Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Safe and effective energy storage media of the future: lithium-sulphur technology

28.09.2017

The Fraunhofer-Gesellschaft in-house LiScell joint project was successfully concluded in May 2017. Lithium-sulphur technology was studied because it might offer an attractive energy-storage solution for future mobility thanks to its low cost of materials and high energy density.

Efficient storage of electrical energy is the bottleneck for all mobile electronic applications.
The weight and cost per kWh of battery storage capacity decisively limit the areas of application in which a product can be employed.


Lithium-sulphur cell electrodes with silicon-alloy anodes

© Fraunhofer IWS, Picture in printable resolution: www.fep.fraunhofer.de/press

For example, energy storage represents the majority of total costs for electric vehicles while simultaneously being the cause of the limited 150-km operating range of fully electric automobiles employing lithium-ion technology. Accordingly, the requirement for new storage media with higher energy densities yet low costs is correspondingly large.

The solution to this can be novel lithium-sulphur batteries, for which future energy densities of up to 500 Wh/kg are expected. Simultaneously, this technology replaces the expensive cathode material of Li-ion cells by the cost-efective and non-toxic sulphur with its nearly unlimited availability.

Research has been carried out over the last three years on advanced development of lithium-sulphur battery cells using new cathodes, electrolytes, and anodes under the Fraunhofer LiScell joint project.

Besides their involvement with materials development, the four participating Fraunhofer Institutes – the Institute for Material and Beam Technology IWS (Dresden), Institute for Organic Electronics, Electron Beam and Plasma Technology FEP (Dresden), Institute for Transportation and Infrastructure Systems IVI (Dresden), and Institute for Chemical Technology ICT (Pfinztal) – were also working on scalable fabrication processes for anodes and cathodes in the form of roll-to-roll foils and on the construction of battery modules. The goal is to advance the state of lithium-sulphur technology for electromobility.

Lithium-sulphur distinguishes itself with its very low material cost and high energy density. As a result, it might represent an attractive energy storage solution for future mobility applications. At up to 400 Wh/kg, these cells already achieve up to 40% higher energy densities than the best lithium ion cells today.

However, the greatest challenge with Li-S cells is to improve their poor cycling ability: they can only be discharged and re-charged 50 to 100 times. The reason for this is a chemical reaction in which the electrolyte attacks the anode surface, consisting of metallic lithium. The scientists focused on this challenge and developed a cell design based around an anode made of a silicon alloy as a
substitute for metallic lithium.

This new anode and cell design was implemented and demonstrated in Li-S and Li-ion prototype cells at the Fraunhofer IWS. New solutions were also found for the fabrication of sulphur cathodes. Dr. Holger Althues, head of the consortium and Department of Chemical Surfaces and Barrier Engineering at the Fraunhofer IWS, explains: “Powdered active materials were processed without solvents by using a dry-film procedure at the Fraunhofer IWS to produce high-performanceelectrodes.”

The advantages of the Si anode technique were determined in safety tests carried out by the Fraunhofer ICT. Li-S cells have a performance edge over conventional energy storage media thanks to their high tolerance to overcharging and thermal stress.

Acquiring precise knowledge about the batteries charging and health state is essential to achieve reliable battery operation. Conventional methods for characterizing the aging process do not work well with this new cell technology, though. “The key for practical application of the technology was using a  sophisticated combination of data- and model-based methods to determine the state of charge and state of aging”, added Dr. Ulrich Potthoff, responsible for this development at Fraunhofer IVI. Finally, suitable economical and efficient fabrication processes needed to be worked out and tested.

“Silicon layers with a specialized micro-scale structure were able to be deposited on both sides of thin charge-collector film made of copper using a new vacuum coating technology in a roll-to-roll process”, as Dr. Nicolas Schiller, director of the Flat and Flexible Products Division, summed up the results at the Fraunhofer FEP. “The layers proved themselves to be suitable anode material for Li-S cells as well as for Li-ion cells. They possess considerable potential for increasing the volumetric energy density compared to conventional solutions.”

Conclusion: following three years of energetic research work, large strides were made in lithium-sulphur technology for energy storage. Among other things, the ability to re-charge the batteries was considerably improved and manufacturing costs were reduced by the application of cost-effective roll-to-roll fabrication processes. Another step towards employing this energy storage system for electromobility and wearables has been taken.

These and other results on the subject of energy storage will be presented in booths and conference  talks, and at the 6th Fraunhofer Li-S Workshop during the industrial trade fair and workshop week on vacuum coating technology and plasma surface engineering entitled “V2017” (24 – 26 Oct. in Dresden) (www.iws.fraunhofer.de/de/ veranstaltungen/lithium-schwefel-batterien_2017.html).

About the LiScell Project

The following participated in the research work on LiScell (an internal Group Project of the Fraunhofer-Gesellschaft) under the MAVO Program for market-oriented preliminary research:

- Fraunhofer Institute for Material and Beam Technology IWS
Dr. Holger Althues

- Fraunhofer Institute for Chemical Technology ICT
Dr. Markus Hagen

- Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP
Dipl.-Ing. Steffen Straach

- Fraunhofer Institute for Transportation and Infrastructure Systems IVI
Dr. Ulrich Potthoff

Project duration: 1 June 2014 – 31 May 2017
Website: www.liscell.fraunhofer.de
Funding: 3.45 Mio EUR

Press contact:

Mrs. Annett Arnold

Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP
Phone +49 351 2586 333 | presse@fep.fraunhofer.de
Winterbergstraße 28 | 01277 Dresden | Germany | www.fep.fraunhofer.de

Weitere Informationen:

http://s.fhg.de/J2U

Silvena Ilieva | Fraunhofer-Institut für Organische Elektronik, Elektronenstrahl- und Plasmatechnik FEP

More articles from Power and Electrical Engineering:

nachricht Researchers take next step toward fusion energy
16.11.2017 | Texas A&M University

nachricht Desert solar to fuel centuries of air travel
16.11.2017 | SolarPACES

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: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

UCLA engineers use deep learning to reconstruct holograms and improve optical microscopy

22.11.2017 | Medical Engineering

Watching atoms move in hybrid perovskite crystals reveals clues to improving solar cells

22.11.2017 | Materials Sciences

New study points the way to therapy for rare cancer that targets the young

22.11.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>