Nanotubes may give the world better batteries

Rice University scientists are counting on films of carbon nanotubes to make high-powered, fast-charging lithium metal batteries a logical replacement for common lithium-ion batteries.

The Rice lab of chemist James Tour showed thin nanotube films effectively stop dendrites that grow naturally from unprotected lithium metal anodes in batteries. Over time, these tentacle-like dendrites can pierce the battery's electrolyte core and reach the cathode, causing the battery to fail.

That problem has both dampened the use of lithium metal in commercial applications and encouraged researchers worldwide to solve it.

Lithium metal charges much faster and holds about 10 times more energy by volume than the lithium-ion electrodes found in just about every electronic device,includingcellphones and electric cars.

"One of the ways to slow dendrites in lithium-ion batteries is to limit how fast they charge," Tour said. "People don't like that. They want to be able to charge their batteries quickly."

The Rice team's answer, detailed in Advanced Materials, is simple, inexpensive and highly effective at stopping dendrite growth, Tour said.

"What we've done turns out to be really easy," he said. "You just coat a lithium metal foil with a multiwalled carbon nanotube film. The lithium dopes the nanotube film, which turns from black to red, and thefilmin turn diffuses the lithium ions."