Glass-ceramic LiFePO4 for lithium-ion rechargeable battery

Glass-ceramic LiFePO4 was synthesized through the crystallization of glass powder prepared by melting low-cost raw materials in ambient air. To obtain the homogeneous precursor glass, the addition of a small amount of Nb2O5 was effective. Ferric ions in the precursor glass were reduced and precipitated as LiFePO4 through the heat treatment of a mixture of the glass powder and a carbon source. The obtained glass-ceramic particles contained a LiFePO4 crystalline phase and a carbon-containing surface amorphous layer with a thickness of about 20 nm. A lithium-ion rechargeable battery fabricated with the glass-ceramic powder showed better high-rate performance than that of a battery made using commercial LiFePO4 ceramic powder. The better performance of the battery with the glass-ceramic is attributed to the existence of the surface amorphous layer. This synthesis process, consisting of glass melting in air and the subsequent crystallization of glass powder, has the potential to be used for the large-scale continuous production of high-performance LiFePO4. (C) 2011 Elsevier B.V. All rights reserved.