongly promotes TFP-anion and TFP-H₂O interactions while reducing their interaction with Zn²⁺, leading to a H₂O-poor Zn²⁺ solvation sheath, which not only enhances Zn²⁺ transference number and de-solvation kinetics but also lowers H₂O activity to suppress parasitic reactions and cathode dissolution. Hence, this anion-solvation electrolyte bestows highly reversible Zn plating/striping over 9000 h with a high Coulombic efficiency of 99.8%. The Zn-V full cell delivers outstanding cycling performance, maintaining 98.8% capacity after 200 cycles at 0.25 A g^-1 and 96.3% capacity after 900 cycles at 1 A g^-1. This anion-solvation strategy opens up a new frontier in electrolyte developments toward high-performance aqueous batteries.