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Leier J, Michenfelder NC, Unterreiner A. Understanding the Photoexcitation of Room Temperature Ionic Liquids. ChemistryOpen 2021; 10:72-82. [PMID: 33565733 PMCID: PMC7874249 DOI: 10.1002/open.202000278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 10/26/2020] [Indexed: 12/14/2022] Open
Abstract
Photoexcitation of (neat) room temperature ionic liquids (RTILs) leads to the observation of transient species that are reminiscent of the composition of the RTILs themselves. In this minireview, we summarize state-of-the-art in the understanding of the underlying elementary processes. By varying the anion or cation, one aim is to generally predict radiation-induced chemistry and physics of RTILs. One major task is to address the fate of excess electrons (and holes) after photoexcitation, which implies an overview of various formation mechanisms considering structural and dynamical aspects. Therefore, transient studies on time scales from femtoseconds to microseconds can greatly help to elucidate the most relevant steps after photoexcitation. Sometimes, radiation may eventually result in destruction of the RTILs making photostability another important issue to be discussed. Finally, characteristic heterogeneities can be associated with specific physicochemical properties. Influencing these properties by adding conventional solvents, like water, can open a wide field of application, which is briefly summarized.
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Affiliation(s)
- Julia Leier
- Institute of Physical ChemistryKarlsruhe Institute of Technology (KIT)Fritz-Haber-Weg 276131KarlsruheGermany
| | - Nadine C. Michenfelder
- Institute of Physical ChemistryKarlsruhe Institute of Technology (KIT)Fritz-Haber-Weg 276131KarlsruheGermany
| | - Andreas‐Neil Unterreiner
- Institute of Physical ChemistryKarlsruhe Institute of Technology (KIT)Fritz-Haber-Weg 276131KarlsruheGermany
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Steinrück H, Cao C, Lukatskaya MR, Takacs CJ, Wan G, Mackanic DG, Tsao Y, Zhao J, Helms BA, Xu K, Borodin O, Wishart JF, Toney MF. Interfacial Speciation Determines Interfacial Chemistry: X-ray-Induced Lithium Fluoride Formation from Water-in-salt Electrolytes on Solid Surfaces. Angew Chem Int Ed Engl 2020; 59:23180-23187. [PMID: 32881197 PMCID: PMC7756515 DOI: 10.1002/anie.202007745] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Indexed: 11/17/2022]
Abstract
Super-concentrated "water-in-salt" electrolytes recently spurred resurgent interest for high energy density aqueous lithium-ion batteries. Thermodynamic stabilization at high concentrations and kinetic barriers towards interfacial water electrolysis significantly expand the electrochemical stability window, facilitating high voltage aqueous cells. Herein we investigated LiTFSI/H2 O electrolyte interfacial decomposition pathways in the "water-in-salt" and "salt-in-water" regimes using synchrotron X-rays, which produce electrons at the solid/electrolyte interface to mimic reductive environments, and simultaneously probe the structure of surface films using X-ray diffraction. We observed the surface-reduction of TFSI- at super-concentration, leading to lithium fluoride interphase formation, while precipitation of the lithium hydroxide was not observed. The mechanism behind this photoelectron-induced reduction was revealed to be concentration-dependent interfacial chemistry that only occurs among closely contact ion-pairs, which constitutes the rationale behind the "water-in-salt" concept.
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Grants
- Joint Center for Energy Storage Research (JCESR).
- DE-SC0012704 Chemical Sciences, Geosciences, and Biosciences Division
- ECCS-1542152 National Science Foundation
- DE-AC02-76SF00515 U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences
- DE-AC02-05CH11231 Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy
- ECCS-2026822 National Science Foundation
- SN2020957 Joint Center for Energy Storage Research (JCESR) / ARL
- Chemical Sciences, Geosciences, and Biosciences Division
- National Science Foundation
- U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences
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Affiliation(s)
- Hans‐Georg Steinrück
- SSRL Materials Science DivisionSLAC National Accelerator LaboratoryMenlo ParkCA94025USA
- SLAC National Accelerator LaboratoryJoint Center for Energy Storage Research (JCESR)LemontIL60439USA
- Department ChemieUniversität Paderborn33098PaderbornGermany
| | - Chuntian Cao
- SSRL Materials Science DivisionSLAC National Accelerator LaboratoryMenlo ParkCA94025USA
| | - Maria R. Lukatskaya
- SSRL Materials Science DivisionSLAC National Accelerator LaboratoryMenlo ParkCA94025USA
- SLAC National Accelerator LaboratoryJoint Center for Energy Storage Research (JCESR)LemontIL60439USA
- Laboratory for Electrochemical Energy SystemsDepartment of Mechanical and Process EngineeringETH Zürich8092ZürichSwitzerland
| | - Christopher J. Takacs
- SSRL Materials Science DivisionSLAC National Accelerator LaboratoryMenlo ParkCA94025USA
- SLAC National Accelerator LaboratoryJoint Center for Energy Storage Research (JCESR)LemontIL60439USA
| | - Gang Wan
- SSRL Materials Science DivisionSLAC National Accelerator LaboratoryMenlo ParkCA94025USA
| | | | - Yuchi Tsao
- Department of ChemistryStanford UniversityStanfordUSA
| | - Jingbo Zhao
- Joint Center for Energy Storage ResearchLawrence Berkeley National LaboratoryBerkeleyCA94720USA
| | - Brett A. Helms
- Joint Center for Energy Storage ResearchLawrence Berkeley National LaboratoryBerkeleyCA94720USA
- The Molecular FoundryLawrence Berkeley National LaboratoryBerkeleyCA94720USA
| | - Kang Xu
- Energy Storage BranchSensor and Electron Devices DirectorateU.S. Army Research LaboratoryAdelphi20783USA
| | - Oleg Borodin
- Energy Storage BranchSensor and Electron Devices DirectorateU.S. Army Research LaboratoryAdelphi20783USA
| | | | - Michael F. Toney
- SSRL Materials Science DivisionSLAC National Accelerator LaboratoryMenlo ParkCA94025USA
- SLAC National Accelerator LaboratoryJoint Center for Energy Storage Research (JCESR)LemontIL60439USA
- Department of Chemical and Biological EngineeringUniversity of ColoradoBoulderCO80309USA
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Knudtzon MN, Blank DA. Photodetachment and Electron Dynamics in 1-Butyl-1-methyl-pyrrolidinium Dicyanamide. J Phys Chem B 2020; 124:9144-9153. [PMID: 32955885 DOI: 10.1021/acs.jpcb.0c06508] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ultrafast transient absorption spectrum of 1-butyl-1-methyl-pyrrolidinium dicyanamide, [Pyr1,4+][DCA-], was measured in the visible and near-infrared (IR) spectral regions. Excitation of the liquid at 4.6 eV created initially delocalized and highly reactive electrons that either geminately recombined (69%) or localized onto a cavity with a time constant of ∼300 fs. Electron localization was reflected in the evolution of the TA spectrum and the time-dependent loss of reactivity with a dichloromethane quencher. The delocalized initial state and spectrum of the free electrons were consistent with computational predictions by Xu and Margulis [ J. Phys. Chem. B, 2015, 119, 532-542] on excess electrons in [Pyr1,4+][DCA-]. The computational study considered two possible localization mechanisms for excess electrons, localization on ions, and localization on cavities. In the case of photogenerated electron-hole pairs, the results presented here demonstrate localization to cavities as the dominant channel. Following localization onto a cavity, the free electrons underwent solvation and loss of reactivity with the quencher with rates that slowed in time. The dynamics were similar to an analogous prior study on the related liquid [Pyr1,x+][NTf2-]. One significant difference was the larger yield of free electrons from photoexcitation of [Pyr1,4+][DCA-]. This was found to primarily reflect more efficient localization onto cavities rather than a slower geminate recombination rate.
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Affiliation(s)
- Meghan N Knudtzon
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - David A Blank
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
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Steinrück H, Cao C, Lukatskaya MR, Takacs CJ, Wan G, Mackanic DG, Tsao Y, Zhao J, Helms BA, Xu K, Borodin O, Wishart JF, Toney MF. Interfacial Speciation Determines Interfacial Chemistry: X‐ray‐Induced Lithium Fluoride Formation from Water‐in‐salt Electrolytes on Solid Surfaces. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202007745] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Hans‐Georg Steinrück
- SSRL Materials Science Division SLAC National Accelerator Laboratory Menlo Park CA 94025 USA
- SLAC National Accelerator Laboratory Joint Center for Energy Storage Research (JCESR) Lemont IL 60439 USA
- Department Chemie Universität Paderborn 33098 Paderborn Germany
| | - Chuntian Cao
- SSRL Materials Science Division SLAC National Accelerator Laboratory Menlo Park CA 94025 USA
| | - Maria R. Lukatskaya
- SSRL Materials Science Division SLAC National Accelerator Laboratory Menlo Park CA 94025 USA
- SLAC National Accelerator Laboratory Joint Center for Energy Storage Research (JCESR) Lemont IL 60439 USA
- Laboratory for Electrochemical Energy Systems Department of Mechanical and Process Engineering ETH Zürich 8092 Zürich Switzerland
| | - Christopher J. Takacs
- SSRL Materials Science Division SLAC National Accelerator Laboratory Menlo Park CA 94025 USA
- SLAC National Accelerator Laboratory Joint Center for Energy Storage Research (JCESR) Lemont IL 60439 USA
| | - Gang Wan
- SSRL Materials Science Division SLAC National Accelerator Laboratory Menlo Park CA 94025 USA
| | | | - Yuchi Tsao
- Department of Chemistry Stanford University Stanford USA
| | - Jingbo Zhao
- Joint Center for Energy Storage Research Lawrence Berkeley National Laboratory Berkeley CA 94720 USA
| | - Brett A. Helms
- Joint Center for Energy Storage Research Lawrence Berkeley National Laboratory Berkeley CA 94720 USA
- The Molecular Foundry Lawrence Berkeley National Laboratory Berkeley CA 94720 USA
| | - Kang Xu
- Energy Storage Branch Sensor and Electron Devices Directorate U.S. Army Research Laboratory Adelphi 20783 USA
| | - Oleg Borodin
- Energy Storage Branch Sensor and Electron Devices Directorate U.S. Army Research Laboratory Adelphi 20783 USA
| | - James F. Wishart
- Chemistry Division Brookhaven National Laboratory Upton NY 11973 USA
| | - Michael F. Toney
- SSRL Materials Science Division SLAC National Accelerator Laboratory Menlo Park CA 94025 USA
- SLAC National Accelerator Laboratory Joint Center for Energy Storage Research (JCESR) Lemont IL 60439 USA
- Department of Chemical and Biological Engineering University of Colorado Boulder CO 80309 USA
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Ye M, Iwata K. Ultrafast Electron Solvation in Room Temperature Ionic Liquid Observed by Femtosecond Time-resolved Near-IR Spectroscopy. CHEM LETT 2019. [DOI: 10.1246/cl.181043] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Manping Ye
- College of Optical and Electronic Technology, China Jiliang University, Hangzhou 310018, P. R. China
- Department of Chemistry, Faculty of Science, Gakushuin University, 1-5-1 Mejiro, Toshima-ku, Tokyo 171-8588, Japan
| | - Koichi Iwata
- Department of Chemistry, Faculty of Science, Gakushuin University, 1-5-1 Mejiro, Toshima-ku, Tokyo 171-8588, Japan
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Wu F, Xu C, Margulis CJ. Dynamics of an excess hole in the 1-methyl-1-butyl-pyrrolidinium dicyanamide ionic-liquid. J Chem Phys 2018; 148:193831. [DOI: 10.1063/1.5009940] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Fei Wu
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, USA
| | - Changhui Xu
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, USA
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Dhungana KB, Wu F, Margulis CJ. Excess Electron and Hole in 1-Benzylpyridinium-Based Ionic Liquids. J Phys Chem B 2017; 121:8809-8816. [DOI: 10.1021/acs.jpcb.7b07499] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kamal B. Dhungana
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - Fei Wu
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - Claudio J. Margulis
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
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Saenko EV, Lukianova MA, Shiryaeva ES, Takahashi K, Feldman VI. Radiation-induced intermediates in irradiated glassy ionic liquids at low temperature. Radiat Phys Chem Oxf Engl 1993 2016. [DOI: 10.1016/j.radphyschem.2015.11.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Musat RM, Kondoh T, Gohdo M, Yoshida Y, Takahashi K. Radiolytic yields of solvated electrons in ionic liquid and its solvation dynamics at low temperature. Radiat Phys Chem Oxf Engl 1993 2016. [DOI: 10.1016/j.radphyschem.2015.11.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Molins i Domenech F, Healy AT, Blank DA. Photodetachment, electron cooling, and recombination, in a series of neat aliphatic room temperature ionic liquids. J Chem Phys 2015; 143:064506. [DOI: 10.1063/1.4927915] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
| | - Andrew T. Healy
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - David A. Blank
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA
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