Type
Text
Type
Dissertation
Advisor
Grey, Clare P | Hsiao, Benjamin | White, Michael | Khalifah, Peter G | Doeff, Marca.
Date
2014-12-01
Keywords
Rechargeable batteries, Transition meta borates | Chemistry
Department
Department of Chemistry.
Language
en_US
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/77091
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
High-capacity rechargeable batteries play a central role in a variety of emerging technologies, including mobile electronics, plug-in and hybrid electric vehicles, and grid-scale storage. All of these technologies will greatly benefit from the design and discovery of next-generation cathode materials that can deliver substantially higher energy densities at reduced cost. Transition metal borates are promising cathode candidates for battery applications, since the mass/charge ratio (m/z) of borate group (BO33-) is the lowest among all common polyanion groups. A variety of borate based compounds were therefore explored as potential Li-ion and Mg-ion battery cathodes in this dissertation Comprehensive studies were carried out to understand the complex structural transformation of LiFeBO3 during battery cycling. It is observed that two distinct oxidative processes can occur in LiFeBO3 under different conditions, resulting in either delithiation or degradation. The delithiated and degraded phases share essentially the same Fe-B-O framework as the pristine LiFeBO3 phase, and can both reversibly cycle Li, but they differ in the presence (or absence) of Li/Fe disorder. This subtle structural difference results in a much higher operation potential for the pristine phase (2.8 V) than the degraded phase (1.8 V). LiCoBO3, with the same structural framework was also studied. However, it is observed that LiCoBO3 could not be delithiated due to its extremely low conductivity. MgxFe2-xB2O5 (x = 2/3 and 4/3) and MgVBO4 were investigated for their potential applications as cathodes for Mg-ion batteries. It is observed that Mg/Fe and Mg/V disorder is responsible for the low degree of demagnesiation achieved for MgMB2O5 and MgVBO4 at room temperature. However, a large degree of demagnesiation was achieved when MgxFe2-xB2O5 was heated in air, suggesting the MgxFe2-xB2O5 structure could be demagnesiated if kinetic limitations are overcome. | 217 pages
Recommended Citation
Bo, Shou-Hang, "Transition metal borates as cathode materials for rechargeable batteries" (2014). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 2928.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/2928