Hydrogen Storage: The Future in Glass?
One of the key issues in the hydrogen economy is how to store the gas in vehicles, and researchers at a small university in New York are looking at using ultra-thin glass spheres as a storage device that's cheaper, more reliable and safer than metal tanks, reported MSNBC on July 8.
The miniature glass spheres, known as microspheres, "are a much safer method for transporting hydrogen," says Jim Shelby, project leader and professor of ceramic engineering at Alfred University in Alfred, N.Y. "Each tiny microsphere acts as its own pressure vessel. In an accident, they would not break and release a large quantity of hydrogen, as would the rupture of a big tank of gas," he adds. Instead, the spheres would just spill onto the ground, some possibly breaking into beads that would release minute amounts of hydrogen. Each microsphere is smaller than a grain of table salt, and that's exactly what makes it so strong.
"Glass normally breaks due to the presence of very small flaws in the surface," says Shelby. Glass bottles and windows break because they are larger than the flaws, which are about one micrometer long. But since the wall thickness of the spheres is less than that, Shelby notes, "no such flaws can exist in the microspheres." At 50 micrometers in diameter and with a wall that's less than a micrometer thick, each microsphere contains a minute amount of hydrogen. But trillions can be bunched together to make for a sizeable storage system that weighs much less than a traditional heavy steel tank. Made of sand, the microspheres are very light, inexpensive, easily recycled "and can be repeatedly filled and refilled without degradation," he added.