Highly Reversible Lithium Storage in Nanostructured Silicon

Abstract

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.