A Scientific Study of Current Collectors for Mg Batteries in Mg(AlCl₂EtBu)₂/THF Electrolyte

The electrochemical behavior and stability of several current collectors (copper, nickel, stainless steel 316L, aluminum, titanium) potentially employed in magnesium batteries with non-aqueous Mg(AlCl 2 EtBu) 2 /THF electrolyte have been investigated in both three-electrode electrochemical cell and coin cell configurations. Linear sweep voltammetry and coin cell charge/discharge measurements indicate that copper, widely used in the literature as a current collector in this electrolyte, is not stable and undergoes pitting corrosion above ∼1.8 V. Cyclic voltammetry shows that copper undergoes electrochemical oxidation and reduction in the electrolyte, which was further confirmed by inductively coupled plasma atomic emission spectroscopy (ICP-AES), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) analyses. Among the current collectors studied, nickel shows excellent electrochemical stability up to ∼2.2 V and high efficiency for magnesium deposition and dissolution processes in the electrolyte, indicating that it is a strong candidate as both cathode and anode current collectors in magnesium batteries.