Electrochemical behavior of aluminum in Grignard reagents/THF electrolytic solutions for rechargeable magnesium batteries

The electrochemical behavior of the aluminum current collector with a fresh surface (the scratched aluminum foil) in three kinds of Grignard reagents/THF electrolytic solutions has been studied by cyclic voltammetry (CV), X-ray photoelectron spectroscopy (XPS) analysis methods. The experimental results show that the passivating film on aluminum foils after five cycles of CV tests is mainly composed of Al2O3. The pitting potentials of scratched aluminum foils in three kinds of Grignard reagents/THF electrolytic solutions increase in the order of EtMgCl/THF < EtMgBr/THF < PhMgCl/THF, which indicates that the selection of electrolytic solutions species is important for the aluminum current collector to suppress the pitting corrosion. The corrosion behavior of three kinds of aluminum foils used as the current collector by different surface treatment processes, which include removal of the oxide film (the scratched aluminum foil), exposing at room temperature (the normal aluminum foil) and high temperature oxidation (the heated aluminum foil), in 1 mol L-1 EtMgBr/THF solution has been investigated by electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR) analysis methods. The pitting resistance of aluminum foils by different surface treatment processes in 1 mol L-1 EtMgBr/THF solution increases in the order of the scratched aluminum foil < the heated aluminum foil < the normal aluminum foil. These results demonstrate that a layer of dense protective oxide film is important for the aluminum current collector to suppress the pitting corrosion. (C) 2012 Elsevier Ltd. All rights reserved.