Development of Super-ionic Conductor using Fluoride Sulfide

2020 Fiscal Year Final Research Report

• Project/Area Number: 19K22239
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 36:Inorganic materials chemistry, energy-related chemistry, and related fields
• Research Institution: Ritsumeikan University
• Principal Investigator: Orikasa Yuki 立命館大学, 生命科学部, 准教授 (20589733)
• Co-Investigator(Kenkyū-buntansha): 中村 崇司 東北大学, 多元物質科学研究所, 准教授 (20643232)
• Project Period (FY): 2019-06-28 – 2021-03-31
• Keywords: 固体電解質 / フッ化物イオン伝導体 / 二次電池 / 全固体電池

Outline of Final Research Achievements

A solid electrolyte was newly synthesized using a group of fluoride sulfides containing two types of anions (fluoride ions and sulfide ions with a larger polarizability), and their ionic conductivity was analyzed. Screening was performed using the reported crystal structure of fluorinated sulfide, and Yb3F4S2, which is presumed to have a small barrier, was used as the material for the initial study. From the evaluation of conductivity characteristics, it was clarified that the activation energy with low ionic conduction was realized, while electron conduction was exhibited. In order to control the electronic conductivity of Yb3F4S2, cation substitution was performed and La2SrF4S2 was synthesized. From the evaluation of conductivity and electrochemical stability, a novel solid electrolyte using fluoride ions as a carrier was found.

Free Research Field

固体電気化学

Academic Significance and Societal Importance of the Research Achievements

フッ化硫化物群がフッ化物イオン伝導体として、大きな潜在性を有している点と、フッ化物イオン伝導の高速化の指針を提示した。複合アニオン化合物の幅広い潜在性を示すだけでなく、新奇なフッ化物イオン伝導体設計への道筋を示す端緒となる重要な知見を見いだした。