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, the unclear mechanism of the action of a single element as well as the lack of research on binary alloys as anodes have restricted the development of Mg-air battery. Here, Mg-xIn (x = 0.5, 1, 2,4) alloys are melted as anode materials for Mg-air batteries. The In element in the Mg-In binary alloy activates the discharge process of the anode and inhibits self-corrosion and chunk effect, thereby greatly improving the voltage and anodic efficiency of the batteries. Mg-air batteries assembled from Mg-1In anode reach 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 exhibits a discharge efficiency greater than 63.2% at all current densities, and it demonstrates a peak specific energy of 2100.2 mWh 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.