Page 272 - Carbon Nanotube Fibres and Yarns

262 Carbon Nanotube Fibers and Yarns

Fig. 10.9 (A, B) Photos of woven fabric embedded with threadlike SCs, (C, D) Schematics
of threadlike SCs connected in series and parallel, (E) CV curves and (F) GCD curves of
the two threadlike SCs connected in series and parallel. (Reproduced with permission
from Y. Li, X. Yan, X. Zheng, H. Si, M. Li, Y. Liu, Y. Sun, Y. Jiang, Y. Zhang, J. Mater. Chem. A 4
(2016) 17704–17710.)

which was coated with a polymer gel and then wrapped with a CNT sheet
(Fig. 10.10A and B) [92]. The inner CNT fiber and the CNT wrapper
formed the two electrodes of the asymmetric supercapacitor. This device
structure reduced the contact resistance between the two electrodes, as
shown by the lower internal resistance in the Nyquist plots (Fig. 10.10C).
−1
−3
The SC achieved a high capacitance of 59 F/g (32.09 F cm , 29 μF cm or
−2
8.66 mF cm ), 12 times higher than its two-ply CNT yarn supercapaci-
tor counterpart (4.5 F/g). The coaxial SC exhibited energy density up to
−1
−1
1.88 Wh kg and power density of 755.9 W kg .
Chen et al. also developed a novel threadlike asymmetric SC with a
higher volumetric energy density using CNT fiber as the flexible and con-
ductive substrate [93]. Fig. 10.10D shows a schematic of the fabrication
process. The positive electrode was produced by growing MnO 2 nanosheets
onto a conducting polymer-coated carbon nanotube fiber while the nega-
tive electrode was an ordered microporous carbon/carbon nanotube hybrid