Investigation of the influence of voltage pulse on the initial delayed action of Mg batteries

Abstract The paper discusses the influence of voltage pulse on the delayed action of AZ31B magnesium (Mg) alloy in MgSO4–Mg(NO3)2 composite solution by using galvanostatic discharge and electrochemical impedance spectroscopy for the first time. The peak potential of Mg anode applied with pulse signal is only −1.25 V, which reduces by ~2 V compared to the Mg electrode without pulse (+0.8 V). The potential dip of Mg anodes without and with pulse load are ~1.88 V and ~0.06 V, respectively. Furthermore, the superior discharge behaviors of Mg electrode can be maintained despite that immersion time length is extended to 10 days at the pulse signal of −1.0 V - 100 ms. Finally, the surface morphology and composition of Mg alloys are analyzed by scanning electron microscopy and X-ray photoelectron spectroscopy. The results show that voltage pulse has a slightly impact on the composition of surface products, whereas, it improves the electrochemical properties of Mg electrode in aqueous solution by destroy the outer layer while does not affect the inner film.