Electrochemical Performance of Cathode LiVOPO₄ Doped with Mo and W

Abstract

Molybdenum (Mo) and tungsten (W) substituted LiV_0.99X_0.01OPO₄ (X = Mo and W) compounds were synthesized by impregnation method. The structures of samples were characterized by X-ray diffraction, and their electrochemical properties were studied by using charge-discharge in galavanostatic mode versus Li⁺/Li. The electrical conductivity of the samples was estimated by using impedance spectroscopy measurement with 2 point probe method at room temperature. Phosphates of composition LiV_0.99X_0.01OPO₄ with 1% Mo and W content in the structure exhibits high intercalation potential of 3.95 V versus Li/Li⁺. It was found that the electrical conductivity of Mo and W substituted samples at room temperature was improved to 4.8 × 10^–6 and 1.5 × 10^–5 S.cm^–1, respectively. Discharge capacity was also observed for the W doped sample with good retention performance up to 20 cycles at high current density of C/5 (0.4 mA.cm^–2).

Keywords:

• Lithium vanadyl phosphate
• Doping effects
• Electrical conductivity
• Cathode