WPI professor part of nationwide push for clean energy

In 1842, Welsh scientist William Grove invented the first hydrogen fuel cell, which generated electricity with only water as a byproduct. 

Sounds like just what we need, right? The climate crisis demands clean energy, and it seems like the solution has been with us for over a century and a half. Unfortunately, if it’s too good to be true, it usually is. As an energy source, hydrogen is just too expensive to use. 

“Hydrogen is the cleanest fuel possible right now, but the cost is the issue,” said Yu Zhong, associate professor of Mechanical Engineering at Worcester Polytechnic Institute.

Zhong and his team have received a $999,973 grant to iron out the kinks in the process of using hydrogen as a clean fuel. The WPI project is one of only 12 nationwide that has been funded by the U.S. Department of Energy. The grant is part of a larger initiative by the DOE to improve the production, storage and transportation of hydrogen as a fuel and as a means to reduce carbon emissions. 

Our world runs on the products of fossil fuels, and the use of those is the largest source of carbon emissions by far. While it is clear that climate change must be addressed with radical change, we can’t live without fuel. It seems like a catch-22 but if Zhong has anything to say about the matter, cost-effective clean fuel generation may well be within reach. 

Hydrogen is produced from a chemical reaction that breaks down water molecules into its oxygen and hydrogen components. Zhong has been contemplating a solution to make it more cost effective for about 20 years, when he started working on solid oxygen fuel cells before moving to electrolysis cells.

Along with the primary cost barrier, electrolysis, which is the use of an electrical current to drive a chemical reaction, is the key component in this process, and it is most often used in the separation of elements. The use of electricity generated by solar or wind power allows hydrogen production to be powered by renewable sources. 

However, the Solid Oxygen Electrolysis Cells, or SOECs, have a lifetime of one to five years before they must be replaced, as the oxygen electrodes in the SOECs rapidly degrade due to chromium poisoning. The frequent replacement of SOECs makes this method not worth the investment necessary for large-scale hydrogen production. 

The key, said Zhong, is elongating that process and correspondingly lowering the hydrogen production cost. To do so, the DOE is funding projects that will build oxygen electrodes more resistant to chromium poisoning. “The DOE is really working to embrace a hydrogen society,” said Zhong.

SOECs operate in large stacks, each separated by an interconnecter of stainless steel, which contains chromium. The oxygen electrodes are the active material that will drive the chemical reaction to produce hydrogen. To continue this reaction, the electrodes must retain their electrical conductivity and must remain stable. At high temperatures, the chromium in the steel is released and as chromium levels increase, it reacts with the electrodes instead, reducing the SOECs performance. 

Through computer modelling and laboratory experiments, Zhong’s team hopes to design entirely new materials for oxygen electrodes, which are currently ceramic based. “We have proved that the classic materials have issues so we want to propose some totally new materials,” said Zhong, which will be different down to the microstructure. 

The current goal is to extend the lifespan of SOECs to10 to 15 years but hopefully as much as 25 to 30. However, the development progress is not measured in terms of years but in percentage degradation per a thousand hours. The target measure, said Zhong, is 0.4%, quite a ways down from where it can easily go into the double digits. 

The project will go for two years, after which, results will be given to a local industry partner, Saint-Gobain Research North America in Northborough. For Zhong, the project represents breaking the cost barrier for the ultimate renewable energy source — one that can be drawn from the air itself. “As long as you have oxygen, you have hydrogen.”