Evaluation of corrosion inhibition role of conventional surfactants for zinc in alkaline battery solution

One of the most important changes in the characteristics of the MnO2-Zn dry cell as known before the 1960s occurred when caustic electrolytes were introduced to the technology of thissystem on a large scale. The current-carrying capability, capacity, and shelf life increased considerably, and today this type of galvanic cell has a wide range of application. Despite the mentioned advantages, these type of batteries suffer from a serious drawback of corrosion inalkaline medium which often results in a leakage. To overcome this problem, the employment of environmentally friendly surfactants, as corrosion inhibitors is gaining large preference and interest due to its safe effect, practical use and low cost. Most of the surfactants used as corrosioninhibitors are organic molecules having a notable inhibition efficiency in their CMC values. The corrosion inhibition mechanism of surfactants at the metal surface includes the adsorption ofthese species on the metal surface. Electrochemical characterization of the studied system wasdone in an three electrode array including Ag/AgCl (satd), Zink specimen, and Pt as reference, working, and counter electrodes, respectively, in The aggressive solution 7.0 M KOH prepared using 99% KOH. Corrosion inhibition efficiency of Dotab surfactant on zinc in 7.0 M KOHsolution was evaluated by polarization as EIS techniques. Results evidenced that Dotab surfactant can improve the corrosion inhibition of zinc and enhance the capacity of battery. The inhibitionefficiency enhances with increasing the surfactant concentration. The maximum inhibition efficiency is above 90% at CMC (0.4 mM). Polarization curves proved that Dotab surfactant is an efficient corrosion inhibitor.

Keywords:

Alkaline batteries , Corrosion inhibition , Discharge capacity , Polarization , Surfactant