Abstract: Ni ²⁺ -doped V ₂ O ₅ cathode materials were synthesized by liquid deposition process with NiSO₄·6H₂O as dopant. The effects of Ni ²⁺ on the physical and chemical properties of the target compounds were investigated. The material structure, microphology and grain sizes were characterized by XRD and SEM. Galvanostatic method and AC impedance were used to measure the electrochemical performance of the material. The results show that the Ni ²⁺ doping affects the product structure slightly, and it is helpful to reduce the impedance of charge transfer in V₂O₅. With the increase of doping content, the capacitor specific energy increases. With the 2.5% Ni ²⁺ doping content, the highest specific energy of the capacitor is up to 15.6Wh·kg^-1 and coulomb efficiency is 95.12%.