Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Slicing through materials with a new X-ray imaging technique

12.08.2016

Images reveal battery materials' chemical reactions in 5 dimensions -- 3-D space plus time and energy

Researchers at the U.S. Department of Energy's Brookhaven National Laboratory have created a new imaging technique that allows scientists to probe the internal makeup of a battery during charging and discharging using different x-ray energies while rotating the battery cell. The technique produces a three-dimensional chemical map and lets the scientists track chemical reactions in the battery over time in working conditions. Their work is published in the August 12 issue of Nature Communications.


The chemical phase within the battery evolves as the charging time increases. The cut-away views reveal a change from anisotropic to isotropic phase boundary motion.

Credit: Jun Wang

Getting an accurate image of the activity inside a battery as it charges and discharges is a difficult task. Often even x-ray images don't provide researchers with enough information about the internal chemical changes in a battery material because two-dimensional images can't separate out one layer from the next. Imagine taking an x-ray image of a multi-story office building from above. You'd see desks and chairs on top of one another, several floors of office spaces blending into one picture. But it would be difficult to know the exact layout of any one floor, let alone to track where one person moved throughout the day.

"It's very challenging to carry out in-depth study of in situ energy materials, which requires accurately tracking chemical phase evolution in 3D and correlating it to electrochemical performance," said Jun Wang, a physicist at the National Synchrotron Light Source II, who led the research.

Using a working lithium-ion battery, Wang and her team tracked the phase evolution of the lithium iron phosphate within the electrode as the battery charged. They combined tomography (a kind of x-ray imaging technique that displays the 3D structure of an object) with X-ray Absorption Near Edge Structure (XANES) spectroscopy (which is sensitive to chemical and local electronic changes). The result was a "five dimensional" image of the battery operating: a full three-dimensional image over time and at different x-ray energies.

To make this chemical map in 3D, they scanned the battery cell at a range of energies that included the "x-ray absorption edge" of the element of interest inside the electrode, rotating the sample a full 180 degrees at each x-ray energy, and repeating this procedure at different stages as the battery was charging. With this method, each three-dimensional pixel-called a voxel-produces a spectrum that is like a chemical-specific "fingerprint" that identifies the chemical and its oxidation state in the position represented by that voxel. Fitting together the fingerprints for all voxels generates a chemical map in 3D.

The scientists found that, during charging, the lithium iron phosphate transforms into iron phosphate, but not at the same rate throughout the battery. When the battery is in the early stage of charging, this chemical evolution occurs in only certain directions. But as the battery becomes more highly charged, the evolution proceeds in all directions over the entire material.

"Were these images to have been taken with a standard two-dimensional method, we wouldn't have been able to see these changes," Wang said.

"Our unprecedented ability to directly observe how the phase transformation happens in 3D reveals accurately if there is a new or intermediate phase during the phase transformation process. This method gives us precise insight into what is happening inside the battery electrode and clarifies previous ambiguities about the mechanism of phase transformation," Wang said.

Wang said modeling will help the team explore the way the spread of the phase change occurs and how the strain on the materials affects this process.

This work was completed at the now-closed National Synchrotron Light Source (NSLS), which housed a transmission x-ray microscope (TXM) developed by Wang using DOE funds made available through American Recovery and Reinvestment Act of 2009. This TXM instrument will be relocated to Brookhaven's new light source, NSLS-II, which produces x-rays 10,000 times brighter than its predecessor. Both NSLS and NSLS-II are DOE Office of Science User Facilities.

"At NSLS-II, this work can be done incredibly efficiently," she said. "The stability of the beam lends itself to good tomography, and the flux is so high that we can take images more quickly and catch even faster reactions."

###

This work was supported by the DOE Office of Science.

Brookhaven National Laboratory is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.

Media Contact

Chelsea Whyte
cwhyte@bnl.gov
631-344-8671

 @brookhavenlab

http://www.bnl.gov 

Chelsea Whyte | EurekAlert!

More articles from Materials Sciences:

nachricht Researchers devise microreactor to study formation of methane hydrate
23.08.2017 | NYU Tandon School of Engineering

nachricht Meter-sized single-crystal graphene growth becomes possible
22.08.2017 | Science China Press

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Improved monitoring of coral reefs with the HyperDiver

24.08.2017 | Earth Sciences

How cells hack their own genes

24.08.2017 | Life Sciences

What the world's tiniest 'monster truck' reveals

23.08.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>