Cobalt‐catalyzed tunable carbon microstructures from halogenated SiC preceramic precursors

Carbide-derived carbons (CDCs) with highly graphitized domains, linear, oval-shaped, and barrel-like structures have been prepared from a silicon carbide preceramic precursor containing catalytic amounts of cobalt. The chlorination temperature as well as the amount of catalysts will determine the specific surface area, pore size, and morphology of the obtained carbons. At low chlorination temperature, an amorphous network with significant amount of double or single oxygenated bonds was obtained. At 700 and 800 degrees C both linear graphitic domains and barrel-like carbon dominate the microstructure with an increased presence of microporosity. There barrel-like structures provided increased specific capacitance, although the high anisotropy of the structure compromises the energy density of the device. At 900 degrees C, despite the disappearance of this cropped surface, the hierarchical pore distribution and low O content also induce an increase of the specific capacitance of the CDC samples regardless of their high percentage of micropores.