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New device captures carbon dioxide by pumping it across a battery
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- DeepHorus
Researchers at the University of Delaware demonstrated a battery technique that captures carbon dioxide and pumps it across a cell. Led by James Buchen, the team says the electrochemical method could use less energyâand cost lessâthan reversible-filter systems. That could lower carbon-capture costs.
Conventional carbon-capture equipment usually operates like a reversible filter. Air passes through granules or a liquid that absorbs CO2, and the loaded material is then generally heated. The released gas is collected as a separate, concentrated CO2 stream.
Inside the new cell, hydroxide produced at the cathode reacts with CO2, creating carbonate or bicarbonate. Those products cross the separator membrane toward the anode. There, lower pH reverses the reaction, turning carbonate back into carbon dioxide gas.
Both electrodes are nickel hydroxide, the material used in cathodes of older rechargeable AA and AAA nickel-metal hydride batteries. The device is not chiefly storing energy for a mobile device. It functions instead like a chemical seesaw.
Applying voltage in one direction drives the cathode to produce hydroxide and moves the reaction toward the anode. Reversing the voltage makes the former anode the new cathode, running the same chemistry backward. During the cycle, the cell captures and transports CO2.
The moving-electrode process distinguishes the design from filters that heat CO2-loaded material to release gas. Buchenâs team calls the battery approach more viable than previous attempts. If its energy savings hold, capture could become cheaper than filter-based designs.
Established nickel-metal hydride battery chemistry allows the electrodes to alternate roles. Carbon dioxide is taken up on one side and released on the other as the chemistry reverses. The concept could offer a lower-energy route to capture if its projected advantages hold at practical scale.
