Characterization of the grain boundary strength of polycrystalline NMC811 using in situ micro tensile tests
Year: 2026
Type: article
Abstract: (NMC) is one of the most relevant lithium-ion battery cathode materials. In this study, micromechanical tests were used to examine the fracture behavior of (NMC811) secondary particles. Furthermore, the grain boundary strength was measured and the grain boundary stiffness was estimated to 521 GPa µm -1 . Using an optimized push-to-pull sample geometry produced by focused ion beam (FIB) technology and measuring the displacement through digital image correlation (DIC), micro tensile tests were performed and validated against nanoindentation. A Weibull distribution characteristic tensile strength of 745 MPa followed by a brittle fracture behavior was measured. The fracture surface was examined and showed an intercrystalline fracture. Through electron backscatter diffraction (EBSD) analysis, less frequently occurring transcrystalline fracture was detected. Scanning transmission electron microscopy (STEM) showed a slight increase in dislocation density within the testing section in comparison to reference positions. The results can be used for a more detailed understanding of the mechanical degradation during the cycling of batteries as well as for building accurate simulation models.
Source: Journal of Power Sources
Institution: RWTH Aachen University
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,230
OpenAlex ID: W7160649750