Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Promising material for lithium-ion batteries

07.06.2013
New framework from boron and silicon could smooth the way to higher capacities

Laptops could work longer and electric cars could drive farther if it were possible to further increase the capacity of their lithium-ion batteries. The electrode material has a decisive influence on a battery’s capacity.


Lithium borosilicid framework -
Image: T. Fässler, M. Zeilinger/TUM

So far, the negative electrode typically consists of graphite, whose layers can store lithium atoms. Scientists at the Technische Universitaet Muenchen (TUM) have now developed a material made of boron and silicon that could smooth the way to systems with higher capacities.

Loading a lithium-ion battery produces lithium atoms that are taken up by the graphite layers of the negative electrode. However, the capacity of graphite is limited to one lithium atom per six carbon atoms. Silicon could take up to ten times more lithium. But unfortunately, it strongly expands during this process – which leads to unsolved problems in battery applications.

Looking for an alternative to pure silicon, scientists at the Technische Universitaet Muenchen have now synthesized a novel framework structure consisting of boron and silicon, which could serve as electrode material. Similar to the carbon atoms in diamond, the boron and silicon atoms in the novel lithium borosilicide (LiBSi2) are interconnected tetrahedrally. But unlike diamond they moreover form channels.

"Open structures with channels offer in principle the possibility to store and release lithium atoms," says Thomas Fässler, professor at the Institute of Inorganic Chemistry, Technische Universitaet Muenchen. "This is an important requirement for the application as anode material for lithium-ion batteries."

High-pressure synthesis
In the high-pressure laboratory of the Department of Chemistry and Biochemistry at Arizona State University, the scientists brought the starting materials lithium boride and silicon to reaction. At a pressure of 100,000 atmospheres and temperatures around 900 degrees Celsius, the desired lithium silicide formed. "Intuition and extended experimental experience is necessary to find out the proper ratio of starting materials as well as the correct parameters," says Thomas Fässler.

Lithium borosilicide is stable to air and moisture and withstands temperatures up to 800 ° Celsius. Next, Thomas Fässler and his graduate student Michael Zeilinger want to examine more closely how many lithium atoms the material can take up and whether it expands during charging. Because of its crystal structure the material is also expected to be very hard, which would make it attractive as a diamond substitute as well.

Since the framework structure of the lithium borosilicide is unique, Fässler and Zeilinger could give a name to their new framework. In honor of their university, they chose the name "tum."

Cooperation partners of the project were the Department of Physics at University of Augsburg and the Department of Materials and Environmental Chemistry at Stockholm University. The work was funded by the TUM Graduate School, the German Chemical Industry Fund, the German Research Foundation, the Swedish Research Council and the National Science Foundation, USA.

Publications:
Michael Zeilinger, Leo van Wüllen, Daryn Benson, Verina F. Kranak, Sumit Konar, Thomas F. Fässler, and Ulrich Häussermann, LiBSi2: A Tetrahedral Semiconductor Framework from Boron and Silicon Atoms Bearing Lithium Atoms in the Channels, Angewandte Chemie International Edition 2013, 52, 5978-5982. DOI:10.1002/anie.201301540.

Michael Zeilinger, Daryn Benson, Ulrich Häussermann, Thomas F. Fässler: Single crystal growth and thermodynamic stability of Li17Si4, Chemistry of Materials 2013, 25, 1960–1967.

Contact:
Prof. Dr. Thomas F. Faessler
Technische Universitaet Muenchen
Inorganic Chemistry with Focus on Novel Materials
Lichtenbergstr. 4, 85747 Garching, Germany
Tel.: +49 89 289 13131

Andreas Battenberg | EurekAlert!
Further information:
http://www.tum.de

More articles from Materials Sciences:

nachricht Argon is not the 'dope' for metallic hydrogen
24.03.2017 | Carnegie Institution for Science

nachricht Researchers make flexible glass for tiny medical devices
24.03.2017 | Brigham Young 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: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>