Elucidation of potential-dependent hysteresis behavior of electric double layer structure at electrolyte/electrode interface

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K05539
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 34020:Analytical chemistry-related
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Iwahashi Takashi 東京工業大学, 物質理工学院, 助教 (30402423)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 電気化学界面 / ヒステリシス / 電気二重層 / イオン液体 / 二次電池 / 活性化エネルギー / 吸着エネルギー / 活性化障壁

Outline of Final Research Achievements

Electrochemical interfaces play a key role in the electrochemical reaction in the electrochemical systems, such as batteries. Thus, elucidating potential response of electrochemical interface structure is of fundamental issue to understand the origin of electrochemical property of systems. In this study, we demonstrate in situ observation of the electrochemical interfaces by IR-visible sum-frequency generation vibrational spectroscopy (IV-SFG), which has been recognized as a powerful tool to investigate buried interfaces, to clarify the origin of hysteretic ion adsorption/desorption at electrochemical interfaces. The activation energy of ion desorption, which causes the hysteretic potential response of electrochemical interface, was examined by IV-SFG with electric double layer (EDL) model analysis and the activation energy of anion desorption is found to be a root cause of hysteretic ion adsorption/desorption at the electrochemical interfaces.

Free Research Field

物理化学・電気化学・分子分光学・界面化学

Academic Significance and Societal Importance of the Research Achievements

本研究は電解液/電極界面のEDL構造の電位応答計測に加え、これまで困難であったイオン脱離の活性化エネルギーの定量評価を実現した。当該計測技術を二次電池をはじめとする多様な電気化学系に展開することで、電気化学特性と電気化学界面のイオン吸着脱離挙動との相関理解に繋がると考えられる。ゆえに、本研究成果は電気化学界面の基礎的理解の深化に繋がるため、電気化学の研究領域において高い学術的意義を有する。同時に、電気化学界面構造-機能相関の解明は、電気化学デバイス材料開発の指導原理獲得にも貢献し、持続可能な社会に向けたエネルギーデバイスの更なる高性能化にも寄与するため、社会的意義も十分高い。