Yun-Hyuk Choi1,Daehyeon Hong1
Daegu Catholic University1
Yun-Hyuk Choi1,Daehyeon Hong1
Daegu Catholic University1
In 2015, the first high-entropy oxide (HEO), equimolar (Co<sub>0.2</sub>Cu<sub>0.2</sub>Mg<sub>0.2</sub>Ni<sub>0.2</sub>Zn)O was successfully synthesized in a bulk ceramic form by Rost et al. using the conventional solid-state reaction method. The authors synthesized the single-phase rocksalt solid solution by sintering the pellet of the five-component mixed powder (MgO-CoO-NiO-CuO-ZnO) at sufficiently high temperatures. The HEO is a new-type inorganic material composed of multiple metal ions with a single-phase structure, and it reveals unexpected properties of high structural stability and superionic conductivity. In this study, the five-cationic HEOs consisting of new compositions are prepared with changes in crystal structure using the solid-state reaction. As a result, rocksalt, spinel, or their mixed phase were obtained in the HEOs depending on sintering temperature. The structure and composition of the synthesized HEOs have been characterized using various methods such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) method, and X-ray photoelectron spectroscopy (XPS).