Aramid Nanofiber and Lithium Acetate Synergistically Regulated Gel Polymer Electrolyte for Stable Zinc-Ion Batteries

Abstract

The practical application of aqueous zinc-ion batteries (AZIBs) is hindered by the interfacial parasitic reactions induced by free water and sluggish kinetics arising from the strong solvation effect of Zn²⁺. Herein, we develop a gel polymer electrolyte (GPE) design strategy that synergistically reconstructs the solvation structure and hydrogen bond network by integrating aramid nanofibers (ANF) and lithium acetate (LiOAc) into a polyacrylamide matrix. The carbonyl groups (–C=O) in ANF and polyacrylamide competitively coordinate with Zn²⁺, weakening cation–dipole interactions and providing additional hopping sites for Zn²⁺ transport. Amino groups in ANF anchor anions to enhance the Zn²⁺ transference number, while restricting free water activity by hydrogen bonding. LiOAc shifts OAc^––Zn²⁺ coordination toward a more asymmetric, monodentate-like configuration, in which the exposed –C=O oxygen confines free water. With this GPE, Zn||Cu cells achieve an average Coulombic efficiency of 99.6%, Zn||Zn symmetric cells operate stably for over 2800 h, and Zn||PANI full cells exhibit durable cycling stability. This synergistic regulation of the solvation structure and hydrogen-bond network accelerates Zn²⁺ transport, suppresses parasitic reactions, and stabilizes zinc deposition, thereby significantly advancing the design of high-performance GPEs for zinc-ion batteries.