Electrochemical behavior of Mg electrode in sodium salt electrolyte system

Yu Zhang; Qingguang Zhu; Chang Su; Chao Li

doi:10.3389/fchem.2022.992400

Electrochemical behavior of Mg electrode in sodium salt electrolyte system

Front Chem. 2022 Sep 9:10:992400. doi: 10.3389/fchem.2022.992400. eCollection 2022.

Authors

Yu Zhang^{1

2}, Qingguang Zhu¹, Chang Su¹, Chao Li^{1

2}

Affiliations

¹ College of Chemistry and Chemical Engineering, Xinyang Normal University, Xinyang, China.
² Xinyang Key Laboratory of Low-Carbon Energy Materials, Xinyang Normal University, Xinyang, China.

Abstract

A suitable electrolyte is crucial to enhancing the electrochemical performance of magnesium (Mg) batteries. Here, the influence of Na₂SiO₃ on the electrochemical behavior of AZ31B Mg alloy in the Na₂SO₄-NaNO₃ composite electrolyte was investigated. The results revealed that the activation potential of the AZ31B Mg alloy first represented a negative shift and then a positive shift with the increase in Na₂SiO₃. The most negative activation potential (-1.51 V) and the lowest polarization (-3.20 V) were found when 6 mM of Na₂SiO₃ was added; no discharge hysteresis was observed, and the polarization resistance value (R ₁) was 3,806 Ω. After 24 h immersion in the composite electrolyte with Na₂SiO₃, more and wider cracks appeared on the alloy surface, where a thick, dense film was formed, showing excellent discharge performance and corrosion resistance.

Keywords: AZ31B Mg alloy; Na2SiO3; composite electrolyte; corrosion behavior; electrochemical performance.