Effect of La Doping on the Structure and Lithium Storage Performance of V2O5

La-doped vanadium pentoxide (V2O5) was prepared by sol-gel method and subsequent heat treatment in air at 400 degrees C. The influence of La-doping on the crystalline structure, surface morphology, and lithium storage performance of V2O5 were investigated by XRD, SEM, CV, EIS, and dischargecharge tests. The results demonstrated that La doping did not change the phase structure of orthorhombic V2O5, but significantly refined the crystal grain of V2O5; La doping obviously improved the cycling stability and rate capability of V2O5 due to the decreased electrode polarization, smaller electron-transfer resistance, and enhanced lithium diffusivity. For example, the La-doped V2O5 delivered a reversible capacity of 131 mAh/g after 50 cycles at a current density of 200 mA/g, while the pure V2O5 showed a reversible capacity of only 63 mAh/g under the same condition. At the high rate of 500 mA/g, the La-doped V2O5 still displayed a reversible capacity of 106 mAh/g, which is two times higher than that (45 mAh/g) of pure V2O5 sample.