Electrochemical Behavior's of Diamond-Like-Carbon-Coated Silicon Monoxide-Graphite Composite Anode for Li-Ion Battery

The effects of a diamond-like carbon (DLC) coating on a silicon monoxide-graphite composite electrode are studied in order to improve the electrochemical characteristics of silicon monoxide anodes. The DLC is applied through plasma-enhanced chemical vapor deposition and identified by high-resolution transmission electron microscopy, Raman spectroscopy, and electron microprobe analysis. DLC-coated silicon monoxide- graphite composite anode/LiCoO2 full-cells (CR2032) are then assembled in an argon-filled glove-box. The discharge capacity of the coated cell is 523 mA h g(-1) at the first cycle and 409 mA h g(-1) at the 100th cycle at a 0.5 C rate. The 100-cycle capacity retention is 78.2%, which is greater than that of the bare cell (52%). The improved electrochemical characteristics of the DLC-coated cell are determined through impedance, energy-dispersive X-ray, and scanning electron microscopy analyzes. Because the DLC has a high Young's modulus and chemical stability, the coated silicon monoxide- graphite composite maintains a high capacity during cycling. (C) 2013 The Electrochemical Society.