Abstract
The applications of rechargeable batteries can be generally categorised into two main groups. The first would be in the storage of energy in the energy grid system where it is applied after renewable energy has been harvested. The next area where rechargeable batteries are widely used are in portable devices. With the boom in portable devices, the demand for rechargeable batteries that have high energy densities and excellent rate capabilities has exponentially increased. Researchers have made use nanomaterials and materials engineering to synthesis materials in the nanoscale, greatly increasing the surface area of the active ions storage sites. However, the performance are still lacking in terms of rate cycling and cycle life. Therefore, by researching into 3D porous structures and employing them in energy storage devices, we used a two pronged approach to tackle the issue of improving energy densities in energy storage devices and the safety of the application of these devices. As we dig deeper in the chemistries encompassing reactions in sodium ion batteries, we explore the application of nanomaterials (MoS2 and SnS2) which are grown on substrates (3D graphene and Prussian Blue) using CVD and hydrothermal methods. After we have achieved a better understanding in the reaction kinetics and the physical and chemical reactions, we developed a material which can be 3D printed and applied in flexible energy storage devices. As we are geared towards improving the energy densities and safety of energy storage devices, we developed Fe2O3 on reduced graphene oxide, which is made into a slurry and 3D printed to be used directly as an electrode in lithium ion batteries. The end of this thesis also shows the future work where we developed materials which can be used in flexible electronics. The contributions of the works presented in this thesis includes 3 Journals, 4 posters and 1 patent.