Polymer-Functionalized Cathode for Enhanced Long-Term Cycling Performance in Aqueous Zinc-Ion Batteries

Abstract

Aqueous zinc-ion batteries (AZIBs) have garnered significant attention due to their high safety, environmental friendliness, and remarkable cost-effectiveness. However, developing cathode materials with strong structural stability and long cycle life remains a critical challenge. Herein, chitosan-doped HNaV6O16·4H2O (HNVC) is synthesized via a hydrothermal process with chitosan incorporation to optimize the material’s nanostructure. Unlike conventional polymer doping, chitosan introduction exhibits behavior analogous to metal-ion intercalation, effectively stabilizing the layered framework. As a result, HNVC delivers remarkable cycling durability and maintains a capacity retention rate of 95.5% after 8500 cycles at 5 A g−1. Comprehensive electrochemical and spectroscopic analyses reveal that chitosan-assisted regulation reduces the interlayer spacing and enables a synergistic Zn2+/H+ co-intercalation mechanism, contributing to both enhanced capacity and structural robustness. This work provides a strategy for polymer-assisted structural engineering of vanadate-based cathodes toward high-performance AZIBs.