Solid electrolytes (SE) are a promising strategy for enhancing the safety of lithium-ion batteries (LIBs). Additionally, a viable SE could allow the use of a Li-metal anode, which would increase energy density. Recently, the anti-perovskite compound, Li₃OCl (LOC), was suggested as a high conductivity SE, with many follow-on studies investigating Li-ion migration mechanisms and pathways for further increasing conductivity. However, the properties of the interface between LOC and a Li metal electrode are also important for performance. For example, the interaction between a SE and an electrode can change the band edge positions of a SE, narrowing its electrochemical window. Furthermore, wetting of the SE by Li metal is desirable for low interfacial resistance and uniform Li plating.

The present study predicts the interfacial energy, wettability, band edge shifts, and the electrochemical window for interfaces between LOC and a Li-metal anode. The oxygen-terminated interface was determined to be the most stable interface termination. The calculated interfacial work of adhesion suggests that Li will wet LOC with a contact angle of 52.6˚, suggesting the possibility for low interfacial resistance and uniform Li deposition. On the other hand, the strong interfacial adhesion significantly narrows the electrochemical window by shifting both of the LOC band edges by more than 1 eV. Nevertheless, the band edges are predicted to be located above the Li/Li⁺ level and below the presumed level for a 4.5 V cathode, which implies a sufficiently wide electrochemical window. Our results illustrate a holistic and systematic strategy for characterizing electrode/electrolyte interfaces in solid state batteries.