Hany Eitouni has built batteries that are safer, longer-lasting, and able to store more energy in a smaller space than the conventional lithium-ion cells commonly used today. His technology, Eitouni says, could be used in next-generation electric cars and even in the electric grid, which would be a new application for lithium-ion batteries.
While working at the Lawrence Berkeley National Lab, Eitouni figured out how to replace the most dangerous component of lithium-ion batteries: a flammable liquid electrolyte that conducts electricity between the positive and negative electrodes. The more energy packed into a battery, the higher the danger that the liquid electrolyte will catch fire. Previous researchers had tried to sidestep this problem by using gel polymers for the electrolyte, but even these contained flammable solvents.
The solution was a solid material that is made of two linked polymer chains. One polymer is almost as conductive as a traditional liquid electrolyte but a lot less flammable; the other, which is also less flammable, provides mechanical stability so that the electrolyte doesn’t turn into goo. And the battery lasts longer than traditional lithium-ion or previous lithium-polymer cells because the polymer doesn’t react with the charged electrodes.
To commercialize the technology, Eitouni cofounded Seeo in Berkeley, CA, in 2007. He says that the startup’s battery keeps 90 percent of its storage capacity after 2,000 charges (traditional rechargeable batteries lose nearly a third of their capacity after about 500 charges). It also stores 50 percent more energy per kilogram than commercial lithium-ion batteries. Seeo is building a pilot factory that will make large battery packs to smooth out spikes in supply and demand on the electric grid. It’s expected to be completed in 2011. –Kate Greene