Chinese scientists develop first superionic hydride ion conductor at ambient conditions

Chinese scientists have developed the first superionic hydride ion conductor at ambient conditions, according to the Dalian Institute of Chemical Physics under the Chinese Academy of Sciences.

With strong reducibility and high redox potential, the hydride ion (H ) is a reactive hydrogen species and an energy carrier. Materials that conduct pure H　at ambient conditions will be enablers of advanced clean energy storage and electrochemical conversion technologies.

Several H- conductors have already been developed in recent years, but none of the materials could achieve superionic conduction at ambient conditions.

The research team targeted the structure and morphology of trihydrides - hydrides containing three atoms of hydrogen per molecule - of certain rare earth elements (REHx), including Lanthanum (La), according to a research paper published in the journal Nature.

They innovatively adopted the mechanical ball milling method and deformed lanthanum trihydride (LaHx) through impact and shear force, according to the paper.

By creating nanosized grains and defects in the LaHx lattice, the electronic conductivity of LaHx can be suppressed by more than five orders of magnitude. This transforms LaHx into a superionic conductor with record high conductivities at the ambient temperatures -- minus 40 degrees Celsius to 80 degrees Celsius.

The researchers plan to explore the physics underneath the phenomenon and extend the method developed in the study to other hydride materials to broaden the material scope for pure H- conductors.