Highly Reversible Lithium Storage in Nanostructured Silicon

Anode materials of nanostructured silicon have been prepared by physical vapor deposition and characterized using electrochemical methods. The electrodes were prepared in thin-film form as nanocrystalline particles ~12 nm mean diameter! and as continuous amorphous thin films ~100 nm thick!. The nanocrystalline silicon exhibited specific capacities of around 1100 mAh/g with a 50% capacity retention after 50 cycles. The amorphous thin-film electrodes exhibited initial capacities of 3500 mAh/g with a stable capacity of 2000 mAh/g over 50 cycles. We suggest that the nanoscale dimensions of the silicon circumvents conventional mechanisms of mechanical deterioration, permitting good cycle life. © 2003 The Electrochemical Society. @DOI: 10.1149/1.1596917# All rights reserved.