KIST Develops Improved Lithium All-solid-state Battery

A KIST research team led by Dr. Ryu Seung-ho has developed a highly ion-conductive solid electrolyte by sulfide-based solid electrolyte optimization.

The Korea Institute of Science and Technology (KIST) announced on Jan. 19 that its research team led by Dr. Ryu Seung-ho has developed a highly ion-conductive solid electrolyte by sulfide-based solid electrolyte optimization.

These days, the use of lithium-ion batteries in electric vehicles is increasing rapidly. This type of batteries use a liquid electrolyte, which is combustible, and entail the risk of fire and explosion. Under the circumstances, lithium all-solid-state batteries using a solid electrolyte are attracting increasing attention. Although these are free from the risk, a solid electrolyte is inferior in performance due to its lower lithium-ion conductivity.

The research team raised the conductivity of a sulfide-based solid electrolyte by adding antimony, germanium and extra lithium to argyrodite. According to the team, the new solid electrolyte’s ion conductivity is close to that of a liquid electrolyte and higher than the maximum ion conductivity of argyrodite sulfide-based solid electrolytes.

“Existing sulfide-based solid electrolytes react with moisture when exposed to the atmosphere, which results in toxic hydrogen sulfide gas,” it said, adding, “Our development is capable of reducing the gas generation by at least 70 percent.” Details of the research are available in the latest edition of the ACS Energy Letters journal.