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

30 May 2022, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Global warming due to anthropogenic CO2 emissions demands the rapid development of efficient carbon capture technologies. Supercapacitive swing adsorption (SSA) is a technology that relies on the reversible charge and discharge of supercapacitor electrodes to selectively adsorb and desorb CO2. A current limitation of SSA is the low sorption capacity. Here, we investigate a series of activated carbons derived from biomass, coke, coal, and carbide as electrode materials for SSA. The energetic and adsorptive performance metrics are quantitatively analyzed and their relationship with double layer capacitance, real capacitance, imaginary capacitance, and diffusion resistance is studied. The results show that there is a strong positive correlation between specific capacitance and CO2 adsorption capacity. The highest gravimetric sorption capacity was measured for garlic-root derived activated carbons valuing 273 for 4 cm2 electrodes having a specific capacitance of 257 F.g-1. This is a ~4-fold increase compared to BPL 4x6 carbon having a specific capacitance of 86 F.g-1 and an adsorption capacity of 70 mmol.Kg-1. Volumetric specific capacitances and volumetric sorption capacities are also correlated. The highest volumetric sorption capacity was found for garlic powder-derived activated carbon valuing 65.3 mol.m3 at a volumetric specific capacitance of 62.3 F.cm3 which is a two-fold increase compared to BPL 4x6 carbon which has a volumetric specific capacitance of 41.2 F/cm3 and a volumetric sorption capacity of 27.1 mol.m3. In addition, higher specific capacitance tends to improve the overall adsorption rate and productivity.


Porous carbons
Electrochemical CO2 capture
pH swing
CO2 adsorption
Carbon capture


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