Lithium-ion batteries could last longer if their electrodes stored more charge. Korean researchers have now made a new type of anode that holds three times more charge than the conventional graphite anodes used in batteries.
The new anode is made of germanium nanotubes. It charges and discharges five times faster than previously reported silicon anodes, lasts through twice as many charging cycles, and is easier to fabricate. Its 400-cycle life matches that of graphite and is long enough for portable-electronics batteries, says Jaephil Cho, a researcher at South Korea's Ulsan National Institute of Science and Technology, who led the new work. "These anodes meet the practical requirements of lithium-ion cells," Cho says.
Cho collaborated with researchers at LG Chem, the Korean company that makes the lithium-ion batteries used in the Chevy Volt. Their results will soon be published online in the journal Angewandte Chemie. The researchers are also working on silicon nanotube anodes.
These advances are part of a broader push by LG Chem to develop better anode materials for higher-capacity batteries. "The company is looking for a breakthrough technology using both silicon and germanium materials for lithium-ion battery anodes," Cho says.