| 1. |
- Holomb, Roman, et al.
(författare)
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Vibrational spectroscopy and ab initio studies of lithium bis (oxalato) borate (LiBOB) in different solvents
- 2006
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Ingår i: Journal of Physical Chemistry A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 110:40, s. 11467-11472
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Tidskriftsartikel (refereegranskat)abstract
- The effect of lithium ion coordination with the bis(oxalato)borate (BOB ) [6(0204)2] anion in DMSO, PEG, PPG, and d-PPG has been studied in detail by IR and Raman spectroscopy. Ab initio calculations were performed to allow a consistent analysis of the experimental data. The main features observed in the IR and Raman spectra correspond to the presence of "free", un-coordinated, BOB - anions. Only with use of d-PPG as solvent a small amount of Li + ⋯BOB - ion pairs were detected. The Raman spectra and the calculations together indicate that Li + coordinates bidentately with two end-oxygen atoms of the BOB - anion. The identification of ion pairs can be used to reveal limitations of LiBOB based electrolytes. The results for LiBOB are compared with literature on other Li salts. © 2006 American Chemical Society.
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| 2. |
- Markusson, Henrik, 1976, et al.
(författare)
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Electrochemical stability and lithium ion-anion interactions of orthoborate anions (BOB, MOB, BMB), and presentation of a novel anion: Tris-oxalato-phosphate
- 2005
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Ingår i: Electrochemical and Solid-State Letters. - : The Electrochemical Society. - 1099-0062. ; 8:4, s. A215-A218
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Tidskriftsartikel (refereegranskat)abstract
- Ab initio calculations reveal the extraordinary low lithium ion affinities of the orthoborate anions bis(oxalate)borate (BOB), malonato-oxalatoborate (MOB), and bis(malonato)borate (BMB). HF and MP2 calculations reveal these anions to be less prone to associate with Li + (by ∼10%) than most anions used today, e.g., PF 6 - , BF 4 - , and TFSI, in low dielectric media such as polymeric electrolytes. Furthermore, by using self-consistent reaction field calculations to model the effect of high dielectric solvents present, the applicability of these anions also for liquid and gel electrolytes was proven. Future directions of lithium salt synthesis are outlined and exemplified by a new anion, suggested here for the first time. The HOMO levels of the anions are correlated to electrochemical stabilities in electrolytic solutions; all studied anions can be anticipated to have wide stability ranges. Finally, a new methodology to obtain starting data for geometry optimizations of cation-anion pairs by global optimization is presented. © 2005 The Electrochemical Society. All rights reserved.
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| 3. |
- Markusson, Henrik, 1976, et al.
(författare)
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IR spectroscopy and quantum mechanical calculations of lithium ion transport conditions in a single ion conducting polymer electrolyte
- 2004
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Ingår i: Polymer. - : Elsevier BV. - 0032-3861. ; 45:26, s. 9057-9065
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Tidskriftsartikel (refereegranskat)abstract
- Lithium single ion conducting polymers with good conductive properties has the potential of boosting the performance of lithium batteries considerably. Recently, lithium single ion conducting polymer electrolytes were obtained by solvating 'polymeric salts' into polyether matrices. Of the polymeric salts developed, the highest ion conductivity was obtained using poly(5-oxo-3-oxy-4- trifluoromethyl-1,2,4-pentafluoro-pentylene sulphonyl imide lithium) (LiPPI). In the present study ab initio calculations have been used to determine limitations for ion transport in a model system similar to the LiPPI. The lithium ion coordination and the flexibility of the polymer backbone have been studied using monomers and dimers of our model system. Comparisons with calculated IR spectra from our model system and experimental IR spectra of LiPPI in solution show that our model is a good description of the LiPPI system. The present results are used to propose structural changes that may increase the single ion conductivity. © 2004 Elsevier Ltd. All rights reserved.
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| 4. |
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| 5. |
- Markusson, Henrik, 1976, et al.
(författare)
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Prediction of macroscopic properties of protic ionic liquids by ab initio calculations
- 2007
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Ingår i: Journal of Physical Chemistry A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 111:35, s. 8717-8723
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Tidskriftsartikel (refereegranskat)abstract
- We have systematically investigated combinations of anions and cations in a number of protic ionic liquids based on alkylamines and used ab initio methods to gain insight into the parameters determining their liquid range and their conductivity. A simple, almost linear, relation of the experimentally determined melting temperature with the calculated volume of the anion forming the ionic liquid is found, whereas the dependence of the melting temperature with increasing cation volume goes through a minimum for relatively short side chain length. On the basis of the present results, we propose a strategy to predict the nature of protic ionic liquids in terms of low vapor pressure and conductivity. Comparisons with previously reported strategies for prediction of melting temperatures for aprotic ionic liquids are also made. © 2007 American Chemical Society.
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