Morphology regulation and vacancy engineering for vanadium oxide cathodes via tungsten doping towards advanced zinc-ion batteries

Abstract

Recently, vanadium oxide of V₆O₁₃ has emerged as a promising cathode material for aqueous zinc-ion batteries (AZIBs) due to its high theoretical specific capacity, abundant reserves, and the multiple adjustable oxidation states of vanadium. However, its poor electronic conductivity and severe structural collapse during cycling limit its practical application. Herein, a W⁶⁺-doped V₆O₁₃ nanobelt cathode was synthesized via a one-step solvothermal method. W⁶⁺ doping regulates the morphology of V₆O₁₃ from irregular nanosheets into nanobelts, increasing the specific surface area and improving the contact with electrolyte. Furthermore, W⁶⁺-doping induces more oxygen vacancies and activated more active sites, facilitating rapid diffusion of Zn²⁺. As a result, the WVO cathode delivers a high specific capacity of 472.6 mAh g⁻¹ at 0.5 A g⁻¹ and 266.4 mAh g⁻¹ at 10 A g⁻¹, with outstanding capacity retention of 82.4 % after 3,000 cycles at 10 A g⁻¹. This work provides valuable insights for the design of advanced aqueous zinc-ion cathodes.