1T-MoS2/carbon nanofiber composite as an interlayer fabricated by an in situ electrochemical fabrication method for lithium-sulfur batteries

Highlights: • The MoS₂/CNF as an interlayer was synthesized for Li-S batteries. • The in situ phase transition of 2H-MoS₂ to 1T-MoS₂ was electrochemically induced. • The 1T-MoS₂/CNF interlayer was found to effectively suppress the shuttle effect. • The interlayer acted as an upper current collector and a reservoir for Li-polysulfides. -- Abstract: Lithium-sulfur (Li-S) batteries are electrochemical energy devices that can store electrical energy in solid-state sulfur as a cathode. However, despite their high capacity and energy density, there are key issues for commercialization of Li-S batteries that need to be solved, such as shuttle effect to be solved. In this study, for high-rate performance Li-S batteries, we fabricated an interlayer consisting of molybdenum disulfide (MoS₂) and carbon nanofiber (CNF) (MoS₂/CNF). The in situ phase transition of 2H-MoS₂ to 1T-MoS₂ in the MoS₂/CNF was electrochemically induced. The 1T-MoS₂/CNF interlayer structure was found to effectively suppress the shuttle effect. The superior rate performance of the Li-S cell with 1T-MoS₂/CNF was found to result from the interlayer structures acting as an upper current collector and a reservoir for Li-polysulfides.