Modeling fracture of solid electrolyte interphase in lithium-ion batteries during cycling

In lithium-ion batteries, the volume change of anode materials will result in fracture of solid electrolyte interphase (SEI) during continuous lithiation and delithiation. Herein, an analytical model has been developed to determine the fracture mechanism of the SEI and the fatigue in lithium-ion batteries. The evolution of diffusion-induced stresses and concentration have been evaluated. In addition, surface effects are found to effectively reduce the stresses and the crack propagation in SEI during lithiation. With combined energy release rate, the critical thickness of SEI is also established to prevent crack propagation. Finally, the capacity fade of lithium-ion batteries during cycling may be predicted using fatigue model. It is found that the depths of discharge (DODs) are closely related to the capacity fade of lithium-ion batteries. Overall, this work may provide physical understanding for optimized structural design to alleviate the SEI fracture and the fatigue of the lithium-ion batteries.