Solvate Ionic Liquid, [Li(triglyme)1][NTf2], as Electrolyte for Rechargeable Li–Air Battery: Discharge Depth and Reversibility

Tatara, Ryoichi; Tachikawa, Naoki; Kwon, Hoi Min; Ueno, Kazuhide; Dokko, Kaoru; Watanabe, Masayoshi

doi:10.1246/cl.130420

Cited by 29 publications

(29 citation statements)

References 18 publications

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“…The [Li(triglyme(G3)) 1 ][TFSI] solvate IL was used as the electrolyte of a rechargeable Li–air battery. This battery showed reversible ORR and OER characteristics, analogous to that of batteries with aprotic electrolytes . A [Li(TEGDME(G4)) 1 ][TFSI] solvate IL showed quasireversible ORR and OER behavior and high oxidative stability up to 4.5 V versus Li/Li + .…”

Section: Ionic‐liquid Electrolytesmentioning

confidence: 72%

Electrolytes for Rechargeable Lithium–Air Batteries

et al. 2019

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Lithium–air batteries are promising devices for electrochemical energy storage because of their ultrahigh energy density. However, it is still challenging to achieve practical Li–air batteries because of their severe capacity fading and poor rate capability. Electrolytes are the prime suspects for cell failure. In this Review, we focus on the opportunities and challenges of electrolytes for rechargeable Li–air batteries. A detailed summary of the reaction mechanisms, internal compositions, instability factors, selection criteria, and design ideas of the considered electrolytes is provided to obtain appropriate strategies to meet the battery requirements. In particular, ionic liquid (IL) electrolytes and solid‐state electrolytes show exciting opportunities to control both the high energy density and safety.

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Section: Ionic‐liquid Electrolytesmentioning

confidence: 72%

Electrolytes for Rechargeable Lithium–Air Batteries

et al. 2019

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“…In our previous study, 8 we applied a 1:1 mixture of Li salt and glyme for oxygen reduction/evolution. We have also recently shown that variation of the anion in such 1:1 solutions results in large differences in the amount of free glyme depending on the choice of Li salt.…”

Section: •¹mentioning

confidence: 99%

Effect of Anion in Glyme-based Electrolyte for Li-O₂ Batteries: Stability/Solubility of Discharge Intermediate

et al. 2017

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This study demonstrates that the amount of discharge product (Li 2 O 2 ) precipitated on the separator in a lithium oxygen cell using glyme-based electrolytes depends on the anion. The stability of the discharge intermediate (LiO 2 ) in the electrolyte has been shown to depend on the anionic species, which is related to Li 2 O 2 precipitation on the separator. The implications for producing an efficient and long-life Li-O 2 cell are elaborated. Keywords: Li-O 2 battery | Lithium superoxide | AnionThe Li-O 2 battery has been attracting a great deal of attention due to its high theoretical energy density.1 The solubility of the) is a critical parameter, because its solubility is believed to directly affect the morphology of the final discharge product, Li 2 O 2 .2 This morphology determines the rate of cathode clogging, thus also the maximum discharge capacity.2,3 The morphology has also been shown to affect the charging potential, 4 and thus directly influences the energy efficiency. However, a little-considered aspect is the extent to which the solubility of the O 2•¹ may allow the transport of reduced O 2 species away from the electrode. Nazar et al. reported SEM observation of discharge product deposition on glass fiber (separator) for a cell using 1 M lithium bis(trifluoromethanesulfonyl)amide (Li[TFSA])/tetraethylene glycol dimethyl ether (G4) electrolyte. 5 The implications, in terms of cell cyclability, of precipitation of discharge product on an electronically nonconductive component of the cell are self-evident. Moreover, Liu et al. have demonstrated the presence of large amounts of predominantly amorphous precipitates in the separator of a Li-O 2 battery using a 1 M lithium trifluoromethanesulfonate (Li[OTf])/ G4 electrolyte, and commented on their detrimental effects on cell overpotential and cyclability. 6 In their later work, they also reported X-ray diffraction-based evidence for crystalline Li 2 O 2 in the separator.7 A means to tune the degree of discharge product loss to the separator (and elsewhere in the cell) by variation of the electrolyte properties is thus desirable. The effect of variation of electrolyte, and in particular the anion, on this phenomenon has not yet been reported, to the best of our knowledge.In this study, we present an analysis of the variation of O 2•¹ solubility, and its subsequent effect on Li 2 O 2 distribution in the cell, for a series of glyme-based electrolyte solutions. In our previous study, 8 we applied a 1:1 mixture of Li salt and glyme for oxygen reduction/evolution. We have also recently shown that variation of the anion in such 1:1 solutions results in large differences in the amount of free glyme depending on the choice of Li salt. 9 Thus, to fully characterize the direct effect of the anion on the intermediate solubility and stability, we have chosen to explore more dilute solutions in this study, in which the effects may be more easily observed. The molar ratio of lithium salt to triethylene glycol dimethyl ether (G3) was kept constant (1:4), and the vario...

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“…24 Many researchers have also reported the fundamental properties and possible applications of solvate ILs. [10][11][12][13]35,36 On the basis of the similarity of the chemical nature among congeners, an appropriate combination of glymes and other alkali-metal salts should potentially form solvate ILs. [25][26][27][28][29][30] Theoretical calculations of equimolar glyme-alkali metal salts have been performed to obtain stable solvate structures.…”

Section: Introductionmentioning

confidence: 99%

Pentaglyme–K salt binary mixtures: phase behavior, solvate structures, and physicochemical properties

Mandai

Tsuzuki

Ueno

et al. 2015

Phys. Chem. Chem. Phys.

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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)2N](-) = [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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Solvate Ionic Liquid, [Li(triglyme)1][NTf2], as Electrolyte for Rechargeable Li–Air Battery: Discharge Depth and Reversibility

Cited by 29 publications

References 18 publications

Electrolytes for Rechargeable Lithium–Air Batteries

Electrolytes for Rechargeable Lithium–Air Batteries

Effect of Anion in Glyme-based Electrolyte for Li-O₂ Batteries: Stability/Solubility of Discharge Intermediate

Pentaglyme–K salt binary mixtures: phase behavior, solvate structures, and physicochemical properties

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Solvate Ionic Liquid, [Li(triglyme)1][NTf2], as Electrolyte for Rechargeable Li–Air Battery: Discharge Depth and Reversibility

Cited by 29 publications

References 18 publications

Electrolytes for Rechargeable Lithium–Air Batteries

Electrolytes for Rechargeable Lithium–Air Batteries

Effect of Anion in Glyme-based Electrolyte for Li-O2 Batteries: Stability/Solubility of Discharge Intermediate

Pentaglyme–K salt binary mixtures: phase behavior, solvate structures, and physicochemical properties

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Effect of Anion in Glyme-based Electrolyte for Li-O₂ Batteries: Stability/Solubility of Discharge Intermediate