Ti3SiC2 Modified LiFePO4/C Cathode Materials with Improved Electrochemical Performance

LiFePO4/C was modified with highly conductive nanolaminated Ti3SiC2 via a suspension mixing method followed by heat-treatment at 400 degrees C. The samples of pristine LiFePO4/C and Ti3SiC2-modified LiFePO4/C were characterized by X-ray diffraction (XRD), Raman spectroscopy, high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), galvanostatic charge/discharge test, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and potential step chronoamperometry (PSCA). It was found that a Ti3SiC2-based conducting network characterized by a "plane-to-point" conducting mode was constituted in the LiFePO4/C cathode. Electrochemical test results indicated that the addition of Ti3SiC2 not only improved the discharge capacity at high rates, but also enhanced the electrochemical reversibility. It also alleviated the charge transfer impedance and facilitated the diffusion of lithium ion. The 4 wt% Ti3SiC2-modified LiFePO4/C sample exhibited the best electrochemical performance. For example, the sample provided higher capacities of 140.4 and 101.2 mAh g(-1) than those of pristine sample (121.0 and 63.4 mAh g(-1)) at 1 C and 5 C, respectively. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.064212jes] All rights reserved.