To understand the trade-off between thermodynamic and kinetic effects, a series of SSA experiments and simulations were carried out in which the current density was varied in the negative charging mode (Figure , 3c) and the trends in the pressure curves were examined closely (Figure , 3e, 3f). The experimental measurements revealed a maximum CO2 adsorption capacity of 57 ± 4 mmol kg -1 at 30 mA g -1 (Figure ). At this current density, the variation of the CO2 pressure is synchronous with the device voltage (Figure ). However, if the supercapacitor is charged more slowly, with current densities below 30 mA g -1 , then a reduction in the adsorption capacity occurs (Figure ). The same trends were reported by Xu et al. when YP80 activated carbon was used as the electrode material and by Zhu et al. when BPL 4x6 carbon was used. This indicates that this behaviour is consistent across different activated carbon electrodes.