Slurry-Processed Glass-Ceramic LI2S-P2S5-LiI Electrolyte for All-Solid-State Li-Ion Batteries

In order to envisage a sulfide electrolyte based all-solid-state Li battery considering the use of Li metal as the anode as well as a scalable cell fabrication process, we evaluated the long-term electrochemical stability of various lithium conducting sulfide superionic conductors interfaced with Li metal anode. Among them, Li2S-P2S5-LiI glass-ceramic electrolyte, which showed a superior compatibility with Li metal as well as a comparable ionic conductivity of 1.35 x 10-3 S/cm, was used as the electrolyte for a slurry-processed all-solid state Li-ion cell. The discharge capacity of the slurry-type cell retained ~88% compared with that of a typical pellet-type one. The porous nature of the slurry-coated layer as well as the hindering effect of a polymeric binder, however, resulted in large overpotentials during charge and discharge. A strategy for further study to overcome these detrimental effects of slurry-processing was discussed.