Hybrid bilayer electrolytes are scarcely investigated but bear the potential to enable ASSBs. Beyond good ion conductivity (~ 0.1 mS cm -1 ), the anolyte needs to balance chemical stability, contact stability and lithium dendrite suppression on the LM side and compatibility with the catholyte. This complex interplay of chemical, mechanical and microstructural properties of the anolyte motivates the exploration and optimization of different phases that are thermodynamically stable against LM such as the lithium nitride halides. However, the future practicality of LNCl will depend on whether its practical conductivity can be increased.