First Principles Modeling of Structure and Transport in Solid Polymer Electrolytes, Ionic Liquids, and Methanol/Water Mixtures
Technical Report,20 Jul 2012,19 Oct 2015
University of Tennessee at Knoxville Knoxville United States
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We have undertaken simulations and calculations on three distinct systems 1 polyethylene oxide-alkali salts systems with the general formula PEO6XPF6, where X H, Li, or Na 2 methanolwater solution over a range of methanol mole fractions 0 to 1 and 3electrolytes for magnesium batteries incorporating chloro- or iodo- ionic liquids. Much of this work was done in collaboration with the experimental group of Prof. Vito Di Noto at the University of Padua, Italy. We have sought to understand structurefunction relationships using first principles based methods including ab initio molecular dynamics simulations and density functional theory based electronic structure calculations. Specifically, in crystalline PEO6XPF6 systems we confirmed that the dynamics of the chains play an important role in the diffusion mechanism and computed diffusion barriers for H, Li, and Na. In our AIMD simulations of the water-methanol mixtures we determined that at low methanol concentrations the water forms percolating hydrogen bond networks. When a moderate electric field was applied a hollow channel was observed in the methanol-rich mixtures. Finally, in our quantum chemical calculations of the magnesium battery electrolytes we were able to make all vibrational frequency assignments measured in the IR and Raman spectra and confirm the overall concatenated structure of the ionic liquids in the amorphous delta-Mg chlorideiodide.
- Quantum Theory and Relativity
- Physical Chemistry
- Atomic and Molecular Physics and Spectroscopy