Microstructural feature analysis of commercial Li-ion battery cathodes by focused ion beam tomography
Microstructural feature analysis of commercial Li-ion battery cathodes by focused ion beam tomography
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DOI：
10.1016/j.jpowsour.2019.04.019
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发表时间：
2019-07-01
影响因子：
9.2
通讯作者：
Ivers-Tiffee, E.
中科院分区：
文献类型：
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作者：
Almar, L.;Joos, J.;Ivers-Tiffee, E.
从两个高功率和两个高能锂离子电池消费电池中提取四个正极，然后通过聚焦离子束扫描电子显微镜 (FIB-SEM) 断层扫描进行分析。使用适当的 3D 分析技术，通过体积分数、表面积、粒度分布和弯曲度对活性材料相、炭黑粘合剂相和孔隙相进行定量评估。活性材料相由 LiCoO2（Sanyo 1500 mA h）或 LiNiCoAlO2（Sony 2600 mA h）或两种 LiNiCoAl2-LiCoO2 混合物之一（Kokam 高功率 350 mA h 和高能 560 mA h）组成。特别强调亚微米尺寸（但高度团聚）炭黑粘合剂相的三维分布。使用双组分有机硅树脂进行真空渗透，在炭黑粘合剂和孔相之间产生灰度对比，用于在 30 至 50 nm 的体素尺寸下进行轮廓描述。这项研究阐明了高能和高功率应用的阴极微观结构特征，并提供了具有不同化学成分的商业电极的完整参数集。这些信息可以被科学界用作模拟和模型中的输入参数，填补实验和模拟领域之间的空白。
Four positive electrodes are extracted from two high-power and two high-energy Li-ion battery consumer cells, and then analyzed by focused ion beam-scanning electron microscopy (FIB-SEM) tomography. The active material phase, carbon black-binder phase and pore phase are quantitatively evaluated using adequate 3D analysis techniques by their volume fractions, surface areas, particle size distributions and tortuosities. The active material phase is composed of LiCoO2 (Sanyo 1500 mA h), or LiNiCoAlO2 (Sony 2600 mA h) or one of two LiNiCoAl2-LiCoO2 blends (Kokam high-power 350 mA h and high-energy 560 mA h). Special emphasis was put on the three-dimensional distribution of the submicron-sized (yet highly agglomerated) carbon black-binder phase. Vacuum infiltration with a two-component silicone resin gave greyscale contrast between the carbon black-binder and pore phases for contour description at voxel sizes from 30 to 50 nm. This study elucidates the cathode microstructural features for high-energy and high-power application and provides a complete parameter set of commercial electrodes with differing chemical composition. This information can be used by the scientific community as input parameters in simulations and models, filling the gap between the experimental and the simulation fields.