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 Perovskite-silicon solar cell research collaboration hits 25.2% efficiency
15.06.2018 | Helmholtz-Zentrum Berlin für Materialien und Energie GmbH

nachricht Second heat source optimises heat pump system
12.06.2018 | FIZ Karlsruhe – Leibniz-Institut für Informationsinfrastruktur GmbH

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: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

Im Focus: Photoexcited graphene puzzle solved

A boost for graphene-based light detectors

Light detection and control lies at the heart of many modern device applications, such as smartphone cameras. Using graphene as a light-sensitive material for...

Im Focus: Water is not the same as water

Water molecules exist in two different forms with almost identical physical properties. For the first time, researchers have succeeded in separating the two forms to show that they can exhibit different chemical reactivities. These results were reported by researchers from the University of Basel and their colleagues in Hamburg in the scientific journal Nature Communications.

From a chemical perspective, water is a molecule in which a single oxygen atom is linked to two hydrogen atoms. It is less well known that water exists in two...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Novel method for investigating pore geometry in rocks

18.06.2018 | Earth Sciences

Diamond watch components

18.06.2018 | Process Engineering

New type of photosynthesis discovered

18.06.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>