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Download fileCan an Inorganic Coating Serve as Stable SEI for Aqueous Superconcentrated Electrolytes?
journal contribution
posted on 2021-06-28, 18:05 authored by Léa Droguet, Gustavo M. Hobold, Marie Francine Lagadec, Rui Guo, Christophe Lethien, Maxime Hallot, Olivier Fontaine, Jean-Marie Tarascon, Betar M. Gallant, Alexis GrimaudDeveloping
a stable, conformal solid electrolyte interphase (SEI)
for aqueous-based Li-ion batteries has been a long-awaited dream to
support the development of nontoxic and eco-friendly energy storage
technologies. Toward that goal, aqueous superconcentrated electrolytes
were recently introduced as their unique solvation structure allows
for forming a LiF-rich SEI layer at the negative electrode, imparting
the stability to the interface. However, the intrinsic stability of
such LiF-rich SEI was never measured, despite growing evidence of
poor passivation properties and water reduction upon operation. In
this work, LiF conformal layers were coated onto lithium electrodes,
and their reactivity toward superconcentrated aqueous electrolytes
was studied by combining solubility measurements, in situ microscopy, and gas chromatography. We demonstrate that the use
of superconcentrated electrolytes drastically reduces the solubility
of LiF. However, such layer is intrinsically unstable in aqueous environments,
but stable in organic electrolytes, owing to the absence of self-passivation.
Comparing different interfaces, we conclude that an artificial SEI
made of an inorganic coating is not suitable for preventing water
reactivity in aqueous systems.
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Keywords
solubility measurementswater reactivityInorganic Coatingsolvation structureelectrolyte interphaseAqueous Superconcentrated Electrolytesstabilitypassivation propertiesLiF-rich SEIaqueous-based Li-ion batteriesgas chromatographyinterfacelithium electrodeseco-friendly energy storage technol...water reductionStable SEILiF-rich SEI layerLiF conformal layers