Enhanced electrochemical performance of LiFePO4/C wrapped with sulfur-modified reduced graphene oxide for Li-ion batteries
Although researchers have previously examined whether graphene modified by sulfur can improve the electrochemical performance of LiFePO 4 /C composites, they have rarely examined whether it can do so during the synchronous synthesis of LiFePO 4 /C and sulfur-modified reduced graphene oxide (SG) via...
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Published in | Ionics Vol. 28; no. 1; pp. 191 - 200 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
Berlin/Heidelberg
Springer Berlin Heidelberg
2022
Springer Nature B.V |
Subjects | |
Online Access | Get full text |
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Summary: | Although researchers have previously examined whether graphene modified by sulfur can improve the electrochemical performance of LiFePO
4
/C composites, they have rarely examined whether it can do so during the synchronous synthesis of LiFePO
4
/C and sulfur-modified reduced graphene oxide (SG) via a one-step hydrothermal method. To answer this question, a series of olivine structure LiFePO
4
/C composites wrapped with SG were investigated. Subsequently, we found that SG can form a three-dimensional conductive network on the surface of the LiFePO
4
/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 LiFePO
4
/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 Na
2
S 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 Ω, and the lithium-ion diffusion coefficient is 2.41 × 10
−14
cm
2
·S
−1
. The significance of these results is that they indicate that wrapping LiFePO
4
/C with SG significantly contributed to the improvement of its electrochemical performance. |
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ISSN: | 0947-7047 1862-0760 |
DOI: | 10.1007/s11581-021-04339-9 |