The Influence of Electroless Silver Deposition on Electrochemical Properties of the Steel Cathode Current Collector of Alkaline Batteries

摘要

The influence of electroless silver layer on the electrochemical behavior of steel cathode currentcollector was examined in rechargeable alkaline MnO2-Zn batteries. For that purpose, batteries weredismantled after various stages of charge/discharge cycles, followed by polarization measurements andmorphological analysis of their steel collectors. The current collectors of spent batteries were used forconstruction of a new series of batteries. Results indicate that the formation of passive surface film onthe steel current collector impairs the charge/discharge cycle performance of batteries. To overcomethe difficulties, electroless silver coating on steel collector was proposed. SEM analysis has shownthat, the surface defects density and accumulation of corrosion products on steel collector is higherthan that of Ag coated collector. Furthermore, the second cycle discharge capacity and the rate ofcapacity fading of batteries with silver coated collectors were lower in comparison with batteries basedon steel collector. Results of electrochemical impedance spectroscopy (EIS) have confirmed that thepolarization resistance of steel current collectors is higher than that of the corresponding silver coatedcollectors.