Electrically conducting polymers ECPs

Electrically conductive polymer (ECP) blends—maximize performance at minimum levels of ECP incorporation. 

The pseudocapacitance can also be provided by other pseudocapacitive materials such as some metal oxides and electrically conductive polymers (ECPs) that have much higher theoretical capacitance than carbon-based materials. These materials have been reviewed in detail elsewhere [89,90]. Although many materials have been reported to exhibit pseudocapacitive behavior, they are very sensitive to the type and pH of the electrolytes and few of them are suitable for application in strong acid electrolytes. As previously mentioned in Section 1.3.2, RUO2 is one of the most extensively studied pseudocapacitive materials in H2SO4 electrolytes. 

Charge transport in electrically conducting polymers (ECP) is related to the role of easily polarisable delocalised p-electrons, which determines the electrical properties of conducting polymers [75]. Changes in molecular structure due to the localisation of p-electrons and electronic repulsion between the polycations influence the operation of a conducting polymer micro-acutator [76]. 

In order to begin describing electrically conductive polymers, several definitions of conductive polymers must be presented. There are four major classes of conducting polymers filled polymers, ionically conducting polymers, charge-transfer polymers, and electrically conducting polymers (ECPs). 

ECP electrical conducting polymer EMC epoxy molding compound... 

Electrodes of various types are used in hybrid (asymmetric) supercapacitors (HSCs). For example, one of the electrodes is highly dispersed carbon, that is, a double-layer electrode, and the other electrode is a battery one or one of the electrodes is carbon and the other one is a pseudocapacitor, for example, based on electron-conducting polymer (ECP). The main advantage of HSCs as compared EDLCs is an increase in energy density because of the wider potential window. The main fault of HSCs, meanwhile, as compared to electric double-layer capacitors (EDLCs), is a decrease in cyclability following the limitations posed by the nondouble-layer electrode. 

A major draw-back to the use of ECPs as conductive fillers is the instability associated with many of the key properties of these polymers. A number of electrically conducting polymers, such as polyacetylene, are unstable in air over long periods. Thermal stability can be problematical in some ECPs, and would therefore render these polymers unsuitable for use in hot environments. 

Most organic polymers are insulators. However, there are applications requiring dissipation of the electrostatic charge (ESD) or even electrical conductivity (ECP) that would be comparable to that of metals. The ESD materials should have the surface resistivity 10 > R > 10 Q cm. The resistivity of ECP should be 10 > R > lO Q cm. 

By contrast, the ECP must have conjugated rigid-rod macromolecules. Several such polymers show high electrical conductivity (usually after doping), viz. polyacetylene (PAc), polyaniline (PANI), polypyrrole (PPy), polyparaphenylenes (PPP), or poly-3-octyl thiophene (POT). The resins are expensive, difficult to process, brittle and affected by ambient moisture, thus blending is desirable. For uniaxially stretched fibers the percolation threshold is 1.8 vol%, hence low concentration of ECP (usually 5-6 vol%) provides sufficient phase co-continuity to ascertain conductivity similar to that of copper wires (see Table 1.79). 

The electrical conductivity properties of PANI make it probably the most frequently discussed ECP. Developments of this polymer are discussed next in date order [77-80]. 

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