Effect of aluminum fluoride coating on the electrochemical and thermal properties of 0.5Li(2)MnO(3)center dot 0.5LiNi(0.5)Co(0.2)Mn(0.3)O(2) composite material

Abstract

The positive effect of AlF3 (Al-F) coating on the over-lithiated transition metal oxide with a composition of 0.5Li(2)MnO(3)center dot 0.5LiNi(0.5)Co(0.2)Mn(0.3)O(2) has been investigated to address its potential use in lithium ion batteries. On the basis of various structural and electrochemical characterizations, we elucidate a correlation between surface structure and its electrochemical performance. After the controlled coating with AlF3 (Al-F), we observed notable improvements on cyclic performance and rate capability as well as thermal stability. We found that uniformly introduced AlF3 (Al-F) not only preserves the electrochemical kinetics at the surface of the oxide but also stabilizes its surface as a protective layer against electrolyte oxidation during the high voltage charging. Such improvements will provide a further progress on the development of high-capacity cathode materials fulfilled with the stringent safety requirements. (C) 2011 Elsevier B. V. All rights reserved.