Microscopic and Spectroscopic Characterization Equipment

Get Complete Project Material File(s) Now! »

Global Interest in Renewable Energy

Today’s society is highly dependent on hydrocarbons as the primary source of energy due to their low cost as well as high specific energy and power per weight or per volume. Nevertheless, there exists a change in energy paradigm due to the growth in civilization as well as more countries in the developing world seeking an improved standard of living, hence, generating high energy demand. Therefore, the development of technology that is compatible with the resources provided by nature is essential to have sustainable development. According to the International Energy Outlook 2013 (IEO2013) [1], Global energy use will continue to rise rapidly with total world consumption jumping from 524 quadrillion British thermal units (BTUs) in 2010 to an estimated 820 quadrillion in 2040. A net increase of 56% (BTU represents the amount of energy needed to heat one pound of water by one degree Fahrenheit). As a result, every country across the globe put a lot of effort in innovation towards sustainable and renewable energy. The term “renewable energy” is defined in several ways, but generally, it refers to those energy resources and technologies whose common characteristic is that they are non-depletable or naturally replenishable [2]. The definition of renewable energy according to the International Energy Agency is as follows: “The energy derived from natural processes that replenish constantly. In its various forms, it derives directly or indirectly from the sun, or from heat generated within the earth. Also defined as the energy generated from solar, wind, biomass, geothermal, hydropower and ocean resources” [3]. Fig. 1.1 indicates some of the examples of the modernized technologies in renewable energy applications. Out of these distinguished types of renewable energies, wind and solar (PVs) are the most feasible and can be scaled accordingly, in almost any part of the world, to provide power. The challenge with these technologies is their inability to store the as-produced energy, thus placing ECs and other electrochemical energy storage devices (i.e., Batteries) of national and strategic significance in a highly competitive international market.
Although petroleum and other liquids remain the largest source of energy, the liquid fuels share of world marketed energy consumption falls from 34 percent in 2010 to 28 percent in 2040. Therefore, fossil fuels are expected to continue supplying much of the energy worldwide. Unfortunately, this type of energy supply provides hostility to the environment. Thus, renewable energy and nuclear power have been observed to be the world’s fastest-growing energy sources, each increasing by 2.5 percent per year; even though fossil fuels continue to supply almost 80 percent of the global energy use through 2040, (see fig. 1.2). It is indeed a fact that from the discovery and exploitation of fossil fuels, and the result of profound scientific and technological innovations, life has been exceedingly comfortable over the past two centuries regarding energy reliability. But we cannot shy away from the fact that we are on course to consume these non-renewable energy sources within several hundreds of years and also avoid the unknown medium-to-long term implications of burning carbonaceous fuels and CO2 emissions that continue being harmful to the environment. Hence, it is evident that scientific and technological interference are necessary with renewable energy resources at the forefront. Thus, creating a major demand for alternative energy storage mechanism that will be coupled together with the renewables [5].

Energy Storage Systems (ESS)

As much as the renewable energy shows to be the escalating solution towards the uprising cruelty to the environment, a key stumbling block in renewables is the technical difficulties of electricity storage and transmission. Grid energy storage is a critical component of the integration of renewable technologies and ensuring reliable distribution of electricity [6]. But the August 2003 blackout in the Northeast, the September 2011 power failure that extended from Southern California to Mexico and Arizona and 2008-2015 loads shedding by ESKOM electricity grid in South Africa are more widely publicized examples in which power outages affected and still continue to affect many millions of consumers across the globe. From a broader perspective, such power outage events underscore the complex set of issues associated with the generation and use of electricity as well as the use of Grid to store energy [7]. Indeed, EES can be seen as an established, valuable approach for improving the reliability and overall use of the entire power system (see fig. 1.3). EES technology is attractive for providing many grid services, and also, it can deliver services to solve more localized power quality issues and reactive power support [8]. It is evident that the synergy between the energy storage systems and renewable energy resources will be a major contributor to resolving the current energy crisis..

Electrochemical Energy Storage Systems (EESs)

The implementation of renewable energy sources, such as solar or wind power, causes paramount challenges to power grid management and stability due to their significant fluctuations in electricity generation due to high energy demand. A shift towards the establishment of various technologies is being developed to complement the existing ones to achieve this task, ranging from mechanical, physical, thermal, chemical, and electrochemical energy storage systems. In considering a reliable, stable, and sustainable large-scale use of renewables, electrochemical capacitors (ECs) and batteries play a fundamental role in advanced and highly efficient energy storage and management [9]. Thus, EES in the form of electrochemical capacitors (ECs) and batteries can be used not only as a backup energy supply but also as the power source for smaller devices such as laptops, cell phones and in medical implants. They are also used as pacemakers, defibrillators, and also in transportation such as electric vehicles, defence, or aerospace applications (see fig. 1.4) [10]. Batteries and ECs are now a commodity of national and strategic significance in a highly competitive international arena [11].

Electrochemical energy storage systems characterize an opportunity for fundamental

and applied researchers to overcome collectively challenging scientific and technological barriers that directly address a critical societal and environmental necessity. In particular, development of high energy and power density ECs and batteries that are safe to operate in an environmental premise could make a global electrified transportation industry a reality. ECs can be used together with LIBs for their high power attribute to compliment LIBs that possesses relatively high energy density, or they can be utilized independently as new research demonstrates that these energy storage systems have good energy density. Therefore, research and development in the field of ECs are focused on increasing the energy density of these energy storage systems as well as their stability [5], [14], [15].

The Objectives / Scope of this Study

Their high power densities characterise ECs with moderate to low energy densities, and widely used in most of today’s portable electronics and electric vehicles (EVs). But unfortunately, regardless of their commercial success, ECs still fall short of satisfying high energy needs for applications such as power tools and efficient utilisation of renewable energies such as solar and wind power. The performance of ECs is intimately dependent on the properties of their electrode materials; as such it is not surprising that greater attention is devoted to research and development of electrode materials [16]. There is a need to improve substantially their performance such as cycle stability, safety, high energy density and cost to meet the requirements of future systems. Breakthroughs in the development of new materials hold the key to new generations of ECs as against the status quo. Such materials will lead to the development of ECs that can meet the current needs (i.e., safety, affordability, with high energy and stability for

use in mobile electronic devices and large scale devices). The demand for high power

capabilities (especially for more major system applications), full capacity retention, high charging rate, lowering of cost, safety issues and ensuring a constant supply of power can be achieved. One of the main parameters playing a role in the development of ECs is the surface area of the electrodes, pore volume, and pore distribution which makes nanosizing of electrode material an important part of this research. Nanoscale design of the structure and chemistry of electrode materials may enable researchers/scientist to develop a new generation of devices that approach the theoretical limit for electrochemical storage and deliver electrical energy rapidly and efficiently [17]. Nanomaterials of about the length scale of less than 100 nm, have received increasing interest owing to their fundamental scientific significance as well as their potential applications that derive from their fascinating electrical, magnetic, and catalytic properties [18]. The manganese oxide based (MnO) materials (e.g., MnO2 and Mn3O4) and carbon nanomaterials (e.g., carbon nanotubes (CNTs), onion-like carbons (OLCs) and graphene) are well recognised for their environmental friendliness and are safer compared to other materials such as RuO2. Therefore, the use of such nanomaterials in ECs is a very attractive quest for research due to availability in nature [19]–[21].
Since the development of high-performance ECs is at the forefront of energy research globally, it has been shown that the capacitance and lifetime of electrodes are controlled by the (i) synthesis method, (ii) the size and type of the electrode material, and (iii) the nature of the electrolyte involved. Thus, the primary objectives of this thesis are as follows: I. To synthesise single phase birnessite-type MnO2 on to various carbon allotropes (i.e., OLC, CNT, GO, and AC) and forming carbon/MnO2 nanohybrids using simple chemistry technique of reflux. $Outline of the Dissertation This dissertation is divided into seven chapters with Chapter 1 discussing the increasing demand for energy and the hostile implications of the use of the current power source. This chapter also touches on renewable energy and how it affects society today and in the future. In this section, electrochemical energy storage, and its dynamic growth is put into perspective. Chapter 2 is a literature review that gives a broad background in electrochemistry and the core principles of ECs with the three different types of ECs discussed in a detailed form. Different electrode materials are reviewed in a more comprehensive way in this chapter. Brief overviews of the techniques used for microscopic, spectroscopic and electrochemical analysis are presented. In Chapter 3, the experimental techniques and methods are presented. This chapter also discusses a synthetic procedure of various MnxOy-based nanohybrid materials and GO-NiTAPc composite. The fabrications of electrochemical cells with electrode materials are presented. Chapter 4-6 reports on the results obtained in the study. Chapter 7 gives concluding remarks showing the significance of this study and also paves the way forward with some recommendations and possible future work.

Table of Content :

• Declaration
• Dedication
• Acknowledgements
• Abstract
• Table of Content
• List of Abbreviations and Symbols
• List of Tables
• List of Figures
• 1 CHAPTER 1: INTRODUCTION
  • 1.1 Global Interest in Renewable Energy
  • 1.2 Energy Storage Systems (ESS)
  • 1.3 Electrochemical Energy Storage Systems (EESs)
  • 1.4 The Objectives / Scope of this Study
  • 1.5 Outline of the Dissertation
  • References
• 2 CHAPTER 2: LITERATURE STUDIES / BACKGROUND
  • 2.1 Electrochemical Capacitors (ECs): An Overview
  • 2.2 Historical Background of Electrochemical Capacitors (ECs)
  • 2.3 Basic Principles of Electrochemical Capacitors (ECs)
    • 2.3.1 Energy Storage in Electrical Double Layer Capacitors (EDLCs)
    • 2.3.2 Energy Storage in Pseudocapacitors (PCs)
    • 2.3.3 Energy Storage in Hybrid Capacitors (HCs)
    • 2.3.4 Performance of Electrochemical Capacitors (ECs)
  • 2.4 Electrode Materials for the ECs
  • 2.4.1 Carbon Structure and Porous Texture on EDLC Performance
  • a) Activated Carbon
  • b) Graphene and Graphene Oxide
  • c) Carbon Nanotubes (CNTs)
  • d) Onion-like Carbons (OLCs)
  • 2.4.2 Transition Metal Oxide (i.e., MnxOy) as Pseudocapacitor Materials
  • a) MnO
  • b) Mn3O
  • c) Mn2O
  • 2.4.3 Transition Metallophthalocyanines (i.e., MPc) as Pseudocapacitor Materials
  • 2.5 Electrochemical Characterization Techniques for ECs Applications
  • 2.5.1 Cyclic Voltammetry (CV)
  • 2.5.2 Galvanostatic Charge-Discharge (GCD)
  • 2.5.3 Electrochemical Impedance Spectroscopy (EIS)
  • 2.6 Microscopic, Spectroscopic and Thermal Characterization Techniques for
  • Energy Storage Electrodes In ECs Application
    • 2.6.1 Scanning Electron Microscopy (SEM)
    • 2.6.2 Transmission Electron Microscopy (TEM)
    • 2.6.3 Energy Dispersive X-ray Spectroscopy (EDX)
    • 2.6.4 X-Ray Diffraction (XRD)
    • 2.6.5 X-Ray Photoelectron Spectroscopy (XPS)
    • 2.6.6 Infrared Spectroscopy
    • 2.6.7 Gas Adsorption Technique
    • 2.6.8 Raman Spectroscopy
    • 2.6.9 Thermo-Gravimetric Analysis (TGA)
  • Reference
• 3 Chapter 3: Experimental Techniques and Methods
  • 3.1 Materials and Reagents
  • 3.2 Synthesis of Materials
    • 3.2.1 Synthesis of Onion-Like Carbon (OLC)
    • 3.2.2 Functionalization of Multiwalled carbon nanotubes (CNT)
    • 3.2.3 Synthesis of Graphene Oxide (GO)
    • 3.2.4 Synthesis of Carbon/Birnessite-MnO2 Nanohybrid
    • 3.2.5 Synthesis of Hausmannite Mn3O4 and Carbon/Hausmannite Mn3O4 Nanohybrid
    • 3.2.6 Synthesis of NiTAPc and GO/NiTAPc
  • 3.3 Microscopic and Spectroscopic Characterization Equipment
    • 3.3.1 Scanning Electron Microscopy (SEM)
    • 3.3.2 Energy dispersive X-ray spectra (EDX)
    • 3.3.3 Transmission electron microscopy (TEM)
    • 3.3.4 X-ray diffraction (XRD)
    • 3.3.5 Raman Analysis
    • 3.3.6 Fourier infrared spectroscopy (FTIR)
    • 3.3.7 X-ray photoelectron spectroscopy (XPS)
    • 3.3.8 Nitrogen gas sorption
  • 3.4 Electrochemical Characterization Procedure
  • 3.4.1 Fabrication of Carbon/MnO2 Nanohybrid Electrodes for Electrochemical Capacitors
  • 3.4.2 Electrochemical Procedure
  • References
• 4 Chapter 4: Carbon/birnessite-type Manganese Oxide (C/MnO2) Nanohybrids as Pseudocapacitor Materials
  • 4.1 Introduction
  • 4.2 Results and Discussion
    • 4.2.1 SEM and TEM analysis
    • 4.2.2 XRD, Raman, FTIR, EDX, and XPS studies
    • 4.2.3 Cyclic Voltammetric (CV) analysis of various carbon-MnO2 based electrodes on Ni foam
  • 4.2.4 Galvanostatic Charge-Discharge (GCD) analysis of various carbon-MnO2 based electrodes on Ni foam
  • 4.2.5 Electrochemical Impedance Spectroscopy (EIS) analysis of various carbon MnO2 based electrodes on Ni foam
  • 4.2.6 TGA and Gas sorption analysis
  • 4.3 Conclusion
  • References
• 5 Chapter 5: Carbon/hausmannite-type manganese oxide (C/Mn3O4) nanohybrids as pseudocapacitor materials
  • 5.1 Introduction
  • 5.2 Results and Discussion
  • 5.2.1 SEM and TEM analysis
  • 5.2.2 XRD, Raman, FTIR, EDX, and XPS studies
  • 5.2.3 Cyclic Voltammetric (CV) analysis of various carbon/Mn3O4-based electrodes on Ni foam
  • 5.2.4 Galvanostatic Charge-Discharge (GCD) analysis of various carbon/Mn3O4-based electrodes on Ni foam
  • 5.2.5 Electrochemical Impedance Spectroscopy (EIS) analysis of various carbon/Mn3O4 based electrodes on Ni foam
  • 5.3 Conclusion
  • References
• 6 Chapter 6: Graphene Oxide /Nickel (II) Tetraaminophthalocyanine (GO/NiTAPc) Composite as Pseudocapacitor Material
  • 6.1 Introduction
  • 6.2 Results and Discussion
  • 6.2.1 SEM, TEM, XRD and UV-vis analysis
  • 6.2.2 The comparative electrochemical performance of GO/NiTAPc electrode material
  • 6.3 Conclusion
  • References
• 7 Chapter 7: General Conclusion and Recommendations
  • 7.1 Concluding Remarks
  • 7.2 Recommendations for Further Research
  • Appendix A
  • Appendix B

GET THE COMPLETE PROJECT