Thesis
Atomistic modeling of ionic liquid based electrolytes for lithium batteries
Washington State University
Master of Science (MS), Washington State University
2014
Handle:
https://hdl.handle.net/2376/100897
Abstract
The mobility of lithium ion in ionic liquid electrolytes is limited, mainly because of the size of the cations and the charged nature of the electrolyte. In this thesis, the mobility and transport characteristics of lithium ions in model N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide (mppy+ TFSI- ) ionic liquids is characterized using molecular dynamics method. Results from the simulations indicate that inclusion of organic additives such as ethylene carbonate, vinylene carbonate and tetrahydrofuran decreases the extent of coordination of the lithium ion with the anion of the ionic liquid and hence increases its mobility and partial ionic conductivity. The mobility of lithium ions in the ionic liquid based electrolyte increases with increasing concentration of the additive. Of the additives investigated, ethylene carbonate was identified as the most effective in increasing the mobility of lithium ions, while vinylene carbonate increases the overall ionic conductivity to the greatest extent. In an effort to understand the correlated motion and the mutual diffusion between the ions, the Maxwell Stephan diffusion coefficients of different ion pairs were evaluated for ionic liquid electrolyte without additives. The solubility of oxygen gas in pyrrolidinium based ionic liquids, which has not been investigated thus far, were calculated. Results for the solubility of oxygen in mppy+ TFSIindicate that the solubility of oxygen increases with increase in temperature. The solubility is low, as compared to organic additives, but it is comparatively higher than other ionic liquids. Comparison of these transport characteristics and solubility values with those of commonly used organic electrolytes tells us that ionic liquid electrolytes perform better at higher temperatures in lithium-air batteries as compared to organic electrolytes.
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Details
- Title
- Atomistic modeling of ionic liquid based electrolytes for lithium batteries
- Creators
- Anirudh Deshpande
- Contributors
- Soumik Banerjee (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Mechanical and Materials Engineering, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525390101842
- Language
- English
- Resource Type
- Thesis