Single crystal synthesis and characterization of high-voltage positive electrode oxides

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K05249
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 36020:Energy-related chemistry
• Research Institution: National Institute of Advanced Industrial Science and Technology
• Principal Investigator: Akimoto Junji 国立研究開発法人産業技術総合研究所, エネルギー・環境領域, 首席研究員 (20356348)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 全固体電池 / 正極材料 / スピネル型 / 層状岩塩型 / 単結晶 / 結晶構造解析 / フラックス法

Outline of Final Research Achievements

In this study, we studied on the synthesis and characterization of bulk single crystal samples with the aim of elucidating the charging and discharging mechanism of high-potential positive electrode oxide materials in all-solid-state batteries. Specifically, we synthesized single crystals of spinel-type LiCoMnO4, which is one of the 5V class positive electrode materials, and lithium-rich layered rocksalt-type Li1.2Ni0.2Mn0.6O2, which is expected to be used as a high-capacity and high-potential positive electrode. Using a flux synthesis method using lithium hydroxide, we succeeded for the first time in the world in synthesizing single crystals of LiCoMnO4, although the size is only a few microns. In addition, a layered rocksalt-type Li1.2Ni0.2Mn0.6O2 single crystal with a lithium-rich composition with a size of about 100 microns was synthesized using a grain growth method by high-temperature heating.

Free Research Field

無機固体化学

Academic Significance and Societal Importance of the Research Achievements

本研究で得られた単結晶試料を使用することで、次世代蓄電池として期待されている全固体電池でのエネルギー密度向上に資する５Ｖ級正極材料酸化物の充放電メカニズム解明のための研究展開が可能となる。単結晶を用いたリチウム脱離反応に伴う結晶構造変化、および単結晶表面の形態観察などの全固体電池の基礎研究を推進することが可能となる。さらに、得られた基礎解析の結果を材料設計・電池設計に反映させることで、全固体電池の早期実現と更なる高エネルギー密度化のための指針が構築できる。