Preparation method and application of three-dimensional porous negative material of magnesium secondary battery

Abstract

The application relates to the technical field of magnesium secondary batteries, in particular to a preparation method and application of a magnesium secondary battery three-dimensional porous negative electrode material. The chemical molecular formula of the magnesium secondary battery three-dimensional porous negative electrode material is Mg-xM, wherein M represents one or more of Ca, Sn, Li, Zn, Al, Gd, Si, Cu, Cd, Mn, Sr, Y, Re, Sc, Zr and Ag metal elements, and x is a mass fraction of 0-30 wt%. The method has the advantages of simple preparation method, low cost and uniform three-dimensional porous arrangement.

Description

Technical Field

[0001] This application relates to the field of magnesium secondary battery technology, and more specifically, to a method for preparing and applying a three-dimensional porous negative electrode material for magnesium secondary batteries. Background Technology

[0002] With the dwindling reserves of fossil fuels, primarily coal, oil, and natural gas, chemical power sources have gained significant attention in areas such as high-tech devices, green and low-energy transportation, and the development and utilization of renewable energy. However, the power sources currently in practical use are still traditional, toxic, and low-capacity lead-acid or silver-cadmium batteries. As the focus shifts towards energy, resources, and the environment, while addressing the problems of existing batteries, researchers have also begun developing new, high-performance, and low-cost green chemical power sources.

[0003] Magnesium secondary batteries, as one of the green chemical power sources, have attracted widespread attention from researchers due to their advantages such as high energy density, good safety performance, and low cost. Among these research directions, the preparation of novel magnesium metal anode materials and the study of their electrochemical performance in magnesium battery systems are important areas of research. During charge and discharge, magnesium secondary batteries gradually corrode the anode side, leading to dendritic growth caused by uneven magnesium deposition and dissolution. This results in serious problems such as shortened battery life, reduced capacity, and even battery failure. Numerous studies have shown that using three-dimensional structured materials as the anode in magnesium secondary batteries can achieve uniform magnesium deposition and dissolution, suppress dendrite growth, and thus improve the battery's cycle life, capacity, and safety performance.

[0004] In the existing technology, although the prepared three-dimensional framework material has good conductivity and magnesium affinity, the preparation process is relatively complicated and the raw material price is high. In addition, the equipment required is high-end and it is not easy to achieve large-scale production. The preparation of magnesium secondary battery anode material has the following disadvantages: (1) The preparation process is complicated, the equipment requirements are high, the cycle is long, and the environmental pollution is serious; (2) The size and distribution of the three-dimensional pore structure are uneven; (3) The cost is high and it is not easy to achieve large-scale production. Summary of the Invention

[0005] This disclosure provides a method for preparing a three-dimensional porous negative electrode material for magnesium secondary batteries and its application, which has the advantages of simple preparation method, low cost and uniform three-dimensional porous arrangement.

[0006] In a first aspect, a three-dimensional porous anode material for a magnesium secondary battery is provided, wherein the chemical formula of the three-dimensional porous anode material for the magnesium secondary battery is Mg-xM, where M represents one or more of the following metallic elements: Ca, Sn, Li, Zn, Al, Gd, Si, Cu, Cd, Mn, Sr, Y, Re, Sc, Zr, and Ag, and x is a mass fraction of 0-30 wt%.

[0007] The preparation of three-dimensional porous magnesium metal anode materials is low-cost, requires minimal equipment, and is suitable for large-scale production.

[0008] Secondly, this disclosure provides a method for preparing a three-dimensional porous negative electrode material for magnesium secondary batteries, including the following steps:

[0009] S1: The Mg-xM sample pretreatment involves processing the Mg-xM sample into a solid round rod with a diameter of 50-100mm and a height of 20-60mm, and then sanding it with sandpaper to remove the oxide layer.

[0010] S2: High pressure treatment. After assembling the sample in step S1, place it into a high-pressure six-sided press. Increase the pressure to 4-8 GPa, then increase the temperature to 800-1400℃ at a heating rate of 10℃ / min. Hold the temperature for 30-120 min, then turn off the power to stop heating, air cool to room temperature, and remove the high-pressure sample after depressurization.

[0011] S3: Chemical etching treatment. The Mg-xM sample after high pressure is processed into a cylindrical sheet with a thickness of 0.5-1mm and a diameter of 10-16mm. Then, it is polished with sandpaper to remove the oxide layer, cleaned with deionized water and ethanol, and then etched with organic acid solution. Finally, the etching products are removed with etching cleaning agent to obtain three-dimensional porous Mg-xM material.

[0012] Organic acid spraying corrosion process is simple, has a short cycle, is environmentally friendly, and the size and distribution of pores are controllable, with high pore structure stability.

[0013] Preferably, the organic acid in S3 includes one or more of the following: acetic acid, glycolic acid, aminosulfonic acid, picric acid, formic acid, oxalic acid, tartaric acid, citric acid, ethylenediaminetetraacetic acid, hydroxyethylidene diphosphoric acid, aminotrimethylphosphoric acid, and ethylenediaminetetramethylphosphoric acid.

[0014] Preferably, the concentration of the organic acid solution in S3 is 0.1-5 wt%. The corrosion time of the organic acid solution is 0.1-240 h.

[0015] Preferably, the corrosion cleaning agent in S3 is one or more of water, ethanol, chloroform, acetone, diethyl ether, benzene, methanol, toluene, ethyl acetate, and dimethylformamide.

[0016] Thirdly, this disclosure provides an application of a three-dimensional porous magnesium metal material, which is used as a negative electrode in a magnesium secondary battery assembly.

[0017] The prepared three-dimensional porous magnesium metal material, when used as the negative electrode, produces magnesium secondary batteries with excellent high-rate performance, high safety, and long cycle life.

[0018] Preferably, the electrolyte in the assembled magnesium secondary battery is one of the following: all-phenyl organoaluminum magnesium salt electrolyte, hexamethyldisilazane alkyl electrolyte, bis(trifluoromethanesulfonate)imide magnesium electrolyte, boron-based electrolyte, and inorganic magnesium chloride-based electrolyte.

[0019] Preferably, the separator in the assembled magnesium secondary battery is one of glass fiber separator, polyethylene separator, and polypropylene separator.

[0020] Preferably, the positive electrode material in the assembled magnesium secondary battery is one of the following: molybdenum octasulfide, carbon / sulfur composite material, vanadium pentoxide, cuprous sulfide, and manganese dioxide.

[0021] In summary, this application has the following beneficial effects:

[0022] 1. The three-dimensional porous magnesium metal material prepared in this application has low cost and low equipment requirements, making it suitable for large-scale production;

[0023] 2. The organic acid spraying corrosion process in this application is simple, has a short cycle, is environmentally friendly, and the size and distribution of the pores are controllable, with high pore structure stability.

[0024] 3. The three-dimensional porous magnesium metal material prepared in this application has excellent high-rate performance, high safety and long cycle life when used as a negative electrode in magnesium secondary batteries.

[0025] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit the scope of protection of this disclosure. Attached Figure Description

[0026] 1. Figure 1 This is a SEM image of Mg-3Al after etching, obtained in Application Example 1 of this invention;

[0027] 2. Figure 2 The pure Mg prepared in Example 2 of this invention was etched and then assembled into a symmetrical battery (1 mA cm⁻¹). -2 -1mAhcm -2 Electrochemical performance diagram;

[0028] 3. Figure 3 This is a metallographic image of Mg-0.15Ca obtained in Application Example 3 of this invention;

[0029] 4. Figure 4 The pure Mg-30Sn prepared in Example 4 of this invention was etched and then assembled into a symmetrical cell (3 mA cm⁻¹). -2 -3mAhcm -2 Electrochemical performance diagram of ). Detailed Implementation

[0030] The following detailed description of this application is provided in conjunction with the embodiments. It should be noted that: unless otherwise specified, the conditions in the following embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following embodiments are all from commercially available sources.

[0031] Example

[0032] Example 1

[0033] A method for preparing a three-dimensional porous negative electrode material for magnesium secondary batteries includes the following steps:

[0034] 1) High-pressure treatment of Mg-3Al samples: The surface of the Mg-3Al sample, with a height of 20 mm and a diameter of 100 mm, was cleaned with sandpaper to remove the surface oxide layer. After the sample was assembled, it was placed in the cavity of a high-pressure six-sided press. After the hammers were aligned, high-pressure treatment was performed. The pressure was increased to 4 GPa, and the temperature was increased to 1200℃ at a heating rate of 10℃ / min. The temperature was held for 60 min, then the power was turned off to stop heating, and the sample was air-cooled to room temperature. After depressurization, the high-pressure sample was removed.

[0035] 2) Chemical corrosion of Mg-3Al samples: High-pressure treated Mg-3Al samples were machined into cylindrical substrates with a thickness of 0.7 mm and a diameter of 12 mm using a wire EDM machine. The Mg-3Al surface was successively ground and polished using 400#, 800#, 1500#, and 2000# sandpaper. The samples were then cleaned with deionized water and ethanol and dried at room temperature. A spray gun containing a 3.5 wt% acetic acid solution was used to spray the sample surface. After 36 hours, the corrosion products were removed with water. A three-dimensional porous Mg-3Al anode material was obtained.

[0036] Example 2

[0037] A method for preparing a three-dimensional porous negative electrode material for magnesium secondary batteries includes the following steps:

[0038] 1) High-pressure treatment of pure Mg samples: The surface of a pure Mg sample with a height of 60 mm and a diameter of 50 mm was cleaned with sandpaper to remove the surface oxide layer. After the sample was assembled, it was placed in the cavity of a high-pressure six-sided press. After the hammers were aligned, high-pressure treatment was performed. The pressure was increased to 8 GPa, and the temperature was increased to 800℃ at a heating rate of 10℃ / min. The temperature was held for 30 min, then the power was turned off to stop heating. The sample was then air-cooled to room temperature, and the high-pressure sample was removed after depressurization.

[0039] 2) Chemical corrosion of pure Mg samples: High-pressure treated pure Mg samples were machined into cylindrical substrates with a thickness of 0.5 mm and a diameter of 10 mm using a wire cutting machine. The surface of the pure Mg was successively polished using 400#, 800#, 1500#, and 2000# sandpaper. The samples were then cleaned with deionized water and ethanol and dried at room temperature. A spray gun containing a 0.9 wt% ethylenediaminetetramethylphosphoric acid solution was used to spray the sample surface. After 24 hours, the corrosion products were removed with acetone. A three-dimensional porous pure Mg anode material was obtained.

[0040] Example 3

[0041] A method for preparing a porous negative electrode material for a magnesium secondary battery includes the following steps:

[0042] 1) High-pressure treatment of Mg-0.15Ca samples: The surface of the Mg-0.15Ca sample, with a height of 30 mm and a diameter of 70 mm, was cleaned with sandpaper to remove the surface oxide layer. After the sample was assembled, it was placed in the cavity of a high-pressure six-sided press. After the hammers were aligned, high-pressure treatment was performed. The pressure was increased to 6 GPa, and the temperature was increased to 1100℃ at a heating rate of 10℃ / min. The temperature was held for 30 min, then the power was turned off to stop heating, and the sample was air-cooled to room temperature. After depressurization, the high-pressure sample was removed.

[0043] 2) Chemical corrosion of Mg-0.15Ca samples: High-pressure treated Mg-0.15Ca samples were machined into cylindrical substrates with a thickness of 1 mm and a diameter of 16 mm using a wire cutting machine. The surface of the Mg-0.15Ca samples was successively ground and polished using 400#, 800#, 1500#, and 2000# sandpaper. The samples were then cleaned with deionized water and ethanol and dried at room temperature. A spray gun containing a 5 wt% aminosulfonic acid solution was used to spray the sample surface. After 0.1 h, the corrosion products were removed with ammonia. A three-dimensional porous Mg-0.15Ca anode material was obtained.

[0044] Example 4

[0045] A method for preparing a porous negative electrode material for a magnesium secondary battery includes the following steps:

[0046] 1) High-pressure treatment of Mg-30Sn samples: The surface of the Mg-30Sn sample, with a height of 30mm and a diameter of 80mm, was cleaned with sandpaper to remove the surface oxide layer. After the sample was assembled, it was placed in the cavity of a high-pressure six-sided press. After the hammers were aligned, high-pressure treatment was performed. The pressure was increased to 4GPa, and the temperature was increased to 1400℃ at a heating rate of 10℃ / min. The temperature was held for 120min, then the power was turned off to stop heating, and the sample was air-cooled to room temperature. After depressurization, the high-pressure sample was removed.

[0047] 2) Chemical corrosion of Mg-30Sn samples: High-pressure treated Mg-30Sn samples were machined into cylindrical substrates with a thickness of 0.7 mm and a diameter of 12 mm using a wire EDM machine. The surface of the Mg-30Sn was successively polished using 400#, 800#, 1500#, and 2000# sandpaper. The samples were then cleaned with deionized water and ethanol and dried at room temperature. A spray gun containing a 0.1 wt% citric acid solution was used to spray the sample surface. After 240 hours, the corrosion products were removed with methanol. A three-dimensional porous Mg-30Sn anode material was obtained.

[0048] Application examples

[0049] Application Example 1

[0050] A magnesium secondary battery was assembled using the three-dimensional porous Mg-3Al prepared in Example 1 as the negative electrode. The electrolyte, separator and positive electrode materials were selected as all-phenyl organic aluminum magnesium salt electrolyte, glass fiber separator and sulfur-carbon composite positive electrode material, respectively. The performance of the assembled battery was tested using a Blue Battery Testing System and an electrochemical workstation.

[0051] like Figure 1 This is a microscopic morphology image of Mg-3Al after corrosion in a 3.5wt% acetic acid solution for 36 hours. As can be seen from the image, a large number of tightly packed 3D porous structures with uniform pore size were formed on the surface of the Mg-3Al sample, with an average diameter of 1μm.

[0052] Application Example 2

[0053] A magnesium secondary battery is assembled using three-dimensional porous pure Mg as the negative electrode. The electrolyte, separator, and positive electrode materials are respectively selected as all-phenyl organoaluminum magnesium salt electrolyte, glass fiber separator, and manganese dioxide positive electrode material. The performance of the assembled battery is tested using a Blue Battery Testing System and an electrochemical workstation.

[0054] like Figure 2 This is an electrochemical performance graph of a symmetrical cell assembled using pure Mg as the negative electrode material after being etched in a 0.9 wt% ethylenediaminetetramethylphosphoric acid solution for 24 hours. The voltage and cycle time graphs show that the etched pure Mg sample exhibits the best performance at 1 mA / cm². -2 -1mAhcm -2 Under certain conditions, it exhibits excellent cycling stability, low deposition overpotential, and long cycle life.

[0055] Application Example 3

[0056] A magnesium secondary battery is assembled using three-dimensional porous Mg-0.15Ca as the negative electrode. The electrolyte, separator, and positive electrode materials are respectively selected as bis(trifluoromethanesulfonate)imide magnesium electrolyte, polyethylene separator, and cuprous sulfide positive electrode material. The performance of the assembled battery is tested using a Blue Battery Testing System and an electrochemical workstation.

[0057] like Figure 3 The image shows a metallographic image of Mg-0.15Ca. It can be seen that Mg-0.15Ca has uniform grain size, narrow grain boundaries, and a certain number of twins within the grains. This facilitates preferential etching along the twinning direction to obtain a uniform three-dimensional porous structure.

[0058] Application Example 4

[0059] A magnesium secondary battery is assembled using three-dimensional porous Mg-30Sn as the negative electrode. The electrolyte, separator, and positive electrode materials are respectively selected from inorganic magnesium chloride-based electrolyte, polypropylene separator, and molybdenum octasulfide positive electrode material. The performance of the assembled battery is tested using a Blue Battery Testing System and an electrochemical workstation.

[0060] like Figure 4 The figures show the electrochemical performance of a symmetrical cell assembled using Mg-30Sn as the negative electrode material after being etched in a 0.1 wt% citric acid solution for 240 h. The performance figures show that the etched Mg-30Sn sample exhibits excellent performance at 3 mA / cm². -2 -3mAhcm -2 It can stably cycle for more than 160 times under high-rate and large-capacity conditions.

[0061] The above description is merely an exemplary embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A method for preparing a three-dimensional porous magnesium metal material, characterized in that, Includes the following steps: S1: Pretreatment of Mg-xM sample: The Mg-xM sample is processed into a solid round bar with a diameter of 50-100mm and a height of 20-60mm, and then the oxide layer is removed by sanding. S2: High-pressure treatment. After assembling the sample from step S1, place it in a high-pressure six-sided press. Increase the pressure to 4-8 GPa, then raise the temperature to 800-1400℃ at a heating rate of 10℃ / min, hold for 30-120 min, then turn off the power to stop heating, air cool to room temperature, and remove the high-pressure sample after depressurization. The high-pressure sample has uniform grain size, and the grains have a twinned structure inside. S3: Chemical etching treatment. The high-pressure sample obtained in step S2 is processed into a cylindrical sheet with a thickness of 0.5-1 mm and a diameter of 10-16 mm. Then, it is polished with sandpaper to remove the oxide layer, cleaned with deionized water and ethanol, and then etched with an organic acid solution. Finally, the etching products are removed with an etching cleaning agent to obtain a three-dimensional porous magnesium metal material. The three-dimensional porous magnesium metal material has a 3D porous structure with a tight arrangement and uniform pore size. The average pore diameter of the 3D porous structure is 1 μm. The chemical formula of the three-dimensional porous magnesium metal material is Mg-xM, where M represents one or more of the metal elements Ca, Sn, and Al, and x is a mass fraction of 0-30 wt%. The organic acids in S3 include one or more of the following: acetic acid, glycolic acid, aminosulfonic acid, picric acid, formic acid, oxalic acid, tartaric acid, citric acid, ethylenediaminetetraacetic acid, hydroxyethylidene diphosphoric acid, aminotrimethylphosphoric acid, and ethylenediaminetetramethylphosphoric acid. The concentration of the organic acid solution in S3 is 0.1-5 wt%; the corrosion time of the organic acid solution is 0.1-240 h.

2. The preparation method according to claim 1, characterized in that, The corrosion cleaning agent in S3 is one or more of water, ethanol, chloroform, acetone, diethyl ether, benzene, methanol, toluene, ethyl acetate, and dimethylformamide.

3. A three-dimensional porous magnesium metal material prepared by the preparation method of the three-dimensional porous magnesium metal material according to claim 1 or 2.

4. An application of a three-dimensional porous magnesium metal material prepared by the method of claim 1 or 2, characterized in that, The three-dimensional porous magnesium metal material is used as the negative electrode to assemble a magnesium secondary battery.

5. The application of the three-dimensional porous magnesium metal material according to claim 4, characterized in that, The electrolyte in the assembled magnesium secondary battery is one of the following: all-phenyl organoaluminum magnesium salt electrolyte, hexamethyldisilazane alkyl electrolyte, bis(trifluoromethanesulfonate)imide magnesium electrolyte, boron-based electrolyte, and inorganic magnesium chloride-based electrolyte.

6. The application of the three-dimensional porous magnesium metal material according to claim 4, characterized in that, The separator in the assembled magnesium secondary battery is one of glass fiber separator, polyethylene separator, or polypropylene separator.

7. The application of the three-dimensional porous magnesium metal material according to claim 4, characterized in that, The positive electrode material in the assembled magnesium secondary battery is one of the following: molybdenum octasulfide, carbon / sulfur composite material, vanadium pentoxide, cuprous sulfide, and manganese dioxide.

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