Inorganic-based sol-gel synthesis of nano-structured LiFePO/C composite materials for lithium ion batteries.

An inorganic and non-toxic compounds combination of FeCl·4HO, LiCO and HPO was chosen to synthesize homogeneous nano-structured LiFePO/C composite material via a simplified sol-gel route. The dependency of the physicochemical properties and the corresponding electrochemical responses on the residual carbon content were investigated in details. Rietveld refinement of X-ray diffraction measurement and X-ray photoelectron spectroscopy analysis confirmed the feasibility of preparing pure LiFePO phase via this approach. With increasing amount of residual carbon, the particles size gradually decreased and the bulk electrical conductivity monotonically increased. However, the higher level of residual carbon would bring disadvantageous impact on the lithium ion diffusion. Due to high electrical conductivity, controlled particle size and suitable microstructure, the sample with 4.5 wt.% residual carbon exhibited stable cycling performance and delivered high discharge capacity of 163, 119 and 108 mA h g at 0.1 C, 5 C and 10 C, respectively. [ABSTRACT FROM AUTHOR]