Electrodeposition of Aluminum in Ionic Liquids

Compared with the industrial Siemens-Galvano-Aluminum (SIGAL) process, electrodeposition of aluminum (Al) in ionic liquids (ILs) has gained more and more attention due to the excellent characteristics of ILs, such as almost non-volatile, wider electrochemical window, higher conductivity, and so on. Therefore, in this article we give a detailed report on the development of this field. In order to enhance the potential of ILs used as electrolytes for Al electrodeposition, this article also reviews the background and historical development of electrodeposition of Al in ILs. Through summarizing, we find that the chloroaluminate ILs with imidazolium as the cations are still the most prospective electrolytes for large-scale application, and moisture sensitivity is the biggest obstacle restricting its development. Therefore, researchers have been looking for stronger water resistant ILs, but the water insensitive ILs are hard to combine with low viscosity and high electrochemical conductivity, leading to little research work done for the industrial application of electrodeposition of Al in ILs. In addition, the existing problems in basic research and application of electrodeposition of Al in ILs are summarized.