Scalable synthesis of few-layered MoS2/C sandwiched nanocomposites via ionic crystal (NH4)2MoS4 assisted ball-milling method and their enhanced high-rate lithium storage property

Ball milling has been proven to be an efficient method for exfoliating and reassembling heterogeneous layered nanocomposites on a large scale. This study explores the use of ammonium tetrathiomolybdate (NH 4 ) 2 MoS 4 , an ion crystal with an octahedral structure, as both a precursor of layered molybdenum disulfide (MoS 2 ) and an intermediate during ball milling to assist in the exfoliation and fragilization of expandable graphite (EG). Due to its ion crystal structure and high hardness, (NH 4 ) 2 MoS 4 can efficiently transfer and magnify the impacting and shearing forces generated during the ball milling process, accelerating the exfoliation and fragmentation efficiency of EG. Moreover, (NH 4 ) 2 MoS 4 is nano-crystallized by the ball milling forces and uniformly distributed on the carbon nanosheets. Electrochemical performance tests indicate that the resulting nanocomposites, with a satisfactory heterogeneous structure, exhibit excellent Li-storage capacity, achieving 529 mA h g −1 after 150 cycles at a high current density of 500 mA g −1 . The relationship between the microstructure and improved electrochemical performance, as well as the formation mechanism of the product, is discussed in detail. This study provides a new approach for conveniently constructing nanocomposites using two types of layered materials that offer satisfactory rate capability and cyclability, making them potentially suitable for application in Li-ion batteries.