Spectroscopic studies of ionic solvation in propylene carbonate

Yeager, H. L.; Fedyk, John D.; Parker, Richard

doi:10.1021/j100639a008

Cited by 80 publications

(46 citation statements)

References 6 publications

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“…Using the diffusion and bulk viscosity values the effective radii of the fluorinated BF 4 anion, lithium cation and PC molecules can now be determined. anion with increasing salt concentration at 303 K and 323 K. It can be seen from table 4 that the size of the lithium cation is the largest entity, this is due to the cation associating with several solvent molecules [33]. It has been observed elsewhere that on average four PC molecules will associate with a single lithium cation [34].…”

Section: Effective Ion Radiusmentioning

confidence: 88%

“…This is counter-intuitive as the lithium ions are the smallest entity and therefore since all ions and molecules are traveling through the same medium, should exhibit the largest diffusion coefficient. This was attributed to the fact that solvents such as PC which are polar protic, have been found to solvate the cation more favourably than the anion [33]. This is due to the cation having a high charge density which is more attractive than the dispersed charge of the anion.…”

Section: Nmr Self Diffusionmentioning

confidence: 99%

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Pulsed-Field Gradient NMR Self Diffusion and Ionic Conductivity Measurements for Liquid Electrolytes Containing LiBF4 and Propylene Carbonate

Richardson

Voice

Ward

2014

Electrochimica Acta

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Page 1 of 42A c c e p t e d M a n u s c r i p t 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 AbstractLiquid electrolytes have been prepared using lithium tetrafluoroborate (LiBF 4 ) and propylene carbonate (PC). Pulsed-field gradient nuclear magnetic resonance (PFG-NMR) measurements were taken for the cation, anion and solvent molecules using lithium ( 7 Li), fluorine ( 19 F) and hydrogen ( 1 H) nuclei, respectively. It was found that lithium diffusion was slow compared to the much larger fluorinated BF 4 anion likely resulting from a large solvation shell of the lithium. Ionic conductivity and viscosity have also been measured for a range of salt concentrations and temperatures. By comparing the measured conductivity with a ideal predicted conductivity derived from the Nernst-Einstein equation and self diffusion coefficients the degree of ionic association of the anion and cation was determined and was observed to increase with salt concentration and temperature. Using the measured viscosity and self diffusion coefficients the effective radius of each of the species was determined for various salt concentrations.

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Section: Effective Ion Radiusmentioning

confidence: 88%

Section: Nmr Self Diffusionmentioning

confidence: 99%

Pulsed-Field Gradient NMR Self Diffusion and Ionic Conductivity Measurements for Liquid Electrolytes Containing LiBF4 and Propylene Carbonate

Richardson

Voice

Ward

2014

Electrochimica Acta

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“…26,21,27 The spectra of organic compound would be especially affected by the presence of solvents and ions of the battery's electrolyte, collectively referred to as solvation effects. Thus, DEDOHC and poly-EC were introduced into the electrolyte, and FTIR spectra were acquired under the same condition as in in-situ and ex-situ experiments.…”

Section: Analysis Of LI Ion Solvation Effect On Dedohc and Poly-ec Irmentioning

confidence: 99%

Identification of Diethyl 2,5-Dioxahexane Dicarboxylate and Polyethylene Carbonate as Decomposition Products of Ethylene Carbonate Based Electrolytes by Fourier Transform Infrared Spectroscopy

et al. 2014

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The formation of passive films on electrode by electrolyte decomposition plays a crucial role in maintaining the reversibility of Li ion batteries (LIBs); however the understanding of the electrolyte decomposition process is still lacking. In this study, we investigated the decomposition of an electrolyte based on ethylene carbonate (EC) solvent, and identified the decomposition products on Sn and Ni surface by matching the IR spectra to that of synthesized reference compounds. The reference compounds diethyl 2,5-dioxahexane dicarboxylate (DEDOHC) and polyethylene carbonate (poly-EC) were synthesized and the chemical structures were characterized by nuclear magnetic resonance (NMR) andFourier transform infrared (FTIR) spectroscopy. Peak assignments were made based on quantum chemical (Hartree-Fock) calculations. By introducing the synthesized product compounds into the electrolyte, we studied the effect of Li-ion solvation on the IR spectra and were able to match the spectra of the decomposition products on Sn and Ni electrode surfaces to those of DEDOHC and poly-EC for the first time. This study clearly demonstrated the importance to include solvation effects in the IR spectra of reference compounds in identification of electrolyte decomposition products in LIBs.2

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“…A new peak at 2273 cm −1 was observed in the acetonitrile solution containing DDOE and LiPF 6 as shown in Figure 4 d. In acetone solution, shoulders appeared at 1215 and 1710 cm −1 . The shift and broadening of the absorption bands results from coordination of lithium ions to -CN 13 and -C=O, 14,15 respectively. The results suggest that lithium ions in the solution are more interactive with solvent molecules than oxetane molecules.…”

Section: Retardation Of the Polymerization Of Oxetane Derivatives Witmentioning

confidence: 99%

Polymerization of Bis-Oxetanes Consisting of Oligo-Ethylene Oxide Chain with Lithium Salts as Initiators

Miwa

Tsutsumi

Oishi

2001

Polym J

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ABSTRACT:New bis-oxetanes with oligo-ethylene oxide chain, 1,9-bis(3-ethyl-3-oxetanyl)-2,5,8-trioxanonane, 1,12-bis(3-ethyl-3-oxetanyl)-2,5,8,11-tetraoxadodecane, and 1,15-bis(3-ethyl-3-oxetanyl)-2,5,8,11,14-hexaoxapentadecane were prepared from 3-ethyl-3-hydroxymethyloxetane and di-, tri-, or tetra-ethylene glycol. Cationic ring-opening polymerization of bis-oxetanes with initiators based on various lithium salts such as LIBF 4 , LiPF 6 , LiN(CF 3 SO 2 ) 2 , and LiN(C 2 F 5 SO 2 ) 2 was investigated by FT-IR spectroscopy. Addition of lithium salts to the bis-oxetanes induced rapid and uncontrollable polymerization. Addition of polar solvents such as acetone, acetonitrile to the mixture containing the bis-oxetanes and lithium salts forbade polymerization. Removing the polar solvent from the mixture initiated polymerization and provided poly(oxetane)-lithium salt complexes that can be applied to solid polymer electrolytes. The kind of polar solvent and lithium salt and length of the ethylene oxide chains in the bis-oxetanes influenced reaction rates of the bis-oxetanes and crystallinities of the resulting poly(oxetane)-lithium salt complexes.KEY WORDS Ring-Opening Polymerization / Polyether / Lithium Salts / Oxetane / Polyethylene oxide (PEO), polypropylene oxide (PPO) and the polymers partially involving these structures have been much studied for applications to polymer electrolytes because they dissolve lithium salts, efficiently, and assist ion transport in the matrixes. 1, 2 These polymers are synthesized by ring-opening polymerization of cyclic ethers and the degree of polymerization for polymer electrolytes is controlled by anionic initiators. 3 These initiators should be removed perfectly from the polymer matrix because impurities derived from the initiators may affect ion transport in the polymer electrolyte and/or formation of passivating film on the electrodes (lithium and positive electrodes). 4 We investigated the preparation and polymerization of oxetane derivatives (DDOE, TrDOE, and TeDOE) as shown in Figure 1 to acquire polyether-like matrix that is similar to PEO and PPO (see Figure 2). Polymerization of the oxetane derivatives, initiated by various catalysts including cationic initiators 5-9 such as BF 3 , Figure 1. Synthesis of bis-oxetanes. † To whom correspondence should be addressed.AlCl 3 , SbCl 5 , PF 5 , Et 3 OPF 6 , Et 3 OBF 4 , and (C 4 H 9 ) 3 Al, was carried out lithium salts as initiators to obtain matrix polymers accessible for solid polymer electrolytes. However, direct preparation of poly(oxetane)-lithium salt complex from the mixture that consists of the oxetane monomer and a large amount of the salt, is not preferable for film formation because of rapid polymerization of the mixture. Solid polymer electrolytes must

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Spectroscopic studies of ionic solvation in propylene carbonate

Cited by 80 publications

References 6 publications

Pulsed-Field Gradient NMR Self Diffusion and Ionic Conductivity Measurements for Liquid Electrolytes Containing LiBF4 and Propylene Carbonate

Pulsed-Field Gradient NMR Self Diffusion and Ionic Conductivity Measurements for Liquid Electrolytes Containing LiBF4 and Propylene Carbonate

Identification of Diethyl 2,5-Dioxahexane Dicarboxylate and Polyethylene Carbonate as Decomposition Products of Ethylene Carbonate Based Electrolytes by Fourier Transform Infrared Spectroscopy

Polymerization of Bis-Oxetanes Consisting of Oligo-Ethylene Oxide Chain with Lithium Salts as Initiators

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