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

Surface-coated silicon films with an amorphous carbon film are prepared by radio-frequency magnetron sputtering using the fullerene C-60 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 mu 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. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3363531] All rights reserved.