Kinetics and mechanism of the transient behaviour of magnesium anodes

Abstract

The main objective of the present investigation is to study the mechanism of delayed dissolution of magnesium anodes during discharge of magnesium dry cells. A supplementary part of the work is devoted to the development of a new technique for the study of electrode kinetics at stationary solid electrodes under steady-state polarization. The use of primary batteries with magnesium anodes in place of zinc is likely to become increasingly popular both due to the superior electrical performance characteristics and the unlimited resources of magnesium as compared to that of zinc. One of the present limitations of the magnesium anode is its ‘delayed action’ during discharge. This effect manifests as a large, transient polarization during the initial periods of discharge. This spontaneous polarization decreases gradually with time of discharge until it reaches a relatively small, steady-state value at the operational current densities. Correspondingly, a magnesium primary cell shows a steep fall in terminal voltage at the beginning of discharge and the power output reaches an operational value only after a certain ‘delay-time’.