Control of Li-ion Desolvation at the Interface between Cathode and Liquid Electrolyte using Metal Organic Frameworks

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K14727
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 36020:Energy-related chemistry
• Research Institution: Yonago National College of Technology
• Principal Investigator: Shimizu Takeshi 米子工業高等専門学校, 総合工学科, 特命助教 (50845386)
• Project Period (FY): 2021-04-01 – 2023-03-31
• Keywords: 電極|電解液界面 / 脱溶媒和 / 金属有機構造体

Outline of Final Research Achievements

In this study, for the purpose of realizing high-speed charging/discharging based on promotion of desolvation of lithium ions at the electrode/electrolyte interface, we investigated a metal-organic framework MIL-101(Fe) composed of iron ions Fe3+ and 2-aminoterephthalic acid. A lithium-ion battery with -NH2 as the positive electrode active material was fabricated. Charge/discharge and AC impedance measurements of lithium-ion batteries showed that MIL-101(Fe)-NH2 had a larger capacity and a smaller charge transfer resistance than MIL-101(Fe). This suggests that the desolvation of lithium ions at the electrode/electrolyte interface is promoted by the hydrogen bond between the surface hydrophilic group NH2 and the carbonyl group of the electrolyte molecule as the driving force.

Free Research Field

錯体化学　電気化学

Academic Significance and Societal Importance of the Research Achievements

近年、脱炭素社会の実現に向けて電気自動車の普及が進められているが、蓄電池の充電時間が長いため普及率は1割にも満たない。また、電極|電解液界面におけるリチウムイオンの脱溶媒和が律速段階であり、現在の活物質開発技術では脱溶媒和を促進することが困難である。本研究では、活物質に極性基を導入することで蓄電池の充電時間を短縮できることが示唆され、電気自動車の普及に貢献するとともに、電極|電解液界面におけるリチウムイオンの脱溶媒和を促進する新しい手法を見出した。