Fuel cells developed for increased airplane efficiency

Researchers have developed the first fuel cell that can directly convert fuels, such as jet fuel or gasoline, to electricity, providing a more energy-efficient way to create electric power for planes or cars.
Scientists led by Professor Su Ha and Professor M Grant Norton at Washington State University have made coin-sized fuel cells to prove the concept and plan to scale it up.
About 10 years ago, the researchers began developing a solid-oxide fuel cell to provide electrical power on commercial airplanes.
Fuel cells offer a clean and highly efficient way to convert the chemical energy in fuels into electrical energy.

In addition to increasing fuel efficiency and reducing emissions of harmful pollutants, fuel cells are quiet and would be particularly helpful when a plane is at a gate and the main jet engines are turned off.
A solid-oxide fuel cell is similar to a battery in that it has an anode, cathode, and electrolyte and creates electricity. But it uses fuel to create a continuous flow of electricity.

The process could be approximately four times more efficient than a combustion engine because it is based on an electrochemical reaction.
The solid-oxide fuel cell is different from other fuels cells in that it is made of solid materials, and the electricity is created by oxygen ions traveling through the fuel cell.

To avoid the added weight of a device that converts the complex fuel into simpler components, such as hydrogen and carbon monoxide (a mixture called synthesis gas) the researchers wanted to be able to directly feed the liquid fuel into the fuel cell.
Furthermore, they had to overcome the problems of sulfur poisoning and coking, a process in which a solid product is created from imperfect combustion. Sulfur is present in all fossil-based fuels and can quickly deactivate fuel cells.
Using a unique catalyst material and a novel processing technique, Ha, Norton and collaborators at Kyung Hee University in South Korea and the Boeing Company in Seattle have produced a high-performance fuel cell that operates when directly fed with a jet fuel surrogate.

"The results of this research are a key step in the integration of fuel cell technology in aviation and the development of the more electric airplane," said Joe Breit, associate technical fellow at Boeing and a participating researcher on the project.
The researchers envision integrating their fuel cell with a battery to power auxiliary power units.