Liquid phase synthesis of sulfur-carbon replica-solid electrolyte composite and its electrochemical performance in all-solid-state lithium-sulfur battery system

2019 Fiscal Year Final Research Report

• Project/Area Number: 18K14304
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 36010:Inorganic compounds and inorganic materials chemistry-related
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Suzuki Kota 東京工業大学, 物質理工学院, 助教 (40708492)
• Project Period (FY): 2018-04-01 – 2020-03-31
• Keywords: リチウム硫黄電池 / 全固体電池 / 固体電解質 / 液相合成

Outline of Final Research Achievements

Liquid-phase synthesis and mixing of Li10GeP2S12 electrolyte were conducted for the fabrication of all-solid-state lithium-sulfur battery cathodes. Also, an increase in the energy density of the cathode was examined. Optimization of the mixing process using the Li10GeP2S12 suspensions realized the high cycle stability of the battery, indicating the superiority of the liquid phase method. Various factors such as solid mass fraction and agitation time affect the precipitation of Li10GeP2S12 from the homogeneous solution, while the obtained materials after sintering showed comparable ionic conductivity to the as-prepared sample. The sulfur-carbon replica composites prepared by the dissolution-diffusion method have a sulfur content of 80 wt%, and the cycle stability can be improved by controlling the particle size of various materials.

Free Research Field

無機固体化学

Academic Significance and Societal Importance of the Research Achievements

全固体リチウム電池には硫化物系の固体電解質が広く用いられており、酸化物材料と比べて反応性が高く、安定性が低いことが課題となっている。理論計算に基づく情報はあるが、実用上重要な速度論を含んだ知見は少ない。本研究では液相合成を介して、溶媒への溶解度、溶解中の分解などについて多くの実データを得ることが出来た。また、液相を介した無機固体材料の取り扱いや複合化は、今後の実用化において重要な技術の一つとなっているため、硫黄電池に限らず、様々な固体デバイスへ応用可能であると考えられる。