In Popular Mechanics' November cover story on the hydrogen economy, writer Jeff Wise walked readers through the various hurdles to making hydrogen power practical. At least one of those hurdles, it seems, has just been lowered a notch.

Scientists have invented a material for solid-state storage that absorbs hydrogen at room temperature and atmospheric pressure and releases it at the flick of a switch. This circumvents the problems of storing liquid hydrogen, which must be chilled to near absolute zero, and solid-state storage using metal hydrides, which only work at extremely high temperatures.

The hitch with the new material, which is composed of the heavy metal Rhodium, is that it has a low weight-to-fuel ratio of 0.1%. The U.S. Department of Energy wants 6% of the weight of hydrogen storage systems to be hydrogen in order to achieve mileage comparable to conventional cars.

The most advantageous system, the University of Bath researchers say, might be to use two different storage tanks in tandem. The new material could provide hydrogen as soon as the driver steps on the accelerator, giving metal hydrides the time they need to heat up and take over. --Jennifer Bogo