Three‐Phase Multiscale Modeling of a LiCoO2 Cathode: Combining the Advantages of FIB–SEM Imaging and X‐Ray Tomography |
| |
| Authors: | Lukas Zielke Tobias Hutzenlaub Dean R. Wheeler Chien‐Wei Chao Ingo Manke André Hilger Nils Paust Roland Zengerle Simon Thiele |
| |
| Affiliation: | 1. Laboratory for MEMS Applications, IMTEK Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany;2. HSG‐IMIT Institut für Mikro‐ und Informationstechnik, der Hahn‐Schickard‐Gesellschaft e.V., Freiburg, Germany;3. Department of Chemical Engineering, Brigham Young University, UT, USA;4. Helmholtz Zentrum Berlin, Berlin, Germany;5. FIT University of Freiburg, Freiburg, Germany |
| |
| Abstract: | LiCoO2 electrodes contain three phases, or domains, each having specific‐intended functions: ion‐conducting pore space, lithium‐ion‐reacting active material, and electron conducting carbon‐binder domain (CBD). Transport processes take place in all domains on different characteristic length scales: from the micrometer scale in the active material grains through to the nanopores in the carbon‐binder phase. Consequently, more than one imaging approach must be utilized to obtain a hierarchical geometric representation of the electrode. An approach incorporating information from the micro‐ and nanoscale to calculate 3D transport‐relevant properties in a large‐reconstructed active domain is presented. Advantages of focused ion beam/scanning electron microscopy imaging and X‐ray tomography combined by a spatial stochastic model, validated with an artificially produced reference structure are used. This novel approach leads to significantly different transport relevant properties compared with previous tomographic approaches: nanoporosity of the CBD leads to up to 42% additional contact area between active material and pore space and increases ionic conduction by a factor of up to 3.6. The results show that nanoporosity within the CBD cannot be neglected. |
| |
| Keywords: | batteries focused ion beam/scanning electron microscopy ionic conduction 3D modeling X‐ray tomography |
|
|
