Effect of sodium‐zinc EDTA and sodium gluconate as electrolyte additives on corrosion and discharge behavior of Mg as anode for air battery

• Published in: Materials and corrosion 2022-11, Vol.73 (11), p.1776-1787
• Main Authors: Qu, Jun‐e, Luo, Hongqin, Liu, Zhanxiang, Wang, Hairen, Chen, Yuwei, Yang, Lixia
• Format: Article
• Language: English
• Subjects: Additives; Air batteries; air battery; Corrosion; corrosion inhibitor; Discharge; discharge performance; Electrolytes; Ethylenediaminetetraacetic acids; Magnesium hydroxide; Metal hydroxides; pure magnesium; Sodium; Voltage drop
• ISSN: 0947-5117; 1521-4176
• DOI: 10.1002/maco.202213322

The corrosion inhibiting performance of EDTA‐ZnNa2 and C6H11NaO7 for pure magnesium in a 3.5 wt% NaCl electrolyte was investigated through electrochemical tests and surface microanalysis. And their effect on discharge behavior of Mg anode used for air battery was evaluated through constant‐current discharging tests. The inhibition performance varied with different additive concentrations and the maximum inhibition efficiency values were obtained as 87.11% and 77.70% by using 0.005 M EDTA‐ZnNa2 and 0.01 M C6H11NaO7, respectively. Both the presence of 0.005 M EDTA‐ZnNa2 and 0.01 M C6H11NaO7 in electrolyte improved the battery performance, especially under a smaller discharging current. The discharge platform time was extended from 15.66 to 22.57 h and 20.04 h by adding EDTA‐ZnNa2 and C6H11NaO7 at discharging current density of 2 mA cm−2 respectively, accompanied by a negligible battery voltage drop of about 20 mV. In the case of EDTA‐ZnNa2, zinc hydroxide formed by the dissociated zinc ions cooperated with magnesium hydroxide and organic adsorption film for corrosion inhibition. Therefore, by using it a more pronounced discharge performance was achieved than C6H11NaO7. Both the presence of EDTA‐ZnNa2 and C6H11NaO7 in a 3.5 wt% NaCl electrolyte improved the Mg air battery performance by inhibiting the self‐corrosion of Mg anode. In the case of EDTA‐ZnNa2, zinc hydroxide formed by the dissociated zinc ions cooperated with magnesium hydroxide and organic adsorption film for corrosion inhibition. Therefore, by using it a more pronounced discharge performance was achieved than C6H11NaO7.