Corrosion Study of Current Collectors for Magnesium Batteries

Abstract For rechargeable magnesium batteries, chlorine‐containing electrolytes are used because chlorine species reduce the energy barrier for the intercalation process at the cathode. However, these species can cause corrosion of the cathode‐side current collectors during polarization. In this study, carbon‐coated aluminum and Nickel metal substrates, as well as a graphite foil, were investigated using Linear Sweep Voltammetry, Chronoamperometry, and Electrochemical Impedance Spectroscopy to evaluate their potential as current collectors in APC electrolyte. The graphite‐based current collector withstood corrosive environments at polarization potentials up to 2 V, displaying passivating behavior comparable to platinum in Chronoamperometry measurements. During Electrochemical Impedance Spectroscopy measurements, the graphite foil exhibited exceptionally high polarization resistance of at least 4.5 MΩ cm². Combined with its low areal density of 5 mg/cm⁻², this makes it an excellent current collector material for rechargeable magnesium batteries with chlorine‐containing electrolytes. In contrast, Al foil are instable towards corrosion – despite protective coatings.