Interfacial Speciation Determines Interfacial Chemistry: X-ray-Induced Lithium Fluoride Formation from Water-in-salt Electrolytes on Solid Surfaces.

Autor: Steinrück HG; 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., Cao C; SSRL Materials Science Division, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA., Lukatskaya MR; 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., Takacs CJ; 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., Wan G; SSRL Materials Science Division, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA., Mackanic DG; Department of Chemical Engineering, Stanford University, Stanford, USA., Tsao Y; Department of Chemistry, Stanford University, Stanford, USA., Zhao J; Joint Center for Energy Storage Research, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA., Helms BA; 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., Xu K; Energy Storage Branch, Sensor and Electron Devices Directorate, U.S. Army Research Laboratory, Adelphi, 20783, USA., Borodin O; Energy Storage Branch, Sensor and Electron Devices Directorate, U.S. Army Research Laboratory, Adelphi, 20783, USA., Wishart JF; Chemistry Division, Brookhaven National Laboratory, Upton, NY, 11973, USA., Toney MF; 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.
Jazyk: angličtina
Zdroj: Angewandte Chemie (International ed. in English) [Angew Chem Int Ed Engl] 2020 Dec 14; Vol. 59 (51), pp. 23180-23187. Date of Electronic Publication: 2020 Oct 09.
DOI: 10.1002/anie.202007745
Abstrakt: 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/H 2 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.
(© 2020 The Authors. Published by Wiley-VCH GmbH.)
Databáze: MEDLINE
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