Understanding of the transport phenomena in Li-air batteries is crucial for improving the performance and design of Li-air batteries. In this dissertation, the basic transport equations that govern the operation of Li-air batteries are derived by starting from the underlying mass and charge transport properties of the chemical species involved in the operation of the battery. Then, two approaches are presented to solve the transport equations. In the first approach, we use first-order approximations to derive a compact model for the discharge voltage of Li-air batteries with organic electrolyte. The model considers oxygen transport and volume change in the cathode, and Butler-Volmer kinetics at the anode and cathode electrodes, and is particularly useful to the fast prediction of the discharge voltage and specific capacities of Li-air batteries. In the second approach, we propose a finite-element model in which the basic transport equations are discretized over a finite space-time mesh and solved numerically to predict the battery characteristics under different discharge conditions and for different geometrical and physical parameters. Then, the transport equations are reexamined and improved to account for different pore microstructures, pore size distribution effects, and electron transport mechanisms through the discharge product. The different microstructures are simulated numerically and the performance of Li-air batteries is analyzed in each case. A novel hybrid model is introduced to explain the perceived transition from one microstructure to another. / A Dissertation submitted to the Department of Electrical and Computer Engineering in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Summer Semester 2015. / July 13, 2015. / Cathode, Compact model, Energy density, Li-air, Microstrucuture, Nanofibers / Includes bibliographical references. / Petru Andrei, Professor Directing Dissertation; Anke Meyer-Baese, University Representative; Jim Zheng, Committee Member; Simon Foo, Committee Member.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_253195 |
| Contributors | Bevara, Vamsci Venkat (authoraut), Andrei, Petru (professor directing dissertation), Meyer-Baese, Anke (university representative), Zheng, Jianping P. (committee member), Foo, Simon Y. (committee member), Florida State University (degree granting institution), FAMU-FSU College of Engineering (degree granting college), Department of Electrical and Computer Engineering (degree granting department) |
| Publisher | Florida State University, Florida State University |
| Source Sets | Florida State University |
| Language | English, English |
| Detected Language | English |
| Type | Text, text |
| Format | 1 online resource (127 pages), computer, application/pdf |
| Rights | This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). The copyright in theses and dissertations completed at Florida State University is held by the students who author them. |
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