Mesopore-dominant wormhole-like carbon with high supercapacitive performance in organic electrolyte

For designing porous carbon-based electrodes in electric double-layer capacitors (EDLCs), it is crucial to construct a large ion-accessible surface area as well as efficient mass transfer pathways, especially for organic electrolytes with large ion sizes. Here we report the supercapacitive properties of wormhole-like mesoporous carbon (WMC) in both 6 M KOH and 1 M tetraethylammonium tetrafluoroborate (TEABF4) electrolyte. The suitable mesopore size (3.1 nm) of WMC, which is 3 times larger than the solvated ion size of TEABF4, offers a large ion-accessible surface area for charge accumulation. The 3D continuous carbon framework and interconnected mesopore-dominant structure endow the WMC with excellent electron/electrolyte transfer pathways. As a consequence, it presents a small decrease of specific mass capacitance in TEABF4 as compared to that in KOH (174 vs. 189 F g−1, respectively), and a far superior high-rate capability in TEABF4 than most of other porous carbon materials.