Engineers at the University of Delaware (UD) have demonstrated a way to effectively capture 99% of carbon dioxide from the air using a new electrochemical system powered by hydrogen.
This is a very important step in removing CO2, and could bring the market for greener fuel cells closer. Professor's group Yushan Yan just published this new technique yesterday in Nature Energy.
Fuel cell technology with revolutionary efficiency, or mechanism for removing CO2?
Fuel cells use chemicals to generate electricity. They can be used in cars that they work with hydrogen or another clean energy source. Yan has long been working to improve hydroxide exchange membrane (HEM) fuel cells, a cost-effective and environmentally friendly solution.
But there's a problem: HEM fuel cells are extremely sensitive to CO2 in the air. Essentially, carbon dioxide makes it difficult for a HEM fuel cell to “breathe,” reducing its performance and efficiency by up to 20%.
How to do? This has been a problem that has been going on for over 15 years.
There is a very important positive "side effect"
A few years ago, researchers realized that this disadvantage could actually be a solution. A solution to remove carbon dioxide.
“When we studied the mechanism better, we realized that the fuel cells were able to capture and remove almost every bit of carbon dioxide that entered them,” he says Brian Setzler, co-author of the paper.
It's not a good thing for the fuel cell, but for a carbon dioxide separator it could be great.
“We have found that our approach is very effective. We can remove 99% of carbon dioxide from the air in just one step with the right setup,” Yan said.
How did they do it?
In summary, scientists were able to incorporate the energy source of electrochemical technology within the separation membrane. It was necessary to “short-circuit” the device internally.
“It was risky, but we managed to control this short-circuited fuel cell using hydrogen. And by using this electrically shorted internal membrane, we were able to eliminate bulky components, such as bipolar plates, current collectors, or any electrical wires typically found in a fuel cell stack,” he says Lin Shi, another of the authors.
The research team's results showed that a 5cm by 5cm (2 inch by 2 inch) electrochemical cell could continuously remove about 99% of the carbon dioxide in the air at a rate of about two liters per minute. An early prototype spiral device the size of a 33cl (12 ounce) can is capable of filtering 10 liters of air per minute and remove 98% of carbon dioxide, the researchers said.
Possible applications to remove CO2
The invention is currently being tested on a small scale in the lab, according to Setzler, and will be scaled up for an automotive application. The device would have very small dimensions and could also be used to remove CO2 elsewhere, for example in airplanes and buildings.
“We have some ideas for a long-term roadmap that can really help us get there,” Setzler said.
Fingers crossed!
