Bifunctional TiS2/CNT as efficient polysulfide barrier to improve the performance of lithium–sulfur battery

• Published in: Journal of alloys and compounds Vol. 832; p. 154947
• Main Authors: Pan, Siyi, Yin, Zhouhong, Cheng, Qi, Zhang, Guizhi, Yu, Xiaoyuan, Pan, Zhenxiao, Rao, Huashang, Zhong, Xinhua
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15-08-2020; Elsevier BV
• Subjects: Anchoring; Bifunctional interlayer; Carbon nanotubes; Charge transport; Functional materials; Lithium sulfur batteries; Modified separator; Performance enhancement; Polysulfide barrier; Polysulfides; Reaction kinetics; Separators; Sulfur; Titanium sulfide; Bifunctional interlayer; Titanium sulfide; Lithium-sulfur batteries; Polysulfide barrier; Modified separator
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2020.154947

Modifying the separator with functional materials is an effective strategy for building a polysulfide barrier to improve sulfur utilization in Lithium-sulfur (Li–S) batteries. Herein, flower-like TiS2 nanostructures consisting of ultrathin nanosheets are synthesized, and then coupled with highly conductive carbon nanotubes (CNTs) to construct TiS2/CNT modified separators, which provide sufficient active sites for anchoring polysulfides and offer a high-speed charge transport channel to accelerate the reaction kinetics. As a result, the TiS2/CNT cells display an initial specific capacity/reversible capacity of 1012/848 mAh g−1 after 100 cycles at 0.5 C and a specific capacity of 716 mAh g−1 at 3 C, which are significantly higher than those of the reference cells at corresponding current (729/471 mAh g−1 and 412 mAh g−1). Furthermore, the TiS2/CNT cells also provide a considerable capacity of 878 mAh g−1 under the sulfur areal-loading amount up to 10.5 mg cm−2, indicating the applicability of the TiS2/CNT modified separators in Li–S batteries. The results of cyclic voltammetry (CV) and electrochemical impedance spectra (EIS) have confirmed that TiS2/CNT modified separators can improve the mobility of Li ions and accelerate the reaction kinetics, reducing the internal resistance as well as the polarization voltage furthermore.
The bifunctional TiS2/CNT modified layer provides sufficient active sites and high-speed charge transport channel for acting an efficient polysulfide barrier to assist high-energy lithium-sulfur batteries. [Display omitted]
•Flower-like TiS2 was coupled with highly conductive carbon nanotubes.•This composite was modified on separator as an efficient polysulfide barrier.•This composite provides sufficient active sites and accelerate reaction kinetics.•The modified layer was employed to assemble high-energy lithium-sulfur batteries.