Síntese e caracterização da mistura ternária de óxidos Ni- Co-Sn para aplicações em capacitores eletroquímicos

Abstract

Modern society depends on electricity, which accounts for approximately 60% of all transformed primary energy. The concern with the obtaining and consumption of the electric energy in order to sustain the development pass through the sources of renewable energies where the systems of storage of electric energy has assumed great importance. The electrochemical capacitors are devices that depending on the materials used in their electrodes can directly store electrical energy through electrostatic adsorption / desorption, and indirectly through oxidation / reduction reactions. In general, when the storage is direct, they are called double-layer electric capacitors, and when it is indirect, they are called pseudocapacitors. In this sense, the thesis proposal was to study the synthesis of Ni-Co-Sn ternary oxide in the forms of film and powder by the method of the polymeric precursors, where the oxide was synthesized on an inert substrate / electrode. The ternary oxide was studied in different salt compositions, different molar compositions of citric acid and ethylene glycol, and evaluated for different calcination temperatures. In the form of film, the ternary oxide presented better capacitive performance in the composition Ni50, in molar composition of resin 1: 3: 12 and in the calcination temperature of 400 ºC. SEM images showed the formation of a film showing cracks and cracks. The diffractograms indicated the present phases that presented sizes of crystallites in a nometric scale. The voltammograms clearly showed oxidation and reduction peaks, characteristic of pseudocapacitive behavior. Through the electrochemical impedance spectra were identified the resistive processes and their variations during the stability test. The charge and discharge curves showed a high value for the specific capacitance of the electrode in the form of a film of 320,6 F g-1. The method used possibility obtaining the ternary mixture in the forms of film and powder with excellent electrochemical properties aimed at energy storage.