Magnesium-air battery anode material Mg-In-Ca-Y alloy and preparation method thereof

Abstract

This invention relates to the field of chemical power source electrode materials, and discloses a Mg-In-Ca-Y alloy anode material for magnesium-air batteries and its preparation method. The alloy comprises the following mass percentage composition: Mg: 97 wt.%, In: 2 wt.%, Ca: 0.5 wt.%, Y: 0.5 wt.%. The Mg-In-Ca-Y alloy exhibits a finely dispersed second phase, uniformly distributed twins, and columnar-oriented grains. This invention aims to develop high-performance magnesium-air battery anode materials and address the problem of insufficient discharge performance in existing magnesium-air batteries.

Description

Technical Field

[0001] This invention relates to the field of chemical power source electrode materials, specifically to the Mg-In-Ca-Y alloy anode material for magnesium-air batteries and its preparation method. Background Technology

[0002] Magnesium-air batteries are a type of metal fuel cell. Their principle involves using oxygen from the air as the positive electrode active material and metallic magnesium as the negative electrode active material. Oxygen from the air continuously diffuses through the gas diffusion electrode to the electrochemical reaction interface, reacting with the metallic magnesium to release electrical energy. As a clean, safe, and efficient new type of battery, magnesium-air batteries have advantages such as abundant reserves, low price, and simple processing technology. Compared with other types of metal-air batteries (Al, Li, Na, Fe, Zn, etc.), magnesium-air batteries also have many advantages, including a negative standard electrode potential, high theoretical specific capacity, high theoretical discharge voltage, and good overall energy density.

[0003] However, the following problems in the actual use of magnesium-air batteries affect their widespread application: First, because the discharge product magnesium oxide adheres to the surface of the anode material, the discharge voltage is much lower than its theoretical voltage value; second, the self-corrosion of magnesium and magnesium alloys during discharge and the "block effect" caused by some materials detaching from the substrate also greatly reduce the utilization efficiency of magnesium alloy anode materials; finally, the slow cathode kinetics is also a major reason restricting the development of magnesium-air batteries. Summary of the Invention

[0004] The present invention aims to provide a Mg-In-Ca-Y alloy anode material for magnesium-air batteries and its preparation method, so as to develop a high-performance magnesium-air battery anode material and solve the problem of insufficient discharge performance of existing magnesium-air batteries.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a magnesium-air battery anode material Mg-In-Ca-Y alloy, comprising the following mass percentage composition: Mg: 97wt.%, In: 2wt.%, Ca: 0.5wt.%, Y: 0.5wt.%; and the Mg-In-Ca-Y alloy has a finely dispersed second phase, uniformly distributed twins, and columnar oriented grains.

[0006] The beneficial effects of this solution are as follows: Addressing the problem of low discharge performance in magnesium-air battery anode materials, a Mg-In-Ca-Y alloy anode material with excellent discharge performance is prepared using high-purity Mg, In, Ca, and Y metals as raw materials through smelting, solution treatment, and hot extrusion. This alloy achieves a discharge performance of up to 10 mA / cm². 2At the specified current density, a discharge voltage of 1.406V and an anode utilization rate of 55.3% are achieved, demonstrating excellent performance and solving the problem of insufficient discharge performance in existing magnesium-air batteries. It also includes the following beneficial effects:

[0007] 1. By adding trace amounts of Ca and Y elements to the Mg-In alloy, the discharge performance was improved while the material cost was further controlled.

[0008] 2. The second phase Mg2Ca and Mg in this Mg-In-Ca-Y alloy 24 The Y5 phase grains are refined, dispersed, and exhibit a "waterfall-like" appearance, resulting in a large number of uniformly distributed twins and columnar-oriented grains in the alloy, which helps the alloy exhibit high discharge performance.

[0009] 3. Since the potential of the second phase Mg2Ca in this Mg-In-Ca-Y alloy is about 50mV more negative than that of the magnesium matrix, an galvanic corrosion effect will occur between the Mg2Ca phase and the magnesium matrix. The Mg2Ca phase, as the anode of galvanic corrosion, will dissolve before the magnesium matrix during the discharge process. This will further improve the discharge performance of the magnesium alloy by reducing the adsorption force between the discharge products and the matrix and accelerating the shedding of the discharge products.

[0010] 4. Controlling the In content to 2 wt.% can reduce the dendrite spacing of the alloy, thereby further improving the electrochemical activity of the magnesium alloy.

[0011] Preferably, the purity of Mg is greater than 99.9%, the purity of In is greater than 99.9%, the purity of Ca is greater than 99.9%, and the purity of Y is greater than 99.9%.

[0012] Preferably, a method for preparing the Mg-In-Ca-Y alloy anode material for magnesium-air batteries is also provided, comprising the following steps:

[0013] S1, Melting: Under a protective atmosphere, magnesium blocks, pure In, Mg-20Y master alloy and Mg-30Ca master alloy are melted sequentially to obtain an alloy melt; magnesium oxide is removed from the surface of the alloy melt, and an alloy ingot is obtained by condensation treatment.

[0014] S2, solution treatment: The ingot is kept at 400℃ for 24 hours;

[0015] S3, Hot extrusion: The alloy ingot is subjected to hot extrusion treatment; the extrusion temperature is 350℃ and the extrusion ratio is 40:1, resulting in a block material with a thickness of 2mm, which is the Mg-In-Ca-Y alloy, the anode material for magnesium-air batteries.

[0016] Preferably, in S1, the protective gas used in the protective atmosphere is a mixture of CO2 and SF6, and the volume ratio of CO2 to SF6 is 35:1.

[0017] Preferably, in S1, the method for removing magnesium oxide from the surface of the alloy melt is as follows: under a protective gas atmosphere, a refining agent is added to the alloy melt until the surface of the alloy melt reaches a preset standard, and then the addition is stopped.

[0018] Preferably, the refining agent is a mixed solvent of MgCl2, KCl, BaCl2 and CaF2, and the mass ratio of the mixed solvent is MgCl2:KCl:BaCl:CaF2 equals 46:42:8:5.

[0019] Preferably, in S3, before hot extrusion treatment of the alloy ingot, the oxides on the surface of the alloy ingot are removed by grinding, and the ground alloy ingot is preheated at 350°C for 30 minutes.

[0020] Preferably, a magnesium-air battery is also provided, comprising a Mg-In-Ca-Y alloy prepared by the preparation method described in the above scheme as an anode material. Attached Figure Description

[0021] Figure 1 The image shows the metallographic microstructure of the Mg-In-Ca-Y alloy obtained in Example 1 of this invention.

[0022] Figure 2 The images show the SEM microstructure and EDS image of the Mg-In-Ca-Y alloy obtained in Example 1 of this invention.

[0023] Figure 3 This is a half-cell test curve of the Mg-In-Ca-Y alloy obtained in Example 1 of the present invention;

[0024] Figure 4 This is a Land cell test curve of the Mg-In-Ca-Y alloy obtained in Example 1 of the present invention;

[0025] Figure 5 This is a surface SEM microstructure image of the Mg-In-Ca-Y alloy air battery obtained in Example 1 of the present invention after 6 hours of discharge.

[0026] Figure 6 This is a SEM microstructure image of the Mg-In-Ca-Y alloy air battery obtained in Example 1 of the present invention after 6 hours of discharge and removal of corrosion products.

[0027] Figure 7 The graphs show the half-cell test curves of the Mg-In-Ca-Y alloys prepared in Comparative Examples 1-5 of this invention under different current densities. Detailed Implementation

[0028] The following detailed description illustrates the specific implementation method:

[0029] To address the shortcomings of existing magnesium-air battery cathode materials, a novel Mg-In-Ca-Y alloy material is proposed. This material is prepared from high-purity Mg, In, Ca, and Y metals through smelting, solution treatment, and hot extrusion. The addition of In, Ca, and Y elements overcomes the limitations of using magnesium alloys as anode materials in magnesium-air batteries, improving their discharge activity and corrosion resistance.

[0030] The specific mass percentage composition of the Mg-In-Ca-Y alloy is as follows: Mg: 97 wt.%, In: 2 wt.%, Ca: 0.5 wt.%, Y: 0.5 wt.%; wherein the purity of Mg is greater than 99.9%, the purity of In is greater than 99.9%, the purity of Ca is greater than 99.9%, and the purity of Y is greater than 99.9%. Studies have found that the added In element can effectively accelerate the shedding of corrosion products on the surface of the magnesium alloy anode material, thereby improving its discharge activity; furthermore, the destructive effect of In on the density of the passivation film and its inhibitory effect on self-corrosion can also effectively improve the discharge performance of the magnesium alloy anode material. Ca has a higher negative standard electrode potential than Mg; after adding Ca, the discharge products generated on the electrode surface during discharge are thinner and more porous, thus improving the discharge activity of the anode material. Adding an appropriate amount of Y element can effectively help refine the grain size of the material, promote the formation of cracks in the discharge products and the shedding of the discharge products; and Y element can promote the preferential dissolution of the grain boundaries of the magnesium alloy, ensuring stable voltage during discharge.

[0031] Furthermore, due to the second phase Mg2Ca and Mg in this Mg-In-Ca-Y alloy 24 The Y5 phase exhibits refined and dispersed grains in a "waterfall" pattern, resulting in numerous uniformly distributed twins and columnar-oriented grains, which contribute to the alloy's high discharge performance. The addition of appropriate amounts of Ca significantly enhances the discharge performance of the Mg alloy, primarily due to grain refinement and the introduction of the Mg2Ca phase. Since the Mg2Ca phase has a potential approximately 50 mV more negative than the magnesium matrix, a galvanic corrosion effect occurs between the Mg2Ca phase and the magnesium matrix. The Mg2Ca phase, acting as the anode in this galvanic corrosion process, dissolves before the magnesium matrix during discharge. This reduces the adsorption force between the discharge products and the matrix, accelerates the shedding of the discharge products, and further improves the discharge performance of the magnesium alloy.

[0032] This invention also provides a method for preparing a Mg-In-Ca-Y alloy anode material for magnesium-air batteries. The Mg-In-Ca-Y quaternary magnesium alloy anode material with excellent discharge performance is prepared by melting, casting into ingots, and hot extrusion processes. The specific steps of the preparation method are as follows:

[0033] S1, smelting.

[0034] Before smelting the metal raw materials and intermediate alloy raw materials, cut the raw materials into small pieces, weigh and grind them for later use. Inspect the crucible for holes, impurities, and dryness. After confirming there are no external defects, place the crucible in a drying oven for preheating at 200℃ for 30 minutes. After preheating, remove the crucible, clean the inside, and coat the inner wall of the dry oven with a layer of boron nitride alcohol solution.

[0035] Next, the furnace temperature is raised to 720°C, and the metal raw materials and intermediate alloy raw materials are placed into the crucible in sequence. Throughout the smelting process, a protective gas mixture of CO2 and SF6 is introduced into the furnace. When adding raw materials, pure magnesium metal is added first, and other raw materials are added only after it has completely melted. Each time a raw material is added, the protective gas must be continuously introduced and the heating power must be turned off.

[0036] After confirming that all metal in the crucible has melted, the alloy melt is skimmed and stirred using a spoon coated with boron nitride alcohol solution. A protective gas must be continuously introduced during this process. After skimming, a refining agent composed of MgCl2, KCl, BaCl2, and CaF2 is added to the alloy melt until the surface of the melt is smooth like a mirror. The mass ratio of MgCl2:KCl:BaCl2:CaF2 in the refining agent is 46:42:8:5.

[0037] After holding at the temperature for another 20 minutes, the sample was removed and cooled with water to obtain an alloy ingot.

[0038] S2, solid solution.

[0039] Solution treatment was performed using a heat treatment furnace. The furnace was heated to 400°C, and the alloy ingot was placed in the furnace and held for 24 hours.

[0040] S3, hot extrusion.

[0041] The alloy ingot was extruded using an extruder. Before extrusion, the oxide scale formed on the surface of the alloy ingot was removed by sandpaper, and the alloy ingot was preheated in a 350℃ environment for 30 minutes. The temperature during the extrusion process was 350℃, and the extrusion ratio was 40:1. Finally, a block material with a thickness of 2mm was obtained, which is the Mg-In-Ca-Y alloy anode material for magnesium-air batteries.

[0042] Meanwhile, the present invention also provides a magnesium-air battery, using the Mg-In-Ca-Y alloy prepared by the above preparation method as the anode material.

[0043] To fully understand the Mg-In-Ca-Y alloy anode material for magnesium-air batteries and its preparation method, further detailed explanations will be provided below through multiple examples and comparative examples.

[0044] Example 1

[0045] Example 1 is attached. Figure 1-6 As shown, a method for preparing a Mg-In-Ca-Y alloy is included. In this embodiment, the final Mg-In-Ca-Y alloy has the following composition by mass percentage: Mg: 97 wt.%, In: 2 wt.%, Ca: 0.5 wt.%, Y: 0.5 wt.%. The specific preparation steps are as follows:

[0046] Preparation of raw materials and equipment:

[0047] Prepare the raw materials according to the required proportions. Cut the magnesium blocks, indium blocks, magnesium-calcium master alloy and magnesium-yttrium master alloy metal into small pieces, weigh and grind them for later use. See Table 1 below for details of the raw material preparation.

[0048] Table 1: Raw material quality, shape, and purity

[0049] Chemical raw materials mass / g shape purity(%) Mg 1876 block 99.99 In 40 block 99.99 Mg-20Y 50 block 99.99 Mg-30Ca 34 block 99.99

[0050] Check the new crucible for holes, impurities, and dryness. After confirming there are no external defects, place it in a drying oven for preheating at 200℃ for 30 minutes. Then, remove the crucible, clean the inside, and coat its inner wall with a boron nitride alcohol solution at a ratio of 1:4.

[0051] Next, prepare the refining agent. The specific components of the refining agent are detailed in Table 2 below.

[0052] Table 2: Refining Agent Components

[0053] Main ingredients MgCl2 KCl BaCl2 CaF2 mass percentage 46 43 8 3

[0054] Furthermore, in this embodiment, a GWJ-type vacuum induction melting furnace and a BWY-804AD(TH) type temperature controller are used to obtain the cast billet.

[0055] Alloy smelting:

[0056] 1876g of polished magnesium blocks were placed in a crucible pre-coated with boron nitride alcohol solution, and a protective gas mixture of CO2 and SF6 (volume ratio 35:1) was simultaneously introduced. When the electric furnace temperature reached 720℃, the crucible was placed in and held at that temperature for 40 minutes. After the magnesium alloy was completely molten, 40g of indium, 50g of yttrium magnesium alloy, and 34g of magnesium-calcium alloy were added sequentially, and the mixture was held at that temperature for 60 minutes to ensure sufficient diffusion of the alloying elements and homogenization of the alloy. After all the metal blocks had completely melted, oxides and impurities on the surface of the molten magnesium alloy were removed using a spoon coated with boron nitride alcohol solution.

[0057] The furnace temperature was then lowered to 700℃ for refining: 20g of refining agent was slowly added while the alloy solution was vigorously stirred with a stirring rod for 1-2 minutes.

[0058] Next, the crucible is removed and slowly placed in water to cool, resulting in an alloy ingot. Once the alloy ingot has solidified, it is removed from the water.

[0059] Solution treatment:

[0060] Heat the heat treatment furnace to 400℃, place the alloy ingot in the heat treatment furnace, and hold it at that temperature for 24 hours.

[0061] Hot extrusion treatment:

[0062] Before extrusion, the oxide scale on the surface of the alloy ingot is removed by sandpaper. It is preheated at 350℃ for 30 minutes. The extrusion temperature is set at 350℃ and the extrusion ratio is 40:1. Finally, a block material with a thickness of 2mm is obtained, which is the magnesium-air battery anode material Mg-2In-0.5Ca-0.5Y alloy.

[0063] Combination Figure 1 and Figure 2 As shown, in the Mg-2In-0.5Ca-0.5Y alloy material obtained in this embodiment, the second phase Mg2Ca and Mg... 24 The Y5 phase exhibits refined, finely dispersed grains in a "waterfall" pattern. The alloy contains numerous uniformly distributed twins and columnar-oriented grains, thus endowing the Mg-2In-0.5Ca-0.5Y alloy with high discharge performance when used in magnesium-air batteries. This is primarily due to the ability of In to regulate the morphology and distribution of the second phase in magnesium alloys, reduce the adsorption force between discharge products and the matrix, and accelerate the shedding of discharge products. Furthermore, the alloying elements Ca and Y can also refine the grains to some extent, improving electrochemical activity and further enhancing the discharge performance of the Mg-2In-0.5Ca-0.5Y alloy.

[0064] Next, a portion of the Mg-2In-0.5Ca-0.5Y alloy material prepared in this embodiment was placed in a 3.5 wt.% NaCl electrolyte for half-cell testing. The half-cell test result curve is shown in Figure 1. Figure 3 As shown, the test results are ideal. Another portion of the Mg-2In-0.5Ca-0.5Y alloy material was placed in a 3.5 wt.% NaCl electrolyte for Land cell testing. The Land cell test result curve is shown below. Figure 4 As shown: at a current density of 10 mA / cm² 2 The discharge voltage is 1.406V, and the anode utilization rate is as high as 55.3%.

[0065] Meanwhile, the performance of this Mg-2In-0.5Ca-0.5Y alloy as an anode material was further tested, such as... Figure 5 and Figure 6 As shown.

[0066] A magnesium-air battery based on Mg-2In-0.5Ca-0.5Y alloy as the anode material was tested at a current density of 2.5 mA / cm². 2 After a prolonged discharge (specifically 6 hours), the morphology of the corrosion products on the alloy surface was observed: For example... Figure 5 As shown, the surface of the alloy matrix is ​​covered by large areas of discharge products (i.e., shown in the black box in the figure), and there are many cracks on the surface of the discharge products. No uncovered blank areas are formed on the surface of the Mg-2In-0.5Ca-0.5Y alloy. This indicates that the discharge behavior of the Mg-2In-0.5Ca-0.5Y alloy is relatively uniform during the discharge process. Uniform discharge is beneficial to the entire discharge process.

[0067] After removing the corrosion products formed in the magnesium-air battery based on Mg-2In-0.5Ca-0.5Y alloy as the anode material following prolonged discharge, observation was conducted: (e.g.) Figure 6 As shown, after removing the corrosion products, the Mg-2In-0.5Ca-0.5Y alloy dissolved uniformly, and no deep pits appeared on the surface. This indicates that no large amount of unreacted matrix detached during the discharge process, further verifying that the discharge process of this alloy is stable when used as an anode material.

[0068] Example 2

[0069] The difference between Example 2 and Example 1 is that the mass of magnesium metal raw material weighed is 1910g, and the mass of Mg-30Ca intermediate alloy raw material is 0g. The final alloy material obtained is Mg-2In-0.5Y.

[0070] Example 3

[0071] The difference between Example 3 and Example 1 is that the mass of magnesium metal raw material weighed is 1926g, and the mass of Mg-20Y master alloy raw material is 0g. The final alloy material obtained is Mg-2In-0.5Ca.

[0072] Example 4

[0073] The difference between Example 4 and Example 1 is that after solution treatment, the alloy ingot is extruded using a rolling process, and the deformation during rolling is 20%. The final alloy material obtained is Mg-2In-0.5Ca-0.5Y.

[0074] Example 5

[0075] The difference between Example 5 and Example 1 is that after solution treatment, the alloy ingot is subjected to extrusion processing using a rolling process, and the deformation during rolling is 30%. The final alloy material obtained is Mg-2In-0.5Ca-0.5Y.

[0076] The magnesium alloys prepared in Examples 1-5 were used as anode materials for magnesium-air batteries, and their discharge performance was tested at different discharge current densities. The results are detailed in Tables 3 and 4 below.

[0077] Table 3: Test results of the magnesium alloy obtained in Example 1 at different discharge current densities

[0078]

[0079] Table 4: Test results of magnesium alloys obtained in Examples 1-5 at the same discharge current density

[0080]

[0081] As described above, the alloy materials obtained in all five examples exhibited excellent discharge performance. In particular, the Mg-In-Ca-Y alloy in Example 1, composed of 97 wt.% Mg, 2 wt.% In, 0.5 wt.% Ca, and 0.5 wt.% Y by mass percentage, showed even better anodic discharge efficiency. In Example 2, where Ca was omitted, the anodic discharge efficiency of the resulting Mg-2In-0.5Y alloy decreased compared to Example 1. In Example 3, where Y was omitted, the anodic discharge efficiency of the resulting Mg-2In-0.5Ca alloy decreased even more significantly compared to Example 1, indicating that omitting Y had a greater impact on the discharge efficiency of the anodic material. This further demonstrates that adding small amounts of Ca and Y to In-magnesium alloys helps improve the discharge efficiency of Mg-In-Ca-Y alloys when used as anodic materials. This is because Ca has a higher negative standard electrode potential than Mg, resulting in thinner and more porous discharge products on the electrode surface during discharge, thus enhancing anodic discharge activity. Y, on the other hand, preferentially dissolves the grain boundaries of the magnesium alloy, ensuring stable voltage during discharge. Furthermore, the introduction of Ca and Y elements leads to the appearance of a second phase in the Mg-In-Ca-Y alloy: the Mg2Ca phase and the Mg phase. 24 The Y5 phase exhibits refined, dispersed grains in a "waterfall" pattern, resulting in numerous uniformly distributed twins and columnar-oriented grains within the alloy. This structural characteristic enhances the discharge performance of the Mg alloy. Furthermore, the Mg2Ca phase has a potential approximately 50 mV more negative than the magnesium matrix, leading to galvanic corrosion between the Mg2Ca phase and the magnesium matrix. The Mg2Ca phase, acting as the anode in this galvanic corrosion process, dissolves before the magnesium matrix during discharge. This reduces the adsorption force between the discharge products and the matrix, accelerating the shedding of the discharge products and further improving the discharge performance of the Mg alloy.

[0082] As shown in Examples 1, 4, and 5, the extrusion process in preparing the Mg-In-Ca-Y alloy also significantly affects its discharge efficiency when used as an anode material. Referring to Table 4, the anode discharge efficiency of the magnesium alloy produced without hot extrusion decreased dramatically from 55.3% to 41.7% and 46.6%, respectively, indicating that plastic deformation can effectively overcome the limitations of magnesium anode materials. During the preparation process, solution treatment and hot extrusion after casting significantly refine the grain size of the magnesium alloy and alter the structure and distribution of the second phase. Hot extrusion results in a fine, dispersed second phase structure and uniform equiaxed grains, effectively suppressing hydrogen evolution self-corrosion and fast effects, promoting the shedding of discharge products, and thus significantly improving the discharge performance of the Mg-In-Ca-Y alloy.

[0083] In addition, the In element also plays an important role in this Mg-2In-0.5Ca-0.5Y alloy material, which will be further explained through the following comparative examples.

[0084] Comparative Example 1

[0085] The difference between Comparative Example 1 and Example 1 is that the raw materials are magnesium metal blocks and indium blocks, and the final anode alloy material is Mg-0.7In alloy.

[0086] Comparative Example 2

[0087] The difference between Comparative Example 2 and Example 1 is that the raw materials are magnesium metal blocks and indium blocks, and the final anode alloy material is Mg-1.4In alloy.

[0088] Comparative Example 3

[0089] The difference between Comparative Example 3 and Example 1 is that the raw materials are magnesium metal blocks and indium blocks, and the final anode alloy material is Mg-2.0In alloy.

[0090] Comparative Example 4

[0091] The difference between Comparative Example 4 and Example 1 is that the raw materials are magnesium metal blocks and indium blocks, and the final anode alloy material is Mg-2.5In alloy.

[0092] Comparative Example 5

[0093] The difference between Comparative Example 5 and Example 1 is that the raw material is only magnesium metal block, and the final anode material is pure Mg.

[0094] The anode materials obtained in Comparative Examples 1-5 were subjected to half-cell tests in electrolytes with different current densities, and the results are as follows: Figure 7 As shown. Figure 7 In Figure a, the test current density is 1 mA / cm². 2 The test current density in Figure b is 2.5 mA / cm². 2 The test current density in Figure c is 5 mA / cm². 2 The test current density in diagram d is 10 mA / cm². 2 ,

[0095] At a current density of 1 mA / cm 2 At this point, the discharge curves of both Mg-In alloy and pure Mg were relatively stable, and the Mg-2.0In alloy exhibited the most negative discharge voltage (-1.63V), indicating that the Mg-2.0In alloy had the best anodic discharge efficiency. Meanwhile, the discharge voltage of pure Mg was the most positive (-1.31V), indicating that pure Mg had the lowest anodic discharge efficiency. When the current density increased to 2.5 mA / cm², the discharge efficiency remained relatively stable. 2At this point, the discharge curves of all alloys began to fluctuate, and as the current density continued to increase, these fluctuations became more pronounced, and the curves gradually exhibited a sawtooth pattern. This sawtooth pattern arises because a dissolution reaction occurs at the anode during half-cell discharge, and as the reaction proceeds, the In produced by the anode discharge... 3+ In3+ will be deposited on the anode surface, thereby reducing the adsorption force between the corrosion products and the anode surface, increasing the effective reaction area between the anode and the electrolyte, and improving the discharge voltage. The entire discharge process is a cycle in which In3+ is continuously deposited, causing the corrosion products to peel off, resulting in a sawtooth-shaped discharge curve.

[0096] In four different current density tests, the Mg-2.0In alloy exhibited the most negative discharge voltage, indicating that it demonstrated the best anodic discharge efficiency. The anodic discharge efficiency of Mg-In alloys with contents above or below 2 wt.% decreased. In can regulate the morphology and distribution of the second phase in magnesium alloys and reduce the adsorption force between discharge products and the matrix, thereby accelerating the shedding of discharge products. In addition, controlling the In content to 2 wt.% can reduce the dendrite spacing of the alloy, thereby further improving the electrochemical activity of the magnesium alloy.

[0097] In summary, this invention addresses the problem of low discharge performance in magnesium-air battery anode materials. Using high-purity Mg, In, Ca, and Y metals as raw materials, a Mg-In-Ca-Y alloy anode material with excellent discharge performance is prepared through smelting, solution treatment, and hot extrusion. The preparation method is advanced, and the data is accurate and comprehensive. By adding trace amounts of Ca and Y elements to the Mg-In alloy, the discharge performance is improved while further controlling material costs. Solution treatment and hot extrusion significantly refine the grain size in the alloy material, altering the structure and distribution of the second phase. This grain refinement and the "waterfall-like" second phase enhance the alloy's discharge performance. Furthermore, the fine, dispersed second phase structure and uniform equiaxed grains obtained after hot extrusion effectively suppress hydrogen evolution self-corrosion and fast effects, promote the shedding of discharge products, and significantly improve the alloy's discharge performance, achieving a discharge efficiency of 10 mA / cm². 2 At current density, it achieves an excellent performance with a discharge voltage of 1.406V and an anode utilization rate of 55.3%.

[0098] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A Mg-In-Ca-Y alloy anode material for a magnesium-air battery, characterized in that, It comprises the following mass percentages: Mg: 97 wt.%, In: 2 wt.%, Ca: 0.5 wt.%, Y: 0.5 wt.%; and the Mg-In-Ca-Y alloy has a finely dispersed second phase, uniformly distributed twins, and columnar oriented grains.

2. The Mg-In-Ca-Y alloy anode material for magnesium-air batteries according to claim 1, characterized in that: The purity of Mg is greater than 99.9%, the purity of In is greater than 99.9%, the purity of Ca is greater than 99.9%, and the purity of Y is greater than 99.9%.

3. A method for preparing Mg-In-Ca-Y alloy anode material for magnesium-air batteries, characterized in that: Includes the following steps: S1, Melting: Under a protective atmosphere, magnesium blocks, pure In, Mg-20Y master alloy and Mg-30Ca master alloy are melted in sequence to obtain an alloy melt; Magnesium oxide is removed from the surface of the alloy melt, and alloy ingots are obtained through condensation treatment; S2, solution treatment: The ingot is kept at 400℃ for 24 hours; S3, Hot extrusion: Hot extrusion treatment of alloy ingots; The extrusion temperature is 350℃ and the extrusion ratio is 40:1, resulting in a 2mm thick block material, which is the Mg-In-Ca-Y alloy anode material for magnesium-air batteries.

4. The method for preparing the Mg-In-Ca-Y alloy anode material for a magnesium-air battery according to claim 3, characterized in that: In S1, the protective atmosphere uses a mixture of CO2 and SF6 as the protective gas, with a CO2:SF6 volume ratio of 35:

1.

5. The method for preparing the Mg-In-Ca-Y alloy anode material for a magnesium-air battery according to claim 4, characterized in that: In S1, the method for removing magnesium oxide from the surface of the alloy melt is as follows: under a protective gas atmosphere, a refining agent is added to the alloy melt until the surface of the alloy melt reaches a preset standard, at which point the addition is stopped.

6. The method for preparing the Mg-In-Ca-Y alloy anode material for magnesium-air electromagnets according to claim 5, characterized in that: The refining agent is a mixed solvent of MgCl2, KCl, BaCl2 and CaF2, and the mass ratio of the mixed solvent is MgCl2:KCl:BaCl:CaF2 equals 46:42:8:

5.

7. The method for preparing the Mg-In-Ca-Y alloy anode material for a magnesium-air battery according to claim 6, characterized in that: In S3, before hot extrusion of the alloy ingot, the oxides on the surface of the alloy ingot are removed by grinding, and the ground alloy ingot is preheated at 350°C for 30 minutes.

8. A magnesium-air battery, characterized in that: The Mg-In-Ca-Y alloy prepared by the preparation method described in claim 7 is used as the anode material.

Images