Activating discharge and inhibiting self-corrosion by adding indium to the anode of Mg–air battery

Abstract

Self-corrosion and low practical voltage of anodes severely limit the usage of Mg–air batteries. Although many elements, including indium (In), have been used to enhance the discharge characteristics of Mg anodes, unclear mechanism of the action of a single element and lack of research on binary alloys as anodes have restricted the development of Mg–air batteries. Herein, Mg–xIn (x = 0.5, 1, 2, 4) alloys were melted as anode materials for Mg–air batteries. The In element in the Mg–In binary alloy activated the discharge process of the anode and inhibited self-corrosion and chunk effect, thereby greatly improving the voltage and anodic efficiency of the batteries. Mg–air batteries assembled from Mg–1In anode reached voltages exceeding 1.5 V at low current density and over 1.1 V even at 40.0 mA cm⁻². The Mg–1In anode exhibited a discharge efficiency greater than 63.2% at all current densities and demonstrated a peak specific energy of 2100.2 mW h g⁻¹. Furthermore, the Mg–1In anode performed well in long-term, intermittent, and constant-power discharges. The simple design of binary alloy and the activation and inhibition mechanisms of the In element provide a new avenue for Mg anode development.