Supercritical mechano-exfoliation process
Hao Zhang, Qixuan Xiang, Zhiyuan Liu, Xianglong Zhang, Yaping Zhao, Huijun Tan
Abstract
The intricate balance among cost, output, and quality has substantially hindered the practical application of graphene within the downstream industry chain. Here we present a scalable and green supercritical CO2-assisted mechano-exfoliation (SCME) process that omits the use of organic solvents and oxidants throughout the production lifecycle, including exfoliation, separation, and purification. The SCME process achieves graphene powder space-time yields exceeding 40 kg/(m³·day) at laboratory (0.06–0.2 kg) and pilot scales ( > 4 kg), with resultant free-standing films showing conductivities up to 5.26 × 10⁵ S/m. Further kinetic investigations propose general guidelines for grinding-assisted exfoliation: (1) the macroscopic optimizing ability of mechanotechnics for mass transfer frequency and stress distribution and (2) the microscopic multiplication ability of exfoliation medium for shear-delamination. The comprehensive techno-economic analysis also underscores the economic viability of the SCME process for large-scale production. Here authors present a supercritical CO2-assisted mechano-exfoliation process that eliminates the need for organic solvents. Kinetic investigations offer general guidelines for optimising macroscopic mass transfer and microscopic shear-delamination in supercritical CO2 systems.