Correlation between the capacitor performance and pore structure of ordered mesoporous carbons

Mesoporous carbons were synthesized by organic–organic self-assembly of triblock copolymer F127 and phenolic resin oligomers composed of resorcinol–formaldehyde or resorcinol–furfural. The mesostructure control was performed by using different polymerization catalysts, ammonia and acetic acid. The effects of the aldehyde and polymerization catalyst on pore architecture of mesoporous carbons were investigated. Disordered mesostructure with poorly disconnected mesopores was formed using furfural. In contrast, when formaldehyde was used, ordered structure with mesochannels was formed. In addition, changes in mesochannel length and the degree of long-range order are found to depend on polymerization catalyst. The porous carbons with different structure were used as a model material to investigate the ion storage/transfer behavior in electrical double-layer capacitor. Electrochemical cyclic voltammetry measurements were conducted in 1 M sulfuric acid electrolyte solution. The ordered mesoporous carbons show superior capacitances and rate performance over the disordered carbons. Electrochemical impedance spectroscopy was used to assess the transport properties. The impedance data clearly demonstrated that the degree of long-range order and channel length can influence the ion transport, resulting in superior capacitive performances.