We use density functional theory to investigate the interactions of Li+ and aliphatic carbonates such as ethylene carbonate and three linear carbonates (dimethyl, diethyl, and ethyl methyl), and the reductive decomposition mechanisms of these carbonates. On the basis of theoretical results and analyses, some phenomena relevant to the formation of a solid electrolyte interphase layer at the electrode surface of lithium ion batteries are well explained. This study also illustrates that theoretical analyses and calculations are able to provide useful insights into the design of components for modern power systems. (c) 2005 Wiley Periodicals, Inc.