Combining pressure, electrochemistry to synthesize superhydrides

A new study featured in Proceedings of the National Academy of Sciences offers a potential alternate approach that combines pressure and electrochemistry to stabilize superhydrides at moderate, perhaps even close to ordinary, pressures. Superhydrides are a materials system where temperature superconductivity has been achieved, but only at very high pressures. University of Illinois Chicago's Russell Hemley and researchers from Carnegie Mellon University performed quantum mechanical simulations of superhydrides over a broad range of pressure as well as electrical potentials as found in an electrochemical cell. The results showed that under an electrical potential a number of these materials, including high-temperature superconducting superhydrides, could be stable at much lower pressures. Using a thermodynamic analysis, they constructed pressure-potential phase diagrams that provide an alternate synthesis approach to access phases having high hydrogen content. Their strategy suggests the possibility of making palladium superhydrides, a widely studied material system, and a general concept for synthesizing other hydrides at modest pressures. This approach opens more opportunities for the creation of superhydrides and other materials by combining pressure and electrochemical loading techniques, according to Hemley, UIC professor of physics and chemistry and LAS Distinguished Chair in the Natural Sciences in the College of Liberal Arts and Sciences.