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.

Contact model for DEM simulation of compaction and sintering of all-solid-state battery electrodes

“… [4] was not possible at low mold pressures with this simple DEM model. This is because in this study, aggregates or agglomerates were not simulated as in some earlier studies [ 1 , 2 , 6 ], which could have increased the porosity significantly at low mold pressures. If the low mold pressure region is omitted, we can see that a value of gives reasonably good agreement with the experimental results.…”

“…We recently developed a new contact model of plastic and viscoelastic deformation [2] for ASSB electrode which is indicated by the blue dashpot in Fig. 1 ( a ).…”

“…To simulate the compaction process, a new model of plastic deformation was developed in a series of papers [1 , 2 , 6] . Although some explanations were given, we still concluded that a more in-depth explanation of the model is necessary to explain various mechanisms, its derivation, its applications, and to provide methods for other researchers to reproduce our results.…”

“…The section Introducing the equilibrium overlap describes our the first version of our model for the ASSB electrode [2] , where we adopted the equilibrium overlap concept to simulate the cold pressing process during fabrication. We developed a new method for calculating equilibrium overlap.…”

From Lithium‐Metal toward Anode‐Free Solid‐State Batteries: Current Developments, Issues, and Challenges

“…Recent studies based on sulfide electrolytes show that the initial densification of the cathode is a main factor. [191][192][193] Furthermore, the available capacity of solid-state batteries can be significantly lower than the nominal capacity due to insufficient electronic and ionic percolation in the composite cathode. As a result, not all active material particles are either electronically or ionically connected and the cathode active material utilization is reduced compared to conventional cells.…”