Impact of Surface Microstructure and Properties of Aluminum Electrodes on the Plating/Stripping Behavior of Aluminum-Based Batteries Using Imidazolium-Based Electrolyte.

Abstract

The 99.99% Al used for negative Al electrodes in aluminum-based battery studies is expensive. This is primarily due to the complex challenges associated with fabricating 99.99% Al, particularly the removal of Fe impurities from Al melts. Despite the importance of this issue for the future commercialization of Al-based batteries, it has been largely overlooked. This work accordingly studied the plating/stripping behavior of Al containing 1 wt % iron (Al 1% Fe) as an alternative electrode using conventional ([EMIm]Cl and AlCl3) electrolyte. Simultaneously, the impact of the surface microstructure of Al 1% Fe on the plating/stripping behavior was examined. The results indicate that the difference in the plating/stripping cycling of Al 1% Fe alloys and 99.99% Al is negligible. Thus, Al 1% Fe negative electrodes could serve as an efficient and commercially viable alternative to 99.99% Al for plating/stripping in Al-based batteries. This is an essential finding because facile and commercial fabrication of Al 1% Fe electrodes is absolutely feasible. The results are further discussed in terms of the impact of the Al surface microstructure (i.e., grain size, defect density, grain boundary distribution, crystal orientation, and intermetallic phases) on plating/stripping behavior. Moreover, this study provides insights into how the interphase layer formed on Al electrodes influences plating/stripping behavior.