九州大学 エネルギー基盤技術国際教育研究センター

Energy Storage Division – Shigeto OKADA – – Atsushi INOISHI –

Electricity Storage Technology

Professor

Shigeto OKADA

Specialization

Rechargeable battery technology

Affiliation

Institute for Materials Chemistry and Engineering

Assistant Professor

Atsushi INOISHI

Specialization

Solid-state electrochemistry, Inorganic material chemistry

Affiliation

Research and Education Center for Advanced Energy Materials, Devices, and Systems

Research Topics

  • Development of a new redox couple with multi-electron reaction to improve the energy density
  • Development of an aqueous Na-ion battery to suppress the material cost and environmental impact
  • Development of a solid-state rechargeable battery to improve the safety, cyclability and reliability
  • Investigation of the degradation and thermal runaway mechanism to improve the chemical and thermal stability

Research Outline

The goal of this study is to develop low-cost, high-efficiency large-size rechargeable batteries. We hope to simultaneously provide solutions to two urgent national issues; earthquake reconstruction support through providing solutions to electricity shortages caused by Fukushima nuclear power plant accident and the industry restructuring from electronics to energy industry by Japan’s world-class battery technology. Under the NEDO RISING and MEXT ESICB project, some researches of post Li-ion battery are being conducted, to realize large-scale rechargeable batteries such as aqueous Na-ion battery.

Typical cathode candidates for next generation Li-ion battery

Typical cathode candidates for next generation Li-ion battery

Both low cost and high capacity were realized in FeF<3 iron fluoride cathode (JP 5091517).

Discharge/charge profiles of organic Na2C6O6 cathode against Na/Na+.

Discharge/charge profiles of organic Na2C6O6 cathode against Na/Na+

The largest capacity in organic cathodes for Na-ion battery was found in disodium rhodizonate Na2C6O6 (PCT/JP2013/059109).

Electrochemical window of aqueous Na-ion batteries (left) and the redox voltage of the various cathode/anode candidates (right).

Electrochemical window of aqueous Na-ion batteries (left) and the redox voltage of the various cathode/anode candidates (right).

Rechargeable charge-discharge reaction in aqueous Na-ion battery was first realized by using NASICON-type NaTi2(PO4)3 anode (PCT/JP2012/058123).