Flame Combustion Synthesis of Nanomaterials for Application in Lithium-Ion Batteries and Supercapacitors

Lithium-ion (Li-ion) batteries have been widely applied as the energy source in portable electronic devices due to their high energy density in comparison to other battery technologies. In recent years, the increasing adoption of Li-ion batteries by the automotive industry has led to increased demand for higher rate handling performance that supports the fast acceleration of electric vehicles. Hence, it is essential to improve the sluggish kinetics of Li+ diffusion in the solid state. One of the most effective strategies is to engineer nanostructured electrodes, which typically have high specific surface areas to shorten the diffusion pathways of ions and electrons during electrochemical reactions. Additionally, there has been tremendous research interest in supercapacitors since they bridge the gap between Li-ion batteries and dielectric capacitors. Nanostructured metal oxides hold great potential as replacements for commercial activated carbons as high-performance electrode materials. However, the complex processing steps and the difficulty in scaling up established wet chemistry manufacturing routes for the nanostructured materials present significant challenges to their application in commercial Li-ion batteries and supercapacitors. Reactive spray deposition technology (RSDT), a flame combustion synthetic method in the open atmosphere, offers a promising alternative that simplifies and lowers the cost of the nanostructured electrode fabrication process. It combines the synthesis and deposition of the electrochemically active nanomaterials onto the current collectors into a single-step process. Its operation is continuous and scalable, making it suitable for industrial manufacturing. Yang Wang – University of Connecticut, [2018] This thesis work focused on the synthesis and the electrochemical investigation of nanostructured electrodes fabricated by RSDT. The process-structure relationship of the electrodes was investigated and the effects of physical characteristics of the as-prepared electrodes on their electrochemical properties were systematically studied. The first part of this dissertation focuses on the development of nanostructured LiNi0.8Co0.2O2, LiNi1/3Mn1/3Co1/3O2 and α-Fe2O3 electrodes for application in Li-ion batteries. The second part of this dissertation explores the fabrication of binder-free three-dimensional Co3O4 electrodes for application in supercapacitors. Furthermore, the effects of different conductive additives on the electrochemical performance of the supercapacitors were investigated