The present Thesis concerns with the synthesis of novel functionalized 2D materials for applications as cathodes in lithium-ion batteries. It... Show moreThe present Thesis concerns with the synthesis of novel functionalized 2D materials for applications as cathodes in lithium-ion batteries. It further concerns with the role of porosity in these novel cathode materials to achieve simultaneously high energy and power density. Examples of the novel cathode materials synthesized here include several functionalized hexagonal boron nitride (hBN) and graphene (G) species. hBN was functionalized with Li₂C₂O₄, LiBF₄, -OBF₂ groups, NOBF₄, etc. The color of the functionalized hBN species ranges from white through brown to black indicating drastic changes in the band structure of hBN due to functionalization. Functionalized G species include Li₂C₂O₄ and -OBF₃ functionalized ones. Preliminary electrochemical tests were carried out for an initial assessment of the properties of these materials. Additionally, the role of the DOL solvent was also investigated in high power CFx batteries Show less
Motivated by the great performance of the graphene oxide battery and its poor safety, in the present work, an attempt is made to fabricate an... Show moreMotivated by the great performance of the graphene oxide battery and its poor safety, in the present work, an attempt is made to fabricate an alternative battery from functionalized 2-dimensional (2D) boron nitride. The expectation is that functionalized boron nitride can exhibit the same great electrochemical performance as graphene oxide while it would be much more thermally stable. Toward this goal, synthetic opportunities were explored to realize -OBF3 functionalized hexagonal boron nitride. Both top-down and bottom-up synthetic approaches were considered and implemented. In the top-down methods, commercially available bulk hexagonal boron nitride (h-BN) is reacted with functionalization agents such as LiOBF3 and LiOH.BF3. Synthesis of these functionalization agents and their reactions with h-BN were carried out in several different ways. Bottom-up synthetic approach using Boric Acid and Urea was utilized to synthesize turbostratic boron nitride (t-BN), which is an intermedier in the commercial synthesis of hexagonal boron nitride. Turbostratic boron nitride contains exfoliated and -OH functionalized monolayers of boron nitride. An attempt is made to esterify the -OH groups of turbostratic boron nitride to obtain the desired -OBF3 functionalized monolayers of h-BN. Initial electrochemical tests on turbostratic boron nitride and its esterified form are carried out along with ionic conductivity measurements. Only a very limited electrochemical activity was observed due to a low degree of functionalization in these materials, indicating the need for improved synthetic procedures to achieve the desired target materials. Show less
