Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Tiny probe could produce big improvements in batteries and fuel cells

01.06.2016

A new method helps scientists get an atom's level understanding of electrochemical properties

A team of American and Chinese researchers has developed a new tool that could aid in the quest for better batteries and fuel cells.


This is a nanoscale map of the metal ceria produced with the new probe shows a higher response, represented by a yellow color, near the boundary between grains of metal. The higher response corresponds to a higher concentration of charged species.

Credit: Ehsan Nasr Esfahani/University of Washington

Although battery technology has come a long way since Alessandro Volta first stacked metal discs in a "voltaic pile" to generate electricity, major improvements are still needed to meet the energy challenges of the future, such as powering electric cars and storing renewable energy cheaply and efficiently.

The key to the needed improvements likely lies in the nanoscale, said Jiangyu Li, a professor of Mechanical Engineering at the University of Washington in Seattle. The nanoscale is a realm so tiny that the movement of a few atoms or molecules can shift the landscape. Li and his colleagues have built a new window into this world to help scientists better understand how batteries really work. They describe their nanoscale probe in the Journal of Applied Physics, from AIP Publishing.

... more about:
»Applied Physics »battery »nanoscale

Batteries, and their close kin fuel cells, produce electricity through chemical reactions. The rates at which these reactions occur determine how fast the battery can charge, how much power it can provide, and how quickly it degrades.

Although the material in a battery electrode may look uniform to the human eye, to the atoms themselves, the environment is surprisingly diverse.

Near the surface and at the interfaces between materials, huge shifts in properties can occur -- and the shifts can affect the reaction rates in complex and difficult-to-understand ways.

Research in the last ten to fifteen years has revealed just how much local variations in material properties can affect the performance of batteries and other electrochemical systems, Li said.

The complex nanoscale landscape makes it tricky to fully understand what's going on, but "it may also create new opportunities to engineer materials properties so as to achieve quantum leaps in performance," he said.

To get a better understanding of how chemical reactions progress at the level of atoms and molecules, Li and his colleagues developed a nanoscale probe. The method is similar to atomic force microscopies: A tiny cantilever "feels" the material and builds a map of its properties with a resolution of nanometers or smaller.

In the case of the new electrochemical probe, the cantilever is heated with an electrical current, causing fluctuations in temperature and localized stress in the material beneath the probe. As a result, atoms and ions within the material move around, causing it to expand and contract. This expansion and contraction causes the cantilever to vibrate, which can be measured accurately using a laser beam shining on the top of the cantilever.

If a large concentration of ions or other charged particles exist in the vicinity of the probe tip, changes in their concentration will cause the material to deform further, similar to the way wood swells when it gets wet. The deformation is called Vegard strain.

Both Vegard strain and standard thermal expansion affect the vibration of the material, but in different ways. If the vibrations were like musical notes, the thermally-induced Vegard strain is like a harmonic overtone, ringing one octave higher than the note being played, Li explained.

The device identifies the Vegard strain-induced vibrations and can extrapolate the concentration of ions and electronic defects near the probe tip. The approach has advantages over other types of atomic microscopy that use voltage perturbations to generate a response, since voltage can produce many different kinds of responses, and it is difficult to isolate the part of the response related to shifts in ionic and electronic defect concentration. Thermal responses are easier to identify, although one disadvantage of the new system is that it can only probe rates slower than the heat transfer processes in the vicinity of the tip.

Still, the team believes the new method will offer researchers a valuable tool for studying electrochemical material properties at the nanoscale. They tested it by measuring the concentration of charged species in Sm-doped ceria and LiFePO4, important materials in solid oxide fuel cells and lithium batteries, respectively.

"The concentration of ionic and electronic species are often tied to important rate properties of electrochemical materials -- such as surface reactions, interfacial charge transfer, and bulk and surface diffusion -- that govern the device performance," Li said. "By measuring these properties locally on the nanoscale, we can build a much better understanding of how electrochemical systems really work, and thus how to develop new materials with much higher performance."

###

The article, "Scanning Thermo-ionic Microscopy for Probing Local Electrochemistry at the Nanoscale," is authored by Ahmad Eshghinejad, Ehsan Nasr Esfahani, Peiqi Wang, Shuhong Xie, Timothy C. Geary, Stuart Adler and Jiangyu Li. It appears in the Journal of Applied Physics on May 31, 2016 (DOI: 10.1063/1.4949473) and can be accessed at http://scitation.aip.org/content/aip/journal/jap/119/20/10.1063/1.4949473.

The authors of this paper are affiliated with the University of Washington, Xiangtan University and the Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences.

ABOUT THE JOURNAL

Journal of Applied Physics is an influential international journal publishing significant new experimental and theoretical results of applied physics research. See http://jap.aip.org.

Media Contact

AIP Media Line
media@aip.org
301-209-3090

 @jasonbardi

http://www.aip.org 

AIP Media Line | EurekAlert!

Further reports about: Applied Physics battery nanoscale

More articles from Materials Sciences:

nachricht Researchers printed graphene-like materials with inkjet
18.08.2017 | Aalto University

nachricht Superconductivity research reveals potential new state of matter
17.08.2017 | DOE/Los Alamos National Laboratory

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

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>