Reduced oxygen nanocrystalline materials show improved…

Reduced oxygen nanocrystalline materials show improved performance

Researchers at the University of Connecticut have found that reducing oxygen in some nanocrystalline materials may improve their strength and durability at elevated temperatures, a promising enhancement that could lead to better biosensors, faster jet engines, and greater capacity semiconductors.

“Stabilizing nanocrystals at elevated temperatures is a common challenge,” says Peiman Shahbeigi-Roodposhti, a postdoctoral research scholar with UConn’s Institute of Materials Science and the study’s lead author. “In certain alloys, we found that high levels of oxygen can lead to a significant reduction in their efficiency.”

Using a special milling process in an enclosed glove box filled with argon gas, UConn scientists, working in collaboration with researchers from North Carolina State University, were able to synthesize nano-sized crystals of Iron-Chromium and Iron-Chromium-Hafnium with oxygen levels as low as 0.01 percent. These nearly oxygen-free alloy powders appeared to be much more stable than their commercial counterparts with higher oxygen content at elevated temperatures and under high levels of stress.

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Nanomaterial helps store solar energy: Efficiently and…

Nanomaterial helps store solar energy: Efficiently and inexpensively

Efficient storage technologies are necessary if solar and wind energy is to help satisfy increased energy demands. One important approach is storage in the form of hydrogen extracted from water using solar or wind energy. This process takes place in a so-called electrolyser. Thanks to a new material developed by researchers at the Paul Scherrer Institute PSI and Empa, these devices are likely to become cheaper and more efficient in the future. The material in question works as a catalyst accelerating the splitting of water molecules: the first step in the production of hydrogen. Researchers also showed that this new material can be reliably produced in large quantities and demonstrated its performance capability within a technical electrolysis cell – the main component of an electrolyser. The results of their research have been published in the current edition of the scientific journal Nature Materials.

Since solar and wind energy is not always available, it will only contribute significantly to meeting energy demands once a reliable storage method has been developed. One promising approach to this problem is storage in the form of hydrogen. This process requires an electrolyser, which uses electricity generated by solar or wind energy to split water into hydrogen and oxygen. Hydrogen serves as an energy carrier. It can be stored in tanks and later transformed back into electrical energy with the help of fuel cells. This process can be carried out locally, in places where energy is needed such as domestic residences or fuel cell vehicles, enabling mobility without the emission of CO2.

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5 things you didn’t know about… seawater-drinking batteries

materialsworld:

Credit: Open Water
Power

1. MIT spinout Open Water Power is developing safer, more
efficient batteries for underwater acoustic sensors and unmanned underwater
vehicles (UUVs).

2. The underwater batteries are used for marine research
activities such as ocean floor monitoring, and are currently being used in
collaboration with the US Navy to replace power systems in acoustic sensors
designed to detect submarines.

3. The new battery consists of an aluminium alloy anode and
an alkaline electrolyte, which contains potassium hydroxide.

4. A nickel-alloy cathode splits seawater into hydrogen and
hydroxide ions, which react with the aluminium anode, producing aluminium
hydroxide and free electrons that move back to the cathode, completing the
circuit.

5. In summer 2017, Open Water Power plan as to launch a pilot scheme with
Riptide Autonomous Solutions. It is hoped that Open Water Power can increase
the single journey distance of Riptide’s UUVs by ten times, to 1,000 nautical
miles.

To find out more see page 5 of the upcoming August issue of
Materials World.