Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Turn That Defect Upside Down

26.05.2015

Twin Boundaries in Lithium-Ion Batteries

Most people see defects as flaws. A few Michigan Technological University researchers, however, see them as opportunities. Twin boundaries — which are small, symmetrical defects in materials — may present an opportunity to improve lithium-ion batteries. The twin boundary defects act as energy highways and could help get better performance out of the batteries.


Reza Shahbazian-Yassar

Spotting twin boundary defects in tin oxides requires the aid of a transmission electron microscope: The yellow streaks, highlighted by green arrows, show where lithium ions travel along twin boundaries.

This finding, published in Nano Letters earlier this year, turns a previously held notion of material defects on its head. Reza Shahbazian–Yassar helped lead the study and holds a joint appointment at Michigan Tech as the Richard & Elizabeth Henes associate professor in nanotechnology and an adjunct associate professor in materials science and engineering. Anmin Nie, a senior postdoctoral researcher in his group, conducted the study.

Nie says that material defects, including twin boundaries, are naturally occurring and majority of the past research has focused on removing them from materials.

“We look at the nanostructure of the battery materials that are out there,” he explains. “We have noticed some defects, such as twin boundaries, that exist in these materials can be good channels that will help us to transport lithium ions.”

That movement of ions is key to making better, stronger batteries.

How Lithium-Ion Batteries Work

Batteries power most of our gadgets. Shahbazian-Yassar says, “The focus over the past few years has been on rechargeable batteries — most specifically the lithium-ion battery.”

That’s because lithium-ion batteries are lightweight, pack a whopping punch of energy density, and their efficiency continues to climb. Like all basic batteries, ones run on lithium ions rely on shuttling ions from one place to another. Technically speaking, that’s between the anode and cathode, and an electric current coaxes ions to shuffle between them. A low battery means there is less exchange happening between the anode and cathode. Twin boundaries could help hustle that exchange along or perhaps extend it, hopefully without losing battery life.

Twin boundaries basically are mirror images, places in a material where one side of atomic arrangements reflects another. They often result while making a material, which shifts the atoms out of place a smidge.

“Without a detailed view of the atomic arrangements, one might think the structure of electrode material is perfect, but then when you pay attention at the atomic level, you’ll notice that these atoms are all symmetric with one plane,” Nie says, explaining that the symmetry causes problems because it creates weak spots.

At the same time, that symmetry is what provides a route for ions to travel along. Shahbazian-Yassar and his team received a grant from the Division of Materials Research at the National Science Foundation last fall to explore this and have now shown that a twin boundary acts as a highway for lithium ion transport.

“Usually the available free space within the crystal is what ions use to move in or out of the electrode,” Shahbazian-Yassar says, explaining that the space is like a crowded city with narrow streets and the ions resemble the moving cars. “If there is an accident, road construction, or simply traffic, cars can not easily pass through the streets — similar phenomenon happens in batteries.

Lithium ions need wide and open roads in order to shuttle in and out of the battery electrodes. Any obstruction to the moving ions will reduce the amount of energy or power extracted from a battery.

The research team examined twin boundaries in tin oxides, but Shahbazian-Yassar says it’s applicable in many battery materials. The next step is finding out how to optimize these defects to balance the mechanical integrity with the amount of twin structures. Finding that balance will be the focus of the researchers’ next steps, and this new finding about twin boundaries lays the groundwork for improving lithium-ion batteries.

Michigan Technological University ( www.mtu.edu ) is a leading public research university developing new technologies and preparing students to create the future for a prosperous and sustainable world. Michigan Tech offers more than 130 undergraduate and graduate degree programs in engineering; forest resources; computing; technology; business; economics; natural, physical and environmental sciences; arts; humanities; and social sciences.

Contact Information
Allison Mills
Science & technology writer
awmills@mtu.edu
Phone: 906-487-2343
Mobile: 406-203-2308

Allison Mills | newswise

More articles from Power and Electrical Engineering:

nachricht Producing electricity during flight
20.09.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

nachricht Solar-to-fuel system recycles CO2 to make ethanol and ethylene
19.09.2017 | DOE/Lawrence Berkeley National Laboratory

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Comet or asteroid? Hubble discovers that a unique object is a binary

21.09.2017 | Physics and Astronomy

Cnidarians remotely control bacteria

21.09.2017 | Life Sciences

Monitoring the heart's mitochondria to predict cardiac arrest?

21.09.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>