The effects of local graphitization on the charging mechanisms of microporous carbon supercapacitor electrodes

International audience; The electrochemical quartz crystal microbalance (EQCM) technique has been used to study the charge mechanisms in two TiC-derived nanoporous carbons (CDC), synthesized at 800 ℃ and 1100 ℃. These two carbons have a similar pore size and porous volume, but the CDC prepared at 1100 • C shows a more graphitic microstructure. The EQCM study revealed that the charge storage mechanism in the CDC-800 is mainly controlled by a counterion adsorption process, while an expanded ion-exchange process was observed for the CDC-1100. Combined with the potential of zero charge (PZC), these measurements suggest a strong interaction between the anions and graphitic carbon. For the first time, we provide experimental evidence that the local carbon structure affects the charge storage mechanism of the electrical double-layer capacitance in high surface area porous carbons.