Electrochemical performance and spectroscopic characterization of native and TiO2-coated LiNi0.8Co0.2O2 were investigated. The electrochemical results showed TiO2-coated materials exhibited better cycle stability in the different potential regions (i.e. 3.0–4.3 and 3.0–4.6V) and the decomposition of the electrolytes was suppressed on coated materials surface. In addition, FT-IR and temperature-programmed desorption–mass spectroscopy (TPD–MS) results demonstrated that different oxidation products were formed on the native and coated electrodes. A possible decomposition mechanism of the electrolytes has been proposed based on our results.