Study of charging process at positive electrode in rechargeable lithium-air battery

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K15370
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 36010:Inorganic compounds and inorganic materials chemistry-related
• Research Institution: National Institute for Materials Science
• Principal Investigator: MATSUDA Shoichi 国立研究開発法人物質・材料研究機構, エネルギー・環境材料研究拠点, 主任研究員 (30759717)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 次世代蓄電池 / リチウム空気電池 / 硝酸イオン / レドックスメディエーター

Outline of Final Research Achievements

Lithium-air batteries are the most promising candidates for next-generation storage batteries because they enable energy densities two to five times that of existing lithium-ion batteries. However, the high positive electrode reaction overvoltage during charging and the low output density are the biggest problems in putting lithium-air batteries into practical use. The purpose of this study was to clarify the measures to solve the above battery performance problems by focusing on the electrochemical reaction behavior of nitrate ion redx. Specifically, we focused on a mixed electrolyte system of nitrate ion/amide solvent/fluorine solvent, and succeeded in developing an electrolyte that achieves high reaction reversibility for both the oxygen positive electrode and the lithium negative electrode of lithium-air batteries.

Free Research Field

電気化学

Academic Significance and Societal Importance of the Research Achievements

今回開発した硝酸イオン/アミド溶媒/フッ素溶媒の混合電解液系を用いることで、リチウム空気電池の酸素正極・リチウム負極の双方において高い反応可逆性での反応進行が可能となることが明らかとなった。その結果、1mA/cm2, 2mAh/cm2という非常に高い電流密度・面積容量の条件において、リチウム空気電池の充放電反応の作動に成功した。今回提示した電解液開発実施例は、今後の材料開発において、大きな指針となるものであり、リチウム空気電池の早期実用化に大きく寄与するものである。