Li Battery Material Behavior Studied in situ in Electron Microscopes
Postdoc Christian Proff (MSD), will present "Li Battery Material Behavior Studied in situ in Electron Microscopes." Bring your lunch. Cookies will be provided.
Li battery materials are usually studied with methods providing averaged properties of the materials of interest like x-ray diffraction and coin cell cycling. These methods provide a good measure to evaluate material behavior averaged over macroscopic volumes and are able to show the change in important parameters with repeated charge/discharge cycles.
However, in electron microscopes it is possible to image the processes taking place (in situ) and to analyze ex-situ the microstructure and correlate it with the observed performance. Some of these changes are difficult to identify with non-imaging techniques Using the example of in situ and snapshot mode experiments in the scanning electron microscope (SEM) on Li battery cathode particles, which observations can be made and what limitations apply.
Details on different transition metal oxide-based materials for the cathode side of the cell have been investigated with different approaches:
- In situ continuous observation
- Snapshot mode
Focused ion beam milling is used for the observation of the microstructure. Among other features intergranular cracking of the particles of certain materials could be observed, developing over the number of cycles, which can result in insufficient electrical contact after extended cracking. The presentation will highlight the insights offered by these approaches.