Abstract At the beginning of the reaction in the primary battery of "Mg|NaOH(aq)|Al", magnesium was the negative electrode, then aluminum turned into negative electrode after a few seconds. Based on the formation theory of primary battery and the analysis of the reaction of saturated sodium carbonate solution with magnesium and aluminum respectively by thermodynamic and dynamics, this paper explained the theoretical basis for the reversal of the primary battery electrode properties, and presented that there was no substantive difference between primary battery reaction and oxidation-reduction reaction at the micro level.
