Investigating the production of all-solid-state battery composite cathodes by numerical simulation of the stressing conditions in a high-intensity mixer

All-solid-state batteries (ASSB) are considered as attractive further development of conventional lithium-ion batteries, since they are expected to deliver higher energy and power densities. So far, ASSB with inorganic solid electrolytes have not been applied in large-scale due to difficulties in processing, insufficient overall ionic conductivities, and high interfacial resistances between active material and solid electrolyte. In this publication, the influence of stressing conditions on the scalable production of ASSB composite cathodes via a high-intensity mixer is investigated. The high-intensity mixer is supposed to circumvent the challenge of high interfacial resistances within an ASSB cathode consisting of submicron-sized active material LiFePO4, carbon black and solid electrolyte Li3InCl6. The mixing process is simulated employing the discrete-element-method, from which the stressing conditions acting on the particles are extracted and linked with microstructural observations and electrochemical data. These investigations show that the capacity of the ASSB increases with increasing specific energy input, which is, however, limited by a certain stress intensity determined by the rotational speed of the mixer. This examination of the influence of stressing conditions on the production and electrochemical performance of ASSB cathodes lays the foundation for further simulations and experimental investigations in the field of up-scaled ASSB cathode production.