1. Electrochemical impedance spectroscopy of Li-ion negative electrodes based on titanium oxyfluoride and titanium trifluoride.
- Author
-
Lozhkina, Darina A., Grushina, Anna A., Parfeneva, Alesya V., Astrova, Ekaterina V., Ulin, Vladimir P., and Rumyantsev, Aleksander M.
- Subjects
- *
NEGATIVE electrode , *IMPEDANCE spectroscopy , *TITANIUM oxidation , *TITANIUM , *IONIC conductivity , *KIRKENDALL effect , *CHARGE transfer , *LITHIUM ions - Abstract
The processes of lithium insertion into TiOF 2 and TiF 3 electrodes were studied using electrochemical impedance spectroscopy. The measurements were carried out at different degrees of lithiation during the first two charge/discharge cycles. Electrical equivalent circuits were proposed to model the resulting impedance spectra. They reflect the processes of Li+ migration through SEI, lithium ion insertion/extraction stages with the change of titanium oxidation degree and lithium ion diffusion in the material volume. A comparative evaluation of kinetic parameters of TiF 3 and TiOF 2 electrodes depending on the degree of lithiation was carried out for the first time. It is shown that the main process of SEI formation takes place at the first cycle. SEI has a lower impedance value on TiF 3 electrodes. The concentration dependence of the charge transfer resistance and diffusion coefficient for TiF 3 and TiOF 2 materials is observed: with increasing lithium content the interfacial charge transfer resistance decreases and the Li+ diffusion coefficient increases. The concentration dependences of these parameters for TiOF 2 electrodes are more pronounced. • The kinetic parameters of TiOF 2 and TiF 3 electrodes was investigated by EIS method. • There is a difference in the R SEI , charge transfer and D Li+ for TiF 3 and TiOF 2. • The electronic and ionic conductivity of compounds influence the kinetic parameters. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF