Fabrication of macroporous carbon monoliths with controllable structure via supercritical CO2 foaming of polyacrylonitrile

In this paper, a supercritical CO2 (sc-CO2) foaming-based method is reported for fabricating controllable macroporous carbon monoliths with uniform cellular structures. In the proposed method, we obtain carbon monoliths through sequential steps of hot-pressing, sc-CO2 foaming, and carbonization. X-ray diffraction, Fourier-transform infrared, and Raman results demonstrate that the PAN foams transform into semi-graphitic carbons following carbonization, and the unchanged peak positions of different carbons indicate that changing foaming condition does not affect carbonization degree of the carbon monoliths. The carbon monolith fabricated from a foaming condition of 10.34 MPa and 100 degrees C exhibits an electrical conductivity of 132 S m(-1), which is greater than that of many typical porous carbon materials. Therefore, the proposed method provides a scalable and flexible strategy for fabricating macroporous carbon monoliths.