The electrochemical properties of SnC2O4-coated Si materials with various compositions were investigated. Among them, the Si-70 wt%SnC2O4 composite maintained a high capacity of greater than 1000 mAhg(-1) after more than 30 cycles. A synchrotron XRD analysis revealed that the SnC2O4 decomposed into Sn and an irreversible product during the first lithiation process. Subsequently, Sn and Si were independently lithiated/de-lithiated to Li17Sn4 and Li15Si4, respectively, during the Li insertion and de-insertion process. A full-cell using LiFePO4 as the positive electrode material was assembled, and the cell exhibited a good cycle performance in which it maintained almost 100% of the initial capacity after 100 cycles in the temperature range of -20-60 degrees C. The 1-Ah class cell showed a high safety during a nail penetration test and an overcharge test; no smoke and flames were observed during these safety tests. (C) 2013 The Electrochemical Society. All rights reserved.