Matching Items (3)
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- All Subjects: lithium-ion batteries
- Creators: Dai, Lenore
- Creators: Lin, Jerry Y. S.
Description
The two central goals of this project were 1) to develop a testing method utilizing coatings on ultra-thin stainless steel to measure the thermal conductivity (k) of battery electrode materials and composites, and 2) to measure and compare the thermal conductivities of lithium iron phosphate (LiFePO4, "LFP") in industry-standard graphite/LFP mixtures as well as graphene/LFP mixtures and a synthesized graphene/LFP nanocomposite. Graphene synthesis was attempted before purchasing graphene materials, and further exploration of graphene synthesis is recommended due to limitations in purchased product quality. While it was determined after extensive experimentation that the graphene/LFP nanocomposite could not be successfully synthesized according to current literature information, a mixed composite of graphene/LFP was successfully tested and found to have k = 0.23 W/m*K. This result provides a starting point for further thermal testing method development and k optimization in Li-ion battery electrode nanocomposites.
ContributorsStehlik, Daniel Wesley (Author) / Chan, Candace K. (Thesis director) / Dai, Lenore (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor)
Created2014-05
Description
Lithium ion batteries prepared with a ceramic separator, have proven to possess improved safety, reliability as well as performance characteristics when compared to those with polymer separators which are prone to thermal runaway. Purely inorganic separators are highly brittle and expensive. The electrode-supported ceramic separator permits thinner separators which are a lot more flexible in comparison. In this work, it was observed that not any α-alumina could be used by the blade coating process to get a good quality separator on Li4Ti5O12 (LTO) electrode. In this work specifically, the effect of particle size of α-alumina, on processability of slurry was investigated. The effect of the particle size variations on quality of separator formation was also studied. Most importantly, the effect of alumina particle size and its distribution on the performance of LTO/Li half cells is examined in detail. Large-sized particles were found to severely limit the ability to fabricate such separators. The α-alumina slurry was coated onto electrode substrate, leading to possible interaction between α-alumina and LTO substrate. The interaction between submicron sized particles of α-alumina with the substrate electrode pores, was found to affect the performance and the stability of the separator. Utilizing a bimodal distribution of submicron sized particles with micron sized particles of α-alumina to prepare the separator, improved cell performance was observed. Yet only a specific ratio of bimodal distribution achieved good results both in terms of separator formation and resulting cell performance. The interaction of α-alumina and binder in the separator, and its effect on the performance of substrate electrode was investigated, to understand the need for bimodal distribution of powder forming the separator.
ContributorsKanhere, Narayan Vishnu (Author) / Lin, Jerry Y. S. (Thesis advisor) / Kannan, Arunachala (Committee member) / Chan, Candace (Committee member) / Arizona State University (Publisher)
Created2017
Description
Before the rise in renewable energy, few people considered the consequences of adding large amounts of intermittent power onto the grid. As renewable energy has become more prevalent, utility companies must adapt their business practices to accommodate these unique sources of power. This is leading to challenges on how best to manage a grid with large amounts of renewable power. Arizona Public Service (APS), the largest electricity provider in the state of Arizona, has more than 70,000 distributed solar customers on their grid and the number of solar customers increases every day. With this increase in distributed solar customers comes the solar duck curve—the phenomenon whereby solar produces energy during times of low demand. However, with the use of storage, the duck curve problem may be mitigated. This project examines the sustainability of three storage options: pumped hydro energy storage, compressed air energy storage, and lithium-ion batteries. Using several sustainability indicators, this project makes a policy recommendation to APS on the most sustainable choice for large-scale energy storage. This project found that compressed air energy storage was the most sustainable option for APS. This considered the impacts of compressed air on the environment, communities, and the costs of this storage option. One important aspect to acknowledge regarding this technology is that in its current form, it does emit some carbon emissions. However, the carbon emissions may have less of an impact if this storage facility can allow APS to use its renewable energy assets most efficiently and continue to use energy from Palo Verde, the nuclear facility in Arizona.
ContributorsRood, Devon (Author) / Romito, Marc (Contributor)
Created2018-04-25