Regensburg 2025 – scientific programme
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 10: Materials for the Storage and Conversion of Energy (joint session MM/KFM)
KFM 10.2: Talk
Tuesday, March 18, 2025, 14:15–14:30, H22
Electro-chemo-mechanical behavior of a layered cathode material upon cycling — •Robert Löser1, Yug Joshi2, Roham Talei1, and Guido Schmitz1 — 1University of Stuttgart, Stuttgart, Germany — 2Max-Planck-Institut für Nachhaltige Materialien GmbH, Düsseldorf, Germany
The mechanical properties of lithium-ion cathode materials play a critical role in determining battery performance such as cycle life, durability, and safety, especially when the battery is under external pressure which is typical for all-solid-state batteries. This research investigates LiCoO2 (LCO), a prevalent hexagonal layer-structured cathode material, and explores its mechanical responses during de-/lithiation using sputter-deposited thin films and nanoindentation. The values of the experimental Young*s modulus in pure (101) and (003) lattice orientations are quantified to 337.1 * 8.7 GPa and 267.9 * 7.2 GPa, respectively, in the fully lithiated state. Furthermore, a substantial texture-dependent decrease in Young*s modulus upon lithium deintercalation is demonstrated, probably due to modification of the bonding interactions between the cobalt oxide layers. Delithiation also elevates the relative contribution of plastic deformation, indicating that dislocation glide becomes easier in deintercalated states. By extensive cycling, the Young*s modulus in higher lithiated charge-states decreases considerably which is most-likely due to irreversibility of phase transitions. The work provides valuable insight on the dynamic changes of the mechanical properties during electrochemical cycling of LiCoO2, which paves the way for all other layered cathode materials.
Keywords: Lithium cobalt oxide; Mechanics; Electrochemical fatigue; Young modulus; Nano-indentation