Study on Li ion conduction by fabricating single crystal thin films of all solid-state battery materials without any grain boundaries

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K06737
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Inorganic materials/Physical properties
• Research Institution: National Institute for Materials Science
• Principal Investigator: Ohnishi Tsuyoshi 国立研究開発法人物質・材料研究機構, エネルギー・環境材料研究拠点, 主幹研究員 (80345230)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 機能性セラミックス

Outline of Final Research Achievements

The final goal is to develop ultimately high-power solid-sate Li-ion batteries. In order to achieve this, I was planning to fabricate monolithic single crystal thin films of a cathode material without any grain boundaries. However, in the course of the crystallographic direction alignment of the cathode material by using vicinal single crystal substrates, which also work as current collectors, with step-flow thin film growth, the crystallinity was dramatically improved. The all solid-state thin film batteries by laminating amorphous solid electrolyte- and metal Li-thin films on the crystallinity improved cathode thin films showed ultimately high-power charge/discharge properties. When the cathode film is thin, less than 1 s is enough to fully charge or discharge the thin film batteries.

Free Research Field

工学

Academic Significance and Societal Importance of the Research Achievements

正極材料の結晶方位を揃えてさらに結晶性を上げるとリチウムイオンは非常に高速に移動できることが示された。逆に、結晶方位が乱れていたり結晶性が悪い場合には高速に移動できないが、現状のリチウムイオン電池の正極材料は少なくとも結晶方位がランダムである。すなわち、もし正極材料の結晶方位を揃えたリチウムイオン電池ができればごく短時間で充電ができ、必要なときには大電流でも放電できる電池ができる可能性があることが示された。