Si/carbon nanocomposites with different Si distribution were prepared to the anode of Li-ion batteries for better cyclic properties. Si particles were milled by a high-energy multi-ring-type mill to decrease the crystallite size to 15 nm. Nanocomposite particles with controlled inhomogeneous spatial Si distribution were obtained by co-grinding with Cu powder. Heterogeneity of the Si distribution exhibited better cyclability than those with homogeneous Si distribution prepared from well-dispersed Si nanoparticles. We attribute the better cyclability to two factors, reduction of mechanical stress developed by electrochemical volume change of Si and networking of Si particles for maintaining conductive paths in the electrode. (c) 2005 The Electrochemical Society. [DOI: 10.1149/1.1856990] All rights reserved.