Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Greater Range and Longer Lifetime

26.10.2016

One of the great challenges of electric mobility is effective and reliable storage of electrical energy in vehicles. Not just the discussions about manipulated exhaust values and regular fine dust warnings in cities like Stuttgart have shown that new solutions must be found for the mobility of the future.
Acting on behalf of the University, TLB is in charge of the commercial implementation of these future-orientated technologies on a global level and offers companies opportunities for cooperation and licensing.

In the past, great progress has been made in electric mobility. What's still missing is an efficient, small, stable electrical energy storage unit. Previously either lithium-ion or metal-hydride rechargeable batteries were used in electromobiles. The latter are less effective than the lithium-ion batteries, but much cheaper.


Cross-sectional images created via FIB (focused ion beam)

Photo: IMW, University of Stuttgart


Scanning electron micrograph of a micro-stabilized silicon anode: Right and left the porous layer - in the middle, a stripe of unirradiated material.

Photo: IPV, University of Stuttgart

For mobile applications, a small and lightweight energy storage unit with a high charging capacity is required. Predestined for this are lithium-ion rechargeable batteries with a silicon anode. Most lithium-ion rechargeable batteries in the past have had graphite anodes, while the silicon anode offers a much larger charge capacity, but it has a big disadvantage: when charging and discharging, its volume extends and shrinks by up to 270%. This leads to mechanical strain that destroys the anode after only a few charging cycles.

Scientists at the University of Stuttgart have now developed two new processes for using silicon with a tailored structure in this area. Both groups are working on manufacturing a porous silicon anode and stabilizing it in order to achieve great charge cycle stability.

At the Institute for Photovoltaics (IPV) of the University of Stuttgart, Prof. Dr. Jürgen H. Werner and his team have succeeded in manufacturing porous and thus micro-stabilized silicon anodes. This micro-stabilization can be accomplished in a simple process step with local laser irradiation.

The semiconductor layers are deposited onto a metal film in a vacuum process -- for example PECVD or sputtering. If necessary, several layers are processed one after another to increase the material thickness. The initially compact layer generated this way is broken up by local laser irradiation, which finally results in a micro-stabilized porous silicon layer.

In addition, doped areas can be created in the silicon layer by local laser irradiation. Especially p-doped areas on a n-doped semiconductor layer function as reinforcement areas since they store fewer lithium ions than the n-doped areas. This prevents swelling and increases the mechanical stability of the anode.

The laser processed film is then metalized and contacted. With this process, a battery with a large share of active material and a high energy density can be manufactured easily and cost-effectively.

The second process was developed by the Institute for Material Sciences at the University of Stuttgart (Prof. Dr. Guido Schmitz, and formerly Prof. Dr. Horst Strunk); To solve the problem of the mechanical loading of a silicon anode on a Li-ion rechargeable battery, the scientists developed nano-architechtured silicon films that demonstrates great mechanical resilience even in case of several hundred charge cycles. These silicon anodes can be produced in a continuous process.

To achieve this special structure, the bulk silicon layer was coated on an electrically-conductive substrate, e.g. a metal film or a conductive polymer film, . Then, another layer that contains aluminum is applied. After an optimized heat treatment a partial interdiffusion takes place in this bilayer system. The semiconductor transits, at least partially, to the crystalline state.

In the final step, parts of the metal coating on the surface are removed using a wet chemical process. Moreover a conformal aluminum-oxide functional layer forms spontaneously on the nanostructured porous silicon layer, which provides the anode material in a Li-ion rechargeable battery with great stability.

Initial experiments with the laboratory model of a Li-ion rechargeable battery have already shown that the capacity without further optimizations remained stable even after 500 charge cycles at approx. 1650mAh/g; this is more than four times the normal value for today's lithium-ion rechargeable batteries with graphite anodes.

The patents for these inventions were registered in Europe and the USA and are pending. Technologie-Lizenz-Büro (TLB) GmbH supports the University of Stuttgart in patenting and marketing its innovations. Acting on behalf of the University, TLB is in charge of the commercial implementation of these future-orientated technologies on a global level and offers companies opportunities for cooperation and licensing.
For further information, please contact: Dr.-Ing. Hubert Siller (siller@tlb.de).

Weitere Informationen:

http://www.technologie-lizenz-buero.com
http://www.ipv.uni-stuttgart.de/index.en.html
http://www.uni-stuttgart.de/mawi/index.en.html

Annette Siller | idw - Informationsdienst Wissenschaft

Further reports about: TLB battery energy storage rechargeable battery semiconductor

More articles from Power and Electrical Engineering:

nachricht Improved stability of plastic light-emitting diodes
19.04.2018 | Max-Planck-Institut für Polymerforschung

nachricht Intelligent components for the power grid of the future
18.04.2018 | Christian-Albrechts-Universität zu Kiel

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: Molecules Brilliantly Illuminated

Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.

Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Structured light and nanomaterials open new ways to tailor light at the nanoscale

23.04.2018 | Physics and Astronomy

On the shape of the 'petal' for the dissipation curve

23.04.2018 | Physics and Astronomy

Clean and Efficient – Fraunhofer ISE Presents Hydrogen Technologies at the HANNOVER MESSE 2018

23.04.2018 | Trade Fair News

VideoLinks
Science & Research
Overview of more VideoLinks >>>