By convention, such half-reactions are always written as reduction (electron addition) processes, a formalism which is important in the quantitative treatment of redox reactions and equilibria (to be presented in section 4.2).

An electric potential difference is created between the electrodes that causes a charge and the appropriate counter ion from the electrolyte to enter the polymer in the form of electron addition (i.e., n-doping) or removal (i.e., p-doping).