A method of producing a magnesium or magnesium alloy material

Abstract

The present application relates to the technical field of metal material preparation, in particular to a preparation method of magnesium or magnesium alloy material, which comprises the following steps: taking a conductive metal as a working electrode, taking magnesium or magnesium alloy as a reference electrode and a counter electrode, immersing the working electrode, the reference electrode and the counter electrode into an organic electrolyte solution containing magnesium ions, and electroplating and depositing magnesium or magnesium alloy material on the surface of the working electrode. The process flow is simple, the cost is low, and the plate-shaped magnesium or magnesium alloy material with uniform thickness can be prepared.

Description

Technical Field

[0001] This invention relates to the field of metal material preparation technology, and specifically to a method for preparing magnesium or magnesium alloy materials. Background Technology

[0002] Over the past 20 years, the research and application of magnesium and magnesium alloys have developed rapidly, especially cast magnesium alloy products, which are widely used in the automotive, military, and other fields. Rechargeable magnesium batteries, as a highly promising new type of battery, are characterized by their large theoretical volumetric capacity (3833 mAh / cm³). 3 Abundant resources (approximately 10% of lithium in the Earth's crust) 4 Magnesium alloys have attracted widespread attention due to their advantages such as high strength, low reduction potential (-2.37V), and resistance to dendrite growth. However, the development of wrought magnesium alloys has been relatively slow, especially for magnesium alloy sheets, strips, and foils produced primarily by rolling.

[0003] The processing of magnesium and magnesium alloy sheets or foils currently also employs rolling methods, and is still in the small-batch trial production stage. The thinnest thickness that can be rolled is approximately 30 micrometers, but it is difficult to roll thinner foils. This is mainly because magnesium is a close-packed hexagonal crystal, with a small number of slip systems that can be activated at room temperature. Furthermore, during rolling, it easily forms a very strong basal texture, resulting in extremely poor plasticity and formability. This leads to low deformation per rolling pass, and the rolling production process is longer than that of other metal foils such as aluminum and copper. Moreover, the yield of magnesium and magnesium alloy sheets is low, and the processing cost is high; the yield of magnesium and magnesium alloy foils is even lower, and the processing cost is extremely high.

[0004] Electrolysis is another method for producing metal foil, primarily used in the preparation of copper foil. Electrolytic copper foil is widely used in printed circuit boards and as a negative electrode current collector in lithium-ion batteries. Electrolytic magnesium is an industrial production method for primary magnesium. It involves electrolyzing molten anhydrous magnesium chloride to reduce magnesium ions at the cathode to metallic magnesium. The electrolysis temperature is around 700℃. The reduced magnesium is in a liquid state and floats on the electrolyte surface, therefore magnesium foil cannot be produced by the traditional electrolysis of molten magnesium chloride. Magnesium has a lower electrode potential than hydrogen, so magnesium foil cannot be obtained by electrolyzing magnesium ions in an aqueous solution system like copper foil. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing magnesium or magnesium alloy materials, which has a simple process, low cost, and can produce plate-shaped magnesium or magnesium alloy materials with uniform thickness.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for preparing magnesium or magnesium alloy material includes: using a conductive metal as a working electrode, using magnesium or magnesium alloy as a reference electrode and a counter electrode, immersing the working electrode, reference electrode and counter electrode in an organic electrolyte containing magnesium ions, and electroplating and depositing magnesium or magnesium alloy material on the surface of the working electrode.

[0007] Furthermore, the process parameters for electroplating deposition include: current density set to 2~100 mA / cm². 2 The temperature of the organic electrolyte containing magnesium ions is set to 0~85℃, and the electroplating deposition time is set to 0.01~10h.

[0008] Furthermore, the distance between the working electrode and the counter electrode is set to 5~15mm.

[0009] Furthermore, after the electroplating deposition is completed, the working electrode is immersed in the solvent of the organic electrolyte to remove impurities from the surface of the working electrode.

[0010] Furthermore, the working electrode, reference electrode, and counter electrode are pretreated before being immersed in an organic electrolyte containing magnesium ions. The pretreatment includes: sequentially grinding, cleaning, polishing, wiping and drying the electrodes, namely the working electrode, the reference electrode and the counter electrode, to remove impurities from the electrode surface.

[0011] Furthermore, the conductive metal includes molybdenum, titanium, stainless steel, or copper.

[0012] Furthermore, the organic electrolyte is an ether-based electrolyte or an ester-based electrolyte.

[0013] Furthermore, the reference electrode and the counter electrode are made of pure magnesium, magnesium-lithium alloy, or magnesium-gadolinium alloy.

[0014] This invention offers the following unexpected and beneficial effects: Based on the charging principle of a magnesium secondary battery and the working principle of a magnesium-copper half-cell, it uses a conductive metal as the working electrode, magnesium or a magnesium alloy as the reference electrode and counter electrode, and an organic electrolyte containing magnesium ions. During electrolysis, the magnesium or magnesium alloy at the counter electrode loses electrons and is oxidized into magnesium ions, which enter the electrolyte. These magnesium ions gain electrons at the working electrode and are reduced to magnesium, which is deposited on the surface of the working electrode. As the reduced magnesium nucleates and grows on the working electrode, magnesium or magnesium alloy material is obtained. The magnesium ion transport process in the electrolyzed magnesium or magnesium alloy material is unidirectional, moving from the counter electrode through the electrolyte to the working electrode. This invention significantly reduces the cost of magnesium or magnesium alloy preparation. During electrolysis in an organic electrolyte system, the deposition potential is less than 1 V. Calculations based on industrial practice show that the power consumption for electrolyzing magnesium or magnesium alloy is 2200 kWh / ton, achieving low-cost preparation. The preparation method is environmentally friendly, low-cost, and simple. The resulting magnesium or magnesium alloy material has a small and uniform thickness, showing great application potential. Attached Figure Description

[0015] Figure 1 These are microscopic morphology images of the magnesium foil prepared in Example 1 of this invention at different magnifications; Figure 2 This is an EDS image of the magnesium foil prepared in Example 1 of the present invention; Figure 3 These are microscopic morphology images of magnesium foils deposited at different current densities. Figure 4 These are microscopic morphology images of magnesium foils deposited at different temperatures; Figure 5 These are microscopic morphology images of magnesium foils deposited under different electrode spacings; Figure 6 These are deposition curves of working electrodes made of different materials at different current densities. Figure 7 The working electrodes are made of different materials and are sealed at a current of 2mA / cm. 2 1mAh / cm 2 Dissolution curve of the first sedimentary ring during deposition; Figure 8 These are half-cell curves for working electrodes made of different materials; Figure 9 It is a polarization curve diagram deposited on working electrodes of different materials. Detailed Implementation

[0016] The embodiments of the present invention will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are only for illustrating the present invention and not for limiting the scope of protection of the present invention.

[0017] In one embodiment, the present invention provides a method for preparing magnesium or magnesium alloy material, comprising: using a conductive metal as a working electrode, using magnesium or magnesium alloy as a reference electrode and a counter electrode, immersing the working electrode, the reference electrode and the counter electrode in an organic electrolyte containing magnesium ions, and electroplating and depositing magnesium or magnesium alloy material on the surface of the working electrode.

[0018] This invention is based on the principle of electrochemical deposition, in which magnesium ions in the electrolyte gain electrons on the surface of the working electrode (cathode) and are reduced to metal atoms under the action of an electric field, thereby depositing magnesium or magnesium alloy materials.

[0019] A conductive metal is used as the working electrode (cathode), while magnesium or a magnesium alloy serves as the reference electrode and counter electrode (anode). This configuration ensures a stable current flow during electrolysis and facilitates the reduction and deposition of magnesium ions.

[0020] Using an organic electrolyte containing magnesium ions offers higher electrochemical stability and a wider voltage window compared to traditional aqueous solutions, which facilitates electroplating deposition under milder conditions while reducing corrosion of electrode materials.

[0021] The preparation of magnesium or magnesium alloy materials specifically includes the following steps: Step 1, Electrode Preparation: Select and prepare a conductive metal as the working electrode, ensuring its surface is clean, flat, and has good conductivity. Simultaneously, prepare magnesium or a magnesium alloy as the reference electrode and counter electrode.

[0022] Step 2, electrolyte preparation: Prepare an organic electrolyte containing an appropriate amount of magnesium ions according to experimental requirements.

[0023] Step 3, Electrolytic Deposition: The working electrode, reference electrode, and counter electrode are immersed in the electrolyte, and an appropriate voltage or current is applied. Under the influence of the electric field, magnesium ions in the electrolyte migrate to the surface of the working electrode and deposit as magnesium or magnesium alloy material.

[0024] Step 4, Post-processing: After the electroplating deposition is completed, the magnesium or magnesium alloy material on the surface of the working electrode is subjected to necessary post-processing, such as cleaning, drying, and cutting, in order to obtain the desired magnesium or magnesium alloy material product.

[0025] Electrochemical deposition can directly deposit magnesium or magnesium alloy materials onto the surface of conductive metal, i.e., the working electrode, without requiring complex processing, thus improving production efficiency. Furthermore, by adjusting parameters such as the electrolyte composition and electrolysis conditions, the thickness, uniformity, and quality of the magnesium or magnesium alloy material can be precisely controlled. The prepared magnesium or magnesium alloy materials exhibit excellent conductivity, ductility, and corrosion resistance, and can be widely used in battery anode materials, electromagnetic shielding materials, packaging materials, and other fields.

[0026] In summary, the method for preparing magnesium or magnesium alloy materials provided by this invention has the advantages of simple operation, high efficiency, and strong controllability, providing new ideas and technical means for the preparation and application of magnesium or magnesium alloy materials.

[0027] In a preferred embodiment, the reference electrode and the counter electrode are pure magnesium, a magnesium-lithium alloy, or a magnesium-gadolinium alloy.

[0028] In a preferred embodiment, the process parameters for electroplating deposition include: setting the current density to 2~30 mA / cm². 2 The temperature of the organic electrolyte containing magnesium ions is set to 0~85℃, and the electroplating deposition time is set to 0.01~10h.

[0029] Current density is a key factor in controlling the deposition rate during electroplating. Lower current densities are beneficial for obtaining denser and more uniform magnesium or magnesium alloy materials, but the deposition rate is slower; higher current densities can accelerate the deposition rate, but may lead to increased surface roughness of the magnesium or magnesium alloy material, and even defects such as scorching and coarse crystals. In practice, the appropriate current density should be selected based on the required thickness and quality of the magnesium or magnesium alloy material and production efficiency. Typically, the optimal current density range needs to be determined experimentally. Preferably, the current density is set at 10 mA / cm². 2 .

[0030] Electrolyte temperature significantly affects the diffusion rate of magnesium ions, the conductivity of the electrolyte, and the kinetics of the electrode reaction. Higher temperatures can increase the conductivity of the electrolyte and the diffusion rate of magnesium ions, thereby accelerating the deposition rate; however, excessively high temperatures may lead to rapid electrolyte evaporation, decreased stability, and even side reactions. Selecting an appropriate electrolyte temperature is crucial for ensuring the stability of the electroplating process and the deposition quality. Generally, electroplating at higher temperatures yields faster deposition rates, but it is necessary to carefully control the upper temperature limit to avoid adverse consequences. Preferably, the temperature of the organic electrolyte containing magnesium ions is set at 35°C.

[0031] The electroplating deposition time directly determines the thickness of the magnesium or magnesium alloy material. A shorter deposition time may not yield a sufficiently thick magnesium or magnesium alloy material, while an excessively long deposition time may result in overly thick magnesium or magnesium alloy material, increased internal stress, or even peeling or cracking. The appropriate deposition time should be set based on the desired magnesium or magnesium alloy material thickness and electroplating efficiency. In practice, the deposition process can be monitored by periodically measuring the thickness of the magnesium or magnesium alloy material and adjusting it as needed.

[0032] In summary, setting the process parameters for electroplating deposition requires comprehensive consideration of multiple factors, including current density, electrolyte temperature, and deposition time. Optimizing these parameters can yield high-quality, uniform magnesium or magnesium alloy products. Simultaneously, it is also necessary to control other conditions during the electroplating process, such as electrolyte stirring speed, pH stability, and electrode spacing, to ensure smooth electroplating and stable, reliable deposition quality.

[0033] In a preferred embodiment, the distance between the working electrode and the counter electrode is set to 5-15 mm. When the distance between the working electrode and the counter electrode is small, the electric field strength is relatively high, which helps to accelerate the migration and reduction process of magnesium ions to the surface of the working electrode, thereby increasing the electroplating deposition rate. However, too small a distance may also lead to a decrease in the resistance of the electrolyte, causing some electrical energy to be lost as heat, thereby reducing energy efficiency. A larger distance will reduce the electric field strength, slow down the migration and reduction rate of magnesium ions, and thus reduce the electroplating deposition rate. However, appropriately increasing the distance helps to reduce the ohmic drop of the electrolyte, improve the uniformity of current distribution, and reduce coating quality problems caused by local overheating.

[0034] Appropriate spacing helps ensure a uniform distribution of the electric field on the working electrode surface, thereby promoting uniform deposition of magnesium ions and obtaining more uniform and dense magnesium or magnesium alloy materials. Too small a spacing may prevent bubbles in the electrolyte from escaping, increasing the risk of defects such as pinholes and pitting in the coating. Appropriate spacing, on the other hand, facilitates the escape of bubbles and the circulation and renewal of the electrolyte, reducing the occurrence of defects.

[0035] Therefore, when setting the spacing between the working electrode and the counter electrode, multiple factors such as electroplating efficiency, coating quality, and ease of operation need to be considered comprehensively. A spacing range of 5-15 mm is a relatively reasonable choice, but the specific value still needs to be adjusted and optimized according to the specific electroplating conditions, electrolyte formulation, and the required properties of magnesium or magnesium alloy materials. More preferably, the spacing between the working electrode and the counter electrode is set to 10 mm.

[0036] In addition, it is important to maintain the stability and consistency of the electrode spacing during the electroplating process to avoid fluctuations in plating quality caused by changes in spacing. Furthermore, attention should be paid to the cleaning and maintenance of the electrodes to ensure that their surface flatness and conductivity meet the electroplating requirements.

[0037] In a preferred embodiment, after electroplating deposition is completed, the working electrode is immersed in the solvent of an organic electrolyte to remove impurities from the surface of the working electrode.

[0038] Since the electroplating process is carried out in an organic electrolyte, it is reasonable to choose the solvent of this electrolyte as the immersion solvent. This ensures good compatibility between the solvent and the residues on the electrode surface, which is beneficial for the dissolution and removal of impurities.

[0039] During the immersion process, the solvent can penetrate and dissolve impurities adhering to the electrode surface, such as loosely deposited magnesium particles and electrolyte additive residues. If these impurities are not removed promptly, they may affect the purity, conductivity, and corrosion resistance of the magnesium or magnesium alloy material. Immersion also helps clean the electrode surface, removing defects such as bubbles and microcracks generated during electroplating, resulting in a smoother and more even surface. This is crucial for improving the uniformity and appearance quality of the magnesium or magnesium alloy material. During electroplating, the rapid deposition of magnesium ions may generate internal stress within the electrode. The immersion process helps alleviate this internal stress, reducing problems such as cracking and peeling of the magnesium or magnesium alloy material caused by excessive internal stress.

[0040] The soaking time should be determined according to the actual situation. Generally, sufficient time is needed to remove impurities, but excessive soaking time should be avoided to prevent excessive corrosion of the electrode surface or excessive solvent evaporation.

[0041] The immersion temperature can be adjusted according to the properties of the solvent and the electroplating conditions. An appropriate temperature helps to accelerate the penetration and dissolution of the solvent, improving the removal of impurities. However, excessively high temperatures may accelerate solvent evaporation and electrode corrosion, therefore careful control is necessary.

[0042] During the soaking process, the solvent can be stirred appropriately to promote the dissolution and removal of impurities. However, the stirring speed should be moderate to avoid generating excessive eddies or bubbles that could damage the electrode surface.

[0043] After soaking, the working electrode should be thoroughly cleaned and dried to remove residual solvent and moisture. Then, the magnesium or magnesium alloy material can be further processed and treated, such as cutting, rolling, and packaging, to meet different application requirements.

[0044] In summary, immersing the working electrode in an organic electrolyte solvent after electroplating deposition is a crucial step in optimizing the preparation process of magnesium or magnesium alloy materials. By employing appropriate immersion conditions and subsequent treatments, the quality and performance of magnesium or magnesium alloy materials can be significantly improved.

[0045] In a preferred embodiment, before immersing the working electrode, reference electrode, and counter electrode in an organic electrolyte containing magnesium ions, the working electrode, reference electrode, and counter electrode are pretreated; the pretreatment includes: sequentially grinding, cleaning, polishing, wiping, and drying the electrodes, i.e., the working electrode, reference electrode, and counter electrode, to remove impurities from the electrode surface.

[0046] The main purpose of pretreatment is to remove impurities, oxide layers, oil stains, etc. that may exist on the electrode surface, so as to improve the conductivity, flatness and surface activity of the electrode, thereby facilitating the uniform deposition of magnesium ions and the tight adhesion of the coating.

[0047] Grinding: Use appropriate sandpaper or grinding tools to grind the electrode surface to remove rough areas, scratches, and larger impurity particles. During grinding, be careful to apply even pressure and avoid excessive wear on the electrode substrate.

[0048] Cleaning: Immerse the polished electrodes in a cleaning solution (such as deionized water, dilute acid solution, or organic solvent) to remove surface dust, oil, and other impurities through soaking, rinsing, or ultrasonic cleaning. The choice of cleaning solution should be determined based on the electrode material and the nature of the surface contaminants.

[0049] Polishing: Use polishing compound or polishing cloth to polish the electrode surface to further smooth the surface and remove minor scratches and unevenness generated during the grinding process. After polishing, the electrode surface should have a bright, mirror-like finish.

[0050] Cleaning: Use a clean, soft material such as a cotton cloth or lint-free paper to clean the electrode surface to remove any polishing paste, stains, or other residues that may have remained from the polishing process. Be careful not to apply excessive force during cleaning to avoid scratching the electrode surface.

[0051] Drying: Place the cleaned electrodes in a desiccator or use hot air to dry them, ensuring that no moisture remains on the electrode surface. Avoid high-temperature baking during the drying process to prevent deformation or damage to the electrode material.

[0052] Pretreatment to remove oxide layers and impurities from the electrode surface can improve electrode conductivity and reduce resistance loss during electroplating. Furthermore, a smooth, clean electrode surface facilitates uniform deposition of magnesium ions and tight adhesion of the plating layer, reducing the risk of peeling or cracking. Simultaneously, pretreatment removes microscopic defects and impurity particles from the electrode surface, thereby reducing the defect and impurity content in the plating layer and improving its uniformity, density, and corrosion resistance.

[0053] In summary, pretreatment of the working electrode, reference electrode, and counter electrode is an indispensable and crucial step before electroplating deposition. By implementing a reasonable pretreatment process and controlling the conditions, ensuring the cleanliness and smoothness of the electrode surfaces meet the electroplating requirements lays a solid foundation for obtaining high-quality magnesium or magnesium alloy materials.

[0054] In a preferred embodiment, the conductive metal includes molybdenum, stainless steel, or copper.

[0055] Molybdenum (Mo) is a high-melting-point, high-hardness metal with good electrical conductivity and corrosion resistance. Its stability is particularly outstanding at high temperatures. Due to these properties, molybdenum is frequently used in the manufacture of electrode materials, especially in applications requiring operation in high-temperature or highly corrosive environments.

[0056] Stainless steel (SS) is an alloy steel mainly composed of elements such as iron, chromium, and nickel. It possesses excellent corrosion resistance and good mechanical properties. Stainless steel also exhibits a certain degree of electrical conductivity. It is widely used in various fields, including as an electrode material in electrochemical deposition processes. Its corrosion resistance allows stainless steel electrodes to remain stable in a variety of electrolytes.

[0057] Copper (Cu) is a metal with excellent electrical conductivity, second only to silver. Furthermore, copper has good ductility and malleability, making it easy to process into various shapes. Copper is one of the commonly used electrode materials in the electroplating industry because it can efficiently conduct current and is relatively inexpensive.

[0058] The choice of conductive metal should be determined based on specific application requirements. Molybdenum, stainless steel, and copper are all excellent choices for conductive metals, each with its own unique advantages and applicable range.

[0059] In a preferred embodiment, the organic electrolyte is an ether-based electrolyte or an ester-based electrolyte. Ether-based electrolytes generally have good solubility and stability, can dissolve a variety of electrolyte salts, and remain stable over a wide voltage range. Ester-based electrolytes generally have high flash points and low volatility, meaning they are relatively safe during use. Ester-based electrolytes also possess certain solubility and stability. The choice of organic electrolyte should be determined based on the specific electrochemical process and requirements. Both ether-based and ester-based electrolytes have their advantages and can exhibit excellent performance under suitable conditions.

[0060] For example, the organic electrolyte is APC electrolyte, Mg(TFSI)2-based electrolyte, MDGM electrolyte or MTC electrolyte.

[0061] The preparation of APC electrolyte involves dissolving phenyl magnesium chloride and aluminum chloride in tetrahydrofuran to obtain the APC electrolyte.

[0062] The preparation of Mg(TFSI)2-based electrolyte involves: first, adding 0.4515 g of 1-methoxy-2-propylamine (Sigma-Aldrich, 99%) to 2 mL of DME (Sigma-Aldrich, anhydrous, 99.5%, inhibitor-free), and then adding Mg(TFSI)2 (Duoduo reagent, 99.5%) while stirring. The final solution is not completely clear but is semi-transparent.

[0063] The preparation of MDGM electrolyte involves mixing 10 mL of DME, 10 mL of diethylene glycol dimethyl ether, 4.14 mL of MOEA, and 3.2245 g of magnesium trifluoromethanesulfonate until homogeneous.

[0064] The preparation of MTC electrolyte involves: first, adding 0.5846 g of MgCl2 (thermofisher, ultra-dry, 99.99%) to 2 mL of DME (Sigma-Aldrich, anhydrous, 99.5%, inhibitor-free / macklin 99.5%, with molecular sieves) while stirring. The stirring speed is set to 200-300 rpm. After stirring for 3-15 minutes, add 0.1904 g of Mg(TFSI)2 (Duoduo reagent, 99.5%) while stirring. Then, adjust the stirring speed to 500-600 rpm. The solution becomes clear and transparent overnight, which is the MTC electrolyte.

[0065] The following analysis and explanation will be provided with specific examples.

[0066] Example 1: A low-cost method for preparing magnesium foil, comprising the following steps: Step 1: Cut the purchased high-purity magnesium and molybdenum sheets with a thickness of 0.2mm into rectangular sheets with a size of 15mm × 10mm.

[0067] Step two: Perform surface treatment on the cut magnesium and molybdenum sheets. Select 400-grit, 600-grit, 1000-grit, 1200-grit, 1500-grit, and 2000-grit sandpaper in sequence to polish them. Then, clean them with acetone and deionized water to remove impurities from the entire electrode surface. Next, polish them with Al2O3 powder, wipe them with alcohol again, ultrasonically clean them for 10 minutes, dry them in a vacuum drying oven for 12 hours, and then put them in a glove box for later use.

[0068] Step 3: Correctly assemble the electrodes. The working electrode is a molybdenum sheet, and the reference and counter electrodes are both magnesium sheets. Adjust the electrode spacing to 5 mm, inject 4 mL of APC electrolyte, and adjust the current density to 10 mA / cm² at room temperature (25°C). 2 After about 40 minutes of deposition, a magnesium foil with a thickness of about 17 μm was deposited on the surface of the working electrode.

[0069] Step four: After deposition is complete, remove the working electrode and soak it in a pure electrolyte solvent for 12 hours to remove impurities.

[0070] The microstructure of the magnesium foil prepared in this example was observed, and the results are shown in [reference]. Figure 1 The SEM images show that magnesium is deposited relatively uniformly on the molybdenum working electrode, with densely packed particles of almost the same size.

[0071] The magnesium foil prepared in this example was subjected to EDS analysis, and the results are shown in [reference needed]. Figure 2 The red area in the EDS spectrum is magnesium, and the black area is because there is no part of the oxidation process that was carried out in the vacuum transfer. The distribution of magnesium is uniform.

[0072] Example 2: Adjusting different current densities to compare the deposition uniformity, controlling the current density at 2, 3, 4, 5, 6, 7, 8, and 9 mA / cm². 2 The deposition process continues, with the remaining steps being the same as in Example 1.

[0073] The microstructure of the magnesium foil deposited at the corresponding current density is shown in the figure. Figure 3 As shown, with the increase of current density, polarization increases and the deposition becomes more uniform. From the actual SEM images, it can be seen that the particle radius of magnesium deposition is decreasing, and the packing is dense and uniform. The deposition is most uniform at 10 mA / cm².

[0074] Example 3: The uniformity of deposition was compared by adjusting different temperatures. Deposition was carried out at electrolyte temperatures of 35°C, 45°C, 55°C, 65°C, and 75°C. The remaining steps were the same as in Example 1.

[0075] The microstructure of magnesium foils deposited at different temperatures was observed; the results are shown in [reference needed]. Figure 4 As shown, polarization decreases with increasing temperature, theoretically leading to an increase in deposited particles. However, at 35℃, the particles are relatively uniform. Furthermore, increasing the temperature can simultaneously increase the current density, thus improving deposition efficiency by both decreasing and increasing polarization. Excessively high temperatures can cause electrolyte decomposition, resulting in a less dense coating and poor adhesion to the substrate.

[0076] Example 4: Adjusting different electrode spacings to compare the uniformity of deposition. Deposition was carried out with electrode spacing of 5 mm and 10 mm, and the remaining steps were the same as in Example 1.

[0077] The microstructure of magnesium foils deposited under different electrode spacings was observed. See the results below. Figure 5 As shown, the electric field distribution becomes more uniform with increasing electrode spacing. At smaller electrode spacings, the electric field becomes excessively large locally, leading to preferential deposition and growth in certain areas, resulting in poor deposition quality. Conversely, excessively large electrode spacings reduce concentration polarization, increase migration paths, and also cause larger deposited particles. The deposition layer is most uniform at a 10 mm electrode spacing, and SEM and EDS images show that Mg is deposited particularly uniformly on the working electrode.

[0078] Example 5: Adjusting the effect of different working electrode materials on the preparation of magnesium foil, depositing on stainless steel (SS), Cu (copper), and Ti (titanium), with the remaining steps being the same as in Example 1.

[0079] Figure 6 The discharge curves for deposition at different current densities show that Mo has the lowest nucleation overpotential and deposition over-site, which is more conducive to deposition. It can also be seen that polarization increases with increasing current density.

[0080] Figure 7 The first-cycle deposition and dissolution curves at 1 mAh / cm² and 2 mA / cm² show that Mg has the highest coulombic efficiency on Mo, which indirectly explains the strongest affinity of Mo for magnesium.

[0081] Figure 8 The CV curves for several half-cells show that when the reduction reaction occurs on Mo, the potential shifts to the negative direction, indicating that the reaction is more likely to occur.

[0082] Figure 9The figures show polarization curves deposited on several metals. A larger slope indicates greater polarization. Based on the analysis of experimental data, the Tafel slope deposited on Mo is larger, indicating that the deposition process on Mo is more uniform when different process conditions are controlled.

[0083] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention.

Claims

1. A method for preparing magnesium or magnesium alloy materials, characterized in that, include: A conductive metal is used as the working electrode, including molybdenum, titanium, stainless steel, or copper. Pure magnesium, magnesium-lithium alloy, or magnesium-gadolinium alloy is used as the reference electrode and counter electrode. The working electrode, reference electrode, and counter electrode are immersed in an organic electrolyte containing magnesium ions. The distance between the working electrode and the counter electrode is set to 5-15 mm. Magnesium or magnesium alloy material is electroplated and deposited on the surface of the working electrode. The magnesium or magnesium alloy material is a foil or a thin plate. The organic electrolyte is APC electrolyte, Mg(TFSI)2-based electrolyte, MDGM electrolyte or MTC electrolyte; The preparation of APC electrolyte involves dissolving phenyl magnesium chloride and aluminum chloride in tetrahydrofuran to obtain APC electrolyte. The preparation of Mg(TFSI)2-based electrolyte involves: first adding 0.4515 g of 1-methoxy-2-propylamine to 2 mL of DME, and then adding Mg(TFSI)2 while stirring. The final solution is not completely clear and is semi-transparent. The preparation of MDGM electrolyte involves mixing 10 mL of DME, 10 mL of diethylene glycol dimethyl ether, 4.14 mL of MOEA and 3.2245 g of magnesium trifluoromethanesulfonate until homogeneous to obtain MDGM electrolyte. The preparation of MTC electrolyte involves: first, adding 0.5846g of MgCl2 to 2mL of DME while stirring, setting the stirring speed to 200~300rpm, and stirring for 3~15min. Then, adding 0.1904g of Mg(TFSI)2 while stirring, and then adjusting the stirring speed to 500~600rpm. The solution becomes clear and transparent overnight, which is the MTC electrolyte.

2. The method for preparing magnesium or magnesium alloy materials according to claim 1, characterized in that, The process parameters for electroplating deposition include: current density set to 2~100 mA / cm². 2 The temperature of the organic electrolyte containing magnesium ions is set to 0~85℃, and the electroplating deposition time is set to 0.01~10h.

3. The method for preparing magnesium or magnesium alloy materials according to claim 1, characterized in that: After electroplating deposition is completed, the working electrode is immersed in the solvent of organic electrolyte to remove impurities from the surface of the working electrode.

4. The method for preparing magnesium or magnesium alloy materials according to claim 1, characterized in that: Before immersing the working electrode, reference electrode, and counter electrode in an organic electrolyte containing magnesium ions, the working electrode, reference electrode, and counter electrode are pretreated. The pretreatment includes: sequentially grinding, cleaning, polishing, wiping and drying the electrodes, namely the working electrode, the reference electrode and the counter electrode, to remove impurities from the electrode surface.

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