The Effects of NaHCO3on the Voltage Delay of Mg Cell with AZ31B Magnesium Alloy in Mg(ClO4)2Electrolytic Solution

The delayed action effect is a main obstacle for Mg/MnO2 battery to deliver instantaneous power on discharge from an open-circuit condition. A new low-cost inorganic electrolyte consisting of 2 M Mg(ClO4)2 and 0.04 M NaHCO3 was proposed and reduced the delayed parameters of the anode to a negligible degree even after aging of 16 d. The results from electrochemical impedance spectroscopy indicated that the addition of 0.04 M NaHCO3 significantly enhanced the corrosion resistance of AZ31B magnesium alloy. Anodic utilization efficiency of AZ31B was also increased by 10% compared with the commonly-used Mg(ClO4)2 at a small current density of 2.5 mA cm−2. The analysis of FT-IR and XPS results revealed that the composition of the corrosion product film formed in this new electrolyte was a mixture of MgO, Mg(OH)2, Mg5(CO3)4(OH)2·4H2O and Mg(ClO4)2.