Model Based Multiscale Analysis of Film Formation in Lithium‐Ion Batteries

Abstract

Evidence for multiscale interaction of processes during surface film growth is provided using a multiscale modeling approach. The model directly couples a continuum pseudo two dimensional (P2D) battery model and a heterogeneous surface film growth model based on the kinetic Monte Carlo (kMC) method. Key parameters have been identified at basic electrochemical experiments, i. e., open circuit potential (OCP), C‐rate tests, and potential during filmformation. Simulations are in very good agreement with these experiments. Simulation results are shown for various formation procedures, i. e., for different applied C‐rates. Interaction between macroscopic transport processes on electrode scale and elementary reaction steps on atomistic scale are observed. Results reveal a distinct impact of the applied procedures on the atomistic structure of surface films. It can be seen that locally heterogeneous films are formed with very slow charging rate due to stochasticity of the growth process, while spatially heterogeneous films are formed with very fast charging rate due to the spatial heterogeneous distribution of concentration and potential. Therefore, the author's emphasize that in order to identify charging protocols for optimal film morphology multiscale interactions should be considered.

The Effects of Gas Saturation of Electrolytes on the Performance and Durability of Lithium‐Ion Batteries

“…The SEI potential curve was again similar for all gases, excluding C 2 H 2 . SEI formation was assumed to start when a first plateau is visible; [51] it initiated at approximately 0.7 V for all gases except for C 2 H 2 , which started 0.2 V earlier at 0.9 V. C 2 H 2 , with its highly reactive triple bond, has the lowest reaction barrier and thus reacts non‐specifically with all possible reaction partners in the cell, leading to a complex and unfavorable SEI composition. Furthermore, the gases lead to deviations during lithium intercalation.…”

Strategies towards enabling lithium metal in batteries: interphases and electrodes

“…12,46 The SEI nucleation and growth morphologies are analyzed by modelling transport and reaction processes considering the different SEI components. [81][82][83][84][85] The SEI constitutes a resistance for lithium ion transport between electrode and electrolyte. 86 Anions are immobilized in the SEI, 78 while a combined experimental/theoretical analysis indicates that lithium ions migrate through the SEI.…”

Practical identifiability of electrochemical P2D models for lithium-ion batteries

“…Due to new applications for models and a significant increase of computational power, a wide variety of models has been developed and different applications have been addressed, e.g., models have been used to quantify solid-electrolyte interface (SEI) formation and aging [14,34,39]. The variety of models is summarized in reviews about modeling of LIBs with focus on systems engineering, multi-scale modeling, and state estimation in electric cars, respectively [12,19,28,33].…”