Can hydrogen ever power an engine?

Do hydrogen cars have a future?

The key to the shrunk cell was an improved air flow, report the Honda engineers. The ambient air is now pressed through thin channels by a turbo compressor. As a result, the water vapor that inevitably arises in the fuel cell can no longer condense; the reaction surfaces are no longer blocked. About 50 percent more power and a 20 percent thinner cell are the result, according to Honda.

However, this cannot really convince the buyers. A mere 448 Claritys were sold in the USA from January to September. Market leader Toyota brings it with its Mirai, the "first hydrogen sedan in mass production", only to 1044 copies. The Federal Motor Transport Authority does not even list the registration numbers for hydrogen vehicles. Only 314 fuel cell vehicles are said to have been on German roads at the beginning of the year, reports the trade journal "Automobilwoche" - mainly as test and demonstration vehicles.

The small numbers are also reflected in the price. Toyota's Mirai costs just under 80,000 euros in Germany. Competitor Hyundai charges around 65,000 euros for its ix35, a small fuel cell SUV. The Mercedes GLC F-Cell is expected to cost a little less than 70,000 euros - at a higher price, buyers would no longer receive an environmental bonus with which the federal government wants to stimulate the sale of electric vehicles.

"The technology is still too expensive," explains DLR researcher Friedrich. "As soon as mass production begins, however, significant savings can be expected." However, this only affects the costs for production and for the individual components. A central component of the cell, on the other hand, threatens to become a price driver: platinum. The PEM fuel cell needs the noble metal as a so-called catalyst in order to even set the reaction between hydrogen and oxygen in motion.

In order to use as little of the expensive precious metal as possible, car manufacturers are experimenting with extremely thin platinum layers, less than three millionths of a millimeter thick, which are applied to fibrous nanostructures. However, the whole thing must not be too thin or too filigree. "The less platinum is used, the more sensitive the cell," reports Friedrich. "The platinum can be poisoned, it can be occupied, it can become inactive, it can dissolve." The developers have now reached around 20 grams of platinum for a fuel cell with 100 kilowatts of power. The goal is ten grams - still significantly more than the three grams that are used today in the catalytic converter of a gasoline engine. "If the demand increases, the price can change significantly. That makes platinum a critical resource, even if the platinum content of a fuel cell matches the amount in the exhaust system today," says Friedrich.

The biggest enemy of fuel cells is on the roadside - or not: There are currently just 41 publicly accessible hydrogen filling stations in Germany, six of which are defective. If you want to go from Hamburg to Munich, you have to take a detour via Dortmund at the moment. The next operational petrol station along the A7, actually the direct north-south connection, would only come after W├╝rzburg - too risky for the fuel cell cars. Because if the hydrogen runs low, the journey involuntarily ends at the tow hook.