Reducing diffusion-induced stresses of electrode-collector bilayer in lithium-ion battery by pre-strain

Diffusion-induced stresses can break structure integrity of electrodes, and further degrade storage capacity and cycling stability of lithium-ion batteries. To reduce these built-in stresses due to lithium-ion diffusion, we report a strategy of pre-strain applied to the structure of active electrode film bonded to the current collector. Accordingly, a model is developed for the effect of pre-strain on mechanical stress of the electrode-collector structure. The theoretical results show that pre-strain greatly alleviates diffusion-induced stresses of electrode film and current collector, especially stress drop at the electrode-collector interface. In addition, tensile stresses of two electrode surfaces should be modestly tuned by pre-strain, avoiding brittle fracture.