Electrode Composite LiFePO4@Carbon: Structure and Electrochemical Performances

Abstract

This work aimed at preparing the electrode composite LiFePO4@carbon by hydrothermal and the calcination process was conducted at 600, 700, and 800°C. The structure and morphology were determined by X-ray diffraction (XRD), SEM, Raman spectroscopy, X-ray photon spectroscopy (XPS), and thermal analysis. The XRD refinement’s results point out the orthorhombic structure without impurity phase and the high crystalline of synthesized olivines. The results of Raman spectroscopy and XPS confirmed the pure olivine phase as well as the successful carbon coating on the surface of olivines’ powders. Moreover, the calcinated temperature affected the morphology as well as the electrochemical performance of synthesized olivines. The electrochemical measurements were conducted by cyclic voltammetry and galvanostatic cycling test. The diffusion coefficients were calculated from cyclic voltammetry curves and reached 1.09 × 10−12 cm2/s for LFP600, 2.28 × 10−11 cm2/s for LFP700, and 3.27 × 10−12 cm2/s LFP800. The cycling test at rate C/10 exhibited an excellent cyclability with discharge capacity of 145 mAh/g for LFP600, 170 mAh/g for LFP700, and 160 mAh/g for LFP800.