Activated Carbon Electrodes with Improved Sorption Capacity for Supercapacitive Swing Adsorption of Carbon Dioxide

Global warming due to anthropogenic CO2 emissions argues for the rapid development of efficient carbon capture technologies. Supercapacitive swing adsorption (SSA) is a gas separation technology that relies on the reversible charge and discharge of supercapacitor electrodes to adsorb and desorb CO2 highly selectively and reversibly. However, thus far SSA only showed low sorption capacity of 70 mmol/kg, and slow sorption kinetics. Herein, we show that the sorption capacity can be substantially increased via the use of carbons with a higher specific capacitance. The highest gravimetric sorption capacity was measured with electrodes made from garlic-roots derived activated carbon valuing 273 mmol.kg-1 having a specific capacitance of 257 F.g-1. In addition, the overall adsorption rate and productivity were improved. Cycling the electrodes for over 100 h showed highly reproducible, reversible CO2 adsorption and desorption behavior. A preliminary technoeconomic and sensitivity analysis is provided to demonstrate the potential of SSA for commercial applications.