A NOVEL ELECTROCHEMICAL METHOD FOR MEASURING SALT DIFFUSION-COEFFICIENTS AND ION TRANSFERENCE NUMBERS

We have found it possible to determine salt diffusion coefficients and ion transference numbers by obtaining, respectively, the steady state ion-transport-limited current at a microdisk electrode in spherical d iffusion geometry and the transient ion-transport-limited current at a macrodisk electrode in planar diffusion geometry in ionic solutions c ontaining no supporting electrolyte. The method is demonstrated in aqu eous solutions of AgNO3 and in propylene carbonate solutions of LiClO4 . The ion transport parameters obtained agree well with those reported previously. It would appear that the method also could be used in the study of ion transport in solid electrolytes.