Development of Energy Conversion Materials Based on Bistability of Polymers

2021 Fiscal Year Final Research Report

• Project/Area Number: 17H03072
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Polymer chemistry
• Research Institution: Waseda University
• Principal Investigator: Oyaizu Kenichi 早稲田大学, 理工学術院, 教授 (90277822)
• Project Period (FY): 2017-04-01 – 2022-03-31
• Keywords: 電荷授受 / 電荷貯蔵 / 双安定性 / レドックス / 有機活物質

Outline of Final Research Achievements

The present study was performed with the aim of fundamental understanding of the charge transport and storage processes in amorphous polymers with densely substituted charge-transfer sites that exhibit electrochemical reversibility. The research also aimed at deriving a generalized concept of redox bistability of polymers.
Specifically, we have organized chemical structures applicable as charge transfer sites and synthesized polymers with small equivalent weights (i.e. high density in monomer units). We also showed that the charge transport efficiency is enhanced by using molecular-level composite electrodes incorporating π-conjugated systems. Based on these findings, we have developed various examples of redox-bistable polymers such as potential-driven mediators that enable high-density charge storage and fast charging, and established them as a group of functional polymers characterized by redox bistability.

Free Research Field

高分子化学

Academic Significance and Societal Importance of the Research Achievements

本研究は，有機ポリマーによる電荷貯蔵を可能とする基本的な考え方であるレドックス双安定性の概念確立とその有用性の実証を通して，有機物に蓄電を担わせる方法を示した点に学術的意義がある。従来の無機材料における廃棄手順の難しさと資源の限界は明白であり、有機物の波及効果と意義は大きい。特に顕著な特性を示した実例として，一連のn型(すなわち電気的中性分子からポリアニオンを与える)ポリマーが挙げられる。その繰返し単位の分子量Mを低く抑え，電位を指標に起電力Uを高めることによってエネルギー密度(= nFU/Σ(M))を増加させると，ロッキングチェア型電荷補償により高電圧・高容量を担うことが明確になった。