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Lithium-ion batteries are one of the most widely used energy storage solutions today. As renewable energy sources proliferate to meet growth in worldwide energy consumption, it is important that lithium-ion batteries be improved to help capture this energy for use when the demand arises. One way to boost the performance

Lithium-ion batteries are one of the most widely used energy storage solutions today. As renewable energy sources proliferate to meet growth in worldwide energy consumption, it is important that lithium-ion batteries be improved to help capture this energy for use when the demand arises. One way to boost the performance of lithium-ion batteries is to replace the electrode active materials with materials of higher specific capacity. Silicon is one material that has been widely touted as a potential replacement for the graphite used in commercial anodes with a theoretical capacity of 3500 mAh/g as opposed to graphite's 372 mAh/g. However, bulk silicon is known to pulverize after experiencing large strains during lithiation. Here, silicon clathrates are investigated as a potential structure for accommodation of these strains. Silicon clathrates consist of covalently bonded silicon host cages surrounding a guest alkali or alkaline earth metal ion. Previous work has looked at silicon clathrates for their superconducting and thermoelectric properties. In this study, electrochemical properties of type I and II silicon clathrates with sodium guest ions (NaxSi46 and NaxSi136) and type I silicon clathrates with copper framework substitution and barium guest ions (Ba8CuxSi46-x) are examined. Sodium clathrates showed very high capacities during initial lithiation (>2500 mAh/g), but rapidly lost capacity thereafter. X-ray diffraction after lithiation showed conversion of the clathrate phase to lithium silicide and then to amorphous silicon after delithiation, indicating destruction of the clathrate structure as a possible explanation for the rapid capacity fade. Ba8CuxSi46-x clathrates were found to have their structures completely intact after 50 cycles. However, they had very low reversible capacities (<100 mAh/g) and potentially might not be electrochemically active. Further work is needed to better understand exactly how lithium is inserted into clathrates and if copper impurities detected during wavelength-dispersive X-ray spectroscopy could be inhibiting lithium transport into the clathrates.
ContributorsWagner, Nicholas Adam (Author) / Chan, Candace (Thesis director) / Sieradzki, Karl (Committee member) / Barrett, The Honors College (Contributor) / Materials Science and Engineering Program (Contributor)
Created2014-05
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Stress for college students is nothing new and as more kids go to college the number of cases are on the rise. This issue is apparent at colleges across the nation including Arizona State University. StreetWise aims to help students prevent or appropriately deal with stress through interactive lessons teaching

Stress for college students is nothing new and as more kids go to college the number of cases are on the rise. This issue is apparent at colleges across the nation including Arizona State University. StreetWise aims to help students prevent or appropriately deal with stress through interactive lessons teaching students life skills, social skills, and emotional intelligence.<br/>In order to prove the value of our service, StreetWise conducted a survey that asked students about their habits, thoughts on stress, and their future. Students from Arizona State University were surveyed with questions on respondent background, employment, number one stressor, preferred learning method, and topics that students were interested in learning. We found that students’ number one stressor was school but was interested in learning skills that would prepare them for their future after graduation. We used the results to make final decisions so that StreetWise could offer lessons that students would get the most value out of. This led to us conducting a second survey which included mock ups of the website, examples of interactive lesson plans, and an overview of the app. Students from the first survey were surveyed in addition to new respondents. This survey was intended for us to ensure that our service would maintain its value to students with the aesthetic and interface that we envisioned.

ContributorsWard, William Henry (Co-author) / Ahir, Hiral (Co-author) / Compton, Katherine (Co-author) / Byrne, Jared (Thesis director) / Hall, Rick (Committee member) / Materials Science and Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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Description

Stress for college students is nothing new and as more kids go to college the number of cases are on the rise. This issue is apparent at colleges across the nation including Arizona State University. StreetWise aims to help students prevent or appropriately deal with stress through interactive lessons teaching

Stress for college students is nothing new and as more kids go to college the number of cases are on the rise. This issue is apparent at colleges across the nation including Arizona State University. StreetWise aims to help students prevent or appropriately deal with stress through interactive lessons teaching students life skills, social skills, and emotional intelligence.<br/>In order to prove the value of our service, StreetWise conducted a survey that asked students about their habits, thoughts on stress, and their future. Students from Arizona State University were surveyed with questions on respondent background, employment, number one stressor, preferred learning method, and topics that students were interested in learning. We found that students’ number one stressor was school but was interested in learning skills that would prepare them for their future after graduation. We used the results to make final decisions so that StreetWise could offer lessons that students would get the most value out of. This led to us conducting a second survey which included mock ups of the website, examples of interactive lesson plans, and an overview of the app. Students from the first survey were surveyed in addition to new respondents. This survey was intended for us to ensure that our service would maintain its value to students with the aesthetic and interface that we envisioned.

ContributorsCompton, Katherine May (Co-author) / Ahir, Hiral (Co-author) / Ward, William (Co-author) / Byrne, Jared (Thesis director) / Hall, Rick (Committee member) / Dean, W.P. Carey School of Business (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
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Description

Stress for college students is nothing new and as more kids go to college the number of cases are on the rise. This issue is apparent at colleges across the nation including Arizona State University. StreetWise aims to help students prevent or appropriately deal with stress through interactive lessons teaching

Stress for college students is nothing new and as more kids go to college the number of cases are on the rise. This issue is apparent at colleges across the nation including Arizona State University. StreetWise aims to help students prevent or appropriately deal with stress through interactive lessons teaching students life skills, social skills, and emotional intelligence.<br/>In order to prove the value of our service, StreetWise conducted a survey that asked students about their habits, thoughts on stress, and their future. Students from Arizona State University were surveyed with questions on respondent background, employment, number one stressor, preferred learning method, and topics that students were interested in learning. We found that students’ number one stressor was school but was interested in learning skills that would prepare them for their future after graduation. We used the results to make final decisions so that StreetWise could offer lessons that students would get the most value out of. This led to us conducting a second survey which included mock ups of the website, examples of interactive lesson plans, and an overview of the app. Students from the first survey were surveyed in addition to new respondents. This survey was intended for us to ensure that our service would maintain its value to students with the aesthetic and interface that we envisioned.

ContributorsAhir, Hiral V (Co-author) / Compton, Katherine (Co-author) / Ward, William (Co-author) / Byrne, Jared (Thesis director) / Hall, Rick (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description

Sun Stop Solar, is a solar module development and manufacturing company that utilizes a unique class of materials, perovskites, as the solar cells’ absorption layer. Perovskites are a unique class of compounds with some perovskites being able to absorb photons and excite electrons to create current. Sun Stop Solar plans

Sun Stop Solar, is a solar module development and manufacturing company that utilizes a unique class of materials, perovskites, as the solar cells’ absorption layer. Perovskites are a unique class of compounds with some perovskites being able to absorb photons and excite electrons to create current. Sun Stop Solar plans to initially begin by developing the foundational technological patent for our perovskite-based single-junction solar cells. Sun Stop Solar plans to initially begin by first having a patent set up, then licensing our patent to a manufacturer, and slowly building towards manufacturing our own solar modules.

ContributorsMatyushov, Ivan (Author) / Aboudi, Joseph (Co-author) / Hofer, David (Co-author) / Byrne, Jared (Thesis director) / Lawson, Brennan (Committee member) / Cartwright, Bryce (Committee member) / Adarsh, Siddharth (Committee member) / Higashino, Katsuko (Committee member) / Barrett, The Honors College (Contributor) / Materials Science and Engineering Program (Contributor)
Created2023-05
Description

With the rise of global warming and the growing energy crisis, scientists have pivoted from typical resources to look for new materials and technologies that can aid in advancing renewable energy efforts. Perovskite materials hold the potential for making high-efficiency, low-cost solar cells through solution processing of Earth abundant materials;

With the rise of global warming and the growing energy crisis, scientists have pivoted from typical resources to look for new materials and technologies that can aid in advancing renewable energy efforts. Perovskite materials hold the potential for making high-efficiency, low-cost solar cells through solution processing of Earth abundant materials; however, scalability and manufacturability remain a challenge. In order to transition from small scale processing in inert environments via spin coating to higher throughput processing in ambient conditions via blade coating, the fundamentals of perovskite crystallization must be understood. Classical nucleation theory, the LaMer relation, and nonclassical crystallization considerations are discussed to provide a mechanism by which gellan gum, a nontoxic biopolymer from the food industry, has enabled quality halide perovskite thin films. Specifically, this research aims to study the effects of gellan gum in improving perovskite manufacturability by controlling crystallization through indirect alteration of evaporation and supersaturation rates by modifying fluid dynamics and the free energy associated with nucleation and growth. Simply, gellan gum controls crystallization to enable the fabrication of promising scalable PVSK devices in open air.

ContributorsCartledge, Carsen (Author) / Rolston, Nicholas (Thesis director) / Yu, Zhengshan (Committee member) / Barrett, The Honors College (Contributor) / Materials Science and Engineering Program (Contributor) / School of International Letters and Cultures (Contributor) / School of Art (Contributor)
Created2023-05
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Description
The investigation into wide band gap semiconductors for use in tandem solar cells has become an increasingly more researched area with many new absorbers outlining the landscape. Pairing silicon with another cheap wide band gap semiconductor absorber can generate more efficient solar cell, which could continue to drive up the

The investigation into wide band gap semiconductors for use in tandem solar cells has become an increasingly more researched area with many new absorbers outlining the landscape. Pairing silicon with another cheap wide band gap semiconductor absorber can generate more efficient solar cell, which could continue to drive up the energy output from solar. One such recently researched wide band gap absorber is ZnSnN2. ZnSnN2 proves too difficult to form under most conditions, but has the necessary band gap to make it a potential earth abundant solar absorber. The deposition process for ZnSnN2 is usually conducted with Zn and Sn metal targets while flowing N2 gas. Due to restrictions with chamber depositions, instead ZnO and SnO2 targets were sputtered with N2 gas to attempt to form separate zinc and tin oxynitrides as an initial single target study prior to future combinatorial studies. The electrical and optical properties and crystal structure of these thin films were analyzed to determine the nitrogen incorporation in the thin films through X-ray diffraction, UV-Vis spectrophotometry, and 4-point probe measurements. The SnO2 thin films showed a clear response in the absorption coefficient leading but showed no observable XRD peak shift. Thus, it is unlikely that substantial amounts of nitrogen were incorporated into SnO¬2. ZnO showed a clear response increase in conductivity with N2 with an additional shift in the XRD peak at 300 °C and potential secondary phase peak. Nitrogen incorporation was achieved with fair amounts of certainty for the ZnO thin films.
ContributorsTheut, Nicholas C (Author) / Bertoni, Mariana (Thesis director) / Holman, Zachary (Committee member) / Materials Science and Engineering Program (Contributor) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
With renewable energy on the rise, researchers have turned their funding and their focus towards new solar cell technologies, and perovskites are a major source of interest. This class of materials is particularly interesting due to their quick, simple synthesis as well as their physical and electrical superiority when compared

With renewable energy on the rise, researchers have turned their funding and their focus towards new solar cell technologies, and perovskites are a major source of interest. This class of materials is particularly interesting due to their quick, simple synthesis as well as their physical and electrical superiority when compared to current silicon-based solar cells. Through this thesis, we will explore the synthesis of various types of perovskites and their subsequent characterization, which includes optical microscopy, photoluminescence spectroscopy, Raman microscopy, and X-ray diffraction. Analyzing two different perovskites both before and after a two-week period of storage revealed that while synthesis is indeed experiment-friendly, these materials have a concerning lack of stability even in ideal conditions.
ContributorsBuzas, Benjamin Joseph (Author) / Tongay, Sefaattin (Thesis director) / Muhich, Christopher (Committee member) / Materials Science and Engineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
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Description
Heavy metals such as selenium can be especially important to limit because they can cause serious health problems even at relatively low concentrations. In an effort to selectively remove selenium from solution, a PAABA (poly(aniline-co-p-aminobenzoic acid) conductive copolymer was synthesized in a selenic acid solution, and its ability to remove

Heavy metals such as selenium can be especially important to limit because they can cause serious health problems even at relatively low concentrations. In an effort to selectively remove selenium from solution, a PAABA (poly(aniline-co-p-aminobenzoic acid) conductive copolymer was synthesized in a selenic acid solution, and its ability to remove selenium was studied. Analysis of the Raman spectra confirmed the hypothesized formation of PAABA polymer. Constant voltage cycles showed success in precipitating the selenium out of solution via electroreduction, and ICP-MS confirmed the reduction of selenium concentrated in solution. These results indicate the PAABA synthesized in selenic acid shows promise for selective water treatment.
ContributorsSulzman, Serita Lynne (Author) / Wang, Qing Hua (Thesis director) / Chan, Candace (Committee member) / Materials Science and Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
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Description
In this research, the effect of the crystal structure of the parent phase on the morphology of nanoporous gold is explored. Specifically, Cu-Au alloys are studied. For this experiment, Cu0.75Au0.25 is heat treated to achieve an ordered phase Cu3Au and a disordered random solid solution, face centered cubic, Cu0.75Au0.25 phase,

In this research, the effect of the crystal structure of the parent phase on the morphology of nanoporous gold is explored. Specifically, Cu-Au alloys are studied. For this experiment, Cu0.75Au0.25 is heat treated to achieve an ordered phase Cu3Au and a disordered random solid solution, face centered cubic, Cu0.75Au0.25 phase, which are then dealloyed to form nanoporous gold (NPG). Using a morphology digital image analysis software called AQUAMI, SEM images of the NPG morphology were characterized to collect data on the ligament length, ligament diameter, porosity size, etc. of the samples. It was determined that the NPG formed from the ordered parent phase had an average ligament diameter that was 10 nm larger than the NPG formed from the disordered parent phase. This may be due to the ordered crystal structure allowing for faster gold diffusion and coarsening resulting in an increased average ligament size. Further future work is needed in order to obtain further evidence to support this hypothesis.
ContributorsTse, Ariana Yusof (Author) / Sieradzki, Karl (Thesis director) / Wang, Qing Hua (Committee member) / Materials Science and Engineering Program (Contributor) / Walter Cronkite School of Journalism & Mass Comm (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05