▎ 摘　　要

Although researchers have previously examined whether graphene modified by sulfur can improve the electrochemical performance of LiFePO4/C composites, they have rarely examined whether it can do so during the synchronous synthesis of LiFePO4/C and sulfur-modified reduced graphene oxide (SG) via a one-step hydrothermal method. To answer this question, a series of olivine structure LiFePO4/C composites wrapped with SG were investigated. Subsequently, we found that SG can form a three-dimensional conductive network on the surface of the LiFePO4/C sample. In the process, XRD and HRTEM tests were undertaken as well. From the XRD test, the results show that SG does not affect the olivine structure of LiFePO4/C. In the HRTEM experiment, clear lattice fringes and a uniformly coated carbon layer on the sample surface were observed. Alongside these results, there were 4 others. First, the charge-discharge data showed that the electrochemical performance of the samples could be increased by SG modification. Second, sample S2 with a mass ratio of Na2S to rGO of 1:10 shows the best specific discharge capacity and stability. Third, the specific capacity of S2 is 163 mAhg(-1) at 0.2 C, and the capacity retention is 108.23% even after 200 cycles at a magnification of 10 C. Fourth, according to EIS, the charge migrating resistance of S2 is 226.4 omega, and the lithium-ion diffusion coefficient is 2.41 x 10(-14) cm(2)center dot S-1. The significance of these results is that they indicate that wrapping LiFePO4/C with SG significantly contributed to the improvement of its electrochemical performance.