Oxygen-deficient NiFe2O4 spinel-type oxide as a electrocatalyst for rechargeable Li-air battery

초록

Lithium-air batteries have received substantial interest as a candidate due to its high theoretical energy density of compared with lithium ion battery. However, despite current efforts for practical applications, side reaction between electrolyte and cathode, sluggish kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), and degradation of electrodes are the obstacles to be overcome for commercialization. In order to achieve an enhanced cell with high activity and stability for ORR and OER, development of an effective electrocatalyst is strongly needed. In this study, Oxygen-deficient NiFe2O4 spinel-type oxide was simply synthesized using hydrothermal method and heat treatment, and was used as an air cathode for a Li-air battery. The surface morphology was examined by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM), respectively. The structure and surface compositions of prepared electrodes were investigated by X-ray diffraction (XRD), energy dispersive spectrometer (EDS), and X-ray photoelectron spectroscopy (XPS). Weight loss and O2 adsorption in samples was determined by thermogravimetric analysis (TGA). The electrochemical characterizations were conducted using a Swagelok-type cell in oxygen atmosphere.