Defect engineering and morphology adjustment assist NH4V4O10 to be a high-performance aqueous zinc ion battery cathode

Abstract

Vanadium-based materials hold significant promise as cathode materials for zinc-ion batteries owing to their high capacity and cost-effectiveness. However, their practical application is hindered by the sluggish diffusion kinetics of Zn²⁺ ions and the challenges of maintaining structural stability. Here, we report a high-performance ultrathin NH₄V₄O₁₀ nanosheet cathode (denoted as SNVO) rich in oxygen vacancies. Introducing oxygen vacancies improves the diffusion ability of Zn²⁺ ions, effectively accelerates the reaction kinetics, and enhances the material's stability. Furthermore, according to the DFT results, oxygen vacancies greatly enhance the material's conductivity. The ultrathin size of SNVO enables a larger specific surface area, providing more active sites for reversible deintercalation of Zn²⁺, thereby increasing the specific capacity. SNVO exhibits an impressive discharge capacity of 513 mA h g⁻¹ at 0.5 A g⁻¹, coupled with outstanding cycle stability, retaining 94.6% of its initial capacity even after 1000 cycles at 10 A g⁻¹.