Date of Award
Fall 11-29-2018
Document Type
Thesis
Degree Name
Master of Science in Chemistry (MSChem)
Department
Chemistry
First Advisor
Dr: Ram Gupta
Abstract
Nanostructured cobalt sulfide for energy generation and storage applications: Effect of cobalt sulfide phase on electrochemical properties
An Abstract of the Thesis by
May Altammar
Increasing global population has caused increased energy demand for our daily needs such as household appliances, portable electronic devices, automobiles, aerospace vehicles and industrial equipment’s. It is an urgent need of our current technological world to produce and store the energy efficiently and in eco-friendly way. Fuel cells and supercapacitors are among widely used energy conversion and storage devices. To survive our growing needs, this thesis is extensively focused towards advanced energy material with multifunctional capabilities to act as remedial for energy generation and storage material. In this work, nanostructured cobalt based oxides, hydroxides and sulfides were synthesized using a facial hydrothermal method. Phase purity and physical morphology of the synthesized materials were characterized using X-ray diffraction spectroscopy and scanning electron microscopy (SEM), respectively. The electro catalytic performance of the cobalt based materials were analyzed for supercapacitor and water splitting application. The properties of supercapacitance were measured by using three-electrode system. Galvanostatic charge-discharge (CD) and cyclic voltammetry (CV) process were used to investigate the energy storage capacity. While, electrocatalytic water splitting activities were studied by cyclic voltammetry, linear scanning voltammetry (LSV) and electrochemical impedance spectroscopy (EIS).
The optimized cobalt based materials cobalt sulfide Co3S4 exhibited outstanding electrochemical stability with maximum specific capacitance of 12751 mF/cm2 at 2mV/S. The best sample of cobalt based materials showed excellent stability for 5,000 cycles of the charge-discharge study with almost 100% charge retention and coulombic efficiency. In contrast, the electrochemical properties toward hydrogen and Oxygen evaluation reactions required low over-potential of 217 mV and 126 mV at 10 mA/cm2, respectively. Hence, from this work we observed that cobalt sulfide Co3S4 could be a promising multi-functional material for high performance, durable energy generation and storage devices.
Recommended Citation
Altammar, May Yousef, "Nanostructured cobalt sulfide for energy generation and storage applications: Effect of cobalt sulfide phase on electrochemical properties" (2018). Electronic Theses & Dissertations. 380.
https://digitalcommons.pittstate.edu/etd/380