Effects of macropore size on structural and electrochemical properties of hierarchical porous carbons

Hierarchical porous carbons (HPCs) were synthesized by a colloid crystal template method with phenolic resin as carbon source and triblock copolymer Pluronic F127 as a soft template. The obtained HPCs with tunable macropore size of 242-420 nm exhibit large BET surface areas (similar to 900 m(2) g(-1)) and large pore volumes (similar to 1.2 cm(3) g(-1)). With an increase in the diameters of silica template, the BET surface areas and pore volumes of HPCs decrease. The electrochemical properties of the HPCs with various macropore sizes used as supercapacitor electrodes materials were evaluated using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy techniques. The results show the HPC with the macropore size of 242 nm possesses the largest specific capacitance among the HPCs. The excellent capacitive behavior of HPC-242 can be attributed to its faster ion transport behavior and better ion-accessible surface area.