This study introduces a polyacrylic acid (PAA) additive to gel electrolytes in aqueous zinc batteries, improving ionic diffusion and enabling uniform Zn deposition, which enhances battery reversibility. Zn||Mg_0.1V₂O₅ batteries with the modified electrolyte achieve 300 mAh g⁻¹ capacity at 0.5 A g⁻¹ and remain stable over 300 cycles, while batteries without PAA show rapid capacity decay.

Abstract

Gel electrolytes are widely used in aqueous zinc batteries to alleviate water-related issues. In this study, we develop a new gel electrolyte by introducing a small amount of polymer additive, inspired by electrolyte additives in liquid electrolytes. The introduction of polyacrylic acid (PAA) additive improves the ionic diffusion coefficient inside the gel electrolyte and enables uniform Zn deposition, enhancing the reversibility of Zn batteries. As a result, the Zn||Mg_0.1V₂O₅ batteries using the modified electrolyte show a maximum capacity of 300 mAh g⁻¹ at a current density of 0.5 A g⁻¹ and remain stable over 300 cycles. In contrast, the batteries without the PAA additive suffer from rapid capacity decay within 150 cycles under the same conditions. This study presents a simple and cost-effective method of gel electrolyte additive engineering to enhance the performance of aqueous zinc batteries.