A MoS2 modified nitrogen-doped carbon nanosheet composite material and its preparation and application

Abstract

The present invention belongs to the technical field of lithium battery material preparation, and discloses a MoS2 modified nitrogen-doped carbon nanosheet composite material and its preparation and application. The method comprises the following steps: (1) adding an organic carbon source, a nitrogen source and a solvent into a mortar and grinding them fully to obtain a mixture; (2) calcining the mixture in a tubular furnace to obtain nitrogen-doped carbon nanosheets; (3) modifying the nitrogen-doped carbon nanosheets to obtain modified nitrogen-doped carbon; (4) adding the modified nitrogen-doped carbon nanosheets into a metal phase MoS2 precursor solution to obtain a suspension, and subjecting the suspension to magnetic stirring, hydrothermal treatment and vacuum drying to obtain a target composite material. The composite material will not be excessively aggregated, and the tubular arrangement structure is convenient for the infiltration of the electrolyte, which is beneficial to the full embedding and extraction of lithium ions, thereby improving the conductivity of the carbon material and ensuring that the nitrogen-doped carbon has a high coulombic efficiency as a negative electrode material for lithium batteries.

Description

Technical Field

[0001] The present invention belongs to the technical field related to lithium battery materials, and more specifically, relates to a MoS2 modified nitrogen-doped carbon nanosheet composite material, a preparation method thereof, and an application thereof. Background Art

[0002] Lithium-ion batteries (LIBs) have become the first choice for various energy storage devices due to their high energy conversion efficiency, no memory effect, good safety, environmental friendliness, etc. The lithium-ion battery market has developed very rapidly. With the rapid development of electronic technology and the information industry, lithium-ion batteries have been widely used in portable electronic devices such as mobile phones, laptop computers, digital video cameras, etc. In addition, the current focus of further research and development of lithium-ion batteries is concentrated on high-capacity and high-power power lithium-ion batteries and battery packs. Among them, the research and development of LIBs anode materials are the key and technical core of the development of lithium-ion batteries. Graphite anode material is the anode material that people first started to study and apply in the commercial production of lithium-ion batteries. Its theoretical specific capacity is only 372 mAh / g, which cannot meet the requirements of higher specific capacity batteries. In addition, the lithium intercalation potential of the graphite anode material is relatively low (0 - 0.25 V vs Li + / Li), and lithium dendrites are easily precipitated during overcharging, causing battery short circuit and affecting the safety performance of lithium batteries.

[0003] As a typical transition metal sulfide, the S-Mo-S layer spacing of MoS2 is allowing lithium ions to be intercalated between the layer spacings, and the lithium intercalation potential is between 0.3 - 1.8 V vs Li + / Li, and its safety performance is better than that of graphite anode materials. In addition, the theoretical specific capacity of MoS2 as an LIBs anode material (800 - 1000 mAh / g) is about 3 times that of the carbon material anode, which can greatly improve the energy density of LIBs. MoS2 has two crystal structures, namely semiconductor phase and metal phase. Metallic MoS2 can not only efficiently intercalate and deintercalate Li + ions, and its excellent electrical conductivity ensures that metallic MoS2 has a high Coulomb efficiency as an LIBs anode material. However, metallic MoS2 is a metastable phase, and its preparation and storage are difficult, and it is easy to transform from the metal phase to the 2H phase with poor electrical conductivity, greatly reducing its Coulomb efficiency as an LIBs anode material. In addition, after long-term intercalation and deintercalation of Li + ions, metallic MoS2 as an LIBs anode material is prone to cause MoS2 cracking and decomposition into Mo nanoparticles and LiS2 with poor electrical conductivity, ultimately resulting in a significant decrease in the Coulomb efficiency of metallic MoS2 as an LIBs anode material.

[0004] Therefore, how to more simply and reasonably design and prepare high-capacity, high-stability, and low-cost MoS2 negative electrode materials has become one of the technical problems that need to be urgently solved in this field. Summary of the invention

[0005] In view of the above defects or improvement needs of the prior art, the present invention provides a tubular metal phase MoS2 modified nitrogen-doped carbon nanosheet composite negative electrode material and its preparation method and application. By means of its key components and its electrochemical reaction kinetic mechanism, MoS2 phase regulation, nitrogen-doped carbon nanosheet and MoS2 micromorphology control and ratio regulation, a new tubular metal phase MoS2 modified nitrogen-doped carbon nanosheet composite negative electrode system is obtained. Compared with existing products, the metal phase MoS2 is arranged in a tubular shape and will not be excessively agglomerated, and the tubular metal phase MoS2 is easy to be infiltrated by the electrolyte, which is conducive to the rapid insertion and extraction of lithium ions. Nitrogen-doped carbon nanosheets improve the conductivity of carbon materials by element doping, ensuring that nitrogen-doped carbon has a high coulombic efficiency as a negative electrode material for LIBs. In addition, nitrogen-doped carbon nanosheets use cheap glucose and urea as carbon and nitrogen sources, which greatly reduces the preparation cost. The present invention combines tubular metal phase MoS2 and nitrogen-doped carbon nanosheets, which not only ensures that the tubular metal phase MoS2 modified nitrogen-doped carbon nanosheet composite negative electrode material has high specific capacity and high coulombic efficiency, but also ensures that the metal phase MoS2 has excellent stability, effectively inhibiting the metal phase MoS2 from cyclically embedding and de-embedding Li + Decomposition in process.

[0006] To achieve the above object, according to one aspect of the present invention, the present invention first provides a method for preparing a MoS2 modified nitrogen-doped carbon nanosheet composite material, the preparation method comprising the following steps:

[0007] (1) adding an organic carbon source, an organic nitrogen source and a solvent into a mortar and grinding them sufficiently to obtain a uniform mixture of the organic carbon source and the organic nitrogen source;

[0008] (2) calcining the mixture in a tube furnace to obtain nitrogen-doped carbon nanosheets;

[0009] (3) mixing nitrogen-doped carbon nanosheets, an aqueous solution containing an organic ammonium halide modifier and deionized water to obtain a suspension, magnetically stirring the suspension, then filtering, washing and drying the suspension to obtain modified nitrogen-doped carbon nanosheets;

[0010] (4) Adding the modified nitrogen-doped carbon nanosheets into a metal phase MoS2 precursor solution to obtain a suspension, subjecting the suspension to magnetic stirring, hydrothermal treatment and vacuum drying, thereby obtaining a tubularly arranged metal phase MoS2 modified nitrogen-doped carbon nanosheet composite material.

[0011] Further, the organic carbon source in step (1) is glucose, sucrose or citric acid, preferably glucose; the organic nitrogen source is urea, melamine, dicyandiamide, or polyaniline, preferably urea; the solvent is absolute ethanol or deionized water, preferably absolute ethanol.

[0012] Further, the ratio of glucose, urea and absolute ethanol in step (1) is (4 - 8 g):(3 - 10 g):(5 - 8 ml).

[0013] Further, the calcination temperature in step (2) is 650 - 700 °C, and the heating rate is 5 - 8 °C / minute.

[0014] Further, the organic ammonium halide modifier in step (3) is preferably poly(diallyldimethylammonium chloride) or cetyltrimethylammonium bromide or dodecyltrimethylammonium bromide, and the mass fraction of the organic ammonium halide modifier in its aqueous solution is 30 - 40%.

[0015] Further, the dosage ratio of nitrogen-doped carbon, organic ammonium chloride modifier and deionized water in step (3) is 1 - 1.5 g:2 - 3 ml:100 - 150 ml.

[0016] Further, the suspension in step (4) is ammonium molybdate tetrahydrate, thiourea, deionized water and modified nitrogen-doped carbon nanosheets with a dosage ratio of 2.5 - 3.5 g:2 - 3 g:60 - 80 ml:1 - 1.5 g; or ammonium tetrathiomolybdate, thiourea, deionized water and modified nitrogen-doped carbon nanosheets with a dosage ratio of 4.5 - 5.5 g:2 - 3 g:60 - 80 ml:1 - 1.5 g; the stirring time of the suspension is 0.5 - 2 hours.

[0017] Further, the temperature of the hydrothermal treatment of the suspension in step (4) is 170 - 220 °C, and the hydrothermal treatment time is 10 - 24 hours, obtaining an internal structure with a tubular arrangement.

[0018] According to another aspect of the present invention, the present invention also provides a composite anode material of tubular arrangement metal phase MoS2 modified nitrogen-doped carbon nanosheets prepared by the above preparation method.

[0019] According to another aspect of the present invention, the present invention also provides the application of the above composite anode material of tubular arrangement metal phase MoS2 modified nitrogen-doped carbon nanosheets in lithium batteries.

[0020] Further, in the above application, the composite anode material of tubular arrangement metal phase MoS2 modified nitrogen-doped carbon nanosheets, conductive agent, binder and deionized water are mixed evenly, and then the composite anode material of tubular arrangement metal phase MoS2 modified nitrogen-doped carbon nanosheets is coated onto the current collector copper foil by a tablet pressing process to obtain a negative electrode sheet.

[0021] Furthermore, the conductive agent is at least one of Ketjen black, Super P, acetylene black, carbon black, carbon fiber, and carbon nanotube; the binder is at least one of sodium alginate, polyacrylic acid, and polyvinylidene fluoride; wherein, the mass ratio of the tubular-arranged metal-phase MoS2 modified nitrogen-doped carbon nanosheet composite anode material, the conductive agent, and the binder is (0.6 - 0.8):(0.1 - 0.2):(0.1 - 0.2).

[0022] Generally speaking, compared with the prior art by the above technical solution conceived by the present invention, the tubular-arranged metal-phase MoS2 modified nitrogen-doped carbon nanosheet composite anode material and its preparation method and application provided by the present invention mainly have the following beneficial effects:

[0023] 1. In the tubular-arranged metal-phase MoS2 modified nitrogen-doped carbon nanosheet composite anode material prepared by the present invention, the MoS2 nanosheets are arranged in tubes, which can facilitate the infiltration of the electrolyte and avoid the aggregation of MoS2 nanosheets. And because the introduced nitrogen-doped carbon material can not only effectively inhibit the decomposition of the metal-phase MoS2 during the cyclic insertion and extraction of Li + process, but also has a high Coulomb efficiency and a high specific capacity. Therefore, while ensuring the stability of MoS2 nanosheets, the problem of low specific capacity of carbon as the anode material of LIBs and too low Li + insertion potential is solved.

[0024] 2. The present invention uses cheap glucose and urea as the carbon source and nitrogen source of the nitrogen-doped carbon nanosheet anode material, greatly reducing the preparation cost of nitrogen-doped carbon and enabling large-scale industrial production.

[0025] 3. By strictly controlling the temperature and time of the hydrothermal treatment, the tubular-arranged metal-phase MoS2 modified nitrogen-doped carbon nanosheet composite anode material prepared by the present invention can effectively ensure that MoS2 is in the metal phase. The metal-phase MoS2 has an octahedral structure and can achieve a high Coulomb efficiency as an electron transport channel.

[0026] 4. The present invention modifies the surface of the nitrogen-doped carbon nanosheets with an organic ammonium halide modifier to make their surfaces positively charged. The modified nitrogen-doped carbon nanosheet surfaces can effectively adsorb molybdate ions, ensuring the uniform and sufficient growth of metal-phase MoS2 nanosheets on the modified nitrogen-doped carbon nanosheet surfaces, and finally obtaining tubular-arranged metal-phase MoS2 modified nitrogen-doped carbon nanosheets with uniformly distributed metal-phase MoS2 nanosheets.

[0027] 5. The tubular-arranged metal-phase MoS2 modified nitrogen-doped carbon nanosheet composite anode material prepared by the present invention is one of the ideal anode materials for lithium batteries, having excellent cycle stability and high specific capacity. Description of the Drawings

[0028] Figure 1 It is a schematic flow chart of the preparation method and performance verification of the composite material of tubular-arranged metallic-phase MoS2 modified nitrogen-doped carbon nanosheets provided in Example 1 of the present invention;

[0029] Figure 2 It is an XRD pattern of the composite material of tubular-arranged metallic-phase MoS2 modified nitrogen-doped carbon nanosheets prepared in Example 1 of the present invention;

[0030] Figure 3 It is an SEM image and an energy spectrum diagram of the nitrogen-doped carbon nanosheets prepared in Example 1 of the present invention;

[0031] Figure 4 It is an SEM image and an energy spectrum diagram of the composite material of tubular-arranged metallic-phase MoS2 modified nitrogen-doped carbon nanosheets prepared in Example 1 of the present invention;

[0032] Figure 5 It is a room-temperature charge-discharge cycle test chart of the lithium battery negative electrode prepared from the composite negative electrode material of tubular-arranged metallic-phase MoS2 modified nitrogen-doped carbon nanosheets prepared in Example 1 of the present invention. Detailed implementation manners

[0033] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. 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 present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0034] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. 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 present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] The present invention obtains a novel composite negative electrode system of tubular-arranged metallic-phase MoS₂ modified nitrogen-doped carbon nanosheets by means of the key constituent components of the negative electrode material, its electrochemistry reaction kinetics mechanism, MoS₂ phase regulation, carbon material element doping, microstructure control of nitrogen-doped carbon nanosheets and MoS₂, and ratio regulation. Compared with existing products, the metallic-phase MoS₂ is arranged in tubes, without excessive agglomeration, and the tubular-arranged metallic-phase MoS₂ facilitates the infiltration of the electrolyte, which is conducive to the rapid insertion and extraction of lithium ions. The nitrogen-doped carbon nanosheets improve the conductivity of the carbon material through element doping, ensuring that the nitrogen-doped carbon has a high Coulombic efficiency as the negative electrode material for LIBs. In addition, the nitrogen-doped carbon nanosheets use inexpensive glucose and urea as the carbon source and nitrogen source, greatly reducing the preparation cost. The present invention combines the tubular-arranged metallic-phase MoS₂ and the nitrogen-doped carbon nanosheets, ensuring that the composite negative electrode material of tubular-arranged metallic-phase MoS₂ modified nitrogen-doped carbon nanosheets has a high specific capacity and high Coulombic efficiency, while also ensuring that the metallic-phase MoS₂ has excellent stability, effectively inhibiting the decomposition of the metallic-phase MoS₂ during the cyclic insertion and extraction of Li + ions. At the same time, the composite negative electrode system of tubular-arranged metallic-phase MoS₂ modified nitrogen-doped carbon nanosheets can be coated on the negative electrode current collector copper foil, with the advantages of simple operation, strong applicability, good stability, etc., and thus is one of the ideal negative electrode materials for constructing high-energy density secondary lithium batteries.

[0036] Please refer to Figure 1 , the present invention provides a preparation method of a composite negative electrode material of tubular-arranged metallic-phase MoS₂ modified nitrogen-doped carbon nanosheets, and the preparation method includes:

[0037] The preparation method mainly includes the following sub-steps: adding glucose, urea and absolute ethanol into a mortar and grinding them sufficiently to obtain a uniform mixture of glucose and urea; then calcining the mixture in a tube furnace to obtain a kind of nitrogen-doped carbon nanosheets; mixing nitrogen-doped carbon, an aqueous solution of polydiallyldimethylammonium chloride or cetyltrimethylammonium bromide or dodecyltrimethylammonium bromide and deionized water and magnetically stirring to obtain modified nitrogen-doped carbon nanosheets; mixing ammonium molybdate tetrahydrate, thiourea and deionized water or ammonium tetrathiomolybdate and deionized water and magnetically stirring to obtain a uniform precursor solution of metallic-phase MoS₂; mixing the modified nitrogen-doped carbon nanosheets and the precursor solution of metallic-phase MoS₂ and magnetically stirring to obtain a suspension, and then hydrothermally treating, filtering and washing, and vacuum drying the suspension to obtain the composite material of tubular-arranged metallic-phase MoS₂ modified nitrogen-doped carbon nanosheets. Among them, urea is used as the nitrogen source and glucose is used as the carbon source. The nitrogen-doped carbon nanosheets obtained by uniformly mixing and calcining the two have excellent conductivity, improving the Coulombic efficiency of it as the negative electrode material for LIBs. By doping nitrogen elements, the defect density of the carbon nanosheets is increased, and more defects are constructed in the carbon nanosheets, which is conducive to more Li +Embedding to improve its specific capacity. In addition, the surface of the nitrogen-doped carbon nanosheets is modified with poly(diallyldimethylammonium chloride) or cetyltrimethylammonium bromide or dodecyltrimethylammonium bromide to make its surface carry sufficient positive charges, which is conducive to the subsequent adsorption of molybdate ions by the modified nitrogen-doped carbon nanosheets in the metal-phase MoS2 precursor solution, ensuring the uniform growth of metal-phase MoS2 on the surface of the nitrogen-doped carbon nanosheets. Metal-phase MoS2 nanosheets are grown on the surface of the modified nitrogen-doped carbon nanosheets by hydrothermal method, which improves the stability of metal-phase MoS2 and inhibits the decomposition of metal-phase MoS2 during the charge-discharge cycle. At the same time, the composite of metal-phase MoS2 nanosheets and nitrogen-doped carbon nanosheets has a high specific capacity, effectively solving the problem of low specific capacity of carbon anode materials. In addition, the metal-phase MoS2 nanosheets are arranged in a tubular shape on the surface of the nitrogen-doped carbon nanosheets, ensuring the full contact and infiltration of the metal-phase MoS2 nanosheets with the electrolyte, which is conducive to the rapid insertion and extraction of Li + The rapid insertion and extraction of Li. The composite anode system of tubular-arranged metal-phase MoS2 modified nitrogen-doped carbon nanosheets can be coated on the negative electrode current collector copper foil, which has the advantages of simple operation, strong applicability, good stability, and low cost.

[0038] The preparation method mainly includes the following steps:

[0039] Step 1: Glucose, urea and absolute ethanol are ground thoroughly in a mortar to ensure the uniform mixing of glucose and urea, and then a uniform mixture of glucose and urea is obtained.

[0040] In some embodiments, glucose, urea and absolute ethanol are added to the mortar in a ratio of 4-8 g: 3-10 g: 5-8 ml and ground for 15-30 minutes to obtain a uniform mixture of glucose and urea.

[0041] Step 2: The uniform mixture of glucose and urea is calcined in a tubular furnace to obtain nitrogen-doped carbon nanosheets.

[0042] In some embodiments, the uniform mixture of glucose and urea is placed in an alumina boat, and then the boat is placed in a tubular furnace; an argon-hydrogen mixture with a volume ratio of 90-95: 5-10 is introduced into the tubular furnace for 15-20 minutes to evacuate the air in the tubular furnace; it is heated to 650-700 °C at a heating rate of 5-8 °C / minute and kept warm for 2-3 hours to obtain nitrogen-doped nanosheets.

[0043] Step 3: Nitrogen-doped carbon nanosheets, poly(diallyldimethylammonium chloride) water or cetyltrimethylammonium bromide or dodecyltrimethylammonium bromide solution and deionized water are mixed to obtain a suspension, and the current suspension is magnetically stirred, filtered and washed to obtain modified nitrogen-doped carbon.

[0044] In some embodiments, the mass fraction of the aqueous solution of polydiallyldimethylammonium chloride or cetyltrimethylammonium bromide or dodecyltrimethylammonium bromide is 35%; the dosage ratio of nitrogen-doped carbon, polydiallyldimethylammonium chloride or cetyltrimethylammonium bromide or dodecyltrimethylammonium bromide aqueous solution and deionized water is 1-1.5 g: 2-3 ml: 100-150 ml; the magnetic stirring time of the suspension is 2-3 hours; the dispersant used in the washing process is deionized water, and the number of washing times is 3-5 times.

[0045] Step 4: Add the modified nitrogen-doped carbon nanosheets into the metal-phase MoS2 precursor solution to obtain a suspension, and magnetically stir, hydrothermally treat and vacuum dry the current suspension in sequence, so as to obtain a composite material of tube-arranged metal-phase MoS2 modified nitrogen-doped carbon nanosheets.

[0046] Mix ammonium molybdate tetrahydrate, thiourea and deionized water or ammonium tetrathiomolybdate and deionized water, and magnetically stir to obtain a uniform metal-phase MoS2 precursor solution.

[0047] In some embodiments, mix ammonium molybdate tetrahydrate, thiourea and deionized water or ammonium tetrathiomolybdate and deionized water and magnetically stir for 0.5-2 hours to obtain a uniform metal-phase MoS2 precursor solution; then, add the modified nitrogen-doped carbon into the metal-phase MoS2 precursor solution to obtain a suspension, and the dosage ratio of ammonium molybdate tetrahydrate, thiourea, deionized water and the modified nitrogen-doped carbon is 2.5-3.5 g: 2-3 g: 60-80 ml: 1-1.5 g; or the dosage ratio of ammonium tetrathiomolybdate, deionized water and the modified nitrogen-doped carbon is 4.5-5.5 g: 60-80 ml: 1-1.5 g, and magnetically stir the suspension for 0.5-2 hours; then, hydrothermally treat the suspension at 170-220 °C for 12-24 hours; then vacuum dry at 60-80 °C to obtain a composite material of tube-arranged metal-phase MoS2 modified nitrogen-doped carbon nanosheets.

[0048] The obtained composite material of tubular-arrayed metallic-phase MoS₂ modified nitrogen-doped carbon nanosheets is used as the anode material for lithium batteries. Specifically: The prepared composite anode material of tubular-arrayed metallic-phase MoS₂ modified nitrogen-doped carbon nanosheets, conductive agent, binder and deionized water are mixed evenly, and then the composite anode material of tubular-arrayed metallic-phase MoS₂ modified nitrogen-doped carbon nanosheets is coated onto the current collector copper foil by pressing to obtain the anode electrode sheet. Among them, the conductive agent is at least one of Ketjen black, Super P, acetylene black, carbon black, carbon fiber, carbon nanotubes; the binder is at least one of sodium alginate, polyacrylic acid and polyvinylidene fluoride; the dosage ratio of the composite anode material of tubular-arrayed metallic-phase MoS₂ modified nitrogen-doped carbon nanosheets, conductive agent, binder and deionized water is 0.6 - 0.8 g : 0.1 - 0.2 g : 0.1 - 0.2 g : 5 - 12 ml.

[0049] The following are several specific embodiments to further elaborate on the present invention.

[0050] Example 1

[0051] Please refer to Figure 2 、 Figure 3 and Figure 4 In this example, the composite anode material of tubular-arrayed metallic-phase MoS₂ modified nitrogen-doped carbon nanosheets includes tubular-arrayed metallic-phase MoS₂ nanosheets and nitrogen-doped carbon nanosheets. Among them, the metallic-phase molybdenum sulfide precursor solution is composed of ammonium molybdate tetrahydrate, thiourea and deionized water; the mass ratio of metallic-phase MoS₂ to nitrogen-doped carbon in the composite anode material of tubular-arrayed metallic-phase MoS₂ modified nitrogen-doped carbon nanosheets is 2:1; the conductive agent and binder are Ketjen black and sodium alginate; the composite anode of tubular-arrayed metallic-phase MoS₂ modified nitrogen-doped carbon nanosheets is prepared by a pressing process.

[0052] The process operation steps of this example are as follows:

[0053] (1) Add 5 g of glucose, 5 g of urea and 6 mL of absolute ethanol into a mortar and grind for 30 minutes until the absolute ethanol completely volatilizes to obtain a homogeneous mixture of glucose and urea.

[0054] (2) Put the homogeneous mixture of glucose and urea into a boat, and then place the boat in a tube furnace; first, introduce an argon-hydrogen mixture with a volume ratio of argon to hydrogen of 90:10 into the tube furnace for 15 minutes, and then heat it to 670 °C at a heating rate of 5 °C / minute and keep it at this temperature for 1 hour to obtain nitrogen-doped carbon nanosheets.

[0055] (3) Mix the nitrogen-doped carbon nanosheets, aqueous solution of poly(diallyldimethylammonium chloride), and deionized water in a ratio of 1.5 g : 2 ml : 100 ml and stir magnetically for 2 hours, then perform suction filtration and washing with deionized water three times to obtain the modified nitrogen-doped carbon nanosheets. Among them, the mass fraction of the aqueous solution of poly(diallyldimethylammonium chloride) is 35%.

[0056] (4) Mix ammonium molybdate tetrahydrate, thiourea, and deionized water and stir magnetically for 2 hours to obtain a uniform metal-phase MoS2 precursor solution; then, add the modified nitrogen-doped carbon to the metal-phase MoS2 precursor solution to obtain a suspension. The dosage ratio of ammonium molybdate tetrahydrate, thiourea, deionized water, and the modified nitrogen-doped carbon is 3.5 g : 1.5 g : 80 ml : 1.5 g. Continuously stir this suspension magnetically for 1.5 hours; then, hydrothermally treat this suspension at 200 °C for 12 hours; then perform suction filtration and washing of the suspension with deionized water three times, and then vacuum dry at 60 °C to obtain a composite material of metal-phase MoS2-modified nitrogen-doped carbon nanosheets arranged in tubes.

[0057] (5) Mix the prepared composite anode material of metal-phase MoS2-modified nitrogen-doped carbon nanosheets arranged in tubes, Ketjen black, sodium alginate, and deionized water evenly, and then use pressing to coat the composite anode material of metal-phase MoS2-modified nitrogen-doped carbon nanosheets arranged in tubes onto the current collector copper foil to obtain an anode sheet. Among them, the dosage ratio of the composite anode material of metal-phase MoS2-modified nitrogen-doped carbon nanosheets arranged in tubes, Ketjen black, sodium alginate, and deionized water is 0.6 g : 0.2 g : 0.2 g : 10 ml.

[0058] Test the cycling performance of the composite anode material of metal-phase MoS2-modified nitrogen-doped carbon nanosheets arranged in tubes as the lithium battery anode in a Li / / composite anode material of metal-phase MoS2-modified nitrogen-doped carbon nanosheets arranged in tubes system. At room temperature, at a current density of 1000 mAh g -1 the specific capacity of the composite anode material of metal-phase MoS2-modified nitrogen-doped carbon nanosheets arranged in tubes system is 792 mAh g -1 , and after 100 charge-discharge cycles, the specific capacity is 814 mAh g -1 .

[0059] Example 2

[0060] The composite anode material of tubular-arranged metallic-phase MoS₂ modified nitrogen-doped carbon nanosheets in this embodiment includes tubular-arranged metallic-phase MoS₂ nanosheets and nitrogen-doped carbon nanosheets. Among them, the metallic-phase molybdenum sulfide precursor solution is composed of ammonium molybdate tetrahydrate, thiourea and deionized water; the mass ratio of metallic-phase MoS₂ to nitrogen-doped carbon in the composite anode material of tubular-arranged metallic-phase MoS₂ modified nitrogen-doped carbon nanosheets is 1.5:1; the conductive agent and binder are Ketjenblack and sodium alginate; the anode of the composite material of tubular-arranged metallic-phase MoS₂ modified nitrogen-doped carbon nanosheets is prepared by a tablet pressing process.

[0061] The process operation steps of this embodiment are as follows:

[0062] (1) Add 5 g of glucose, 6 g of urea and 6 mL of absolute ethanol into a mortar and grind for 30 minutes until the absolute ethanol completely volatilizes to obtain a uniform mixture of glucose and urea.

[0063] (2) Put the uniform mixture of glucose and urea into a boat, and then place the boat in a tube furnace; first, introduce an argon-hydrogen mixture with a volume ratio of argon to hydrogen of 90:10 into the tube furnace for 15 minutes, and then heat it to 670 °C at a heating rate of 5 °C per minute and keep it warm for 1 hour to obtain nitrogen-doped carbon nanosheets.

[0064] (3) Mix the nitrogen-doped carbon nanosheets, aqueous solution of poly(diallyldimethylammonium chloride) and deionized water in a ratio of 1.5 g: 2 ml: 100 ml and stir magnetically for 2 hours, and then perform suction filtration and washing 3 times with deionized water to obtain modified nitrogen-doped carbon nanosheets. Among them, the mass fraction of the aqueous solution of poly(diallyldimethylammonium chloride) is 35%.

[0065] (4) Mix ammonium molybdate tetrahydrate, thiourea and deionized water and stir magnetically for 2 hours to obtain a uniform metallic-phase MoS₂ precursor solution; then, add the modified nitrogen-doped carbon into the metallic-phase MoS₂ precursor solution to obtain a suspension. The dosage ratio of ammonium molybdate tetrahydrate, thiourea, deionized water and modified nitrogen-doped carbon is 3.5 g: 1.5 g: 80 ml: 2.25 g. Continue to stir this suspension magnetically for 1.5 hours; then, hydrothermally treat this suspension at 200 °C for 12 hours; then perform suction filtration and washing 3 times on the suspension with deionized water, and then vacuum dry it at 60 °C to obtain the composite material of tubular-arranged metallic-phase MoS₂ modified nitrogen-doped carbon nanosheets.

[0066] (5) The prepared tubular-arrayed metal-phase MoS₂ modified nitrogen-doped carbon nanosheet composite anode material, Ketjen black, sodium alginate, and deionized water were mixed evenly, and then the tubular-arrayed metal-phase MoS₂ modified nitrogen-doped carbon nanosheet composite anode material was coated onto the current collector copper foil by pressing to obtain the anode plate. Among them, the dosage ratio of the tubular-arrayed metal-phase MoS₂ modified nitrogen-doped carbon nanosheet composite anode material, Ketjen black, sodium alginate, and deionized water was 0.8 g: 0.1 g: 0.1 g: 10 ml.

[0067] The cyclic performance of the lithium battery anode assembled with the tubular-arrayed metal-phase MoS₂ modified nitrogen-doped carbon nanosheet composite anode material was tested. At room temperature, at a current density of 1000 mAh g -1 , the specific capacity of the tubular-arrayed metal-phase MoS₂ modified nitrogen-doped carbon nanosheet composite anode material system was 723 mAh g -1 . After 100 charge-discharge cycles, the specific capacity was 715 mAh g -1 .

[0068] Example 3

[0069] The tubular-arrayed metal-phase MoS₂ modified nitrogen-doped carbon nanosheet composite anode material in this example includes tubular-arrayed metal-phase MoS₂ nanosheets and nitrogen-doped carbon nanosheets. Among them, the metal-phase molybdenum sulfide precursor solution is composed of ammonium tetrathiomolybdate and deionized water; the mass ratio of metal-phase MoS₂ to nitrogen-doped carbon in the tubular-arrayed metal-phase MoS₂ modified nitrogen-doped carbon nanosheet composite anode material is 2:1; the conductive agent and binder are Ketjen black and sodium alginate; the tubular-arrayed metal-phase MoS₂ modified nitrogen-doped carbon nanosheet composite anode is prepared by a pressing process.

[0070] The process operation steps of this example are as follows:

[0071] (1) 5 g of glucose, 5 g of urea, and 6 mL of absolute ethanol were added to a mortar and ground for 30 minutes until the absolute ethanol completely evaporated to obtain a uniform mixture of glucose and urea.

[0072] (2) The uniform mixture of glucose and urea was placed in a boat, and then the boat was placed in a tube furnace; the tube furnace was first purged with an argon-hydrogen mixture with a volume ratio of argon to hydrogen of 90:10 for 15 minutes, and then heated to 670 °C at a heating rate of 5 °C per minute and held for 1 hour to obtain nitrogen-doped carbon nanosheets.

[0073] (3) Mix nitrogen-doped carbon nanosheets, aqueous solution of polydiallyldimethylammonium chloride, and deionized water in a ratio of 1.5 g: 2 ml: 100 ml and stir magnetically for 2 hours, then perform suction filtration and washing 3 times with deionized water to obtain modified nitrogen-doped carbon nanosheets. Among them, the mass fraction of the aqueous solution of polydiallyldimethylammonium chloride is 35%.

[0074] (4) Mix ammonium tetrathiomolybdate and deionized water and stir magnetically for 1.5 hours to obtain a uniform metal-phase MoS2 precursor solution; then, add the modified nitrogen-doped carbon to the metal-phase MoS2 precursor solution to obtain a suspension. The dosage ratio of ammonium tetrathiomolybdate, deionized water, and modified nitrogen-doped carbon is 4.5 g: 80 ml: 2.25 g. Continue to stir this suspension magnetically for 1.5 hours; then, hydrothermally treat this suspension at 200 °C for 24 hours; then perform suction filtration and washing 3 times on the suspension with deionized water, and then vacuum dry at 60 °C to obtain a composite material of metal-phase MoS2-modified nitrogen-doped carbon nanosheets arranged in tubes.

[0075] (5) Mix the prepared composite anode material of metal-phase MoS2-modified nitrogen-doped carbon nanosheets arranged in tubes, Ketjen black, sodium alginate, and deionized water evenly, and then use pressing to coat the composite anode material of metal-phase MoS2-modified nitrogen-doped carbon nanosheets arranged in tubes onto the current collector copper foil to obtain an anode plate. Among them, the dosage ratio of the composite anode material of metal-phase MoS2-modified nitrogen-doped carbon nanosheets arranged in tubes, Ketjen black, sodium alginate, and deionized water is 0.6 g: 0.2 g: 0.2 g: 10 ml.

[0076] Test the cycling performance of the composite anode of the lithium battery with the composite anode material of metal-phase MoS2-modified nitrogen-doped carbon nanosheets arranged in tubes assembled as Li / / metal-phase MoS2-modified nitrogen-doped carbon nanosheets arranged in tubes. At room temperature, at a current density of 1000 mAh g -1 the specific capacity of the composite anode material system of metal-phase MoS2-modified nitrogen-doped carbon nanosheets arranged in tubes is 783 mAh g -1 , and after 100 charge-discharge cycles, the specific capacity is 775 mAh g -1 .

[0077] Example 4

[0078] The composite anode material of tubular-arrayed metallic-phase MoS2 modified nitrogen-doped carbon nanosheets in this embodiment includes tubular-arrayed metallic-phase MoS2 nanosheets and nitrogen-doped carbon nanosheets. Among them, the metallic-phase molybdenum sulfide precursor solution is composed of ammonium molybdate tetrahydrate, thiourea and deionized water; the mass ratio of metallic-phase MoS2 to nitrogen-doped carbon in the composite anode material of tubular-arrayed metallic-phase MoS2 modified nitrogen-doped carbon nanosheets is 2:1; the conductive agent and binder are Super P and polyacrylic acid; the anode of the composite material of tubular-arrayed metallic-phase MoS2 modified nitrogen-doped carbon nanosheets is prepared by a tabletting process.

[0079] The process operation steps of this embodiment are as follows:

[0080] (1) Add 5 g of glucose, 5 g of urea and 6 mL of absolute ethanol into a mortar and grind for 30 minutes until the absolute ethanol completely volatilizes to obtain a homogeneous mixture of glucose and urea.

[0081] (2) Put the homogeneous mixture of glucose and urea into a boat, and then place the boat in a tube furnace; first, introduce an argon-hydrogen mixture with a volume ratio of argon to hydrogen of 90:10 into the tube furnace for 15 minutes, and then heat it to 670 °C at a heating rate of 5 °C / minute and keep it warm for 1 hour to obtain nitrogen-doped carbon nanosheets.

[0082] (3) Mix the nitrogen-doped carbon nanosheets, aqueous solution of poly(diallyldimethylammonium chloride) and deionized water in a ratio of 1.5 g: 2 ml: 100 ml and stir magnetically for 2 hours, and then perform suction filtration and washing with deionized water 3 times to obtain modified nitrogen-doped carbon nanosheets. Among them, the mass fraction of the aqueous solution of poly(diallyldimethylammonium chloride) is 35%.

[0083] (4) Mix ammonium tetrathiomolybdate and deionized water and stir magnetically for 1.5 hours to obtain a homogeneous metallic-phase MoS2 precursor solution; then, add the modified nitrogen-doped carbon into the metallic-phase MoS2 precursor solution to obtain a suspension. The dosage ratio of ammonium molybdate tetrahydrate, thiourea, deionized water and modified nitrogen-doped carbon is 3.5 g: 1.5 g: 80 ml: 1.5 g. Continue to stir this suspension magnetically for 1.5 hours; then, hydrothermally treat this suspension at 200 °C for 24 hours; then filter and wash the suspension with deionized water 3 times, and then vacuum dry it at 60 °C to obtain the composite material of tubular-arrayed metallic-phase MoS2 modified nitrogen-doped carbon nanosheets.

[0084] (5) The prepared composite anode material of tubular-arranged metallic-phase MoS₂ modified nitrogen-doped carbon nanosheets, Super P, polyacrylic acid, and deionized water are mixed evenly, and then the composite anode material of tubular-arranged metallic-phase MoS₂ modified nitrogen-doped carbon nanosheets is coated onto the current collector copper foil by pressing to obtain the anode plate. Among them, the dosage ratio of the composite anode material of tubular-arranged metallic-phase MoS₂ modified nitrogen-doped carbon nanosheets, Super P, polyacrylic acid, and deionized water is 0.6 g : 0.2 g : 0.2 g : 10 ml.

[0085] Test the cycling performance of the anode of a lithium battery assembled with the composite anode material of tubular-arranged metallic-phase MoS₂ modified nitrogen-doped carbon nanosheets. At room temperature, at a current density of 1000 mAh g -1 , the specific capacity of the composite anode material system of tubular-arranged metallic-phase MoS₂ modified nitrogen-doped carbon nanosheets is 792 mAh g -1 . After 100 charge-discharge cycles, the specific capacity is 786 mAh g -1 .

[0086] Example 5

[0087] The composite anode material of tubular-arranged metallic-phase MoS₂ modified nitrogen-doped carbon nanosheets in this example includes tubular-arranged metallic-phase MoS₂ nanosheets and nitrogen-doped carbon nanosheets. Among them, the metallic-phase molybdenum sulfide precursor solution is composed of ammonium molybdate tetrahydrate, thiourea, and deionized water; the mass ratio of metallic-phase MoS₂ to nitrogen-doped carbon in the composite anode material of tubular-arranged metallic-phase MoS₂ modified nitrogen-doped carbon nanosheets is 2 : 1; the conductive agent and the binder are acetylene black and polyvinylidene fluoride; the anode of the composite material of tubular-arranged metallic-phase MoS₂ modified nitrogen-doped carbon nanosheets is prepared by a pressing process.

[0088] The process operation steps of this example are as follows:

[0089] (1) Add 5 g of glucose, 5 g of urea, and 6 mL of absolute ethanol to a mortar and grind for 30 minutes until the absolute ethanol completely evaporates to obtain a homogeneous mixture of glucose and urea.

[0090] (2) Place the homogeneous mixture of glucose and urea in a boat, and then place the boat in a tube furnace; first, introduce an argon-hydrogen mixture with a volume ratio of argon to hydrogen of 90 : 10 into the tube furnace for 15 minutes, and then heat it to 670 °C at a heating rate of 5 °C per minute and keep it at this temperature for 1 hour to obtain nitrogen-doped carbon nanosheets.

[0091] (3) Mix the nitrogen-doped carbon nanosheets, aqueous solution of polydiallyldimethylammonium chloride, and deionized water in a ratio of 1.5 g : 2 ml : 100 ml and stir magnetically for 2 hours, then perform suction filtration and washing with deionized water 3 times to obtain modified nitrogen-doped carbon nanosheets. Among them, the mass fraction of the aqueous solution of polydiallyldimethylammonium chloride is 35%.

[0092] (4) Mix ammonium tetrathiomolybdate and deionized water and stir magnetically for 0.5 - 2 hours to obtain a uniform metal-phase MoS₂ precursor solution; then, add the modified nitrogen-doped carbon to the metal-phase MoS₂ precursor solution to obtain a suspension. The dosage ratio of ammonium molybdate tetrahydrate, thiourea, deionized water, and modified nitrogen-doped carbon is 3.5 g : 1.5 g : 80 ml : 1.5 g. Continue to stir this suspension magnetically for 1.5 hours; then, hydrothermally treat this suspension at 200 °C for 24 hours; then perform suction filtration and washing of the suspension with deionized water 3 times, and then vacuum dry at 60 °C to obtain a composite material of tubular-arranged metal-phase MoS₂-modified nitrogen-doped carbon nanosheets.

[0093] (5) Mix the prepared composite anode material of tubular-arranged metal-phase MoS₂-modified nitrogen-doped carbon nanosheets, acetylene black, polyvinylidene fluoride, and deionized water evenly, and then use pressing to coat the composite anode material of tubular-arranged metal-phase MoS₂-modified nitrogen-doped carbon nanosheets onto the current collector copper foil to obtain an anode plate. Among them, the dosage ratio of the composite anode material of tubular-arranged metal-phase MoS₂-modified nitrogen-doped carbon nanosheets, acetylene black, polyvinylidene fluoride, and deionized water is 0.8 g : 0.1 g : 0.1 g : 10 ml.

[0094] Test the cycling performance of the composite anode of the tubular-arranged metal-phase MoS₂-modified nitrogen-doped carbon nanosheets assembled into a Li / / tubular-arranged metal-phase MoS₂-modified nitrogen-doped carbon nanosheets lithium battery anode. At room temperature, the specific capacity of the composite anode material system of the tubular-arranged metal-phase MoS₂-modified nitrogen-doped carbon nanosheets is 783 mAh g -1 at a current density of 1000 mAh g -1 , and the specific capacity is 766 mAh g after 100 charge-discharge cycles. -1 .

[0095] Example 6

[0096] The composite anode material of tubular-arranged metallic-phase MoS2 modified nitrogen-doped carbon nanosheets in this embodiment includes tubular-arranged metallic-phase MoS2 nanosheets and nitrogen-doped carbon nanosheets. Among them, the metallic-phase molybdenum sulfide precursor solution is composed of ammonium molybdate tetrahydrate, thiourea and deionized water; the mass ratio of metallic-phase MoS2 to nitrogen-doped carbon in the composite anode material of tubular-arranged metallic-phase MoS2 modified nitrogen-doped carbon nanosheets is 2:1; the conductive agent and binder are Ketjenblack and sodium alginate; the anode of the composite material of tubular-arranged metallic-phase MoS2 modified nitrogen-doped carbon nanosheets is prepared by a tabletting process.

[0097] The process operation steps of this embodiment are as follows:

[0098] (1) Add 5 g of glucose, 5 g of urea and 6 mL of absolute ethanol into a mortar and grind for 30 minutes until the absolute ethanol completely volatilizes to obtain a homogeneous mixture of glucose and urea.

[0099] (2) Put the homogeneous mixture of glucose and urea into a boat, and then place the boat in a tube furnace; first, introduce an argon-hydrogen mixture with a volume ratio of argon to hydrogen of 95:5 into the tube furnace for 15 minutes, and then heat it to 670 °C at a heating rate of 5 °C per minute and keep it warm for 1 hour to obtain nitrogen-doped carbon nanosheets.

[0100] (3) Mix the nitrogen-doped carbon nanosheets, cetyltrimethylammonium bromide aqueous solution and deionized water in a ratio of 1.5 g: 2 ml: 100 ml and stir magnetically for 2 hours, and then perform suction filtration and washing with deionized water 3 times to obtain modified nitrogen-doped carbon nanosheets. Among them, the mass fraction of the cetyltrimethylammonium bromide aqueous solution is 35%.

[0101] (4) Mix ammonium molybdate tetrahydrate, thiourea and deionized water and stir magnetically for 2 hours to obtain a homogeneous metallic-phase MoS2 precursor solution; then, add the modified nitrogen-doped carbon to the metallic-phase MoS2 precursor solution to obtain a suspension. The dosage ratio of ammonium molybdate tetrahydrate, thiourea, deionized water and modified nitrogen-doped carbon is 3.5 g: 1.5 g: 80 ml: 1.5 g. Continue to stir this suspension magnetically for 1.5 hours; then, hydrothermally treat this suspension at 200 °C for 12 hours; then filter and wash the suspension with deionized water 3 times, and then vacuum dry at 60 °C to obtain the composite material of tubular-arranged metallic-phase MoS2 modified nitrogen-doped carbon nanosheets.

[0102] (5) Mix the prepared tubular-arrayed metal-phase MoS₂ modified nitrogen-doped carbon nanosheet composite anode material, Ketjen black, sodium alginate, and deionized water evenly, and then use pressing to coat the tubular-arrayed metal-phase MoS₂ modified nitrogen-doped carbon nanosheet composite anode material onto the current collector copper foil to obtain the anode electrode sheet. Among them, the dosage ratio of the tubular-arrayed metal-phase MoS₂ modified nitrogen-doped carbon nanosheet composite anode material, Ketjen black, sodium alginate, and deionized water is 0.8 g: 0.1 g: 0.1 g: 10 ml.

[0103] Test the cycling performance of the anode of a lithium battery assembled with the tubular-arrayed metal-phase MoS₂ modified nitrogen-doped carbon nanosheet composite anode material. At room temperature, at a current density of 1000 mAh g -1 , the specific capacity of the tubular-arrayed metal-phase MoS₂ modified nitrogen-doped carbon nanosheet composite anode material system is 788 mAh g -1 . After 100 charge-discharge cycles, the specific capacity is 786 mAh g -1 .

[0104] Comparative Example 1

[0105] In this comparative example, the metal-phase MoS₂ precursor solution is composed of ammonium molybdate tetrahydrate, thiourea, and deionized water; the conductive agent and the binder are Ketjen black and sodium alginate; the tubular-arrayed metal-phase MoS₂ nanosheet material anode is prepared by a pressing process.

[0106] The process operation steps of this comparative example are as follows:

[0107] (1) Mix ammonium molybdate tetrahydrate, thiourea, and deionized water and stir magnetically for 2 hours to obtain a uniform metal-phase MoS₂ precursor solution; the dosage ratio of ammonium molybdate tetrahydrate, thiourea, and deionized water is 3.5 g: 1.5 g: 80 ml. Continue to stir this suspension magnetically for 1.5 hours; then, hydrothermally treat this solution at 200 °C for 12 hours; then filter and wash the suspension with deionized water 3 times, and then vacuum dry at 60 °C to obtain tubular-arrayed metal-phase MoS₂ nanosheets.

[0108] (2) Mix the prepared tubular-arrayed MoS₂ nanosheet anode material, Ketjen black, sodium alginate, and deionized water evenly, and then use pressing to coat the tubular-arrayed metal-phase MoS₂ nanosheet anode material onto the current collector copper foil to obtain the anode electrode sheet. Among them, the dosage ratio of the tubular-arrayed metal-phase MoS₂ nanosheet anode material, Ketjen black, sodium alginate, and deionized water is 0.8 g: 0.1 g: 0.1 g: 10 ml.

[0109] Test the cycling performance of the lithium battery negative electrode assembled with the pure MoS2 nanosheet negative electrode material in a tubular arrangement, Li / / tubular arrangement of MoS2 nanosheets. At room temperature, at a current density of 1000 mAh g -1 the specific capacity of the negative electrode material system of the tubular arrangement of metallic MoS2 nanosheets is 853 mAh g -1 , and the specific capacity is only 422 mAh g after 100 charge-discharge cycles -1 .

[0110] Comparative Example 2

[0111] In this comparative example, the composite negative electrode material of metallic MoS2 modified carbon nanosheets includes metallic MoS2 nanosheets and carbon nanosheets. Among them, the precursor solution of metallic MoS2 is composed of ammonium molybdate tetrahydrate, thiourea and deionized water; the mass ratio of metallic MoS2 to carbon in the composite negative electrode material of metallic MoS2 modified carbon nanosheets is 2:1; the conductive agent and the binder are Ketjenblack and sodium alginate; the negative electrode of the petal-shaped metallic MoS2 modified carbon nanosheet composite material is prepared by a tablet pressing process.

[0112] The process operation steps of this comparative example are as follows:

[0113] (1) Put sucrose into a boat, and then place the boat in a tube furnace; first, introduce an argon-hydrogen mixture with a volume ratio of argon to hydrogen of 90:10 into the tube furnace for 15 minutes, and then heat it to 670 °C at a heating rate of 5 °C / minute and keep it warm for 1 hour to obtain carbon nanosheets.

[0114] (2) Mix ammonium molybdate tetrahydrate, thiourea and deionized water and stir magnetically for 2 hours to obtain a uniform precursor solution of metallic MoS2; then, add carbon nanosheets to the precursor solution of metallic MoS2 to obtain a suspension. The dosage ratio of ammonium molybdate tetrahydrate, thiourea, deionized water and carbon nanosheets is 3.1 g: 2.8 g: 80 ml: 1.5 g. Continue to stir this suspension magnetically for 1.5 hours; then, hydrothermally treat this suspension at 180 °C for 12 hours; then filter and wash the suspension with deionized water 3 times, and then vacuum dry it at 60 °C to obtain a petal-shaped arrangement of metallic MoS2 modified carbon nanosheet composite material.

[0115] (3) Mix the prepared petal-shaped arrangement of MoS2 modified carbon nanosheet composite negative electrode material, Ketjenblack, sodium alginate and deionized water evenly, and then use tablet pressing to coat the petal-shaped arrangement of metallic MoS2 modified carbon nanosheet composite negative electrode material on the current collector copper foil to obtain a negative electrode plate. Among them, the dosage ratio of the petal-shaped arrangement of metallic MoS2 modified carbon nanosheet composite negative electrode material, Ketjenblack, sodium alginate and deionized water is 0.8 g: 0.1 g: 0. g: 10 ml.

[0116] Test the cycling performance of the lithium battery negative electrode assembled with the composite negative electrode material of petal-shaped arranged MoS2 modified carbon nanosheets, i.e., Li / / the negative electrode of petal-shaped arranged MoS2 modified carbon nanosheets. At room temperature, the specific capacity of the composite negative electrode material system of petal-shaped arranged MoS2 modified carbon nanosheets is 635 mAh g -1 at a current density of. After 100 charge-discharge cycles, the specific capacity is only 542 mAh g -1 . -1 .

[0117] It is easy for those skilled in the art to understand that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. A preparation method of a MoS2 modified nitrogen-doped carbon nanosheet composite material, characterized in that, The following steps are involved: (1) adding an organic carbon source, an organic nitrogen source and a solvent into a mortar and grinding them sufficiently to obtain a uniform mixture of the organic carbon source and the organic nitrogen source; (2) calcining the mixture in a tube furnace to obtain nitrogen-doped carbon nanosheets; (3) mixing nitrogen-doped carbon nanosheets, an aqueous solution containing an organic ammonium halide modifier and deionized water to obtain a suspension, stirring the suspension, filtering, washing and drying, and thereby obtaining modified nitrogen-doped carbon nanosheets; the mass fraction of the organic ammonium halide modifier in the aqueous solution is 30-40%; the amount ratio of the nitrogen-doped carbon nanosheets, the organic ammonium halide modifier and the deionized water is (1 to 1.5 g): (2 to 3 ml): (100 to 150 ml); (4) adding the modified nitrogen-doped carbon nanosheets to a metal phase MoS2 precursor solution to obtain a suspension, stirring, hydrothermally treating and vacuum drying the suspension to obtain a tubularly arranged metal phase MoS2 modified nitrogen-doped carbon nanosheet composite material; the suspension is composed of ammonium molybdate tetrahydrate, thiourea, deionized water and modified nitrogen-doped carbon nanosheets in a dosage ratio of 2.5 ~ 3.5g: 2 ~ 3g: 60 ~ 80ml: 1 ~ 1.5g; Or the usage ratio is 4.5 ~ 5.5g: 2 ~ 3g: 60 ~ 80ml: 1 ~ 1.5g of ammonium tetrathiomolybdate, thiourea, deionized water and modified nitrogen-doped carbon nanosheets.

2. The preparation method according to claim 1, wherein In step (1), the organic carbon source is glucose, sucrose or citric acid; the organic nitrogen source is urea, melamine, dicyandiamide or polyaniline; and the solvent is anhydrous ethanol or deionized water.

3. The preparation method according to claim 2, characterized in that, The organic carbon source is glucose; the organic nitrogen source is urea; and the solvent is anhydrous ethanol.

4. The preparation method according to claim 3, characterized in that, Step (1) The ratio of glucose, urea and anhydrous ethanol is (4 ~ 8g): (3 ~ 10g): (5 ~ 8 ml).

5. The preparation method according to claim 1, characterized in that, The calcination temperature in step (2) is 650-700°C, and the heating rate is 5-8°C / min.

6. The preparation method according to claim 1, wherein The organic ammonium halide modifier in step (3) is polydiallyldimethylammonium chloride or hexadecyltrimethylammonium bromide or dodecyltrimethylammonium bromide.

7. The preparation method according to claim 1, characterized in that The stirring time of the suspension in step (4) is 0.5 to 2 hours.

8. The preparation method according to claim 1 or 7, characterized in that, The temperature of the hydrothermal treatment of the suspension in step (4) is 170 to 220° C., and the hydrothermal treatment time is 10 to 24 hours.

9. A MoS2 modified nitrogen-doped carbon nanosheet composite material prepared by the method according to any one of claims 1 to 8.

10. Use of the MoS2 modified nitrogen-doped carbon nanosheet composite material as claimed in claim 9 in a negative electrode of a lithium battery.

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