Electrode porosity control boosts lithium-air battery output tenfold

The National Institute for Materials Science (NIMS), in collaboration with Seikei University, has successfully enhanced the power output of lithium-air batteries, which are attracting attention as next-generation batteries. By developing a highly porous electrode made of carbon nanotubes, the team achieved a tenfold increase in output current. The lithium-air battery developed in this study not only has extremely high energy density compared to lithium-ion batteries but also significantly improved power performance. As a result, it is now able to supply the power required for hovering small drones, making significant improvements in flight duration feasible. These results were published online in the Journal of Power Sources on February 9, 2025.

Background

Lithium-air batteries (LABs) are rechargeable batteries that operate through discharge and charge reactions using lithium and oxygen. They are attracting attention as an energy storage technology capable of achieving significantly lighter weight and larger capacity than conventional lithium-ion batteries, with a potential energy density 5 to 10 times higher. However, lithium-air batteries have extremely slow reaction kinetics, resulting in only very weak output current. To make use of the large amount of energy stored in lithium-air batteries, a fundamental improvement in their power output has been required.

Key Findings

The research team developed a highly porous carbon nanotube air electrode that significantly improved oxygen accessibility. When combined with a low-viscosity amide-based electrolyte, the new design enabled a tenfold increase in current density. The resulting battery achieved a specific power density sufficient to support hovering in lightweight drones.

Future Outlook

Based on these results, the team aims to scale up lithium-air battery cells, with the goal of developing ultra-lightweight and high-capacity batteries that can be used as power sources for small drones and microrobots.

Other Information

• This research was conducted by a team comprising Dr. Akihiro Nomura (Senior Researcher, Rechargeable Battery Materials Group, Research Center for Energy and Environmental Materials, NIMS); and Dr. Shota Azuma (Visiting Researcher, now at National Institute of Technology, Tokyo College), Dr. Fumisato Ozawa (Assistant Professor), and Prof. Morihiro Saito — all from Faculty of Science and Technology, Seikei University. It was carried out as part of the JST A-STEP Tryout program (Project No. JPMJTM22AQ), the Grants-in-Aid for Scientific Research (KAKENHI, 24K08154), and the NIMS Joint Research Hub Program.
• These findings were published online in the Journal of Power Sources on February 9, 2025.