Berlin 2024 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 5: Materials for Storage and Conversion of Energy I

MM 5.4: Talk

Monday, March 18, 2024, 11:00–11:15, C 264

Mechanical testing of LiCoO2 battery electrode and effect of de-/lithiation — •Robert Löser, Yug Joshi, and Guido Schmitz — Institut für Materialwissenschaft, Universität Stuttgart, Deutschland

The mechanical characteristics of lithium-ion cathode materials play a crucial role in determining key battery performance such as durability, cycle life, and safety. This study focuses on LiCoO2 (LCO), a widely used layered-structured cathode material for lithium-ion batteries, and investigates its mechanical properties during delithiation using sputtered thin films and nanoindentation techniques. The research reveals a significant decrease in Young's modulus from 275.9GPa to 243.4GPa upon lithium-ion deintercalation, attributed to alterations in bonding interactions. After subjecting the sample to extensive cycling, the decline in Young's modulus after the delithiation is reduced to 4.3% with a Young's modulus for the fully lithiated state of 255.5GPa. Additionally, this investigation identifies a linear increase in the proportion of elastic deformation with decreasing lithium content. Furthermore, the experiment in comparison to finite element method (FEM) simulations suggest the propagation of a Li0.5CoO2 phase from the top of the layer during delithiation. This work sheds light on the dynamic changes in mechanical properties of LCO, providing valuable insights for the design and optimization of lithium-ion batteries.

Keywords: Cathode materials; Lithium ion battery; Lithium cobalt oxide; Mechanical properties; Electrochemical delithiation