In-situ thermal activation of carbide-derived carbon Original Research Article

Microporous carbons attract high interest due to their application as a medium for gas storage, catalyst support or electrode material in lithium ion batteries or supercapacitors. Carbide-derived carbons (CDC) produced by halogenation of carbides exhibit a narrow pore size distribution and a tunable pore and microstructure by choosing the appropriate carbide precursor and chlorination temperature. However, the pore volume is limited by the amount of metal in the carbide structure, and the variation of pore size by varying the process conditions is not possible for all carbides. With an in-situ thermal activation in CO2 parallel to the chlorination, the porosity of the CDC materials can be further increased. This improved carbide-derived carbon process also allows producing novel pore structures which vary in the meso- to micropore ratio from the outside to the center of the particle. Thereby also the boarder case of shell-like carbon structures showing different pore size distributions in the shells can be produced. For this in-situ activation and chlorination of carbides the influence of the processing, the concentration of CO2 and activation time on the pore structure of CDC was studied.