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), Mg-5(CO3)(4)(OH)(2) center dot 4H(2)O and Mg(ClO4)(2). (C) 2017 The Electrochemical Society. All rights reserved.