Unveiling the relationship between the multilayer structure of metallic MoS 2 and the cycling performance for lithium ion batteries.

Molybdenum disulfide (MoS 2 ) with a layered structure is a desirable substitute for the graphite anode in lithium ion storage. Compared with the semiconducting phase (2H-MoS 2 ), the metallic polymorph (1T-MoS 2 ) usually shows much better cycling stability. Nevertheless, the origin of this remarkable cycling stability is still ambiguous, hindering further development of MoS 2 -based anodes. Herein, we assembled multilayered 1T-MoS 2 nanosheets directly on Ti foil to investigate the Li + storage mechanism. Based on experimental observation and computational simulation, we found that the cycling stability correlates with the layer number of MoS 2 . Multilayered 1T-MoS 2 can accommodate inserted Li + in a ternary compound Li-Mo-S through a reversible reaction, which is favorable for retaining a substantial number of MoS 2 nanodomains upon Li intercalation. These residual MoS 2 nanodomains can serve as an anchor to adhere Li x S species, thereby suppressing the "shuttle effect" of polysulfides and enhancing cycling stability. This work sheds light on the development of high-performance anodes based on metallic MoS 2 for LIBs.