Thermoreversible polymer gel electrolytes

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.

Section: Introductionmentioning

confidence: 99%

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

2014

Electrochimica Acta

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“…These high conductivities were achieved with lithium salts and including the incorporation of N,N dimethylacetamide (DMAc) as a plasticiser [12]. The promising conductivities values achieved here led to a major research programme exploring thermoreversible polymer gel electrolytes based on poly(vinylidene fluoride) (PVDF) for use in advanced secondary battery applications [13].…”

Section: Conducting Polymer Electrolyte Research At the University Ofmentioning

confidence: 99%

“…The crystalline junctions will enter a melt if the melting temperature is exceeded due to the absence of chemical cross-links. These distinct properties of 2 PVDF have resulted in many publications on PGEs containing PVDF, as both the host polymer [13,14,15,16,17,18] and as part of co-polymer systems (such as PVDF-HFP) [19,20,21,22].…”

Section: Conducting Polymer Electrolyte Research At the University Ofmentioning

confidence: 99%

NMR self diffusion and relaxation time measurements for poly (vinylidene fluoride) (PVDF) based polymer gel electrolytes containing LiBF and propylene carbonate

2016

Polymer

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“…This was achieved at Leeds University with the addition of solvent to make polymer gel electrolytes (PGE) based on poly(N,N-dimethyl acrylamide) containing lithium salt [3]. This was followed by PGEs based on PVDF [4] which were found to be stable under 4V, which is needed for use in battery applications [5]. These gels are important as they offer many properties that traditional lithium ion batteries do not exhibit.…”

Section: Introductionmentioning

confidence: 99%

Two distinct lithium diffusive species for polymer gel electrolytes containing LiBF4, propylene carbonate (PC) and PVDF

International Journal of Hydrogen Energy

2014

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Polymer gel electrolytes have been prepared using lithium tetrafluoroborate (LiBF 4 ), propylene carbonate (PC) and polyvinylidene fluoride (PVDF) at 20% and 30% concentration by mass. Self diffusion coefficients have been measured using pulse field gradient nuclear magnetic resonance (PFG-NMR) for the cation and anion using 7 Li and 19 F resonant frequencies respectively. It was found that lithium ion diffusion was slow compared to the much larger fluorine anion likely resulting from a large solvation shell of the lithium. Lithium ion diffusion measurements exhibited two distinct diffusive species, whereas the fluorine ions exhibited only a single diffusive species.