Affiliation:
1. School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative Molecules Shanghai Jiao Tong University 800 Dong Chuan Road Shanghai 200240 China
2. Guangzhou HKUST Fok Ying Tung Research Institute Nansha IT Park No. 2 Huan Shi Da Dao Road Nansha Guangzhou 511458 China
3. School of Electronic Information and Electrical Engineering Shanghai Jiao Tong University 800 Dong Chuan Road Shanghai 200240 China
Abstract
AbstractThe 2D materials exhibit numerous technological applications, but their scalable production is a core challenge. Herein, ball milling exfoliation in supercritical carbon dioxide (scCO2) and polystyrene (PS) is demonstrated to completely exfoliate hexagonal boron nitride nanosheets (BNNSs), graphene, molybdenum disulfide (MoS2), and tungsten disulfide (WS2). The exfoliation yield of 91%, 93%, 92%, and 92% and average aspect ratios of 743, 565, 564, and 502 for BNNSs, graphene, MoS2, and WS2, respectively, are achieved. Integrating exfoliated BNNSS in the polystyrene matrix, 3768 % thermal conductivity in the axial direction and 316% in the cross‐plane direction at 12 wt.% loading is increased. Also, the in‐plane and cross‐plane electrical conductivity of 6.3 × 10−4 S m−1 and 6.6 × 10−3 S m−1, respectively, and the electromagnetic interference (EMI) of 63.3 dB is achieved by exfoliated graphene nanosheets based composite. High thermal and electrical conductivities and EMI shielding are attributed to the high aspect ratio and ultrathin morphology of the exfoliated nanosheets, which exert high charge mobility and form better the percolation network in the composite films due to their high surface area. The process demonstrate herein can produce substantial quantities of diverse 2D nanosheets for widespread commercial utilization.