A collaborative research team from KAIST’s and Kyonggi University’s Department of Materials Science and Engineering developed a high performance lithium-air battery with significantly improved performance and lighter weight. The research team successfully used nanofibers and graphene composite materials to raise the energy performance of lithium batteries to five times that of conventional lithium-ion batteries. The research team was led by Professor Seokwoo Jeon and Professor Il-Doo Kim of KAIST and Professor Yong-Joon Park of Kyonggi University. Their findings were published in the August online issue of Nano Letters.

Lithium-ion batteries are very versatile devices consisting of lithium oxide cathodes and graphite anodes. These batteries are commonly used in portable electronics, such as laptop computers and mobile phones, as rechargeable batteries requires one of the highest energy densities. Yet, these conventional batteries do not show enough energy density to supply energy in electric cars. This hinders the technological development of electric cars, since with the current technology today, electric cars can only travel at most 160 km on a single charge.

To overcome this limitation, the research team improved lithium-air batteries, which carry higher energy density and use oxygen with lithium cathodes and anodes. The challenge of this research was to efficiently let lithium cathodes oxidize when the battery is discharged and deoxidize when charging. However, this reaction process was slow and caused electrical resistance, limiting the efficiency of lithium-air batteries.

To overcome this obstacle, the research team utilized cobalt oxide nanofibers and graphene composite materials. Cobalt oxides show very high catalytic activity and non-oxidized graphene nanoflakes show high surface area and electrical conductivity. By combining the advantages of these materials, the nanocomposite material was able to achieve a superior performance of 1000 mAh/g with 80 charge and discharge cycles.