Morphological investigation of sub-micron FePO{sub 4} and LiFePO{sub 4} particles for rechargeable lithium batteries
Microstructural variations of amorphous FePO{sub 4} and LiFePO{sub 4} (the latter obtained by chemical lithiation of the former) as a result of the annealing temperature have been studied by Thermogravimetric Analysis (TGA)/Differential Thermal Analysis (DTA), chemical analysis, Brunauer-Emmet-Taylor (BET) and Scanning Electron Microscopy (SEM) techniques. Round-shaped amorphous FePO{sub 4} particles 40-80 nm in size are obtained after heating (at 400 deg. C) amorphous FePO{sub 4}{center_dot}2H{sub 2}O in air (previously prepared by a precipitation route). On further heating at 650 deg. C, in air, crystalline trigonal FePO{sub 4} of crystallite size <200 nm is formed. Round-shaped amorphous LiFePO{sub 4} particles 40-80 nm in size crystallize by heating at 550 deg. C in Ar+5%H{sub 2} for 3 h. After thermal treatment, LiFePO{sub 4} particles are interconnected by necks, which resembled a sintering process. The particle size of LiFePO{sub 4} increases with an increase of temperature up to 750 deg. C, but an abnormal growth is evident at annealing temperatures above 650 deg. C. DTA analysis showed two exothermic peaks at 547 and 768 deg. C for FePO{sub 4} due to phase transitions, whereas for LiFePO{sub 4} two exothermic effects at 496 and 567 deg. C are shown.
- OSTI ID:
- 20887976
- Journal Information:
- Materials Research Bulletin, Vol. 38, Issue 7; Other Information: DOI: 10.1016/S0025-5408(03)00110-7; PII: S0025540803001107; Copyright (c) 2003 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0025-5408
- Country of Publication:
- United States
- Language:
- English
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