Li3V2(PO4)3 modified LiFePO4/C cathode materials with improved high-rate and low-temperature properties

LiFePO4/C surface modified with Li3V2(PO4)(3) is prepared with a sol-gel combustion method. The structure and electrochemical behavior of the material are studied using a wide range of techniques such as X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. It is found that LiFePO4/C surface modified with Li3V2(PO4)(3) has the better electrochemical performance. The discharge capacity of the as-prepared material can reach up to 153.1, 137.7, 113.6, and 93.3 mAh g(-1) at 1, 2, 5, and 10 C, respectively. The capacitance of the LiFePO4/C modified by Li3V2(PO4)(3) is higher under lower discharging rate at -20 A degrees C, and the initial discharge capacity of 0.2 C is 131.4 mAh g(-1). It is also demonstrated that the presence of Li3V2(PO4)(3) in the sample can reduce the charge transfer resistance in the range of -20 to 25 A degrees C, resulting in the enhanced electrochemical catalytic activity.