Topological Defect Engineering on Carbon Electrode for Advanced Batteries

2023 Fiscal Year Final Research Report

• Project/Area Number: 22K14757
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 36020:Energy-related chemistry
• Research Institution: Tohoku University
• Principal Investigator: YU WEI 東北大学, 材料科学高等研究所, 助教 (10900904)
• Project Period (FY): 2022-04-01 – 2024-03-31
• Keywords: Topological Defect / Carbon Materials / Graphene Mesosponge / Lithium-Oxygen Battery

Outline of Final Research Achievements

In this research, we investigated the catalytic effect of topological defects in carbon cathodes on Li-O2 batteries for the first time. In brief, topological-defect-rich and edge-site-free graphene mesosponge (GMS) was synthesized by chemical vapor deposition. Compared with conventional carbons, the GMS cathode shows larger capacity and better cycling stability in Li-O2 batteries. In situ isotopic electrochemical mass spectrometry and theoretical calculations reveal the unique catalysis of topological defects in the formation of easily-decomposable amorphous Li2O2, contributing to a low charge plateau around 3.6 V (vs. Li/Li+). In addition, GMS with abundant topological defects and a large surface area proved to be a good substrate for uniform loading of solid catalyst. Finally, the free-standing GMS-sheet with hierarchical pores shows an ultra-high energy density of 793 Wh kg-1 and excellent cycling stability (> 260 cycles) at a practically high current density of 0.4 mA cm-2.

Free Research Field

エネルギー関連化学

Academic Significance and Societal Importance of the Research Achievements

GMSの合成と活用の成功により，これまで報告されていなかったエッジサイトの影響がない，実際のLi-O2電池のトポロジカル欠陥の触媒能についての知見が得られた．我々はRuを担持したGMSによってトポロジカル欠陥と固体触媒の逐次反応作用を提案した．GMSシートが示す優れた電池性能から，炭素正極の構造を適切に設計することでLi-O2電池の主要な問題のほとんどを解消できると示された．Li-O2電池の問題点であったエネルギー密度とサイクル特性は適切に設計された炭素電極により解消された．この結果から，電気自動車用の高いエネルギー密度をもったLi-O2電池の実用化が促進されると期待される．