New device captures carbon dioxide by pumping it across a battery

Equipment to capture carbon dioxide from ambient air or smokestacks generally works through a sort of reversible filter. Air is passed through granules or a liquid that absorbs the CO 2 , then that CO 2 -loaded substance undergoes a process (usually heating) that causes it to let

Equipment to capture carbon dioxide from ambient air or smokestacks generally works through a sort of reversible filter. Air is passed through granules or a liquid that absorbs the CO 2 , then that CO 2 -loaded substance undergoes a process (usually heating) that causes it to let go of all that CO 2 . The resulting gas can be collected in a separated stream.

It’s also possible to do a similar sort of operation on a smaller scale—like inside a battery. A new study from a team led by James Buchen of the University of Delaware demonstrates an example of a battery-based electrochemical carbon-capture technique that they say is more viable than previous attempts. It has the potential to require less energy—and therefore be cheaper—than the reversible-filter designs that currently dominate.

Carbon chemistry The basic idea behind a device of this type is that hydroxide produced at the battery cathode reacts with CO 2 , converting it to carbonate or bicarbonate that passes through the separator membrane to the anode. There, the lower pH causes the reaction to reverse, with carbonate turning back into CO 2 gas. The role of the cathode is to produce hydroxide ions; the role of the anode is to consume them.

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