Transient currents of electrolytes in response to a voltage step can reveal a lot about the behavior of charges present in an electrolyte. In this paper, electrolytes with high ionic strength are considered. In the limit of small voltage steps, the interpretation is straightforward as the equations describing the transient can be linearized. However, when high ion concentrations and voltage steps of the order of $kT∕q$ are considered, we find higher-order effects that occur simultaneously with the diffuse double layer charging. In this case, the diffuse double layer and the transient diffusion layer are coupled because of the screening of the field, leading to a $-3∕2$ power law for the transient current.

• Received 23 September 2008

DOI:https://doi.org/10.1103/PhysRevE.79.011502