| DOI | Resolve DOI: https://doi.org/10.1149/1945-7111/abcf17 |
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| Author | Search for: Franko, Christopher J.1ORCID identifier: https://orcid.org/0000-0003-2577-1605; Search for: Yim, Chae-Ho1ORCID identifier: https://orcid.org/0000-0001-7321-1288; Search for: Årén, Fabian; Search for: Åvall, Gustav; Search for: Whitfield, Pamela S.1; Search for: Johansson, Patrik; Search for: Abu-Lebdeh, Yaser A.1; Search for: Goward, Gillian R.ORCID identifier: https://orcid.org/0000-0002-7489-3329 |
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| Affiliation | - National Research Council of Canada. Energy, Mining and Environment
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| Format | Text, Article |
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| Abstract | The physiochemical properties of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in adiponitrile (ADN) electrolytes were explored as a function of concentration. The phase diagram and ionic conductivity plots show a distinct relationship between the eutectic composition of the electrolyte and the concentration of maximum ionic conductivity in the 25 °C isotherm. We propose a structure-based explanation for the variation of electrolyte ionic conductivity with LiTFSI concentration, where the eutectic concentration is a transitionary region at which the structure changes from solvated contact ion pairs to extended units of [Liz(ADN)xTFSIy]ᶻ⁻ʸ aggregates. It is found through diffusion coefficient measurements using pulsed-field gradient (PFG) NMR that both ${D}_{Li}/{D}_{TFSI}$ and ${D}_{Li}/{D}_{ADN}$ increase with concentration until 2.9 M, where after Li+ becomes the fastest diffusing species, suggesting that ion hopping becomes the dominant transport mechanism for Li⁺. Variable diffusion-time (Δ) PFG NMR is used to track this evolution of the ion transport mechanism. A differentiation in Li⁺ transport between the micro and bulk levels that increases with concentration was observed. It is proposed that ion hopping within [Liz(ADN)xTFSIy]ᶻ⁻ʸ aggregates dominates the micro-scale, while the bulk-scale is governed by vehicular transport. Lastly, we demonstrate that LiTFSI in ADN is a suitable electrolyte system for use in Li-O₂ cells. |
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| Publication date | 2020-12-15 |
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| Publisher | IOP |
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| In | |
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| Language | English |
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| Peer reviewed | Yes |
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| Export citation | Export as RIS |
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| Report a correction | Report a correction (opens in a new tab) |
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| Record identifier | e0c4882d-ffc9-482f-9b43-ce0b950a41c9 |
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| Record created | 2022-01-10 |
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| Record modified | 2022-01-10 |
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