Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

SRNL research paves way for portable power systems

10.01.2012
Developments by hydrogen researchers at the U.S. Department of Energy's (DOE) Savannah River National Laboratory (SRNL) are paving the way for the successful development of portable power systems with capacities that far exceed the best batteries available today. SRNL's advances in the use of alane, a lightweight material for storing hydrogen, may be the key that unlocks the development of portable fuel cell systems that meet the needs for both military and commercial portable power applications.

SRNL has demonstrated a practical path to portable power systems based on alane and similar high capacity hydrogen storage materials that provide the sought-after high specific energy, which means the amount of energy per weight. Their accomplishments to date include developing a lower-cost method of producing alane, developing a method to dramatically increase the amount of hydrogen it releases, and demonstrating a working system powering a 150 W fuel cell.

Portable power equipment manufacturers are looking for systems that can provide specific energies greater than 1000 watt-hours per kilogram (Wh/kg); that's more than 2 to 3 times the capacity of the best primary lithium batteries today. "Higher specific energy means more energy per weight," said SRNL's Dr. Ted Motyka. "The goal is to provide sufficient energy to a system that is light enough to be carried by a soldier or used in unmanned aircraft and other applications where weight is a factor."

Hydrogen, at 33,000 Wh/kg, has the highest specific energy of any fuel, so it is a natural candidate to fuel such high-capacity systems. The challenge, however, has been developing a material for storing hydrogen with both the high capacity and the low weight needed for portable systems.

SRNL has been working for years on developing several light-weight, high capacity solid-state hydrogen storage materials for automotive applications. While most of these materials do not meet all the various requirements needed for automotive applications, many may be viable for small portable power systems.

One of the most promising materials is aluminum hydride, (AlH3) or alane. Alane, while not a new material, has only in the last few years been considered as a hydrogen storage material for fuel cell applications. SRNL researchers are among only a handful of researchers, worldwide, currently working with alane and beginning to unwrap its material and engineering properties.

Dr. Motyka, Dr. Ragaiy Zidan and Dr. Kit Heung, all of SRNL, led a team to characterize and optimize alane as a hydrogen storage material, develop a small hydrogen storage vessel containing alane, and demonstrate hydrogen release at delivery rates suitable for powering small commercial fuel cells. The results of that work are attracting interest from several commercial companies working in the area of portable power systems.

Alane is one of the classes of materials known as chemical hydrogen storage materials. Like metal hydrides, chemical hydrogen storage materials provide a solid-state storage medium for hydrogen. Unlike metal hydrides, however, chemical hydrogen storage materials, like alane, do not readily reabsorb hydrogen, so once their hydrogen is released the material must be chemically reprocessed to restore its hydrogen. An advantage of alane is its very high hydrogen capacities; it can store twice as much hydrogen, in the same volume, as liquid hydrogen, and can do so at the very high gravimetric capacity of 10 wt%. Alane also exhibits very favorable discharge conditions, making it one of the ideal chemical hydrogen storage materials.

Among the biggest challenges the team addressed were the limited amount of readily available commercial alane, and its high cost to produce – which could be significant impediments to widespread use. As part of this project, they initially developed a bench-scale system to produce the quantities of alane needed for experimental and optimization studies. This work led to the development of a new and potentially lower cost process for producing alane. "Our process overcomes some of the handicaps of traditional methods for producing alane," says Dr. Zidan. "This novel method minimizes the use of solvents, and is able to produce pure, halide-free alane."

Work led by Dr. Zidan also resulted in a process to increase the amount of hydrogen that can be extracted from alane. This two-step process was found to double the amount of hydrogen that can be liberated from alane using a traditional one-step process.

A major part of this project was to evaluate alane systems for compatibility with small fuel cell applications. Preliminary results on a proof-of-concept vessel containing approximately 22 grams of alane showed that the system could scale nicely to meet the required hydrogen release rate for a small 100-watt fuel cell system. Based on those results a larger system containing 240 grams of alane was designed, fabricated and tested with a 150 watt commercial fuel cell. The results show that the system was able to operate the fuel cell at near full power for over three hours and at reduced power for several more hours.

Work to date was funded under SRNL's Laboratory Directed Research & Development program, which supports highly innovative and exploratory research aligned with the Laboratory's priorities. The success achieved so far has attracted additional funding from the DOE's Fuel Cell Technologies Program in the Office of Energy Efficiency & Renewable Energy, along with interest from commercial firms.

SRNL is DOE's applied research and development national laboratory at SRS. SRNL puts science to work to support DOE and the nation in the areas of environmental stewardship, national security, and clean energy. The management and operating contractor for SRS and SRNL is Savannah River Nuclear Solutions, LLC.

Angeline French | EurekAlert!
Further information:
http://srnl.doe.gov/

More articles from Power and Electrical Engineering:

nachricht Researchers measure near-perfect performance in low-cost semiconductors
18.03.2019 | Stanford University

nachricht Robot arms with the flexibility of an elephant’s trunk
18.03.2019 | Universität des Saarlandes

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: The taming of the light screw

DESY and MPSD scientists create high-order harmonics from solids with controlled polarization states, taking advantage of both crystal symmetry and attosecond electronic dynamics. The newly demonstrated technique might find intriguing applications in petahertz electronics and for spectroscopic studies of novel quantum materials.

The nonlinear process of high-order harmonic generation (HHG) in gases is one of the cornerstones of attosecond science (an attosecond is a billionth of a...

Im Focus: Magnetic micro-boats

Nano- and microtechnology are promising candidates not only for medical applications such as drug delivery but also for the creation of little robots or flexible integrated sensors. Scientists from the Max Planck Institute for Polymer Research (MPI-P) have created magnetic microparticles, with a newly developed method, that could pave the way for building micro-motors or guiding drugs in the human body to a target, like a tumor. The preparation of such structures as well as their remote-control can be regulated using magnetic fields and therefore can find application in an array of domains.

The magnetic properties of a material control how this material responds to the presence of a magnetic field. Iron oxide is the main component of rust but also...

Im Focus: Self-healing coating made of corn starch makes small scratches disappear through heat

Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again.

Superficial micro-scratches on the car body or on other high-gloss surfaces are harmless, but annoying. Especially in the luxury segment such surfaces are...

Im Focus: Stellar cartography

The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.

A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...

Im Focus: Heading towards a tsunami of light

Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.

"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

Laser processing is a matter for the head – LZH at the Hannover Messe 2019

25.03.2019 | Trade Fair News

A Varied Menu

25.03.2019 | Life Sciences

‘Time Machine’ heralds new era

25.03.2019 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>