Effects of vanadium oxide coating on the performance of LiFePO4/C cathode for lithium-ion batteries

Abstract

LiFePO4 cathode material is considered as prospective materials for lithium-ion batteries and attracted great interest because of excellent cyclic performance and environmentally friendliness. However, LiFePO4 material suffers from inferior electronic and Li+ conductivity, which restricts its performance at high rate. Improving the interfacial stability and the interfacial charge transfer of the electrode is a necessary method to enhance the cycle and rate capability. Herein, vanadium oxide decoration on LiFePO4/C composites was obtained via a simple wet chemical method. The results show that a moderate amount of vanadium oxide hybrid stabilizes the structure of the matrix LiFePO4 material. Vanadium oxide and the residual carbon coating construct a mixed conductive network, which optimizes the interface structure and reaction dynamics of the electrode. In addition, the charge transfer resistance of the decorated hybrid is smaller and the Li+ diffusion ability is better than pristine LiFePO4/C material. Moreover, the electrochemical performance exhibits a promising high rate capability and perfect cycle ability, showing the discharge specific capacities of 157.2, 150.6, and 131.1 mAh g−1 at 0.1 C, 1 C, and 3 C respectively. Furthermore, the capacity retention reached 90.9% after the 1000th cycle at 3 C.