Browsing by Author "Della Noce, Rodrigo"
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- Alpha-Co(OH)(2)/carbon nanofoam composite as electrochemical capacitor electrode operating at 2 V in aqueous mediumPublication . Della Noce, Rodrigo; Eugénio, Sónia; Silva, Maria Teresa Oliveira de Moura e; Carmezim, M. J.; Montemor, Maria de FátimaIn this work, alpha-Co(OH)(2) is electrodeposited onto carbon nanofoam forming a composite electrode operating in a potential window of 2 V in aqueous medium. Prior to electrodeposition, the carbon nanofoam substrate is subjected to a functionalization process, which leads to an increase of about 40% in its specific capacitance value. Formation of cobalt hydroxide clusters onto the functionalized carbon nanofoam by pulse electrodeposition further enhances the specific capacitance of the electrode. The combination of these factors with an enlarged working potential window, results in a material with specific capacitance close to 300 F g(-1) at current density of 1 A g(-1), considering the total mass loading of the composite. This suggests the potential application of the prepared composites in high energy density electrochemical supercapacitors. (c) 2015 Elsevier B.V. All rights reserved.
- Hydrothermally grown Ni0.7Zn0.3O directly on carbon fiber paper substrate as an electrode material for energy storage applicationsPublication . Upadhyay, Kush; Eugénio, Sónia; Della Noce, Rodrigo; Morais Silva, Teresa; M.J. Carmezim; M.F. MontemorNickel oxides because of their excellent electrochemical performance have been considered attractive materials for electrochemical energy storage. However, their application as active material for redox supercapacitor electrodes has been limited by poor electrical conductivity. In order to improve this property, herein we synthesized a nanonet of Ni
Zn-mixed oxide, by facile hydrothermal route, directly on the substrate. The Zn-modified oxide material showed good electrochemical performance, displaying specific capacitance of 770 F g−1 at 1 A g−1 and almost 120% capacitance retention after 2000 cycles of charge discharge at 2 A g−1 in 2 M KOH. Electrochemical impedance results revealed that the Ni0.7Zn0.3O mixed oxide displayed increased conductivity compared to the single NiO material.
- One-step process to form a nickel-based/carbon nanofoam composite supercapacitor electrode using Na2SO4 as an eco-friendly electrolytePublication . Della Noce, Rodrigo; Eugénio, Sónia; Boudard, M.; Rapenne, Laetitia; Moura E Silva, Teresa; Carmezim, Maria; Donne, S. W.; MONTEMOR, FATIMAIn this work, NiOx is anodically electrodeposited onto carbon nanofoam (CNF) to form a composite electrode devoted to supercapacitor applications. The use of NiSO4 as precursor in electrodeposition results in the formation of NiO and NiOOH species, as confirmed by XPS analysis, by means of a one-step anodic process. The presence of both NiO and NiOOH suggests the existence of pseudocapacitance, as observed in MnO2 and RuO2 materials. By employing Na2SO4, an eco-friendly electrolyte, the resulting composite delivers a specific capacitance of 150 F g(-1) at 1 A g(-1) considering the total mass of the electrode (deposit plus substrate). In addition, this composite electrode can operate in a very broad potential window, as high as 2.2 V, suggesting its application in high energy density electrochemical supercapacitors.