Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Copper ions flow like liquid through crystalline structures

09.10.2018

Atomic insights into superionic crystals could lead to safer, more efficient rechargeable batteries

Materials scientists have sussed out the physical phenomenon underlying the promising electrical properties of a class of materials called superionic crystals. A better understanding of such materials could lead to safer and more efficient rechargeable batteries than the current standard-bearer of lithium ion.


An artistic rendition of the intriguing superionic crystalline structure of CuCrSe2, which has copper ions that move like liquid between solid layers of chromium and selenium, giving rise to useful electrical properties.

Credit: Oak Ridge National Laboratory/Jill Hemman

Becoming a popular topic of study only within the past five years, superionic crystals are a cross between a liquid and a solid. While some of their molecular components retain a rigid crystalline structure, others become liquid-like above a certain temperature, and are able to flow through the solid scaffold.

In a new study, scientists from Duke University, Oak Ridge National Laboratory (ORNL) and Argonne National Laboratory (ANL) probed one such superionic crystal containing copper, chromium and selenium (CuCrSe2) with neutrons and X-rays to determine how the material's copper ions achieve their liquid-like properties. The results appear online on Oct. 8 in the journal Nature Physics.

"When CuCrSe2 is heated above 190 degrees Fahrenheit, its copper ions fly around inside the layers of chromium and selenium about as fast as liquid water molecules move," said Olivier Delaire, associate professor of mechanical engineering and materials science at Duke and senior author on the study. "And yet, it's still a solid that you could hold in your hand. We wanted to understand the molecular physics behind this phenomenon."

To probe the copper ions' behavior, Delaire and his colleagues turned to two world-class facilities: the Spallation Neutron Source at Oak Ridge and the Advanced Photon Source at Argonne. Each machine provided a unique piece of the puzzle.

By pinging a large sample of powdered CuCrSe2 made at Oak Ridge with powerful neutrons, the researchers got a wide-scale view of the material's atomic structure and dynamics, revealing both the vibrations of the stiff scaffold of chromium and selenium atoms as well as the random jumps of copper ions within.

For a narrower but more detailed look at vibration modes, the researchers bombarded a tiny single grain of CuCrSe2 crystal with high-resolution X-rays. This allowed them to examine how the rays scattered off of its atoms and how scaffold vibrations enabled shear waves to propagate, a hallmark of solid behavior.

With both sets of information in hand, Delaire's group ran quantum simulations of the material's atomic behavior at the National Energy Research Scientific Computing Center to explain their findings. Below the phase transition temperature of 190 degrees Fahrenheit, the copper atoms vibrate around isolated sites, trapped in pockets of the material's scaffold structure. But above that temperature, they are able to hop randomly between multiple available sites. This allows the copper ions to flow throughout the otherwise solid crystal.

While more work is needed to understand how the copper atoms interact with one another once both sites become occupied, the findings offer clues as to how to use similar materials in future electronic applications.

"Most commercial lithium ion batteries use a liquid electrolyte to transfer ions between the positive and negative terminals of the battery," Delaire said. "While efficient, this liquid can be dangerously flammable, as many laptop and smartphone owners have unfortunately discovered."

"There are variants of superionic crystals that contain ions like lithium or sodium that behave like the copper in CuCrSe2," Delaire said. "If we can understand how superionic crystals work through this study and future research, we could perhaps find a better, solid solution for transporting ions in rechargeable batteries."

###

This research was supported by the Department of Energy (DE-SC0016166, DE-SC0001299, DE-AC02-06CH11357, DE-AC02-05CH11231, DEAC05-00OR22725).

CITATION: "Selective Breakdown of Phonon Quasiparticles across Superionic Transition in CuCrSe2." J. L. Niedziela, Dipanshu Bansal, Andrew F. May, Jingxuan Ding, Tyson Lanigan-Atkins, Georg Ehlers, Douglas L. Abernathy, Ayman Said, & Olivier Delaire. Nature Physics, 2018. DOI: 10.1038/s41567-018-0298-2

Media Contact

Ken Kingery
KEN.KINGERY@DUKE.EDU
919-660-8414

 @DukeU

http://www.duke.edu 

Ken Kingery | EurekAlert!
Further information:
http://dx.doi.org/10.1038/s41567-018-0298-2

More articles from Materials Sciences:

nachricht New approach improving stability and optical properties of perovskite films
14.02.2019 | City University of Hong Kong

nachricht Calculating correlated materials from first principles
14.02.2019 | Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Regensburg physicists watch electron transfer in a single molecule

For the first time, an international team of scientists based in Regensburg, Germany, has recorded the orbitals of single molecules in different charge states in a novel type of microscopy. The research findings are published under the title “Mapping orbital changes upon electron transfer with tunneling microscopy on insulators” in the prestigious journal “Nature”.

The building blocks of matter surrounding us are atoms and molecules. The properties of that matter, however, are often not set by these building blocks...

Im Focus: University of Konstanz gains new insights into the recent development of the human immune system

Scientists at the University of Konstanz identify fierce competition between the human immune system and bacterial pathogens

Cell biologists from the University of Konstanz shed light on a recent evolutionary process in the human immune system and publish their findings in the...

Im Focus: Transformation through Light

Laser physicists have taken snapshots of carbon molecules C₆₀ showing how they transform in intense infrared light

When carbon molecules C₆₀ are exposed to an intense infrared light, they change their ball-like structure to a more elongated version. This has now been...

Im Focus: Famous “sandpile model” shown to move like a traveling sand dune

Researchers at IST Austria find new property of important physical model. Results published in PNAS

The so-called Abelian sandpile model has been studied by scientists for more than 30 years to better understand a physical phenomenon called self-organized...

Im Focus: Cryo-force spectroscopy reveals the mechanical properties of DNA components

Physicists from the University of Basel have developed a new method to examine the elasticity and binding properties of DNA molecules on a surface at extremely low temperatures. With a combination of cryo-force spectroscopy and computer simulations, they were able to show that DNA molecules behave like a chain of small coil springs. The researchers reported their findings in Nature Communications.

DNA is not only a popular research topic because it contains the blueprint for life – it can also be used to produce tiny components for technical applications.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Global Legal Hackathon at HAW Hamburg

11.02.2019 | Event News

The world of quantum chemistry meets in Heidelberg

30.01.2019 | Event News

Our digital society in 2040

16.01.2019 | Event News

 
Latest News

Gravitational waves will settle cosmic conundrum

15.02.2019 | Physics and Astronomy

Spintronics by 'straintronics'

15.02.2019 | Physics and Astronomy

Platinum nanoparticles for selective treatment of liver cancer cells

15.02.2019 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>