| 초록 |
Macroscopic morphology of carbon nanotubes (CNTs) was designed using emulsion droplet confinement. Spherical CNT assemblies (CNT balls), were produced by the evaporation of CNT-dispersed aqueous emulsion droplets in oil. CNT was packed by the capillary pressure. With changing the concentration of CNT dispersion, the size of CNT balls could be controlled. Average size of CNT balls ca.10um with BET specific area of 200m2/g. CNT balls were heat-treated to remove residual solvent. When heat-treat at high temperature, the surface oxygenated groups were decomposed. CNT ball-assembled film was applied to a supercapacitor. The specific capacitance of 500°C treated ball was 80F/g, a higher temperature decreased the capacitance with decreasing the pseudo-capacitance. Comparing with CNT films, the CNT ball electrode showed 40% higher specific capacitance with higher rate performance, attributed to the compact packing of CNTs and ball and the hierarchical porous structures in the ball assemblies. |
