硫化物ガラス系電解質を用いた全固体電池の開発と今後の展望

抄録

Recently, sulfide solid electrolytes with high Li+ ion conductivities of 10^-3-10^-2 S cm^-1, which are comparable to those of organic liquid electrolytes, have been developed. Sulfide glass-ceramics in the system Li₂S-P₂S₅ are promising solid electrolytes for all-solid-state lithium cells because of their high conductivity and wide electrochemical window. Sulfide electrolytes have another merit of achieving intimate solid/solid contacts by only cold-press without high-temperature sintering. All-solid-state lithium batteries using sulphide electrolytes are expected as a next-generation battery with high safety and reliability. The possible use of active materials with high capacity such as sulfur positive electrode and lithium negative electrode, which are difficult to use in a liquid electrolyte cell, is another advantage of all-solid-state batteries. Here, characterization of electrochemical performance and reaction mechanism for all-solid-state cells with the combination of sulfide glass-ceramic electrolytes and several kinds of active materials were reported. Several approaches to forming a favourable electrode-electrolyte interface were also demonstrated.