Cracks of Silicon Nanoparticles in Anodes: Mechanics–Electrochemical-Coupled Modeling Framework Based on the Phase-Field Method
Binghe Liu, Jun Xu
Abstract
Silicon has become one of the most promising anode materials owing to its high energy density. Nevertheless, the large expansion of it during lithiation leads to crack initiation and propagation, causing capacity degradation of batteries. To understand the underlying mechanism of the cracks in Si particles, herein, we establish a multiphysics model framework based on the phase-field method to study the cracking initiation and evolution in pure silicon nanoparticles. Quantitative relations between cracking evolution characteristics and particle size and lithiation rates are unlocked. A smart charging (lithiation) strategy that may mitigate the crack initiation in silicon nanoparticles is suggested. The results reveal the fundamental relations between the structural properties of silicon nanoparticles and their cracking behaviors and provide a guiding tool for next-generation silicon design and evaluation.