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The second new material undergoing testing in space is nickel aluminide. It too is an intermetallic – a compound of metals with an ordered structure.
This material is revolutionising hydrogen fuel cells and unlocking their potential as a clean, non-polluting power source. Hydrogen is heralded as a future power source because it produces only water vapour as a by-product – unlike burning fossil fuels, which produces carbon dioxide, a climate-warming gas.
'Alkaline' fuel cell used to power scooters and motorboats.
This type of ‘alkaline’ fuel cell can power anything from mobile phones and laptops to scooters and boats. Inside the fuel cell, hydrogen reacts with oxygen from the atmosphere to produce electricity and water vapour. Nickel aluminide acts as a catalyst, speeding up the reaction.
Nickel aluminide is a highly efficient catalyst. Catalysts speed up chemical reactions. Nickel aluminide speeds up the reaction inside a hydrogen fuel cell by providing a surface for hydrogen to react, producing electricity.
Nickel aluminide does this extremely well because of its ‘spongy’ structure. The surface of the material resembles many tiny spherical particles with gaps in-between. This structure gives it a very large surface area on which the reaction can occur.
Nickel aluminde structure viewed under a microscope
Nickel aluminide viewed under a microscope looks ‘spongy’. Its structure is porous with lots of gaps between the particles.
As more data are gathered from the space experiments, scientists aim to improve further the efficiency of nickel aluminide as a catalyst, leading to better fuel cells. Currently, the best alternative to nickel aluminide as a catalyst is platinum, but its high cost is restricting fuel-cell use. The development of nickel aluminide means that we could one day be using hydrogen fuel cells to power a variety of devices from mobile phones and laptops to motorboats and scooters.
Hydrogen fuel cell used to power an electric scooter
This prototype electric scooter is powered by a hydrogen fuel cell. Electricity is produced in the fuel cell attached to the back of the scooter. This charges a battery which powers the scooter. With a full-sized hydrogen tank the scooter has a range of 125 miles and can reach a top speed of 30 mph. Hydrogen-powered vehicles offer a non-polluting future for transport as they don’t emit greenhouse gases such as carbon dioxide.
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