The local lithium plating caused by anode crack defect in Li-ion battery

Anode cracks are typical defects in Li-ion batteries, which lead to local lithium plating in the defect region. To avoid lithium plating, it is necessary to study the evolution mechanism, lithium plating condition, parameter sensitivity, and safety boundaries of defects. In this study, an artificial defect was implanted on the anode surface, and the appearance characteristic of dead lithium was observed. Based on finite element simulations, it was confirmed that potential heterogeneity is the core factor for lithium plating and that dead lithium can fill the defect region. The slope of the cathode equilibrium potential had the most significant influence on the lithium plating. The safety boundaries of the defect sizes for different cathode materials were determined. Moreover, based on simulations and experimental verification, the lithium iron phosphate battery working on the potential plateau was found to be capable of tolerating defects, thus providing a novel approach for improving battery safety. •The mechanism of lithium plating caused by the defect is revealed.•The potential heterogeneity in the defective battery is evaluated.•The parameter sensitivity and safety boundary of the defect are calculated.•Strategies to reduce the failure risk of defective batteries are proposed.