- Title
- Direct synthesis of mesoporous fullerene hybrids for energy storage applications
- Creator
- Baskar, Arun Vijay
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2020
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- The increasing population and the pollution caused by the aggressive usage of fossil fuels has created an urgency for devising alternative sources of energy production that could deliver high energy outputs without any deteriorating effect on the global climate. Once produced, the energy needs to be stored and safely transported to the consumers. Energy storage devices such as supercapacitors and batteries are considered as sustainable resources that could deliver a high energy and high power density without leaving any environmental footprints. There are continuous efforts to design supercapacitors and batteries with enhanced performance that relies mostly on the materials used for fabricating the electrodes. The design of advanced electrode materials with tuneable textural properties such as high surface area and high pore volume along with high conductivity is a highly sought after proposition. Carbon is a preferred choice for electrode material and several carbon-based materials such as CNTs, graphene, activated carbon, micro and mesoporous carbon have been widely explored for energy storage. Alongside, fullerenes is a prominent class of materials that have recently garnered a huge interest in this field owing to their remarkable properties such as the unique arrangement of the carbon atoms in a buckyball configuration and ease of functionalization on the surface. However, fullerenes suffer from drawbacks including low performance, poor textural properties, disordered structure, and complicated synthesis due to lack of their solubility in various solvents. This creates a need for research on addressing these issues which will help to create a platform for the fabrication and the use of fullerenes in energy storage applications. Furthermore, one of the compelling issues with energy storage is the cost of the electrode materials. This thesis addresses these challenges through the fabrication of novel nanostructured mesoporous carbon/C60 hybrids with relatively easier synthesis route, high surface area, tunable pore width, and ordered morphology, by employing the hard-templating strategy in which silica source is used as a sacrificial template and sucrose is used as a low cost carbon precursor. It is expected that a combination of unique characteristics of fullerenes and mesoporous carbon would not only alleviate the energy storage performance as compared to other materials but also reduces the overall cost for the fabrication of the materials. To initiate the above research, it is highly imperative to review the recent developments in the field of nanostructured fullerenes for energy storage. The thesis begins with the first chapter which contains a comprehensive review covering the recent developments in the synthesis, and applications of nanostructured fullerenes. Several synthesis approaches such as precipitation, templating, polymerisation, evaporation, and hydrothermal methods have been discussed in details and relevant comparison provided, wherever necessary. Insights into the relationship between material structure and properties are included for better understanding of underlying principles. The application potential of nanostructured fullerenes such as energy storage and conversion, catalysis, adsorption and sensing are explained thoroughly. The last part of the review discusses the conclusions and the future directions that could be implemented for enhancing the prospect of nanostructured fullerenes for various application including energy storage and conversion. Chapter 2 specifically discusses the design and synthesis of two dimensional mesoporous C60/ carbon hybrids by using SBA-15 silica as a template and their applications in lithium ion battery and supercapacitors. A series of hybrid materials with different properties are prepared using sucrose as a source of carbon and C60 in a hard templating approach. The structural and textural properties are studied using characterisation techniques such as XRD, nitrogen adsorption, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and NEXAFS. The synthesized materials possess highly ordered porous structure which is confirmed through XRD and TEM investigations. The two dimensional mesoporous structure of the 2D SBA-15 template is replicated into ordered mesoporous carbon/C60. These materials show excellent textural properties with the large specific surface areas ranging from 563 to 808 m2/g. The electrochemical properties of these materials are analysed by using cyclic voltammetry, impedance and charge-discharge cycles. A specific capacitance of 213 F/g at 0.5 A/g is observed for the optimized sample MC60@C-1.33 which is much better than that of activated carbon and CNTs. Furthermore, the optimized material also performs very well for the lithium ion storage and yields an excellent specific capacity of 1299 mAh/g at 0.1 A/g. This study demonstrates the potential of such hybrids as versatile materials for energy storage in both supercapacitors and batteries. The pore structure of materials can be varied using different silica templates. In contrast to the previous study described in chapter 2, the current approach involved the replacement of SBA-15 with KIT-6 which generated materials with entirely different prospects in terms of structure and properties. The current chapter 3 describes the synthesis of 3D mesoporous C60/carbon hybrids using KIT-6 as a silica template and their applications for lithium ion battery and supercapacitor. The structural and textural properties are studied using sophisticated characterisation techniques such as XRD, nitrogen adsorption, SEM, TEM, and XPS. It is found that the nanocasting of the 3D template with well-ordered porous structure is successful which is confirmed with the XRD and HR-TEM measurements. By varying the amount of sucrose (carbon source), high surface area and high structural order are obtained by dense packing of carbon and fullerene layers. The optimized sample, MC60@C-1-K shows a high surface area of 988 m2/g, a large pore diameter (2.65 nm) and a large pore volume (1.28 cm3/g). The optimized material is tested for energy storage and displays a large specific capacitance of 254 F/g at 0.5 A/g and a high specific capacity of 1067 mAh/g for the lithium ion batteries. The thesis concludes by providing a summary of the contents of each chapter future directions in the research field of nanostructures fullerenes and their applications including energy storage, catalysis, CO2 capture and fuel cells.
- Subject
- mesoporous; fullerene; energy storage; supercapacitor; Li-ion battery
- Identifier
- http://hdl.handle.net/1959.13/1421612
- Identifier
- uon:37750
- Rights
- Copyright 2020 Arun Vijay Baskar
- Language
- eng
- Full Text
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