250
Carbon black
200
Carbon nanotubes
150
100
g)
/
50
(F
C
0
–0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
–50
–100
–150
–200
E(V)
128
Electrochemical Supercapacitors for Energy Storage and Delivery
300
250
200
500 nm
0
500
1000
1500
2000
2500
U = 0.8 V
U = 0.6 V
U = 0.4 V
3000
3500
150
100
50
0
Cycle Number
C (F/g)
(a)
(b)
isolation states to ~0.6 V. Figure 3.18 shows that the voltage window is important to the long-term retention of capacitance. Similar results were seen for
PEDOT and Ppy; a 0.4 V window was required to avoid the onset of significant degradation. Symmetric cells made from CNT composites with MnO 2
showed acceptable charging behavior at practical scan rates on the low end
of the spectrum [31]. Figure 3.18 illustrates that this is in opposition to conductive carbon black additives that exhibit resistance. This shows that CNTs
are effective in boosting conductivity and porosity of a charge network to
properly utilize available pseudocapacitance.
FIGURE 3.18
Cyclic voltammograms illustrating effects of CNTs within ECP composite, compared to
using carbon black additives to improve pseudocapacitive efficiency and charge capability.
(Source: Raymundo-Piñero, E. et al. 2005. Journal of the Electrochemical Society, 152, A229. With
permission.)
FIGURE 3.17
(a) SEM image of thin film ECP coating achieved by using CNT support. (b) Increased capacitance loss for PANI at increasing potential cycle range. (Source: Frackowiak, E. et al. 2006.
Journal of Power Sources, 153, 413–418. With permission.)
Carbon black
200
Carbon nanotubes
150
100
g)
/
50
(F
C
0
–0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
–50
–100
–150
–200
E(V)
128
Electrochemical Supercapacitors for Energy Storage and Delivery
300
250
200
500 nm
0
500
1000
1500
2000
2500
U = 0.8 V
U = 0.6 V
U = 0.4 V
3000
3500
150
100
50
0
Cycle Number
C (F/g)
(a)
(b)
isolation states to ~0.6 V. Figure 3.18 shows that the voltage window is important to the long-term retention of capacitance. Similar results were seen for
PEDOT and Ppy; a 0.4 V window was required to avoid the onset of significant degradation. Symmetric cells made from CNT composites with MnO 2
showed acceptable charging behavior at practical scan rates on the low end
of the spectrum [31]. Figure 3.18 illustrates that this is in opposition to conductive carbon black additives that exhibit resistance. This shows that CNTs
are effective in boosting conductivity and porosity of a charge network to
properly utilize available pseudocapacitance.
FIGURE 3.18
Cyclic voltammograms illustrating effects of CNTs within ECP composite, compared to
using carbon black additives to improve pseudocapacitive efficiency and charge capability.
(Source: Raymundo-Piñero, E. et al. 2005. Journal of the Electrochemical Society, 152, A229. With
permission.)
FIGURE 3.17
(a) SEM image of thin film ECP coating achieved by using CNT support. (b) Increased capacitance loss for PANI at increasing potential cycle range. (Source: Frackowiak, E. et al. 2006.
Journal of Power Sources, 153, 413–418. With permission.)