Abstract
All-solid-state batteries, touted for their enhanced safety and superior energy density, are emerging as the preferred solution for the future, attracting considerable interest in the electric vehicle sector. Currently, this technology is the subject of extensive research in both academic and industrial circles, encompassing the battery sector, materials suppliers and international consortia. However, it remains to be seen whether this trend represents merely a statement of intent or a genuine technological innovation.
In the context of all-solid-state batteries, most of the technological obstacles to their advancement relate to interface management and stability throughout the assembly and operating phases. For example, variations in the composition of cathode particles during battery use generate mechanical problems in the contacts between the electrode particles, which expand or contract, and the solid electrolyte. On the anode side, lithium metal deposition creates complex stress at the interface with the solid electrolyte. This deposition can occur not only at the electrode-electrolyte interface, but also inside the solid electrolyte, in its pores or along grain boundaries. Confined lithium deposition thus generates areas of high " hydrostatic " stress capable of initiating fractures in the electrolyte. Although most failures in these devices are attributable to mechanical problems, most research is focused on improving ion transport and electrolyte electrochemical stability.
In this lecture, after a review of the descriptors of mechanical properties, we will discuss our understanding of the mechanics of solid-state batteries and the effect of the presence of multiple solid-solid interfaces. We will also examine the " materials " solutions that exist to prevent and relieve stresses in order to improve the performance of these devices.
