Moroni Riko, Börner Markus, Zielke Lukas, Schroeder Melanie, Nowak Sascha, Winter Martin, Manke Ingo, Zengerle Roland, Thiele Simon
Laboratory for MEMS Applications, IMTEK Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany.
MEET Battery Research Center, Institute of Physical Chemistry, University of Münster, Corrensstraße 46, 48149 Münster, Germany.
Sci Rep. 2016 Jul 26;6:30109. doi: 10.1038/srep30109.
Focused ion beam/scanning electron microscopy tomography (FIB/SEMt) and synchrotron X-ray tomography (Xt) are used to investigate the same lithium manganese oxide composite cathode at the same specific spot. This correlative approach allows the investigation of three central issues in the tomographic analysis of composite battery electrodes: (i) Validation of state-of-the-art binary active material (AM) segmentation: Although threshold segmentation by standard algorithms leads to very good segmentation results, limited Xt resolution results in an AM underestimation of 6 vol% and severe overestimation of AM connectivity. (ii) Carbon binder domain (CBD) segmentation in Xt data: While threshold segmentation cannot be applied for this purpose, a suitable classification method is introduced. Based on correlative tomography, it allows for reliable ternary segmentation of Xt data into the pore space, CBD, and AM. (iii) Pore space analysis in the micrometer regime: This segmentation technique is applied to an Xt reconstruction with several hundred microns edge length, thus validating the segmentation of pores within the micrometer regime for the first time. The analyzed cathode volume exhibits a bimodal pore size distribution in the ranges between 0-1 μm and 1-12 μm. These ranges can be attributed to different pore formation mechanisms.
聚焦离子束/扫描电子显微镜断层扫描（FIB/SEMt）和同步加速器X射线断层扫描（Xt）用于在同一特定位置研究相同的锂锰氧化物复合阴极。这种关联方法允许研究复合电池电极断层分析中的三个核心问题：（i）验证最新的二元活性材料（AM）分割：尽管标准算法的阈值分割导致非常好的分割结果，但有限的Xt分辨率导致AM低估6体积%，并且严重高估AM连通性。（ii）Xt数据中的碳粘结剂域（CBD）分割：虽然阈值分割不能用于此目的，但引入了一种合适的分类方法。基于关联断层扫描，它允许将Xt数据可靠地三元分割为孔隙空间、CBD和AM。（iii）微米尺度下的孔隙空间分析：这种分割技术应用于边长为几百微米的Xt重建，从而首次验证了微米尺度内孔隙的分割。分析的阴极体积在0-1μm和1-12μm范围内呈现双峰孔径分布。这些范围可归因于不同的孔隙形成机制。
