High lithium ion conduction of sulfide glass-based solid electrolytes and their application to all-solid-state batteries

Abstract Sulfide glass-based solid electrolytes prepared by melt quenching and mechanical milling were reviewed. The sulfide and oxysulfide glass–ceramic electrolytes in the system Li 2 S–P 2 S 5 –P 2 O 5 with superionic Li 7 P 3 S 11 and Li 3.25 P 0.95 S 4 crystals exhibited high conductivity of over 10 −3 S cm −1 at room temperature and high electrochemical stability. Newly designed all-sulfide batteries 80SnS·20P 2 S 5 /80Li 2 S·20P 2 S 5 /75Li 2 S·25Cu were successfully fabricated; reversible charge–discharge capacities of more than 400 mAh g −1 were observed after the second to 10th cycles. The operation of those all-sulfide lithium secondary batteries is a first step for the realization of the all-solid-state monolithic batteries.