Review—Electrochemical Surface Finishing and Energy Storage Technology with Room-Temperature Haloaluminate Ionic Liquids and Mixtures

In this article, we review the progress in the area of electrochemical technology with Lewis acidic haloaluminate room-temperature ionic liquids (RTILs), such as AlCl3–1-ethyl-3-methylimidazolium chloride and AlBr3–1-ethyl-3-methylimidazolium bromide, and novel chloroaluminate mixtures consisting of AlCl3 and polarizable molecules, e.g., dimethylsulfone and urea, during this decade. The number of researchers in the field seems to increase steadily, because now we can handle haloaluminate RTILs and their mixtures with other solvents and materials more easily than we could in the past. In this review, we have categorized the electrochemical technology based on these RTILs into two topics: electroplating and energy storage. In fact, much of the current research is based on work begun during the period from ∼1970 until the 1990's. But new findings and insights have been obtained through the application of state-of-the-art technologies. With this new information, haloaluminate RTILs and solvent mixtures have the spotlight again.