A novel Ti–6Al–4V particle-regulated Mg–9Al–1Zn Mg–air battery anode with high discharge stability

Abstract

In this work, the effect of adding micron Ti–6Al–4V (TC4; the mass percentages of TC4 particles added were 0, 5, 10, 20 wt%) particles on the electrochemical properties of spark plasma-sintered Mg–9Al–1Zn (AZ91) composites as an anode of Mg–air batteries was investigated. Microscopic characteristics revealed that all fabricated samples with different TC4 particle contents had similar grain sizes, low-density dislocations, weak crystal orientation and nanoscale Mg₁₇Al₁₂ particles. These fine Mg₁₇Al₁₂ particles and micron TC4 particles with a higher potential than that of the α-Mg matrix contributed to the enhancement of the anodic dissolution kinetics, resulting in a higher discharge voltage. Consequently, the TC4 particle-modified AZ91 anode for Mg–air batteries exhibited good discharge voltage stability and maintained a higher cell voltage during long-term discharge compared to the AZ91 anode, especially under high current density discharge conditions. This phenomenon was mainly attributed to the uniform dissolution of the anode caused by the grain boundary and Mg₁₇Al₁₂ phases as well as the detachment of the discharge products caused by the TC4 particles, making the AZ91-TC4 composite a suitable anode material for primary Mg–air batteries.