Hokkaido University Research Profiles


All-solid-state Lithium Secondary Battery with an Inorganic Solid Electrolyte

Preparation of sulfide solid electrolyte from the liquid phase

We have successfully deposited sulfide solid electrolyte through a simple process of dissolving sulfide glass, which exhibits high lithium ion conductivity in an organic solvent, and drying the glass. We have also found that this method is applicable to coating of electrode-active materials.

Content of research

In all-solid-state lithium secondary batteries that use a lithium-ion conductive solid electrolyte, the construction of a good electrode-electrolyte interface is very important to realize high energy-density batteries. We have conducted this research to construct a good electrode-electrolyte interface by preparing sulfide solid electrolytes from the liquid phase. We prepared a homogeneous solution of Li2S-P2S5-based solid electrolytes by dissolving them in N-methylformamide (NMF), and successfully redepositing Li2S-P2S5-based solid electrolytes by removing NMF from the solution. This solution was mixed with LiCoO2, a cathode material, and solid electrolyte was coated on LiCoO2 by removing NMF. Using this solution, we produced an electrode composite. Then, using the obtained electrode composite and sulfide inorganic solid electrolyte, we successfully produced all-solid-state lithium batteries and confirmed the stable operation of the batteries.

Potential for social implementation

  • ・Storage batteries for automobiles
  • ・Storage batteries for electricity storage
  • ・Storage batteries for home use

Appealing points to industry and local governments

All-solid-state lithium secondary batteries, which use inorganic solid electrolytes instead of organic electrolytes, are expected to be developed as a next-generation storage battery with excellent safety and reliability. We have expectations of the active efforts by companies, especially material-related businesses, concerning the practical application of all-solid-state batteries.