A lithium-sulfur battery positive electrode material and preparation method thereof

Abstract

The present invention discloses a lithium-sulfur battery cathode material and its preparation method, comprising the following steps: adding asphalt and sulfur powder to an organic solvent, volatilizing the organic solvent to obtain a first precursor; mixing the first precursor with an absorbing material and grinding the mixture to obtain a second precursor; heating the second precursor in a microwave reactor under a protective atmosphere to obtain a third precursor; and ball-milling the third precursor to obtain the lithium-sulfur battery cathode material. The asphalt absorbs the sulfur powder, which is then rapidly carbonized by microwave reaction, thereby minimizing sulfur loss. The resulting lithium-sulfur battery cathode material has excellent electrochemical properties. The preparation method is simple, low-cost, and energy-efficient, making it suitable for industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium-sulfur batteries, and in particular to a lithium-sulfur battery positive electrode material and a preparation method thereof. Background Art

[0002] Due to its extremely high theoretical specific capacity (1670 mAh / g), elemental sulfur is considered the most promising cathode material for next-generation lithium secondary batteries. The theoretical specific energy and volumetric energy density of a lithium-sulfur battery system can reach 2600 Wh / kg and 2800 Wh / L, respectively, far exceeding the specific energy of existing lithium-ion batteries. Furthermore, sulfur offers the advantages of being inexpensive, abundant, and environmentally friendly, making it a promising candidate for providing a lightweight power source and support for current electric vehicles. These advantages have made lithium-sulfur batteries a research hotspot worldwide.

[0003] Due to the insulating properties of elemental sulfur, it cannot be used alone as a positive electrode material. It is usually compounded with a conductive material to improve its conductivity and thus optimize its electrochemical performance. According to the characteristics of sulfur, the current common method for preparing sulfur-carbon composite materials is to first prepare a carbon carrier material, and then inject the sulfur element into the porous carbon material through methods such as melt diffusion, chemical precipitation, and vapor infiltration. However, the preparation process of existing sulfur-carbon composite materials is relatively complicated. It is necessary to first perform a carbonization process to prepare the carbon carrier material, and then load sulfur into the carbon material. The cost is high and the scope of use is small. Therefore, it is of great significance to develop a low-cost, wide-scope, and simple process preparation method for sulfur-carbon composite materials.

[0004] Therefore, the existing technology still needs to be improved and developed. Summary of the Invention

[0005] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a lithium-sulfur battery positive electrode material and a preparation method thereof, so as to solve the problems of complex process and long time in the prior art for preparing lithium-sulfur battery positive electrode materials, and to realize the preparation of sulfur-carbon composite materials as lithium-sulfur battery positive electrode materials in an ultra-short time.

[0006] The technical solutions of the present invention are as follows:

[0007] A method for preparing a positive electrode material for a lithium-sulfur battery, comprising the steps of:

[0008] adding asphalt and sulfur powder into an organic solvent, and volatilizing the organic solvent to obtain a first precursor;

[0009] Mixing the first precursor with an absorbing material and grinding the mixture to obtain a second precursor;

[0010] placing the second precursor in a microwave reactor under a protective atmosphere and performing microwave heating to obtain a third precursor;

[0011] The third precursor is ball-milled to obtain the lithium-sulfur battery positive electrode material.

[0012] The method for preparing the positive electrode material of a lithium-sulfur battery, wherein the step of adding asphalt and sulfur powder to an organic solvent and volatilizing the organic solvent to obtain a first precursor, specifically comprises: dissolving asphalt in toluene, adding sulfur powder so that the asphalt is uniformly adsorbed on the surface of the sulfur powder, and volatilizing the toluene to obtain the first precursor.

[0013] The method for preparing the positive electrode material of a lithium-sulfur battery, wherein the mass ratio of the asphalt to the sulfur powder is 1:(1.33-15).

[0014] In the method for preparing the positive electrode material for a lithium-sulfur battery, the concentration of the asphalt dissolved in the toluene is 0.1 to 1 g / mL.

[0015] The method for preparing the positive electrode material of a lithium-sulfur battery, wherein the first precursor is mixed with an absorbing material and ground to obtain a second precursor, specifically comprises: mixing the first precursor with carbon powder and grinding for 10 to 30 minutes to obtain the second precursor.

[0016] In the method for preparing the positive electrode material of a lithium-sulfur battery, the mass ratio of the carbon powder to the first precursor is 1:(25-360).

[0017] The method for preparing the positive electrode material of a lithium-sulfur battery, wherein the mass ratio of the first precursor to the carbon powder is: placing the second precursor in a microwave reactor under a protective atmosphere for microwave heating to obtain a third precursor, specifically comprising: placing the second precursor in a microwave reactor under a nitrogen atmosphere for microwave heating, and reacting at 650°C to obtain the third precursor.

[0018] The method for preparing the positive electrode material of a lithium-sulfur battery, wherein the microwave power of the microwave heating in the microwave reactor is 400-800W, and the reaction time is 10-300s.

[0019] The method for preparing the lithium-sulfur battery positive electrode material, wherein the ball milling of the third precursor to obtain the lithium-sulfur battery positive electrode material specifically comprises: ball milling the third precursor at a rotation speed of 200 to 600 rpm for 30 to 90 minutes to obtain the lithium-sulfur battery positive electrode material.

[0020] The present invention also provides a lithium-sulfur battery positive electrode material, wherein the positive electrode material is prepared by the method for preparing the lithium-sulfur battery positive electrode material as described in any one of the above items.

[0021] In summary, the present invention discloses a lithium-sulfur battery cathode material and its preparation method, comprising the steps of: adding asphalt and sulfur powder to an organic solvent, volatilizing the organic solvent to obtain a first precursor; mixing the first precursor with an absorbing material and grinding to obtain a second precursor; heating the second precursor in a microwave reactor under a protective atmosphere to obtain a third precursor; and ball-milling the third precursor to obtain the lithium-sulfur battery cathode material. The asphalt absorbs the sulfur powder, and the microwave reaction rapidly carbonizes the asphalt-sulfur powder composite material, thereby reducing sulfur loss and producing a lithium-sulfur battery cathode material with excellent electrochemical properties. The preparation method is simple, low-cost, and energy-efficient, making it suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The X-ray diffraction (XRD) diagram of the lithium-sulfur battery positive electrode material of the present invention is a flow chart of the preparation method of the lithium-sulfur battery positive electrode material.

[0023] Figure 2a This is a microwave heating curve in the preparation method of the lithium-sulfur battery positive electrode material of the present invention.

[0024] Figure 2b This is a thermogravimetric test diagram of the lithium-sulfur battery positive electrode material of the present invention.

[0025] Figure 2c This is the Raman spectrum of the lithium-sulfur battery positive electrode material of the present invention.

[0026] Figure 3 These are the field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM) images of the lithium-sulfur battery positive electrode material of the present invention.

[0027] Figure 4 The cyclic voltammetry curve of the lithium-sulfur battery assembled with the lithium-sulfur battery positive electrode material prepared in Example 1 of the present invention is shown.

[0028] Figure 5a This is a rate performance curve of a lithium-sulfur battery assembled using the lithium-sulfur battery positive electrode material prepared in Example 1 of the present invention.

[0029] Figure 5b The figure is a cycle performance curve of a lithium-sulfur battery assembled with the lithium-sulfur battery positive electrode material prepared in Example 1 of the present invention.

[0030] Figure 6 The present invention provides a flow chart of the method for preparing the positive electrode material for lithium-sulfur batteries. DETAILED DESCRIPTION

[0031] The present invention provides a lithium-sulfur battery cathode material and a method for preparing the same. To clarify the objectives, technical solutions, and advantages of the present invention, the present invention is described in further detail below. It should be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention.

[0032] Asphalt is rich in heteroatoms such as oxygen, nitrogen, and sulfur, resulting in excellent adsorption and catalytic properties for polysulfides. By combining asphalt with sulfur powder, asphalt can be easily adsorbed onto sulfur powder as a precursor for sulfur-carbon composites. However, due to sulfur's low boiling point of only 444°C, conventional carbonization processes are slow to heat up. For example, muffle furnaces and tube furnaces have a heating rate of only 20°C / minute. This results in sulfur volatilization during carbonization, resulting in a low sulfur content in the resulting sulfur-carbon composite. Using microwaves, however, allows for rapid carbonization of asphalt-sulfur powder composites, minimizing sulfur loss. Since both asphalt and sulfur powder are non-absorbent, carbon powder acts as an absorber, absorbing radiation and converting it into heat. The asphalt / sulfur powder composite, mixed with carbon powder and then heated in a microwave reactor, achieves rapid carbonization, resulting in a lithium-sulfur battery cathode material with excellent electrochemical properties. This simple, low-cost, and energy-efficient preparation method is amenable to industrial production.

[0033] Specifically, the present invention provides a method for preparing a positive electrode material for a lithium-sulfur battery, comprising the steps of:

[0034] S100, adding asphalt and sulfur powder into an organic solvent, and volatilizing the organic solvent to obtain a first precursor.

[0035] In specific implementation, since asphalt has low solubility in most solvents, the organic solvent needs to be selected from reagents with high solubility for asphalt, including toluene, xylene, chloroform, carbon disulfide, etc. In a specific embodiment, the step S100 specifically includes:

[0036] S110, dissolving asphalt in toluene, adding sulfur powder so that the asphalt is uniformly adsorbed on the surface of the sulfur powder, and volatilizing the toluene to obtain the first precursor.

[0037] In specific implementation, asphalt is first dissolved in toluene, and then sulfur powder is added to the toluene solution of asphalt. Since asphalt contains heteroatoms such as oxygen, nitrogen, and sulfur, it has strong polarity and can be easily adsorbed on the surface of sulfur powder. Therefore, a first precursor composed of asphalt and sulfur powder can be obtained by volatilizing the solvent.

[0038] In practice, a higher asphalt content improves the conductivity of the lithium-sulfur battery cathode material, thereby increasing sulfur utilization. The mass ratio of asphalt to sulfur powder in the present invention is 1:1.33-15. Optionally, the amount of asphalt used is 1-3g, and the amount of sulfur powder used is 4-15g. Maintaining the sulfur powder-to-asphalt mass ratio within the present invention's range ensures the charge storage performance and conductivity of the resulting lithium-sulfur battery cathode material.

[0039] In a specific implementation, to ensure that the asphalt is smoothly adsorbed on the surface of the sulfur powder, the concentration of the asphalt dissolved in the toluene is 0.1-1 g / mL. Optionally, the amount of the asphalt used is 1-3 g, and the amount of the toluene used is 3-10 mL.

[0040] In a specific implementation, the volatilization of the solvent includes rotary evaporation and vacuum evaporation. Alternatively, the asphalt is dissolved in toluene, sulfur powder is added so that the asphalt is uniformly adsorbed on the surface of the sulfur powder, and the toluene is evaporated from the mixture at 60°C to obtain the first precursor.

[0041] The method for preparing the positive electrode material of a lithium-sulfur battery according to the present invention further comprises the steps of:

[0042] S200: Mix the first precursor with an absorbing material, and grind to obtain a second precursor.

[0043] In specific implementation, the preparation method of the lithium-sulfur battery positive electrode material of the present invention needs to use the microwave heating reaction method to quickly heat up and carbonize the asphalt-sulfur powder composite material, so as to reduce the loss of sulfur. However, neither asphalt nor sulfur powder absorbs waves, so it is necessary to add an absorbing material to the first precursor, so that the absorbing material absorbs waves in the microwave reactor and converts them into heat to quickly carbonize the first precursor. Optionally, the absorbing material is carbon powder. Carbon powder has a strong ability to absorb waves and convert them into heat. Only a small amount of carbon powder is needed to quickly heat up and carbonize the asphalt. At the same time, the sulfur does not volatilize so quickly, thereby ensuring the electrochemical properties of the final lithium-sulfur battery positive electrode material. The grinding can be done by manual grinding or mechanical grinding. Optionally, the mixed powder is placed in a mortar and manually ground to obtain the second precursor. Optionally, the mixed powder is placed in a ball mill and ball-milled at a speed of 200-600rpm to obtain the second precursor. In a specific embodiment, the step S200 specifically includes:

[0044] S210 , mixing the first precursor with carbon powder, and grinding for 10 to 30 minutes to obtain the second precursor.

[0045] In a specific implementation, the first precursor is mixed with carbon powder and then manually ground in a mortar for 10 to 30 minutes to obtain the second precursor. Alternatively, the first precursor is mixed with carbon powder and then placed in a ball mill and ball milled at 400 rpm for 40 minutes to obtain the second precursor.

[0046] In a specific implementation, the mass ratio of the carbon powder to the first precursor is 1:(25-360). Optionally, when the amount of the asphalt is 1-3 g and the amount of the sulfur powder is 4-15 g, the amount of the carbon powder is 0.05-0.2 g.

[0047] Furthermore, the method for preparing the positive electrode material for lithium-sulfur batteries of the present invention further comprises the steps of:

[0048] S300, placing the second precursor in a microwave reactor under a protective atmosphere and performing microwave heating to obtain a third precursor.

[0049] In specific implementation, the protective atmosphere is a nitrogen atmosphere or an argon atmosphere. The second precursor is treated by microwave heating to achieve rapid temperature rise and carbonization. Due to the short microwave time and low microwave power, the heat treatment time can be greatly shortened, thereby saving energy and facilitating industrial application. Figure 2a The microwave heating curve of the microwave reaction in the preparation method of the lithium-sulfur battery positive electrode material according to the present invention is shown. As can be seen from the figure, the heating process takes approximately 100 seconds, during which the entire reaction system is heated to 650°C at a heating rate of approximately 350°C / min. The rapid heating rate and short heat treatment time can save energy and facilitate industrial application. In one embodiment, step S300 specifically includes:

[0050] S310, placing the second precursor in a microwave reactor under a nitrogen atmosphere for microwave heating, and reacting at 650° C. to obtain the third precursor.

[0051] In a specific implementation, the microwave power of the microwave heating in the microwave reactor is 300-500W, and the heating reaction time is 10-300s. The entire microwave reaction has low power and short duration, which can not only achieve rapid carbonization but also reduce energy consumption.

[0052] Furthermore, the method for preparing the positive electrode material for lithium-sulfur batteries of the present invention further comprises the steps of:

[0053] S400 , ball-milling the third precursor to obtain the lithium-sulfur battery positive electrode material.

[0054] In a specific implementation, step S400 specifically includes:

[0055] S410, ball milling the third precursor at a rotation speed of 200 to 600 rpm for 30 to 90 minutes to obtain the lithium-sulfur battery positive electrode material.

[0056] In a specific implementation, the third precursor is ball-milled at a rotation speed of 200 to 600 rpm for 30 to 90 minutes to obtain a sulfur-carbon composite material (S-SP@Bitu). Figure 1 The figure shows the XRD patterns of the sulfur-carbon composite material S-SP@Bitu and sulfur powder according to the present invention, wherein the X-ray diffractometer parameters are Rigaku-D / Max 2550, Cu-Kα, 40kV, 300mA, XRD phase contrast analysis shows that the sulfur-carbon composite material S-SP@Bitu is mainly sulfur peak, so there is a large amount of sulfur in it; Figure 2b The figure shows the thermogravimetric diagram of the sulfur-carbon composite material S-SP@Bitu of the present invention, wherein the heating rate of the thermogravimetric test is 10°C / min and the heating range is 30°C to 700°C. When the sulfur-carbon composite material S-SP@Bitu is heated, sulfur volatilizes due to heat, thereby causing the mass of the sulfur-carbon composite material S-SP@Bitu to change. It can be seen from the thermogravimetric diagram that the sulfur content in the sulfur-carbon composite material S-SP@Bitu is approximately 55%; Figure 2c The Raman spectrum of the sulfur-carbon composite material S-SP@Bitu of the present invention is shown. The light source of the Raman spectrometer is 622nm. It can be seen from the spectrum that the two Raman peaks indicate that the asphalt has been completely carbonized. Figure 1 、 Figure 2b and Figure 2c It can be seen that the sulfur-carbon composite material S-SP@Bitu prepared by the present invention not only achieves the carbonization of asphalt but also retains a large amount of sulfur. Therefore, using the sulfur-carbon composite material S-SP@Bitu as a positive electrode material for lithium-sulfur batteries can achieve excellent electrochemical performance, and the entire preparation process is simple, low-cost, and low-energy-consuming.

[0057] Further, if Figure 3Shown are the field emission scanning electron microscopy (FESEM, TESCAN MIRA3) and transmission electron microscopy (TEM, JEOL-2010, 200kV) characterization results of the sulfur-carbon composite material S-SP@Bitu of the present invention: Figures a and b are FESEM images, showing that the particle size of the sulfur-carbon composite material S-SP@Bitu is about 10μm; Figures c, d, e and f are TEM images, and energy spectrum analysis shows that the sulfur-carbon composite material S-SP@Bitu contains a large amount of sulfur, carbon, oxygen and nitrogen, and the multiple elements are evenly distributed. Therefore, the entire sulfur-carbon composite material S-SP@Bitu has high polarity and strong ability to adsorb and catalyze sulfur, thereby improving the overall electrochemical performance. Therefore, using the sulfur-carbon composite material S-SP@Bitu as a positive electrode material for lithium-sulfur batteries can achieve excellent electrochemical performance, and the entire preparation process is simple, low-cost and low-energy.

[0058] In some embodiments, the present invention further provides a lithium-sulfur battery positive electrode material, which is prepared using the preparation method described above.

[0059] The lithium-sulfur battery positive electrode material and preparation method of the present invention adsorb sulfur powder on asphalt, and then rapidly heat and carbonize the asphalt-sulfur powder composite material through microwave reaction, thereby reducing sulfur loss and obtaining a lithium-sulfur battery positive electrode material with good electrochemical performance. The preparation method is simple, low-cost, and low-energy-consuming, and is conducive to industrial production.

[0060] The application of an alkaloid in tobacco products and tobacco products of the present invention are further explained below through specific examples:

[0061] Example 1

[0062] Weigh 1 g of bitumen and dissolve it in 5 mL of toluene. Add 4 g of sulfur powder and stir thoroughly. Volatilize the toluene to obtain a first precursor, which is a brown-black powder.

[0063] Add 0.1 g of carbon powder (Super P) to the first precursor and grind it in a mortar to obtain a second precursor, which is a black powder;

[0064] The second precursor is treated under microwave conditions at 650° C. for 30 seconds with a microwave power of 390 W to obtain a third precursor, which is black block particles;

[0065] The third precursor was ball-milled at 600 rpm for 30 min to obtain the target lithium-sulfur battery positive electrode material (sulfur-carbon composite material S-SP@Bitu), which was a black powder.

[0066] Example 2

[0067] Weigh 1 g of asphalt and dissolve it in 10 mL of toluene. Add 15 g of sulfur powder and stir thoroughly. Volatilize the toluene to obtain a first precursor, which is a brown-black powder.

[0068] Add 0.15 g of carbon powder to the first precursor and grind it in a mortar to obtain a second precursor, wherein the second precursor is a black powder;

[0069] The second precursor is treated under microwave conditions at 650° C. for 100 s with a microwave power of 350 W to obtain a third precursor, which is black block-shaped particles;

[0070] The third precursor was ball-milled at 200 rpm for 90 min to obtain the target lithium-sulfur battery positive electrode material (sulfur-carbon composite material S-SP@Bitu), which was a black powder.

[0071] Example 3

[0072] 3 g of asphalt was weighed and dissolved in 3 mL of toluene, 4 g of sulfur powder was added and stirred thoroughly, and the toluene was evaporated to obtain a first precursor, which was a brown-black powder;

[0073] Add 0.1 g of carbon powder to the first precursor and grind it using a ball mill to obtain a second precursor, wherein the second precursor is a black powder;

[0074] The second precursor is treated under microwave conditions at 650° C. for 10 s with a microwave power of 500 W to obtain a third precursor, which is black block particles;

[0075] The third precursor was ball-milled at 400 rpm for 50 min to obtain the target lithium-sulfur battery positive electrode material (sulfur-carbon composite material S-SP@Bitu), which was a black powder.

[0076] Example 4

[0077] Weigh 1 g of asphalt and dissolve it in 4 mL of toluene. Add 4 g of sulfur powder and stir thoroughly. Volatilize the toluene to obtain a first precursor, which is a brown-black powder.

[0078] 0.2 g of carbon powder was added to the first precursor, and the mixture was ground using a ball mill to obtain a second precursor, wherein the second precursor was a black powder;

[0079] The second precursor is treated under microwave conditions at 650° C. for 200 s with a microwave power of 320 W to obtain a third precursor, which is black block particles;

[0080] The third precursor was ball-milled at 500 rpm for 30 min to obtain the target lithium-sulfur battery positive electrode material (sulfur-carbon composite material S-SP@Bitu), which was a black powder.

[0081] Example 5

[0082] 3 g of asphalt was weighed and dissolved in 9 mL of toluene, 15 g of sulfur powder was added and stirred thoroughly, and the toluene was evaporated to obtain a first precursor, which was a brown-black powder;

[0083] Add 0.05 g of carbon powder to the first precursor and grind it in a mortar to obtain a second precursor, wherein the second precursor is a black powder;

[0084] The second precursor is treated under microwave conditions at 650° C. for 300 s with a microwave power of 300 W to obtain a third precursor, which is black block particles;

[0085] The third precursor was ball-milled at 300 rpm for 60 min to obtain the target lithium-sulfur battery positive electrode material (sulfur-carbon composite material S-SP@Bitu), which was a black powder.

[0086] Furthermore, the lithium-sulfur battery cathode material of the present invention can be used to prepare a sulfur cathode with superior electrochemical performance, and the sulfur cathode can be assembled with a lithium anode to obtain a lithium-ion battery with excellent electrochemical performance. Specifically, the lithium-sulfur battery cathode material prepared in Examples 1 to 5 above, a conductive agent, and a binder are mixed in a mass ratio of 8:1:1 to form an electrode charge, wherein the conductive agent is conductive carbon black and the binder is polyvinylidene fluoride (PVDF). The electrode charge is coated on aluminum foil, dried at 60°C in a vacuum drying oven for 24 hours, and then punched into a circular sulfur cathode sheet with a diameter of 12 mm. In a glove box, the cathode sheet, separator, lithium metal sheet, and electrolyte (1M lithium bistrifluoromethanesulfonyl imide (LiTFSI) and 2wt% lithium nitrate (LiNO3) dissolved in a mixed solvent of ethylene glycol dimethyl ether (DME) and 1,3-dioxolane (DOL) in a volume ratio of 1:1) are assembled into a button cell.

[0087] Performance test: The lithium-sulfur battery cathode material prepared in Example 1 of the present invention was used to prepare a sulfur cathode according to the above method, and then assembled with a lithium metal anode material and an electrolyte to form a lithium-sulfur battery. The lithium-sulfur battery was then subjected to electrochemical performance tests and cycle performance tests. Figure 4 The cyclic voltammetry curve of the lithium-sulfur battery assembled with the lithium-sulfur battery positive electrode material prepared in Example 1 of the present invention is shown. Figure 4It can be seen from the above that the redox process of the lithium-sulfur battery is reversible. Figure 5a The figure shows the rate performance curve of the lithium-sulfur battery assembled with the lithium-sulfur battery positive electrode material prepared in Example 1 of the present invention. Figure 5b The graph shows the cycle performance of the lithium-sulfur battery assembled with the lithium-sulfur battery positive electrode material prepared in Example 1 of the present invention. Figure 5a and Figure 5b It can be seen that the lithium-sulfur battery assembled using the lithium-sulfur battery positive electrode material of the present invention has a high retention rate and strong recovery ability under different rate charge and discharge currents, and the capacity is relatively stable during constant current charge and discharge, that is, the lithium-sulfur battery assembled using the lithium-sulfur battery positive electrode material of the present invention has good electrochemical performance and stable use.

[0088] In summary, the present invention discloses a lithium-sulfur battery cathode material and its preparation method, comprising the steps of: adding asphalt and sulfur powder to an organic solvent, volatilizing the organic solvent to obtain a first precursor; mixing the first precursor with an absorbing material and grinding to obtain a second precursor; heating the second precursor in a microwave reactor under a protective atmosphere to obtain a third precursor; and ball-milling the third precursor to obtain the lithium-sulfur battery cathode material. The asphalt absorbs the sulfur powder, and the microwave reaction rapidly carbonizes the asphalt-sulfur powder composite material, thereby reducing sulfur loss and producing a lithium-sulfur battery cathode material with excellent electrochemical properties. The preparation method is simple, low-cost, and energy-efficient, making it suitable for industrial production.

[0089] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, they can make improvements or changes based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for preparing a positive electrode material for a lithium-sulfur battery, characterized in that: Including steps: adding asphalt and sulfur powder into an organic solvent, and volatilizing the organic solvent to obtain a first precursor; Mixing the first precursor with an absorbing material and grinding the mixture to obtain a second precursor; placing the second precursor in a microwave reactor under a protective atmosphere and performing microwave heating to obtain a third precursor; The microwave power of the microwave heating in the microwave reactor is 390W, and the reaction time is 30s; The mass ratio of the asphalt to the sulfur powder is 1:4; ball milling the third precursor to obtain the lithium-sulfur battery positive electrode material; The protective atmosphere is a nitrogen atmosphere, and the temperature of microwave heating in the microwave reactor is 650°C; Wherein, the absorbing material is carbon powder, and the mass ratio of the carbon powder to the first precursor is 1:(25~360).

2. The method for preparing a lithium-sulfur battery cathode material according to claim 1, wherein: The step of adding asphalt and sulfur powder to an organic solvent and volatilizing the organic solvent to obtain the first precursor specifically includes: dissolving asphalt in toluene, adding sulfur powder so that the asphalt is uniformly adsorbed on the surface of the sulfur powder, and volatilizing the toluene to obtain the first precursor.

3. The method for preparing a positive electrode material for a lithium-sulfur battery according to claim 2, wherein: The concentration of the asphalt dissolved in the toluene is 0.1-1 g / mL.

4. The method for preparing a lithium-sulfur battery cathode material according to claim 1, wherein: The mixing of the first precursor and the wave absorbing material and grinding to obtain the second precursor specifically includes: mixing the first precursor and the carbon powder, grinding for 10 to 30 minutes, to obtain the second precursor.

5. The method for preparing a lithium-sulfur battery cathode material according to claim 1, wherein: The step of ball milling the third precursor to obtain the lithium-sulfur battery positive electrode material specifically includes ball milling the third precursor at a rotation speed of 200-600 rpm for 30-90 minutes to obtain the lithium-sulfur battery positive electrode material.

6. A lithium-sulfur battery positive electrode material, characterized in that The lithium-sulfur battery positive electrode material is prepared by the preparation method of the lithium-sulfur battery positive electrode material according to any one of claims 1 to 5.

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