Si-Ni-Carbon composite synthesized using high energy mechanical milling for use as an anode in lithium ion batteries

Abstract

Si-Ni-Carbon composite was prepared by two-step high energy mechanical milling process. The microstructure was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectrometry (EDS). The electrochemical properties have been investigated until the 50th cycle. As a result, Carbon was coated on the surface of the Si-Ni composite, where Ni was distributed in Si matrix and the Si-Ni-Carbon composite demonstrated a large reversible capacity of ca. 960 with an excellent cycling stability. The reasons for good electrochemical characteristics were analyzed by high resolution transmission electron microscope (HR-TEM), powder resistance analysis and Barret-Joiner-Halendar (BJH) analysis. Uniformly dispersed Ni improved electronic conductivity and induced fast charge transport significantly in the Si-Ni-Carbon composite. In addition, pores and disordered Carbon layer played a role of media to accommodate a large volume change of Si during cycling. Our experiments suggest that the Si-Ni-Carbon composite should be a promising new anode material for lithium ion secondary batteries with a high capacity. (c) 2006 Elsevier B.V. All rights reserved.