Ionic Conduction Through Reaction Products at the Electrolyte/electrode Interface in All-Solid-State Li⁺ Batteries

The development of all-solid-state lithium ion batteries has been hindered by the formation of a poorly conductive interphase at the interface between electrode and electrolyte materials. In the manuscript, we shed light on this problem by computationally evaluating potential lithium ion diffusion pathways through metastable arrangements of product phases that can form at 56 interfaces between common electrode and electrolyte materials. The evaluation of lithium-ion conductivities in the product phases is made possible by the use of machine-learned interatomic potentials trained on the fly. We identify likely reasons for the degradation of solid-state battery performance and discuss how these problems could be mitigated. These results provide enhanced understanding of how interface impedance growth limits the performance of all-solid-state lithium-ion batteries.