Improving the functionality of resorcinol-formaldehyde based carbon aerogels as electrode material for supercapacitor applications

Polymeric carbon and activated carbon aerogels were synthesized through sol-gel polycondensation reaction followed by the pyrolysis at 800 ºC under Argon (Ar) and physical activation under CO2 at different temperatures with different degrees of burn-off. The BET specific surface area (SSA) of the carbons was increased from 537 to 1775 m2g-1 and their total pore volume was increased from 0.24 to 0.94 cm3g-1 during the activation process while the pore size was kept constant around 2nm. Both non-activated and activated carbons were used as electroactive materials in an electrochemical capacitor. The capacitive behaviour of the electrodes was analysed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements using 6 M KOH as an electrolyte.
The results of CV measurements showed improved specific capacitance (SC) of 197 Fg-1 of activated carbon as compared to the SC of 136 Fg-1 when non-activated carbon was used as electrode material.
The result of EIS measurements showed low internal resistance indicating that the polymeric carbons possess a highly conductive three dimensional crosslinked structure. Due to their high specific surface area, controlled pore size, high conductivity and desirable capacitive behaviour these materials are preferred as electrode material for electrochemical capacitors.