Method for preparing vulcanized polyacrylonitrile by adopting microwave sintering process and product

Abstract

The invention discloses a method for preparing vulcanized polyacrylonitrile by adopting a microwave sintering process, which is characterized by comprising the following steps of: 1, premixing sulfur and polyacrylonitrile according to the weight ratio of (3: 1)-(8: 1) to obtain a mixture; step 2, flatly laying the mixture into a sintering container made of a glass or ceramic material, and introducing inert gas into the sintering container for anti-oxidation protection; and 3, carrying out microwave sintering on the sintering container filled with the mixture for 5-10 minutes under the microwave power of 300-800W and the temperature range of 160-Celsius degrees, cooling to room temperature, and collecting the sintered vulcanized polyacrylonitrile. By adopting the microwave sintering technology, the energy consumption and the sintering time are obviously reduced, and the high purity and the uniformity of the vulcanized polyacrylonitrile (SPAN) product are ensured. The method has the advantages of simple process flow, low equipment cost, easy realization of industrial preparation, no emission of harmful gas in the reaction process, and meeting of the requirement of green manufacturing.

Description

Technical Field

[0001] The present invention relates to the field of manufacturing vulcanized polyacrylonitrile, and particularly to a method and product for preparing vulcanized polyacrylonitrile by using a microwave sintering process. Background Art

[0002] Vulcanized polyacrylonitrile (SPAN), as a key cathode material for lithium-sulfur batteries, has received extensive attention due to its excellent electrical conductivity and sulfur utilization rate.

[0003] In the prior art, the preparation methods of vulcanized polyacrylonitrile (SPAN) mostly use resistance furnaces or hot air furnaces for sintering. For example, in CN115332514B, sintering is carried out in a tube furnace at 300 - 900 °C for 12 hours.

[0004] There are problems such as high energy consumption, long sintering time, and poor product uniformity, making it difficult to meet the requirements of efficient large-scale production.

[0005] In addition, the prior art has high requirements for temperature and time control. If not careful, it is easy to cause over-sintering or incomplete reaction of the product.

[0006] Microwave sintering, as a new sintering technology, has the advantages of uniform heating, low energy consumption, and fast heating rate, which can significantly improve the production efficiency and product quality of vulcanized polyacrylonitrile (SPAN).

[0007] However, there is currently no public technology for preparing vulcanized polyacrylonitrile (SPAN) by using microwave sintering. Therefore, it is necessary to develop a new process to solve the deficiencies of sintering with resistance furnaces or hot air furnaces. Summary of the Invention

[0008] In order to overcome the above-mentioned defects of the prior art, the purpose of the present invention is to provide a method and product for preparing vulcanized polyacrylonitrile by using a microwave sintering process. The present invention significantly reduces the sintering temperature and sintering time by using the microwave sintering process while improving the production efficiency and product quality of vulcanized polyacrylonitrile (SPAN).

[0009] In order to achieve the purpose of the present invention, the technical solution adopted is:

[0010] A method for preparing vulcanized polyacrylonitrile by using a microwave sintering process, comprising:

[0011] The first step,

[0012] Pre-mix sulfur and polyacrylonitrile in a weight ratio of 3:1 - 8:1 to obtain a mixture;

[0013] The second step,

[0014] Spread the mixture evenly in a sintering container made of glass or ceramic, and introduce an inert gas into the sintering container for antioxidant protection;

[0015] The third step,

[0016] Microwave sinter the sintering container filled with the mixture for 1 - 2 minutes under a microwave power of 300W - 800W and a temperature range of 160°C to 200°C, then adjust the power and sinter at 350 - 500°C for 3 - 5 minutes.

[0017] Then cool to room temperature and collect the sintered sulfurized polyacrylonitrile.

[0018] In a preferred embodiment of the present invention, the sintering container made of glass or ceramic is a glass boat or a ceramic boat.

[0019] In a preferred embodiment of the present invention, the inert gas is nitrogen or argon.

[0020] A sulfurized polyacrylonitrile product, which is obtained by the above steps.

[0021] In a preferred embodiment of the present invention, the sulfur content of the sulfurized polyacrylonitrile product is 45 - 60%;

[0022] The specific capacitance is 1200 - 1300 Ah / g.

[0023] The beneficial effects of the present invention are as follows:

[0024] The microwave sintering technology significantly reduces energy consumption and sintering time, and ensures the high purity and uniformity of the sulfurized polyacrylonitrile (SPAN) product. The process flow is simple, the equipment cost is low, it is easy to realize industrial preparation, and there is no harmful gas emission during the reaction, meeting the requirements of green manufacturing. Brief Description of the Drawings

[0025] Figure 1 It is a flow chart of the present invention.

[0026] Figure 2 It is Chart 1 of the performance test results of the SPAN product of the present invention.

[0027] Figure 3 It is Chart 2 of the performance test results of the SPAN product of the present invention. Detailed Embodiments

[0028] To make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the scope of the present invention. In addition, in the following structures, the descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0029] Example 1:

[0030] Sulfur and polyacrylonitrile were mixed at a weight ratio of 6:1, spread out and loaded into a glass boat, and then argon was introduced for protection. Sintering was carried out for minutes at a microwave power of 500 W and a temperature of 350 °C. After cooling, a uniform sulfurized polyacrylonitrile (SPAN) product 1 was obtained, with a sulfur content of 50% and a specific capacitance of 1250 mAh / g.

[0031] Example 2:

[0032] Sulfur and polyacrylonitrile were mixed at a weight ratio of 7:1, spread out and loaded into a ceramic boat, and then nitrogen was introduced for protection. Sintering was carried out for 10 minutes at a microwave power of 600 W and a temperature of 400 °C. After cooling, a sulfurized polyacrylonitrile (SPAN) product 2 was obtained, with a sulfur content of 52.5% and a specific capacitance of 1280 mAh / g.

[0033] Comparative Example 1

[0034] The mixture of Example 1 was sintered using a conventional electric furnace with the temperature set at 300 °C and the sintering time of 120 minutes.

[0035] After cooling, a sulfurized polyacrylonitrile (SPAN) product 3 was obtained, with a sulfur content of 40.1% and a specific capacitance of 920 mAh / g.

[0036] The above shows and describes the basic principles, main features and advantages of the invention.

[0037] Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the claimed present invention. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. A method for preparing polyacrylonitrile sulfide by microwave sintering process, characterized in that: include: first step, Premixing sulfur and polyacrylonitrile at a weight ratio of 3:1-8:1 to obtain a mixture; Step 2: The mixed material is spread evenly in a sintering container made of glass or ceramic material, and an inert gas is introduced into the sintering container for anti-oxidation protection; Step 3. The sintering container containing the mixed material is subjected to microwave sintering at a microwave power of 300W-800W and a temperature range of 160 degrees Celsius to 200 degrees Celsius for 2-5 minutes, and then sintered at 350-450 degrees for 3-10 minutes. The sintered polyacrylonitrile was then cooled to room temperature and the sintered polyacrylonitrile was collected.

2. The method for preparing polyacrylonitrile sulfide by microwave sintering process according to claim 1, characterized in that: The sintering container made of glass or ceramic material is a closed glass boat or ceramic boat.

3. The method for preparing polyacrylonitrile sulfide by microwave sintering process according to claim 1, characterized in that: The inert gas is nitrogen or argon.

4. A sulphurized polyacrylonitrile product, characterized in that: The sulfide polyacrylonitrile product is obtained by the steps as described in any one of claims 1 to 3.

5. A sulfurized polyacrylonitrile product as claimed in claim 4, characterized in that: The sulfur content of the polyacrylonitrile vulcanized product is 45-60%; The specific capacitance is 1200-1300 Ah / g.

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