Electrodeposition and characterization of nickel–copper metallic foams for application as electrodes for supercapacitors

• Published in: Journal of applied electrochemistry 2014-04, Vol.44 (4), p.455-465
• Main Authors: Eugénio, S., Silva, T. M., Carmezim, M. J., Duarte, R. G., Montemor, M. F.
• Format: Article
• Language: English
• Subjects: Capacitance; CAPACITORS; Chemistry; Chemistry and Materials Science; CURRENT; DEPOSITION; Electrochemistry; ELECTRODEPOSITION; Electrodes; Foamed metals; Foams; Industrial Chemistry/Chemical Engineering; Morphology; Nickel; Physical Chemistry; Research Article
• ISSN: 0021-891X; 1572-8838
• DOI: 10.1007/s10800-013-0646-y

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 .