Smoothed particle hydrodynamics prediction of effective transport coefficients of lithium-ion battery electrodes

We develop a three-dimensional virtual physical property test platform based on the smoothed particle hydrodynamics (SPH) method for the prediction of the effective transport coefficients, including the effective thermal conductivity, effective electronic conductivity, and effective Li+ species diffusivity of LiCoO2 electrodes of various microstructures. The three-dimensional microstructure of the LiCoO2 electrode is reconstructed by a sphere-based simulated annealing method. SPH simulation results corroborate that the transport processes are strongly affected by the electrode microstructure. The calculated effective thermal conductivity by SPH model agrees well with the theoretical predictions by a semi-empirical effective medium model, while the effective medium model generally gives smaller effective electronic conductivity of the electrode than the SPH model. Comparing the SPH-predicted effective Li+ species diffusivity with the commonly-used Bruggeman approximation finds that the latter generally overestimates the effective Li+ species diffusivity of the electrode. Furthermore, we derive the formation factor of electrolyte phase in the reconstructed electrode. It is found that the formation factors calculated from SPH results are in good agreement with former experimental data.