Enhancement of the discharge performance of AP65 magnesium alloy anodes by hot extrusion

Discharge and Corrosion Performance of AP65 Magnesium Alloy in Simulated Seawater: Effect of Temperature

“…It is generally considered that the discharge performance of seawater-activated battery is mainly determined by the anode material, of which the alloying composition and microstructure feature exert a prominent effect on enhancing the cell voltage and inhibiting the parasitic corrosion reaction ( Ref 2,5). Thus, great effort has been made to obtain an improved anode performance, such as adding several alloying elements into magnesium, using heat treatment or plastic deformation to modify the microstructure of magnesium alloy ( Ref 1,2,5,6). All these methods refine the grains and make the alloying elements or secondary phases distribute homogeneously in the magnesium matrix; hence, accelerating the self-peeling of the discharge products (i.e., Mg(OH) 2 ) and inhibiting the side hydrogen evolution reaction occurring on the electrode surface (Ref 2, 6, 7).…”

“…Magnesium alloy is now becoming the anode material of choice for seawater-activated battery due to its combination of low density, high discharge activity, and large theoretical capacity (Ref [1][2][3]. This battery adopts seawater as the electrolyte, and the magnesium anode is activated in seawater to generate current via electrolytic dissolution (Ref 4).…”

Effects of microstructure evolution on discharge properties of AZ31 alloy as anode for seawater battery

“…Moreover, research conducted on magnesium alloys as anode materials for the seawater battery is attributed to its excellent discharge performance, that is, more negative electrode potential (i.e., −2.37 V [vs. saturated calomel electrode (SCE)]) and lower density (i.e., 1.74 g/cm 3 ) compared to aluminum and zinc, having a high theoretical specific capacity (i.e., 2.2 A•h/g) and, therefore, high specific energy density (i.e., 6.8 kW•h/kg). [4][5][6][7] Nevertheless, polarization caused by corrosion products adhering to the surface, severe self-corrosion, and low utilization performance of magnesium alloys remains to be solved. [8][9][10] Doping with alloying elements, such as Al, Li, Hg, Pb, Ga, Sn, In, Ce, and so on, is an effective way to improve the discharge performance of magnesium alloys.…”

“…[6,[10][11][12][13][14] Although Mg-Al-Pb and Mg-Hg-Ga alloys reveal excellent discharge activity and utilization efficiency, Pb, Hg, and Ga can be very harmful to the environment. [4,15,16] Mg-Li anodes can be a promising candidate for seawater battery anodes. [13,17,18] Nonetheless, there is a prominent safety issue in the melting process.…”

“…Plastic deformation and heat treatment, which can effectively modify microstructure, are also favorable to improve the discharge properties of magnesium anodes. [4,11,[21][22][23] Plastic deformation, usually hot extrusion and rolling, refines grains and, thus, can negatively shift the discharge potential to some extent. The fragmented second phase after plastic deformation is advantageous to the efficient discharge due to the decreased microgalvanic corrosion between matrix and second phase, whereas the influence of dispersed second phase on the discharge activity of Mg alloys is far from being conclusive.…”