Possibilities and limitations of tomography methods for the quantification of lithium-ion battery cathode microstructures
The microstructure of Lithium ion batteries electrodes strongly influences their performance. Hence, a profound knowledge of the complex structure is the key to fully understand and optimize the electrode performance. To analyze and quantify electrode structures, tomography methods like X-ray tomography or focused ion beam-secondary electron microscopy are typically used. While each method has advantages and disadvantages, understanding the complex morphology of electrodes requires a complementary, multi-scale 3D approach.
In this work, the possibilities and limitations for both 3D techniques, X-ray and FIB-SEM tomography, are studied using the example of a LiNiCoAlO2-LiCoO2 blend cathode from a commercial cell. The same cathode sample was analyzed with both techniques and moreover with different devices to allow a comparison of the obtained data and the microstructure parameters calculated from them. Therefore, parameters like the material fractions, porosity, surface area and tortuosity are calculated from the different data sets and the results are compared and discussed.