Simulation of Fabrication and Degradation of All-Solid-State Batteries with Ductile Particles

Abstract

We simulated cold press fabrication and intercalation damage in a sulfide All-Solid-State Battery (ASSB) electrode using the Discrete Element Method. We developed a new cohesive hybrid-particulate model that both can simulate particle consolidation during fabrication and material failure during intercalation expansion. In this way, the effect of the fabrication conditions on the mechanical degradation of the electrode can be simulated. The high pressure in the cold press fabrication cause plastic deformation and build-up of cohesive contacts between the particles, consisting of Si active material (AM) and sulfide solid electrolyte (SE), resulting in densification of the electrode. During charging, when AM expands during lithiation, the AM-SE contact area increases but the effective SE conductivity decreases. When the expansion is small, the contact area and conductivity may recover to their original value. However, large expansion may cause plastic deformation and cracking that cause permanent reduction of both contact area and SE conductivity. This type of mechanical degradation was significantly less for electrodes fabricated at higher pressures. This model can become a valuable tool to improve the durability and performance of future ASSBs.