Design of silicon-based porous electrode in lithium-ion batteries: Insights from multiscale electrode model simulations

With the increasing use of silicon-based materials in commercial lithium-ion batteries, the structural design of electrodes has become crucial, necessitating advanced electrode models. Due to the significant electrochemo-mechanical effects from the large volumetric deformation of silicon-based materials, a multiscale electrochemo-mechanical electrode model is essential. In our previous study (Electrochimica Acta, 475 (2024)), we proposed such a model based on the Pseudo-two-dimensional framework developed by John Newman's group. This work utilizes the electrode model as a design tool, exploring three key parameters at the material, electrode, and cell levels: Young's modulus of the binder, the initial porosity of the electrode, and the case pressure. By comparing the predicted rate performance and the reaction and deformation distributions within the electrode under different designs, we offer three recommendations: (a) use a binder with high elasticity that effectively binds with the electroactive materials; (b) ensure the porosity of the pristine silicon-based electrode exceeds 0.6, nearly double that of graphite electrodes, and consider a porosity-graded design; (c) apply an external pressure of approximately 0.25 MPa to the electrode, which preserves structural integrity without harming rate performance.