Analysis of the 3D microstructure of experimental cathode films for lithium‐ion batteries under increasing compaction

Abstract

It is well known that the microstructure of electrodes in lithium-ion batteries has an immense impact on their overall performance. The manufacturing of the batteries includes the so-called calendering, where the electrodes are compressed with a certain pressure, which is called compaction load. This process step mainly determines the resulting morphology of the electrode and thus the properties of the battery. Therefore, eight cathodes with different compaction loads were manufactured and imaged by synchrotron tomography, which leads to 3D images containing detailed information about the inner structure of the cathode. This image data allows an extensive analysis of the 3D cathode microstructure with respect to increasing compaction. In order to quantify the microstructural changes we use several characteristics describing diverse properties of the morphology. Furthermore, the 3D image data can be used for the computation of characteristics which can not be determined by experiments. Therefore, 3D image data allows us to understand how the microstructure of cathodes is influenced by the compaction load. Finally, we are able to predict the distribution of a certain characteristic for arbitrary compaction loads. This information is valuable with regard to the development of improved lithium-ion batteries.