Enhancing Supercapacitive Swing Adsorption of CO2 with Advanced Activated Carbon Electrodes

Abstract

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 absorb and desorb CO2 highly selectively and reversibly. However, thus far SSA only showed low sorption capacity, and slow sorption kinetics. Herein, it is shown that the sorption capacity can be substantially increased via the use of carbons with a higher specific capacitance. The highest gravimetric sorption capacity is 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 are 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.