Electrochemical behaviors and discharge performance of Mg-Sn binary alloys as anodes for Mg-air batteries

Abstract

In this work, the self-corrosion and discharge performance of the as-cast Mg-xSn (x=1, 5, 9 wt.%) anodes for primary Mg-air batteries were studied through microstructure characterization, electrochemical testing and discharge experiments. With the increase of Sn content, the volume fraction of the Mg2Sn phase increases, promoting dendrite refining. According to the electrochemical test, the Mg-1Sn anode shows a higher open circuit potential, resulting in a stronger electrochemical activity. The polarization curve and electrochemical impedance spectra show the corrosion resistance order as Mg-1Sn>Mg-5Sn>Mg-9Sn. In the discharge measurement, the Mg-1Sn anode achieves the best average discharge voltage, anode efficiency, specific capacity, and energy density under all current densities tested. At 10 mA cm-2, the energy density of Mg-1Sn is 1239.621 mWh g-1, which is higher than the Mg-5Sn anode and Mg-9Sn anode, 37% and 25%, respectively. The optimal discharge performance of the Mg-1Sn anode is mainly attributed to the high electrochemical activity and the micron-sized Mg2Sn phase dispersed in the matrix, which facilitates more uniform dissolution.

Corrosion behavior of Mg-1Sn anode for primary Magnesium batteries

“…Mg-14Sn alloy shows different electrochemical behavior of Mg stripping/platting. This result is obtained due to the formation of the eutectic phase [7].…”

“…As a supplement for anode material, Magnesium has started to use for Mg-ion rechargeable batteries (MRBs), but MRB development is constrained by the undesirable passivation layer between Mg and electrolyte. Magnesium anodes have the benefits of a very negative potential (−2.37 V vs. standard hydrogen electrode, SHE), a low density (1.74 g cm −3 ) and a high Faradic capacity (2.2 Ah g −1 ) [7]. Adding Sn to the Mg-Zn alloy significantly increases the specific capacity and the anodic efficiency of the Mg-Zn anode.…”

Effect of Sn/Ca Mass Ratio on the Second Phase, Corrosion Behavior and Discharge Performance of Mg–xSn–1Ca Mg–Air Battery Anodes

“…[19][20][21] Sn has been widely used due to its high theoretical specific capacity and low reaction voltage, leading to the formation of the Mg 2 Sn phase, which also has a high theoretical specific capacity and offers good electrochemical activity. 10,[22][23][24] However, while large amounts of the Mg 2 Sn phase in the Mg anode can facilitate corrosion, an optimal amount can increase the corrosion resistance and anode efficiency of the alloy. 25,26 Additionally, the Mg-1Sn alloy has been found to show the highest discharge capacity, which is mainly attributed to high electrochemical activity and the well-dispersed nanometric Mg 2 Sn phase in the Mg matrix.…”

“…25,26 Additionally, the Mg-1Sn alloy has been found to show the highest discharge capacity, which is mainly attributed to high electrochemical activity and the well-dispersed nanometric Mg 2 Sn phase in the Mg matrix. 22 For instance, Wang et al 21 reported that the galvanic corrosion between the CaMgSn phase and the Mg matrix typically causes pitting corrosion in Mg-3Sn-1Ca-0.3 (Y, La) alloys. However, Song et al 27 found that on Ce addition in Mg-6Al alloy, the formation of a larger γ-(Al 4 Ce) phase could hinder the shedding of discharge products.…”

In Situ Synthesis of AgCl@Ag Plates as Binder-Free Cathodes in a Magnesium Seawater-Activated Battery

“…2,3 The anode for seawater-activated batteries is mainly composed of magnesium alloy due to its negative electrode potential (−2.37 V vs SHE), low hydrogen evolution rate and high anode utilization. 4,5 According to the different cathode materials used for magnesium seawater-activated primary batteries, they can be classified into magnesium-hydrogen peroxide (Mg-H 2 O 2 ) batteries, magnesium-dissolved oxygen seawater batteries, magnesium-air batteries and magnesium-halide (Mg-halide) seawater-activated batteries. [6][7][8][9] Among them, Mg-halide seawater-activated batteries can discharge stably for a long time at low current densities (e.g.…”