Insights into the structural and surface characteristics of microporous carbide derived carbons obtained through single and double halogen etching

Carbide derived carbons CDC are prepared from polymeric preceramic precursors by incorporating different amounts of a divinylbenzene and heat treated at different temperatures. The effects of a single (Cl₂) and double (HF + Cl₂) etching treatment have been studied. The amount of divinlylbenzene incorporated into the preceramic precursor will determine the relative amount of linear to highly crosslinked silica units therefore the sensitivity to the etching process. The obtained microporous materials possess a self-similar surface and different microstructure depending on the temperature and the etching treatment which inevitably affect the electrochemical characteristics. Wet etching reduced the amount of zigzag edges in the microporous carbon thus contributing to the decrease of the areal capacitance. In the case of a single etching, the capacitance increases with the relative number of armchair to armchair + zigzag edges only when the materials were treated at high temperature. On contrary, by double etching treatment, the electrochemical characteristics are strongly related to the pore anisotropy independently on the temperature of the treatment. In this study we provide several clues for the design of highly capacitive microporous carbons from preceramic polymers with a view in the pore architecture, surface characteristics, defects, disorder and reactivity of the carbon edges.