Multiscale modelling of Si based Li-ion battery anodes

Silicon-based composite anodes continue to raise interest for their high theoretical specific capacity, but the complexity of their behaviour during battery operation presents an obstacle to both their characterization and their practical application. In this paper we present a comprehensive multiscale model of a Si-based composite anode, based on a detailed characterization and encompassing nano-, micro-, and meso-scale details. The model is used to explore the relationship between the chemo-mechanical changes in the anode components and the electrode stability during battery operation, through the prediction of the morphological evolution of the material during the lithiation process. Through the combined analysis of DFT, FEM, and DEM models we highlight the influence of Si and SiO2 lithiation on electrode swelling and damage, and the predominant influence of particle-level morphology on electrochemical behaviour. [Display omitted] •Multiscale model of a SiOx/C composite anode for lithium-ion batteries.•Direct correlation of nano- and micro-scale morphology with electrode stability.•Ab initio theoretical volumetric expansion value for Li3.75Si validated at +244%.•Morphology-specific SiOx/C particle volumetric expansion in the range 60%–100%.•Low-swelling SiOx/C particles preserve up to 90% binder upon lithiation at 875 mAh/g.