Amorphous silicon (a-Si) films are deposited on LiFePO4@C electrode by using vacuum thermal evaporation deposition technique and the effect of alpha-Si film on electrochemical performance of LiFePO4@C cells is investigated systematically by the charge-discharge testing, cyclic voltammograms and AC impedance spectroscopy, respectively. The results reveal that the present of a-Si film on electrode surface could remarkably improve the electrochemical performance at high charge/discharge rate, especially at elevated temperature. This enhancement may be attributed to the amelioration of the electrochemical dynamics on the electrode/electrolyte interface resulting from the beneficial effects of a-Si film, which might significantly suppress the rise of both of the surface film resistance and charge transfer resistance.

Lithium-ion batteries; Cathode materials; Phosphor-olivine; Amorphous silicon

Fujian Normal University