Influence of the preparation procedure on the electrochemical properties of Pani(DMcT-Cu ion)/carbon fiber composites

Abstract

As propriedades eletroquímicas de compósitos do tipo Pani(DMcT-íon Cu)/fibra de carbono, obtidos eletroquimicamente, são analisadas em função tanto do procedimento de preparação como do sal de cobre (CuCl 2 .2H 2 O ou CuSO 4 ) utilizado para a incorporação de íons Cu 2+ no compósito. Dois procedimentos foram utilizados: adicionando-se o sal de cobre diretamente ao eletrólito durante a eletropolimerização da polianilina (procedimento A), ou adsorvendo-se os íons cobre juntamente com o DMcT sobre a fibra de carbono antes da eletropolimerização (procedimento B). A estabilidade eletroquímica, as propriedades elétricas e a morfologia desses compósitos foram analisadas, por voltametria cíclica, espectroscopia de impedância eletroquímica e microscopia eletrônica de varredura, respectivamente.The electrochemical properties of Pani(DMcT-Cu ion)/carbon fiber composites, obtained by electrochemical means, are analysed as a function of the preparation procedure and the different copper salts (CuCl 2 .2H 2 O or CuSO 4 ) used as source of Cu 2+ ions to be incorporated into the Pani(DMcT)/carbon fiber composite. The composites were prepared according to two procedures: by adding the copper salt directly to the electrolyte during the polyaniline electrosynthesis (procedure A), or by allowing the copper ion to be physically adsorbed onto the carbon fiber prior to the polymer electroformation (procedure B). The electrochemical stability, electrical properties and morphology of the composites were analysed by cyclic voltammetry, electrochemical impedance spectroscopy and scanning electron microscopy, respectively.Keywords: polyaniline, carbon fiber, DMcT, composites, impedance spectroscopy IntroductionIn the recent past decades, the demand for rechargeable batteries has exploded due to the enormous increase in the variety and number of portable devices, especially cellular phones. At the same time, the need has increased for batteries that are smaller, lighter, with higher energy density and more environmentally benign. It is expected that this dependence on batteries as energy sources will become even greater in the future due to an increase in the number of miniaturized devices. Therefore development of novel electrode materials is currently demanded so as to increase the energy density of batteries for different applications, including those for electric vehicles and the load leveling of electric power consumption.Disulfide compounds have been recently proposed as alternative materials for high-energy cathodes in lithium batteries. 1-14 A series of compounds having -SH groups are thought to have a significant potential as energy storage materials, whereby energy exchange occurs according to a reversible polymerization-depolymerization process (2 SH ↔ S-S). 1,2 Among these compounds, 2,5-dimercapto-1,3,4-thiadiazole (DMcT) was first studied by Visco and co-workers 6 as an active cathode material for lithium secondary batteries. However, its redox reaction is too slow at room temperature. Thus, to improve the redox dynamics of DM...

Electropolymerization of polyaniline on high surface area carbon substrates

“…Good results have been obtained with functionalized Pani in gas sensors and corrosion protective coatings [4]. Other examples are the use of Pani combined with Prussian blue as an electrochromic material [5] and the proposition of Pani doped with 2,5-dimercapto-1,3,4-thiadiazole (DMcT) as an alternative material for high-energy cathodes in lithium batteries [6,7].…”

“…Among the carbon substrates found in the literature, carbon fiber (CF) and reticulated vitreous carbon (RVCe) are well known for presenting a high surface area and, therefore, have been used for conducting 0022 polymer deposition [1,7,9]. Films of polypyrrole [1] and polyaniline [7] electrodeposited on carbon fiber substrates presented stable and high discharge capacities when tested as cathodes in lithium rechargeable batteries.…”

“…Films of polypyrrole [1] and polyaniline [7] electrodeposited on carbon fiber substrates presented stable and high discharge capacities when tested as cathodes in lithium rechargeable batteries. For electroanalytical purposes, the effect of the electrodeposition conditions of polypyrrole films on RVCe substrates on the remediation of Cr(VI) in aqueous media has been analyzed [10].…”

“…Furthermore, their differences in the voltammetric, electrical and morphological characteristics are analyzed in terms of the current penetration profile within the RVCe electrode. In addition, due to the different micro-texture of CF and RVCe, a change in the methodology used for polyaniline electrodeposition on CF [7] is proposed for its deposition on RVCe.…”

Selective UV-filter detection with sensors based on stainless steel electrodes modified with polyaniline doped with metal tetrasulfonated phthalocyanine films

“…[14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] Of these polymers, polyaniline (PANI) stands out due to its interesting characteristics such as easy chemical and electrochemical synthesis, high electrical conductivity, and high stability. [29][30][31][32][33] For these reasons, it has been widely employed in sensor and biosensor construction, [34][35][36][37][38][39][40][41][42] amongst other applications. The possibility of preparing PANI films doped with metal tetrasulfonated phthalocyanines (MPcTS), which can be efficiently used as counter-anions to neutralize the polymer backbone, has been suggested by some researchers for use in battery cathodes and other important industrial applications.…”