阅读说明：本技术 一种镁空气电池用多元合金阳极材料及其制备方法 (Multi-element alloy anode material for magnesium air battery and preparation method thereof ) 是由 万晓峰 汪徐 周井玲 钱双庆 程海正 张福豹 于 2021-07-19 设计创作，主要内容包括：本发明涉及一种镁空气电池用多元合金阳极材料及其制备方法。所述合金阳极材料的化学成分为：铝、镓、铟、锡、锰；锶、钙或钛中的一种或几种；杂质元素；以及镁。制备方法是先取纯镁、铝锭,Al-10Mn中间合金、Mg-27Sr/Mg-30Ca中间合金、Al-10Ti中间合金,锡、镓和铟纯金属原料,预热后依次放入坩埚内熔化,将熔化后的金属液在水冷铜模中浇铸成锭,然后将铸锭经固溶处理后制成镁阳极板。合金阳极材料中形成的粒状Mg-(5)(In-(x)Ga-(1-x))-(2)与Mg-(2)Sn相协同抑制了阳极的析氢副反应并加速了放电产物从镁阳极表面剥落,维持了高放电活性；同时微量锶、钙和钛元素与固溶处理进一步细化组织并改善了镁基体中第二相分布,促进了阳极均匀溶解,提高了阳极利用率。(The invention relates to a multi-element alloy anode material for a magnesium air battery and a preparation method thereof. The alloy anode material comprises the following chemical components: aluminum, gallium, indium, tin, manganese; one or more of strontium, calcium or titanium; impurity elements; and magnesium. The preparation method comprises preheating pure magnesium, aluminum ingot, Al-10Mn intermediate alloy, Mg-27Sr/Mg-30Ca intermediate alloy, Al-10Ti intermediate alloy, and pure metal raw materials of tin, gallium and indium, sequentially melting in a crucible, and meltingThe molten metal is cast into ingots in a water-cooling copper die, and then the ingots are subjected to solution treatment to prepare the magnesium anode plate. Particulate Mg formed in alloy anode materials 5 (In x Ga 1‑x ) 2 With Mg 2 The Sn phase synergistically inhibits the hydrogen evolution side reaction of the anode and accelerates the peeling of a discharge product from the surface of the magnesium anode, and high discharge activity is maintained; meanwhile, the micro strontium, calcium and titanium elements and the solution treatment further refine the structure and improve the distribution of a second phase in a magnesium matrix, promote the uniform dissolution of the anode and improve the utilization rate of the anode.)

1. A multi-element alloy anode material for a magnesium air battery is characterized in that: the weight percentage of the chemical components is as follows:

3% -6% of aluminum;

1% -3% of gallium;

0.5 to 1.5 percent of indium;

0.5 to 1.5 percent of tin;

0.2 to 0.4 percent of manganese;

one or more of strontium, calcium or titanium, wherein:

0.2 to 0.6 percent of strontium

0.1 to 0.5 percent of calcium

0.005% -0.015% of titanium;

1-3% of magnesium alloy refining agent;

impurity elements: iron is less than 0.005%, copper is less than 0.015%, nickel is less than 0.002%, and the total amount of all impurity elements is less than 0.025%;

the balance being magnesium.

2. The multi-element alloy anode material for a magnesium-air battery according to claim 1, wherein: the magnesium alloy refining agent mainly comprises magnesium chloride and potassium chloride.

3. The multi-element alloy anode material for a magnesium-air battery according to claim 1, wherein: the mass percent of the titanium is 0.008% -0.012%.

4. The method for preparing the multicomponent alloy anode material for the magnesium-air battery as recited in claim 1, characterized in that: the method comprises the following steps:

s1, cleaning and descaling raw materials of a magnesium ingot, an aluminum ingot, an Al-10Mn intermediate alloy, an Mg-27Sr intermediate alloy, an Mg-30Ca intermediate alloy, an Al-10Ti intermediate alloy, tin metal, gallium metal and indium metal before use;

s2, cleaning the steel crucible and the smelting tool, and preheating to 200-300 ℃ to spray paint; cleaning and preheating an ingot mould to 120-150 ℃ before use, cooling to 70-80 ℃, spraying a layer of coating with the thickness of 0.1mm on the surface in contact with molten metal, and preheating to 120-200 ℃ for later use;

s3, preheating the crucible to dark red, filling the preheated magnesium ingot and aluminum ingot, covering a protective cover, and introducing 1% SF₆And 99% CO₂Heating and melting the mixed protective gas, and adding Al-10Mn intermediate alloy, Mg-27Sr intermediate alloy/Mg-30 Ca intermediate alloy after the furnace burden is completely melted;

s4, continuously heating the melt to 770-790 ℃, stirring for 1-2 minutes to make the components uniform, then removing surface slag, adding Al-10Ti intermediate alloy, and stirring the melt uniformly again after the melt is completely melted;

s5, cooling the temperature to 730-750 ℃, refining, adding tin metal, gallium metal and indium metal, wrapping pure metal and a part of refining agent by using an aluminum foil, pressing the pure metal and the part of refining agent into the middle-lower part of the melt in the crucible through a bell jar, slightly stirring, simultaneously scattering the other part of refining agent on the surface of the melt, keeping the temperature and standing for 15-20 minutes, skimming surface slag once every 8-10 minutes, and then stirring the melt for 0.5-1 minute;

s6, cooling the melt to 710 ℃, and casting into ingots in a copper mold filled with circulating cooling water;

s7, heating the alloy ingot to 380-420 ℃, carrying out solid solution treatment for 5-8 hours, and carrying out wire cutting to obtain the magnesium anode plate.

5. The method of claim 4, wherein: in step S1, the smelting raw material is preheated in an oven at 150-200 ℃ for 0.5-1 hour.

6. The method of claim 4, wherein: in step S3, the charging sequence of the smelting raw materials is magnesium ingot, aluminum ingot, Al-10Mn intermediate alloy, Mg-27Sr intermediate alloy/Mg-30 Ca intermediate alloy.

7. The method of claim 4, wherein: in step S5, the amount of the refining agent pressed into the melt through the bell jar is 0.5-1% of the weight of the melt, and the amount of the refining agent paved on the surface of the alloy melt is 1-1.5% of the weight of the melt.

8. The method of claim 4, wherein: when pouring is carried out in the step S6, protective gas is introduced into the casting mould from the sprue for 0.5-1 minute, the riser is covered by an asbestos plate, a filter screen is placed below the pouring cup to block oxidation slag inclusion, and 1% SF is continuously conveyed to a liquid flow position during pouring₆And 99% CO₂The mixed gas of (2) is protected.

9. The method of claim 4, wherein: and step S7, during solution treatment, burying the alloy ingot into dry sand, heating the alloy ingot in a box furnace at the temperature of 180-220 ℃, heating the alloy ingot to 380-420 ℃, preserving the heat for 5-8 hours, discharging the alloy ingot out of the furnace, and air cooling the alloy ingot.

Technical Field

The invention belongs to the technical field of metal-air batteries, and particularly relates to a multi-element alloy anode material for a magnesium-air battery and a preparation method thereof.

Background

The problems of insufficient energy supply, excessive exploitation, environmental pollution caused by the use of fossil fuels and the like have brought adverse effects on the development of the current people. The magnesium air fuel cell using magnesium and its alloy as anode material has many advantages of electrochemical performance such as low cost, cleanness, safety, high theoretical voltage and energy density, etc., and is widely paid attention to as potential green clean energy.

Recent research reports that alloying of elements such as gallium and tin can effectively improve the discharge activity and electrochemical performance of the anode material of the metal air fuel cell. The research of Zhang Shuai and the like shows that the increase of the content of the element gallium can shorten the discharge activation time of the Al-Zn-In-Mg-Ga-Sn aluminum alloy anode, increase the open circuit potential negative shift and the current efficiency, and can effectively inhibit the generation of a passive film (Zhang Shuai and the like, electroplating and finishing, 2018, 40(12): 1-6). Yu and the like research that the working potential of Al-Mg-Sn-In alloy is changed to negative by the element gallium under different current densities, the discharge potential of the gallium-containing aluminum alloy anode is obviously reduced compared with the discharge potential of the gallium-free Al-Mg-Sn-In alloy anode, and the discharge activity of the alloy anode is improved (Kun Yu et Al trans. Nonferrous Met. Soc. China, 2015(25): 3747-3752). Li and the like research on indium alloying in Mg-Al-Zn-Ga alloy anode₁₇Al₁₂The uniform distribution of the anode can effectively activate the Mg-Al-Zn-Ga-In anode, so that the alloy anode is corroded and the discharge potential is negatively shifted, and the anode efficiency is obviously improvedJiarun Li et al. Journal of Materials Science &Technology Volume 2020(41): 33-42). Feng and other researches show that the corrosion resistance of Mg-xIn (x = 0-0.8%) and Mg-0.8% In-xGa (x = 0-0.8%) magnesium alloy anodes is improved by adding alloy elements In and Ga, the electrochemical activity of Mg-In alloy is promoted by adding Ga, the average potential of Mg-0.8% In-0.8% Ga alloy is negative to-1.682V at most, the potential is more negative than-1.406V of AZ91D alloy, and the corrosion type of Mg-In-Ga alloy In the discharging process presents uniform and complete corrosion (Yan Feng et al trans. Nonferrous Met. Soc. China, 2013(09): 2650-.

Researches such as Hucheng and the like show that in the homogenized and annealed Mg-6Al-5Pb-0.6Ce alloy anode material, the effective cathode phase (beta-Mg)₁₇Al₁₂Phase) is eliminated, so that the galvanic corrosion of the alloy is reduced, and the corrosion resistance is improved; after the homogenizing annealing, the average discharge potential of the alloy is positively shifted from-1.756V to-1.726V, the discharge activity is slightly weakened, and the anode utilization rate is improved by 5.1 percent to 79.8 percent (Hucheng et al corrosion and protection, 2016, 37(3): 183-. The research of Khaki and the like shows that the anode material of the Mg-6Al-5Pb-1Zn-0.3Mn alloy is beta-Mg along with the prolonging of the solid solution time₁₇Al₁₂The corrosion resistance of the alloy is improved due to the reduction of the intermediate phase, and the discharge performance of the alloy is improved due to the increase of the solid solubility of the alloy elements; during the discharging process, the discharging product layer continuously falls off, and the discharging activity of the magnesium alloy anode is maintained (Khaki et al, school of the university of China (Nature science edition), 2012, 43(10): 3785-. Chinese patent (202010441644. X) discloses a preparation method of Mg-Zn-Ca magnesium air battery anode material with excellent discharge performance provided by traditional casting process, which effectively relieves hydrogen evolution reaction of anode in electrolyte solution by changing atomic ratio of element Zn/Ca in the material, and makes the anode material have point-shaped Ca₂Mg₆Zn₃The formation position of the phase optimizes the discharge process, reduces the accumulation thickness of discharge products on the surface of the anode and accelerates the falling of the products.

However, on the basis of the traditional commercial Mg-Al magnesium alloy anode material, the problems of uniform activation dissolution, product film enrichment and the like in the working process of the battery are solved by adopting the multi-element composite addition of the elements of gallium, indium and tin, and by the synergistic regulation and control of trace elements of strontium, calcium and titanium and solid solution treatment and by fully utilizing the influence of alloy elements and heat treatment on precipitated phases, and no literature report exists.

Disclosure of Invention

The invention provides a multi-element alloy anode material for a magnesium air battery and a preparation method thereof, aiming at the problems of insufficient discharge activity and utilization rate of the traditional anode material for the magnesium air fuel battery, high cost and poor environmental protection caused by harmful elements such as lead, thallium, mercury and the like, so that the peeling of a discharge product from the surface of a magnesium anode is accelerated, the stronger discharge activity of an electrode is maintained, the hydrogen evolution side reaction of the anode is inhibited, and the utilization rate of the anode is improved.

The invention also aims to provide a preparation method of the multi-element alloy anode material for the magnesium air battery.

In order to achieve the purpose, the invention adopts the following technical scheme:

a multi-element alloy anode material for a magnesium air battery comprises the following chemical components in percentage by mass:

3% -6% of aluminum;

1% -3% of gallium;

0.5 to 1.5 percent of indium;

0.5 to 1.5 percent of tin;

0.2 to 0.4 percent of manganese;

one or more of strontium, calcium or titanium, wherein:

0.2 to 0.6 percent of strontium

0.1 to 0.5 percent of calcium

0.005% -0.015% of titanium;

1-3% of magnesium alloy refining agent;

impurity elements: iron is less than 0.005%, copper is less than 0.015%, nickel is less than 0.002%, and the total amount of all impurity elements is less than 0.025%;

the balance being magnesium.

Further, the main components of the magnesium alloy refining agent are magnesium chloride and potassium chloride.

Further, the mass percent of the titanium is 0.008% -0.012%.

The preparation method of the multi-element alloy anode material for the magnesium air battery comprises the following steps:

s1, cleaning and descaling raw materials of a magnesium ingot, an aluminum ingot, an Al-10Mn intermediate alloy, an Mg-27Sr intermediate alloy, an Mg-30Ca intermediate alloy, an Al-10Ti intermediate alloy, tin metal, gallium metal and indium metal before use;

s2, cleaning the steel crucible and the smelting tool, and preheating to 200-300 ℃ to spray paint; cleaning and preheating an ingot mould to 120-150 ℃ before use, cooling to 70-80 ℃, spraying a layer of coating with the thickness of 0.1mm on the surface in contact with molten metal, and preheating to 120-200 ℃ for later use;

s3, preheating the crucible to dark red, filling the preheated magnesium ingot and aluminum ingot, covering a protective cover, and introducing 1% SF₆And 99% CO₂Heating and melting the mixed protective gas, and adding Al-10Mn intermediate alloy, Mg-27Sr intermediate alloy/Mg-30 Ca intermediate alloy after the furnace burden is completely melted;

s4, continuously heating the melt to 770-790 ℃, stirring for 1-2 minutes to make the components uniform, then removing surface slag, adding Al-10Ti intermediate alloy, and stirring the melt uniformly again after the melt is completely melted;

s5, cooling the temperature to 730-750 ℃, refining, adding tin metal, gallium metal and indium metal, wrapping pure metal and a part of refining agent by using an aluminum foil, pressing the pure metal and the part of refining agent into the middle-lower part of the melt in the crucible through a bell jar, slightly stirring, simultaneously scattering the other part of refining agent on the surface of the melt, keeping the temperature and standing for 15-20 minutes, skimming surface slag once every 8-10 minutes, and then stirring the melt for 0.5-1 minute;

s6, cooling the melt to 710 ℃, and casting into ingots in a copper mold filled with circulating cooling water;

s7, heating the alloy ingot to 380-420 ℃, carrying out solid solution treatment for 5-8 hours, and carrying out wire cutting to obtain the magnesium anode plate.

Further, in step S1, the smelting raw material is preheated in an oven at 150-200 ℃ for 0.5-1 hour.

Further, in step S3, the charging order of the melting raw materials is magnesium ingot, aluminum ingot, Al-10Mn master alloy, Mg-27Sr master alloy/Mg-30 Ca master alloy.

Further, in step S5, the amount of the refining agent pressed into the melt through the bell jar is 0.5-1% of the weight of the melt, and the amount of the refining agent spread on the surface of the alloy melt is 1-1.5%.

Further, in the step S6, when pouring, protective gas is introduced into the casting mold from the sprue for 0.5-1 minute, the riser is covered by an asbestos plate, a filter screen is placed under the pouring cup to block oxidation slag inclusion, and 1% SF is continuously conveyed to the liquid flow during pouring₆And 99% CO₂The mixed gas of (2) is protected.

Further, in the step S7, during solution treatment, the alloy cast ingot is buried in dry sand and is placed at the temperature of 180-220 DEG C^oC, heating in a box furnace to 380-420 DEG^oAnd C, keeping the temperature for 5-8 hours, and then discharging from the furnace for air cooling.

The principle of the invention is as follows:

(1) the addition of a proper amount of alloy element manganese can improve the corrosion resistance of the magnesium alloy and reduce the self-corrosion hydrogen evolution reaction of the magnesium alloy.

(2) The alkali metal elements of calcium and strontium have standard electrode potential more negative than that of magnesium, belong to surface active elements, and can be added to improve the discharge voltage of magnesium anode, refine crystal grains and inhibit Mg₁₇Al₁₂And (4) forming a grain boundary phase. The trace titanium also has an obvious refining effect on the structure grain size, and can improve the utilization rate of the magnesium air battery anode.

(3) When a proper amount of elements of gallium and indium are added, short strip-shaped Mg which is dispersed and distributed and can inhibit hydrogen evolution side reaction of a magnesium anode can be formed₅Ga₂Mg of structure₅(In_xGa_1-x)₂Phase, composite addition of elemental tin, forming particulate Mg promoting discharge activity₂The formation of Sn phase can obviously refine Mg₅(In_xGa_1-x)₂Phase organization. When optimizing the tin content, Mg₅(In_xGa_1-x)₂The precipitated form of the phases is dispersed fine dots, and when the addition amount of calcium and strontium is optimized, the precipitated form of the phases is a network structure distributed along the grain boundary. The solid solution treatment can further optimize the element content in the magnesium matrix and the distribution and the quantity of precipitated phases to obtain the discharge activity and the positiveThe polar utilization matches well-matched tissue. The magnesium air battery anode material with excellent discharge performance is finally obtained by adjusting the element proportion and the heat treatment process.

Compared with the prior art, the invention has the advantages that:

1. based on the traditional commercial low-cost Mg-Al series magnesium alloy anode material, the multi-element composite addition of gallium, indium and tin is adopted, and punctiform or granular Mg is formed in an alloy structure₅(In_xGa_1-x)₂With Mg₂The Sn phase accelerates the stripping of the discharge product from the surface of the magnesium anode in cooperation, effectively eliminates the adverse effect of corrosion products such as a passive film, a magnesium salt and the like attached to the surface of the anode on the active dissolution of the magnesium anode in the discharge process, and maintains the stronger discharge activity of the electrode.

2. The method considers the synergistic regulation and control of trace strontium, calcium and titanium elements and the solid solution treatment, fully utilizes the influence of alloy elements and heat treatment on precipitated phases, further refines the structure, improves the distribution of a second phase in a magnesium matrix, inhibits the hydrogen evolution side reaction of the anode, improves the utilization rate of the anode, and has simple preparation process and convenient implementation.

Drawings

FIG. 1 shows the compositional phase XRD pattern (a) and the metallographic microstructure (b) of the sample of the magnesium anode of example 3.

FIG. 2 shows the magnesium anode of example 3 at 30mA/cm²The surface appearance of the anode is obtained after constant current discharge for 4h under the current density.

FIG. 3 is a graph of hydrogen evolution versus time for the magnesium anode materials of examples 1-3 in a 3.5wt% NaCl solution and compared to AZ61 alloy.

FIG. 4 shows the results of examples 1 to 3 in which the magnesium anode materials were each at 10mA/cm²And 30mA/cm²The discharge current was discharged for 600S and compared to AZ61 alloy.

Detailed Description

The technical solution of the present invention is further described below with reference to the following embodiments and the accompanying drawings.

Example 1

Taking Mg-4Al-0.5Ga-1In-1Sn-0.2Ca-0.2Mn alloy as an example

The materials are prepared according to the following mass percentages:

4% of aluminum;

0.5% of gallium;

1% of indium;

1% of tin;

0.2 percent of calcium;

0.2 percent of manganese;

the balance being Mg.

S1, preparing raw materials:

the raw materials are suitably treated and cleaned to remove corrosion and solvents, grit, scale etc. from the surface to prevent them from reacting with the magnesium solution and silicon, iron, hydrogen, oxide inclusions etc. from entering the solution. The treatment method mainly combines sand blowing, mechanical polishing and chemical acid-base washing. All raw materials are baked in an oven for 20-30 minutes at the temperature of about 150 ℃ before smelting so as to remove contained water vapor.

S2, preparation:

the casting mould is made of a top-pouring water-cooling copper mould, and the diameter of the casting mould is 60 mm. Cleaning the die before use, preheating the die to 120-150 ℃, cooling to 70-80 ℃, spraying the coating, and then preheating to 120-200 ℃ for later use. The mould coating is mainly prepared from talcum powder, boric acid, water glass and water with the temperature of 60 ℃.

Cleaning a smelting tool (mainly removing rust), preheating to 200-300 ℃ to spray paint, wherein the paint is mainly prepared from chalk powder, graphite powder, boric acid, water glass and water at 60 ℃.

All the moulds are preheated by heating to 200 ℃ in an oven.

In the smelting process, all elements have oxidation burning loss, volatilization and melting loss of different degrees. When in burdening, the adding amount is increased according to a certain proportion, and the specific burdening rate is as follows: 3% -4% of aluminum; 35% -40% of gallium; 35% -40% of indium; 35% -40% of tin; 25 to 30 percent of calcium; 25 to 30 percent of strontium; 1% -3% of titanium; 2 to 3 percent of manganese.

Preparing a crucible: the crucible material is low carbon steel. The new crucible is used after kerosene penetration and X-ray inspection before use prove that the crucible has no leakage and defects influencing use, and the old crucible is checked to be intact after slag and oxide scale are removed.

Preparation:

(1) preheating the crucible to dark red, filling the preheated magnesium ingot and aluminum ingot, covering the crucible with a protective cover, and introducing 1% SF₆ + 99%CO₂Mixing protective gas, heating and melting;

(2) the temperature of the furnace is raised to 770 ℃, after the charged furnace materials are completely melted, the mixture is stirred for 0.5 minute to ensure that the components are uniform, and then surface slag is removed. Adding preheated Al-10Mn intermediate alloy, sequentially adding Mg-27Sr or Mg-30Ca intermediate alloy after the intermediate alloy is completely melted, stirring for 0.5 minute after the intermediate alloy is melted to make the components uniform, and then removing surface slag;

(3) cooling to 730 deg.C, refining, adding pure metal of Sn, Ga and in, the refining agent accounting for 1% of the weight of the melt, wrapping the refining agent and the pure metal with aluminum foil, pressing into the middle-lower part of the melt in the crucible through a bell jar, slightly stirring, continuously scattering magnesium alloy refining agent whose main components are magnesium chloride and potassium chloride on the surface of the melt, the scattering amount on the surface of the alloy melt is 1%. Refining until the surface of the melt is not coated with white slag and presents a bright mirror surface. Keeping the temperature and standing for 20 minutes, skimming surface slag about every 8 minutes, and then stirring the melt for 0.5 minute;

(4) and (3) when the temperature of the melt is reduced to about 710 ℃, pouring in a copper mold filled with circulating cooling water, introducing protective gas into the casting mold from a sprue for 1 minute, and covering a dead head with an asbestos plate. Meanwhile, a filter screen is placed under the pouring cup to block oxidation slag inclusion, protective gas is continuously conveyed to a liquid flow position for protection during pouring, and the alloy is prepared after cooling and solidification.

Solution heat treatment:

heating the alloy cast ingot to 420 ℃, carrying out solid solution treatment for 4 hours, carrying out cooling treatment by adopting normal-temperature water as a medium, and carrying out wire cutting to obtain the magnesium anode plate.

Example 2

Taking Mg-5Al-1Ga-1In-1Sn-0.2Ca-0.3Sr-0.2Mn alloy as an example

The materials are prepared according to the following mass percentages:

5% of aluminum;

1% of gallium;

1% of indium;

1% of tin;

0.2 percent of calcium;

0.3 percent of strontium;

0.2 percent of manganese;

the balance being Mg.

The preparation and implementation were the same as in example 1, in which: (4) in the step, the refining temperature is 740 ℃, the total consumption of the refining agent is 1.5%, the melt after refining is kept stand for 15 minutes, and surface slag is skimmed off every 5 minutes.

Solution heat treatment:

heating the alloy cast ingot to 400 ℃, carrying out solid solution treatment for 6 hours, carrying out cooling treatment by adopting normal-temperature water as a medium, and carrying out wire cutting to obtain the magnesium anode plate.

Example 3

Taking Mg-6Al-2Ga-1In-1Sn-0.2Ca-0.3Sr-0.01Ti-0.2Mn alloy as an example

The materials are prepared according to the following mass percentages:

6% of aluminum;

2% of gallium;

1% of indium;

1% of tin;

0.2 percent of calcium;

0.3 percent of strontium;

0.01 percent of titanium;

0.2 percent of manganese;

the balance being Mg

The preparation and implementation were the same as in example 1, in which:

in the preparation stage, before the step of adding pure metals of tin, gallium and indium for refining, Al-10Ti intermediate alloy is added, and the specific process is as follows: and (3) continuously heating the melt to 780 ℃, stirring for 1-2 minutes to make the components uniform, and then removing surface slag. Adding Al-10Ti intermediate alloy. After all the melt is melted, the melt is stirred uniformly again.

The temperature of the refining step is 750 ℃, the total amount of the refining agent is 1.5%, the melt after refining is kept still for 15 minutes, and surface slag is skimmed off about every 5 minutes.

Solution heat treatment:

heating the alloy cast ingot to 380 ℃, carrying out solid solution treatment for 8 hours, carrying out cooling treatment by adopting normal-temperature water as a medium, and carrying out wire cutting to obtain the magnesium anode plate.

Mg-6Al-2Ga-1In-1Sn-0.2Ca-0.3Sr-0.01Ti-0.2Mn alloy is taken as a magnesium anode material, and a composition phase XRD (X-ray diffraction) spectrum (a) and a sample metallographic microstructure (b) of the magnesium anode structure are shown In figure 1. The results show that the ternary fine-grained Mg in the tissue₅(In_xGa_1-x)₂Mesophase and punctate Mg₂The Sn phase is obviously increased, and Mg is at the dendritic crystal boundary₁₇Al₁₂Most phases do not form massive or strip-shaped tissue phases distributed in a continuous net shape, and are still dispersed and distributed in the alloy matrix phase in a short granular shape, and the addition of trace elements and heat treatment play a role in obviously refining the intermediate phase. FIG. 2 shows 30mA/cm²The surface appearance of the anode is obtained after constant current discharge for 4h under the current density, the magnesium anode surface discharge product is thin and in an irregular crack shape, and a part of the anode surface area is stripped in the discharge process, which shows that the electrolyte can be timely and effectively contacted with the magnesium anode surface in the discharge process, so that the anode can maintain high activity and stable discharge potential.

Compared with the hydrogen evolution rate curve and the constant current discharging curve of the traditional commercial AZ61 alloy anode, the multielement alloy anode material for the magnesium air battery of the invention has the advantages that:

examples 1-3 magnesium anode materials the hydrogen evolution versus time curve in a 3.5wt% NaCl solution and comparison with AZ61 alloy anodes is shown in figure 3 below. As can be seen from fig. 3: under the condition of room temperature, the hydrogen evolution rate of the magnesium anode materials in the examples 1 to 3 in the electrolyte solution is lower than that of an AZ61 alloy anode, wherein the hydrogen evolution rate of the magnesium anode material in the example 3 is lower than that of other materials, which shows that the alloy of the invention has good performance of inhibiting the hydrogen evolution side reaction and is easy to obtain higher anode utilization rate. The magnesium anode material of the invention is respectively 10mA/cm²And 30mA/cm²The discharge curve of discharging 600S at discharge current and comparing with the performance of AZ61 alloy are shown in FIG. 4. As can be seen from the constant current discharge curve of FIG. 4, the magnesium anode materials of examples 1-3 of the present invention have more negative discharge potentials at two current densities compared to AZ61 alloy, and the examples of the present invention maintain stable and more negative discharge potentials with the increase of discharge time, wherein the magnesium anodes of examples 2 and 3 have more negative discharge potentialsThe negative shift of the discharge potential of the electrode material is obvious, which shows that the magnesium anode of the invention can have higher discharge activity in the discharge process.

Therefore, through the combination of proper proportioning of several alloy elements and a heat treatment process, the magnesium air battery anode material with excellent discharge performance is developed. Although preferred embodiments have been depicted and described in detail herein, it will be apparent to those skilled in the relevant art that various modifications, additions, substitutions and the like can be made without departing from the spirit of the invention and these are therefore considered to be within the scope of the invention as defined in the following claims.