Ionic Conduction Analysis across Single Grain Boundary

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K04708
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26020:Inorganic materials and properties-related
• Research Institution: Nagasaki University
• Principal Investigator: YAMADA Hirotoshi 長崎大学, 工学研究科, 准教授 (10359961)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 粒界 / イオン伝導体 / 単一粒界

Outline of Final Research Achievements

This work was conducted to establish a method to measure ion conductivity across single grain boundaries of lithium ion conductor(s) and to reveal ion conduction mechanism on grain boundaries with the method.
First, a measurement system for impedance across a single grain boundary was prepared, with which electrodes with a diameter of 10-50 um were placed on demand. Meanwhile, sintered solid electrolyte pellets were obtained with large grains of 10-500 μm in a diameter. For these pellets, impedance across single grain boundaries was successfully recorded under microscope observation.
It is anticipated that relationship between grain boundary structure and ion conduction for each grain boundary would be clarified by further improvement of measurement accuracy and accumulation of impedance data.

Free Research Field

固体電気化学

Academic Significance and Societal Importance of the Research Achievements

固体電解質は，二次電池や燃料電池などの電気化学デバイスに応用されている。デバイスに用いられる固体電解質は焼結体であり，イオン伝導性は，粒内と粒界の両方の伝導性に影響を受ける。粒内におけるイオン伝導性に関しては，高イオン伝導性を示す結晶構造の探求や伝導機構の解明がなされてきた。一方，粒界におけるイオン伝導性は，個々の試料や試料の焼結方法に強く依存することから，系統的な研究がなされていなかった。
本研究は，単一の粒界におけるイオン伝導性を初めて測定することに成功した。精度の向上とデータの蓄積により粒界のイオン伝導性の理解を深めることを可能にするとともに，電気化学デバイスの特性向上に資する。