A cellular automata framework for porous electrode reconstruction and reaction-diffusion simulation

Abstract

Due to the high charge transfer efficiency compared to that of non-porous materials, porous electrodes with larger surface area and thinner solid pore walls have been widely applied in the lithium-ion battery field. Since the capacity and charge-discharge efficiency of batteries are closely related to the microstructure of porous materials, a conceptually simple and computationally efficient cellular automata (CA) framework is proposed to reconstruct the porous electrode structure and simulate the reaction-diffusion process under the irregular solid-liquid boundary in this work. This framework is consisted of an electrode generating model and a reaction-diffusion model. Electrode structures with specific geometric properties, i.e., porosity, surface area, size distribution, and eccentricity distribution can be constructed by the electrode generating model. The reaction-diffusion model is exemplified by solving the Fick’s diffusion problem and simulating the cyclic voltammetry (CV) process. The discharging process in the lithium-ion battery are simulated through combining the above two CA models, and the simulation results are consistent with the well-known pseudo-two-dimensional (P2D) model. In addition, a set of electrodes with different microstructures are constructed and their reaction efficiencies are evaluated. The results indicate that there is an optimum combination of porosity and particle size for discharge efficiency. This framework is a promising one for studying the effect of electrode microstructure on battery performance due to its fully synchronous computation way, easy handled boundary conditions, and free of convergence concerns.