Engineering Commons^™

Surface Modification Of Electrode Materials For Lithium-Ion Batteries, Biwei Xiao

Electronic Thesis and Dissertation Repository

The development of lithium-ion batteries (LIBs) has been hampered by the intrinsic limitations of the electrode materials. High-performance LIBs demand electrode materials with fast lithium/electron diffusion rate, stable surface chemistry and high specific capacity. Surface modification by atomic layer deposition (ALD) is an essential method to optimize the performance of the electrode materials. The research in this thesis aims at achieving high-performance LIBs via surface modification and understanding the mechanisms via synchrotron radiation.

Firstly, by applying ALD FePO₄ on LiNi_0.5Mn_1.5O₄ (LNMO), we successfully alleviated the electrolyte decomposition under high voltage by using the electrochemically …

Doping Plasmon-Enhanced Tio2 With Zirconia To Improve Solar Energy Harvesting In Dye-Sensitized Solar Cells, Anastasia Pasche

Electronic Thesis and Dissertation Repository

Solar energy is a promising solution towards meeting the world’s ever-growing energy demand. Dye-sensitized solar cells (DSSCs) are hybrid organic-inorganic solar cells with potential for commercial application, but are plagued by inefficiency due to their poor sunlight absorption. Silver nanoparticles have been shown to enhance the absorptive properties of DSSCs, but their plasmonic resonance causes local hot spots, resulting in cell deterioration. This thesis studies the mitigation of thermal energy loss of plasmon-enhanced DSSCs by the co-incorporation of zirconia, a well-known thermostabilizer, into the cell’s photoactive material. TiO2 was also synthesized using green bio-sourced solvents in supercritical CO2 to compare …

On Developing Novel Energy-Relates Nanostructured Materials By Atomic Layer Deposition, Xiangbo Meng

Electronic Thesis and Dissertation Repository

ABSTRACT

This thesis presents the fabrication of a series of novel nanostructured materials using atomic layer deposition (ALD). In contrast to traditional methods including chemical vapor deposition (CVD), physical vapor deposition (PVD), and solution-based processes, ALD benefits the synthesis processes of nanostructures with many unrivalled advantages such as atomic-scale control, low temperature, excellent uniformity and conformality. Depending on the employed precursors, substrates, and temperatures, the ALD processes exhibited different characteristics. In particular, ALD has capabilities in fine-tuning compositions and structural phases. In return, the synthesis and the resultant nanostructured materials show many novelties.

This thesis covers ALD processes of four …