A Model for Investigating Sources of Li-Ion Battery Electrode Heterogeneity: Part II. Active Material Size, Shape, Orientation, and Stiffness

This work is the extension of our previous paper [Nikpour et al., J. Electrochem. Soc. 168, 060547, (2021)] which introduced the multi-phase smoothed particle (MPSP) model. This model was used to simulate the evolution of the microstructure during the drying and calendering manufacturing processes of four different electrodes. The MPSP model uses particle properties to predict overall film properties such as conductivities and elastic moduli and is validated by multiple experiments. In this work, the model is used to investigate the effects of active material particle size, shape, orientation, and stiffness on graphitic anodes. The model predicts that smaller active particles produce higher calendered film density, electronic conductivity, MacMullin number, and Young's modulus, as compared to larger active particles. Rod-shaped active materials have greater ionic transport and lower electronic transport compared to the disk and sphere shapes, which have similar transport properties. During calendering, disk-shaped particles tend to be oriented horizontally, which decreases through-plane ionic transport. Increasing the stiffness of the active material increases film porosity and composite Young's modulus, while lowering electronic transport and increasing ionic transport.

Automated summary

This study investigates the effects of active material particle size, shape, orientation, and stiffness on the performance of graphitic anodes using the MPSP model. It found that smaller active particles result in higher density films with better conductivity and elastic modulus. Additionally, disk-shaped particles tend to be horizontally oriented during calendering, reducing through-plane ionic transport, and increasing stiffness leads to higher porosity in the film.