Chemistry Reference
In-Depth Information
d
n
3
r
4
n
g
|
4
Figure 9.10
(a-e) CNT-NiO nanoparticle hybrid system. (a) Schematic of the
charging-discharging processes of the hybrid electrode system. SEM
images (side view) of the Ni-decorated VACNTs after various electro-
deposition times: (b) 20 seconds, (c) 2 minutes, (d) 8 minutes. (e) Size
(diameter) variation of Ni nanoparticles with increasing electrodeposi-
tion time. Reprinted with permission from ref. 17. Copyright 2013
American Chemical Society. (f-i) graphene oxide-NiO nanoparticle
hybrid system. Schematics of stacked (f) pristine graphene oxide
nanosheets and (g) NiO nanoparticle-decorated graphene oxide
nanosheets in an electrolyte. SEM images (side view) of stacked
(h) pristine graphene oxide and (i) NiO nanoparticle-decorated
graphene oxide nanosheets. Reproduced from ref. 79.
.
Likewise, pseudocapacitive nanoparticles can be loaded onto 2D nano-
materials such as graphene as well as on 3D mesoporous carbon templates.
Especially in the case of graphene-supported nanoparticles, the addition of
intercalating nanomaterials to the multi-layers of graphene contributes not
only to a straightforward increase of SSA and pseudocapacitance but they
also act as spacers to suppress stacked aggregation of graphene layers
(Figure 9.10(f)-(i)).
79,91
Equivalently, 1D capacitive nanomaterials such as CNTs and pseudoca-
pacitive nanowires can also be applied to other nanomaterials of higher
hierarchy. For instance, Fan et al.
83
reported a significant increase of
SSA (from 202 m
2
g
1
to 612 m
2
g
1
) by growing CNTs on graphene
nanosheets (Figure 9.11(a)-(e)). Interestingly, the cobalt nanoparticles used
for catalytic growth of the CNTs contributed to pseudocapacitance in the
form of cobalt hydroxide. As is the case of intercalating nanoparticles
in graphene layers, the CNTs helped the graphene layers avoid
aggregation during the wet process. They reported 385 F g
1
at a scanning
rate of 10 mV s
1
.
Search WWH ::
Custom Search