Preparation and electrochemical properties of Y-doped Li3V2(PO4)3 cathode materials for lithium batteries

Y-doped Li3V2(PO4)(3) cathode materials were prepared by a carbothermal reduction(CTR) process. The properties of the Y-doped Li3V2(PO4)(3) were investigated by X-ray diffraction (XRD) and electrochemical measurements. XRD studies showed that the Y-doped Li3V2(PO4)(3) had the same monoclinic structure as the undoped Li3V2(PO4)(3). The Y-doped Li3V2(PO4)(3) samples were investigated on the Li extraction/insertion performances through charge/discharge, cyclic voltammogram (CV), and electrochemical impedance spectra (EIS). The optimal doping content of Y was x=0.03 in Li3V2-xYx(PO4)(3) system. The Y-doped Li3V2(PO4)(3) samples showed a better cyclic ability. The electrode reaction reversibility was enhanced, and the charge transfer resistance was decreased through the Y-doping. The improved electrochemical performances of the Y-doped Li3V2(PO4)(3) cathode materials were attributed to the addition of Y3+ ion by stabilizing the monoclinic structure.