Efficient Co2 Capture from Flue Gases Achieving by an Electrochemical Reactor with Porous Solid-State Electrolyte

Abstract

CO2 capture from flue gases of power plants and chemical industries is an appealing method to control atmospheric CO2 concentrations. Recently, electrochemical carbon capture technologies have attracted much attention due to their mild conditions for capture, ease for fitting with renewable energy sources, and flexibility to meet various operation demands. However, electrochemical carbon capture technologies are presently either energy intensive or have low capture rates. Here, we report a method that uses an electrochemical reactor with porous solid-state electrolytes (PSEs) for CO2 capture, resulting in high capture rates while consuming less energy. Hydrogen oxidation reaction (HOR) and hydrogen evolution reaction are performed on reactor’s anode and cathode, respectively, to lower its thermodynamic loss while keeping stoichiometric balance, and the PSE is used to prevent water flooding on the HOR anode, which is beneficial for increasing the capture current density. Under realistic flue gases, our method has been demonstrated to reach a current density of ~100 mA/cm2 at 1.6 V, corresponding to a CO2 capture rate of ~5 ml/min (4 cm2 of cathode) with 213 kJ/mol CO2. These results are superior than current electrochemical capture methods. A techno-economic analysis further suggests that our method costs $38.0-84.6 per ton of captured CO2, which is very competitive compared to the industry application requirement of $100-150 per ton of CO2.

Keywords: electrochemical CO2 capture, flue gas, porous solid-state electrolyte, high current density, Techno-economic analysis