Electric Potential Gradient at the Buried Interface between Lithium-Ion Battery Electrodes and the SEI Observed Using Photoelectron Spectroscopy.
The buried interface between the bulk electrode material and the solid electrolyte interphase (SEI) in cycled Li-ion battery anodes is suggested to incorporate an electric potential gradient. This suggestion is based on photoelectron spectroscopy (PES) results from different anode materials that all show relative binding energy shifts between the components of the SEI and the active anode. Implications of this electric potential gradient on binding energy reference points in PES as well as on charge-transfer kinetics in Li-ion batteries are discussed. Specifically, we show that the separation of surface layer and bulk material spectral contributions (depth profiling) is crucial for consistent data interpretation. We conclude that previous interpretations of lithiation as cause for changes in PES spectra may need to be revised.
Department of Chemistry - Ångström Laboratory, Uppsala University , Box 538, SE 751 21 Uppsala, Sweden.
Julia
J
Maibach
Department of Chemistry - Ångström Laboratory, Uppsala University , Box 538, SE 751 21 Uppsala, Sweden.
Fredrik
F
Lindgren
Department of Chemistry - Ångström Laboratory, Uppsala University , Box 538, SE 751 21 Uppsala, Sweden.
Henrik
H
Eriksson
Department of Chemistry - Ångström Laboratory, Uppsala University , Box 538, SE 751 21 Uppsala, Sweden.
Kristina
K
Edström
Department of Physics and Astronomy, Uppsala University , Box 516, SE 751 21 Uppsala, Sweden.
Maria
M
Hahlin