High-Capacity, Microporous Cu6Sn5-Sn Anodes for Li-Ion Batteries

Three-dimensional, microporous Cu6Sn5-Sn architectures were created by electrodeposition of copper and tin onto sintered copper foam substrates and evaluated as anodes for lithium-ion batteries. The electrodes were characterized before and after cycling by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectrometry. Before cycling, the electrochemically deposited films consisted of a combination of crystalline Cu6Sn5 and Sn, whereas after cycling, the films appeared amorphous to X-rays. When evaluated in coin cells against metallic lithium, the composite Cu6Sn5-Sn electrodes delivered a reversible capacity of 670 mAh/g, which is significantly greater than the capacity achieved previously from powdered (ballmilled) and thin-film (sputtered) Cu6Sn5 electrodes, typically 200-350 mAh/g. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3094033] All rights reserved.