Comparison of mechanically alloyed and sputtered tin-cobalt-carbon as an anode material for lithium-ion batteries

High energy ball milling, vertical-axis attritor milling and co-sputtering were used to prepare Sn30Co30C40 or Sn36Co41C23 electrode materials. By varying the milling conditions, it was possible to obtain nanostructured materials by mechanical methods whose X-ray diffraction patterns mimicked the diffraction pattern of the co-sputtered material. Electrochemical testing showed that composite electrodes made from each of the prepared materials showed stable charge-discharge capacity for at least 100 charge-discharge cycles and stable differential capacity versus potential profiles. Although the materials appear to be similarly nanostructured, the sputtered material showed a reversible capacity near 610 mA h/g, close to the theoretical capacity of 661 mA h/g, while the best material prepared by mechanical methods attained a specific capacity near 470 mA h/g. Further experiments are required to understand the differences in the nanostructure of these materials that leads to the differences in attained specific capacity. (C) 2007 Elsevier B.V. All rights reserved.