| 1. |
- Engström, Niklas, 1985, et al.
(author)
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Towards Celiac-safe foods: Decreasing the affinity of transglutaminase 2 for gliadin by addition of ascorbyl palmitate and ZnCl2 as detoxifiers
- 2017
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322 .- 2045-2322. ; 7:77
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Journal article (peer-reviewed)abstract
- Initiation of celiac disease is triggered in the gastrointestinal tract by transglutaminase 2 (TG2) assisted deamidation of gluten peptides. Deamidation is a side-reaction to transamidation and occurs if primary amines are absent. In contrast to deamidation, transamidation does not trigger an immune response. The aim of the study was to identify a suitable food additive that interacts with TG2 binding motives in gluten-derived peptides to prevent deamidation/transamidation. Homology modelling of alpha 2-gliadin and computational screening of compounds for their binding affinity to a common TG2 binding motive (P) QLP were done by using computational approaches followed by experimental testing of TG2 activity. A database containing 1174 potential food grade ligands was screened against the model of alpha 2-gliadin (27 out of 33 aa). Out of the five best ligands, ascorbyl palmitate, was observed to decrease TG2 transamidation of gliadin by 82% +/- 2%. To completely silence the transamidation, we added zinc chloride (ZnCl2), and thereby reached a 99% +/- 1% inhibition of TG2 activity. In addition, we conducted a pilot experiment in which ascorbyl palmitate was observed to decrease TG2 deamidation of gliadin completely. We propose ascorbyl palmitate in combination with ZnCl2 with the future perspective to become an additive in celiac-safe foods.
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| 2. |
- Aguilera Medina, Luis, 1983, et al.
(author)
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A structural study of LiTFSI-tetraglyme mixtures: From diluted solutions to solvated ionic liquids
- 2015
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In: Journal of Molecular Liquids. - : Elsevier BV. - 0167-7322. ; 210:Part B, s. 238-242
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Journal article (peer-reviewed)abstract
- We report on the nano-structure of solvated ionic liquids (SILs) formed by dissolving a Li-salt (LiTFSI) in the solvent tetraglyme. Using small angle X-ray scattering (SAXS), supported by Raman spectroscopy and computational modeling we follow how the nano-structure develops as Li-salt is added to the solvent. We find that, as the Li-salt concentration is increased a peak at Q 0.95 Å- 1 grows in intensity, signaling the presence of structural correlations typical of those found in traditional ionic liquids. The intensity of the peak reaches its maximum at the equimolar concentration, where each Li-ion can be solvated by one solvent molecule forming an effective cation complex. Combining the SAXS data with computer modeling we show that this peak can be assigned to charge alternation, also found in traditional ionic liquids. However, we also show that even at the equimolar concentration not all Li-ions are solvated by the solvent molecules, but a small fraction interacts directly with the anion (TFSI).
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| 3. |
- Aguilera Medina, Luis, 1983, et al.
(author)
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Enhanced low-temperature ionic conductivity via different Li+ solvated clusters in organic solvent/ionic liquid mixed electrolytes
- 2016
-
In: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9084 .- 1463-9076. ; 18:36, s. 25458-25464
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Journal article (peer-reviewed)abstract
- We investigate Li+ coordination in mixed electrolytes based on ionic liquids (ILs) and organic solvents and its relation with the macroscopic properties such as phase behaviour and ionic conductivity. Using Raman spectroscopy we determine the solvation shell around Li+ in mixtures formed by the IL N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide, the organic solvents ethylene carbonate and dimethyl carbonate (EC : DMC 1 : 1), and the salt LiTFSI. We find that the organic solvent molecules preferentially solvate Li+ as long as there are enough of them. Our results are consistent with a model where Li(EC)(3)(DMC)(1) and Li(EC)(2)(DMC)(2) are the main complexes formed by the organic solvent molecules and where TFSI- mainly participates in Li(TFSI)(2)(-) clusters. As the amount of organic solvent is increased, the number of TFSI- around Li+ rapidly decreases showing a higher affinity of the organic solvents to solvate Li+. The changes in the local configurations are also reflected in the ionic conductivity and the phase behaviour. The formation of larger clusters leads to a decrease in the conductivity, whereas the presence of several different clusters at intermediate compositions effectively hinders crystallization at low temperatures. The result is an enhanced low-temperature ionic conductivity in comparison with the pure IL or organic solvent electrolytes.
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| 4. |
- Böhme, Solveig, et al.
(author)
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Lithium-ion batteries based on SnO2 electrodes and a LiTFSI-Pip14TFSI ionic liquid electrolyte
- 2017
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In: Journal of the Electrochemical Society. - : The Electrochemical Society. - 1945-7111 .- 0013-4651. ; 164:4, s. A701-A708
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Journal article (peer-reviewed)abstract
- The performance of lithium-ion batteries (LIBs) comprising SnO2 electrodes and an ionic liquid (IL) based electrolyte, i.e., 0.5 M LiTFSI in Pip14TFSI, has been studied at room temperature (i.e., 22°C) and 80°C. While the high viscosity and low conductivity of the electrolyte resulted in high overpotentials and low capacities at room temperature, the SnO2 performance at 80°C was found to be analogous to that seen at room temperature using a standard LP40 electrolyte (i.e., 1 M LiPF6 dissolved in 1:1 ethylene carbonate and diethyl carbonate). Significant reduction of the IL was, however, found at 80°C, which resulted in low coulombic efficiencies during the first 20 cycles, most likely due to a growing SEI layer and the formation of soluble IL reduction products. X-ray photoelectron spectroscopy studies of the cycled SnO2 electrodes indicated the presence of an at least 10 nm thick solid electrolyte interphase (SEI) layer composed of inorganic components such as lithium fluoride, sulfates, and nitrides as well as organic species containing C-H, C-F and C-N bonds.
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| 5. |
- Hannauer, J., et al.
(author)
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The Quest for Polysulfides in Lithium-Sulfur Battery Electrolytes: An Operando Confocal Raman Spectroscopy Study
- 2015
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In: ChemPhysChem. - : Wiley. - 1439-7641 .- 1439-4235. ; 16:13, s. 2755-2759
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Journal article (peer-reviewed)abstract
- Confocal Raman spectra of a lithium-sulfur battery electrolyte are recorded operando in a depth-of-discharge resolved manner for an electrochemical cell with a realistic electrolyte/sulfur loading ratio. The evolution of various possible polysulfides is unambiguously identified by combining Raman spectroscopy data with DFT simulations.
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| 6. |
- Hellberg, Lars, 1960, et al.
(author)
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Master students learning TRIZ at the University: past experiences, future plans, and best practices
- 2016
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In: 12th MATRIZ TRIZfest-2016 International Conference, July 28-30, Beijing, People’s Republic of China. - 2374-2275. - 9780692524183
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Conference paper (peer-reviewed)abstract
- Creating an efficient learning environment for TRIZ at a university is far from trivial. Although the TRIZ-tools for solving problems can appear simple at a glance, applying them to real world problems by beginners is not. In this paper we share our experiences teaching and developing a university course in TRIZ for Master students with different Engineering backgrounds. The syllabus of the course is presented, student results and feedback are analyzed, and plans for future course development are discussed.
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| 7. |
- Kerner, Manfred, 1984, et al.
(author)
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Ionic liquid based lithium battery electrolytes: fundamental benefits of utilising both TFSI and FSI anions?
- 2015
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In: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9084 .- 1463-9076. ; 17:29, s. 19569-19581
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Journal article (peer-reviewed)abstract
- Several IL based electrolytes with an imidazolium cation (EMI) have been investigated trying to elucidate a possible beneficial effect of mixing FSI and TFSI anions in terms of physico-chemical properties and especially Li+ solvation. All electrolytes were evaluated in terms of phase transitions, densities and viscosities, thermal stabilities, ionic conductivities and local structure, i.e. charge carriers. The electrolytes with up to 20% of Li-salts showed to be promising for high temperature lithium ion battery application (ca. 100°C) and a synergetic effect of having mixed anions is discernible with the LiTFSI0.2EMIFSI0.8 electrolyte giving the best overall performance. The determination of the charge carriers revealed the SN to be ca. 2 for all analysed electrolytes, and proved the analysis of the mixed anion electrolytes to be challenging and inherently leads to an ambiguous picture of the Li+ solvation.
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| 8. |
- Kerner, Manfred, 1984, et al.
(author)
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Thermal stability and decomposition of lithium bis(fluorosulfonyl)imide (LiFSI) salts
- 2016
-
In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 6:28, s. 23327-23334
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Journal article (peer-reviewed)abstract
- The demand for lithium-ion battery (LIB) electrolytes with improved thermal stabilities, and maintained high ionic conductivities and electrochemical stabilities, has been the driving force behind the use of the lithium bis(fluorosulfonyl)imide (LiFSI) salt as a possible replacement for LiPF6. However, contradictory results have questioned its promising thermal stability and noncorrosive properties. Here the performance of three commercial LiFSI salts is compared with the focus on thermal stability and phase transitions together with a vibrational spectroscopy based assessment of the salt purity and decomposition products. The salts are found to differ significantly in their thermal stabilities as determined by both dynamic and isothermal TGA. In contrast, the FT-IR spectra of the salts are almost identical, while several additional bands are identified in the Raman spectra of the least stable salt. The latter allows for a discussion of the origin and role of salt impurities for the observed thermal (in-)stability. Overall the three salts show differences, but these differences are not straightforward to couple to any changes in the performance of Li/LiFePO4 cells using electrolytes based on these salts, but may nevertheless have implications on battery life-length and for application in various other battery technologies.
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| 9. |
- Kerner, Manfred, 1984, et al.
(author)
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Towards more thermally stable Li-ion battery electrolytes with salts and solvents sharing nitrile functionality
- 2016
-
In: Journal of Power Sources. - : Elsevier BV. - 0378-7753. ; 332, s. 204-212
-
Journal article (peer-reviewed)abstract
- The overall safety of Li-ion batteries is compromised by the state-of-the-art electrolytes; the thermally unstable lithium salt, lithium hexafluorophosphate (LiPF6), and flammable carbonate solvent mixtures. The problem is best addressed by new electrolyte compositions with thermally robust salts in low flammability solvents. In this work we introduce electrolytes with either of two lithium nitrile salts, lithium 4,5-dicyano-1,2,3-triazolate (LiDCTA) or lithium 4,5-dicyano-2-trifluoromethylimidazolide (LiTDI), in solvent mixtures with high flashpoint adiponitrile (ADN), as the main component. With sulfolane (SL) and ethylene carbonate (EC) as co-solvents the liquid temperature range of the electrolytes are extended to lower temperatures without lowering the flashpoint, but at the expense of high viscosities and moderate ionic conductivities. The anodic stabilities of the electrolytes are sufficient for LiFePO4 cathodes and can be charged/discharged for 20 cycles in Li/LiFePO4 cells with coulombic efficiencies exceeding 99% at best. The excellent thermal stabilities of the electrolytes with the solvent combination ADN:SL are promising for future electrochemical investigations at elevated temperatures (> 60 degrees C) to compensate the moderate transport properties and rate capability. The electrolytes with EC as a co-solvent, however, release CO2 by decomposition of EC in presence of a lithium salt, which potentially makes EC unsuitable for any application targeting higher operating temperatures.
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| 10. |
- Kim, Jae-Kwang, 1978, et al.
(author)
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A layer-built rechargeable lithium ribbon-type battery for high energy density textile battery applications
- 2014
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In: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 2:6, s. 1774-1780
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Journal article (peer-reviewed)abstract
- We designed a novel layer-built rechargeable lithium ribbon-type battery intended for textile or cloth based applications. The ribbon-type battery, 2.4 mm (or 1 mm) wide and 10 cm long, is composed of a double layer LiFePO4 cathode and an amorphous silicon nanofilm. The double layer LiFePO4 and amorphous silicon electrodes were prepared using the doctor blade method and a vertical deposition technique, respectively. The structure and morphology of the LiFePO4 and the silicon thin film were characterized by Rietveld refinement, SEM and TEM. At room temperature the ribbon-type battery exhibited an initial discharge capacity of 166.4 and 132.7 mA h g (1) at 0.5 and 1 C-rate, respectively. A reasonably good cycling performance and high coulombic efficiency under the high current density of 1 C-rate could be obtained with the Si/LiFePO4 ribbon-type battery. Also, a high volumetric capacity of 336 mA h cm (3) at 0.5 C-rate was achieved, which makes the ribbon-type battery suitable for practical use.
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