4. Electrolytes

If, thanks to an anodic oxidation at one electrode and a cathodic reduction at the other, the current can cross the two terminal interfaces of an electrolyte (or a chain of electrolytes), another phenomenon is involved in its passage through the electrolytic medium: the migration of ions (electric charge carriers) under the effect of the electric field:

in the medium. The opposite signs of their charge mean that the two types of ions, anions and cations, migrate in opposite directions: anions (which circulate in the same direction as the electrons in the electrodes and external circuit) migrate towards the anode, and cations towards the cathode (hence their names).

The overall result of this ionic migration is to maintain electroneutrality...