Analytical modeling and simulation of porous electrodes:Li-ion distribution and diffusion-induced stress

摘要

A new model of porous electrodes based on the Gibbs free energy is developed, in which lithium-ion (Li-ion)diffusion,diffusion-induced stress(DIS),Butler–Volmer (BV)reaction kinetics,and size polydispersity of electrode particles are considered.The influence of BV reaction kinet-ics and concentration-dependent exchange current density (ECD)on concentration profile and DIS evolution are numer-ically investigated.BV reaction kinetics leads to a decrease in Li-ion concentration and DIS.In addition,concentration-dependent ECD results in a decrease in Li-ion concentration and an increase in DIS.Size polydispersity of electrode par-ticles significantly affects the concentration profile and DIS. Optimal macroscopic state of charge(SOC)should consider the influence of the microscopic SOC values and mass frac-tions of differently sized particles.