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 Saving energy by taking a close look inside transistors
10.01.2019 | Friedrich-Alexander-Universität Erlangen-Nürnberg

nachricht Tandem Solar Cells – Record Efficiency for Silicon-based Multi-junction Solar Cell
08.01.2019 | Fraunhofer-Institut für Solare Energiesysteme ISE

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: Ultra ultrasound to transform new tech

World first experiments on sensor that may revolutionise everything from medical devices to unmanned vehicles

The new sensor - capable of detecting vibrations of living cells - may revolutionise everything from medical devices to unmanned vehicles.

Im Focus: Flying Optical Cats for Quantum Communication

Dead and alive at the same time? Researchers at the Max Planck Institute of Quantum Optics have implemented Erwin Schrödinger’s paradoxical gedanken experiment employing an entangled atom-light state.

In 1935 Erwin Schrödinger formulated a thought experiment designed to capture the paradoxical nature of quantum physics. The crucial element of this gedanken...

Im Focus: Nanocellulose for novel implants: Ears from the 3D-printer

Cellulose obtained from wood has amazing material properties. Empa researchers are now equipping the biodegradable material with additional functionalities to produce implants for cartilage diseases using 3D printing.

It all starts with an ear. Empa researcher Michael Hausmann removes the object shaped like a human ear from the 3D printer and explains:

Im Focus: Elucidating the Atomic Mechanism of Superlubricity

The phenomenon of so-called superlubricity is known, but so far the explanation at the atomic level has been missing: for example, how does extremely low friction occur in bearings? Researchers from the Fraunhofer Institutes IWM and IWS jointly deciphered a universal mechanism of superlubricity for certain diamond-like carbon layers in combination with organic lubricants. Based on this knowledge, it is now possible to formulate design rules for supra lubricating layer-lubricant combinations. The results are presented in an article in Nature Communications, volume 10.

One of the most important prerequisites for sustainable and environmentally friendly mobility is minimizing friction. Research and industry have been dedicated...

Im Focus: Mission completed – EU partners successfully test new technologies for space robots in Morocco

Just in time for Christmas, a Mars-analogue mission in Morocco, coordinated by the Robotics Innovation Center of the German Research Center for Artificial Intelligence (DFKI) as part of the SRC project FACILITATORS, has been successfully completed. SRC, the Strategic Research Cluster on Space Robotics Technologies, is a program of the European Union to support research and development in space technologies. From mid-November to mid-December 2018, a team of more than 30 scientists from 11 countries tested technologies for future exploration of Mars and Moon in the desert of the Maghreb state.

Close to the border with Algeria, the Erfoud region in Morocco – known to tourists for its impressive sand dunes – offered ideal conditions for the four-week...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Our digital society in 2040

16.01.2019 | Event News

11th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Aachen, 3-4 April 2019

14.01.2019 | Event News

ICTM Conference 2019: Digitization emerges as an engineering trend for turbomachinery construction

12.12.2018 | Event News

 
Latest News

A new twist on a mesmerizing story

17.01.2019 | Physics and Astronomy

Brilliant glow of paint-on semiconductors comes from ornate quantum physics

17.01.2019 | Materials Sciences

Drones shown to make traffic crash site assessments safer, faster and more accurate

17.01.2019 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>