Tracing the influence of small additions of antimony to zinc on the hydrogen evolution and anodic dissolution processes of zinc as anodes for alkaline batteries application

The processes of hydrogen evolution reaction and anodic dissolution of zinc and zinc antimony alloys with different antimony amounts (0.5 and 1%) immersed in 6 M KOH were tested via many electrochemical methods as Tafel polarization, cyclic voltammetry (CV), impedance spectroscopy (EIS), and charge-discharge. Newly formed phases, the morphology of the surface, and chemical composition for Zn and Zn-Sb alloys after and before corrosion were determined via appreciated analysis instruments as X-ray diffraction (XRD), scanning electron microscopy (SEM) provided with an energy-dispersive X-ray spectroscopy detector (EDS). The results of Tafel plots exhibited that, the protection efficiency of corrosion (h%) gets greater with the increase of both temperature and Sb content. It is impressive to note that, h% for Zn-Sb alloy (1%Sb) reaches the highest value of 98.55% at the higher studied temperature (55 degrees C). The potential of corrosion (Ecorr.) is shifted to a more negative position with the increase of antimony addition to zinc. This reveals that minor alloying amounts of Sb with Zn plays an important role to improve the suppression of the evolved hydrogen, charge efficiency, capacitance, and lifetime of alkaline batteries. Surface investigations revealed the presence of ZnSb and Zn4Sb3 phases on the alloy surface have an essential function in the protection of zinc anodes, and improvement of charge-discharge. (c) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.