Nanoprobe characterization of MoS2 nanosheets fabricated by Li-intercalation

We have fabricated MoS2 nanosheets by using a liquid-phase Li-intercalation method. To develop a process for the preparation of highly dispersed single-layer MoS2 nanosheets in water, we studied the mechanism of intercalation and exfoliation of MoS2. The water desorption behavior of the MoS2 nanosheets during heat treatment was investigated by in situ atomic force microscopy (AFM) and scanning transmission electron microscopy (STEM). By the analysis of each measurement, the amount of desorbed water existing in the interlayer and on the surface of MoS2 nanosheets could be estimated. Furthermore, we observed the water absorption behavior of Li-intercalated MoS2 by X-ray diffraction (XRD). From the results, we found that the layer distance was expanded to a thickness of more than two layers of water molecules intercalated by water absorption. These results are important to develop an effective approach to fabricate high-yield, single-layer MoS2 nanosheets dispersion based on a Li-intercalation method.