In situ XANES and EXAFS Analysis of Redox Active Fe Center Ionic Liquids
Abstract
We apply in situ X-Ray Absorption Near Edge Spectroscopy (XANES) and Extended X-Ray Absorption Fine Structure (EXAFS) techniques to a metal center ionic liquid undergoing oxidation and reduction in a three electrode spectroscopic cell. Furthermore, the determination of the extent of reduction under negative bias on the working electrode and the extent of oxidation are determined after pulse voltammetry to quiescence. While the ionic liquid undergoes full oxidation, it undergoes only partial reduction, likely due to transport issues on the timescale of the experiment. Nearest neighbor Fe-O distances in the fully oxidized state match well to expected values for similarly coordinated solids, but reduction does not result in an extension of the Fe-O bond length, as would be expected from comparisons to the solid phase. Instead, little change in bond length is observed. Finally, we suggest that this may be due to a more complex interaction between the monodentate ligands of the metal center anion and the surrounding charge cloud, rather than straightforward electrostatics between the metal center and the nearest neighbor grouping.
- Authors:
-
[1];
- Joint Center for Energy Storage Reseach, Albuquerque, NM (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Power Sources Technology Group
- Univ. of Maine, Orono, ME (United States). Dept. of Physics and Astronomy
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Power Sources Technology Group
- Publication Date:
- Research Org.:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Electricity (OE)
- OSTI Identifier:
- 1338380
- Alternate Identifier(s):
- OSTI ID: 1359034
- Report Number(s):
- SAND2016-12355J
Journal ID: ISSN 0013-4686; 649726
- Grant/Contract Number:
- AC04-94AL85000; AC02-98CH10886
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Electrochimica Acta
- Additional Journal Information:
- Journal Volume: 185; Journal Issue: C; Journal ID: ISSN 0013-4686
- Publisher:
- Elsevier
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 25 ENERGY STORAGE; Electrochemistry; in situ XANES; in situ EXAFS; Redox active Ionic Liquids; Flow Batteries
Citation Formats
Apblett, Christopher A., Stewart, David M., Fryer, Robert T., Sell, Julia C., Pratt, Harry D. III, Anderson, Travis M., and Meulenberg, Robert W. In situ XANES and EXAFS Analysis of Redox Active Fe Center Ionic Liquids. United States: N. p., 2015.
Web. doi:10.1016/j.electacta.2015.09.093.
Apblett, Christopher A., Stewart, David M., Fryer, Robert T., Sell, Julia C., Pratt, Harry D. III, Anderson, Travis M., & Meulenberg, Robert W. In situ XANES and EXAFS Analysis of Redox Active Fe Center Ionic Liquids. United States. https://doi.org/10.1016/j.electacta.2015.09.093
Apblett, Christopher A., Stewart, David M., Fryer, Robert T., Sell, Julia C., Pratt, Harry D. III, Anderson, Travis M., and Meulenberg, Robert W. Fri .
"In situ XANES and EXAFS Analysis of Redox Active Fe Center Ionic Liquids". United States. https://doi.org/10.1016/j.electacta.2015.09.093. https://www.osti.gov/servlets/purl/1338380.
@article{osti_1338380,
title = {In situ XANES and EXAFS Analysis of Redox Active Fe Center Ionic Liquids},
author = {Apblett, Christopher A. and Stewart, David M. and Fryer, Robert T. and Sell, Julia C. and Pratt, Harry D. III and Anderson, Travis M. and Meulenberg, Robert W.},
abstractNote = {We apply in situ X-Ray Absorption Near Edge Spectroscopy (XANES) and Extended X-Ray Absorption Fine Structure (EXAFS) techniques to a metal center ionic liquid undergoing oxidation and reduction in a three electrode spectroscopic cell. Furthermore, the determination of the extent of reduction under negative bias on the working electrode and the extent of oxidation are determined after pulse voltammetry to quiescence. While the ionic liquid undergoes full oxidation, it undergoes only partial reduction, likely due to transport issues on the timescale of the experiment. Nearest neighbor Fe-O distances in the fully oxidized state match well to expected values for similarly coordinated solids, but reduction does not result in an extension of the Fe-O bond length, as would be expected from comparisons to the solid phase. Instead, little change in bond length is observed. Finally, we suggest that this may be due to a more complex interaction between the monodentate ligands of the metal center anion and the surrounding charge cloud, rather than straightforward electrostatics between the metal center and the nearest neighbor grouping.},
doi = {10.1016/j.electacta.2015.09.093},
journal = {Electrochimica Acta},
number = C,
volume = 185,
place = {United States},
year = {Fri Oct 23 00:00:00 EDT 2015},
month = {Fri Oct 23 00:00:00 EDT 2015}
}
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