Discharge properties of Mg-Sn-Y alloys as anodes for Mg-air batteries

Mg-Sn-Y alloys with different Sn contents (wt%) were assessed as anode candidates for Mg-air batteries. The relationship between microstructure (including the second phase, grain size, and texture) and discharge properties of the Mg-Sn-Y alloys was examined using microstructure observation, electrochemical measurements, and galvanostatic discharge tests. The Mg-0.7Sn-1.4Y alloy had a high steady discharge voltage of 1.5225 V and a high anodic efficiency of 46.6% at 2.5 mA center dot cm(-2). These good properties were related to its microstructure: small grain size of 3.8 mu m, uniform distribution of small second phase particles of 0.6 mu m, and a high content (vol%) of (11 (2) over bar0)/(10 (1) over bar0) orientated grains. The scanning Kelvin probe force microscopy (SKPFM) indicated that the Sn3Y5 and MgSnY phases were effective cathodes causing micro-galvanic corrosion which promoted the dissolution of Mg matrix during the discharge process.

Automated summary

The microstructure of Mg-Sn-Y alloys, including small grain size, uniform distribution of small second phase particles, and specific grain orientation, plays a crucial role in determining their discharge properties in Mg-air batteries. The presence of effective cathodes like Sn3Y5 and MgSnY phases promotes micro-galvanic corrosion, leading to the dissolution of the Mg matrix during discharge process.