Publication
Article Metrics
Citations
Online attention
Improving capacity retention of Li2VO2F Li-rich cathodes with film-forming additives
Authors:
Ida
Kallquist
(Uppsala University)
,
Jean-frederic
Martin
(CEA-LITEN)
,
Andrew
Naylor
(Uppsala University)
,
Christian
Baur
(Helmholtz Institute Ulm)
,
Maximilian
Fichtner
(Helmholtz Institute Ulm; Karlsruhe Institute of Technology)
,
Jean-francois
Colin
(CEA-LITEN)
,
Daniel
Brandell
(Uppsala University)
,
Kristina
Edstrom
(Uppsala University)
,
Maria
Hahlin
(Uppsala University)
Co-authored by industrial partner:
No
Type:
Journal Paper
Journal:
The Journal Of Physical Chemistry C
State:
Published (Approved)
Published:
May 2020
Diamond Proposal Number(s):
20870
Abstract: Li-rich disordered rock-salt structures have due to their high theoretical capacity gained large attention as a promising class of cathode materials for battery applications. However, the cycling stability of these materials have so far been less satisfactory. Here, we present three different film forming electrolyte additives; lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxalato)borate (LiODFB), and glycolide, which all improve the cycling performance of the high capacity Li-rich disordered rock-salt material Li2VO2F. The best performing additive, LiODFB, show a 12.5% increase of capacity retention after 20 cycles. The improved cycling performance is explained by the formation of a more robust cathode interphase on the electrode surface. Photoelectron spectroscopy is used to show that the surface layer is created from oxidation of the electrolyte salt and additive co-salts. This passivating layer can mitigate oxidation and following degradation of the active material, and thus a higher degree of redox active vanadium can be maintained after 20 cycles.
Subject Areas:
Chemistry,
Materials,
Energy
Instruments:
I09-Surface and Interface Structural Analysis