(417b) Development of a Fully Automated Supercapacitive Swing Adsorption (SSA) Process for Carbon Capture

Supercapacitive swing adsorption (SSA)¹ is an electrochemical method of CO₂ capture that leverages the electrostatic attraction of CO₂ and carbonic acid to the electric double layer (EDL) formed within porous electrodes of a supercapacitor that is contacted with CO₂-containing gas. The formation of the EDL and subsequent adsorption of CO₂ follows the application of a potential difference across the supercapacitor. Desorption or release of adsorbed CO₂ is achieved by the restoration of the supercapacitor voltage to its pre-adsorption level (Figure 1). SSA promises some advantages over similar CO₂ capture technologies. Firstly, SSA does not require temperature and pressure changes, and thus avoids the energy costs incurred in the regeneration step of amine-based capture technologies. In addition, since CO₂ sorption is largely electrostatic, SSA offers shorter cycles and higher roundtrip efficiencies than redox-based methods.

The capture of CO₂ via SSA has been demonstrated in recent studies. These characterization studies provide insight into the effects of electrode material^2,3, electrolyte composition⁴, oxygen content in feed gas⁵ and charging parameters⁶ on adsorption capacity and efficiency. However, the continuous production of a high purity CO₂ stream via SSA for sequestration (or conversion into valuable chemicals) as in a commercial-scale plant, is yet to be addressed. To achieve this objective, we developed an automated SSA system (Figure 2) that extracts high purity CO₂ from a continuous gas feed. Automated coordination between charge/discharge protocols of the dual module system and gas flow sequence is achieved with a programmable microcontroller. We present experimental results using this design with gas feed concentrations ranging from 15% to 400 part per million CO₂. Valuable insight gleaned from our architecture will accelerate the development of pilot-scale and ultimately, commercial point source and direct air capture applications.

References

1. Kokoszka, B., Jarrah, N.K., Liu, C., Moore, D.T., Landskron, K.: Supercapacitive swing adsorption of carbon dioxide. Angewandte Chemie International Edition 53(14), 3698–3701 (2014).
2. Bilal, M., Li, J., Landskron, K.: Enhancing supercapacitive swing adsorption of CO₂ with advanced activated carbon electrodes. Advanced Sustainable Systems 7(11), 2300250 (2023)
3. Xu, Z., Mapstone, G., Coady, Z., Wang, M., Spreng, T.L., Liu, X., Molino, D.,Forse, A.C. Enhancing electrochemical carbon dioxide capture with supercapacitors. Nature Communications 15(1), 7851 (2024)
4. Zhu, S., Li, J., Toth, A., Landskron, K.: Relationships between the elemental composition of electrolytes and the supercapacitive swing adsorption of CO₂. ACS Applied Energy Materials 2(10), 7449–7456 (2019)
5. Bilal, M., Li, J., Kumar, N., Mosevitzky, B., Wachs, I.E., Landskron, K.: Oxygen-assisted supercapacitive swing adsorption of carbon dioxide. Angewandte Chemie 136(39), 202404881 (2024)
6. Binford, T.B., Mapstone, G., Temprano, I., Forse, A.C.: Enhancing the capacity of supercapacitive swing adsorption CO₂ capture by tuning charging protocols. Nanoscale 14(22), 7980–7984 (2022)