Improving the performances of LiCoO2 cathode materials by soaking nano-alumina in commercial electrolyte

The electrochemical and thermal performances of commercial LiCoO2 as cathode material of lithium-ion batteries were improved by soaking the nano-Al2O3 in commercial LiPF6/ ethylene carbonate/ dimethyl carbonate electrolyte. The acidity of the new electrolyte is much higher than that of the original ( commercial ) electrolyte. These observations cannot be explained with traditional models of performance improvement by surface coating/ modification. A solid superacid model was proposed based on extended and comprehensive analyses. This model disagrees with previous improvement mechanisms and predicts that some other nanocompounds can also be used as additives for improving the performances of LiCoO2 cathode materials. (c) 2006 The Electrochemical Society.