Identifying fast Li ions at the interfaces in composites of ionic liquids (EMIMTFSI) and Li salts (LiTFSI) by long-time 7Li NMR

Bernhard Stanje, Patrick Bottke, Ilie Hanzu, Maciej Marczewski, Patrick Johansson, Martin Wilkening

Research output: Contribution to conferencePosterResearchpeer-review

Abstract

New electrolytes are needed in lithium-based battery research in order to increase both safety and electrochemical performance. The mixture of an ionic liquid with a lithium salt represents a conceptually new class of electrolytes for high-temperature lithium batteries, termed ?ionic liquid-in-salt?. We used 7Li NMR spectroscopy, see, e.g., to study both local electronic structures and Li self-diffu¬sion in LiTFSI and LixEMIM(1-x)TFSI with x = 0.9. The NMR spectra, recorded under static conditions, perfectly agree with the results from differential scanning calorimetry. Upon heating to 513 K they clearly reveal several double phase regions; the known solid-state phase transformation of LiTFSI can be well recognized by the change of the quadruple powder pattern of the 7Li NMR spectra of LiTFSI. A rapid increase in long-range ion conductivity, within two orders of magnitudes, takes place when the 1/2 EMIMTFSI/LiTFSI phase starts to melt. This can also be monitored by tempera ture-variable 7Li spin-lattice relaxation (SLR) NMR. If recorded up to delay times of 1000 s, the pronounced bi-exponential 7Li SLR NMR transients found directly reveal a subset of highly mobile Li ions, partly identified as [Li(TFSI)2]-, which can be well discriminated from the response of pure LiTFSI. Most likely, this Li sub-ensemble, which is anticipated to be located at the LiTFSI:EMIMTFSI interfacial regions, is responsible for the enhanced ion conductivity observed.
Original languageEnglish
Publication statusPublished - 2016
EventE-MRS 2016 Spring Meeting - Lille, France
Duration: 2 May 20166 May 2016

Conference

ConferenceE-MRS 2016 Spring Meeting
CountryFrance
CityLille
Period2/05/166/05/16

Cite this

Stanje, B., Bottke, P., Hanzu, I., Marczewski, M., Johansson, P., & Wilkening, M. (2016). Identifying fast Li ions at the interfaces in composites of ionic liquids (EMIMTFSI) and Li salts (LiTFSI) by long-time 7Li NMR. Poster session presented at E-MRS 2016 Spring Meeting, Lille, France.

Identifying fast Li ions at the interfaces in composites of ionic liquids (EMIMTFSI) and Li salts (LiTFSI) by long-time 7Li NMR. / Stanje, Bernhard; Bottke, Patrick; Hanzu, Ilie; Marczewski, Maciej; Johansson, Patrick; Wilkening, Martin.

2016. Poster session presented at E-MRS 2016 Spring Meeting, Lille, France.

Research output: Contribution to conferencePosterResearchpeer-review

Stanje, B, Bottke, P, Hanzu, I, Marczewski, M, Johansson, P & Wilkening, M 2016, 'Identifying fast Li ions at the interfaces in composites of ionic liquids (EMIMTFSI) and Li salts (LiTFSI) by long-time 7Li NMR' E-MRS 2016 Spring Meeting, Lille, France, 2/05/16 - 6/05/16, .
Stanje B, Bottke P, Hanzu I, Marczewski M, Johansson P, Wilkening M. Identifying fast Li ions at the interfaces in composites of ionic liquids (EMIMTFSI) and Li salts (LiTFSI) by long-time 7Li NMR. 2016. Poster session presented at E-MRS 2016 Spring Meeting, Lille, France.
Stanje, Bernhard ; Bottke, Patrick ; Hanzu, Ilie ; Marczewski, Maciej ; Johansson, Patrick ; Wilkening, Martin. / Identifying fast Li ions at the interfaces in composites of ionic liquids (EMIMTFSI) and Li salts (LiTFSI) by long-time 7Li NMR. Poster session presented at E-MRS 2016 Spring Meeting, Lille, France.
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abstract = "New electrolytes are needed in lithium-based battery research in order to increase both safety and electrochemical performance. The mixture of an ionic liquid with a lithium salt represents a conceptually new class of electrolytes for high-temperature lithium batteries, termed ?ionic liquid-in-salt?. We used 7Li NMR spectroscopy, see, e.g., to study both local electronic structures and Li self-diffu¬sion in LiTFSI and LixEMIM(1-x)TFSI with x = 0.9. The NMR spectra, recorded under static conditions, perfectly agree with the results from differential scanning calorimetry. Upon heating to 513 K they clearly reveal several double phase regions; the known solid-state phase transformation of LiTFSI can be well recognized by the change of the quadruple powder pattern of the 7Li NMR spectra of LiTFSI. A rapid increase in long-range ion conductivity, within two orders of magnitudes, takes place when the 1/2 EMIMTFSI/LiTFSI phase starts to melt. This can also be monitored by tempera ture-variable 7Li spin-lattice relaxation (SLR) NMR. If recorded up to delay times of 1000 s, the pronounced bi-exponential 7Li SLR NMR transients found directly reveal a subset of highly mobile Li ions, partly identified as [Li(TFSI)2]-, which can be well discriminated from the response of pure LiTFSI. Most likely, this Li sub-ensemble, which is anticipated to be located at the LiTFSI:EMIMTFSI interfacial regions, is responsible for the enhanced ion conductivity observed.",
author = "Bernhard Stanje and Patrick Bottke and Ilie Hanzu and Maciej Marczewski and Patrick Johansson and Martin Wilkening",
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T1 - Identifying fast Li ions at the interfaces in composites of ionic liquids (EMIMTFSI) and Li salts (LiTFSI) by long-time 7Li NMR

AU - Stanje, Bernhard

AU - Bottke, Patrick

AU - Hanzu, Ilie

AU - Marczewski, Maciej

AU - Johansson, Patrick

AU - Wilkening, Martin

PY - 2016

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N2 - New electrolytes are needed in lithium-based battery research in order to increase both safety and electrochemical performance. The mixture of an ionic liquid with a lithium salt represents a conceptually new class of electrolytes for high-temperature lithium batteries, termed ?ionic liquid-in-salt?. We used 7Li NMR spectroscopy, see, e.g., to study both local electronic structures and Li self-diffu¬sion in LiTFSI and LixEMIM(1-x)TFSI with x = 0.9. The NMR spectra, recorded under static conditions, perfectly agree with the results from differential scanning calorimetry. Upon heating to 513 K they clearly reveal several double phase regions; the known solid-state phase transformation of LiTFSI can be well recognized by the change of the quadruple powder pattern of the 7Li NMR spectra of LiTFSI. A rapid increase in long-range ion conductivity, within two orders of magnitudes, takes place when the 1/2 EMIMTFSI/LiTFSI phase starts to melt. This can also be monitored by tempera ture-variable 7Li spin-lattice relaxation (SLR) NMR. If recorded up to delay times of 1000 s, the pronounced bi-exponential 7Li SLR NMR transients found directly reveal a subset of highly mobile Li ions, partly identified as [Li(TFSI)2]-, which can be well discriminated from the response of pure LiTFSI. Most likely, this Li sub-ensemble, which is anticipated to be located at the LiTFSI:EMIMTFSI interfacial regions, is responsible for the enhanced ion conductivity observed.

AB - New electrolytes are needed in lithium-based battery research in order to increase both safety and electrochemical performance. The mixture of an ionic liquid with a lithium salt represents a conceptually new class of electrolytes for high-temperature lithium batteries, termed ?ionic liquid-in-salt?. We used 7Li NMR spectroscopy, see, e.g., to study both local electronic structures and Li self-diffu¬sion in LiTFSI and LixEMIM(1-x)TFSI with x = 0.9. The NMR spectra, recorded under static conditions, perfectly agree with the results from differential scanning calorimetry. Upon heating to 513 K they clearly reveal several double phase regions; the known solid-state phase transformation of LiTFSI can be well recognized by the change of the quadruple powder pattern of the 7Li NMR spectra of LiTFSI. A rapid increase in long-range ion conductivity, within two orders of magnitudes, takes place when the 1/2 EMIMTFSI/LiTFSI phase starts to melt. This can also be monitored by tempera ture-variable 7Li spin-lattice relaxation (SLR) NMR. If recorded up to delay times of 1000 s, the pronounced bi-exponential 7Li SLR NMR transients found directly reveal a subset of highly mobile Li ions, partly identified as [Li(TFSI)2]-, which can be well discriminated from the response of pure LiTFSI. Most likely, this Li sub-ensemble, which is anticipated to be located at the LiTFSI:EMIMTFSI interfacial regions, is responsible for the enhanced ion conductivity observed.

M3 - Poster

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