Electrochemical study of the LaNiO3 perovskite-type oxide used as anode in nickel-metal hydride batteries

Abstract

The current work examines the hydrogen storage properties of LaNiO3, a perovskite-type oxide commonly used as a negative electrode in nickel-metal-hydride batteries. In the performed experiments, the LaNiO3 sample was synthesized employing the sol-gel method and its structure and electrochemical characteristics were systematically investigated. Through X-ray diffraction analysis, it was proven that the LaNiO3 material consists of a single phase and crystallizes in the Pm-3m cubic space group. To assess the electrochemical performance of LaNiO, electrochemical measurements were carried out at 298 K utilizing chronopotentiometry, cyclic voltammetry and electrochemical impedance spectroscopy with an electrolyte concentration equal to 6 Mole. As demonstrated by the obtained results, the LaNiO3 electrode required only two cycles to be activated. In fact, it reached its maximum discharge capacity equal to 119 mAh. g−1with a current density of 14.54 mA. g−1. The exchange current density and the Nernst potential were studied by cyclic voltammetry. All electrochemical cycling tests showed that the electrode was activated in the 2ndcycle. It was also noticed that the values of the parameters obtained by the characterization methods evolved in the same way. Moreover, the charge transfer resistance and adsorption resistance were determined using the impedance technique. Overall, this study provides valuable information on the hydrogen storage behavior of the LaNiO3 alloy. These data may be useful for the development of hydrogen storage batteries.