Synthesis and characterization of nano-structured α-MnO2/Co3O4 metal oxide for energy storage application

Abstract

A capacitor is a passive terminal electrical device that is used to store electrostatic energy in the form of electric field separated by a dielectric, but as a drawback, this device is not able to hold a large energy that is our primary focus and concern in response to the changing global high energy demand and needs in the future. Looking into the concern of future global energy crisis, a device that can solve our energy storage related problem is the supercapacitor which has matured significantly over the last decade and emerged with the potential to facilitate major advances in energy storage. More importantly, a supercapacitor has a large capacitance ( in farad ) which is approx. thousands times larger than a simple electrolytic capacitor and can full fill our future energy storage requirement due to having high power density, fast charging and discharging, and long service life as compared to batteries. Not only this, supercapacitors have many applications such as they are widely used in renewable energy power plant, memory back-up devices and hybrid electrical vehicles etc. Here we report the synthesis and supercapacitive property of Manganese dioxide (a-MnO2) and its hybrid with Cobalt oxide (Co3O4) nanostructure synthesized by hydrothermal method. We also performed several characterizations such as; X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Brunauer Emmett Teller (BET), UV-Visible spectroscopy, Infrared spectroscopy to know about the purity, crystal structure, morphology and surface related information of the desired nanostructure. The electrochemical characterization of a-MnO2 resulted the capacitance of 570 F/g at the scan rate of 1mV/s whereas hybridized a- MnO2/Co3O4 exhibited an enhanced capacitance of 1802 F/g. The material shows an excellent stability and capacitive retention of 96.5% after 2000 cycles. Hence these electrochemical results of a-MnO2 and Co3O4 hybrid nanostructured demonstrate its application for energy storage devices.