Abstract
Supercapacitors are emerging as energy-efficient and robust devices for electrochemical CO(2) capture. However, the impacts of electrode structure and charging protocols on CO(2) capture performance remain unclear. Therefore, this study develops structure-property-performance correlations for supercapacitor electrodes at different charging conditions. We find that electrodes with large surface areas and low oxygen functionalization generally perform best, while a combination of micro- and mesopores is important to achieve fast CO(2) capture rates. With these structural features and tunable charging protocols, YP80F activated carbon electrodes show the best CO(2) capture performance with a capture rate of 350 mmol(CO2) kg(-1) h(-1) and a low electrical energy consumption of 18 kJ mol(CO2)(-1) at 300 mA g(-1) under CO(2), together with a long lifetime over 12000 cycles at 150 mA g(-1) under CO(2) and excellent CO(2) selectivity over N(2) and O(2). Operated in a "positive charging mode", the system achieves excellent electrochemical reversibility with Coulombic efficiencies over 99.8% in the presence of approximately 15% O(2,) alongside stable cycling performance over 1000 cycles. This study paves the way for improved supercapacitor electrodes and charging protocols for electrochemical CO(2) capture.