Chelating additive enabled dual-action hydrogel polymer electrolyte: suppressing dendrite formation and crosstalk in aqueous rechargeable zinc metal batteries

Abstract

Aqueous rechargeable zinc metal batteries (ARZMBs) have garnered significant attention as a sustainable energy storage solution offering high capacity, cost-effectiveness, and ecofriendliness. However, challenges such as uncontrolled zinc dendrite formation and inter-electrode crosstalk hinder their electrochemical stability and long-term cycling performance. In this work, we developed a dual-function gel electrolyte incorporating a chelating additive within a polymer hydrogel matrix to address these limitations. The chelating additive regulates the Zn²⁺ ion flux, suppressing the dendritic growth and facilitating uniform Zn plating/stripping, thereby enhancing the anode reversibility. Simultaneously, the polymer hydrogel electrolyte provides a mechanically robust framework with high ionic conductivity, mitigating Mn dissolution from the MnO₂-based cathode and suppressing the cathode–anode crosstalk, even at practical cathode loadings. The synergistic effects of the chelating agent and polymeric network significantly enhance the electrochemical performance, as evidenced by improved cycling stability, superior rate capability, and increased coulombic efficiency compared to conventional aqueous electrolytes. The computational insights from DFT identify strong Zn²⁺–polymer coordination and restricted Mn²⁺ dynamics, corroborating the experimentally observed stabilization. This study emphasizes the crucial role of electrolyte engineering in tailoring the performance of high-performance ARZMBs and offers a strategic approach for stabilizing the Zn metal interfaces through the design of functionalized electrolytes.