Exploration of Ultra-High Voltage Cathodes for Rechargeable Batteries

2021 Fiscal Year Annual Research Report

• Project/Area Number: 20F20038
• Research Institution: The University of Tokyo
• Principal Investigator: 山田 淳夫 東京大学, 大学院工学系研究科(工学部), 教授 (30359690)
• Co-Investigator(Kenkyū-buntansha): DWIBEDI DEBASMITA 東京大学, 工学(系)研究科(研究院), 外国人特別研究員
• Project Period (FY): 2020-04-24 – 2022-03-31
• Keywords: Battery / Cathode / High-Voltage / Capacity / Polyanion / Insertion host

Outline of Annual Research Achievements

The research in 2021 fy focussed on exploring high voltage electro-active materials with increased operating voltages and capacities. One direction of research dwelled on study of mixed polyanionic system (VO)2SO4PO4 for their lithium insertion performances. We expected the incorporation of oxy, sulphate and phosphate anions to render stable framework for alkali ion (Li/Na) insertion with a superior cycling performance. Indeed, we could achieve decent electrochemical performance. However, the structural solutions of the proposed system revealed it to be mixture of phases and could not account for its electrochemical performance, thus making the research ambiguous at this point. Another direction focussed on phase transformations in Na-Fe-S-O quaternary sulphate systems. Here we studied intimate relationship between various Na-Fe-S-O and their hydrated phase with reaction temperature. Also, we studied extensively a metastable phase Na2Fe2(SO4)2 system for its stability, sensitivity, and decent electrochemical activities. This proposed work is near completion, and I am complying all these results for journal publication.

Research Progress Status

令和3年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

令和3年度が最終年度であるため、記入しない。