The Department of Energy has a target of developing a storage material that holds 6 percent of it's mass in hydrogen. This project hasn't reached that level yet, but it's definite progress. The researchers have used fairly conventional processes to produce polystyrene with a multitude of pores 2 nanometers in diameter. The hydrogen atoms naturally stick to the styrene and at 40 bar pressure, the styrene held 3.8 percent of its mass in hydrogen. That's barely over 1/10th of the pressure that most gaseous hydrogen tanks are using now. This process is far cheaper than other processes like carbon nano-tubes. The goal is develop a safe, inexpensive method of storing hydrogen and this team definitely seems to be progressing in that direction. Click Read for the New Scientist Tech article.
[Source: NewScientistTech, hat tip to John Stockard]