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Stabilization of Li-Rich Disordered Rocksalt Oxyfluoride Cathodes by Particle Surface Modification

Naylor, Andrew J.; Källquist, Ida; Peralta, David; Martin, Jean-Frederic; Boulineau, Adrien; Colin, Jean-François; Baur, Christian; Chable, Johann; Fichtner, Maximilian; Edström, Kristina; Hahlin, Maria; Brandell, Daniel

Abstract:
Promising theoretical capacities and high voltages are offered by Li-rich disordered rocksalt oxyfluoride materials as cathodes in lithium-ion batteries. However, as has been discovered for many other Li-rich materials, the oxyfluorides suffer from extensive surface degradation, leading to severe capacity fading. In the case of Li$_{2}$VO$_{2}$F, we have previously determined this to be a result of detrimental reactions between an unstable surface layer and the organic electrolyte. Herein, we present the protection of Li$_{2}$VO$_{2}$F particles with AlF$_{3}$ surface modification, resulting in a much-enhanced capacity retention over 50 cycles. While the specific capacity for the untreated material drops below 100 mA h g$^{-1}$ after only 50 cycles, the treated materials retain almost 200 mA h g$^{-1}$. Photoelectron spectroscopy depth profiling confirms the stabilization of the active material surface by the surface modification and reveals its suppression of electrolyte decomposition.

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Verlagsausgabe §
DOI: 10.5445/IR/1000122133
Veröffentlicht am 27.07.2020
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Nanotechnologie (INT)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 06.2020
Sprache Englisch
Identifikator ISSN: 2574-0962, 2574-0962
KITopen-ID: 1000122133
HGF-Programm 37.01.01 (POF III, LK 01)
Fundamentals and Materials
Erschienen in ACS applied energy materials
Band 3
Heft 6
Seiten 5937–5948
Vorab online veröffentlicht am 29.05.2020
Nachgewiesen in Web of Science
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