We present multiscale techniques for 3D imaging of the inner structure of energy materials with the goal to provide structural data for microstructure modeling and virtual materials design.
3D imaging is an important tool for the development of energy materials because it allows us to study the inner structure and morphology of energy materials. This is essential for the understanding and quantifying of structure-property relationships. In order to provide a high energy density, the battery electrodes must feature a complex hierarchical structure that ranges from the millimeter down to the nanometer scale. We investigated lithium-nickel-manganese-cobalt-oxide (NMC) electrodes with a focus on the highly structured NMC particles and their surrounding support material. First the microstructure of the NMC electrode was studied by means of 3D tomography using synchrotron radiation at BESSY II, resulting in a broad overview and understanding of the spatial distribution and shape of NMC particles on the micrometer scale. Additionally we could acquire a reconstruction of the surrounding support material in the electrode. Secondly, 3D focused-ion-beam (FIB) measurements were conducted, allowing a detailed insight into the nanopores of the NMC particles and their interconnections. To gain enough information about the local variability of the nanostructures large scale 2D areas of the NMC particles have been prepared by means of mechanical polishing or argon ion milling. The slices have then been measured with a scanning electron microscope (SEM). The combination of the 2D analysis of up to 1000 particle cross sections with the 3D FIB datasets and the 3D synchrotron datasets allows for a detailed analysis of the of the 3D microstructure of the electrodes (see Figure 1).
Electrodes with different production parameters, like sinter temperature and particle size distribution, have been measured as described above with the aim of optimization and gaining a deeper understanding of the underlying production processes.
|Category||Short file description||File description||File Size|
|Presentation||Figure 1||Figure 1: Combination of different measurement techniques aiming at studying the interior structure and morphology of battery cathodes. Left: 3D synchrotron dataset; Center: 2D SEM data; Right: 3D FIB-SEM dataset.||1 MB||Download|