Preparation of LiFePO4/C nanocompostite and study of the effect of electrolyte on the electrochemical performance for Li-Ion rechargeable batteries

In this study, LiFePO4/carbon (LFP/C) nanocomposite was successfully prepared by hydrothermal method in which sucrose was used as carbon precursor. The obtained composite was characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The results showed that this nanocomposite possessed a high-crystallized LFP with a olevin structure and rod-type particles morphology with the size of 100-500 nm. The LFP/C cathode yields showed good capacity of 110 mAh g-1 at 0.1 C as well as high columbic efficiency of 95% in term of using 1.0 M LiPF6 in EC/DMC (1/1). In the case of using an additional 2% VC in the electrolyte system, the specific capacity was 136 mAh g-1 and columbic efficiency was nearly 100%. The superior electrochemical performances can be attributed to the formation of SEI layers on the electrode surface by VC decompostion, leading to suppressed the additional SEI formation from the other solvent, reduced charge-transferred resistance and improving cell capacity as well as long-term capacity retention.