The present cathode of lithium-ion battery contains such rare metals as cobalt and nickel. It is urgent need to develop a technology to eliminate the content of rare earthes in view of the unstable supply and exorbitant prices of rare earthes. A research team led by Professor Itaru Honma of Tohoku University developed a rare metal-free cathode of lithium-ion battery, and the new cathode has two times bigger capacity than the existing cathode. Although the trial lithium-ion battery that employed the new cathode is as small as a button at the present stage, it attracts wide attention as the second battery of electric vehicles.
The research team used an organic material that is one-fifth in price of the present material. They created a material that contains silica particles of 6 nanometers each and used it as the solid electrolyte to prevent organic particles from dissolving. They build a lithium-ion battery of a button size using this cathode and examined the performance. They confirmed that the energy density, which means storage capacity, is 200 watts per kg, about two times higher than that of the present lithium-ion battery and that it can maintain the original performance even after more than 100 times of discharge and charge. They plan to explore an organic material that has a higher capacity of storing electrons to increase the battery capacity. The research results were published in the June 13 issue of Scientific Reports, a British science magazine.