Caracterização eletroquímica de material ativo de eletrodo de supercapacitor baseado em nanocompósito de nanotubos de carbono e óxido de níquel

• Autor(a) principal: Franco, Juliana Rodrigues
• Data de Publicação: 2014
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/961
• topic: Eletroquímica; Capacitores; Eletrodo; Eletróidio; Energia - Armazenamento; Electrochemistry; Capacitors; Electrode; Eletróidio; Energy - Storage; CNPQ::CIENCIAS EXATAS E DA TERRA::FISICA::FISICA DA MATERIA CONDENSADA

Motivated by the current demand of storage devices more energy efficient and sustainable, in this work were manufactured electrodes for supercapacitor based on carbon nanotubes (CNT) and nickel oxide (NiO) nanocomposites supported on indium tin oxide (ITO) substrate. Electrochemical capacitors, knowed as supercapacitors, are energy storage devices characterized by their high energy density, high power density, long life cycle and short charge and discharge time. In this context, nanocomposites based on carbon nanotubes and metal oxides can exhibit excellent electrochemical performance in applications for supercapacitor electrodes. The total capacitance of electrode nanocomposite is the addition of both contributions: the high capacitance of the electric double layer, due to high specific surface area of carbon nanotubes and pseudocapacitance performance of nickel oxide, due stored energy electrochemically by faradaic processes. There are several metal oxides that have pseudocapacitive features, but many are too expensive. The nickel oxide has a comparable performance with other pseudocapacitive oxides and conductive polymers, and have a low cost. To produce the NiO/CNT/ITO electrodes in this work, first nanotube films were prepared by electrophoretic deposition on ITO substrate. Then nickel metallic was electrodeposited on the nanotubes, and finally the electrode passed through a thermal treatment to form the oxide. The NiO/CNT/ITO electrode developed in this study showed a high electrochemical performance for the potential ranging from 0.0 V to 0.8 V, with ~ 35 F/g of maximum capacitance. This nanocomposite showed ~ 15 kJ/kg of maximum power densities and ~ 5 kW/kg of maximum power. These densities are consistent with expected values for supercapacitors according to the Ragone Plot. Moreover, this nanostructured electrode showed higher cyclic stability than oxide without carbon nanotubes. These properties make this nanocomposite a promising material for the development of high energy density and high power density supercapacitors devices.