Charge density polypyrrole

Teixidor et al. [49] synthesized self-doped polypyrrole by using the nonconventional covalently bound low charge density anion [3,3 -Co(1,2-C2B9Hio)2] to a pyrrole unit via a spacer diether aliphatic chain. The electropolymerization of the potassium salt of the monomer, denoted as [1] , (Figure 5.7) was obtained in dry acetonitrile with tetrabutyl ammonium chloride in the potential range of —0.5 to 1.7V vs Ag/AgCl. Similarly a copolymer of [1] was prepared with pyrrole monomer (ratio 1 1) under identical conditions. The conductivity of poly[l] and copolymer films measured using a four-point probe... 

C. Masalles, J. Flop, C. Vinas, F. Teixidor, Extraordinary overoxidation resistance increase in self-doped polypyrroles by using nonconventional low charge density anions, Advanced Materials 2002, 14, 826. 

Another polypyrrole/polyamide composite film was obtained by the electrode coating method [84]. In this work the polyamide film was obtained in situ by coating a stainless steel electrode with a polyamic acid film followed by imidization with pyridine and acetic anhydride. The coated electrode was submitted to a constant current in a pyrrole/LiC104 solution in acetonitrile. The surface conductivity measured after detaching the composite film from the electrode showed a strong dependence on the charge density used in the synthesis, i.e. on the amount of pyrrole polymerized in the composite. The maximum value obtained was 2 S cm . Combination of polypyrrole with this polyamide was shown to increase markedly its thermal and environmental stability. 

Masalles, C. Llop, J. Vinas, C. Teixidor, F. 2002b. Overoxidation resistance increase in self-doped polypyrroles by using non-conventional low charge-density anions. Adv. Mater., 14 826-9. 

In a potentiometric process, a wide range of current or charge densities are reported. A typical current density of 0.5 mA/cm, or 30 mC/cm, is a good starting point for exploring optimal plating conditions. It was found that the use of current densities greater than 2 mA/cm resulted in the formation of an overoxidized polypyrrole film with reduced conductivity [79]. 

FIG. 23. Charge discharge curves for nanotubular (a) and thin film (b) LiMn204/ polypyrrole electrodes. Current density = 0.1 mA cm. Electrolyte was 1 M LiC104 in 1 1 (vol.) propylene carbonate dimethoxyethane. 

Keywords-. Li-ion battery, conducting polymers, polyaniline, polypyrrole, polythiophene, graphene, carbon nanotubes, LiFePO, MnO, V Oj, Si, SnO, Fe O, nanocomposites, intercalation, electrolyte, electrode, cathode, anode, energy density, power density, rate capability, voltage, current density, charge/discharge capacity, Nyquist plots, efficiency, cyclability... 

Wu et al. reported a polypyrrole-reduced graphite oxide core-shell composite fabricated through electrostatic interactions, and achieved a capacity of 557 F/g at a current density of 0.5 A/g, with 85% retention of capacity after 1000 charge-discharge processes [43]. 

Panero et al reported the charge-discharge characteristics of Li/LiC104 in a PC/polypyrrole cell [35]. The maximum doping level at a constant current density (0.4 mA cm" ) was 30% (per monomer unit) for a 1 pm thick film, although the value depended on the polypyrrole film thickness. 

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