| 1. |
- Hosseini Bab Anari, Elham, 1982, et al.
(författare)
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Fluorine-free salts for aqueous lithium-ion and sodium-ion battery electrolytes
- 2016
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 6:88, s. 6, 85194-85201
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Tidskriftsartikel (refereegranskat)abstract
- A first generation of fluorine-free lithium and sodium salts based on the concept of pseudo-delocalized anions has been synthesized with both high purity and yield using water as the solvent in the reaction medium. The salts have been fully characterized by Raman and FT-IR spectroscopies, thermogravimetry, and X-ray crystallography to reveal both basic properties in terms of thermal stability and solubility as well as the local, mainly ion–ion interaction dictated, coordination details and by ionic conductivity and electrochemical stability window measurements as aqueous electrolytes. Together a picture is created of the salts' promise as components in electrolytes – primarily aiming at application in low voltage fluorinefree aqueous lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs).
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| 2. |
- Mandai, Toshihiko, 1984, et al.
(författare)
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Haloaluminate-Free Cationic Aluminum Complexes: Structural Characterization and Physicochemical Properties
- 2016
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Ingår i: Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 120:38, s. 21285-21292
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Tidskriftsartikel (refereegranskat)abstract
- The large electrochemical activities of haloaluminate anions [AlnX3n+1](-), anionic complexes derived from AlX3 and Lewis basic fertilizers, have significantly contributed to the development of industrial coatings and more recently also to eledrochernical energy storage. In contrast, cationic metal complexes have just emerged as a class of species interesting as multivalent main charge carriers for Mg, Ca, and especially here Al batteries. Despite the potential of such complexes to efficiently deliver Al3+ cations at the electrode! electrolyte interfaces, very few cationic aluminum complexes that do not contain moisture sensitive [AlnX3n+1](-) counter anions have been reported due to the few, and difficult to synthesize, commercially available parent aluminum salts. Here a range of cationic aluminum complexes with different ligands and, anionic structures were successfully synthesized by complexation of AlCl3 with certain ligands to create fully solvated [Al(L)(6)]Cl-3 complexes and subsequent application of anion metathesis reactions. X-ray crystallography aided by vibrational spectroscopy corroborates the formation of discrete complexes with hexacoordinated octahedral Al3+ cations balanced by three isolated anions. The resulting physicochemical properties are strongly dependent on the constituent ions, and one special choice of ligand and anion results in a, novel design of a room temperature quasi-ionic liquid having high ionic conductivity. Although the high-melting complexes with DMSO ligands are inactive, the:molten complex exhibits both cathodic and anodic currents. This is the first electrolyte that allows quasi-reversible electrochemical plating/stripping of Al metal without any fragile anion being present.
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| 3. |
- 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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