Stability of Current Collectors Against Corrosion in APC Electrolyte for Rechargeable Mg Battery

Rechargeable magnesium batteries (RMBs) are highly attractive due to their high volumetric capacity, relatively low cost, and enhanced safety. Significant progress in the development of RMBs was the introduction of nonaqueous electrolyte solutions that enable reversible electrodeposition of Mg metal. These solutions contain a unique mixture of organo−aluminum and chloro−aluminum species. While these solutions are shown to be stable during cathodic polarization, the presence of chlorine anions in the solution can promote the corrosion process during the anodic polarization. Among all the cell components, the cathode current collector is most prone to corrosive processes. In this study, we characterize the corrosion behavior of different metallic current collectors in standard APC (All-Phenyl Complex) electrolyte solutions by following their electrochemical response and surface morphology changes during anodic polarization. In addition, we investigate the influence of carbon coating on the corrosive behavior of Ni metal. The study shows the efficacy of carbon coating on the current collector. We demonstrate that Ni@C current collector possesses higher corrosion pit initiation potential (2.25 V vs Mg/Mg2+) with respect to the uncoated metallic foils. Improving the anodic stability of the current collectors is a crucial step in the development of a practical rechargeable Mg battery.