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Resumo(s)
Nickel-copper metallic foams were electrodeposited from an acidic electrolyte, using hydrogen bubble evolution as a dynamic template. Their morphology and chemical composition was studied by scanning electron microscopy and related to the deposition parameters (applied current density and deposition time). For high currents densities (above 1 A cm(-2)) the nickel-copper deposits have a three-dimensional foam-like morphology with randomly distributed nearly-circular pores whose walls present an open dendritic structure. The nickel-copper foams are crystalline and composed of pure nickel and a copper-rich phase containing nickel in solid solution. The electrochemical behaviour of the material was studied by cyclic voltammetry and chronopotentiometry (charge-discharge curves) aiming at its application as a positive electrode for supercapacitors. Cyclic voltammograms showed that the Ni-Cu foams have a pseudocapacitive behaviour. The specific capacitance was calculated from charge-discharge data and the best value (105 F g(-1) at 1 mA cm(-2)) was obtained for nickel-copper foams deposited at 1.8 A cm(-2) for 180 s. Cycling stability of these foams was also assessed and they present a 90 % capacitance retention after 10,000 cycles at 10 mA cm(-2).
Descrição
Palavras-chave
Nickel-copper Nanostructured foams Electrodeposition Electrodes for supercapacitors
Contexto Educativo
Citação
EUGÉNIO, S,; SILVA, T. M.; CARMEZIM, M. J.; DUARTE, R. G.; MONTEMOR, M. F. - Electrodeposition and characterization of nickel–copper metallic foams for application as electrodes for supercapacitors. Journal of Applied Electrochemistry . ISSN 0021-891X. Vol. 44, nr. 4 (2014), p. 455-465.