Title : Effect of Heat Treatment on the Electrochemical Properties of Mn Oxide-Based Powder Prepared Using a Wet Chemical Process
Authors: Woo Won Chun, Myung Sik Shin, Bit Na Choi, Aniu Qian, Jong Wook Bae, and Chan-Hwa Chung

Journal : Science of Advanced Materials
Vol/No/Page : 8/1/89-95
DOI : 10.1166/sam.2016.2609

Abstract :
Manganese oxide-based powder was synthesized through a wet chemical process using manganese(II) chloride tetrahydrate. The powder was heat-treated for five hours at temperatures ranging from 200 C to 800 C. Based on the scanning electron microscopy (SEM) analysis, as the heat treatment temperature increased, the surface roughness increased. In addition, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses confirmed that, as the heat treatment temperature increased, the oxidized state of manganese changed from Mn3O4 to Mn5O8 and then to Mn2O3. Electrodes were fabricated using the individual manganese oxide-based powders and analyzed via half-cell cyclic voltammetry (CV) on the basis of 5 mVs−1. The sample heat-treated at 200 C showed the highest performance with a specific capacitance value of 207.4 Fg−1 and was identified as having the best electrode characteristics, as determined by charge–discharge tests and electrochemical impedance spectroscopy (EIS) analysis.