Facile Preparation of MoS2 Nanocomposites for Efficient Potassium-Ion Batteries by Grinding-Promoted Intercalation Exfoliation.

Efficient exfoliations of bulk molybdenum disulfide (MoS2 ) into few-layered nanosheets in pure phase are highly attractive because of the promising applications of the resulted 2D materials in diversified optoelectronic devices. Here, a new exfoliation method is presented to prepare semiconductive 2D hexagonal phase (2H phase) MoS2 -cellulose nanocrystal (CNC) nanocomposites using grinding-promoted intercalation exfoliation (GPIE). This method with facile grinding of the bulk MoS2 and CNC powder followed by conventional liquid-phase exfoliation in water can not only efficiently exfoliate 2H-MoS2 nanosheets, but also produce the 2H-MoS2 /CNC 2D nanocomposites simultaneously. Interestingly, the intercalated CNC sandwiched in MoS2 nanosheets increases the interlayer spacing of 2H-MoS2 , providing perfect conditions to accommodate the large-sized ions. Therefore, these nanocomposites are good anode materials of potassium-ion batteries (KIBs), showing a high reversible capacity of 203 mAh g-1 at 200 mA g-1 after 300 cycles, a good reversible capacity of 114 mAh g-1 at 500 mA g-1 , and a low decay of 0.02% per cycle over 1500 cycles. With these impressive KIB performances, this efficient GPIE method will open up a new avenue to prepare pure-phase MoS2 and promising 2D nanocomposites for high-performance device applications.