Synthesis of Li3Ni x V2-x (PO4)3/C cathode materials and their electrochemical performance for lithium ion batteries

Li3Ni (x) V2-x (PO4)(3)/C (x = 0, 0.02, 0.04 and 0.06) samples have been synthesized via an improved sol-gel method. X-ray diffraction patterns indicate that the structure of the prepared samples retains monoclinic, and the single phase has not been changed with Ni doping. From the analysis of electrochemical performance, the Li3Ni0.04 V-1.96(PO4)(3)/C sample exhibits the best electrochemical property. It delivers a discharge capacity of 112.1 mAh g(-1) with capacity retention of 95.2 % over 300 cycles at 10 C rate in the range of 3.0-4.8 V; cyclic voltammetry and electrochemical impedance spectra testing further prove that the electrochemical reversibility and lithium ion diffusion behavior of Li3V2(PO4)(3) have also been effectively improved through Ni doping.