Unplanned discovery could lead to future pivotal discoveries in batteries, fuel cells, devices for converting heat to electricity and more.
Scientists normally conduct their research by carefully selecting a research problem, devising an appropriate plan to solve it and executing that plan. But unplanned discoveries can happen along the way.
Mercouri Kanatzidis, professor at with a joint appointment in the U.S. Department of Energy’s (DOE) Argonne National Laboratory, was searching for a new superconductor with unconventional behavior when he made an unexpected discovery. It was a material that is only four atoms thick and allows for studying the motion of charged particles in only two dimensions. Such studies could spur the invention of new materials for a variety of energy conversion devices.
“Our analysis results revealed that, before this transition, the silver ions were fixed in the confined space within the two dimensions of our material, but after this transition, they wiggled around.” — Mercouri Kanatzidis, joint appointment with Argonne and Northwestern University
Kanatzidis’s target material was a combination of silver, potassium and selenium (a-KAg3Se2) in a four-layered structure like a wedding cake. These 2D materials have length and width, but almost no thickness at only four atoms high.
Superconducting materials lose all resistance to the movement of electrons when cooled to very low temperatures. “Much to my disappointment, this material was not a superconductor at all, and we could not make it one,” said Kanatzidis, who is a senior scientist in Argonne’s Materials Science Division (MSD). “But much to my surprise, it turned out to be a fantastic example of a superionic conductor.”
In superionic conductors, the charged ions in a solid material roam about just as freely as in the liquid electrolytes found in batteries. This results in a solid with unusually high ionic conductivity, a measure of the ability to conduct electricity. With this high ionic conductivity comes low thermal conductivity, meaning heat does not pass through easily. Both of these properties make superionic conductors super materials for energy storage and conversion devices.
The team’s first clue that they had discovered a material with special properties was when they heated it up to between 450 and 600 degrees . It transitioned into a more symmetrical layered structure. The team also found this transition to be reversible when they lowered the temperature, then raised it again into the high temperature zone.
“Our analysis results… Brinkwire News Summary.