Engineers have proved that an unique electrochemical device fueled by hydrogen can successfully absorb 99 percent of carbon dioxide from the air.
Engineers at the University of Delaware have proved that an unique electrochemical device fueled by hydrogen can successfully absorb 99 percent of carbon dioxide from the air.
It’s a big step forward for carbon capture, and it might help bring more ecologically friendly fuel cells to market.
On Thursday, February 3, the study team, lead by UD Professor Yushan Yan, published their findings in Nature Energy.
Technology that will revolutionize fuel cell efficiency
Fuel cells function by directly turning chemical energy from the fuel into electricity. They may be utilized in transportation for cars that are either hybrid or zero-emission.
Yan, the Henry Belin du Pont Chair of Chemical and Biomolecular Engineering, has been researching on improving hydroxide exchange membrane (HEM) fuel cells, which are a cost-effective and ecologically benign alternative to today’s acid-based fuel cells.
However, one flaw of HEM fuel cells has kept them off the road: they are particularly sensitive to carbon dioxide in the air. Carbon dioxide, in essence, makes it difficult for a HEM fuel cell to breathe.
This flaw affects the performance and efficiency of the fuel cell by up to 20%, thereby making it no better than a gasoline engine. For more than 15 years, Yan’s research group has been looking for a solution to the carbon dioxide problem.
Researchers noticed a few years ago that this disadvantage may really be a solution for carbon dioxide removal.
“We realized the fuel cells were capturing just about every bit of carbon dioxide that came into them, and they were really good at separating it to the other side once we dug into the mechanism,” said Brian Setzler, assistant professor for research in chemical and biomolecular engineering and paper co-author.
While this is bad for the fuel cell, the researchers realized that if they could use this built-in “self-purging” mechanism in a separate device upstream from the fuel cell stack, it might be used as a carbon dioxide separator.
“Our strategy has proven to be quite successful. If we have the correct design and setup, we can collect 99 percent of carbon dioxide from the air in one pass “ration,” Yan said.
So, how did they manage to achieve it?
They discovered a technique to integrate the electrochemical technology’s power source inside the separation membrane. Internally short-circuiting the device was the method used.
“It was dangerous, but we were able to use hydrogen to regulate this short-circuited fuel cell. We were also able to eliminate the bulky components present in a fuel cell stack, such as bipolar plates, current collectors, and any electrical connections, by employing an internal electrically shorted membrane “Lin Shi, a PhD student in Yan’s department and the paper’s main author, agreed.
The study team now had an electrochemical device that resembled a standard filtration membrane for separating gases, but could continually suck up minute quantities of carbon dioxide from the air, similar to a more intricate electrochemical system.
The device’s wires were embedded within the membrane, thereby creating a shortcut for carbon dioxide particles to go from one side to the other. It also allowed the team to create a small-volume, helical module with a big surface area. In other words, they now have a smaller container that can filter more air at once, making it both efficient and cost-effective for fuel cell applications. In the meanwhile, fewer components meant lower costs and, more significantly, a simple method to scale up for the market.
According to the findings, a two-inch-by-two-inch electrochemical cell could constantly remove around 99 percent of the carbon dioxide contained in air moving at a rate of roughly two liters per minute. According to the researchers, an early prototype spiral device the size of a 12-ounce soda can is capable of filtering 10 liters of air per minute and removing 98 percent of carbon dioxide.
The gadget, if scaled for an automobile use, would be around the size of a gallon of milk, according to Setzer, but it could also be used to remove carbon dioxide elsewhere. The UD-patented technique, for example, might allow for lighter, more effective carbon dioxide removal equipment in spaceships or submarines where continuous filtering is required.
“We have some long-term roadmap ideas that can really help us get there,” Setzler added.
According to Shi, since the electrochemical system is fueled by hydrogen, this electrochemical device might be employed in aircraft and buildings where air recirculation is needed as an energy-saving solution as the hydrogen economy develops. Shi will join Versogen, a UD spinoff business formed by Yan, to pursue research on sustainable green hydrogen later this month, after his dissertation defense.
Yun Zhao, co-first author and research associate, who performed crucial experimental work for testing the device; Stephanie Matz, a doctoral student who helped design and fabricate the spiral module; and Shimshon Gottesfeld, an adjunct professor of chemical and biomolecular engineering at UD, are all co-authors on the paper from the Yan lab. Gottesfeld was the primary investigator on the 2019 research that resulted to the discoveries, which was financed by the Advanced Research Projects Agency-Energy (ARPA-E).
