Physicochemically-informed continuum level model of a solid electrolyte interphase growth in Li-ion batteries

Despite extensive research, understanding the SEI’s formation mechanism, structure, and its impact on battery performance remains challenging due to its complexity. To enable model-based design studies and to enhance understanding and prediction of the macroscopically observable consequences of SEI layer on battery performance and safety, continuum models featuring high level of prediction capability are needed. This objective of this paper is to resolve this challenge through an innovative physicochemically-informed continuum level model derived using a scale-bridging methodology, which, for the first time, enables highly consistent transfer of detailed KMC level based governing equations and reactions rates to the physicochemically-informed continuum level model. This was made possible by the innovative methodology relying on identification of rate-limiting reactions, deriving dynamic equations, and implementing dimensionality reduction. The resulting continuum model accurately replicates KMC results and experimental results while significantly reducing computational complexity. Furthermore, it, for the first time, enables distinguishing between ‘bad’, ‘good’, and ‘inorganic’ SEI growth scenarios on the continuum scale, offering valuable insights into electrode/electrolyte interface design. Due to its computational efficiency and scalability the proposed model can be integrated into higher-scale battery models, making possible advanced virtual performance, degradation and safety assessments with higher level of prediction capability. • A novel continuum model for SEI growth in Li-ion batteries, derived from a KMC model. • Innovative upscaling method preserves physicochemical consistency with a KMC model. • The model accurately predicts SEI properties such as thickness and porosity. • Demonstrates good agreement with both KMC simulations and experimental data. • Computationally efficient, allowing integration into continuum level battery models.