Carbon-Capture Device Cuts Greenhouse Gases and Generates Electricity

This electrochemical cell turns carbon dioxide into a valuable product while producing electricity. (Image courtesy of Cornell).

A team of researchers recently developed a novel method of carbon capture, the technology of trapping carbon dioxide before it’s released into the atmosphere. The team has proposed an aluminum/carbon dioxide power cell that captures CO₂ and produces electricity as well as a useful carbon byproduct.

Capturing Carbon Dioxide

Currently, most carbon-capture methods trap emissions in fluids or solids which can be heated or depressurized to release the CO₂. The gas is then compressed to be transported for industrial use or otherwise sequestered underground. As the team points out, these methods are far from perfect.

“One of the roadblocks to adopting current CO₂ capture technology in electric power plants is that the regeneration of the fluids used for capturing CO₂ utilize as much as 25 percent of the energy output of the plant,” said researcher Lynden Archer, a professor of engineering at Cornell University. “This seriously limits the commercial viability of such technology. Additionally, the captured CO₂ must be transported to sites where it can be sequestered or reused, which requires new infrastructure.”

The new method proposed by the team could be a paradigm shift, according to Archer. “The fact that we’ve designed a carbon capture technology that also generates electricity is, in and of itself, important,” he said.

How much electricity are we talking about?

The team reports that their electrochemical cell can generate up to 13 ampere hours per gram of carbon, with a discharge potential around 1.4 V. According to the researchers, this amount of energy is comparable to that of the highest energy-density battery systems.

The cell works by using aluminum as the anode, and a mixture of CO₂ and O₂ as the active ingredients of the cathode. The electrochemical reactions between anode and cathode sequester the CO₂ and produce electricity and a carbon-carbon oxalate byproduct. Since the oxalate is widely used in pharmaceutical and other industries, it’s a valuable bonus to the electrical energy.

“A process able to convert CO₂ into a more reactive molecule such as an oxalate that contains two carbons opens up a cascade of reaction processes that can be used to synthesize a variety of products,” said Archer.

The potential and capacity of the cell are compared using different gas conditions. The 80% CO2 and 20% O2 mixture (black line) obtained the best results. (Image courtesy of Science Advances.)

While there are clear advantages to the team’s proposed cell, their motivation remains the same as always: reduce our carbon footprint. The team believes their research offers a significant advancement towards this goal.

“On the basis of an analysis of the overall CO₂ footprint, which considers emissions associated with the production of the aluminum anode and the CO₂ captured/abated by the Al/CO₂-O₂ electrochemical cell, we conclude that the proposed process offers an important strategy for net reduction of CO₂ emissions,” wrote lead author Wajdi Al Sadat in the team’s paper.

For more on reducing our carbon footprint, read about the $20-million Carbon XPRIZE.