Structural and Electrochemical Characterization of Pure LiFePO4 and Nanocomposite C-LiFePO4 Cathodes for Lithium Ion Rechargeable Batteries

Autor: Arun Kumar, R. Thomas, N. K. Karan, J. J. Saavedra-Arias, M. K. Singh, S. B. Majumder, M. S. Tomar, R. S. Katiyar
Jazyk: angličtina
Rok vydání: 2009
Předmět:
Zdroj: Journal of Nanotechnology, Vol 2009 (2009)
Druh dokumentu: article
ISSN: 1687-9503
1687-9511
DOI: 10.1155/2009/176517
Popis: Pure lithium iron phosphate (LiFePO4) and carbon-coated LiFePO4 (C-LiFePO4) cathode materials were synthesized for Li-ion batteries. Structural and electrochemical properties of these materials were compared. X-ray diffraction revealed orthorhombic olivine structure. Micro-Raman scattering analysis indicates amorphous carbon, and TEM micrographs show carbon coating on LiFePO4 particles. Ex situ Raman spectrum of C-LiFePO4 at various stages of charging and discharging showed reversibility upon electrochemical cycling. The cyclic voltammograms of LiFePO4 and C-LiFePO4 showed only a pair of peaks corresponding to the anodic and cathodic reactions. The first discharge capacities were 63, 43, and 13 mAh/g for C/5, C/3, and C/2, respectively for LiFePO4 where as in case of C-LiFePO4 that were 163, 144, 118, and 70 mAh/g for C/5, C/3, C/2, and 1C, respectively. The capacity retention of pure LiFePO4 was 69% after 25 cycles where as that of C-LiFePO4 was around 97% after 50 cycles. These results indicate that the capacity and the rate capability improved significantly upon carbon coating.
Databáze: Directory of Open Access Journals
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