High Capacity, Superior Cyclic Performances in All-Solid-State Lithium-Ion Batteries Based on 78Li 2 S-22P 2 S 5 Glass-Ceramic Electrolytes Prepared via Simple Heat Treatment.

Highly Li-ion conductive 78Li2 S-22P2 S5 glass-ceramic electrolytes were prepared by simple heat treatment of the glass phase obtained via mechanical ball milling. A high ionic conductivity of ∼1.78 × 10-3 S cm-1 is achieved at room temperature and is attributed to the formation of a crystalline phase of high lithium-ion conduction. All-solid-state lithium-ion batteries based on these glass-ceramic electrolytes are assembled by using Li2 S nanoparticles or low-cost commercially available FeS2 as active cathode materials and Li-In alloys as anode. A high discharge capacity of 535 mAh g-1 is achieved after at least 50 cycles for the all-solid-state cells with Li2 S as cathode materials, suggesting a rather high capacity retention of 97.4%. Even for the cells using low-cost FeS2 as cathode materials, same high discharge capacity of 560 mAh g-1 is also achieved after at least 50 cycles. Moreover, the Coulombic efficiency remain at ∼99% for these all-solid-state cells during the charge-discharge cycles.