Surface-Coated Silicon Anodes with Amorphous Carbon Film Prepared by Fullerene C60 Sputtering

Abstract

Surface-coated silicon films with an amorphous carbon film are prepared by radio-frequency magnetron sputtering using the fullerene C60 target. The carbon-coated silicon films are used as anode materials for lithium ion batteries and then investigated by the electrochemical measurements such as cyclic voltammetry and charge–discharge tests. Compared to the bare silicon anodes, the carbon-coated samples show more improvements in their electrochemical performances with a smaller irreversible capability in the first cycle and more stable cycle performance and maintain a high specific capacity of 2872 mAh g−1 until the 50th cycle under a current density of 100 A cm−2. It can be attributed to the presence of carbon film as an artificial passive layer to suppress the side reaction with the electrolyte. Additionally, the carbon layer can also provide a compressive stress, which may reduce the effect of a large volume change in silicon anodes during the charge–discharge tests, as indicated by the Raman spectroscopy recorded after the cycle tests.