Cornell University researchers Lynden Archer and Wajdi Al Sadat recently discovered a unique method for capturing the greenhouse gas and converting it to a useful product, while producing electrical energy. This method will help to turn the unwanted carbon dioxide into electricity. These researchers developed an oxygen-assisted aluminum/carbon dioxide power cell which uses electrochemical reactions to both isolate the carbon dioxide and also produce electricity. This research is published in the journal Science Advances.
The proposed cell will use aluminum as the anode and streams of carbon dioxide and oxygen (mixed together) as an active ingredients of the cathode. The electrochemical reactions between the anode and the cathode will sequester the carbon dioxide into carbon-rich compounds, producing electricity during the reaction and a valuable oxalate as a byproduct.
In most of the present carbon-capture models, the carbon is captured in fluids or solids, which are then heated or depressurized to release the carbon dioxide. The concentrated gas then has to be compressed and transported to the point of use or sequestered underground.
With this study a paradigm shift in carbon capture methodology is possible. While emphasizing the importance of the team’s findings, Lynden Archer said, “The fact that we’ve designed a carbon capture technology that also generates electricity is, in and of itself, important. One of the roadblocks to adopting current carbon dioxide capture technology in electric power plants is that the regeneration of the fluids used for capturing carbon dioxide utilizes as much as 25 percent of the energy output of the plant. This seriously limits commercial viability of such technology. Additionally, the captured carbon dioxide must be transported to sites where it can be sequestered or reused, which requires new infrastructure.”
The electrochemical cell developed by this team generated 13-ampere hours per gram of porous carbon (as the cathode) at a discharge potential of around 1.4 volts. This is comparable with an energy produced by the highest energy density battery systems available today. Another important aspect of their findings is the generation of superoxide intermediates, which are formed when the dioxide is reduced at the cathode. This superoxide generated during the process reacts with the normally inert carbon dioxide, forming a carbon-carbon oxalate and this is very widely used substance in many industries such as pharmaceutical, fiber and metal smelting.
While speaking about the day to day usage of the technology Al Sadat said, “This technology in not limited to power-plant applications but it fits really well with onboard capture in vehicles, especially if you think of an internal combustion engine and an auxiliary system that relies on electrical power.”