Liberating Free Coal Molecules by Exfoliation of Aggregated Coal.

Coal is a naturally occurring three-dimensional polymer, densely interlocked within a cross-linked matrix. Liberating free coal molecules from this aggregated solid form might unlock new pathways for the efficient and high-value utilization of coal resources. The critical challenge lies in rupturing the intermolecular forces within the coal network while preserving its macromolecular architecture intact. We propose a facile exfoliation strategy based on swelling and ultrasound, enabling the efficient transformation of coal from a solid aggregate into free molecules. The isolated coal molecules exhibit a rigid-flexible hybrid structure, which the flexible aliphatic chains protrude from the rigid aromatic scaffold. Notably, these exfoliated molecules demonstrate high electrical conductivity after annealing, which convert these coal molecules into two-dimensional, graphene-like sheets. This study offers fundamental insights into the molecular-level structure of coal and its exfoliation mechanism, paving the way for innovative applications in advanced materials and energy technologies.