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

Abstract The corrosion inhibiting performance of EDTA‐ZnNa 2 and C 6 H 11 NaO 7 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‐ZnNa 2 and 0.01 M C 6 H 11 NaO 7 , respectively. Both the presence of 0.005 M EDTA‐ZnNa 2 and 0.01 M C 6 H 11 NaO 7 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‐ZnNa 2 and C 6 H 11 NaO 7 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‐ZnNa 2 , 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 C 6 H 11 NaO 7 .