Developing a multi-scale model for the simulation of adsorption phenomena based on MD and CA: a Li-ion battery case study

Adsorption, an essential surface phenomenon, is involved in many industries, from water purification to energy storage and carbon capture, aiming at negative emission technologies. The need to synthesize new materials for these applications necessitates the development of new, flexible modeling tools to simulate complex conditions. This work introduces a multi-scale model to simulate various adsorption scenarios. It involves simulating the details of interatomic interactions in molecular dynamics simulations and scaling up to a laboratory scale through cellular automaton modeling. To showcase its capabilities, we utilized the simplest form of the model to simulate Li-ion adsorption on the surface of an anatase TiO₂ sheet. The probability of adsorption and desorption for a Li-ion is quantitatively determined through molecular dynamics simulations and subsequently incorporated into the cellular automaton model. This secondary model simulates the kinetic process of adsorption and quantifies the equilibrium degree of surface coverage across varying concentrations, facilitating comparison with the Langmuir isotherm. An inverse relationship between surface coverage and temperature is consistent with theoretical predictions. Given the model’s computational efficiency, which complements molecular dynamics simulations, it offers extensive potential for extension across a broad spectrum of applications where adsorption, intercalation, diffusion, and other critical surface phenomena are fundamental.