A discovery by researchers at the Massachusetts Institute of Technology (MIT) has the potential to make battery powered automobiles far more attractive. The team, led by Gerbrand Ceder, the university's Richard P. Simmons Professor of Materials Science and Engineering, found a way to reduce recharge times for Lithium-ion (Li-ion) batteries by a factor of about 100, allowing batteries large enough to power electric vehicles to be topped off in about five to 10 minutes, depending on the specific capacity of a given electrical grid. The work, supported by the National Science Foundation through the Materials Research Science and Engineering Centers program and the Batteries for Advanced Transportation Program of the U.S. Department of Energy, was presented in the March 12 issue of Nature Magazine.
Several years ago, Cedar's group discovered that the theoretical speed of lithium ions through lithium iron phosphate was far faster than the actual rate. They found bottleneck was caused by the fact that the ions could only enter this base material through a series of "tunnels" located at various positions on its surface. Ceder and graduate student Byoungwoo Kang, were able to circumvent that limitation by creating a unique surface coating structure that serves as a kind of highway that permits the ions to travel unencumbered until they encountered one of these dedicated entry ports. At that point, the ions immediately pass through and begin the formal charging process.
Cedar claims that the new material is robust enough to withstand repeated recharging cycles and opens up the possibility of creating even smaller and lighter Li-ion batteries in the future. He also believes the process may lend itself to use with other kind of battery mediums. The technology has been licensed to Belgium-based Umicore, and U.S. battery company A123Systems also has an option on its use. New strains of super-quick recharging Li-ion cells could start reaching the market within the next few years.
Photo Courtesy MIT/Donna Coveney