Chemical and Biological Engineering ETDs

Publication Date

Spring 5-16-2020

Abstract

Li deposition at the graphitic anode is widely reported in literature as one of the leading causes of capacity fade in lithium-ion batteries (LIBs). Previous literature has also linked Li deposition resulting from low-temperature and high-rate ageing to diminished safety characteristics, however no current research has probed the effects of Li deposition on the abuse response of well- characterized cells. Additionally, no previous studies have investigated the use of an accelerated Li deposition technique for probing the effects of Li deposition. Using overtemperature testing, a relationship between increased concentrations of Li deposition and exacerbated abuse response in 1Ah pouch cells has been established. A novel Li deposition technique was also investigated, where cells with n:p < 1 (anode-limiting) were cycled at a high rate to exploit Li+ diffusion limitations at the anode. Scanning Electron Microscopy of harvested anodes indicates substantial Li deposition in low n:p cells after 20 cycles, with intricate networks of Li(s) deposits which hinder Li+ intercalation/deintercalation. Peak broadening and decreased amplitude of differential capacity plots further validates a loss of lithium inventory to Li+ dissolution, and Powder X-Ray Diffraction indicates Li+ intercalation with staging in anode interstitial sites as the extent of Li deposition increases. A cradle-to-grave approach is leveraged on cell fabrication and testing to eliminate uncertainty involving the effects of cell additives on Li deposition and other degradation mechanisms.

Keywords

Battery, Lithium, Lithium-ion, Deposition, Plating, Abuse

Document Type

Thesis

Language

English

Degree Name

Chemical Engineering

Level of Degree

Masters

Department Name

Chemical and Biological Engineering

First Committee Member (Chair)

Dr. Fernando Garzon

Second Committee Member

Dr. Sang M Han

Third Committee Member

Dr. Joshua Lamb

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