Lithium ion intercalation into graphite in aqueous media

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K19087
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 36:Inorganic materials chemistry, energy-related chemistry, and related fields
• Research Institution: Osaka University
• Principal Investigator: Yamada Yuki 大阪大学, 産業科学研究所, 教授 (30598488)
• Project Period (FY): 2022-06-30 – 2024-03-31
• Keywords: リチウムイオン電池 / 安全性 / 水系電解液 / 水和融体 / 黒鉛 / 界面

Outline of Final Research Achievements

This work aimed to replace the electrolyte used in lithium-ion batteries from a flammable organic solvent to a non-flammable and safe water. To achieve this goal, ,it is necessary to suppress the reductive decomposition of water (hydrogen evolution reaction) on the surface of graphite negative electrodes. We demonstrated that the surface coating of graphite negative electrodes with a hydrophobic organic solution and polymer film, in combination with a hydrate melt electrolyte with a peculiar coordination state of water molecules, is effective in suppressing the reductive decomposition of water.

Free Research Field

電気化学

Academic Significance and Societal Importance of the Research Achievements

水系電解液は、二次電池だけでなく、キャパシタや各種電解反応でも広く用いられており、本研究で見いだされた水分解抑制手法は、さまざまな電気化学反応の可能性を広げる重要な意義がある。また、高性能の水系リチウムイオン電池が実現すれば、電池に起因する発火事故のリスクを大幅に下げることができ、リチウムイオン電池の更なる用途拡大につながる。