Mg-3wt%Al anodes with Sn, Ga and In were prepared by melting and heat-treatment in electric resistance furnace. The electrochemical discharge behavior of these anodes in 3.5wt% NaCl solutions was studied by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The microstructures and the corroded surfaces of the anodes were investigated by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). Finally, Mg-air batteries based on Mg-3Al-1Sn (AS31), Mg-3Al-1Ga (AG31), Mg-3Al-1In (AI31) alloys were prepared and battery properties were studied by constant current discharge test. Mg-3Al (A3) and Mg-3Al-1Zn (AZ31) were also prepared to be used for contrast test. The results show AI31 behaves good comprehensive properties, the battery based on AI31 anode possesses the highest capacity density (1382 mAhg−1) and power density (18.5 mWcm−2). Compared with A3 and AZ31, AS31 and AG31 show higher corrosion resistance. In addition, The paper also researches on the modification mechanism of Ga, In and Sn on Mg-3Al.

In this research, the performance of Al-air batteries based on pure Al and Al-0.5 wt%In anodes in 4M NaOH solutions with or without different concentrations of additives was investigated by galvanostatic discharge test. The characteristics of the anodes after discharge were investigated by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and energy dispersive analysis of X-ray (EDAX). The corrosion behavior of the anodes was researched by self-corrosion rate test and potentiodynamic polarization test. The results show that the Al-In alloy exhibits a low self-corrosion rate and high anodic efficiency when ZnO or Na 2 SnO 3 is added to 4M NaOH. The results of galvanostatic discharge at 20 mAcm −2 indicate that the Al-air battery based on Al-0.5 wt%In anode shows excellent discharge performance. The Al-air battery based on the alloy anode has an operating voltage of 1.3 V and anodic efficiency of 75.2% in 4M NaOH with 0.02M Na 2 SnO 3 , and an operating voltage of 1.01 V and anodic efficiency of 82.5% in 4M NaOH with 0.2M ZnO. SEM and EDAX results prove that zinc oxide or sodium stannate could inhibit the corrosion of the Al-In anode by the deposition of zinc or tin on the anode surface.Aluminum is an excellent anode material for metal-air batteries because of its high theoretical electrochemical equivalent value (2980 mAh g -1 ), which is just lower than that of lithium (3860 mAh g -1 ) and higher than those of other metals such as magnesium (2200 mAh g -1 ) and zinc (820 mAh g -1 ). 1 As promising power and energy storage devices, Al-air batteries can be applied in fields such as electric vehicles, navigation and portable sources. In addition, the final reaction product can be recovered as aluminum during recycling. However, severe self-corrosion of the aluminum anode in alkaline electrolyte causes fuel loss during standby. A protective oxide film forms spontaneously on the aluminum surface in neutral electrolyte, which slows down the active dissolution of the aluminum anode. These problems have hindered the development and business applications of Al-air batteries. 2,3 Two main methods have been proposed to inhibit the self-corrosion of aluminum anodes in alkaline solution. The first method is to dope aluminum with active metal elements. The active metal elements mainly include Ga, In, Sn, Zn and Mg. 4 As they have high hydrogen evolution overpotential, these alloying elements can reduce hydrogen evolution. An Al-air battery based on Al-1 wt%Mg-1 wt%Zn-0.1 wt%Ga-0.1 wt%Sn anode in 4M NaOH solution showed excellent discharge performance. 5 However, the addition of excessive kinds of elements is harmful to the recovery of aluminum. What's more, the amount of active metal elements added into the aluminum should be as low as possible. Therefore, researchers preferred to study some binary aluminum alloys as anodes of Al-air batteries. 6-9 For instance, Wilhelmsen studied the corrosion rate of Al-0.1 wt%In anode in 4M KOH solution by the weight loss method and the result revealed that t...

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In this paper, the performance of Al-air batteries based on pure Al, Al-0.1 wt%Ga, Al-0.1 wt%In and Al-0.1 wt%Sn anodes in 1 M KOH solutions was investigated by galvanostatic discharge test. The electrochemical characteristics of the anodes were investigated by means of hydrogen collection, tafel polarization, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM). The results reveal that compared with pure Al in 1 M KOH, Al-0.1 wt%In or Al-0.1 wt%Sn exhibits a lower self-corrosion rate and higher electrochemical activity because indium or tin with a high hydrogen evolution overpotential deposits on the aluminum surface. The Al-0.1 wt%Ga alloy is not an ideal anode of alkaline Al-air battery because the severe self-corrosion. The results of galvanostatic discharge at a current density from 1 to 40 mA cm −2 indicate that the Al-air batteries based on both Al-0.1 wt%In and Al-0.1 wt%Sn anodes in 1 M KOH show excellent discharge performance and high anodic efficiencies.Aluminum is considered an excellent anode material for metal-air batteries, because it is the most abundant crustal metal on the earth and has a high theoretical electrochemical equivalent value (2980 mAh g −1 ) and energy density (8100 Wh Kg −1 ). 1 However, Al-air batteries still encounter many challenges, which have hindered the development of Al-air battery and restrict its business applications. 2,3 For instance, in neutral salt electrolyte, pure aluminum supports a passive film on the surface with an operational potential of approximately −0.8 V (vs. SCE) and a greatly serious polarization during discharge, which makes it useless as a sacrificial anode for Al-air battery. To overcome the problem, many researchers have used high purity grade aluminum alloys doped with such elements as Mg, Ga, In, Sn, which act as corrosion inhibitors without enhancing the overvoltage for aluminum dissolution and can also shift the potential toward more negative values causing the so-called activation of aluminum which is helpful for Al-air battery. 4 According to the previous reports, the potential values of Al-In alloys in neutral salt solution changed from −1.4 V to −1.7 V (vs. SCE) and the corrosion rates of the alloys were decreased compared to pure aluminum. The electrochemical properties of the alloys in 2 M NaCl solution also were studied. The results indicated that the corrosion potentials were around −1.3 V (vs. SCE). 5 The performance of Al-Sn alloy was studied by El Shayeb. The potential value of the alloy in 0.6 M NaCl was around −0.98 V (vs. SCE). In 2 M NaCl solution, the potential value of the alloy shifted more toward the negative which was around −1.45 V (vs. SCE). 6 Some ternary Al alloys were also investigated in 2 M NaCl solution. The potential of Al-In-Sn alloy obtained in 2 M NaCl solution was around −1.46 V vs. SCE). 7 The Al-In-Ga alloy exhibited more negative potential than that of pure Al but slight lower than Al-In alloy. 7 But, these methods just can only resolve the passivation of aluminum limitedly. Addition...

Aluminum is attracting interest due to the good application prospect as anode for metal-air batteries in alkaline solutions. In this paper, the corrosion behavior and electrochemical properties of industrial aluminum alloy are investigated using hydrogen collection method, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in 4 M NaOH and 4 M KOH. Battery performances are tested by constant current discharge at different current densities. The results show 8011 Al alloy has better electrochemical properties, discharge energy and power density. Considering the cost and performance, 8011 Al alloy is one of the most promising low-cost and high performance Al anode for Al-air batteries.