Gelatin-based activated carbon with carbon nanotubes as framework for electric double-layer capacitors

Gelatin-based activated carbons (GBACs) were prepared by activation of novel synthetic gelatin/carbon nanotubes (CNTs) hybrid foams for 2 h at 800 °C using KOH and 1:2 component ratio. The results of scanning electron microscopy (SEM) showed that CNTs were homogenously dispersed with the form of three-dimensional framework in the gelatin matrix. Porosity development of GBACs was assessed by nitrogen adsorption at −196 °C and their capability of the charge accumulation in the electric double-layer was performed by galvanostatic, voltammetric and impedance spectroscopy techniques. GBACs with various contents of CNTs differ in terms of the total pore volume (from 0.57 to 0.98 cm 3 /g) and Brunauer-Emmett-Teller (BET) surface area (from 1,000 to 1,992 m 2 /g). Very promising specific capacitance values, ranging from 155 F/g to 262 F/g, have been found for GBACs operating in 6 mol/l KOH electrolytic solution. With a moderate content of CNTs, the specific capacitance and electronic conductivity of GBAC are substantially improved because of the combination of increased conductivity, high surface area and electrolyte accessibility of the composite electrode.