This picture is modified slightly near charged electrode interfaces. When CO 3 2is near the cathode, the negatively charged electrode attracts Na + cations bringing them closer to the anion, further penalizing ion dissociation. Near an anode, the opposite occurs, with the positively charged electrode repelling Na + away from CO 3 2 -, slightly mitigating the excluded volume effect. This destabilization does not explain the increase in auxiliary ion effect. Near a neutral electrode, the free energy cost of moving Na + from the contact to solvent-separated minimum increases from 5.25 k B T to 6.5 k B T and finally 7k B T when the auxiliary cation is in the contact, solvent-separated and dissociated state respectively. The net auxiliary ion effect of 1.75 k B T is nearly double what is seen in bulk water and can not be explained by direct Coulomb repulsion between cations. This discrepancy suggests that the cations become more correlated near the interface due to a change in solvation near the interface.