Analysis of diffusion-induced delamination of an elastic-perfectly plastic film on a deformable substrate under potentiostatic operation

Considering the coupling effect between diffusion and stress on diffusion-induced stress presented in a lithium-ion battery, the finite element method is used to analyze the diffusion-induced interfacial delamination of a thin film from a deformable substrate under a potentiostatic condition. Both the film and the substrate are elastic-perfectly plastic, and solute atoms diffuse into the thin film only from top and side surfaces of the thin film. A linear traction-separation law is used to describe the bonding between the film and the substrate. Numerical results show that both the radial stress and the hoop stress in the material near the top surface of the thin film are at a tensile state during lithiation, which can lead to interface damage/delamination and surface cracking concurrently. A film-substrate structure consisting of a substrate with small elastic modulus and yield stress and a thin film of a small film thickness is desirable to inhibit interface damage and delamination.