Quantifying degradation in lithium-metal and lithium-ion batteries
Abstract/Contents
- Abstract
- Batteries are a key technology for electrifying transportation and implementing a reliable, sustainable energy grid. A major limitation to the implementation and utilization of batteries in electric vehicles is the lower energy density compared to gasoline and their degradation over time. In this work, I investigate degradation in both next-generation battery materials and commercially available batteries on the market today. Lithium-metal negative electrodes provide a pathway to high specific-energy density. Multiple degradation pathways, including electrolyte reduction, lithium corrosion, and the formation of dead lithium, contribute to these losses, but few methods of characterization can distinguish the various modes of degradation. Here, I have developed a method of quantifying the amount of lithium metal in the electrode via operando X-ray diffraction (XRD). Through this method, how much lithium actively cycles and how much is lost to the three degradation mechanisms noted above can be separated and quantified. Additionally, the operando XRD experiments provide a unique measure of the corrosion current of electrodeposited lithium metal. The measurements reveal that lithium corrodes when electrically connected to the copper current collector as well as in the form of dead Li metal. Corrosion of the dead, electronically disconnected lithium provides new insight into corrosion mechanisms in lithium metal batteries. Additionally, I present an approach to electrochemically measure the active material and lithium capacity in commercial cells. This work complements a dataset of 400+ commercially available battery cells. Through fitting of the cells' charge/discharge voltage curves, the capacity of cyclable lithium and active material on both electrodes can be extrapolated throughout cell lifetime. The methods presented here validate the extrapolated values through electrochemical testing of the separated electrodes, which can be applied to confirm the understanding of predominant degradation modes in different cycling protocols. The approaches here address the quantification of capacity losses and a more complete understanding of degradation mechanisms, both of which can aid in the design of long-lasting batteries.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2021; ©2021 |
| Publication date | 2021; 2021 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Geise, Natalie R |
|---|---|
| Degree supervisor | Chidsey, Christopher E. D. (Christopher Elisha Dunn) |
| Degree supervisor | Toney, Michael Folsom |
| Thesis advisor | Chidsey, Christopher E. D. (Christopher Elisha Dunn) |
| Thesis advisor | Toney, Michael Folsom |
| Thesis advisor | Zare, Richard N |
| Degree committee member | Zare, Richard N |
| Associated with | Stanford University, Department of Chemistry |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Natalie Geise. |
|---|---|
| Note | Submitted to the Department of Chemistry. |
| Thesis | Thesis Ph.D. Stanford University 2021. |
| Location | https://purl.stanford.edu/mt860mt7017 |
Access conditions
- Copyright
- © 2021 by Natalie R Geise
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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