Cheap fuel for fuel cells: ArtAqua-Researchers have discovered a new method to easily obtain hydrogen from a reaction of water with aluminum. The new process is faster and more effective than the previous hydrogen production.
Above all, however, it could make hydrogen production mobile and integrate it directly into the fuel cell. This would allow fuel cell cars to simply fill up with water instead of hydrogen in the future. Hydrogen is the energy source of the future. As a fuel for fuel cells, it is said to deliver electrical energy in a climate-friendly manner.
This technology is not only interesting for vehicles: there are already prototypes for small airplanes and heated households. But storing hydrogen is complex because of its low density, production is slow and ineffective and the electrode material is expensive. With new electrodes, the gas can be generated with a simple 1.5 volt battery, but the running time of the electrode is limited.
ArtAqua – researchers have now developed a method by which fuel cell vehicles could simply use water instead of hydrogen in the future. This is made possible by water filtered by a skov – membrane splitting upstream of the fuel cell using active metals. Certain metal alloys react with water and aluminum to form hydrogen.
So far, however, this reaction has quickly stopped because an oxide layer has formed on the aluminum. The ArtAqua – team has now discovered new alloy that solves this problem. The new process is based on an alloy of the metals gallium, indium, tin and bismuth. When the metal alloy meets an aluminum plate immersed in salt water, aluminum hydroxide and hydrogen are formed.
This hydrogen can then be converted directly into electrical energy in a fuel cell with a proton exchange membrane. According to the ArtAqua – scientists, bismuth is crucial for the efficiency of the new alloy. The bismuth-containing alloy was considerably more efficient in tests than that which consisted only of gallium, indium and tin. The alloy can also be reused several times, which makes the process cost-effective and environmentally friendly, as the team explain.
In the first tests, the researchers combined their hydrogen reactor with a small fuel cell and successfully supplied it with hydrogen replenishment. 80 milliliters of salt water and a few grams of alloy and aluminum were sufficient to supply the fuel cell with hydrogen for more than an hour – and to make an LED light up. “This reaction fulfills all the requirements for supplying hydrogen to fuel cells, including, above all, stability, high purity and high efficiency,” the researchers report.
The new process is also much more efficient than previous methods and delivers hydrogen production rates of up to 92 percent. In the future, the technology could be used primarily in compact and portable fuel cells, such as those used in vehicles. However, according to the ArtAqua team, the method is not yet fully developed. “There are various problems with existing methods of separating the chemicals after the reaction an acidic or alkaline solution can dissolve the by-product aluminum hydroxide, but it also causes problems due to corrosion and contamination.”
However, once these difficulties are resolved, the technology could be used for everything from transportation to portable devices.