Eletrodos à base de NiO para armazenamento de energia: síntese, microestrutura e caracterização eletroquímica

Abstract

Due to increasing energy demand and increasing scarcity of natural energy resources, the world is gearing up for an era of rising energy costs. In response to this worldwide concern, the use of energy from renewable sources and how to store it has become a focus of research among the scientific community. NiO and its composites are widely used in energy storage devices, mainly due to their high electrochemical activity. However, the evaluation of the battery-like behavior of NiO-based systems seems to be somewhat neglected in the literature. The purpose of this work was to study nickel oxide as a potential material for energy storage. NiO powders were obtained using the citrate, nitrate calcination, combustion and protein sol-gel methods. The structure and size of the particles of the calcined powders were investigated by XRD and scanning electron microscopy (SEM), respectively. The network parameters were determined by Rietveld refinement of the diffraction data. The electrochemical performance of the powders was evaluated by cyclic voltammetry, galvanostatic charge-discharge and impedance spectroscopy. The electrochemical results highlight the electrode obtained by the nitrate calcination method as the one with the highest specific storage capacity according to GCD curves (45.25 C / g at 5 mV / s). The impedance results showed similar serial resistance values for the powders obtained by the calcination method of nitrate and citrate, about 0.22 Ω.