Calendering is a crucial manufacturing process in the optimization of battery performance and lifetime due to its significant effect on the 3D electrode microstructure. By conducting an in situ calendering experiment on lithium-ion battery cathodes using X-ray nano-computed tomography, here we show that the electrodes composed of large particles with a broad size distribution experience heterogeneous microstructural self-arrangement. At high C-rates, the performance is predominantly restricted by sluggish solid-state diffusion, which is exacerbated by calendering due to the increased microstructural and lithiation heterogeneity, leading to active material underutilization. In contrast, electrodes consisting of small particles are structurally stable with more homogeneous deformation and a lower tortuosity, showing a much higher rated capacity that is less sensitive to calendering densification. Finally, the dependence of performance on the dual variation of both porosity and electrode thickness is investigated to provide new insights into the microstructural optimization for different applications in electrode manufacturing.

压延由于其对3D电极微结构的显着影响，在优化电池性能和使用寿命方面是至关重要的制造过程。通过现场进行使用X射线纳米计算机断层扫描技术对锂离子电池阴极进行压延实验，在此我们发现由具有宽尺寸分布的大颗粒组成的电极经历了异质的微观结构自排列。在高C速率下，性能主要受缓慢的固态扩散限制，固态扩散由于微结构和锂化异质性的增加而被压延加重，导致活性材料利用率不足。相反，由小颗粒组成的电极在结构上稳定，变形更均匀，弯曲度更低，显示出更高的额定容量，对压延致密化不那么敏感。最后，