Rajendra Thushananth, Mistry Aashutosh N, Patel Prehit, Ausderau Logan J, Xiao Xianghui, Mukherjee Partha P, Nelson George J
Department of Mechanical & Aerospace Engineering , The University of Alabama in Huntsville , Huntsville , Alabama 35899 , United States.
School of Mechanical Engineering , Purdue University , West Lafayette , Indiana 47907 , United States.
ACS Appl Mater Interfaces. 2019 Jun 5;11(22):19933-19942. doi: 10.1021/acsami.8b22758. Epub 2019 May 24.
The charge/discharge capabilities of Li-ion cathodes are influenced by the meso-scale geometry, transport properties, and morphological parameters of the constituent phases in the cathode: active material, binder, conductive additive, and pore. Electrode processing influences the structure and attendant properties of these constituents. Thus, performance of the battery can be enhanced by correlating various electrode processing techniques with the charge/discharge behavior in the lithium-ion cathodes. X-ray microtomography was used to image samples obtained from pristine Li(NiMnCo)O (NMC) cathodes subjected to distinct processing approaches. Two sample preparation approaches were applied to the samples prior to microtomography. Casting the samples in epoxy yielded only the cathode active material domain. Encapsulating the sample with Kapton tape yielded phase contrast data that permitted segmentation of the active material and combined carbon/binder and pore regions. Geometrical and morphological details of the active material and the secondary phases were characterized and compared between the varied processing approaches. Calendered and ball-milled samples exhibited distinct differences in both geometry and morphology. Drying modes demonstrated variation in the distribution of the secondary and pore phases. Applying phase contrast capabilities, the processing-morphology relationship can be better understood to enhance overall battery performance across multiple scales.
锂离子阴极的充放电能力受阴极中各组成相的介观尺度几何结构、传输特性和形态参数的影响，这些组成相包括活性材料、粘结剂、导电添加剂和孔隙。电极加工会影响这些成分的结构及相关性能。因此，通过将各种电极加工技术与锂离子阴极的充放电行为相关联，可以提高电池的性能。利用X射线显微断层成像技术对通过不同加工方法处理的原始Li（NiMnCo）O（NMC）阴极获得的样品进行成像。在进行显微断层成像之前，对样品应用了两种样品制备方法。将样品浇铸在环氧树脂中只能得到阴极活性材料区域。用Kapton胶带封装样品可得到相衬数据，从而能够区分活性材料以及碳/粘结剂和孔隙区域的组合。对不同加工方法下活性材料和第二相的几何和形态细节进行了表征和比较。压延和球磨样品在几何结构和形态上均表现出明显差异。干燥方式表明第二相和孔隙相的分布存在差异。应用相衬能力，可以更好地理解加工与形态之间的关系，从而在多个尺度上提高电池的整体性能。
