The effect of different concentrations of Na₂SnO₃ on the electrochemical behaviors of the Mg-8Li electrode

Abstract

In this research, the effect of the different concentrations of NaSnO₃ as the electrolyte additive in 0.7 mol L⁻¹ NaCl solution on the electrochemical performances of the magnesium-8lithium (Mg-8Li) electrode are investigated by methods of potentiodynamic polarization, potentiostatic current-time, electrochemical impedance technique, and scanning electron microscopy (SEM). The corrosion resistance of the Mg-8Li electrode is improved when Na₂SnO₃ is added into the electrolyte solution. The potentiostatic current-time curves show that the electrochemical behaviors of the Mg-8Li electrode in the electrolyte solution containing 0.20 mmol L⁻¹ Na₂SnO₃ is the best. The electrochemical impedance spectroscopy results indicate that the polarization resistance of the Mg-8Li electrode decreases in the following order with the concentrations of Na₂SnO₃: 0.05 mmol L⁻¹ > 0.00 mmol L⁻¹ > 0.30 mmol L⁻¹ > 0.10 mmol L⁻¹ > 0.20 mmol L⁻¹. The scanning electron microscopy studies indicate that the electrolyte additive prevents the formation of the dense oxide film on the alloy surface and facilitates the peeling off of the oxidation products.