SYNTHESIS, CHARACTERIZATION AND PSEUDO-CAPACITIVE PERFORMANCE OF MANGANESE OXIDE NANOSTRUCTURES

Author

Chung-Ying Tsai, Southern Illinois University CarbondaleFollow

Date of Award

12-1-2012

Degree Name

Master of Science

Department

Mechanical Engineering

First Advisor

Mondal, Kanchan

Abstract

In this research, manganese oxide based nanoparticles were synthesized by sol-gel process. Methanol, ethanol, and propanol were used as alternative solvents during sol-gel process with manganese acetate as precursor for the preparation of pristine manganese oxide. Hybrid manganese oxide modified by additions of carbon nanotubes was further prepared. The effects of different solutions and heat treatment temperatures on the morphology, physical characteristics, and electrochemical properties of the manganese oxide based materials were investigated. Particle size of pristine manganese oxide samples prepared from methanol, ethanol, and propanol were compared by SEM and TEM image analysis. Smallest particle size was observed for manganese oxide prepared from propanol, with diameters range from 16 nm to 50nm. XRD results showed that the as-prepared manganese oxide based samples treated at calcination temperature of 300ºC and above were composed of Mn₂O₃ as dominant phase, with Mn₃O₄ as minor phase. Specific capacitance of manganese oxide prepared from methanol, ethanol, and propanol at scan rate of 10 mV/s measured using two electrode systems were 88.3, 66.0, and 104.8 F/g, respectively and that for the hybrid sample was 140.5 F/g. Results from electrochemical impedance spectroscopy (EIS) also showed superior electrochemical properties of the hybrid sample over pristine manganese oxide samples. It is evident that the addition of carbon nanotubes not only improved the specific capacitance but also the overall electrochemical properties of the manganese oxide supercapacitor.