Abstract
The surface chemistry of aged Li4Ti5O12 and LiFePO4 electrodes that have been cycled in a full cell configuration are examined using nuclear magnetic resonance. The failure mechanism of such cells has been previously identified to be an electrode capacity slippage process caused by the loss of charge carriers: electrons or lithium ions. The electrode-electrolyte interphase is quantitatively analyzed after cycling thanks to a calibration of NMR spectra. LiF is detected at both electrodes: about 1.2 μmol mg-1 at the Li4Ti5O12-based electrode and about 0.35 μmol mg-1 at the LiFePO4-based electrode, and it is the main component amongst lithiated species. By comparison with gravimetric studies, LiF cannot be the only component of the interphase. From a correlation between the amount of detected LiF and the electrode capacity slippage of the battery, different reaction paths are proposed at each electrode, involving either moisture-driven catalysis or reductive process that consumes a quantity of charge from the electrode.
Original language | English |
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Pages (from-to) | 391-395 |
Number of pages | 5 |
Journal | Electrochimica Acta |
Volume | 155 |
Early online date | 24 Dec 2014 |
DOIs | |
Publication status | Published - 10 Feb 2015 |
Funding
This work was supported by the project PERLE2 of the Région Pays-de-la-Loire (France) and by CEA/LITEN.
Keywords
- Li-ion battery
- LiF
- NMR
- parasitic reactions
- surface
ASJC Scopus subject areas
- General Chemical Engineering
- Electrochemistry