Sol-gel synthesis of Li2CoPO4F/C nanocomposite as a high power cathode material for lithium ion batteries
- 化学化工－已发表论文 
Li2CoPO4F cathode materials are successfully synthesized by solid state (SS) and sol-gel (SG) methods. The XRD results show that Li2CoPO4F samples prepared by two methods are both indexed as orthorhombic structure with space group Pnma. The particles of Li2CoPO4F (SS) are micron grade. However, the particle of Li2CoPO4F (SG) is only tens of nanometers with an amorphous carbon uniformly coated. A high reversible capacity of 138 mAh g(-1) is achieved for Li2CoPO4F/C (SG) at 1 C, which is much higher than that of 106 mAh g(-1) prepared by solid state method. Also, Li2CoPO4FIC (SG) shows excellent rate performance, a capacity of 119 mAh g(-1), 86% retention of that at 1 C, is achieved at 20 C. The excellent rate capacity of the material is attributed to nanosized particles and uniform carbon coating that reduce ion diffusion length and enhance electronic conductivity. Furthermore, the preliminary performance characteristics of Li2CoPO4F/Li4Ti5O12 full cells are presented. The cell shows a high voltage plateau around 3.4 V with excellent rate capacity. The impressive electrochemical properties indicate that Li2CoPO4F can be a promising high power cathode material for lithium ion batteries. The capacity fading mechanism of Li2CoPO4F is also briefly investigated. (C) 2012 Elsevier B.V. All rights reserved.
CitationJOURNAL OF POWER SOURCES，2012（220）:122-129
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