Tailoring corrosion and discharge performance of Mg anode by corrosion inhibitor

Abstract

The effect of various amounts of 5-sulfosalicylic acid (SSA) on the corrosion and discharge property of pure magnesium (Mg) is studied systematically. It was found that SSA plays a vital role in regulating the dissolution kinetics of the substrate and re-deposition rate of discharge product at the metal/electrolyte interface. Low concentration of SSA can be used as corrosion inhibitor for active Mg surface as it chelates with impurity element (Fe3+), while high concentration of SSA increases dissolution rate of Mg since large amount of SSA also acts as complexing agent for the dissolved Mg2+. In terms of discharge performance, addition of 0.1 M SSA improves the utilization efficiency and lowers the discharge potential in the meanwhile under different current densities. The anode demonstrates low and stable discharge potential (-1.83 V) for 10 h at 2.5 mA cm−2 in SSA containing electrolyte. Localized corrosion of the substrate has been significantly facilitated during discharge test. “Thorn-like effect” has been observed for the first time for Mg with addition of complexing agent.