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| 2. |
- Zhang, Chao, et al.
(författare)
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2023 Roadmap on molecular modelling of electrochemical energy materials
- 2023
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Ingår i: Journal of Physics. - : Institute of Physics Publishing (IOPP). - 2515-7655. ; 5:4
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Tidskriftsartikel (refereegranskat)abstract
- New materials for electrochemical energy storage and conversion are the key to the electrification and sustainable development of our modern societies. Molecular modelling based on the principles of quantum mechanics and statistical mechanics as well as empowered by machine learning techniques can help us to understand, control and design electrochemical energy materials at atomistic precision. Therefore, this roadmap, which is a collection of authoritative opinions, serves as a gateway for both the experts and the beginners to have a quick overview of the current status and corresponding challenges in molecular modelling of electrochemical energy materials for batteries, supercapacitors, CO2 reduction reaction, and fuel cell applications.
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| 3. |
- Mandai, Toshihiko, 1984, et al.
(författare)
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Pentaglyme-K salt binary mixtures: phase behavior, solvate structures, and physicochemical properties
- 2015
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Ingår i: Physical Chemistry Chemical Physics. - : Royal Society of Chemistry (RSC). - 1463-9084 .- 1463-9076. ; 17:4, s. 2838-2849
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Tidskriftsartikel (refereegranskat)abstract
- We prepared a series of binary mixtures composed of certain K salts (KX) and pentaglyme (G5) with different salt concentrations and anionic species ([X](-) : [(CF3SO2)(2)N](-) = [TFSA](-), [CF3SO3](-) = [TfO](-), [C4F9SO3](-) = [NfO](-), PF6-, SCN-), and characterized them with respect to their phase diagrams, solvate structures, and physicochemical properties. Their phase diagrams and thermal stability strongly implied the formation of equimolar complexes. Single-crystal X-ray crystallography was performed on certain equimolar complexes, which revealed that G5 molecules coordinate to K+ cations in a characteristic manner, like 18-crown-6 ether in the crystalline state, irrespective of the paired anions. The solvate structures in the molten state were elucidated by a combination of temperature-dependent Raman spectroscopy and X-ray crystallography. A drastic spectral variation was observed in the [K(G5)(1)][TfO] Raman spectra, indicating that solvate structures in the crystalline state break apart upon melting. The solvate stability of [K(G5)(1)]X is closely related to the ion-ion interaction of the parent salts. A stable solvate forms when the ion-dipole interaction between K+ and G5 overwhelms the ion-ion interaction between K+ and X-. Furthermore, the physicochemical properties of certain equimolar mixtures were evaluated. A Walden plot clearly reflects the ionic nature of the molten equimolar complexes. Judging from the structural characteristics and dissociativity, we classified [K(G5)(1)]X into two groups, good and poor solvate ionic liquids.
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| 7. |
- Terada, S., et al.
(författare)
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Thermal and Electrochemical Stability of Tetraglyme-Magnesium Bis(trifluoromethanesulfonyl)amide Complex: Electric Field Effect of Divalent Cation on Solvate Stability
- 2016
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 120:3, s. 1353-1365
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Tidskriftsartikel (refereegranskat)abstract
- Phase behavior of binary mixtures of tetraglyme (G4) and Mg[TFSA]2 (TFSA: bis(trifluoromethanesulfonyl)amide) was investigated. In a 1:1 molar ratio, G4 and Mg[TFSA]2 formed a stable complex with a melting point of 137 degrees C. X-ray crystallography of a single crystal of the complex grown from a G4-Mg[TFSA]2 binary mixture revealed that the G4 molecule wraps around Mg2+ to form a complex [Mg(G4)](2+) cation, and the two [TFSA](-) anions also participate in the Mg2+ coordination in the crystal. The thermal stability of [Mg(G4)][TFSA](2) was examined by thermogravimetry, and it was found that the complex is stable up to 250 degrees C. Above 250 degrees C, desolvation of the Mg2+ ion takes place and G4 evaporates. On the other hand, the weight loss starts at around 140 degrees C in solutions containing excess G4 (n > 1 in Mg[TFSA]2:G4 = 1:n) due to the evaporation of free (uncoordinated) G4. The suppression of G4 volatility in the [Mg(G4)][TFSA]2 complex is attributed to strong electrostatic and induction interactions between divalent Mg2+ and G4. In addition, complexation of G4 with Mg2+ is effective in enhancing the oxidative stability of G4. Linear sweep voltammetry revealed that the oxidative decomposition of [Mg(G4)][TFSA]2 occurs at electrode potentials >5 V vs Li/Li+, while the oxidation of uncoordinated G4 occurs at around 4.0 V. This oxidative stability enhancement occurs because the HOMO energy level of G4 is reduced by complexation with Mg2+, which is supported by the ab initio calculations.
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