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 Physics, photosynthesis and solar cells
01.12.2016 | University of California - Riverside

nachricht New process produces hydrogen at much lower temperature
01.12.2016 | Waseda University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>