Development of novel dilute Mg anode for primary Mg-air battery with great voltage and capacity synergy

This study investigates the microstructural characteristics and discharge performance of the as-rolled Mg-0.3Sn0.3Al-0.1Zn anodes with and without annealing. The results demonstrate that as-rolled anode exhibits a bimodal grain structure with local elements segregated regions. After annealing, the anode presents the bimodal sized grain structure without elements segregation. The Mg-air battery assumed by the as-annealed Mg-0.3Sn-0.3Al0.1Zn anode endows a high synergy between cell voltage and specific capacity at 10 mA cm-2 (1.4132 V and 1472.76 mA h g-1). The improvement in cell voltage can be mainly attributed to the more negative open-circuit potential, lower discharge resistance and more porous discharge product film. The enhanced specific capacity is ascribed to the lower surface voltage potential difference on the anode, suppression of the chunk effect and realtime hydrogen evolution rate.