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Pore structures and electrochemical performances of mass-produced metal-free single-walled carbon nanotubes (mf-SWCNTs) heated in either CO 2 gas or dry air were investigated. Pore structures, defects, and electrochemical performances of mf-SWCNTs were analyzed mainly using the N 2 adsorption method, apparent density measurement, Raman spectroscopy, and cyclic voltammogram. mf-SWCNT sheets heated in CO 2 gas showed a remarkable increase of the specific surface area up to 1900 m 2 g -1 , but sheets heated in air showed an increase of only up to 1400 m 2 g -1 . Propan-2-ol, 4-methyl-1,3-dioxolan-2-one, or ionic liquid was impregnated in the inner space of mf-SWCNTs to confirm whether the inner space of mf-SWCNTs is filled with each liquid. mf-SWCNTs heated in air were completely filled, but mf-SWCNTs heated in CO 2 were partially filled. From these results, it is estimated that holes of the size of 0.56 nm or larger are opened on the side wall of mf-SWCNTs. A combination of two heat treatments maximized the effective specific capacitance of heated mf-SWCNTs up to 100 F g -1 , which is 1.6 times higher than that of as-grown mf-SWCNTs because of the removal of the carboneous component and the creation of defects on the sidewall of mf-SWCNTs, which allow the electrolyte into the inner space of mf-SWCNTs.

Nitrogen-enriched mesoporous carbon which has been successfully prepared from quinoline-polymerized pitch using mesoporous silica as a template denoted ordered hexagonal assembly of fibrous carbon having ca. 6–7 nm in diameter and higher capacitance amounting to 200–300 F·g−1 in H2SO4 electrolyte than ordinary mesoporous carbons prepared using divinylbenzene as a carbon precursor (<180 F·g−1).

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