Preparation method of magnesium sulfide / MXene composite material, product and application thereof

Abstract

The application discloses a preparation method of magnesium sulfide / MXene composite material, and products and applications thereof. Lithium halide is added into strong acid to dissolve Ti3AlC2 powder, and the treated Ti3AlC2 powder is collected when the pH value is 6 after washing, centrifugation, vacuum drying, ultrasonic bath and centrifugation. The green supernatant is collected to obtain a layered MXene colloidal suspension. The MXene dispersion liquid and oleylamine are stirred to form an emulsion. The mixed dispersion is heated to form Mg-O-X / MXene. A solution containing thioacetamide in oleylamine is injected into the three-necked bottle. After heating, stirring, cooling, washing, centrifugation and freeze drying, the magnesium sulfide / MXene composite material is obtained. The first discharge specific capacity of the magnesium sulfide / MXene composite material is 199.7 mAh / g at a current density of 500 mA / g, and the discharge specific capacity is 187 mAh / g after 50 cycles, and the capacity retention rate is 93.6%.

Description

Technical Field

[0001] This invention relates to a method for preparing magnesium ion cathode materials, and particularly to a method for preparing magnesium sulfide / MXene composite materials, as well as their products and applications. Background Technology

[0002] With the development of human society, the contradiction between the global shortage of energy resources and the ever-increasing demand for energy is becoming increasingly acute. Developing battery systems with high energy density has become a major goal of current power systems. Although lithium-ion batteries, with their high specific energy and environmental friendliness, are widely used in portable mobile devices such as mobile phones and laptops, as well as in electric bicycles and electric vehicles, their safety remains a significant concern, and much work remains to be done in their application as power batteries. Magnesium, one of the most abundant light metal elements on Earth, is widely used in many fields due to its excellent physicochemical properties. Current research on rechargeable magnesium batteries is largely based on rechargeable lithium-ion batteries. Since magnesium and lithium are diagonally opposite each other in the periodic table, besides having similar atomic radii and chemical properties, magnesium has a much higher melting point (648.8 ℃) than lithium (180.5 ℃) and is less reactive, making rechargeable magnesium batteries safer. Although their specific capacity is lower than lithium (3862 mAh g⁻¹), rechargeable magnesium batteries offer better safety. -1 That's high, but still quite considerable (2205 mAh g). -1 Moreover, my country has extremely abundant magnesium resources, and the price of magnesium is much lower than that of lithium. Furthermore, magnesium is environmentally friendly, so rechargeable magnesium batteries are attracting increasing attention.

[0003] Magnesium sulfide is a cubic sulfide commonly used as a wide bandgap semiconductor. It can also be used as a cathode material for magnesium-ion batteries and is considered a promising magnesium-ion cathode material.

[0004] This invention provides a method for preparing a magnesium sulfide / Mxene (Mxene is a two-dimensional material) composite material. The prepared material has a large specific surface area. The large specific surface area not only facilitates the full contact between the active material and the electrolyte, but also helps to shorten the electron diffusion rate, thereby improving the electrochemical properties of the material. Summary of the Invention

[0005] To overcome the shortcomings of existing magnesium sulfide electrochemical performance, the present invention aims to provide a method for preparing magnesium sulfide / MXene composite materials.

[0006] Another object of the present invention is to provide a magnesium sulfide / MXene composite material product obtained by the above method.

[0007] Another object of the present invention is to provide an application of the above-mentioned product.

[0008] The objective of this invention is achieved through the following method: a method for preparing a magnesium sulfide / MXene composite material, comprising the following steps:

[0009] (1) Add 0.8–1 g of lithium halide to a strong acid solution (10 mL, 9 mol) until completely dissolved to obtain solution A; slowly add 0.5–0.8 g of Ti3AlC2 powder to solution A, heat at 35–45 °C for 18–24 h under magnetic stirring, wash and centrifuge the slurry, collect the treated Ti3AlC2 powder when the pH value is 6, and dry it overnight in a vacuum oven at 60–80 °C to obtain powder B. Mix powder B (1 g) with deionized water (200 mL) and sonicate in an Ar flowing atmosphere for 1–2 h. After centrifugation at 3500–3800 rpm for 40–60 min, collect the green supernatant in the dark to obtain a layered MXene colloidal suspension.

[0010] (2) Add 2 mL of MXene dispersion (5 mg / mL) −1 Add 20 mL of oleylamine to a three-necked flask and stir to form an emulsion. Then, under room temperature conditions, use a vacuum pump to remove water vapor from the emulsion until no more bubbles appear. Next, inject 10 mL of oleylamine containing 0.35–0.5 mmol of magnesium halide into the three-necked flask. Afterward, heat the mixture to 150–170 °C for 5–10 min to form Mg-OX / MXene (where X is a halogen element, such as F, Cl, or Br).

[0011] (3) Pour 10 mL of a solution containing 1.05–1.1 mmol of thioacetamide into the three-necked flask. Heat the flask to 160–180 °C and stir for 30–50 min. When the three-necked flask cools to room temperature, wash the resulting solution 3–5 times with solvent and centrifuge. Finally, freeze-dry the resulting precipitate to obtain the magnesium sulfide / MXene composite material.

[0012] Preferably, in step (1), the lithium halide is one or a combination of lithium fluoride, lithium chloride, or lithium bromide.

[0013] Preferably, in step (1), the strong acid is one of hydrochloric acid and nitric acid, or a combination thereof.

[0014] Preferably, in step (2), the magnesium halide is one or a combination of magnesium fluoride, magnesium chloride, and magnesium bromide.

[0015] Preferably, in step (3), the solvent is one or a combination of anhydrous ethanol, acetone, or the solvent itself.

[0016] This invention provides a magnesium sulfide / MXene composite material, prepared according to any of the methods described above.

[0017] This invention provides an application of magnesium sulfide / MXene composite material in battery cathode materials.

[0018] Beneficial effects:

[0019] This invention provides a method for preparing a magnesium sulfide / MXene composite material. The prepared material has a large specific surface area. This large specific surface area not only facilitates sufficient contact between the active material and the electrolyte but also shortens the electron diffusion rate, thereby improving the electrochemical properties of the material. The magnesium sulfide / MXene composite material exhibits an initial discharge specific capacity of 199.7 mAh / g at a current density of 500 mA / g, and after 50 cycles, its discharge specific capacity is 187 mAh / g, with a capacity retention of 93.6%. Attached Figure Description

[0020] Figure 1 This is a cycle life diagram for magnesium sulfide / MXene in Example 1. Detailed Implementation

[0021] The present invention will be described in detail through the following specific examples, but the scope of protection of the present invention is not limited to these embodiments.

[0022] Example 1

[0023] A magnesium sulfide / MXene composite material is prepared according to the following steps:

[0024] (1) Preparation of MXene colloidal suspension:

[0025] 0.8 g of lithium fluoride was added to 10 mL of 9 mol hydrochloric acid solution until completely dissolved to obtain solution A; 0.5 g of Ti3AlC2 powder was slowly added to solution A, and heated at 35 °C for 24 h under magnetic stirring. The slurry was washed and centrifuged. When the pH value was 6, the treated Ti3AlC2 powder was collected and dried overnight in a vacuum oven at 60 °C to obtain powder B; 1 g of powder B was mixed with 200 mL of deionized water and ultrasonicated in an Ar flowing atmosphere for 1 h; after centrifugation at 3500 rpm for 60 min, the green supernatant was collected in the dark to obtain a layered MXene colloidal suspension.

[0026] (2) Preparation of Mg-OX / MXene:

[0027] 2 mL of a 5 mg / mL solution −1 After adding MXene dispersion and 20 mL of oleylamine to a three-necked flask and stirring to form an emulsion, the water vapor in the emulsion was removed at room temperature using a vacuum pump until no more bubbles appeared. Then, 10 mL of oleylamine containing 0.35 mmol of magnesium fluoride was injected into the three-necked flask, and the mixture was heated at 150 °C for 10 min to form Mg-OF / MXene.

[0028] (3) Preparation of magnesium sulfide / MXene composite material:

[0029] A solution containing 1.05 mmol of thioacetamide in 10 mL of oleylamine was injected into the three-necked flask and heated to 180 °C with stirring for 30 min. When the three-necked flask was cooled to room temperature, the resulting solution was washed five times with anhydrous ethanol, centrifuged, and the resulting precipitate was freeze-dried to obtain magnesium sulfide / MXene composite material.

[0030] Figure 1 This diagram shows the cycle life of magnesium sulfide / Mxene at a current density of 500 mA / g in this embodiment. The initial discharge specific capacity of magnesium sulfide / Mxene at 500 mA / g is 199.7 mAh / g, and after 50 cycles, its discharge specific capacity is 187 mAh / g, with a capacity retention of 93.6%.

[0031] Example 2

[0032] A magnesium sulfide / MXene composite material is prepared according to the following steps:

[0033] (1) Preparation of MXene colloidal suspension:

[0034] 1 g of lithium chloride was added to 10 mL of 9 mol nitric acid solution until completely dissolved to obtain solution A; 0.8 g of Ti3AlC2 powder was slowly added to solution A and heated at 45°C for 18 h under magnetic stirring. The slurry was washed and centrifuged. When the pH value was 6, the treated Ti3AlC2 powder was collected and dried overnight in a vacuum oven at 60°C to obtain powder B; 1 g of powder B was mixed with 200 mL of deionized water and ultrasonicated in an Ar flowing atmosphere for 2 h; after centrifugation at 3800 rpm for 40 min, the green supernatant was collected in the dark to obtain a layered MXene colloidal suspension.

[0035] (2) Preparation of Mg-OX / MXene:

[0036] 2 mL of a 5 mg / mL solution −1MXene dispersion and 20 mL of oleylamine were added to a three-necked flask and stirred to form an emulsion. Then, the water vapor in the emulsion was removed at room temperature using a vacuum pump until no more bubbles appeared. After injecting 10 mL of oleylamine containing 0.5 mmol of magnesium chloride into the three-necked flask, the mixture was heated at 170 °C for 5 min to form Mg-O-Cl / MXene.

[0037] (3) Preparation of magnesium sulfide / MXene composite material:

[0038] A solution containing 1.1 mmol of thioacetamide in 10 mL of oleylamine was injected into the three-necked flask and heated to 160 °C and stirred for 50 min. When the three-necked flask was cooled to room temperature, the resulting solution was washed five times with acetone, centrifuged, and the resulting precipitate was freeze-dried to obtain magnesium sulfide / MXene composite material.

[0039] Example 3

[0040] A magnesium sulfide / MXene composite material is prepared according to the following steps:

[0041] (1) Preparation of MXene colloidal suspension:

[0042] 1 g of lithium bromide was added to 10 mL of 9 mol hydrochloric acid solution until completely dissolved to obtain solution A; 0.8 g of Ti3AlC2 powder was slowly added to solution A, and heated at 45°C for 18 h under magnetic stirring. The slurry was washed and centrifuged. When the pH value was 6, the treated Ti3AlC2 powder was collected and dried overnight in a vacuum oven at 80°C to obtain powder B; 1 g of powder B was mixed with 200 mL of deionized water and ultrasonicated in an Ar flowing atmosphere for 2 h; after centrifugation at 3600 rpm for 50 min, the green supernatant was collected in the dark to obtain a layered MXene colloidal suspension.

[0043] (2) Preparation of Mg-OX / MXene:

[0044] 2 mL of a 5 mg / mL solution −1 MXene dispersion and 20 mL of oleylamine were added to a three-necked flask and stirred to form an emulsion. Then, water vapor in the emulsion was removed at room temperature using a vacuum pump until no more bubbles appeared. Then, 10 mL of oleylamine containing 0.4 mmol of magnesium bromide was injected into the three-necked flask, and the mixture was heated at 160 °C for 8 min to form Mg-O-Br / MXene.

[0045] (3) Preparation of magnesium sulfide / MXene composite material:

[0046] A solution containing 1.05 mmol of thioacetamide in 10 mL of oleylamine was injected into the three-necked flask, and the mixture was heated to 180 °C and stirred for 30 min. After the flask cooled to room temperature, the resulting solution was washed five times with anhydrous ethanol, centrifuged, and the resulting precipitate was freeze-dried to obtain the magnesium sulfide / MXene composite material.

[0047] .

Claims

1. A method for preparing a magnesium sulfide / MXene composite material, characterized in that, Includes the following steps: (1) Preparation of MXene colloidal suspension: 0.8–1 g of lithium halide was added to 10 mL of a 9 mol strong acid solution until completely dissolved to obtain solution A. 0.5–0.8 g of Ti3AlC2 powder was slowly added to solution A and heated at 35–45 °C for 18–24 h under magnetic stirring. The slurry was washed and centrifuged. When the pH value was 6, the treated Ti3AlC2 powder was collected and dried overnight in a vacuum oven at 60–80 °C to obtain powder B. 1 g of powder B was mixed with 200 mL of deionized water and ultrasonicated in an Ar flowing atmosphere for 1–2 h. After centrifugation at 3500–3800 rpm for 40–60 min, the green supernatant was collected in the dark to obtain a layered MXene colloidal suspension. (2) Preparation of Mg-OX / MXene: 2 mL of a 5 mg / mL MXene dispersion and 20 mL of oleylamine were added to a three-necked flask and stirred to form an emulsion. Then, the water vapor in the emulsion was removed at room temperature using a vacuum pump until no more bubbles appeared. Next, 10 mL of a solution containing 0.35–0.5 mmol of magnesium halide in oleylamine was injected into the three-necked flask, and the mixture was heated at 150–170 °C for 5–10 min to form Mg-OX / MXene, where X is a halogen element including F, Cl, or Br. (3) Preparation of magnesium sulfide / MXene composite material: A solution containing 1.05–1.1 mmol of thioacetamide in 10 mL of oleylamine was injected into the above three-necked flask, heated to 160–180 °C and stirred for 30–50 min. When the three-necked flask was cooled to room temperature, the resulting solution was washed 3–5 times with solvent, centrifuged, and the resulting precipitate was freeze-dried to obtain magnesium sulfide / MXene composite material.

2. The method for preparing a magnesium sulfide / MXene composite material according to claim 1, characterized in that, The lithium halide is one or a combination of lithium fluoride, lithium chloride, or lithium bromide.

3. The method for preparing a magnesium sulfide / MXene composite material according to claim 1, characterized in that, The strong acid mentioned is one of hydrochloric acid and nitric acid, or a combination thereof.

4. The method for preparing a magnesium sulfide / MXene composite material according to claim 1, characterized in that... The magnesium halide mentioned is one or a combination of magnesium fluoride, magnesium chloride, and magnesium bromide.

5. The method for preparing a magnesium sulfide / MXene composite material according to claim 1, characterized in that... The solvent is one or a combination of anhydrous ethanol, acetone, or the solvent mentioned above.

6. The method for preparing a magnesium sulfide / MXene composite material according to any one of claims 1 to 5, characterized in that, Follow these steps: (1) Preparation of MXene colloidal suspension: 0.8 g of lithium fluoride was added to 10 mL of 9 mol hydrochloric acid solution until completely dissolved to obtain solution A; 0.5 g of Ti3AlC2 powder was slowly added to solution A, and heated at 35 °C for 24 h under magnetic stirring. The slurry was washed and centrifuged. When the pH value was 6, the treated Ti3AlC2 powder was collected and dried overnight in a vacuum oven at 60 °C to obtain powder B; 1 g of powder B was mixed with 200 mL of deionized water and ultrasonicated in an Ar flowing atmosphere for 1 h; after centrifugation at 3500 rpm for 60 min, the green supernatant was collected in the dark to obtain a layered MXene colloidal suspension. (2) Preparation of Mg-OX / MXene: 2 mL of a 5 mg / mL MXene dispersion and 20 mL of oleylamine were added to a three-necked flask and stirred to form an emulsion. The water vapor in the emulsion was then removed at room temperature using a vacuum pump until no more bubbles appeared. Then, 10 mL of a solution containing 0.35 mmol magnesium fluoride in oleylamine was injected into the three-necked flask, and the mixture was heated at 150 °C for 10 min to form Mg-OF / MXene. (3) Preparation of magnesium sulfide / MXene composite material: A solution containing 1.05 mmol of thioacetamide in 10 mL of oleylamine was injected into the above three-necked flask, heated to 180 °C and stirred for 30 min. When the three-necked flask was cooled to room temperature, the resulting solution was washed 5 times with anhydrous ethanol, centrifuged, and the resulting precipitate was freeze-dried to obtain magnesium sulfide / MXene composite material.

7. A method for preparing a magnesium sulfide / MXene composite material according to any one of claims 1 to 5, characterized in that, Follow these steps: 1 g of lithium chloride was added to 10 mL of 9 mol nitric acid solution until completely dissolved to obtain solution A; 0.8 g of Ti3AlC2 powder was slowly added to solution A, and heated at 45 °C for 18 h under magnetic stirring. The slurry was washed and centrifuged. When the pH value was 6, the treated Ti3AlC2 powder was collected and dried overnight in a vacuum oven at 60 °C to obtain powder B; 1 g of powder B was mixed with 200 mL of deionized water and ultrasonicated in an Ar flowing atmosphere for 2 h; after centrifugation at 3800 rpm for 40 min, the green supernatant was collected in the dark to obtain a layered MXene colloidal suspension. (2) Preparation of Mg-OX / MXene: 2 mL of 5 mg / mL MXene dispersion and 20 mL of oleylamine were added to a three-necked flask and stirred to form an emulsion. Then, the water vapor in the emulsion was removed by a vacuum pump at room temperature until no more bubbles appeared. 10 mL of oleylamine solution containing 0.5 mmol magnesium chloride was injected into the three-necked flask, and the mixture was heated at 170 °C for 5 min to form Mg-O-Cl / MXene. (3) Preparation of magnesium sulfide / MXene composite material: A solution containing 1.1 mmol of thioacetamide in 10 mL of oleylamine was injected into the above three-necked flask, heated to 160 °C and stirred for 50 min. When the three-necked flask was cooled to room temperature, the resulting solution was washed 5 times with acetone, centrifuged, and the resulting precipitate was freeze-dried to obtain magnesium sulfide / MXene composite material.

8. A method for preparing a magnesium sulfide / MXene composite material according to any one of claims 1 to 5, characterized in that, Follow these steps: (1) Preparation of MXene colloidal suspension: 1 g of lithium bromide was added to 10 mL of 9 mol hydrochloric acid solution until completely dissolved to obtain solution A; 0.8 g of Ti3AlC2 powder was slowly added to solution A, and heated at 45 °C for 18 h under magnetic stirring. The slurry was washed and centrifuged. When the pH value was 6, the treated Ti3AlC2 powder was collected and dried overnight in a vacuum oven at 80 °C to obtain powder B; 1 g of powder B was mixed with 200 mL of deionized water and ultrasonicated in an Ar flowing atmosphere for 2 h; after centrifugation at 3600 rpm for 50 min, the green supernatant was collected in the dark to obtain a layered MXene colloidal suspension. (2) Preparation of Mg-OX / MXene: 2 mL of a 5 mg / mL MXene dispersion and 20 mL of oleylamine were added to a three-necked flask and stirred to form an emulsion. Then, the water vapor in the emulsion was removed by a vacuum pump at room temperature until no more bubbles appeared. Then, 10 mL of oleylamine containing 0.4 mmol magnesium bromide was injected into the three-necked flask, and the mixture was heated at 160 °C for 8 min to form Mg-O-Br / MXene. (3) Preparation of magnesium sulfide / MXene composite material: A solution containing 1.05 mmol of thioacetamide in 10 mL of oleylamine was injected into the above three-necked flask, heated to 180 °C and stirred for 30 min. When the three-necked flask was cooled to room temperature, the resulting solution was washed 5 times with anhydrous ethanol, centrifuged, and the resulting precipitate was freeze-dried to obtain magnesium sulfide / MXene composite material.

9. A magnesium sulfide / MXene composite material, characterized in that... Prepared by the method according to any one of claims 1-8.

10. The application of the magnesium sulfide / MXene composite material according to claim 9 in battery cathode materials.

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