As discussed above, at thermodynamic equilibrium we would anticipate no difference in the CO2 capture behaviour under positive and negative charging modes. Our proposed mechanism above also suggests that at thermodynamic equilibrium, less or potentially even zero CO2 may be captured. Indeed, at long time scales, the CO2 gas would have enough time to diffuse through the whole supercapacitor system and create a pseudo-symmetric system where neither of the electrodes is more gas exposed than the other. This would create the conditions for the capture and release of CO2 at the same time. To test this hypothesis, SSA experiments were carried out with much longer voltage holds with a duration of 6-hours. Here, a voltage window of -0.4 to 0 V was used to reduce the impact of corrosion to the stainless-steel coin cell components, which is exaggerated when using longer voltage holds (SI Figure ). Figure , shows that holding the cell voltage for longer results in no apparent net capture of CO2. Initially, as the supercapacitor is charged in a negative direction, there is the expected pressure drop indicating the capture of CO2. Then within an hour, this captured CO2 begins to desorb and the pressure returns to an apparent equilibrium position. A similar phenomenon then occurs when charging in a positive direction back to 0 V (Figure ). Initially, there is the release of CO2 and then at longer times the CO2 is captured again with the pressure returning to the same apparent equilibrium position. These findings contrast significantly with the much faster SSA experiments in Figure , and show that it is the direction of current flow that determines whether CO2 is captured or released. The same trends are seen for both the positive and switching charging protocols (SI Figure ) with the experiment repeated a total of three times to ensure a reproducible result (SI Figure ).