Simple, robust metal fluoride coating on layered Li123Ni0.13Co0.14Mn0.56O2 and its effects on enhanced electrochemical properties

Abstract

In present study, fluorine substituted Li1.23Ni0.13Co0.14Mn0.56O2-zFz (z=0-0.20) are synthesized by simple and low-temperature co-precipitation process and observed enhancement in their electrochemical properties are investigated as function of fluorine substitutions. F-19 MAS NMR analyses revealed the presence of fluorine as metal fluoride on the surface, and as oxy-fluoride in bulk Li(1.23)Ni(0.13)Co(0.14)Mn(0.56)O(2-z)Fz. Li1.23Ni0.13Co0.14Mn0.56O2-zFz (z=0.15) showed improved cycling performance and reduced cell impedance as a result of the fluorine doping. In addition, fluorine substitution controlled the amount of stabilizing transition metals in the lithium layers of spinel-like regions, which in turn resulted in countering the capacity loss and voltage decay compared to Li1.23Ni0.13Co0.14Mn0.56O2. (C) 2013 Elsevier Ltd. All rights reserved.