The grain size and Mg2Ca morphologies of Mg–1Sn–1Ca-0.3Mn (TX11) alloy are tailored using different cooling methods (furnace cooled, air cooled, oil cooled and water cooled). Optical microscopy (OM) ...and scanning electron microscopy (SEM) are used to observe the microstructure, and the electrochemistry workstation and Mg-air battery tests are used to investigate the electrochemical corrosion behaviors and Mg-air battery anodic performance. The results reveal that cooling methods lead to refine grain and the Mg2Ca-phase morphology changed from linear-like shape to needle-like shape. The linear-Mg2Ca phase induced by furnace cooled is beneficial for improving electrochemical activity and discharge voltage during the discharge process. Among all TX11 alloy, the average discharge voltage of furnace-cooled TX11 alloy reaches 1.163V at a current density of 20 mA cm−2. In addition, the small grain and uniform distribution round-shape Mg2Ca phase prepared via oil cooled leads to the alloy best corrosion resistance and best comprehensive discharge performance, with the average discharge voltage, anodic efficiency, specific capacity and specific energy of 1.152V, 57.8%, 1290.3 mA h g−1 and 1487.5 mW h g−1 at 20 mA cm−2 among four alloys, respectively. The cooling methods provide a new idea for improving the comprehensive discharge performance of Mg-air battery anodes.
•TX11 alloy are tailored using different cooling methods in the first time.•Effect of grain size and Mg2Ca morphology on anode performance is investigated.•OC-TX11 Mg-air battery anode exhibits good comprehensive discharge performance.•Cooling methods provide a new idea for improving Mg-air battery anode performance.
Magnesium (Mg) is abundant, green and low-cost element. Magnesium-air (Mg-air) battery has been used as disposable lighting power supply, emergency and reserve batteries. It is also one of the ...potential electrical energy storage devices for future electric vehicles (EVs) and portable electronic devices, because of its high theoretical energy density (6.8 kWh•kg−1) and environmental-friendliness. However, the practical application of Mg-air batteries is limited due to the low anodic efficiency of Mg metal anode and sluggish oxygen reduction reaction of air cathode.
Mg metal as an anode material is facing two main challenges: high self-corrosion rate and formation of a passivation layer Mg(OH)2 which reduces the active surface area. In last decades, a number of Mg alloys, including Mg-Ca, Mg-Zn, commercial Mg-Al-Zn, Mg-Al-Mn, and Mg-Al-Pb alloys, have been studied as anode materials for Mg-air batteries. This article reviews the effect of alloying elements on the battery discharge properties of Mg alloy anodes. The challenges of Mg-air batteries are also discussed, aiming to provide a depth understanding for the theoretical and practical development of high-performance Mg-air batteries.
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•Mg anode in NaAc electrolyte exhibits uniform dissolution behavior.•Sufficiently inhibit the anodic hydrogen evolution corrosion of Mg anode.•Enhance the utilization efficiency of Mg ...anode up to 84% at 10 mA cm−2.•NaAc electrolyte is applied in a commercial Mg air battery.•Verify the anodic corrosion of Mg is related to its localized passive film rupture.
Aqueous magnesium air batteries are promising energy conversion devices because of high theoretical energy density, inherent safety and low cost. However, their practical energy density is significantly limited due to the dramatic hydrogen evolution corrosion of Mg anode in conventional sodium chloride (NaCl) electrolyte. Herein, we suppress the hydrogen evolution reaction on the surface of Mg anode using sodium acetate (NaAc) electrolyte, in which Mg anode exhibits uniform anodic dissolution behavior without the notorious localized corrosion. It is demonstrated that acetate ion (Ac-) averts the localized passive film breakdown of Mg anode in virtue of its large diffusion energy barrier within the film. Therefore, the anodic hydrogen evolution phenomenon amid discharge is evidently repressed. This enables Mg anode to achieve a high utilization efficiency of 84 % at 10 mA cm−2 compared with 59 % in NaCl electrolyte. Mg air battery tests manifest that its specific energy based on the anode weight is boosted from 1370 to 1770 Wh kg−1. Finally, the practicality of NaAc electrolyte is confirmed in a commercial Mg air battery. This work provides a simple and scalable solution for high performance Mg air battery.
This work investigates the performance of magnesium (Mg) - air battery with modified AZ31 anode, designated as AZ31M. It successfully achieves a high anodic efficiency of 73% with the energy density ...of 1692 mWh g−1 and capacity of 1582 mAh g−1 at 1 mA cm−2 in 3.5% NaCl. These battery parameters are higher than those reported for most Mg anodes. The addition of the cost-effective La, Ce and Ca refines the bulk Mg17Al12 in AZ31 into small Mg17Al12, Al2Ca and Al2(Ca, RE), leading to a uniform discharge with slight galvanic corrosion and low anode delamination effect. The AZ31M anode is a potential candidate Mg anode for wide application of Mg-air battery.
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•The AZ31M has homogeneous microstructure with fine second phases distributed uniformly in the matrix.•The Mg-air battery achieves an anodic efficiency of 73% with the energy density of 1692 mWh g−1 at 1 mA cm−2 in 3.5% NaCl.•The corrosion rate of AZ31M is 0.38 ± 0.09 mm y−1 in 3.5 wt% NaCl.•The AZ31M anode is a potential candidate Mg anode for wide application of Mg-air battery.
Rechargeable Mg–air batteries are a promising alternative to Li–air cells owing to the safety, low price originating from the abundant resource on the earth, and high theoretical volumetric density ...(3832 A h L−1 for Mg anode vs 2062 A h L−1 for Li). Only a few works are related to the highly reversible Mg–air batteries. The fundamental scientific difficulties hindering the rapid development of secondary Mg–air cells are attributed to the poor thermodynamics and kinetics properties mainly owing to the MgO or MgO2 insulating film as the initial discharge product on air–breathing cathode, contributing to the increase of a large overpotential and a high polarization. Very recently, remarkable progress on rechargeable Mg–air batteries is trying to overcome the major limitations in organic electrolytes via the combination of the first–principle calculation and experimental study. Therefore, this progress report highlights a comprehensive and concise survey of the major progress in the history of secondary Mg–air batteries, and the detailed illustrations of corresponding reaction mechanisms. The overview is devoted to open up a new area for manipulating the nanostructures to control the ideal reaction pathway in novel cell configuration and to fully understand the future Mg–air battery with improved energy density and cycling ability.
Rechargeable Mg–air batteries process a high theoretical volumetric density and energy density, but still certain fundamental scientific issues remain, hindering the developments of practical applications. This progress report is devoted to summarize the current progress in the history and to provide possible pathways for future investigations to enhance the cycling retention properties.
In this work, the role of grain structures in tailoring the electrochemical behaviors and discharge performances of extruded lean Mg-0.3Bi-0.3Ag-0.3In (wt.%) alloys with different extrusion ratios ...(ER) of 9 and 36 is systemically investigated. Results indicate the ER9 sample exhibits a typical bimodal microstructure comprising equiaxed grains and elongated deformed grains, whereas the ER36 sample shows a fully dynamic recrystallized grain structure. The fine-equiaxed grain structure with low kernel average misorientation and texture intensity values in the ER36 anode is conducive to increase the kinetics of anode dissolution and promote the formation of loose and thin discharge products layer, resulting in a higher and steadier cell voltage. The Mg-air battery assumed by the ER36 anode presents a high cell voltage, considerable anodic efficiency, and specific energy of 1.3676 V, 60.63%, and 1807.79 mW h g−1, respectively, at 10 mA cm−2, which are attributed to the even dissolution of the anode as well as the suppression of the chunk effect and hydrogen evolution, thereby making the ER36 alloy as a potential anode material for primary Mg-air batteries.
•The dependence of anode performances on the grain structure is investigated.•The different grain structures are achieved by adjusting the extrusion ratio.•More negative open circuit potentials are obtained in ER36 sample.•Real-time hydrogen evolution rate and chunk effect are suppressed in ER36 sample.•Homogeneous anodic dissolution is activated in ER36 sample.
In order to decrease the corrosion rate of magnesium anode and increase the discharge property of magnesium-air battery, a water soluble graphene poly (sodium 4-styrenesulfonate)/reduced graphene ...oxide and a reduced graphene oxide/Mn3O4 nanometer composite are prepared successfully. They are used to assemble a magnesium-air battery with a poly (sodium 4-styrenesulfonate)/reduced graphene oxide based NaCl electrolyte and a reduced graphene oxide/Mn3O4 nanometer composite as cathode catalyst. The structures and morphologies of poly (sodium 4-styrenesulfonate)/reduced graphene oxide and reduced graphene oxide/Mn3O4 nanometer composite are tested by x-ray diffraction, scanning electron microscope and fourier transform infrared spectrophotometer. The assembled magnesium-air battery with poly (sodium 4-styrenesulfonate)/reduced graphene oxide and reduced graphene oxide/Mn3O4 nanometer composite has been found to possess an energy density of 1620 Wh kg−1 and an anode utilization of 82%, much higher than those achieved with a NaCl solution and a commercial air cathode (1115 Wh kg−1 and 52%).
•The energy density of Mg-air battery with PSS/RGO and RGO/Mn3O4 is 1620 Wh kg−1.•The anodic utilization of Mg-air battery with PSS/RGO and RGO/Mn3O4 is 82%.•PSS/RGO improves the electrochemical activity and decreases the corrosion rate.
When designing a high energy density battery, one of the critical features is a high voltage, high capacity cathode material. In the development of Mg batteries, oxide cathodes that can reversibly ...intercalate Mg, while at the same time being compatible with an electrolyte that can deposit Mg reversibly are rare. Herein, we report the compatibility of Mg anodes with α-V2O5 by employing magnesium bis(trifluoromethane sulfonyl)imide in diglyme electrolytes at very low water levels. Electrolytes that contain a high water level do not reversibly deposit Mg, but interestingly these electrolytes appear to enable much higher capacities for an α-V2O5 cathode. Solid state NMR indicates that the major source of the higher capacity in high water content electrolytes originates from reversible proton insertion. In contrast, we found that lowering the water level of the magnesium bis(trifluoromethane sulfonyl)imide in diglyme electrolyte is critical to achieve reversible Mg deposition and direct evidence for reversible Mg intercalation is shown. Findings we report here elucidate the role of proton intercalation in water-containing electrolytes and clarify numerous conflicting reports of Mg insertion into α-V2O5.
•Demonstrated the critical role of trace water in electrolyte for reversible Mg deposition.•First time report of proton participated intercalation for V2O5.•Clarified misunderstandings from literature about the large capacity observed for V2O5.
In this study, the discharge behaviors of extruded low-alloyed Mg–Bi–Ca alloys in an aqueous electrolyte (3.5 wt% NaCl solution) were investigated using electrochemical techniques. The Mg–1Bi-0.5Ca ...alloy showed more negative discharge potential and higher anodic efficiency compared with the Mg–1Bi alloy during half-cell testing. Furthermore, the discharge morphologies of the Mg–1Bi-0.5Ca alloy showed loose and thin discharge products, along with numerous cracks, these features promoted diffusion of the NaCl solution into the discharge products, enhancing the discharge activity. The Mg–air battery with a Mg–1Bi-0.5Ca anode showed the higher cell voltage and power density at all current densities. Hence, the Mg–1Bi-0.5Ca alloy has great potential for further development as an anode material for Mg–air battery.
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•Discharge properties of Mg–Bi–Ca alloy anode materials for Mg-air batteries were studied.•Addition of 0.5 wt% Ca was beneficial for the formation of the Mg2Bi2Ca phase.•Addition of Ca to Mg–Bi-based alloys led to loose and thin discharge products.•Mg-air battery with Mg–1Bi-0.5Ca anode exhibited superior discharge properties.
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