Study on electrolyte additives of water-based magnesium batteries

Abstract

The effects of different inorganic salt additives on the corrosion resistance, hysteretic behavior and activation potential of magnesium anode in MgSO4-Mg(NO3)2 composite electrolyte (1.86 mol·L-1 Mg(NO3)2 + 0.14 mol·L-1 MgSO4) were compared by electrochemical method. The electrochemical test results showed that in the solution containing 0.02 mol/L NaHCO3, the activation potential of magnesium anode was the most positive, the passivation range was expanded, and the polarization current was reduced. The impedance of magnesium alloy with 0.02 mol/L NaHCO3 has the highest corrosion resistance, which is consistent with the conclusion that the corrosion current density of Tafel polarization curve is the lowest. Under the additive concentration, the magnesium anode has the shortest lag time, the most negative discharge potential and the least potential drop, which greatly improve the discharge performance of magnesium anode.