A study of the anodic oxidation of vinyl ethylene carbonate (VEC) was conducted with post-mortem analysis of reaction products by attenuated total reflection Fourier transform infrared analysis and gel permeation chromatography (GPC). The half-wave potential (E1/2) for oxidation of VEC is ca. 3.6 V, producing a resistive film on the electrode surface. GPC analysis of the film on a gold electrode produced by anodization of a commercial Li-ion battery electrolyte containing 2% VEC at 4.1 V showed the presence of high molecular weight polymers. IR analysis indicated polycarbonates with alkyl carbonate rings linked by aliphatic methylene and methyl branches. (c) 2005 The Electrochemical Society.