A report out of the Nikkei in Japan states that Toyota achieved the ability to fabricate single crystals of cobalt-oxide for use in lithium ion cells.
A lithium-ion battery stores energy by moving charged lithium ions through a matrix consisting of a carbon graphite anode and various different molecular cathodes. In Toyota's case cobalt oxide is the cathode, but in present technology exists as a large crystalline molecular structure.
In the breakthrough, by creating single crystals, much less graphite is needed thereby making room for more energy storing lithium.
Over the next 10 years Toyota engineers hope to completely eliminate the carbon altogether therefore effectively creating a battery that can hold 10 times the energy in the same mass.
Thus if a battery using today's technology could hold about 60 miles of EV range in a 400 pound pack, when this technique comes of age, 600 miles of range could be stored in the same size battery.
Source (Automotive News, subscription)