Superconductors about to get a lot more super with hydrogen

28 Jul 2016

In what is a major breakthrough, a team of researchers created a new class of materials using hydrogen, to create a superconductor like no other.

In a future where transport systems like the Hyperloop are the norm, superconductors will be instrumental thanks to the phenomenon that allows a material to be a conduit for electricity with zero electrical resistance.

Superconductivity is characterised by the expulsion of a magnetic field from the interior of the superconductor as it transitions into the superconducting state. This effectively forms an electromagnet that would repel a magnet brought near the surface of the superconductor, causing it to levitate.

This levitation property makes superconductivity one of the most exciting areas in materials science, and within this, the ability to harness hydrogen – specifically, a metallic state of hydrogen – is seen as the ‘holy grail’, as it would be considerably more efficient than any other existing superconductor material

Use in hydrogen fuel cells

With this in mind, researchers from the Carnegie Institute of Science have now managed to produce a new class of materials that blends hydrogen and sodium.

These findings, published in Nature Communications, could be a game-changer both for hydrogen fuel cell storage, and superconductors in general.

The Carnegie team took a 40-year-old theory that a sodium/hydrogen material would be stable under pressure, and began putting a prototype material under high-pressure and high-temperature experiments.

Unusual and unique properties

By squeezing lithium and sodium samples to enormous pressures in a diamond anvil cell while also heating the samples using a laser, structures known as polyhydrides formed in very unusual configurations.

More specifically, three negatively-charged hydrogen atoms lined up to look like one-dimensional hydrogen chains, which is a new phase that is very different from pure hydrogen.

“The only superconductors that have been produced can only exist at impractically cold temperatures,” said lead researcher, Viktor Struzhkin.

“In recent years, there have been predictions of compounds with several atoms of hydrogen coupled with alkali metals that could exist at more practical temperatures. They are theorised to have unique properties useful to superconductivity.”

The next step in making this superconducting material available to a wider market is to see if it can be produced at lower temperatures and pressures, Struzhkin added.

Superconductor in action image via Trevor Prentice/Flickr

Colm Gorey was a senior journalist with Silicon Republic