Basic studies on electromechanical power sources

Abstract

The extended shelf life of high-energy primary batteries based on lithium, magnesium, and aluminum is primarily attributed to the presence of a protective passive film on the surface of the reactive metal anode. Evaluating the physical and electrochemical properties of this film-covered anode/solution interface is therefore of significant practical importance in such battery systems. In the present study, a non-destructive electrochemical technique has been developed to achieve this evaluation. The method relies on analyzing cell voltage transients and alternating current (AC) impedance in the absence of any film breakdown. Several plausible equivalent circuit models have been theoretically investigated to identify the one that most accurately represents the physical conditions at the film-covered anode/solution interface. This analysis enables the determination of equivalent circuit parameters governing the physicochemical processes occurring within these cells. The proposed method has been successfully demonstrated using the Mg–MnO? dry cell, a typical representative of high-energy primary batteries with film-covered anodes, and can be extended to other battery systems employing lithium, magnesium, or aluminum. The technique overcomes several limitations of earlier approaches reported in the literature and is readily adaptable for quality control, design optimization, and shelf-life studies of such batteries.