Abstract: Lithium-ion batteries (LIBs) are the dominating energy storage technology for electric vehicles and portable electronic devices. Since the resources of raw materials for LIBs are limited and recycling technologies for LIBs are still under development, improvements in the long-term stability of LIBs are of paramount importance, and, in addition, would lead to a reduction in the levelized cost of storage (LCOS). A crucial limiting factor is the ageing of the solid electrolyte interphase (SEI) on the active material particles in the anode. Here, we demonstrate the potential of atom probe tomography for elucidating the complex mosaic-type structure of the SEI in a graphite composite anode. Our 3D reconstruction shows unseen details and reveals the existence of an apolar organic microphase pervading the SEI in its entire thickness. This finding is in stark contrast to the prevalent two-layer SEI model, in which organic compounds are the dominating species only in the outer SEI layer being in contact to the liquid electrolyte. The observed spatial arrangement of the apolar organic microphase promises a better understanding of the passivation capability of the SEI, which is necessary to expand battery lifetime.
TechnicalRemarks: List of used files
*.csv
composition_profiles.csv
The file contains the underlying data for the atomic percentage plots in Figure S5.
Listed are distance in z-direction and atomic percentages of Li, C, F, and O.
mass_spectrum.csv
contains the presented mass spectrum in Figure S1
detection_rate.csv
detection rate observed during the APT run used for Figure S2
voltage_history.csv
voltage observed during the APT run used for Figure S2
*.pos
file contains the reconstructed data for the APT run
*.rrng
contains the mass identification used in the reconstruction
*.rhit
contains the raw data for the APT run
