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- All Subjects: Battery
- Creators: Buttry, Daniel A
- Member of: Theses and Dissertations
- Status: Published
Description
A lack of adequate energy storage technologies is arguably the greatest hindrance to a modern sustainable energy infrastructure. Chemical energy storage, in the form of batteries, is an obvious solution to the problem. Unfortunately, today’s state of the art battery technologies fail to meet the desired metrics for full scale electric grid and/or electric vehicle role out. Considerable effort from scientists and engineers has gone into the pursuit of battery chemistries theoretically capable of far outperforming leading technologies like Li-ion cells. For instance, an anode of the relatively abundant and cheap metal, magnesium, would boost the specific energy by over 4.6 times that of the current Li-ion anode (LiC6).
The work presented here explores the compatibility of magnesium electrolytes in TFSI–-based ionic liquids with a Mg anode (TFSI = bis(trifluoromethylsulfonyl)imide). Correlations are made between the Mg2+ speciation conditions in bulk solutions (as determined via Raman spectroscopy) and the corresponding electrochemical behavior of the electrolytes. It was found that by creating specific chelating conditions, with an appropriate Mg salt, the desired electrochemical behavior could be obtained, i.e. reversible electrodeposition and dissolution. Removal of TFSI– contact ion pairs from the Mg2+ solvation shell was found to be essential for reversible electrodeposition. Ionic liquids with polyethylene glycol chains pendent from a parent pyrrolidinium cation were synthesized and used to create the necessary complexes with Mg2+, from Mg(BH4)2, so that reversible electrodeposition from a purely ionic liquid medium was achieved.
The following document discusses findings from several electrochemical experiments on magnesium electrolytes in ionic liquids. Explanations for the failure of many of these systems to produce reversible Mg electrodeposition are provided. The key characteristics of ionic liquid systems that are capable of achieving reversible Mg electrodeposition are also given.
The work presented here explores the compatibility of magnesium electrolytes in TFSI–-based ionic liquids with a Mg anode (TFSI = bis(trifluoromethylsulfonyl)imide). Correlations are made between the Mg2+ speciation conditions in bulk solutions (as determined via Raman spectroscopy) and the corresponding electrochemical behavior of the electrolytes. It was found that by creating specific chelating conditions, with an appropriate Mg salt, the desired electrochemical behavior could be obtained, i.e. reversible electrodeposition and dissolution. Removal of TFSI– contact ion pairs from the Mg2+ solvation shell was found to be essential for reversible electrodeposition. Ionic liquids with polyethylene glycol chains pendent from a parent pyrrolidinium cation were synthesized and used to create the necessary complexes with Mg2+, from Mg(BH4)2, so that reversible electrodeposition from a purely ionic liquid medium was achieved.
The following document discusses findings from several electrochemical experiments on magnesium electrolytes in ionic liquids. Explanations for the failure of many of these systems to produce reversible Mg electrodeposition are provided. The key characteristics of ionic liquid systems that are capable of achieving reversible Mg electrodeposition are also given.
ContributorsWatkins, Tylan Strike (Author) / Buttry, Daniel A (Thesis advisor) / Wolf, George (Committee member) / Williams, Peter (Committee member) / Arizona State University (Publisher)
Created2016
Description
Nanomaterials have attracted considerable attention in recent research due to their wide applications in various fields such as material science, physical science, electrical engineering, and biomedical engineering. Researchers have developed many methods for synthesizing different types of nanostructures and have further applied them in various applications. However, in many cases, a molecular level understanding of nanoparticles and their associated surface chemistry is lacking investigation. Understanding the surface chemistry of nanomaterials is of great significance for obtaining a better understanding of the properties and functions of the nanomaterials. Nuclear magnetic resonance (NMR) spectroscopy can provide a familiar means of looking at the molecular structure of molecules bound to surfaces of nanomaterials as well as a method to determine the size of nanoparticles in solution. Here, a combination of NMR spectroscopic techniques including one- and two-dimensional NMR spectroscopies was used to investigate the surface chemistry and physical properties of some common nanomaterials, including for example, thiol-protected gold nanostructures and biomolecule-capped silica nanoparticles.
Silk is a natural protein fiber that features unique properties such as excellent mechanical properties, biocompatibility, and non-linear optical properties. These appealing physical properties originate from the silk structure, and therefore, the structural analysis of silk is of great importance for revealing the mystery of these impressive properties and developing novel silk-based biomaterials as well. Here, solid-state NMR spectroscopy was used to elucidate the secondary structure of silk proteins in N. clavipes spider dragline silk and B. mori silkworm silk. It is found that the Gly-Gly-X (X=Leu, Tyr, Gln) motif in spider dragline silk is not in a β-sheet or α-helix structure and is very likely to be present in a disordered structure with evidence for 31-helix confirmation. In addition, the conformations of the Ala, Ser, and Tyr residues in silk fibroin of B. mori were investigated and it indicates that the Ala, Ser, and Tyr residues are all present in disordered structures in silk I (before spinning), while show different conformations in silk II (after spinning). Specifically, in silk II, the Ala and Tyr residues are present in both disordered structures and β-sheet structures, and the Ser residues are present primarily in β-sheet structures.
Silk is a natural protein fiber that features unique properties such as excellent mechanical properties, biocompatibility, and non-linear optical properties. These appealing physical properties originate from the silk structure, and therefore, the structural analysis of silk is of great importance for revealing the mystery of these impressive properties and developing novel silk-based biomaterials as well. Here, solid-state NMR spectroscopy was used to elucidate the secondary structure of silk proteins in N. clavipes spider dragline silk and B. mori silkworm silk. It is found that the Gly-Gly-X (X=Leu, Tyr, Gln) motif in spider dragline silk is not in a β-sheet or α-helix structure and is very likely to be present in a disordered structure with evidence for 31-helix confirmation. In addition, the conformations of the Ala, Ser, and Tyr residues in silk fibroin of B. mori were investigated and it indicates that the Ala, Ser, and Tyr residues are all present in disordered structures in silk I (before spinning), while show different conformations in silk II (after spinning). Specifically, in silk II, the Ala and Tyr residues are present in both disordered structures and β-sheet structures, and the Ser residues are present primarily in β-sheet structures.
ContributorsGuo, Chengchen (Author) / Yarger, Jeffery L (Thesis advisor) / Holland, Gregory P (Thesis advisor) / Buttry, Daniel A (Committee member) / Wang, Xu (Committee member) / Arizona State University (Publisher)
Created2017
Description
Lithium ion batteries are quintessential components of modern life. They are used to power smart devices — phones, tablets, laptops, and are rapidly becoming major elements in the automotive industry. Demand projections for lithium are skyrocketing with production struggling to keep up pace. This drive is due mostly to the rapid adoption of electric vehicles; sales of electric vehicles in 2020 are more than double what they were only a year prior. With such staggering growth it is important to understand how lithium is sourced and what that means for the environment. Will production even be capable of meeting the demand as more industries make use of this valuable element? How will the environmental impact of lithium affect growth? This thesis attempts to answer these questions as the world looks to a decade of rapid growth for lithium ion batteries.
ContributorsMelton, John (Author) / Brian, Jennifer (Thesis director) / Karwat, Darshawn (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05