Demonstrated a way that effectively remove CO2 using a new hydrogen-powered electrochemical system.
Engineers at the University of Delaware in the United States have demonstrated a way to remove 99% of carbon dioxide from the air. The completely fortuitous discovery came about while the researchers were trying to improve a fuel cell-based energy conversion system. The study was published in Nature Energy.
A precious mistake
The team of researchers, led by Professor Yushan Yan, had been working for some time to improve HEM (hydroxide exchange membrane) fuel cells, a cost-effective and environmentally friendly alternative to the traditional acid-based fuel cells used today. HEM fuel cells, unfortunately, have a flaw that has kept them out of the market. They are extremely sensitive to carbon dioxide in the air. Essentially, carbon dioxide makes it difficult for this type of cell to breathe and quickly reduces performance and efficiency by up to 20%. No better than a gasoline engine. Engineers had been searching for an alternative solution to this problem for over 15 years. But a few years ago they realized that this drawback could become a solution for removing carbon dioxide.
Intuition took shape
Hence the idea of creating an ad hoc tool. So Yan’s group found a way to incorporate the power source for the electrochemical technology inside the separation membrane. The approach involved short-circuiting the device internally.
“It’s risky, but we were able to control this fuel cell by short-circuiting the hydrogen. And by using this electrically shorted inner membrane, we were able to eliminate bulky components, such as bipolar plates, current collectors or any electrical wires that are typically found in a fuel cell stack”
Lin Shi
said Lin Shi, a doctoral student on Yan’s team and lead author of the paper.
At this point, the research team had an electrochemical device that looked like a normal filtration membrane made to separate gases. But with the precious ability to continuously collect small amounts of carbon dioxide from the air.
A discovery in the process of being perfected
Results showed that an electrochemical cell measuring 2 inches by 2 inches could continuously remove about 99 percent of the CO2 in air flowing at a rate of about two liters per minute. An early prototype spiral device made, weighing about 340 grams, is, for example, capable of filtering 10 liters of air per minute while capturing 98 percent of the carbon dioxide.
According to the scientists, the technology could be scaled up for an automotive application and also allow for lighter and more efficient CO2 removal devices in space vehicles or submarines, where continuous filtration is critical. In addition, because the electrochemical system is powered by hydrogen, as that market develops, the device could also be used in aircraft and buildings where air recirculation can function as an energy-saving measure.
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