Insights into Corrosion of Current Collectors for Magnesium Batteries

Abstract

To enable the shift towards renewable energy, the use of low-cost energy storage systems is necessary. Magnesium (Mg) is an abundant and safer raw material than lithium for electrochemical energy storage systems such as batteries, due to its reduced sensitivity to air. Promising intercalation materials for cathodes include Chevrel phase Mo6S8 and Prussian green FeFe(CN)6. Although magnesium perchlorate-based electrolytes are practical for early-stage cathode research, they are not compatible with Mg metal due to corrosion. The organo-metallic all phenyl complex (APC) based electrolyte is a potential candidate for magnesium full cells, but both systems contain reactive chloride species that cause severe corrosion of the current collector. This study utilizes linear sweep voltammetry, chronoamperometry, and electrochemical impedance spectroscopy to identify suitable materials for current collectors, including carbon-coated Al and Ni. The selected materials must withstand a polarization potential of 2 V vs. Mg/Mg2+. A Graphite-based current collector is shown to be the most promising candidate due to its low areal density, which can increase the energy density of practical Mg batteries.