Numerical Reconstruction and Characterization Analysis of Microstructure of Lithium-ion Battery Graphite Anode

The real graphite anode of lithium-ion battery is of evident non-isotropic characteristic due to its cascading graphite flakes. An ellipsoid particle-based simulated annealing method is developed to numerically reconstruct the three-dimensional microstructure of graphite anode. The reconstructed anode is a composite of three clearly distinguished phases: pore (or electrolyte), graphite and solid additive, well representing the non-isotropic characteristic of real graphite anode. Characterization analysis of reconstructed electrodes gives information such as the connectivity, the specific surface area of solid or pore phase, and the pore size distribution. The results show that the size of graphite ellipsoids has important effects on the characteristics of electrode: 1) larger size graphite ellipsoids result in larger mean pore size and smaller specific surface area in the reconstructed electrode; 2) changing the polar radius of graphite ellipsoid particles has more pronounced influence on the characteristics of electrode than has changing its equatorial radius.