• Zielke, L.; Hutzenlaub, T.; Wheeler, D.R.; Chao, C.W.; Manke, I.; Hilger, A.; Paust, N.; Zengerle, R.; Thiele, S.: Three-Phase Multiscale Modeling of a LiCoO2 Cathode: Combining the Advantages of FIB–SEM Imaging and X-Ray Tomography. Advanced Energy Materials 5 (2015), p. 1401612/1-8

10.1002/aenm.201401612

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. Three-Phase Multiscale Modeling of a LiCoO2 Cathode: Combining the Advantages of FIB–SEM Imaging and X-Ray Tomography. Available from: https://www.researchgate.net/publication/268579630_Three-Phase_Multiscale_Modeling_of_a_LiCoO2_Cathode_Combining_the_Advantages_of_FIBSEM_Imaging_and_X-Ray_Tomography [accessed Dec 11, 2015].