Mesoporous Carbons Templated by PEO-PCL Block Copolymers as Electrode Materials for Supercapacitors.

Abstract

In this study, samples of activated mesoporous carbon are fabricated with pore structures with cylinder and gyroid nanostructures through the templating effect of amphiphilic poly(ethylene oxide-block-caprolactone) (PEO-PCL) and by using specific resol/PEO-PCL weight ratios (e.g., 60:40 for cylinders; 55:45 for gyroids). After carbonization and KOH activation, the activated mesoporous carbons were tested as electrode materials for electric double-layer capacitor (EDLC) supercapacitors. The electrochemical properties were examined by using three-electrode (6 m KOH(aq) as electrolyte) and CR2032 coin-cell (1 m tetraethylammonium tetrafluoroborate (TEABF4 )/CN as the electrolyte) systems. The gyroid carbon samples provided specific capacitances higher than those of the cylinder carbon samples in both aqueous and organic systems: 155 F g-1 compared with 135 F g-1 in 6 m KOH(aq) , and 105.6 compared with 96 F g-1 in 1 m TEABF4 /MeCN, after 100 charge/discharge cycles. It is suspected that the bi-continuous mesochannels of the gyroid-type activated mesoporous carbons provided a relatively higher effective adsorption surface area; in other words, the greater surface area for energy storage originated from a moderate pore size and an interconnected pore structure.