Whilst lithium-ion batteries are compact, producing high voltages and have a long life, their energy densities have nearly reached a limit. Acording to the NIMS team, lithium-air batteries have great potential in overcoming this issue, offering highest theoretical energy density.
The team says its research project has developed ‘realistic’ cells with a storage capacity of 30mAh/cm2, compared to the typical 2mAh/cm2 of conventional lithium-ion batteries.
This improvement was achieved through the use of carbon nanotubes (CNTs) as an air electrode material. The team notes the increased capacity can be attributed to CNTs’ large surface area and flexible structure. The researchers are now looking to develop practical high-capacity lithium-air batteries by increasing the energy density in cell layers and removing impurities from the air.