Influences of L-Cysteine/Zinc Oxide Additive on the Electrochemical Behavior of Pure Aluminum in Alkaline Solution

Abstract

Severe self-corrosion is the main barrier preventing the application of aluminum as an anode material in alkaline air battery. In this work, a hybrid organic/inorganic inhibitor based on L-Cysteine/zinc oxide was tested to see if its addition to alkaline electrolyte can reduce self-corrosion of a commercial 1060 pure aluminum. Results obtained have shown that self-corrosion of pure aluminum is significantly restrained by the L-Cysteine/ZnO hybrid inhibitor without affecting its discharge performance. An interaction between ZnO and L-Cysteine leads to formation of a dense layer on pure aluminum surface. In both NaOH + ZnO and NaOH + L-Cysteine + ZnO solutions, the reaction mechanism is mainly controlled by diffusion of zincate ions. By using the L-Cysteine/ZnO hybrid inhibitor, cheap commercial 1060 pure aluminum can replace expensive 5N5 super-pure aluminum to achieve a comparable performance. This has been demonstrated in this study by comparing the battery based on commercial 1060 pure aluminum with the L-Cysteine/ZnO inhibitor and the battery made of 5N5 super-pure aluminum with 4 M NaOH solution.