Synthesis and characterization of anisotropically expanded graphite oxide compounds derived from spherical graphite.

Anisotropically expanded graphite oxide (GO) compounds with controlled interlayer distances were synthesized through the intercalation of various quaternary ammonium cations in GO derived from mesocarbon microbeads (MCMB). It was found that the interlayer distance of the as-prepared anisotropically expanded GO varies with the intercalated cations. In tetrabutylammonium (TBA), tetraoctylammonium (TOA) and dioctadecyldimethyl ammonium (DDA) cation intercalated GO compounds (TBA-GO, TOA-GO, TOA-GO) the corresponding interlayer distances were found to be 1.1 nm, 1.9 nm and 2.9 nm, respectively. Moreover, significant morphology changes were observed for TOA-GO and DDA-GO. Our study suggests that it is possible to tailor both the interlayer distance and morphology of GO by choosing proper intercalated cations. It was also found that the expanded GO compounds show lower water content and improved thermal stability than those of pristine GO. The obtained GO compounds were investigated as electrode material for electrochemical capacitors and all of them delivered typical capacitive behavior.