Influence of TiO2 surface coating on the electrochemical properties of V2O5 micro-particles as a cathode material for lithium ion batteries

Abstract

V₂O₅ micro-particles were obtained by the mechanical milling process combined with a simple sintering treatment using commercial V₂O₅ powder as a raw material. We successfully adopted the hydroxylation of tetrabutyl titanate (C₁₆H₃₆O₄Ti) in air and a post-sintering procedure to synthesize the TiO₂-coated V₂O₅ micro-particles. Afterwards, systematic electrochemical characterization was performed to evaluate the electrochemical performance of V₂O₅ micro-particles as a cathode material for lithium ion batteries (LIBs) with and without the TiO₂ coating. As for the V₂O₅ micro-particles, the maximum discharge specific capacity reaches 247.8 mA h g⁻¹, which gradually decreases to 212.6 mA h g⁻¹ after 50 cycles at a current density of 100 mA g⁻¹ between 2 and 4 V (vs. Li/Li⁺). Under the same conditions, TiO₂ coated V₂O₅ micro-particles deliver the highest capacity of 246.6 mA h g⁻¹ and keeps at 229.1 mA h g⁻¹ for the 50^th cycle. The results indicated that the TiO₂ coating could effectively suppress the electrochemical property degradation of V₂O₅ crystalline micro-particles, improving its cycling stability during long-term charge–discharge measurements through the protective role of the TiO₂ layer.