Suppression of cobalt dissolution from the LiCoO2 cathodes with various metal-oxide coatings

ZrO2-coated LiCoO2 showed negligible capacity loss up to 70 cycles at the cutoff voltage of 4.4 V, while bare LiCoO2 exhibited; 60% of its original capacity after only 30 cycles. The improved electrochemical behavior was caused by the suppression of cobalt dissolution by nanoscale metal-oxide coating. The amount of cobalt dissolution in the electrolyte from the charged LiCoO2 held at 25 and 90 degreesC, respectively, correlates well with the capacity retention, among coatings of various metal oxides. The trend of the open-circuit voltage reduction is again well correlated with both the cobalt dissolution and capacity retention. (C) 2003 The Electrochemical Society.