Fuel cells and game-changing tech to remove 99% of carbon dioxide from
air

Date:
February 3, 2022
Source:
University of Delaware
Summary:
Engineers have demonstrated a way to effectively capture 99%
of carbon dioxide from air using a novel electrochemical system
powered by hydrogen.



FULL STORY ========================================================================== University of Delaware engineers have demonstrated a way to effectively
capture 99% of carbon dioxide from air using a novel electrochemical
system powered by hydrogen.


==========================================================================
It is a significant advance for carbon dioxide capture and could bring
more environmentally friendly fuel cells closer to market.

The research team, led by UD Professor Yushan Yan, reported their method
in Nature Energy on Thursday, February 3.

Game-changing tech for fuel cell efficiency Fuel cells work by converting
fuel chemical energy directly into electricity.

They can be used in transportation for things like hybrid or zero-emission vehicles.

Yan, Henry Belin du Pont Chair of Chemical and Biomolecular Engineering,
has been working for some time to improve hydroxide exchange membrane
(HEM) fuel cells, an economical and environmentally friendly alternative
to traditional acid-based fuel cells used today.



==========================================================================
But HEM fuel cells have a shortcoming that has kept them off the road --
they are extremely sensitive to carbon dioxide in the air. Essentially,
the carbon dioxide makes it hard for a HEM fuel cell to breathe.

This defect quickly reduces the fuel cell's performance and efficiency by
up to 20%, rendering the fuel cell no better than a gasoline engine. Yan's research group has been searching for a workaround for this carbon
dioxide conundrum for over 15 years.

A few years back, the researchers realized this disadvantage might
actually be a solution -- for carbon dioxide removal.

"Once we dug into the mechanism, 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," said Brian Setzler, assistant professor for research in chemical and biomolecular engineering
and paper co- author.

While this isn't good for the fuel cell, the team knew if they could
leverage this built-in "self-purging" process in a separate device
upstream from the fuel cell stack, they could turn it into a carbon
dioxide separator.



==========================================================================
"It turns out our approach is very effective. We can capture 99% of the
carbon dioxide out of the air in one pass if we have the right design
and right configuration," said Yan.

So, how did they do it? They found a way to embed the power source
for the electrochemical technology inside the separation membrane. The
approach involved internally short- circuiting the device.

"It's risky, but we managed to control this short-circuited fuel cell
by hydrogen. And by using this internal electrically shorted membrane,
we were able to get rid of the bulky components, such as bipolar plates, current collectors or any electrical wires typically found in a fuel
cell stack," said Lin Shi, a doctoral candidate in the Yan group and
the paper's lead author.

Now, the research team had an electrochemical device that looked like a
normal filtration membrane made for separating out gases, but with the capability to continuously pick up minute amounts of carbon dioxide from
the air like a more complicated electrochemical system.

In effect, embedding the device's wires inside the membrane created
a short-cut that made it easier for the carbon dioxide particles to
travel from one side to the other. It also enabled the team to construct
a compact, spiral module with a large surface area in a small volume. In
other words, they now have a smaller package capable of filtering greater quantities of air at a time, making it both effective and cost-effective
for fuel cell applications. Meanwhile, fewer components mean less cost
and, more importantly, provided a way to easily scale up for the market.

The research team's results showed that an electrochemical cell measuring
2 inches by 2 inches could continuously remove about 99% of the carbon
dioxide found in air flowing at a rate of approximately two liters per
minute. An early prototype spiral device about the size of a 12-ounce
soda can is capable of filtering 10 liters of air per minute and scrubbing
out 98% of the carbon dioxide, the researchers said.

Scaled for an automotive application, the device would be roughly the
size of a gallon of milk, Setzer said, but the device could be used
to remove carbon dioxide elsewhere, too. For example, the UD-patented technology could enable lighter, more efficient carbon dioxide removal
devices in spacecraft or submarines, where ongoing filtration is critical.

"We have some ideas for a long-term roadmap that can really help us get
there," said Setzler.

According to Shi, since the electrochemical system is powered by hydrogen,
as the hydrogen economy develops, this electrochemical device could also
be used in airplanes and buildings where air recirculation is desired as
an energy- saving measure. Later this month, following his dissertation defense, Shi will join Versogen, a UD spinoff company founded by Yan,
to continue advancing research toward sustainable green hydrogen.

Co-authors on the paper from the Yan lab include Yun Zhao, co-first author
and research associate, who performed experimental work essential for
testing the device; Stephanie Matz, a doctoral student who contributed
to the designing and fabrication of the spiral module, and Shimshon
Gottesfeld, an adjunct professor of chemical and biomolecular engineering
at UD. Gottesfeld was principal investigator on the 2019 project, funded
by the Advanced Research Projects Agency-Energy (ARPA-E), that led to
the findings.

========================================================================== Story Source: Materials provided by University_of_Delaware. Original
written by Karen B.

Roberts. Note: Content may be edited for style and length.


========================================================================== Related Multimedia:
* Moving_closer_to_environmentally_friendly_fuel_cells ========================================================================== Journal Reference:
1. Lin Shi, Yun Zhao, Stephanie Matz, Shimshon Gottesfeld, Brian
P. Setzler,
Yushan Yan. A shorted membrane electrochemical cell powered
by hydrogen to remove CO2 from the air feed of hydroxide
exchange membrane fuel cells. Nature Energy, 2022; DOI:
10.1038/s41560-021-00969-5 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/02/220203161122.htm

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