Bilayered V2O5 nanostrands with a PVA-based cathode slurry for high-performance and sustainable zinc-ion batteries

Abstract

The increasing demand for sustainable and cost-effective batteries has accelerated in-depth research on zinc-ion batteries (ZIBs) as an ideal alternative to lithium-ion batteries (LIBs). V₂O₅ is a widely investigated material for charge storage due to its rich electrochemistry; however, the bulky crystalline structure of commercial V₂O₅ hinders its high potential by constraining Zn²⁺ ion migration, causing structural instability and resulting in premature failure. In this study, we present a low-cost, scalable and eco-friendly strategy to synthesize layered V₂O₅ via a one-pot process using polyvinyl alcohol (PVA) as a binder, producing a ready-to-coat cathode slurry. Furthermore, we eliminated the use of non-biodegradable and toxic fluorinated plastics, such as polyvinylidene fluoride (PVDF), and solvents, like N-methyl pyrrolidone (NMP), which are traditionally employed for cathode slurry preparation. The material prepared using the proposed method showed an interlayer spacing of 8.4 Å, which significantly improved Zn²⁺ ion migration. Furthermore, PVA-assisted binding improved the electrolyte–active material interphase, resulting in efficient charge transfer. Electrochemical characterization showcased the remarkable cyclability of the proposed cathode material, achieving a capacity of 480 mAh g⁻¹ at 0.5 A g⁻¹ for 100 cycles and an exceptional long-term cyclability of 280 mAh g⁻¹ at 4 A g⁻¹ over 6500 cycles, retaining 98% capacity in the last 6000 cycles. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic intermittent titration technique (GITT) further confirmed highly efficient and favourable charge-transfer kinetics with promising fast charging properties. This study highlights the potential of bilayered V₂O₅ nanostrands and green processing approaches for scalable and sustainable ZIB production, paving the way for next-generation grid-scale energy storage.