Clean-burning natural gas is an attractive alternative fuel. Unfortunately, methane (the main constituent of natural gas) is not as potent as gasoline; a practical natural-gas car therefore requires a tank that is either prohibitively large or that stores the gas at high pressure (a dangerous option).

Researchers at Oak Ridge National Laboratory have patented a material that may solve this problem.

The material consists of carbon fibers a few micrometers in diameter and a few micrometers long, bonded into a block. Gas infiltrates the porous material and adsorbs to the surface of each fiber. A tank containing this material can hold six times as much methane as a conventional tank holds at the same pressure, says Rod Judkins, fossil energy program manager. Oak Ridge is seeking licensees.