Two-birds with one stone: Improving both cathode and anode electrochemical performances via two-dimensional Te-CoTe2/rGO ultrathin nanosheets as sulfur hosts in lithium-sulfur batteries

• Published in: Journal of colloid and interface science Vol. 649; pp. 86 - 96
• Main Authors: Cheng, Zihao, Wang, Meili, Dong, Yutao, Han, Yumiao, Yan, Xueli, Xie, Lixia, Zheng, Xin, Han, Lifeng, Zhang, Jianmin
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.11.2023
• Subjects: Li2TexSy; Lithium-sulfur battery; Multiple effects; Sulfur host; Te-CoTe2/rGO; Multiple effects; Te-CoTe2/rGO; Li2TexSy; Lithium-sulfur battery; Sulfur host
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2023.06.037

The Te-CoTe2/rGO substrate not only has the strong adsorbing effect on lithium polysulfides (LiPSs), but also can accelerate the transformation of sulfur species during the charging/discharging process. At another hand, the intermediate Li2TexSy, which would be generated on the cathode surface via Te reacting with Li2Sn, might migrate to the anode to make the lithium deposition more uniform and inhibit the growth of lithium dendrites. This research not only shows that the two-dimensional ultrathin Te-CoTe2/rGO composite is successfully developed with multiple effects on Li-S batteries, but also open the new road for designing unique sulfur hosts to advance the electrochemical behavior of Li-S cells. [Display omitted] •The Te-dopped CoTe2 in-situ grows on rGO to form Te-CoTe2/rGO nanocomposites with an ultrathin layered structure.•The Te-CoTe2/rGO nanosheets as sulfur hosts would take the multiple positive effects on both sulfur cathode and lithium anode.•The in-situ XRD and in-situ Raman were tested to study on the sulfur conversion process. A Te-doped CoTe2 film could be grown in situ on reduced graphene oxide (rGO) to develop a Te-CoTe2/rGO composite with an ultrathin layered structure, which has multiple protective effects on both the sulfur positive electrode and lithium negative electrode in lithium sulfur (Li-S) batteries. The Te-CoTe2/rGO composite as a sulfur host not only shows a strong adsorbing ability for lithium polysulfides (LiPSs) but can also accelerate the conversion reaction of active material sulfur during the charging/discharging process. More importantly, this host can turn the shuttle effect from an unfavorable factor to a favorable factor, which could improve the electrochemical performance of the lithium anode with uniform lithium plating/stripping resulting from the intermediate polytellurosulfide species (Li2TexSy), which could be generated on the cathode surface via Te reacting with soluble Li2Sn (4 ≤ n ≤ 8). As a result, the S@Te-CoTe2/rGO cathode shows a discharge capacity of 970.0 mA h g−1 in the first cycle at 1 C and retains a high capacity of 545.5 mA h g−1 after 1000 cycles, corresponding to a low capacity decay rate of only 0.043% per cycle. In addition, in situ X-ray diffraction (XRD) and in situ Raman were used to explore the sulfur conversion process. This study not only demonstrates that a two-dimensional (2D) ultrathin Te-CoTe2/rGO composite is successfully developed with multiple effects on Li-S batteries but also opens a new pathway for designing unique sulfur hosts to promote the electrochemical performance of Li-S batteries.