Tailored sintering of inorganic solid electrolyte by external electric field

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K05151
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 26050:Material processing and microstructure control-related
• Research Institution: Gifu University
• Principal Investigator: Yoshida Michiyuki 岐阜大学, 工学部, 助教 (70431989)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 無機固体電解質 / 焼結 / 微構造制御 / イオン伝導

Outline of Final Research Achievements

In this study, we developed a flash sintering device that applies an alternating electric field to pellet-shaped samples while heating them in an electric furnace. This device allows us to measure the shrinkage of the samples. Using this device, we successfully achieved flash sintering of an oxide-based solid electrolyte, Li1.5Al0.5Ge1.5(PO4) (LAGP). We revealed that the temperature at which flash sintering occurs decreases as the applied electric field increases, and flash sintering occurs at a very low furnace temperature of 280°C with an applied electric field of 300V/cm. Furthermore, we examined the influence of the combination of applied electric field and current on the sintering process and microstructure formation of LAGP. As a result, we found that when flash sintering is performed at relatively high electric fields, the formation of pores on the scale of several tens of micrometers occurs.

Free Research Field

無機材料

Academic Significance and Societal Importance of the Research Achievements

安全性と高エネルギー密度を兼ね備える次世代エネルギー貯蔵デバイスとして、酸化物系固体電解質を用いた全固体電池が注目されている。酸化物系固体電解質を電池に適用する際には「やきもの」と同じ原理で焼き固める必要があるが、高温・長時間の処理を要する従来の焼成法では優れた伝導特性を得るのが難しく、新たな焼成プロセスに対する期待が高まっている。本研究では、外部電場の印加により極めて短い時間スケールで焼結が完了するフラッシュ焼結を、代表的なリチウムイオン伝導酸化物であるLi1.5Al0.5Ge1.5(PO4)で再現することに成功し、酸化物系固体電解質の焼結プロセスの短時間化に新たな可能性を見出した。