Effect of boron doped fullerene C60 film coating on the electrochemical characteristics of silicon thin film anodes for lithium secondary batteries

In this work, boron doped fullerene (B:C60) films were prepared by the radio frequency plasma assisted thermal evaporation technique for use as a coating material for the silicon thin film anode in lithium secondary batteries. Raman and XPS analyses revealed that the boron atoms were well inserted into the fullerene film lattices. The effect of the B:C60 film on the electrochemical characteristics of the silicon thin film was studied by charge–discharge tests, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The B:C60 coated silicon film exhibited a high reversible capacity of more than 1200 mAh g−1 when cycled 50 times between 0 and 2 V at a current density of 1200 μA cm−2 (1.5 C). The film also showed good rate capacity at different current densities and a more improved coulombic efficiency of 87.7% in the first cycle in comparison with that of the C60 coated film electrode.