127
1259
–Z˝(ohm)
–Z˝(ohm)
794
0
5
10
15
20
25
0
1
2
3
4
5
6
100
0.125
0.5
25
63
316
3163
63095
0.79
0
1
2
3
4
5
0
5
1 0
1 5
2 0
2 5
Z´(ohm)
Z´(ohm)
(a)
(b)
40
63
16
0.3
0.125
60
50
30
40
0.04
0.1
4
25
–Z˝(ohm)
20
–Z˝(ohm)
30
20
10
10
0
0
630
0
1 0
2 0
3 0
4 0
0
10
20
30
40
50
60

Z´(ohm)
Z´(ohm)

(c)
(d)

Fundamentals of Electrochemical Pseudocapacitors
FIGURE 3.16
EIS of PEDOT–SS electrode in 1 M oxalic acid at 0.5 V (open circuit potential) after (a) 0, (b)
200, (c) 500, and (d) 1000 charge–discharge cycles All frequency values inside the figure are
in Hz. (Source: Patra, S., and N. Munichandraiah. 2007. Journal of Applied Polymer Science, 106,
1160–1171. With permission.)
networks in the composite that enable rapid diffusion to the high capacitance
pseudocapacitive component. As a result, the composite electrode can provide high capacitance and cycling ability at a practical scale for cell design
[31]. Examples for PANI can be seen in Figure 3.17.
PANI provided the most uniform deposition and morphology, resulting
in a capacitance of ~500 F/g at a 1 V window. It is of interest that in a symmetric two-electrode cell, the capacitance for the material dropped to 250
F/g and the scan window was reduced by the oxygen evolution and charge