Preparation and electrochemical properties of Zr-doped LiV3O8 cathode materials for lithium-ion batteries

Abstract

The serial Zr-modified lithiated vanadium oxides LiV3 − xZrxO8 (x = 0.00, 0.02, 0.04, 0.06, and 0.08) as cathode materials were prepared using a sol–gel method. The synthesized cathode materials have been characterized by X-ray diffraction, scanning electron microscopy, galvanostatic charge–discharge test, cyclic voltammetry, and electrochemical impedance spectroscopy. The results indicate that doped Zr ion does not destroy the lattice structure of LiV3O8, while enlarging the (100) plane spacing. The discharge–charge tests show that LiV2.94Zr0.06O8 has the best electrochemical properties. The LiV2.94Zr0.06O8 electrode exhibits a high discharge capacity of 269.7 mAh g−1 at a charge–discharge rate of 0.1 C in the voltage range of 1.8–4.0 V and maintains a stable capacity of 246.9 mAh g−1 within 50 cycles. AC results indicate after Zr4+ doping, the charge–transfer resistance and the resistance of lithium-ion diffusion reduce greatly compared to the undoped LiV3O8, which is favorable to the lithium-ion fast intercalation/deintercalation in bulk materials.