AlF3-coated LiCoO2 and Li[Ni1/3Co1/3Mn1/3]O-2 blend composite cathode for lithium ion batteries

Abstract

Surface modifications of electrode materials can improve the electrochemical and thermal properties of cathodes for use in lithium batteries. In this study, AlF3-coated LiCoO2 and AlF3-coated Li[Ni1/3Co1/3Mn1/3]O-2 cathode materials are blended, as both have the same crystal structure and exhibit similar electrochemical properties. The composite electrodes exhibit high discharge capacities of 180-188 mAhg(-1) in a voltage range of 3.0-4.5 V at room temperature. The capacity retention of the composite electrode is greater than 95% of the initial capacity after 50 cycles. The thermal stability of these composite electrodes is greatly improved because of the superior thermal stability of AlF3-coated Li[Ni1/3Co1/3Mn1/3]O-2. The blended AlF3-coated LiCoO2 and AlF3-coated Li[Ni1/3Co1/3Mn1/3]O-2 electrode shows two exothermic peaks, one at 227 degrees C from AlF3-coated LiCoO2 and another at 277 degrees C from AlF3-coated Li[Ni1/3Co1/3Mn1/3]O-2. accompanied by significantly reduced exothermic heat generation. (C) 2010 Elsevier B.V. All rights reserved.