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

Abstract Efficient exfoliations of bulk molybdenum disulfide (MoS 2 ) 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 (2 H phase) MoS 2 –cellulose nanocrystal (CNC) nanocomposites using grinding‐promoted intercalation exfoliation (GPIE). This method with facile grinding of the bulk MoS 2 and CNC powder followed by conventional liquid‐phase exfoliation in water can not only efficiently exfoliate 2 H ‐MoS 2 nanosheets, but also produce the 2 H ‐MoS 2 /CNC 2D nanocomposites simultaneously. Interestingly, the intercalated CNC sandwiched in MoS 2 nanosheets increases the interlayer spacing of 2 H ‐MoS 2 , 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 MoS 2 and promising 2D nanocomposites for high‐performance device applications.