Method for preparing nitrogen and sulfur co-doped carbon materials from templates and their applications in lithium / sodium storage

Abstract

The present invention belongs to the fields of inorganic nanomaterials and energy storage technologies, relates to heteroatom-doped carbon materials, and particularly relates to a method for preparing nitrogen and sulfur co-doped carbon materials by using a self-template. The carbon source containing nitrogen and sulfur is calcined at a high temperature in an inert atmosphere, and after natural cooling, impurities are removed by pickling to obtain the product. The present invention does not require additional nitrogen and sulfur sources, the reaction conditions are simple, the raw materials required in the preparation process are cheap, easy to obtain, non-toxic and harmless, and have extremely broad application prospects. The synthesized nitrogen and sulfur co-doped material itself has a large degree of disorder and specific surface area, good conductivity, and the nitrogen and sulfur doping increases the interlayer spacing and provides more active sites, and finally exhibits excellent reversible specific capacity, rate performance and cycle performance. The nitrogen and sulfur co-doped carbon material prepared by the present invention exhibits excellent rate performance and long cycle life, and is applied to lithium / sodium storage, which is beneficial to meeting actual needs.

Description

Technical Field

[0001] The present invention belongs to the technical fields of inorganic nanomaterials and energy storage technology, relates to heteroatom-doped carbon materials, and particularly relates to a method for preparing nitrogen-sulfur co-doped carbon materials by using a self-template and their applications in lithium / sodium storage. Background Art

[0002] As an electrochemical energy storage device, lithium-ion batteries are widely used in various electronic products due to their high energy density, high voltage, and long cycle life. However, due to the limited lithium resources and the energy density of lithium-ion batteries, people have been committed to developing alternatives to lithium. Among them, sodium-ion batteries are highly anticipated because of the abundant natural resources and similar chemical properties to lithium. However, the sodium ion radius is much larger than the lithium ion radius, which causes large lattice distortions during the deintercalation / insertion of Na + process, resulting in relatively limited reversible capacity and slow Na + migration kinetics. Therefore, a core challenge in promoting the development of sodium-ion battery technology is to seek anode materials with fast kinetics and high sodium storage capacity.

[0003] Carbon materials have been widely studied due to their advantages such as low cost, good conductivity, and high thermal stability. However, their low theoretical capacity and rate performance limit their further application and development in energy storage devices. In recent years, heteroatom doping has been proven to be an effective strategy to improve their electrochemical performance. Among them, introducing nitrogen atoms can enhance the electronic conductivity, regulate the charge density distribution, improve the conductivity, and at the same time introduce more active sites and external defects, which is beneficial to improving the reactivity of the material; introducing sulfur atoms can increase the interlayer spacing of carbon materials and can serve as additional sodium storage sites, providing more pseudocapacitance contributions and further improving the sodium storage capacity.

[0004] Currently, the application research of nitrogen-sulfur co-doped carbon anode materials is relatively extensive, but there are still many key problems to be solved: First, the microstructure of traditional carbon anode materials is dense, which inhibits the conductivity of the anode materials and the rate performance of sodium-ion batteries; second, the sources of nitrogen and sulfur in nitrogen-sulfur doped carbon materials currently come from separate nitrogen sources and sulfur sources, and the preparation process is cumbersome, energy-consuming, costly, and environmentally unfriendly, which restricts the practical application of nitrogen-sulfur co-doped carbon anode materials.

[0005] Therefore, it is particularly important to find a heteroatom carbon material with a simple preparation method, high safety and environmental protection, and stable structure to improve the performance of lithium / sodium-ion batteries. Summary of the Invention

[0006] Aiming at the problems of cumbersome preparation methods of heteroatom-doped carbon materials, low reversible capacity as electrode materials, poor rate performance and cycling stability, the object of the present invention is to provide a preparation method of nitrogen and sulfur co-doped carbon materials.

[0007] Technical solution

[0008] A method for preparing nitrogen and sulfur co-doped carbon materials by a self-template method, comprising: calcining a nitrogen and sulfur-containing carbon source at high temperature in an inert atmosphere, and pickling and removing impurities after natural cooling to obtain the product.

[0009] In a preferred embodiment of the present invention, the nitrogen and sulfur-containing carbon source is indigo disulfonate sodium, 2-aminopyridine-5-sulfonic acid or indamine blue, etc., and indigo disulfonate sodium is preferably used.

[0010] In a preferred embodiment of the present invention, the inert atmosphere is argon or nitrogen.

[0011] In a preferred embodiment of the present invention, the high-temperature calcination is heating at 600-1000 °C for 2-5 h.

[0012] In a preferred embodiment of the present invention, for the pickling, it is washed with an inorganic acid solution; further, the inorganic acid solution is a hydrochloric acid solution or a sulfuric acid solution with a mass fraction of 30%.

[0013] In a preferred embodiment of the present invention, the equipment used for high-temperature calcination is a tube furnace or a box furnace, and the heating rate is 2-15 °C·min -1 .

[0014] The nitrogen and sulfur co-doped carbon materials prepared according to the method of the present invention are applied to lithium / sodium storage, but are not limited to the above fields.

[0015] The present invention provides a high-performance and long-life lithium-ion battery, comprising a positive electrode sheet, a negative electrode sheet, a separator, a gasket, a washer and an electrolyte. The positive electrode sheet is a lithium sheet, the negative electrode sheet is formed by coating a negative electrode slurry on a current collector, followed by drying and rolling, and the electrolyte is 1M LiPF 6 .

[0016] The present invention also provides a high-performance and long-life sodium-ion battery, comprising a positive electrode sheet, a negative electrode sheet, a separator, a gasket, a washer and an electrolyte. The positive electrode sheet is a sodium sheet, the negative electrode sheet is formed by coating a negative electrode slurry on a current collector, followed by drying and rolling, and the electrolyte is 1M NaClO 4 .

[0017] Further, the negative electrode slurry of the lithium / sodium ion battery is a negative electrode slurry obtained by coating a negative electrode active material, a conductive agent, a dispersant, and a binder on the surface of a copper sheet in a mass ratio of 8:1:1. Among them, the negative electrode active material is a nitrogen and sulfur co-doped carbon material; the conductive agent is Ketjenblack EC-600JD; the dispersant is N-methylpyrrolidone (NMP); the binder is an oily binder polyvinylidene fluoride (PVDF).

[0018] The nitrogen and sulfur co-doped carbon material prepared by the present invention has good application prospects in lithium / sodium ion batteries. When used as a negative electrode material in lithium ion batteries, at 0.1 A g -1 it reaches a reversible capacity of 1320.6 mAh g -1 , and at 10 A g -1 the capacity is 290.4 mAh g -1 . After 3000 cycles, at 10.0 A g -1 the capacity reaches 270.8 mAh g -1 . When used as a negative electrode material in sodium ion batteries, at 0.1 A g -1 it reaches a reversible capacity of 518.0 mAh g -1 , and at 10 A g -1 the capacity is 114.1 mAh g -1 . After 3000 cycles, at 2.5 A g -1 the capacity reaches 176.7 mAh g -1 . It shows excellent rate and cycle performance in both lithium / sodium ion batteries.

[0019] Beneficial Effects

[0020] The present invention does not require additional nitrogen and sulfur sources, the reaction conditions are simple, the raw materials required in the preparation process are cheap, easily available, non-toxic and harmless, and have extremely wide application prospects. The synthesized nitrogen and sulfur co-doped material itself has a large degree of disorder and specific surface area, good conductivity, and nitrogen and sulfur doping increases the interlayer spacing, providing more active sites, and finally shows excellent reversible specific capacity, rate performance and cycle performance. The nitrogen and sulfur co-doped carbon material prepared by the present invention shows excellent rate performance and long cycle life, and is applied to lithium / sodium storage, which is beneficial to meeting actual needs. Brief Description of the Drawings

[0021] Figure 1 . Scanning electron microscope picture (SEM) of the nitrogen and sulfur co-doped carbon material prepared in Example 1;

[0022] Figure 2 . Transmission electron microscope picture (TEM) of the nitrogen and sulfur co-doped carbon material prepared in Example 1;

[0023] Figure 3 . X-ray energy spectrum analysis (EDS) diagram of the nitrogen and sulfur co-doped carbon material prepared in Example 1;

[0024] Figure 4 . X-ray powder diffraction (XRD) diagram of the nitrogen and sulfur co-doped carbon material prepared in Example 1;

[0025] Figure 5 . Raman diagram of the nitrogen and sulfur co-doped carbon material prepared in Example 1;

[0026] Figure 6 . Rate performance curve of the nitrogen and sulfur co-doped carbon material prepared in Example 1 when used as the anode of a sodium-ion battery;

[0027] Figure 7 . Cycle performance curve of the nitrogen and sulfur co-doped carbon material prepared in Example 1 when used as the anode of a sodium-ion battery. Detailed implementation manners

[0028] The present invention will be described in detail below in conjunction with embodiments, so that those skilled in the art can better understand the present invention, but the present invention is not limited to the following embodiments.

[0029] Example 1

[0030] The carbon source, sodium indigo disulfonate, was carbonized in a horizontal tube furnace under an Ar atmosphere for 2 hours at a carbonization temperature of 600 °C. The product was treated with 1 M hydrochloric acid (30%) to remove impurities, and a nitrogen and sulfur co-doped carbon material was obtained. The sample was labeled as S / N-C-600@2h.

[0031] The prepared nitrogen and sulfur co-doped carbon material was characterized for its performance, and its microstructure is as shown in Figure 1 and Figure 2 .

[0032] The EDS of the prepared nitrogen and sulfur co-doped carbon material is as shown in Figure 3 . The results show that the nitrogen and sulfur co-doped carbon material sample contains nitrogen and sulfur elements and is uniformly distributed in the sample.

[0033] The XRD diagram of the prepared nitrogen and sulfur co-doped carbon material is as shown in Figure 4 . There are broad peaks at 24° and 44° respectively, indicating that it has an amorphous carbon structure.

[0034] The Raman diagram of the prepared nitrogen and sulfur co-doped carbon material is as shown in 5. The analysis results show that the D peak and the G peak are located at 1365 cm -1 and 1595 cm -1 .

[0035] The prepared nitrogen and sulfur co-doped carbon material, conductive agent, and binder were made into an electrode in a ratio of 8:1:1, assembled with a lithium sheet into a half-cell, and subjected to performance testing. At current densities of 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, and 10.0 A g -1 the specific capacities were 1320.6, 110.5, 950.2, 730.2, 586.2, 459.1, and 290.4 mA h g -1 respectively, and 3000 cycles were carried out at a current density of 10.0 A g -1 and the capacity could still reach 270.8 mA h g -1 .

[0036] The prepared nitrogen and sulfur co-doped carbon material, conductive agent, and binder were made into an electrode in a ratio of 8:1:1, assembled with a sodium sheet into a half-cell, and subjected to performance testing. At current densities of 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, and 10.0 A g -1 the specific capacities were 457.6, 386.8, 319.5, 275.4, 213.8, 164.3, and 114.1 mA h g -1 respectively, and 3000 cycles were carried out at a current density of 2.5 A g -1 and the capacity could still reach 176.7 mA h g -1 , showing excellent rate and cycling performance, as shown in Figure 6 and Figure 7 .

[0037] Example 2

[0038] The carbon source indigo disulfonate sodium was carbonized in a horizontal tube furnace for 5 hours under an Ar atmosphere at a carbonization temperature of 600 °C. The product was treated with 1 M hydrochloric acid (30%) to remove impurities, and a nitrogen and sulfur co-doped carbon material was obtained.

[0039] The prepared nitrogen and sulfur co-doped carbon material, conductive agent, and binder were made into an electrode in a ratio of 8:1:1, assembled with a lithium sheet into a half-cell, and subjected to performance testing. At current densities of 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, and 10.0 Ag -1 the specific capacities were 1000.5, 950.3, 753.8, 638.5, 490.3, 330.2, and 220.4 mA h g -1 respectively, and 3000 cycles were carried out at a current density of 10.0 A g -1 and the capacity could still reach 210.8 mA h g -1 .

[0040] The prepared nitrogen-sulfur co-doped carbon material, conductive agent, and binder were made into an electrode in a ratio of 8:1:1, and assembled with a sodium sheet into a half-cell for performance testing. At current densities of 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, and 10.0 A g -1 the specific capacities were 400.5, 320.7, 290.8, 243.2, 190.7, 164.3, and 107.4 mA h g -1 respectively, and 3000 cycles were carried out at a current density of 2.5 A g -1 and the capacity could still reach 160.5 mA h g -1 .

[0041] Example 3

[0042] The carbon source, indigo disulfonate sodium, was carbonized in a horizontal tube furnace under an Ar atmosphere for 2 hours at a carbonization temperature of 1000 °C. The product was treated with 1 M hydrochloric acid (30%) to remove impurities, and a nitrogen-sulfur co-doped carbon material was obtained.

[0043] The prepared nitrogen-sulfur co-doped carbon material, conductive agent, and binder were made into an electrode in a ratio of 8:1:1, and assembled with a lithium sheet into a half-cell for performance testing. At current densities of 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, and 10.0 A g -1 the specific capacities were 1000.5, 950.3, 753.8, 638.5, 490.3, 330.2, and 220.4 mA h g -1 respectively, and 3000 cycles were carried out at a current density of 10.0 A g -1 and the capacity could still reach 210.8 mA h g -1 .

[0044] The prepared nitrogen-sulfur co-doped carbon material, conductive agent, and binder were made into an electrode in a ratio of 8:1:1, and assembled with a sodium sheet into a half-cell for performance testing. At current densities of 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, and 10.0 A g -1 the specific capacities were 410.5, 350.5, 320.6, 250.8, 207.3, 180.4, and 120.2 mA h g -1 respectively, and 3000 cycles were carried out at a current density of 2.5 A g -1 and the capacity could still reach 170.7 mA h g -1 .

[0045] Example 4

[0046] The carbon source indigo disulfonate sodium was carbonized in an Ar atmosphere in a horizontal tube furnace for 5 hours at a carbonization temperature of 1000 °C. The product was treated with 1 M hydrochloric acid (30%) to remove impurities, and a nitrogen-sulfur co-doped carbon material was obtained.

[0047] The prepared nitrogen-sulfur co-doped carbon material, conductive agent, and binder were made into an electrode in a ratio of 8:1:1, assembled with a lithium sheet into a half-cell, and subjected to performance testing. At current densities of 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, and 10.0 Ag -1 the specific capacities were 1100.5, 987.3, 767.8, 639.5, 520.3, 420.7, and 320.4 mA h g -1 , respectively, and 3000 cycles were carried out at a current density of 10.0 A g -1 , and its capacity could still reach 300.9 mA h g -1 .

[0048] The prepared nitrogen-sulfur co-doped carbon material, conductive agent, and binder were made into an electrode in a ratio of 8:1:1, assembled with a sodium sheet into a half-cell, and subjected to performance testing. At current densities of 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, and 10.0 A g -1 the specific capacities were 440.7, 368.2, 315.7, 280.3, 215.9, 176.3, and 110.6 mA h g -1 , respectively, and 3000 cycles were carried out at a current density of 2.5 A g -1 , and its capacity could still reach 166.3 mA h g -1 .

[0049] Example 5

[0050] The carbon source 2-aminopyridine-5-sulfonic acid was carbonized in an Ar atmosphere in a horizontal tube furnace for 2 hours at a carbonization temperature of 600 °C. The product was treated with 1 M hydrochloric acid (30%) to remove impurities, and a nitrogen-sulfur co-doped carbon material was obtained.

[0051] The prepared nitrogen-sulfur co-doped carbon material, conductive agent, and binder were made into an electrode in a ratio of 8:1:1, assembled with a lithium sheet into a half-cell, and subjected to performance testing. At current densities of 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, and 10.0 A g -1 the specific capacities were 1133.5, 926.3, 784.8, 632.9, 543.7, 422.4, and 352.1 mA h g -1 , respectively, and 3000 cycles were carried out at a current density of 10.0 A g -1 , and its capacity could still reach 328.8 mA h g -1。

[0052] The prepared nitrogen and sulfur co-doped carbon material, conductive agent, and binder were made into an electrode in a ratio of 8:1:1, assembled with a sodium sheet into a half-cell, and subjected to performance testing. At current densities of 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, and 10.0 A g -1 the specific capacities were 468.2, 396.3, 319.4, 285.6, 214.7, 198.3, and 119.6 mA h g -1 respectively, and 3000 cycles were carried out at a current density of 2.5 A g -1 and its capacity could still reach 185.0 mA h g -1 。

[0053] Example 6

[0054] The carbon source 2-aminopyridine-5-sulfonic acid was carbonized in a horizontal tube furnace under an Ar atmosphere for 2 hours at a carbonization temperature of 1000 °C. The product was treated with 1 M hydrochloric acid (30%) to remove impurities, obtaining a nitrogen and sulfur co-doped carbon material.

[0055] The prepared nitrogen and sulfur co-doped carbon material, conductive agent, and binder were made into an electrode in a ratio of 8:1:1, assembled with a lithium sheet into a half-cell, and subjected to performance testing. At current densities of 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, and 10.0 Ag -1 the specific capacities were 1278.6, 1026.4, 873.5, 744.1, 631.8, 510.5, and 440.1 mA h g -1 respectively, and 3000 cycles were carried out at a current density of 10.0 A g -1 and its capacity could still reach 388.8 mA h g -1 。

[0056] The prepared nitrogen and sulfur co-doped carbon material, conductive agent, and binder were made into an electrode in a ratio of 8:1:1, assembled with a sodium sheet into a half-cell, and subjected to performance testing. At current densities of 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, and 10.0 A g -1 the specific capacities were 428.6, 336.9, 344.1, 265.2, 217.3, 188.5, and 121.7 mA h g -1 respectively, and 3000 cycles were carried out at a current density of 2.5 A g -1 and its capacity could still reach 195.4 mA h g -1 。

[0057] Example 7

[0058] The carbon source, Yian blue, was carbonized in an Ar atmosphere in a horizontal tube furnace for 2 hours at a carbonization temperature of 600 °C. The product was treated with 1 M hydrochloric acid (30%) to remove impurities, obtaining a nitrogen and sulfur co-doped carbon material.

[0059] The prepared nitrogen and sulfur co-doped carbon material, conductive agent, and binder were made into an electrode in a ratio of 8:1:1, and assembled with a lithium sheet into a half-cell for performance testing. At current densities of 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, and 10.0 A g -1 the specific capacities were 1054.3, 982.4, 832.5, 720.1, 592.8, 410.3, and 326.9 mA h g -1 respectively, and 3000 cycles were carried out at a current density of 10.0 A g -1 and its capacity could still reach 300.3 mA h g -1 .

[0060] The prepared nitrogen and sulfur co-doped carbon material, conductive agent, and binder were made into an electrode in a ratio of 8:1:1, and assembled with a sodium sheet into a half-cell for performance testing. At current densities of 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, and 10.0 A g -1 the specific capacities were 418.5, 338.1, 262.6, 225.8, 198.3, 150.2, and 111.7 mA h g -1 respectively, and 3000 cycles were carried out at a current density of 2.5 A g -1 and its capacity could still reach 175.3 mA h g -1 .

[0061] Example 8

[0062] The carbon source, Yian blue, was carbonized in an Ar atmosphere in a horizontal tube furnace for 2 hours at a carbonization temperature of 1000 °C. The product was treated with 1 M hydrochloric acid (30%) to remove impurities, obtaining a nitrogen and sulfur co-doped carbon material.

[0063] The prepared nitrogen and sulfur co-doped carbon material, conductive agent, and binder were made into an electrode in a ratio of 8:1:1, and assembled with a lithium sheet into a half-cell for performance testing. At current densities of 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, and 10.0 A g -1 the specific capacities were 1247.9, 1038.6, 953.7, 836.2, 758.0, 528.3, and 452.5 mA h g -1 respectively, and 3000 cycles were carried out at a current density of 10.0 A g -1 and its capacity could still reach 410.3 mA h g -1 .

[0064] The prepared nitrogen and sulfur co-doped carbon material, conductive agent, and binder were made into an electrode in a ratio of 8:1:1, and assembled with a sodium sheet into a half-cell for performance testing. At current densities of 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, and 10.0 A g -1 , the specific capacities were 437.4, 363.2, 312.5, 270.4, 232.6, 190.7, and 125.3 mA h g -1 , respectively. And at a current density of 2.5 A g -1 , 3000 cycles were carried out, and the capacity could still reach 200.4 mA h g -1 .

[0065] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the description of the present invention, or directly or indirectly applied in other related technical fields, shall be similarly included in the patent protection scope of the present invention.

Claims

1. A method for preparing nitrogen and sulfur co-doped carbon materials by using a self-template, characterized in that: The carbon source containing nitrogen and sulfur is calcined at high temperature in an inert atmosphere, and after natural cooling, it is pickled to remove impurities, thus obtaining the product. Among them, the carbon source containing nitrogen and sulfur is sodium indigodisulfonate, 2-aminopyridine-5-sulfonic acid or indamine blue; the high-temperature calcination is heating at 600-1000 °C for 2-5 h.

2. The method for preparing nitrogen and sulfur co-doped carbon materials by using a self-template according to claim 1, characterized in that: The carbon source containing nitrogen and sulfur is sodium indigodisulfonate.

3. The method for preparing nitrogen and sulfur co-doped carbon materials by using a self-template according to claim 1, characterized in that: The inert atmosphere is argon or nitrogen.

4. The method for preparing nitrogen and sulfur co-doped carbon materials by using a self-template according to claim 1, characterized in that: For the pickling, it is washed with an inorganic acid solution.

5. The method for preparing nitrogen and sulfur co-doped carbon materials by using a self-template according to claim 4, characterized in that: The inorganic acid solution is a hydrochloric acid solution or a sulfuric acid solution with a mass fraction of 30%.

6. The method for preparing nitrogen and sulfur co-doped carbon materials by using a self-template according to claim 1, characterized in that: The equipment used for high-temperature calcination is a tube furnace or a box furnace, and the heating rate is 2-15 °C·min −1 .

7. An application of the nitrogen and sulfur co-doped carbon material prepared by any one of the methods according to claims 1-6, characterized in that: It is applied to lithium / sodium storage.

8. The application of the nitrogen and sulfur co-doped carbon material according to claim 7, characterized in that: It is used as a negative electrode material in sodium / lithium ion batteries.

9. The application of the nitrogen and sulfur co-doped carbon material according to claim 8, characterized in that: The lithium-ion battery includes a positive electrode sheet, a negative electrode sheet, a separator, a gasket, a washer, and an electrolyte. Among them, the positive electrode sheet is a lithium sheet; the negative electrode sheet is formed by coating a negative electrode paste on a current collector and then drying and rolling; the electrolyte is 1 M LiPF 6 .

10. The application of the nitrogen and sulfur co-doped carbon material according to claim 9, characterized in that: The negative electrode slurry is coated on the surface of a copper sheet and is composed of a negative electrode active material, a conductive agent, a dispersant and a binder in a mass ratio of 8:1:

1. Among them, the negative electrode active material is the nitrogen and sulfur co-doped carbon material; the conductive agent is Ketjenblack EC-600JD; the dispersant is N-methylpyrrolidone; the binder is an oily binder polyvinylidene fluoride.

11. The application of the nitrogen and sulfur co-doped carbon material according to claim 8, characterized in that: The sodium-ion battery includes a positive electrode sheet, a negative electrode sheet, a separator, a gasket, a washer, and an electrolyte. Among them, the positive electrode sheet is a sodium sheet; the negative electrode sheet is formed by coating a negative electrode paste on a current collector and then drying and rolling; the electrolyte is 1 M NaClO 4 .

12. The application of the nitrogen and sulfur co-doped carbon material according to claim 10, characterized in that: The negative electrode slurry is coated on the surface of a copper sheet and is composed of a negative electrode active material, a conductive agent, a dispersant and a binder in a mass ratio of 8:1:

1. Among them, the negative electrode active material is the nitrogen and sulfur co-doped carbon material; the conductive agent is Ketjenblack EC-600JD; the dispersant is N-methylpyrrolidone; the binder is an oily binder polyvinylidene fluoride.

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