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- Angenendt, Knut, 1982, et al.
(author)
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Ionic Liquid Based Lithium Battery Electrolytes: Charge Carriers and Interactions Derived by Density Functional Theory Calculations
- 2011
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In: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-5207 .- 1520-6106. ; 115:24, s. 7808-7813
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Journal article (peer-reviewed)abstract
- The solvation of lithium salts in ionic liquids (ILs) leads to the creation of a lithium ion carrying species quite different from those found in traditional nonaqueous lithium battery electrolytes. The most striking differences are that these species are composed only of ions and in general negatively charged. In many IL-based electrolytes, the dominant species are triplets, and the charge, stability, and size of the triplets have a large impact on the total ion conductivity, the lithium ion mobility, and also the lithium ion delivery at the electrode. As an inherent advantage, the triplets can be altered by selecting lithium salts and ionic liquids with different anions. Thus, within certain limits, the lithium ion carrying species can even be tailored toward distinct important properties for battery application. Here, we show by DFT calculations that the resulting charge carrying species from combinations of ionic liquids and lithium salts and also some resulting electrolyte properties can be predicted.
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| 2. |
- Angenendt, Knut, 1982, et al.
(author)
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Ionic liquid structures from large DFT calculations using mindless configurations
- 2010
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In: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 114:48, s. 20577-20582
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Journal article (peer-reviewed)abstract
- Three different popular imidazolium based ionic liquids (ILs); EMI-BF4, EMI-PF6, and EMI-TFSI, have been modeled by DFT calculations (B3LYP/6-311+G*) using large, up to 130 atom cluster models, for a better understanding of the structure and ion ion interactions in these ILs and ILs in general. Particular emphasis has been put on the role of appropriate starting structures and how the present large models differ from the ion-pair models of ILs generally used. The system size normalized ion ion interaction energies are shown to converge rapidly, and conformational equilibria and higher order properties like IR spectra are shown to be valuable as quality criteria. The explicit inclusion of an IL environment by the large cluster approach is also compared to using an implicit, continuum, strategy via SCRF C-PCM calculations.
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