Advanced search options

Advanced Search Options 🞨

Browse by author name (“Author name starts with…”).

Find ETDs with:

in
/  
in
/  
in
/  
in

Written in Published in Earliest date Latest date

Sorted by

Results per page:

Sorted by: relevance · author · university · dateNew search

You searched for +publisher:"Clemson University" +contributor:("Kyle Brinkman"). Showing records 1 – 3 of 3 total matches.

Search Limiters

Last 2 Years | English Only

No search limiters apply to these results.

▼ Search Limiters


Clemson University

1. Bolek, Katherine. The Effect of Excess Lithium on the Phase Formation, Structure and Electrical Properties of LLZO Garnet Structured Solid-State Electrolyte.

Degree: MS, School of Materials Science and Engineering, 2020, Clemson University

Solid-state lithium ion batteries are currently at the forefront of investigations to replace conventional lithium ion batteries in order to improve overall safety and device performance. Researchers have investigated many substitutes to organic based conventional liquid electrolytes that result in high levels of Li ion conductivity. Cubic Li7La3Zr2O12 (LLZO) is a leader among solid-state electrolyte research. Unfortunately, pure LLZO at room temperature is generally a tetragonal structure that is significantly less conductive than cubic LLZO. This research uses a gallium dopant to reach the highly conductive cubic LLZO structure. However, a dopant is not enough to ensure a highly conductive LLZO sample. Lithium evaporates during the calcining and sintering stages of sample preparation. In order to reach an actual composition close to the targeted composition, additional lithium must be added, or lithium loss must be prevented. The goal of this research is to investigate the best methods and amounts of excess lithium to add in order to obtain a composition as close as possible to the targeted compositions. The most common method in literature to combat lithium loss is the addition of an excess lithium precursor to the initial set of precursors. This research studied the effect of excess Li2CO3 precursors in LLZO at zero, ten, twenty, and thirty weight percent excess. Another method studied in this research to prevent lithium loss was using a boating technique with excess lithium carbonate. Half a gram of lithium carbonate was placed on the edges of the sintering crucible, while the sample pellets were in the middle of the crucible untouched by the excess powder. The lithium carbonate powder evaporated during sintering resulting in a build-up of lithium vapor pressure in the crucible which will aid in lithium retention as it is more difficult to evaporate in high vapor pressure conditions. This research found that gallium doped LLZO (Ga0.5Li5.5La3Zr2O12) with ten weight percent excess Li2CO3 precursor along with the boating technique resulted in the highest density and highest conductivity of all samples tested. While more testing needs to be done on this research, the data shows how important lithium content is to produce a highly conductive solid electrolyte. Advisors/Committee Members: Kyle Brinkman, Ming Tang, Jianhua Tong.

Subjects/Keywords: electrolyte; excess lithium; garnet; LLZO

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Bolek, K. (2020). The Effect of Excess Lithium on the Phase Formation, Structure and Electrical Properties of LLZO Garnet Structured Solid-State Electrolyte. (Masters Thesis). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_theses/3405

Chicago Manual of Style (16th Edition):

Bolek, Katherine. “The Effect of Excess Lithium on the Phase Formation, Structure and Electrical Properties of LLZO Garnet Structured Solid-State Electrolyte.” 2020. Masters Thesis, Clemson University. Accessed December 05, 2020. https://tigerprints.clemson.edu/all_theses/3405.

MLA Handbook (7th Edition):

Bolek, Katherine. “The Effect of Excess Lithium on the Phase Formation, Structure and Electrical Properties of LLZO Garnet Structured Solid-State Electrolyte.” 2020. Web. 05 Dec 2020.

Vancouver:

Bolek K. The Effect of Excess Lithium on the Phase Formation, Structure and Electrical Properties of LLZO Garnet Structured Solid-State Electrolyte. [Internet] [Masters thesis]. Clemson University; 2020. [cited 2020 Dec 05]. Available from: https://tigerprints.clemson.edu/all_theses/3405.

Council of Science Editors:

Bolek K. The Effect of Excess Lithium on the Phase Formation, Structure and Electrical Properties of LLZO Garnet Structured Solid-State Electrolyte. [Masters Thesis]. Clemson University; 2020. Available from: https://tigerprints.clemson.edu/all_theses/3405


Clemson University

2. Azami Ghadkolai, Milad. Engineered Porous Electrodes for High Performance Li-Ion Batteries.

Degree: PhD, School of Materials Science and Engineering, 2020, Clemson University

High specific energy/power is nearly always desirable in battery systems but it is especially important in batteries for electric vehicles. One approach for increasing the specific energy/power is to maximize the mass fraction of active materials. A straight forward approach to realize this is to make the electrodes as thick as possible. There are two main limitations for increasing electrode thickness. One is the need for active material with high electronic and ionic transport properties, and the other is rapid Li ion transport through the entire thickness of a porous electrode. In the research described in this dissertation, lithium titanite (Li4Ti5O12, LTO) was chosen as a promising safe active material for lithium batteries. In spite of many advantages, this material suffers from low electronic and ionic conductivity, making it an unsuitable choice for manufacturing thick electrodes. In order to alleviate this problem, a thorough investigation of the effect of Mo doping on structure, electronic and ionic conductivity of LTO was conducted. In order to facilitate rapid Li ion transport through the thickness of thick porous electrodes, a novel processing approach, freeze tape casting, was developed to make ordered anisotropic macro porous electrodes directly on the surface of a metal foil current collector. The effect of electrode processing parameters, microstructure and thickness on the electrochemical performance of the electrode was studied experimentally. Finally, comprehensive numerically simulations were conducted to investigate the effect of electrode microstructure (specifically thickness and tortuosity) on Li-ion transport at different discharge rate (C-rate) for both normal and freeze tape cast electrodes in order to guide the design of optimal microstructure. Computer simulations show that freeze tape cast electrodes may be fully discharged up to 750 µm thickness at 1 C rate compared to 300 µm for normal tape cast electrodes with the same mass loading. Freeze tape cast electrodes also show stable maximum areal capacity for C rates about double the maximum C rates of their normal tape cast electrode counterparts with the same mass loading. Advisors/Committee Members: Rajendra K Bordia, Stephen Creager, Kyle Brinkman, Jianhua Tong, Ulf Schiller.

Subjects/Keywords: Battery simulation; Electronic/ionic conductivity; Freeze tape casting; Li-ion battery; Lithium Titanate; Microstructure design

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Azami Ghadkolai, M. (2020). Engineered Porous Electrodes for High Performance Li-Ion Batteries. (Doctoral Dissertation). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_dissertations/2623

Chicago Manual of Style (16th Edition):

Azami Ghadkolai, Milad. “Engineered Porous Electrodes for High Performance Li-Ion Batteries.” 2020. Doctoral Dissertation, Clemson University. Accessed December 05, 2020. https://tigerprints.clemson.edu/all_dissertations/2623.

MLA Handbook (7th Edition):

Azami Ghadkolai, Milad. “Engineered Porous Electrodes for High Performance Li-Ion Batteries.” 2020. Web. 05 Dec 2020.

Vancouver:

Azami Ghadkolai M. Engineered Porous Electrodes for High Performance Li-Ion Batteries. [Internet] [Doctoral dissertation]. Clemson University; 2020. [cited 2020 Dec 05]. Available from: https://tigerprints.clemson.edu/all_dissertations/2623.

Council of Science Editors:

Azami Ghadkolai M. Engineered Porous Electrodes for High Performance Li-Ion Batteries. [Doctoral Dissertation]. Clemson University; 2020. Available from: https://tigerprints.clemson.edu/all_dissertations/2623


Clemson University

3. Grote, Robert L. The Effect of Composition on the Structure Symmetry and Stability of Tunnel-Structured Hollandite Ceramics for Nuclear Waste Immobilization.

Degree: PhD, School of Materials Science and Engineering, 2018, Clemson University

The ceramic phase hollandite is a component material for some multi-phase ceramic waste forms and has been a prominent ceramic waste form for the immobilization of cesium and strontium radionuclides. The immobilization of cesium is difficult due to its large size and water solubility. This dissertation is focused on understanding the fundamental structure of hollandite and the effect cesium doping has on the properties of hollandite in order to develop a more effective and efficient waste form for cesium immobilization. The topics cover the structure and stability, thermodynamic properties and phase formation, irradiation resistance, and leaching resistance of hollandite. A brief history, the current status, and advantages and shortcomings of hollandite as a waste form are given in the introduction and background chapter. In chapter 2, the effect of elemental doping on the hollandite structure, symmetry, and stability are described, and methods to improve these properties are presented. Different B-site dopants were tested to probe the monoclinic/tetragonal symmetry boundary of hollandite. Additionally, cesium doping into barium-zinc-titanium hollandite was performed to develop a better understanding of how divalent cations affect the stability of hollandite and how cesium doping and occupancy can be controlled to increase the stability of hollandite. In chapter 3, the thermal properties were studied and calorimetry was performed. The melting, thermal stability, and cesium loss behaviors were measured and found to be dependent on the cesium content. Calorimetry data was collected for a series of cesium doped hollandite. The drop solution enthalpy was measured and the formation enthalpy was calculated. Zinc hollandite formation was more favorable and energetic stability increased as the cesium content increased. In chapter 4, the radiation stability of hollandite was measured over a full range of cesium doping. The onset of amorphization did not vary with cesium content; however, the dose required for full amorphization doubled with full cesium substitution. Amorphization was also measured at an elevated temperature, and the critical amorphization temperature of hollandite was measured between 200 °C and 300 °C. A defect mechanism was proposed, and the amorphization model for hollandite was determined. In chapter 5, elemental leaching dependence on cesium content was studied. The amorphization mechanism and effect of irradiation on leaching rate were discussed. The leaching rate decreased with increasing cesium content. Leaching experiments were also performed on irradiation samples. Cesium leaching was found to increase after irradiation with the high cesium content intermediate compositions exhibited the lowest cesium losses. In summary, the stability of zinc hollandite was measured and found to be primarily dependent on cesium content with some occupancy effect. Cesium doping increased the stability of the tetragonal symmetry, reduced cesium loss during processing and leaching, stabilized hollandite formation,… Advisors/Committee Members: Kyle Brinkman, Committee Chair, Ranjendra Bordia, Fei Peng, Lindsay Shuller-Nickles.

Subjects/Keywords: Calorimetry; Ceramic; Cesium; Hollandite; Radiation Stability; Waste forms

Record DetailsSimilar RecordsGoogle PlusoneFacebookTwitterCiteULikeMendeleyreddit

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Grote, R. L. (2018). The Effect of Composition on the Structure Symmetry and Stability of Tunnel-Structured Hollandite Ceramics for Nuclear Waste Immobilization. (Doctoral Dissertation). Clemson University. Retrieved from https://tigerprints.clemson.edu/all_dissertations/2248

Chicago Manual of Style (16th Edition):

Grote, Robert L. “The Effect of Composition on the Structure Symmetry and Stability of Tunnel-Structured Hollandite Ceramics for Nuclear Waste Immobilization.” 2018. Doctoral Dissertation, Clemson University. Accessed December 05, 2020. https://tigerprints.clemson.edu/all_dissertations/2248.

MLA Handbook (7th Edition):

Grote, Robert L. “The Effect of Composition on the Structure Symmetry and Stability of Tunnel-Structured Hollandite Ceramics for Nuclear Waste Immobilization.” 2018. Web. 05 Dec 2020.

Vancouver:

Grote RL. The Effect of Composition on the Structure Symmetry and Stability of Tunnel-Structured Hollandite Ceramics for Nuclear Waste Immobilization. [Internet] [Doctoral dissertation]. Clemson University; 2018. [cited 2020 Dec 05]. Available from: https://tigerprints.clemson.edu/all_dissertations/2248.

Council of Science Editors:

Grote RL. The Effect of Composition on the Structure Symmetry and Stability of Tunnel-Structured Hollandite Ceramics for Nuclear Waste Immobilization. [Doctoral Dissertation]. Clemson University; 2018. Available from: https://tigerprints.clemson.edu/all_dissertations/2248

.