Synergistically boosting the electrochemical performance of NH4V4O10/reduced graphene oxide/cellulose ternary composite for aqueous zinc ion batteries

Abstract

Ammonium vanadate (NH₄V₄O₁₀) serves as a potential cathode material for aqueous zinc-ion batteries (AZIBs) on account of its adjustable layered structure and significant specific capacity. Nevertheless, its sluggish intrinsic ion/electron kinetics and irreversible structural degradation during the cycling, result in less promising application potential. Herein, we present a swift synthesis method for the reduced graphene oxide (rGO)/cellulose nanofibers (CNFs)/NH₄V₄O₁₀ (denoted NCG-3) composite through a one-step hydrothermal process. By introducing rGO/CNFs, the interlayer spacing of NH₄V₄O₁₀ was significantly increased, and oxygen vacancies were introduced. The composite leverages the synergistic effects of rGO/CNFs for enhanced electrical conductivity and Zn²⁺ storage. Furthermore, density functional theory (DFT) calculations provide additional evidence that its charge transfer capability is enhanced. Consequently, NCG-3 demonstrates a significantly high capacity (344 mAh g⁻¹ at 1 A g⁻¹), approximately 3 times that of pure NH₄V₄O₁₀, alongside exceptional rate performance (291 mAh g⁻¹ at 5 A g⁻¹). The electrode is assembled into a flexible quasi-solid-state ZIB, which has almost without loss of capacity in various bending states, testifying its promising prospects for highlighting the potential of its wearable applications. This research proposes a rational strategy to design defective cathode materials to improve the electrochemical performance of AZIBs.