Magnesium-air battery, magnesium-air fiber battery and preparation method thereof

Abstract

The invention relates to a magnesium air battery, a magnesium air fiber battery and a preparation method thereof, and the preparation method comprises the following steps: dissolving bis (trifluoromethylsulfonyl) imide magnesium and chlorate in a solvent, then adding a molecular sieve, drying to remove water, and separating the molecular sieve to obtain an electrolyte; adding N-methyl pyrrolidone and poly (vinylidene fluoride-co-hexafluoropropylene) into the electrolyte, adding trimethylolpropane triacrylate as a cross-linking agent, and adding a 2-hydroxy-2-methyl-1-phenyl-1-acetone reagent as an initiator in the stirring process to obtain a polymer gel electrolyte precursor; coating the polymer gel electrolyte precursor on a glass fiber diaphragm, performing ultraviolet curing, and then assembling the polymer gel electrolyte precursor, a magnesium anode strip and a carbon nanotube film cathode to obtain the magnesium air battery. Or coating a magnesium wire with the polymer gel electrolyte precursor, carrying out ultraviolet curing, and then assembling with a carbon nanotube film cathode to obtain the magnesium air fiber battery. The anode corrosion induced by moisture is effectively inhibited in the air, and the charge-discharge reversibility is remarkably improved.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical technology, specifically relating to a magnesium-air battery, a magnesium-air fiber battery, and a method for preparing the same. Background Technology

[0002] Magnesium-air batteries (MABs) have garnered significant attention due to their high theoretical energy density, cost-effectiveness, and inherent safety. Furthermore, their simple structure and ease of manufacturing have enabled the development of one-dimensional fiber structures, such as fiber magnesium-air batteries (FMABs), offering enhanced flexibility and superior compatibility with wearable electronic devices.

[0003] Magnesium metal possesses a low reduction potential (-2.37 V vs. SHE) and a high specific capacity (2205 mAh·g). -1 Magnesium, with its abundant reserves, is a potential alternative to lithium-ion batteries. However, traditional magnesium batteries (with intercalated cathodes) have limited capacity, making it difficult to fully utilize the advantages of magnesium metal; magnesium-air batteries have high theoretical energy density, but poor reversibility in ambient air: the MgO generated during discharge... x It is difficult to decompose during charging, gradually clogging the active sites of the air electrode; at the same time, ambient moisture penetrates the electrolyte and corrodes the magnesium anode, leading to rapid performance degradation. Therefore, most studies have turned to testing in pure oxygen (actually Mg-O2 batteries), which is inconsistent with real application scenarios. Summary of the Invention

[0004] Based on the aforementioned shortcomings and deficiencies in the prior art, one of the objectives of this invention is to at least solve one or more of the aforementioned problems in the prior art. In other words, one of the objectives of this invention is to provide a magnesium-air battery, a magnesium-air fiber battery, and a method for preparing the same that meets one or more of the aforementioned requirements. By utilizing a polymer gel electrolyte to effectively protect the magnesium anode, the reversibility of the reaction and cycle life are significantly improved, achieving at least 160 stable cycles in an air environment. Furthermore, it can be fabricated into a fibrous form and integrated into fabrics and photovoltaic systems, thus possessing practical application potential.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: A method for preparing a magnesium-air battery includes the following steps: (1) Dissolve magnesium bis(trifluoromethanesulfonyl)imide and chloride in a solvent, then add molecular sieve to dry and remove water, and obtain electrolyte after separation by molecular sieve; (2) Add N-methylpyrrolidone and poly(vinylidene fluoride-) to the electrolyte. co (-hexafluoropropylene), and added trimethylolpropane triacrylate as a crosslinking agent, and 2-hydroxy-2-methyl-1-phenyl-1-propanone reagent as an initiator during stirring to obtain a polymer gel electrolyte precursor; (3) The polymer gel electrolyte precursor is coated on the glass fiber membrane and cured by ultraviolet light. Then it is assembled with magnesium anode sheet and carbon nanotube thin film cathode to obtain magnesium air battery.

[0006] This invention also provides a method for preparing a magnesium-air fiber battery, comprising the following steps: (1) Dissolve magnesium bis(trifluoromethanesulfonyl)imide and chloride in a solvent, then add molecular sieve to dry and remove water, and obtain electrolyte after separation by molecular sieve; (2) Add N-methylpyrrolidone and poly(vinylidene fluoride-) to the electrolyte. co (-hexafluoropropylene), and added trimethylolpropane triacrylate as a crosslinking agent, and 2-hydroxy-2-methyl-1-phenyl-1-propanone reagent as an initiator during stirring to obtain a polymer gel electrolyte precursor; (3) The polymer gel electrolyte precursor was coated on magnesium wire and cured with ultraviolet light, and then assembled with carbon nanotube thin film cathode to obtain magnesium air fiber battery.

[0007] As a preferred embodiment, the molar ratio of the chloride salt to magnesium bis(trifluoromethylsulfonyl)imide is (1-5):1.

[0008] As a preferred embodiment, the chloride salt is magnesium chloride, potassium chloride, sodium chloride, calcium chloride, or copper chloride.

[0009] As a preferred embodiment, the solvent is ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, or tetraethylene glycol dimethyl ether.

[0010] As a preferred embodiment, in step (2), the electrolyte, trimethylolpropane triacrylate, N-methylpyrrolidone, and poly(vinylidene fluoride) are used. co The mass ratio of the reagents 2-hexafluoropropylene and 2-hydroxy-2-methyl-1-phenyl-1-propanone is 4:4:4:(1-3):(0.01-0.1).

[0011] As a preferred embodiment, in step (3), the surface of the magnesium anode sheet or magnesium wire is first sanded to remove the surface oxide film.

[0012] As a preferred embodiment, in step (3), the carbon nanotube thin film cathode is first soaked in nitric acid to remove impurities.

[0013] As a preferred embodiment, in step (3), the UV curing time is 5 to 10 seconds.

[0014] The present invention also provides a magnesium-air battery prepared by the preparation method described in any of the preceding embodiments, wherein the magnesium-air battery has a cycle life of not less than 100 cycles.

[0015] The present invention also provides a magnesium-air fiber battery prepared by the preparation method described in any of the preceding embodiments, wherein the magnesium-air fiber battery has a cycle life of not less than 100 cycles.

[0016] Compared with the prior art, the beneficial effects of this invention are: The magnesium-air battery and magnesium-air fiber battery of the present invention have air resistance and corrosion resistance. The polymer gel electrolyte has a room temperature conductivity of 4.4 mS·cm⁻¹ and an anode stability of up to 5 V, significantly reducing magnesium corrosion (3.62 × 10⁻¹). 5 (A·cm⁻²; 0.058mg·cm⁻¹·h⁻¹); Long cycle life: achieving 160 stable cycles in ambient air, with a discharge of approximately 1.42 V and a capacity of approximately 500 mAh·g⁻¹. Furthermore, the polymer gel electrolyte can be used to fabricate one-dimensional magnesium-air fiber batteries, exhibiting a voltage curve that remains essentially unchanged under bending / torsion. It can be used in series for fabric LED displays or integrated with photovoltaic blankets as a mobile phone charging system, showing broad application prospects in the next generation of wearable energy storage. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the preparation of the polymer gel electrolyte in Example 1 of the present invention; Figure 2 This is a scanning electron microscope image of the polymer gel electrolyte of Example 1 of the present invention; Figure 3 This is a comparison diagram of the polarization curves of the polymer gel electrolyte coated on and uncoated magnesium electrode in Example 1 of the present invention; Figure 4 This is a comparison chart of the corrosion rates of the polymer gel electrolyte coated on and uncoated magnesium electrodes in Example 1 of the present invention. Figure 5 This is a comparison diagram of symmetrical battery electroplating / stripping cycles of polymer gel electrolyte and liquid electrolyte in Example 1 of the present invention; Figure 6 This is a schematic diagram of the assembly of the magnesium-air battery according to Embodiment 1 of the present invention; Figure 7 This is a cycle performance diagram of a magnesium-air battery assembled with a polymer gel electrolyte according to Example 1 of the present invention; Figure 8 This is a schematic diagram of the assembly of the magnesium-air fiber battery according to Embodiment 1 of the present invention; Figure 9 This is a cycle performance diagram of the polymer gel electrolyte assembled into a magnesium-air battery according to Example 6 of the present invention; Figure 10 This is a cycle performance diagram of the polymer gel electrolyte assembled into a magnesium-air battery according to Example 7 of the present invention; Figure 11This is a cycle performance diagram of the polymer gel electrolyte (without magnesium chloride) assembled into a magnesium-air battery according to Comparative Example 1 of the present invention. Figure 12 This is a cycle performance diagram of a magnesium-air battery assembled with the liquid electrolyte of Comparative Example 2 of the present invention; Figure 13 This is a graph showing the cycle performance of the magnesium-air battery of Comparative Example 3 of the present invention in a dry air environment. Figure 14 This is a schematic diagram of the novel cathodic chemical mechanism of the present invention. Detailed Implementation

[0018] The magnesium-air battery, magnesium-air fiber battery and their preparation method of the present invention will be described in detail below.

[0019] The method for preparing a magnesium-air battery or magnesium-air fiber battery of the present invention includes the following steps: (1) Dissolve magnesium bis(trifluoromethanesulfonyl)imide and chloride in a solvent, then add molecular sieve to dry and remove water, and obtain electrolyte after separation by molecular sieve; The molar ratio of chloride salt to magnesium bis(trifluoromethylsulfonyl)imide is (1-5):1, and the specific molar ratio can be determined according to the actual application requirements. The above-mentioned chloride salts are magnesium chloride, potassium chloride, sodium chloride, calcium chloride, or copper chloride, and the specific choice can be made according to the actual application requirements. The solvents mentioned above are ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, or tetraethylene glycol dimethyl ether, and the specific choice can be made according to the actual application requirements.

[0020] (2) Add N-methylpyrrolidone and poly(vinylidene fluoride-) to the electrolyte. co (-hexafluoropropylene), and added trimethylolpropane triacrylate as a crosslinking agent, and 2-hydroxy-2-methyl-1-phenyl-1-propanone reagent as an initiator during stirring to obtain a polymer gel electrolyte precursor; Among them, the electrolyte, trimethylolpropane triacrylate, N-methylpyrrolidone, and poly(vinylidene fluoride) co The mass ratio of hexafluoropropylene and 2-hydroxy-2-methyl-1-phenyl-1-propanone reagents is 4:4:4:(1~3):(0.01~0.1), and the specific mass ratio can be determined according to the actual application requirements.

[0021] (3) The polymer gel electrolyte precursor is coated on the glass fiber membrane and cured by ultraviolet light. Then it is assembled with magnesium anode sheet and carbon nanotube thin film cathode to obtain magnesium air battery. Alternatively, a polymer gel electrolyte precursor can be coated onto a magnesium wire and cured with ultraviolet light, and then assembled with a carbon nanotube thin film cathode to obtain a magnesium-air fiber battery.

[0022] In this process, the magnesium anode sheet or magnesium wire is first sanded to remove the surface oxide film; the carbon nanotube thin film cathode is first soaked in nitric acid to remove impurities. The magnesium sheets or magnesium wires and carbon nanotube thin film cathodes in subsequent embodiments and comparative examples are all after treatment, and will not be described further.

[0023] The UV curing time is 5-10 seconds, and the specific time can be determined according to the actual curing situation.

[0024] The present invention also provides a magnesium-air battery prepared based on the above preparation method.

[0025] If magnesium wire is chosen as the magnesium anode, then the magnesium-air battery is a magnesium-air fiber battery, which can be made into a fiber and integrated into fabrics and photovoltaic systems, and has practical application potential.

[0026] The magnesium-air battery and its preparation method of the present invention will be further explained and illustrated below through examples and comparative examples.

[0027] Example 1: The preparation method of the magnesium-air battery in this experimental example includes the following steps: (1) such as Figure 1 As shown, in an argon-filled glove box, 0.11 g of magnesium bis(trifluoromethanesulfonyl)imide and 0.036 g of magnesium chloride were added to a 0.654 g solution of ethylene glycol dimethyl ether in a 10 mL glass bottle. The solution was then transferred to a stirrer and stirred until completely dissolved. Molecular sieves were added, and the solution was dried overnight to obtain a liquid electrolyte. (2) Take 0.4 g of liquid electrolyte, add 0.4 g of N-methylpyrrolidone and 0.1 g of poly(vinylidene fluoride-) co -hexafluoropropylene), and add 0.4 g of trimethylolpropane triacrylate as a crosslinking agent. Transfer the glass bottle to a stirrer, and while stirring, add 0.04 g of 2-hydroxy-2-methyl-1-phenyl-1-propanone reagent as an initiator to obtain the polymer gel electrolyte precursor; like Figure 2 The image shown is a scanning electron microscope (SEM) image of the polymer gel electrolyte, revealing its uniform and dense structure. Figure 3 and Figure 4 The figures show a comparison of polarization curves and corrosion rates for the polymer gel electrolyte coated on a magnesium electrode (i.e., the polymer gel electrolyte precursor is coated on the magnesium electrode and then cured under UV light for 10 seconds) versus the uncoated electrode. This confirms the protective effect of the gel. The corrosion current density and corrosion rate of the gel-coated magnesium electrode are 3.62 × 10⁻⁻⁻⁶, respectively. 5The A·cm⁻² and 0.058 mg·cm⁻¹·h⁻¹ values ​​were almost 30 times lower than those of the uncoated sample. The symmetric cell plating / stripping cycles of the aforementioned polymer gel electrolyte and liquid electrolyte were compared, for example... Figure 5 As shown, batteries containing liquid electrolytes degrade rapidly, failing within 350 stripping / coating cycles. In contrast, batteries using polymer gel electrolytes maintained stable operation with minimal voltage fluctuations for over 1000 cycles.

[0028] (3) The polymer gel electrolyte precursor was coated onto a 16 mm diameter glass fiber membrane and cured under 365 nm ultraviolet light for 10 s to obtain the glass fiber membrane and the polymer gel electrolyte attached thereon; then, in an argon-filled glove box, as shown... Figure 6 As shown, first, the negative electrode base of the coin cell and the stainless steel sheet are placed. Then, the magnesium sheet, glass fiber separator and its attached polymer gel electrolyte, carbon nanotube film, conductive nickel sheet, and stainless steel spring are sequentially placed into the CR2032 coin cell. Finally, the porous cathode shell is placed, and the battery assembly is completed, resulting in a magnesium-air battery. Its cycle performance is as follows: Figure 7 As shown, it can achieve a long cycle life of 160 cycles in air, with the first cycle accompanied by a high discharge voltage of 1.42 V.

[0029] Alternatively, the preparation method of the magnesium-air fiber battery in this embodiment includes: uniformly coating a gel electrolyte precursor solution onto the surface of a magnesium wire using a dip-coating method, followed by irradiation with 365 nm ultraviolet light for 10 seconds to initiate gel formation. This process is repeated at least three times to ensure that the surface of the magnesium wire is completely and uniformly covered. After the gel layer is formed, a carbon nanotube cathode is carefully wrapped around the outside of the magnesium wire coated with the gel layer to serve as the cathode of the battery. Finally, the fiber-shaped battery is encapsulated and protected using a perforated heat-shrink tubing. Figure 8 As shown.

[0030] Example 2: The difference between the preparation method of the magnesium-air battery in this embodiment and that in Example 1 is: The weight of magnesium bis(trifluoromethanesulfonyl)imide is 0.22 g, so that the molar ratio of magnesium chloride to magnesium bis(trifluoromethanesulfonyl)imide is 1:1; The other steps are the same as in Example 1.

[0031] Example 3: The difference between the preparation method of the magnesium-air battery in this embodiment and that in Example 1 is: Adjust the weight of magnesium chloride to make the molar ratio of magnesium chloride to magnesium bis(trifluoromethanesulfonyl)imide 3:1; The other steps are the same as in Example 1.

[0032] Example 4: The difference between the preparation method of the magnesium-air battery in this embodiment and that in Example 1 is: Adjust the weight of magnesium chloride to make the molar ratio of magnesium chloride to magnesium bis(trifluoromethanesulfonyl)imide 4:1; The other steps are the same as in Example 1.

[0033] Example 5: The difference between the preparation method of the magnesium-air battery in this embodiment and that in Example 1 is: Adjust the weight of magnesium chloride to make the molar ratio of magnesium chloride to magnesium bis(trifluoromethanesulfonyl)imide 5:1; The other steps are the same as in Example 1.

[0034] Example 6: The difference between the preparation method of the magnesium-air battery in this embodiment and that in Example 1 is: In the preparation of the liquid electrolyte, the solvent ethylene glycol dimethyl ether solution is replaced with diethylene glycol dimethyl ether solution; The other steps are the same as in Example 1.

[0035] like Figure 9 As shown, the magnesium-air battery of this embodiment has the following cycle performance: it can achieve a long cycle life of 101 cycles in air, and the first cycle is accompanied by a high discharge voltage of 1.32 V.

[0036] Example 7: The difference between the preparation method of the magnesium-air battery in this embodiment and that in Example 1 is: In the preparation of the liquid electrolyte, the solvent ethylene glycol dimethyl ether solution is replaced with tetraethylene glycol dimethyl ether solution; The other steps are the same as in Example 1.

[0037] like Figure 10 As shown, the magnesium-air battery of this embodiment has the following cycle performance: it can achieve a long cycle life of 140 cycles in air, and the first cycle is accompanied by a high discharge voltage of 1.23 V.

[0038] Comparative Example 1: The preparation method of the magnesium-air battery in this comparative example differs from that in Example 1 in that: No magnesium chloride was added; the other steps were the same as in Example 1.

[0039] like Figure 11 As shown, the magnesium-air battery in this comparative example has the following cycle performance: it can only achieve a cycle life of 5 cycles in air, and the first cycle is accompanied by a discharge voltage of only 0.45 V.

[0040] Comparative Example 2: The preparation method of the magnesium-air battery in this comparative example differs from that in Example 1 in that: The liquid electrolyte from Example 1 was used directly as the electrolyte, i.e., the liquid electrolyte was directly dropped onto the glass fiber membrane; no polymer gel electrolyte was formed. The other steps are the same as in Example 1.

[0041] like Figure 12 As shown, the magnesium-air battery in this comparative example has the following cycle performance: it can only achieve a cycle life of 46 cycles in air, and the first cycle is accompanied by a discharge voltage of only 0.85 V.

[0042] Comparative Example 3: The difference between the cycle performance of the magnesium-air battery in this comparative example and that in Example 1 is: The test was conducted in a dry air environment, and other procedures were the same as in Example 1. like Figure 13 As shown, its cycle performance is as follows: it can only discharge and not charge in dry air, and the first cycle is only accompanied by a discharge voltage of 0.94 V. This is because without the participation of moisture, chloride ions in the electrolyte cannot work synergistically, and the cathode product is magnesium peroxide (MgO2). Magnesium peroxide is formed by the combination of Mg²⁺ and peroxide ions (O2²⁻) through ionic bonds, which is difficult to decompose. During discharge, magnesium peroxide products accumulate on the carbon nanotube cathode, but they are difficult to decompose during charging, causing the charging voltage to quickly reach the cutoff voltage of 5 V, and the battery cycle stops.

[0043] Table 1. Comparison of energy efficiency and cycle performance of the examples, comparative examples, and references. ; As shown in Table 1, regarding electrolyte selection, the highest cycle performance of magnesium-air batteries reported in the literature does not exceed 115 cycles, and the discharge voltage does not exceed 1.25 V, which is far lower than that of the magnesium-oxygen battery constructed from polymer gel electrolyte in Example 1. Furthermore, this invention demonstrates that atmospheric moisture can synergistically interact with chloride ions in the electrolyte, regulating the cathode reaction pathway and thereby generating magnesium oxychloride (Mg3(OH)5Cl・4H2O) as a discharge product. This invention establishes a novel cathode chemical mechanism, such as... Figure 14 As shown, the reaction equation is 12Mg²⁺ + 4Cl⁻ + 5O₂ + 26H₂O → 4Mg₃(OH)₅Cl・4H₂O, which is different from the traditional MgO. xThe reaction pathway and mechanism significantly improve the reversibility of the redox reaction. Simultaneously, the waterproof polymer gel electrolyte of this invention provides a robust protective layer for the magnesium anode, effectively mitigating corrosion problems caused by moisture. Therefore, the magnesium-air battery of this invention achieves more than 160 stable cycles under ambient air conditions, with a discharge voltage as high as 1.42 V and a discharge capacity of 500 mAh·g⁻¹, significantly superior to existing magnesium-air battery systems.

[0044] This invention relates to a highly reversible magnesium-air battery that operates stably in ambient air for extended periods. Using magnesium as the anode and a carbon nanotube (CNT) film as the air cathode, coupled with a waterproof polymer gel electrolyte (PVDF-HFP matrix, TMPTA crosslinking, Mg(TFSI)2 / MgCl2 salt, DME / NMP solvent, HMPP photoinitiation, 365 nm UV curing), it effectively inhibits moisture-induced anodic corrosion in air. Furthermore, it reveals for the first time that atmospheric humidity participates in the cathode reaction to generate reversible discharge products of magnesium oxychloride (Mg3(OH)5Cl·4H2O), significantly improving charge-discharge reversibility. The battery achieves stable cycling for over 160 cycles in ambient air, with a discharge voltage of approximately 1.42 V and a discharge capacity of 500 mAh·g⁻¹; the gel electrolyte imparts a system efficiency of 4.4 mS·cm⁻¹. -1 The ionic conductivity of (298 K) and the anodic stability window of up to 5 V were improved, and the corrosion current density and corrosion rate of the magnesium anode were reduced to 3.62 × 10⁻⁶. -5 A·cm -2 With 0.058 mg·cm -1 ·h -1 (Nearly 30 times lower than the uncoated sample). Furthermore, magnesium-air batteries can be fabricated into one-dimensional fiber structures and operate stably under bending, twisting, and other deformations. They can be woven in series into fabrics to drive wearable LED displays or integrated with photovoltaic modules as outdoor power systems to directly charge mobile phones, demonstrating excellent practical application potential.

[0045] Given that there are numerous embodiments of the present invention, and the raw materials and quantities involved can be selected within a limited range according to actual needs, and that the experimental data for each embodiment are extensive and numerous, it is not suitable to list and describe them one by one here. However, the content to be verified and the final conclusions obtained in each embodiment are similar. Therefore, the verification content of each embodiment will not be described one by one here.

[0046] The above description is merely a detailed explanation of preferred embodiments and principles of the present invention. For those skilled in the art, there may be changes in specific implementation methods based on the ideas provided by the present invention, and these changes should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a magnesium-air battery, characterized in that, Includes the following steps: (1) Dissolve magnesium bis(trifluoromethanesulfonyl)imide and chloride in a solvent, then add molecular sieve to dry and remove water, and obtain electrolyte after separation by molecular sieve; (2) Add N-methylpyrrolidone and poly(vinylidene fluoride-) to the electrolyte. co (-hexafluoropropylene), and added trimethylolpropane triacrylate as a crosslinking agent, and 2-hydroxy-2-methyl-1-phenyl-1-propanone reagent as an initiator during stirring to obtain a polymer gel electrolyte precursor; (3) The polymer gel electrolyte precursor is coated on the glass fiber membrane and cured by ultraviolet light. Then it is assembled with magnesium anode sheet and carbon nanotube thin film cathode to obtain magnesium air battery.

2. A method for preparing a magnesium-air fiber battery, characterized in that, Includes the following steps: (1) Dissolve magnesium bis(trifluoromethanesulfonyl)imide and chloride in a solvent, then add molecular sieve to dry and remove water, and obtain electrolyte after separation by molecular sieve; (2) Add N-methylpyrrolidone and poly(vinylidene fluoride-) to the electrolyte. co (-hexafluoropropylene), and added trimethylolpropane triacrylate as a crosslinking agent, and 2-hydroxy-2-methyl-1-phenyl-1-propanone reagent as an initiator during stirring to obtain a polymer gel electrolyte precursor; (3) The polymer gel electrolyte precursor was coated on magnesium wire and cured with ultraviolet light, and then assembled with carbon nanotube thin film cathode to obtain magnesium air fiber battery.

3. The preparation method according to claim 1 or 2, characterized in that, The molar ratio of the chloride salt to magnesium bis(trifluoromethylsulfonyl)imide is (1-5):

1.

4. The preparation method according to claim 1 or 2, characterized in that, The chloride salt is magnesium chloride, potassium chloride, sodium chloride, calcium chloride, or copper chloride.

5. The preparation method according to claim 1 or 2, characterized in that, The solvent is ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, or tetraethylene glycol dimethyl ether.

6. The preparation method according to claim 1 or 2, characterized in that, In step (2), the electrolyte, trimethylolpropane triacrylate, N-methylpyrrolidone, and poly(vinylidene fluoride) are used. co The mass ratio of the reagents 2-hexafluoropropylene and 2-hydroxy-2-methyl-1-phenyl-1-propanone is 4:4:4:(1-3):(0.01-0.1).

7. The preparation method according to claim 1 or 2, characterized in that, In step (3), the surface of the magnesium anode sheet or magnesium wire is first sanded to remove the surface oxide film. The carbon nanotube thin film cathode is first treated with nitric acid immersion to remove impurities.

8. The preparation method according to claim 1 or 2, characterized in that, In step (3), the UV curing time is 5 to 10 seconds.

9. A magnesium-air battery prepared by the method according to any one of claims 1, 3-8, characterized in that, The cycle life of the magnesium-air battery is no less than 100 cycles.

10. The magnesium-air battery according to any one of claims 2-8, characterized in that, The cycle life of the magnesium-air fiber battery is no less than 100 cycles.

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