Exploration of Ultra-High Voltage Cathodes for Rechargeable Batteries

Research Project

Project/Area Number	20F20038
Research Category	Grant-in-Aid for JSPS Fellows
Allocation Type	Single-year Grants
Section	外国
Review Section	Basic Section 36010:Inorganic compounds and inorganic materials chemistry-related
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
Project Status	Completed (Fiscal Year 2021)
Budget Amount *help	¥2,300,000 (Direct Cost: ¥2,300,000) Fiscal Year 2021: ¥1,000,000 (Direct Cost: ¥1,000,000) Fiscal Year 2020: ¥1,300,000 (Direct Cost: ¥1,300,000)
Keywords	Battery / Cathode / High-Voltage / Capacity / Polyanion / Insertion host
Outline of Research at the Start	The aim of the research is to push the current voltage limit of cathodes such that the resulting higher energy density of lithium and/or sodium ion batteries could conveniently meet the current energy demands. In this pursuit, we would perform various optimised synthesis technique to gauge new high voltage electrode systems. Further, we aim to carry a detailed synthesis-structure-property correlation in these cathodes to broaden fundamental understanding on solid-state interfacial chemistry and provide scope for improvising energy/power density and cycling stability of these materials.
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。