Study on solution combustion synthesis and electrochemical performance of V₂O₅–Cu as cathode materials for aqueous zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) are widely regarded as a highly potential alternative power source, chiefly owing to the superior safety characteristics. Vanadium-based compounds, especially V₂O₅ cathode materials, have been widely studied due to the advantages of suitable working voltage windows and highly reversible redox reactions. Nevertheless, the inadequate conductivity of V₂O₅ and its intrinsic structural instability have hindered its utility in AZIBs. This study introduces a straightforward one-step solution combustion method for synthesizing copper-ion-doped V₂O₅, aimed at enhancing its structural robustness and electrochemical efficacy. The modified material resulted in expanded interlayer spacing, increased ionic diffusion rate, higher concentration of low-valence vanadium and oxygen vacancies, consequently enhancing electron mobility and facilitating electrochemical reactions. This enhancement led to an increased discharge specific capacity of the material. When V₂O₅–Cu is employed as the cathode material in aqueous zinc-ion batteries, it achieves a discharge specific capacity of up to 300 mAh g⁻¹ at a current density of 4 A g⁻¹. Moreover, after 500 cycles, the battery retains approximately 95% of its initial capacity.