Army researchers develop novel nanogalvanic alloys for on-demand hydrogen generation (US)

Army researchers have developed a novel, structurally-stable, aluminum-based nanogalvanic alloy powder that, when combined with water or any water-based liquid, reacts to produce on-demand hydrogen for power generation at room temperature without chemicals, catalysts or externally supplied power. These patent-pending powders produce hydrogen at a rate that currently is one of the fastest reported for Al and water reactions without the need of hazardous and costly materials or additional processes. The reaction results in the production of hydrogen and heat with only inert residual materials; i.e., no toxic by-products. ARL has demonstrated that hydrolysis will occur with virtually any water containing liquid. It has long been known that aluminum (Al) reacts with water to produce hydrogen gas and aluminum oxide via a hydrolysis reaction. Aluminum metal oxidizes when in contact with water, rapidly producing a passivating oxide layer which prevents the hydrolysis reaction (H2). Further, hydrolysis to evolve H2 can only occur if the native oxide layer is actively removed. This is usually achieved by adding hazardous corrosive compounds (caustic soda, hydrochloric acid, etc.) which dissolve in water, toxic and expensive metals (such as gallium, platinum, etc.), or by forcing the reaction by additional external energy (electric current and/or superheated steam).

Arl1

Source: ARL.

This powder-based alloy includes material that disrupts the formation of an encapsulating aluminum oxide layer, allowing for the continuous production of hydrogen that can be used at the point of need to power a wide range of devices via fuel cells and internal combustion.

The powder can be easily manufactured to scale, and can be conveniently and safely transported via tablets or vacuum pouches, thus eliminating reliance on high-pressure hydrogen cylinders.

—Dr. Anit Giri, a scientist with the lab‘s Weapons and Materials Research Directorate

ARL will post a Federal Register Notice and launch a supporting website inviting companies to submit their ideas on how best to commercialize this technology. The laboratory will then select the most appropriate partners and collaborators. Officials said license exclusivity will then be determined.

The researchers said the powders has many advantages, such as:

  • Energy and Power Source
  • Stable Alloy Powder
  • Non-Toxic
  • Environmentally Friendly
  • Hydrogen Emitting
  • Manufacture to Scale
  • Easily Transportable

Army researchers discovered the unique properties of the nanopowder while investigating aluminum alloy compositions for other purposes. The researchers, from the lab’s Lightweight and Specialty Metals Branch, made the serendipitous discovery that at least one of these compositions can, in the presence of water, spontaneously generate hydrogen, rapidly and efficiently.

The researchers have since demonstrated rapid hydrogen generation rates using powder and tablet forms of the alloy. The hydrogen has been shown to be useful for powering fuel cells and is expected to power internal combustion engines.

—Branch Chief Robert Dowding

The researchers are currently taking advantage of the innovation by characterizing the hydrogen generation rates and purity of the gas generated, Dowding said.

They are also examining the effects of compositional changes to the alloy and systematic changes in the microstructure of the powders, he said.

Giri said the discovery has many benefits and applications, such as simple manufacturing.

The powder can be made using current manufacturing techniques from either pure or alloyed aluminum. The manufacturing process is easily scalable and it is also very fast—with a 75% theoretical hydrogen yield in one minute at standard temperature and pressure, and 100% theoretical yield in three minutes.

—Dr. Giri

The nanopowder is also extremely efficient. Giri said 1 kg of powder can generate 4.4 kWh of energy. The material can be in powder or tablet form and be combined with any available water-based liquid to provide hydrogen on demand, at the point of need.

The discovery eliminates reliance on high-pressure cylinders, Giri said.

It’s easy to transport and store via tablets or vacuum-sealed pouches with no inherent inhalation risk. The powder is also environmentally friendly. Its by-products are stable and non-toxic. Finally it’s a versatile hydrogen source with direct combustion for vehicular power, to use in fuel cells to power any electronic device, and could potentially be used in 3-D printing/additive manufacturing to create self-cannibalizing robots/drones.

—Dr. Giri

In order to support a better understanding of the material, the laboratory established a website to showcase details on the technology and a review the process that will culminate in the granting of a patent license(s) around September 2018.

On this website, visitors can register their interest to be contacted about further developments, post general questions and download background technical information, as well as templates for all the required documents that will be used throughout the process.

Source :

http://www.greencarcongress.com/2018/06/20180624-arl.html

Posted in Research and development.

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