Effects of three-dimensional cathode microstructure on the performance of lithium-ion battery cathodes

This paper develops a computational model that resolves the complex three-dimensional microstructure of Li-ion battery cathodes. The microstructural geometry is reconstructed from focused-ion-beam–scanning-electron-microscopy (FIB-SEM) experiments. Raw data from FIB-SEM experiments are processed into finite-volume discretizations that are directly suited for three-dimensional computational simulation. The model represents transport and electrochemistry within the solid phase of the electrode structure. The results predict the temporally and spatially varying Li concentrations and electrostatic potentials within the solid-phase electrode material (e.g., LiCoO2) as functions of discharge rate. The models predict global discharge characteristics that are consistent with experiment. Moreover, the results reveal significant three-dimensional spatial variations within the actual electrode structure that cannot be predicted with models based on idealized microstructures such as spherical electrode particles.

► Segments of Li-ion battery cathodes are reconstructed from FIB-SEM experiments.
► The three-dimensional reconstructed cathode is discretized using a cut-cell approach.
► A Three-dimensional model of cathode performance is developed.
► Three-dimensional simulations reveal significant spatial variations in concentrations and voltage.