Abstract:Lithium iron phosphate is a new kind of cathode materials for lithium ion battery. It has found wide applications in lithium ion battery industry. It has excellent comprehensive electrochemical performance. Unfortunately, its high rate performance is not satisfactory. In order to enhance its conductivity and improve the high rate performance of the cathode material, highly conductive Ti3SiC2 modification was adopted. Ti3SiC2 modified LiFePO4/C powders were prepared via a ball milling process followed by heat-treatment at 400 °C. The effects of addition amount of Ti3SiC2 on electrochemical performance of the cathode material were investigated. It is found that a Ti3SiC2-based conducting network characterized by a “plane-to-point” conducting mode is constituted in the LiFePO4/C cathode. Galvanostatic charge/discharge test indicates that Ti3SiC2 modification is effective to improve the discharge capacity at high rates. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and potential step chronoamperometry (PSCA) measurements prove that the Ti3SiC2-based conducting network enhances electrochemical reversibility, alleviates charge transfer impedance and facilitates lithium ion diffusion (from 8.5′10?11 cm2·s?1 to 8.2′10?10 cm2·s?1). The 4wt% Ti3SiC2-modified LiFePO4 sample exhibits the best electrochemical performance with capacities of 131.7, 119.6 and 97.4 mAh·g?1 at 1 C, 2 C and 5 C, respectively, much higher than those without Ti3SiC2 modification. They are only 120.8, 101.9 and 64.0 mAh·g?1 at the corresponding rates, respectively