Mechanical degradation of the active material due to the charging and discharging of the electrodes is one of the major cause for capacity fade of lithium-ion battery. During the diffusion process, the particles expand, causing stress inside the particles and binders. These stresses lead to the fracture and the separation of the particles from conductive matrix, creating isolated inactive particles. This leads to the capacity fade after the cycling of charging/discharging processes. To study the decohesion fracture, we calculated the traction forces at the interface and concluded that the debonding of the active material tends to begin at the edge of the interface for smaller particles while for larger particles it starts from the center.