Corrosion and electrochemical behaviors of pure aluminum in novel KOH-ionic liquid-water solutions

摘要

The corrosion and electrochemical behaviors of pure aluminum in KOH-ionic liquid-water solutions with variable volume ratios of water and the ionic liquid 1-butyl-3-methyl imidazolium tetrafluoroborate (BMIMBF_4) were for the first time investigated by means of hydrogen collection, polarization curve, galvanostatic discharge, and electrochemical impedance spectroscopy (EIS).The results of hydrogen collection experiments showed that aluminum has a low corrosion rate in KOH-BMIMBF_4-H_2O solutions, and the corrosion rate decreases with increase in BMIMBF_4 content in the electrolytes. The results of electrochemical experiments revealed that aluminum is electrochemically active over a very wide potential window in the KOH-BMIMBF_4-H_2O solutions, and its electrochemically kinetic mechanism is similar to that in the corresponding aqueous solution; the increase in KOH and water contents in the electrolytes may improve the anodic dissolution performance of aluminum. It was found that aluminum presents excellent galvanostatic discharge performance in the 2.0 M KOH BMIMBF_4-H_2O mixed solution with 60% water.