Supercapacitor polymer-based electrode

Ion liquid-based gel polymer electrolytes in combination with electronically conducting polymer-based electrodes, such as PEDOT, have been smdied to prepare supercapacitors [113, 114]. For instance, Pandey et al. have characterized devices with specific PEDOT electrode capacitance of-154.5 F g, maximum specific energy of 6.5 Wh kg", and specific power of 11.3 kW kg". ... 

Snook, G.A., Kao, P., Best, A.S., 2011. Conducting-polymer-based supercapacitor devices and electrodes. 

Pandey, G. P., A. C. Rastogi, and C. R. Westgate. 2013. Polyacrylonitrile and 1-ethyl-3-methyliniidazolium thiocyanate based gel polymer electrolyte for solid-state supercapacitors with graphene electrodes. Electrochemical Capacitors 50 145-151. 

G. A. Snook, P. Kao, A. S. Best, Conducting-Polymer-Based Supercapacitor Devices and Electrodes. /. Power Sources 2011,196, 1-12. 

In attempts to improve capacitance over that achieved to date in polymer-based supercapacitors, several groups have investigated EAP-based composites based on PPy [170,173-175], PANI [78,176-178], PT [160,179], PMT [166], and PFPT [160,180,181]. By using a combination of an EAP electrode and an activated carbon electrode, it is possible to produce devices with higher specific power than double-layer capacitors due to the lower equivalent series resistance [166]. In some cases, composite electrodes are a matter of necessity when chemical polymerization is used to produce insoluble polymer powders, the powders can be blended with carbonaceous material and binder. 

These supercapacitors use modified conventional textile material as the base material and then thin active layers of electrodes and electrolyte are applied on it. The textile fabric can also be used as the main active components of the supercapacitor, say the electrode or the separator or the holder of the active elements. If the textile material is used as the base, it is normally modified by adding conductive polymers or metal particles to it by various techniques (coating, printing, deposition, dispersion, or on-site polymerization of conductive polymer). 

Table 4 Conducting polymer based supercapacitor electrode materials with morphology details and deposition technique used.

Electronically conducting polymers (ECPs) such as polyaniline (PANI), polypyrrole (PPy) and po 1 y(3.4-cthy 1 cncdi oxyth iophcnc) (PEDOT) have been applied in supercapacitors, due to their excellent electrochemical properties and lower cost than other ECPs. We demonstrated that multi-walled carbon nanotubes (CNTs) prepared by catalytic decomposition of acetylene in a solid solution are very effective conductivity additives in composite materials based on ECPs. In this paper, we show that a successful application of ECPs in supercapacitor technologies could be possible only in an asymmetric configuration, i.e. with electrodes of different nature. 

Recently supercapacitors are attracting much attention as new power sources complementary to secondary batteries. The term supercapacitors is used for both electrochemical double-layer capacitors (EDLCs) and pseudocapacitors. The EDLCs are based on the double-layer capacitance at carbon electrodes of high specific areas, while the pseudocapacitors are based on the pseudocapacitance of the films of redox oxides (Ru02, Ir02, etc.) or redox polymers (polypyrrole, polythiophene, etc.). 

B. Supercapacitor Based on Electronically Conducting Polymer Electrode... 

In the past five years, many ion conducting polymers and gel electrolytes have been investigated for EDLC application. Figure 15 shows the capacities of various carbon electrodes in SPE or gel electrolytes. The values listed in this figure do not satisfy the requirements for EV. However, it is expected that the requirements of supercapacitors for EV can be achieved by development of devices based on composite electrodes and gel electrolyte systems as described in this chapter. 

A. Yoshizawa, M. Takeda, Y. Oura, Y. Takemoto and K. Naoi, Low-molecular-weight soluble polyaniline for electrolytic capacitor, Electrochemistry, 1999, 67, 45 H. Yamamoto, K. Kanemoto, M. Oshima and I. Isa, Self-healing characteristics of solid electrolytic capacitor with polypyrrole electrolyte, Electrochemistry, 1999, 67, 855 M. Mastragostino, R. Paraventi and A. Zanelli, Supercapacitors based on composite polymer electrodes, J. Electrochem. Soc., 2000,147, 3167. 

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