Comparative study of poly(ethylene oxide) electrolytes made with LiN(CF3SO2)2, LiCF3SO3 and LiClO4: Thermal properties and conductivity behaviour

Vallée, Annie; Besner, Simon; Prud’homme, J.

doi:10.1016/0013-4686(92)80115-3

Cited by 335 publications

(302 citation statements)

References 4 publications

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“…The latter anions can be considered quasi-spherical and rigid, while the imides are quasi-linear and flexible. The imide internal rotational flexibility has proven a useful property demonstrated by the plasticizing effect of LiTFSI in polymer electrolytes 17 and by the wide liquid temperature range of the ILs they form. 18 Contrasting the linear and spherical anions is a third group of quasi-planar cyclic anions, such as 4,5-dicyano-1,2,3-triazolate (TADC), 19,20 and 4,5-dicyano-(2-trifluoromethyl)imidazolide (TDI).…”

Section: Introductionmentioning

confidence: 99%

Novel Lithium Imides; Effects of -F, -CF3, and -C≡N Substituents on Lithium Battery Salt Stability and Dissociation

et al. 2012

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New lithium imide salts have been studied using computational chemistry methods. Intrinsic anion oxidation potentials and ion pair dissociation energies are presented for six lithium sulfonyl imides (R-O 2 S-N-SO 2 -R) and six lithium phosphoryl imides (R 2 -OP-N-PO-R 2 ), as a function of -F, -CF 3 , and -C7N substitution. The modelled properties are used to estimate the electrochemical oxidation stability of the anions and the relative ease of charge carrier creation in lithium battery electrolytes. The results show that both properties are improved with cyanosubstitution, which in part is corroborated when comparing with other classes of lithium salts. However, the comparison also shows ambiguous oxidation stability results for cyano-substituted reference salts of the type PF x (CN) 6−x − and BF x (CN) 4−x − , using two different approaches -we present a tentative explanation for this. For the imide anions and PF 6 − , the bond dissociation energy is introduced as a third property, to gauge the thermal stability of the imide anions. The results suggest that the C-S and C-P bonds are the most liable to break and that the thermal stability is inversely related to the ion pair dissociation energy.

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Section: Introductionmentioning

confidence: 99%

Novel Lithium Imides; Effects of -F, -CF3, and -C≡N Substituents on Lithium Battery Salt Stability and Dissociation

et al. 2012

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“…[17][18][19] While these electrolytes exhibit reasonable conductivity at room temperature and lithium salts can be dissolved at high concentrations, the transference number based on the steady-state current method can be as low as 0.05. 20 This is due to specific interactions between the solvent and the cation.…”

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confidence: 99%

Effect of Anion Size on Conductivity and Transference Number of Perfluoroether Electrolytes with Lithium Salts

Shah

Olson

Karny

et al. 2017

J. Electrochem. Soc.

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Mixtures of perfluoropolyethers (PFPE) and lithium salts with fluorinated anions are a new class of electrolytes for lithium batteries. Unlike conventional electrolytes wherein electron-donating oxygen groups interact primarily with the lithium cations, the properties of PFPE-based electrolytes appear to be dependent on interactions between the fluorinated anions and the fluorinated backbones. We study these interactions by examining a family of lithium salts wherein the size of the fluorinated anion is systematically increased: lithium bis(fluorosulfonyl)imide (LiFSI), bis(trifluoromethanesulfonyl)imide (LiTFSI) salts and lithium bis(pentafluoroethanesulfonyl)imide (LiBETI). Two short chain perfluoroethers (PFE), one with three repeat units, C6-DMC, and another with four repeat units, C8-DMC were studied; both systems have dimethyl carbonate end groups. We find that LiFSI provides the highest conductivity in both C6-DMC and C8-DMC. These systems also present the lowest interfacial resistance against lithium metal electrodes. The steady-state transference number (t + ss ) was above 0.6 for all of the electrolytes and was an increasing function of anion size. The product of conductivity and the steady-state transference number, a convenient measure of the efficacy of the electrolytes for lithium battery applications, exhibited a maximum at about 20 wt% salt in all electrolytes. Amongst the systems studied, LiFSI/PFE mixtures were the most efficacious electrolytes.

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“…Using conservative values for LiClO 4 dissolved in PEO (64:1 molar ratio EO:Li+ at 50 °C) 41 and ϕ c = 0.23,, the estimated maximum σ BCE for a perfectly aligned system (f st = 1) is 0.028 mS/cm. Despite the observed increases in conductivity with alignment, even one as large as that achieved by the magnetic alignment methods of Majewski, et al, 17 the peak performance of a film of this BCE material has been experimentally measured to be 3 × 10 -3 mS/cm at 50 °C which remains an order of magnitude smaller than the maximum theoretical conductivity.…”

Section: Morphological Contributions To Conductivitymentioning

confidence: 99%

Ion Conduction in Microphase-Separated Block Copolymer Electrolytes

Kambe

Arges

Patel

et al. 2017

Electrochem. Soc. Interface

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Microphase separation of block copolymers provides a promising route towards engineering a mechanically robust ion conducting film for electrochemical devices. The separation into two different nano-domains enables the film to simultaneously exhibit both high ion conductivity and mechanical robustness, material properties inversely related in most homopolymer and random copolymer electrolytes. To exhibit the maximum conductivity and mechanical robustness, both domains would span across macroscopic length scales enabling uninterrupted ion conduction. One way to achieve this architecture is through external alignment fields that are applied during the microphase separation process. In this review, we present the progress and challenges for aligning the ionic domains in block copolymer electrolytes. A survey of alignment and characterization is followed by a discussion of how the nanoscale architecture affects the bulk conductivity and how alignment may be improved to maximize the number of participating conduction domains.

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Comparative study of poly(ethylene oxide) electrolytes made with LiN(CF3SO2)2, LiCF3SO3 and LiClO4: Thermal properties and conductivity behaviour

Cited by 335 publications

References 4 publications

Novel Lithium Imides; Effects of -F, -CF3, and -C≡N Substituents on Lithium Battery Salt Stability and Dissociation

Novel Lithium Imides; Effects of -F, -CF3, and -C≡N Substituents on Lithium Battery Salt Stability and Dissociation

Effect of Anion Size on Conductivity and Transference Number of Perfluoroether Electrolytes with Lithium Salts

Ion Conduction in Microphase-Separated Block Copolymer Electrolytes

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