Electrochemical Properties of Si-Co-Mn-Al-Modified Graphite Sphere Composites as Negative Electrode Materials for Li-Ion Batteries

ASi(1.81)-Co0.6Mn0.6Al0.3/modified graphite sphere composite (labeled as Si-1.81-Co0.6Mn0.6Al0.3/MGS) was prepared by high energy ball milling using nano-Si, Co, Mn, Al, and MGS as precursors. The compositions and morphology of the composite material were characterized by an X-ray diffractometer and scanning electron microscope. Constant current charge-discharge technique and electrochemical impedance spectroscopy were employed to investigate the electrochemical behaviors of Si-1.81-Co0.6Mn0.6Al0.3/MGS. Si-1.81-Co0.6Mn0.6Al0.3/MGS exhibits obviously improved cyclic performance with a high reversible capacity. The first reversible capacity of Si-1.81-Co0.6Mn0.6Al0.3/MGS is 574 mAh g(-1), and 91% of the capacity may be maintained after 70 cycles. The improvement of Si-1.81-Co0.6Mn0.6Al0.3/MGS in the electrochemical performance is attributed to the stability of the electrode structure upon cycling. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3392366] All rights reserved.