Advanced Multiscale Modeling of Potassium‐Ion Batteries for Interplay of Electrochemical and Mechanical Behavior Across Scales

Potassium‐ion batteries present a promising alternative to address the global lithium shortage. However, their electrochemical performance is significantly hampered by the severe volume expansion of graphite electrodes upon K‐ion intercalation. In this work, a comprehensive multiscale modeling approach is introduced to analyze both the electrochemical and mechanical behavior of potassium‐ion batteries, integrating diffusion coefficient and mechanical properties derived from density functional theory calculations with the 3D particle network model. The research demonstrates that K‐ion concentration influences material properties, such as diffusion coefficients, Young's modulus, and shear modulus, significantly affecting the electrochemical performance and mechanical stability of potassium‐graphite intercalation compounds. Notably, the study reveals that KC 24 exhibits superior mechanical properties compared to KC 16 despite its lower K‐ion concentration due to enhanced electrostatic interactions. Additionally, the concentration dependence of material properties is crucial for accurate electrochemical and mechanical modeling, as constant values lead to substantial discrepancies. The findings highlight the importance of considering K‐ion concentration and staging transitions for precise prediction and optimization of potassium‐ion batteries. This work lays a foundation for future research into mitigating mechanical degradation and improving potassium‐ion battery performance through advanced modeling techniques.