Gel-Polymer Electrolyte-Based High-Performance Zn-Ion Batteries with Vanadium-Oxide Cathode Material

Zn-ion batteries (ZIBs) are gaining attention due to their low cost, high capacity and efficiency, and strong cycling stability; nevertheless, further research is required to establish suitable cathode materials for the intercalation of Zn ions. Due to the layered structure, vanadium oxide–based materials are considered promising cathode materials of ZIB devices using gel polymer electrolytes (GPEs). The GPEs are considered a good alternative to liquid electrolytes due to their flexibility, leakage-free nature, and reduced Zn corrosion in Zn-based batteries. This work presents a carboxymethylcellulose and polyvinyl alcohol polymer matrix-based gel polymer electrolyte for applications in ZIBs for the first time. The polymer matrix shows an uptake of 150 wt% after immersion in 2 M ZnSO₄ electrolyte solution for 50 h. The as synthesized GPE has an ionic conductivity of 0.6 × 10⁻² cm⁻¹Ω⁻¹ and a thickness of 120 µm. The electrochemical results of the fabricated ZIB device fabricated using V₃O₇.H₂O cathode material exhibit a high specific capacity of 505 mAh/g at 0.1 A/g current density.