Multifunctional separators for improving battery safety
- Rechargeable lithium-ion batteries have without a doubt transformed the world of portable electronics and consumer devices. However, recent high-profile failures of lithium-ion batteries caused by internal short-circuits have led to numerous fires and explosions. As the industry moves to higher energy-density electrode materials to satisfy consumer demand, the consequences and severity of failures will only increase. There is a clear need for improved safety mechanisms to enable the safe use of lithium-based batteries. Particularly for lithium metal electrodes where the continuous formation of dendrites during cycling increases the likelihood of failure by short-circuits. In this dissertation, I will discuss my work on developing in-situ detection and protection schemes using the battery separator as a platform. In the first part I will present an in-situ method for detecting the penetration of dendrites into the battery separator via a bifunctional separator with a conductive metal interlayer. Both metallic and carbon-based bifunctional separators are demonstrated with aluminum and carbon showing excellent stability in the battery environment. In the worst case scenario of a pinhole which extends through the entire separator, the advance warning preceding failure can be extended to several hours. In the second part, I will present a lithium cobalt oxide (LCO) coated separator which is demonstrated as a temperature sensor to reversibly and accurately measure the internal temperature of a battery. A heating fault is detected internally via the LCO separator as a 25C differential over the temperature measured at the cell surface. In the final section, the reaction of lithium with a silica nanoparticle-coated separator is demonstrated as a mechanism for suppressing the further growth of lithium dendrites which penetrate into the separator. This reaction-protective separator can greatly slow the growth of dendrites and extend the battery lifetime up to five times over traditional separators. Together these detection and protection schemes can be simultaneously used to improve the safety of lithium-based batteries.
|Type of resource
|electronic; electronic resource; remote
|1 online resource.
|Stanford University, Department of Materials Science and Engineering.
|Brongersma, Mark L
|Brongersma, Mark L
|Statement of responsibility
|Submitted to the Department of Materials Science and Engineering.
|Thesis (Ph.D.)--Stanford University, 2017.
- © 2017 by Denys Zhuo
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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