Significantly Improved Electrochemical Performance in Li₃V₂(PO₄)₃/C Promoted by SiO₂ Coating for Lithium-Ion Batteries

Abstract

Li3V2(PO4)3/C (LVP/C) coated with various amounts of SiO2 has been synthesized, and the effect of surface modification by SiO2 on the performance of LVP has been systematically investigated with X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), magnetic susceptibility, Raman spectroscopy, and electrochemical measurements. Based on the analysis of XRD, XPS, and TEM, it is confirmed that SiO2 coating on the surface of LVP particles does not change the monoclinic structure of LVP. The XAS, XPS, and magnetic susceptibility results indicate that the valence of V in both the pristine and SiO2-coated LVP are close to +3. Furthermore, our results reveal that the electrochemical performance of LVP/C can be significantly improved by the SiO2 coating, which is due to the enhanced structural stability and reduced charge-transfer resistance.