Synthesis of ordered mesoporous carbon films with a 3D pore structure and the electrochemical performance of electrochemical double layer capacitors

Abstract

Ordered mesoporous carbon films with a 3D pore structure (COU-3) were synthesized by a soft-templating method using resorcinol (R)/formaldehyde (F) as a carbon source and Pluronic F127 as a template agent. The carbon films were prepared by a spin-coating technique. From the results of X-ray diffraction pattern, field emission scanning electron microscope and transmission electron microscope observation, the structure of the COU-3 film was determined to be an Im3m structure whose c-axis is oriented perpendicular to the film surface. The pores run in the directions both perpendicular and parallel to the film surface. The porous structure of the film is different from the ordered mesoporous carbon powders and thick films (COU-1 and COU-2) which were synthesized using the same precursor solution. In the preparation of the COU-3 films, the self-assembly and condensation of a RF-F127 composite immediately occurred during the spin-coating. In this process, the RF-F127 composites are arranged on a substrate surface and an ordered structure spreads from the substrate surface to an upper region. The electrochemical performance of electrochemical double layer capacitor was examined. The CV curves are flat and rectangular in shape, and did not change even at a high scan rate, indicating that the internal resistance in grain boundary and the contact resistance with the substrate can be ignored in the COU-3 film. Additionally, the COU-3 film shows good cycle stability after 250 cycles.