Date of Award

2018

Degree Type

Dissertation

Degree Name

Doctor of Philosophy in Chemistry

Department

Chemistry

First Advisor

Brett L. Lucht

Abstract

The development of energy storage technology is an important topic for facilitating the employment of renewable energy in society. Therefore, current energy storage research is heavily focused on enabling rechargeable high-energy density lithium-based batteries. In particular, permitting reversible electrochemical plating and stripping of the lithium metal negative electrode (or lithium metal anode) in carbonate electrolytes can achieve this goal. Unfortunately, the performance of the lithium metal anode in carbonate electrolytes is plagued by unsafe dendrite formation and poor Coulombic efficiency upon cycling. This dissertation attempts to reveal the role of the composition and structure of the Solid Electrolyte Interphase (SEI) in relation to the performance of the lithium metal anode. Galvanostatic voltammetry was used to characterize the electrochemistry of the lithium metal anode, with Infrared Spectroscopy, X-ray Photoelectron Spectroscopy, and Transmission Electron Microscopy to investigate the surface of the lithium metal anode. In chapter 2, a method to electrochemically synthesize lithium metal such that a reliable SEI is generated is introduced, using Cu||LiFePO4 cells. Using this method, in conjunction with the analytical techniques described above, chapters 3 and 4 investigates electrolyte components that significantly improve the performance of the lithium metal anode, fluoroethylene carbonate (FEC) and lithium difluoro(oxalate) borate (LiDFOB), with an explanation proposed. Finally, chapter 5 shows how FEC and LiDFOB can work together to optimize the SEI composition and structure, hence optimizing the performance of the lithium metal anode in carbonate electrolytes.

Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.