We have developed a super capacitor electrode using as-grown single-walled carbon nanotubes (SWCNTs), synthesized by water-assisted chemical vapor deposition. The aligned SWCNT ensembles have better electronic and ionic conductivities compared to activated carbon (AC) due to their cohesion, crystallinity, and absence of filling/binder material. Specifically by fabricating electrodes purely from SWCNTs, with high carbon purity (99.98 %), a higher voltage range of 4 V is achieved compared to only 3 V for AC. Additionally these SWCNT electrodes maintain durability (3.6 % decline over 1000 cycles at 4 V).

Furthermore, due to their high electronic conductivity, the SWCNT electrodes can operate without full coverage by metal current-collectors, thus enabling significant device weight reduction. The performance of a SWCNT device without current-collectors is estimated for an energy density at 17 Wh/kg and for a maximum power density rating at 24 kW/kg.