Impacts of supercapacitor electrode structure on electrochemical CO2 capture

Anthropogenic CO2 emissions cause global warming, driving the need for decarbonisation technologies. Supercapacitors, originally designed for energy storage, are emerging as energy-efficient and robust devices for electrochemical CO2 capture. However, impacts of electrode structure and charging protocols on CO2 capture performance remain unclear. This study develops structure-performance relationships for supercapacitor electrodes at different charging conditions. In general, we find that electrodes with large surface areas and low oxygen functionalisation perform the best, while a combination of micro- and meso-pores is essential to achieve fast capture rates. By combining these structural features, the YP80F activated carbon electrode shows the best CO2 capture performance (350 mmolCO2 kg–1 h–1 and 18 kJ molCO2–1, under 300 A kg–1, 0.8 V and pure CO2), a long lifetime over 12000 cycles, and promising CO2 selectivity over O2 and N2. This study paves the way to develop supercapacitor electrodes for electrochemical CO2 capture.