Synthesis and characterization of LiFePO₄/3-dimensional carbon nanostructure composites as possible cathode materials for Li-ion batteries

摘要

Composites of three-dimensional (3D) carbon nanostructures coated with olivine-structured lithium iron phosphates (LiFePO₄) as cathode materials for lithium ion batteries have been prepared through a Pechini-assisted reversed polyol process for the first time. The coating has been successfully performed on nonfunctionalized commercially available 3D carbon used as catalysts. Thermal analysis revealed no phase transitions till crystallization occurred at 579 °C. Morphological investigation of the prepared composites showed a very good quality of the coating on the 3D carbon structures. A great enhancement of the crystallinity of the olivine structure and of the composites was revealed by the structural investigation performed on pure LiFePO₄ and composites after annealing at 600 °C for 10 h under nitrogen atmosphere. The cyclic voltammetry curves of the composites show well-defined peaks and smaller value of the polarization overpotential indicating an enhancement of electrode reaction reversibility compared to the LiFePO₄ phase.