UC Berkeley

We derive a general relationship between the applied potential across a binary electrolyte in a symmetric cell and steady-state current density, iss. The relationship is applicable to salts comprising ions that are either univalent or multivalent. In concentrated solutions, iss depends on the electrolyte conductivity which governs i0, the initially recorded current density at time zero when the potential is applied, and a dimensionless parameter derived here in terms of multicomponent transport coefficients. In the dilute limit, the ratio iSS/i0 is the cation transference number, irrespective of the charge on the cation or the anion.