The quasicrystal of Mg–Zn–Y on discharge and electrochemical behaviors as the anode for Mg-air battery

Abstract

In this work, the effect of quasicrystal I phase (Mg3Zn6Y) on electrochemical behaviors and discharge properties of as-cast Mg–Zn–Y alloys with different Zn/Y ratio for Mg-air batteries are systematically investigated in 3.5 wt % NaCl electrolyte. The Mg–6%Zn–1%Y (wt.%) alloy is composed of Mg matrix and I phase, while the Mg7Zn3 phase appears in Mg–10%Zn–1%Y alloy. The Mg–Zn–Y anodes have higher open circuit potential, electrochemical activity and corrosion resistance than the contrasted ZK60 anode. They also have higher cell voltage, specific capacity and anodic efficiency with more stable discharge curves. The I phase is responsible for such improvements. The Mg–6%Zn–1%Y alloy achieves its best discharge capacity and anodic efficiency at the 40 mA cm−2, with the values of 1162.79 mAh·g−1 and 55.14%, respectively, which are 22.38% and 23.14% higher than ZK60 anode. Shallow pits with smooth surfaces are observed in Mg–Zn–Y anodes after discharge process. Some small holes associated with the desorption ability are detected as well.