Report: Development of Single Crystals of Lithium Cobalt Oxide Could Lead to 10X Li-ion Battery Capacities in 10 Years
The Nikkei reports that a joint team headed by researchers from Tohoku University and Toyota Motor Corp. has succeeded in fabricating single crystals of lithium cobalt oxide for use as cathode material in automotive lithium-ion batteries.
In a conventional lithium-ion battery, the cathode is made from grains of unaligned polycrystal lithium cobalt oxide sintered together with grains of graphite. The graphite improves the performance of the cathode, but the trade-off is that there is less room inside the cathode for the storage of lithium ions.
To make single crystals of lithium cobalt oxide, the team uses laser deposition to fabricate a layer of amorphous lithium cobalt oxide on a sapphire substrate. It then dopes this with additional lithium and heats the film for one hour at 650 °C. The crystals in the film align in the direction of the substrate and the compound converts to a single crystal.
The researchers will next begin altering the crystal-growth parameters and studying how this changes the electrical properties of the cathode material.
According to the report, they expect it will take around 10 years to develop a cathode material that contains no graphite and that could contribute to an increase of lithium-ion battery capacity of about 10x.