2D-2D heterostructure of ionic liquid-exfoliated MoS2/MXene as lithium polysulfide barrier for Li-S batteries

• Published in: Journal of colloid and interface science 2023-04, Vol.636, p.528-536
• Main Authors: Xie, Fangwei, Xu, Chunjie, Song, Yaochen, Liang, Qi, Ji, Jinjie, Wang, Sizhe
• Format: Article
• Language: English
• Subjects: adsorption; anodes; batteries; commercialization; energy; Interlayer; Ionic liquid; liquids; lithium; Lithium-sulfur batteries; MoS2; MXene; X-ray photoelectron spectroscopy
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2023.01.031

[Display omitted] •2D-2D heterostructure are designed by ionic liquid-exfoliated MoS2 and HF-exfoliated MXene.•The IL-MoS2/MX heterostructure is constructured to deliver sufficient Li+ and anchor towards LiPSs.•The IL-MoS2/MX cells achieve superior long-term cycling performance. Suppressing the dissolution and shuttling of lithium polysulfides (LiPSs) in electrolytes in lithium-sulfur batteries (LSBs) is the focus of researchers. Herein, functional liquid phase exfoliated MoS2 and MXene (IL-MoS2/MX) interlayer is proposed as the separator of LSBs. The unique alternating intercalation structure of the IL-MoS2/MX interlayer provides a channel for ion transport while achieving uniform Li+ deposition on the anode side. Moreover, IL-MoS2 achieves physical and chemical anchoring to LiPSs and lowers the energy barrier for battery reactions. As a result, the separator in the coin cell delivers an initial capacity of 764.4 mAh·g−1 at 1C and high retention of 58.7 % after 700 cycles, with a decay only 0.059 % per cycle. Simultaneously, the excellent stability is also verified under varying current densities. Beyond that, ionic conductivity and lithium-ion migration number are adopted to confirm unique ion transport channels and uniform deposition of lithium. X-ray photoelectron spectroscopy, S8 and Li2S decomposition and nucleation energy barrier analysis are performed to verify the adsorption and catalytic conversion mechanisms. The convenient preparation and excellent performance of IL-MoS2/MX provide a design strategy for functionalized interlayers for LSBs, and the possibility for commercialization.