| LiFePO4/C was modified with highly conductive nanolaminated Ti3SiC2via asuspension mixing method and a ball mill mixing method, respectively. Themicrostructure and morphologies of these composites were characterized by XRD,Raman spectroscopy, HRTEM and SEM. The electrochemical performances wereevaluated by galvanostatic charge/discharge test, cyclic voltammetry, electrochemicalimpedance spectroscopy and potential step chronoamperometry.It was observed that a Ti3SiC2-based conducting network characterized by a“plane-to-point” conducting mode was constituted in the LiFePO4/C cathode, inwhich active LiFePO4/C particles were “bridged”. Electrochemical test resultsindicated that the addition of Ti3SiC2not only improved the discharge capacity at highrates, but also enhanced the electrochemical reversibility. It also alleviated the chargetransfer impedance and facilitated the diffusion of lithium ion.LiFePO4/C with x wt%Ti3SiC2（x=2,3,4,5） compositions were prepared via asuspension mixing method. The results of galvanostatic charge-discharge indicatedthat Ti3SiC2could improve the discharge capacity of LiFePO4/C, especially at thehigh rates. The4wt%Ti3SiC2-modified LiFePO4/C sample exhibited the bestelectrochemical performance. For example, the sample provided higher capacities of140.4and101.2mAh g-1than those of pristine sample （121.0and63.4mAh g-1） at1C and5C, respectively.The3-5wt%Ti3SiC2-modified LiFePO4/C samples were also prepared via a ballmill mixing method. It was found that the discharge capacities of Ti3SiC2-modifiedsamples were lower than those of the pristine LiFePO4/C at low current rates.However, it became higher than those of the pristine sample with the current rateincreased. The discharge capacities of4wt%Ti3SiC2-modified sample were132.4,119.9and98.7mAh g-1at1C,2C and5C, respectively. The electrochemicalperformances for the samples prepared via the ball mill mixing method were inferiorto those for the samples prepared via the suspension mixing method. |
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