Scientists at Harvard University have succeeded in turning the lightest of all the elements, hydrogen (H2), into a metal.
Thomas D. Cabot, Professor of the Natural Sciences Isaac Silvera and postdoctoral fellow Ranga Dias, have devoted many years to sought the material, called atomic metallic H2.
In their experiments, Silvera and Dias compressed a tiny H2 sample at 495 gigapascal (GPa), or more than 71.7 million pounds per square inch, which is greater than the pressure at the center of the Earth. At such extreme pressures, Silvera explained, solid molecular H2, which consists of molecules on the lattice sites of the solid, breaks down, and the tightly bound molecules dissociate to transforms into atomic H2, which is a metal.
The scientists’ next steps are to understand whether the material is meta-stable. “That means if you take the pressure off, it will stay metallic, similar to the way diamonds form from graphite under intense heat and pressure, but remain diamonds when that pressure and heat are removed,” Explained Silvera.
Understanding whether the material is stable is important because predictions suggest metallic H2 could act as a superconductor at room temperatures.
A room temperature superconductor, Dias said, could transform our transportation system, making magnetic levitation of high-speed trains possible, as well as making electric cars more efficient and improving the performance of many electronic devices.
The material could also provide major improvements in energy production and storage. Because superconductors have zero resistance, superconducting coils could be used to store excess energy, which could then be used whenever it is needed.
NASA has been supporting some of the research as they have discovered that if the metallic H2 is stable at room temperature it would be possible to convert it to molecular H2. Molecular H2 releases an enormous amount of energy which could revolutionise rocketry.
“It takes a tremendous amount of energy to make metallic H2,” Silvera explained. “And if you convert it back to molecular H2, all that energy is released, so that would make it the most powerful rocket propellant known to man.”