Carbon-supported metal nitride composite material, and preparation method and application thereof

Abstract

The application discloses a carbon-loaded metal nitride composite material and a preparation method and application thereof, and the carbon-loaded metal nitride composite material is mesoporous carbon nanotube-loaded ultra-small titanium nitride cluster. Aniline polymer is used as an anchoring and limited protection agent, so that the ultra-small titanium nitride nanocluster is in-situ grown on the ordered mesoporous carbon nanotube. The titanium nitride nanocluster has fully exposed surface active sites and high atomic utilization rate, has excellent adsorption and catalysis on polysulfides, and thus improves the performance of lithium-sulfur batteries. The mesoporous carbon nanotube-loaded titanium nitride cluster can be used for manufacturing a lithium-sulfur battery positive electrode. The material can greatly improve the conductivity of the positive electrode sheet, and to a certain extent, inhibits the polysulfide shuttle effect, promotes the catalytic conversion of sulfur, and has better specific capacity and stability than commercial conductive carbon black. The lithium-sulfur battery capacity is greatly improved, and the material is widely applied in the fields of electric vehicles, various spacecrafts and the like.

Description

Technical Field

[0001] This invention belongs to the field of new energy materials technology, specifically relating to a carbon-supported metal nitride composite material, its preparation method, and its application. Background Technology

[0002] Lithium-sulfur batteries are reactive batteries whose capacity contribution comes from the four-step redox reaction of sulfur, exhibiting an excellent theoretical specific capacity (1672 mAh·g). -1 ) and theoretical energy density (2600Wh·kg -1 Lithium-sulfur batteries have a conductivity 3 to 5 times higher than traditional lithium-ion batteries, and sulfur is widely available and environmentally friendly, making them a promising next-generation rechargeable battery. However, lithium-sulfur batteries still face many obstacles in their development. For example, sulfur and lithium sulfide are both insulators of electrons and ions (the electronic conductivity of sulfur at room temperature is approximately 10⁻³⁰ S·cm). -1 Therefore, its performance in terms of active material utilization, rate capability, and overpotential is not ideal. Furthermore, polysulfides (Li₂S₂) dissolved in the electrolyte... x (4≤x≤8) will shuttle between the anode and cathode, eventually forming insoluble Li2S2 / Li2S deposits on the lithium anode, leading to loss of active material and reduced battery performance.

[0003] To address the aforementioned issues in lithium-sulfur batteries, the common strategy for modifying cathode materials involves using carbon materials with good electronic and ionic conductivity to support sulfur, or loading polar materials onto a carbon matrix to enhance the chemisorption and catalytic conversion of polysulfides. However, the chemisorption and catalytic conversion of polysulfides by commonly used carbon materials loaded with metal carbides / oxides / nitrides are limited and cannot effectively improve the performance of lithium-sulfur batteries. Therefore, modifying the cathode materials of lithium-sulfur batteries to improve their catalytic performance remains a significant challenge. Summary of the Invention

[0004] To overcome the problems existing in the prior art, one objective of this invention is to provide a carbon-supported metal nitride composite material. A second objective is to provide a method for preparing the aforementioned carbon-supported metal nitride composite material. A third objective is to provide applications of the aforementioned carbon-supported metal nitride composite material. A fourth objective is to provide a lithium-sulfur battery.

[0005] Metal clusters possess well-exposed surface active sites and high atomic utilization, effectively promoting the adsorption and transformation of substances, and have attracted widespread attention in the field of electrocatalysis in recent years. This invention provides a method for supporting ultrasmall titanium nitride clusters on mesoporous carbon nanotubes, using aniline polymers as anchoring and confinement agents to enable the in-situ growth of ultrasmall TiN nanoclusters on ordered mesoporous carbon nanotubes.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] The first aspect of the present invention provides a carbon-supported metal nitride composite material, comprising mesoporous carbon nanotubes, wherein the surface of the mesoporous carbon nanotubes is loaded with highly graphitized mesoporous carbon and titanium nitride clusters.

[0008] Preferably, the raw material for the highly graphitized mesoporous carbon includes at least one of polyaniline and polydopamine.

[0009] Preferably, the size of the titanium nitride cluster is 0.5–3 nm.

[0010] A second aspect of the present invention provides a method for preparing the carbon-supported metal nitride composite material described in the first aspect, comprising the following steps:

[0011] S1. Disperse carbon nanotubes, soft templates, pore expanders, aniline compounds and titanium precursors in a solvent to obtain a mixed solution;

[0012] S2. Add ammonia water to the mixed solution to carry out the reaction and obtain the intermediate product;

[0013] S3. The intermediate product is calcined in an ammonia atmosphere to obtain a carbon-supported metal nitride composite material.

[0014] This invention uses a soft template method to prepare ordered mesoporous carbon nanotubes. In step S3, through a calcination reaction at 350°C, the soft template and pore expander volatilize, leaving an aniline polymer with a pore size of approximately 4 nm coated on the carbon nanotubes. Subsequently, highly graphitized carbon is formed at 800°C. Due to the removal of the soft template, a graphitized mesoporous carbon layer is finally formed on the carbon nanotubes. This method not only removes the template agent through heat treatment but also allows for nitriding reactions to produce titanium nitride clusters.

[0015] Preferably, the mass fractions of each raw material in step S1 are as follows: 50-100 parts carbon nanotubes, 800-1200 parts soft template, 1200-1600 parts aniline compounds, 3000-4000 parts pore expander, and 600-1000 parts titanium precursor.

[0016] Preferably, the solvent includes an alcohol-based solvent.

[0017] More preferably, the solvent is an ethanol-water solvent.

[0018] More preferably, the volume ratio of ethanol to water in the ethanol aqueous solvent is (0.7-1.5):1.

[0019] Preferably, the ratio of solvent to carbon nanotubes is 100 mL: (10-100) mg.

[0020] Preferably, the pore-expanding agent comprises at least one of polyethylene glycol, 1,3,5-trimethylbenzene, urea, decane, and hexamethylenetetramine;

[0021] 1,3,5-Trimethylbenzene, as a pore-expanding agent, can combine with the hydrophobic end of the soft template F127 to form stable spherical micelles, which plays a crucial role in the subsequent formation of ordered mesopores.

[0022] Preferably, the aniline compound includes at least one of aniline and dopamine;

[0023] Preferably, the soft template includes polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer, polystyrene-b-polyacrylic acid block copolymer, polystyrene-b-poly2-vinylpyridine block copolymer, and polymethyl methacrylate-b-polyoxyethylene block copolymer.

[0024] Preferably, the titanium precursor includes at least one of titanium tetrachloride and titanium isopropoxide.

[0025] Titanium tetrachloride and titanium isopropoxide are common titanium precursors that are readily available and can be anchored by carbon precursors. Furthermore, the titanium metal loading obtained by this method can reach 7 wt%, resulting in excellent dispersibility of titanium nitride clusters.

[0026] More preferably, titanium tetrachloride is prepared into an aqueous solution of carbon tetrachloride and then dispersed with other substances.

[0027] More preferably, the titanium precursor is added dropwise.

[0028] Preferably, in step S2, the ratio of ammonia to aniline compounds is (1-5) mL: 1 g.

[0029] Preferably, in step S2, the reaction is carried out under stirring conditions.

[0030] More preferably, the stirring rate is 400 to 1000 rpm.

[0031] Preferably, in step S2, the reaction time is 6 to 10 hours.

[0032] Preferably, step S2 further includes the following step: after the reaction is completed, the obtained intermediate product is dried at 50-70°C for 6-10 hours.

[0033] Preferably, in step S3, the calcination reaction temperature is 700–900°C and the reaction time is 1–4 h.

[0034] Preferably, in step S3, the atmosphere containing ammonia is an ammonia atmosphere, or a mixture of an ammonia atmosphere and other protective atmospheres; the protective atmosphere is nitrogen, an inert atmosphere, etc.

[0035] A third aspect of the invention provides the application of the carbon-supported metal nitride composite material described in the first aspect in electrode materials.

[0036] A fourth aspect of the present invention provides a lithium-sulfur battery comprising a positive electrode and a negative electrode, wherein the positive electrode comprises the carbon-supported metal nitride composite material described in the first aspect.

[0037] Preferably, the positive electrode includes a positive electrode material, a binder, a conductive agent, and a current collector; the positive electrode material includes a carbon-supported metal nitride composite material and sulfur powder.

[0038] More preferably, the cathode material is prepared by a method comprising the following steps: mixing the carbon-supported metal nitride composite material with sulfur powder and heating to obtain the cathode material.

[0039] The beneficial effects of this invention are:

[0040] This invention provides titanium nitride clusters supported on mesoporous carbon nanotubes, using aniline polymers as anchoring and confinement protective agents, enabling the in-situ growth of ultra-small titanium nitride (TiN) nanoclusters on ordered mesoporous carbon nanotubes. The TiN nanoclusters have fully exposed surface active sites and high atomic utilization, exhibiting excellent adsorption and catalytic effects on polysulfides, thereby improving the performance of lithium-sulfur batteries.

[0041] Specifically, compared with the prior art, the present invention has the following advantages:

[0042] 1. This invention provides mesoporous carbon nanotubes loaded with ultra-small titanium nitride clusters. The mesoporous carbon nanotubes (OMCNTs) have excellent electronic and ionic conductivity, which can significantly improve the conductivity and sulfur loading of the positive electrode active material sulfur. Titanium nitride itself has strong chemical polarity, which can adsorb polysulfides and thus suppress the shuttle effect to a certain extent. It also has a strong catalytic effect on the redox reaction of polysulfides. Further forming it into nanoclusters can greatly improve the adsorption and catalytic effect on polysulfides.

[0043] 2. This invention also provides a method for preparing ultra-small titanium nitride clusters supported on mesoporous carbon nanotubes. First, a solvent self-assembly method is used to ensure the uniform distribution of titanium and carbon precursors on the carbon nanotubes. Aniline compounds, as carbon precursors, play an anchoring role in the titanium precursor during the solution self-assembly process. Then, the aniline compounds undergo a polymerization reaction on the surface of the carbon nanotubes. During the high-temperature calcination process, the aniline polymer acts as an anchoring and confining protective agent for the titanium metal precursor, thereby limiting the aggregation, migration, and growth of titanium nitride, and thus enabling ultra-small TiN nanoclusters to grow in situ on ordered mesoporous carbon nanotubes.

[0044] 3. This invention also provides the application of mesoporous carbon nanotubes loaded with ultrasmall titanium nitride clusters as a cathode material. This material can greatly improve the conductivity of sulfur, the active material of the cathode, and to a certain extent suppress the polysulfide shuttle effect, promoting the catalytic conversion of sulfur. Its specific capacity and stability are superior to those of commercial conductive carbon black. Therefore, the mesoporous carbon nanotubes loaded with ultrasmall titanium nitride clusters prepared by this method can be used to manufacture the cathode of lithium-sulfur batteries, greatly improving the capacity of lithium-sulfur batteries, and can be widely used in electric vehicles, various spacecraft and other fields. Attached Figure Description

[0045] Figure 1 TEM image of OMCNT-TiN obtained in Example 1;

[0046] Figure 2 The TEM image shows the CNT-TiN prepared in Comparative Example 1.

[0047] Figure 3 The elemental energy spectrum analysis diagram of OMCNT-TiN prepared in Example 1 is shown below.

[0048] Figure 4 XPS image of OMCNT-TiN obtained in Example 1;

[0049] Figure 5 The image shows the XRD pattern of OMCNT-TiN obtained in Example 1.

[0050] Figure 6 The UV-Vis absorption spectra of Li2S6 adsorbed by OMCNT-TiN prepared in Example 1 and conductive carbon black in Comparative Example 2 are shown.

[0051] Figure 7 CV diagram of the OMCNT-TiN / S cathode material prepared in Example 1;

[0052] Figure 8 The constant potential discharge curves show the nucleation of Li2S on the OMCNT-TiN cathode material prepared in Example 1.

[0053] Figure 9Impedance diagrams of the OMCNT-TiN / S cathode material prepared in Example 1 and the commercial conductive carbon black in Comparative Example 2 are shown.

[0054] Figure 10 The rate performance graphs show the OMCNT-TiN / S cathode material prepared in Example 1 and the commercial conductive carbon black in Comparative Example 2.

[0055] Figure 11 Cyclic stability tests were conducted at 0.5C on the OMCNT-TiN / S cathode material prepared in Example 1 and the commercial conductive carbon black in Comparative Example 2.

[0056] Figure 12 This is a working diagram of a button cell fabricated using the OMCNT-TiN / S cathode material obtained in Example 1. Detailed Implementation

[0057] The present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the raw materials used in the following embodiments can be obtained from conventional commercial channels or prepared and isolated through simple synthesis; unless otherwise specified, the processes employed are conventional processes in the art.

[0058] Example 1

[0059] This embodiment provides mesoporous carbon nanotubes supporting ultrasmall titanium nitride clusters. The amounts of each raw material are shown in Table 1, and the preparation method is as follows:

[0060] S1: Carbon nanotubes, soft template agent F127 (polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer), 1,3,5-trimethylbenzene and dopamine are ultrasonically dispersed in an ethanol aqueous solution to obtain a mixed solution. Titanium isopropoxide is added dropwise to the mixed solution, and after ultrasonication, a uniform black mixed solution is formed.

[0061] S2: Add ammonia dropwise to the black mixed solution obtained in S1 to promote the polymerization reaction of carbon precursor, stir at 600 rpm for 8 hours, then centrifuge, and dry the intermediate product at 60°C for 8 hours.

[0062] S3: The intermediate product obtained in step 2 is calcined at 800°C for 2 hours under an ammonia atmosphere to obtain mesoporous carbon nanotube-supported ultrasmall titanium nitride clusters, denoted as OMCNT-TiN.

[0063] Examples 2-6

[0064] Examples 2-6 respectively provide mesoporous carbon nanotube-supported titanium nitride clusters, and the amounts of each raw material are shown in Table 1. The preparation methods are as in Example 1.

[0065] Comparative Example 1

[0066] Comparative Example 1 provides mesoporous carbon nanotubes loaded with titanium nitride. The amounts of each raw material are shown in Table 1. The difference from Example 1 is that dopamine is not added. The preparation method is the same as in Example 1. The product obtained is denoted as CNT-TiN.

[0067] Table 1. Raw material usage amounts for Examples 1-6 and Comparative Example 1

[0068]

[0069]

[0070] Comparative Example 2

[0071] Comparative Example 2 uses commercially available conductive carbon black cathode carrier material from Guangdong Candlelight New Energy Technology Co., Ltd., denoted as SP.

[0072] Material characterization

[0073] 1. TEM and particle size distribution statistics

[0074] The materials prepared in Example 1 and Comparative Example 1 were examined using transmission electron microscopy (TEM). Figure 1 TEM image of OMCNT-TiN obtained in Example 1; Figure 2 This is a TEM image of CNT-TiN prepared in Comparative Example 1. Figure 1 As can be seen, the OMCNT-TiN prepared by the method provided in Example 1 exhibits good dispersion of TiN nanoclusters, thus enabling better adsorption and catalytic effects of TiN nanoclusters on polysulfides and resulting in excellent battery performance. Furthermore, this method achieves in-situ growth of ultrasmall TiN nanoclusters on mesoporous carbon nanotubes, further demonstrating that the method achieves uniform anchoring and confinement of the titanium precursor, thereby preventing further cluster growth. Figure 2 It can be seen that in Comparative Example 1, without the addition of aniline compounds, the titanium nitride prepared could not form clusters and remained in the state of nanoparticles.

[0075] 2. Elemental energy dispersive spectroscopy analysis

[0076] The ultrasmall titanium nitride clusters supported on mesoporous carbon nanotubes prepared in Example 1 were detected using energy dispersive spectroscopy (EDS). Figure 3 This is the elemental energy dispersive spectroscopy (EDS) spectrum of the OMCNT-TiN catalyst prepared in Example 1. Figure 3 It can be seen that the OMCNT-TiN structure obtained by the preparation method provided in Example 1 is stable, the TiN is well dispersed, and it exhibits a relatively stable cluster state. This is due to the anchoring and confinement effect, which restricts the aggregation, migration and growth of TiN.

[0077] 3. X-ray photoelectron spectroscopy analysis

[0078] X-ray photoelectron spectroscopy was used to detect the ultrasmall titanium nitride clusters supported on mesoporous carbon nanotubes obtained in Example 1, wherein... Figure 4 The image shows the XPS plot of the OMCNT-TiN catalyst prepared in Example 1. Figure 4 It can be seen that the OMCNT-TiN prepared by the method provided in Example 1 has good matching with the characteristic peaks of TiN (Ti-N). This proves that the ultra-small titanium nitride clusters supported by the mesoporous carbon nanotubes have good chemical stability, and also clearly proves the specific existence state of Ti in OMCNT-TiN.

[0079] 4. XRD

[0080] The ultrasmall titanium nitride clusters supported on mesoporous carbon nanotubes prepared in Example 1 were analyzed using X-ray diffraction. Figure 5 The image shows the XRD pattern of OMCNT-TiN obtained in Example 1. Figure 5 It can be seen that OMCNT-TiN has gentle and broad peaks at 36.9°, 42.6° and 62°, which indicates the successful synthesis of TiN clusters and also represents that the TiN clusters are small in size and relatively uniformly distributed.

[0081] 5. Ultraviolet-Visible Absorption Spectroscopy Analysis

[0082] To verify the adsorption of polysulfides by the ultrasmall titanium nitride clusters supported on mesoporous carbon nanotubes prepared in Example 1, a saturated 1 mM / L Li₂S₆ solution was prepared using a 1:1 DOL / DME mixed solvent as the electrolyte base and an appropriate amount of Li₂S₆ was added. Then, 10 mg of OMCNT-TiN was added to 2000 mL of the Li₂S₆ solution, and the mixture was ultrasonically dispersed for 5 minutes. Static adsorption was then performed in an argon-filled glove box, which served as the operating chamber for all procedures. After 24 hours of adsorption, the supernatant was placed in a cuvette and subjected to UV-Vis spectroscopy using a Lambda 750 spectrometer. Figure 6 As shown, the UV-Vis adsorption spectroscopy results indicate that, compared with the commercial conductive carbon black in Comparative Example 2, OMCNT-TiN has the weakest Li2S6 adsorption characteristic peak (≈260nm), proving that OMCNT-TiN has a strong adsorption capacity for Li2S6.

[0083] Experimental Analysis

[0084] 1. Preparation for electrochemical testing

[0085] Electrochemical studies were conducted on the ultrasmall titanium nitride clusters supported on mesoporous carbon nanotubes prepared in Example 1 using a coin cell (LIR 2032). A coin cell was assembled using a sulfur composite cathode (OMCNT-TiN / S:Super P:PVDF = 7:2:1), a lithium anode, electrolyte, and Celgard 2400 in a glove box filled with Ar and with extremely low concentrations of H2O and O2. To ensure compatibility between the sulfur cathode and the lithium anode, a DOL / DME formulation with relatively weak lithium-ion battery dissolution capability was selected as the solvent. Then, 1 mol / L LiTFSI was dissolved in a DOL / DME mixed solvent (volume ratio 1:1) as the electrolyte. The electrolyte volume for the entire cell was 50 mL (cathode diameter 9 mm, electrolyte to sulfur ratio 13.8 mL mg). -1 The average areal loading of each composite cathode is approximately 1.2 mg·cm³. -2 The sulfur concentration is approximately 75 wt%.

[0086] 2. CV testing

[0087] On the LAND CT2001A, constant potential charge-discharge (GCD) tests were performed on a lithium-sulfur battery with OMCNT-TiN / S as the cathode (scan range: 1.6-2.8V relative to Li / Li). + Based on the sulfur weight of the cathode, the specific capacity and current rate (1C = 1672 mAh·g) were determined. -1 ).like Figure 7 As shown, the lithium-sulfur battery with OMCNT-TiN / S as the cathode exhibits a relatively typical stepwise discharge process of S. The cathode peaks at 2.20–2.30 V and 1.80–2.05 V correspond to the reduction of S8 to higher-order LiPSs and further reduction to lower-order Li2S2 / Li2S, respectively. On the other hand, the broad anode peak is attributed to the oxidation of Li2S2 / Li2S to Li2S6 / S8 through the formation of intermediate LiPSs.

[0088] 3. Li2S nucleation experiment

[0089] First, the loading of the host material in the positive electrode is controlled to be 0.5-1 mg·cm³. -2 The battery was assembled using lithium foil as the negative electrode in the manner described above, but with a slight change in the electrolyte. 25 μL of a 0.3 mol / L Li₂S₈ solution (tetraethylene glycol dimethyl ether) was added to the positive electrode, and 25 μL of the aforementioned lithium-sulfur electrolyte was added dropwise to the separator near the negative electrode. Next, this paper uses a Wuhan Landian M340A precision battery tester to perform Li₂S nucleation tests on the assembled battery. The battery was first discharged at a constant current of 0.112 mA to 2.06 V. Then, a constant potential test was performed at 2.05 V. When the current was below 10... -5The test ends at time A. Figure 8 As shown, when the cathode support is OMCNT-TiN prepared in Example 1, a more obvious Li2S deposition phenomenon is observed, and the time to reach the maximum Li2S deposition current is shorter. This proves that the OMCNT-TiN / S cathode material prepared in Example 1 has a good catalytic effect on the Li2S deposition reaction.

[0090] 4. Impedance test

[0091] CV measurements were performed on OMCNT-TiN of Example 1 and SP of Comparative Example 2 using a CHI660D electrochemical workstation and a cutoff voltage of 1.6–2.8 V. Measurements were taken at a frequency of 0.1 Hz to 10 Hz. 5 Electrochemical impedance spectroscopy (EIS) data were obtained by applying a 5mV oscillating sinusoidal wave within a frequency range of kHz using a Princeton 1260A impedance analyzer. The ohmic resistance (Re) and charge transfer resistance (Rct) of the material were analyzed using EIS and equivalent circuitry, and the results are as follows: Figure 9 As shown, in the mid-to-high frequency region, when the positive electrode support material is OMCNT-TiN prepared in Example 1, the semi-circular diameter is small, indicating a low charge transfer impedance (Rct) and fast electron transport during battery operation. Furthermore, it exhibits a low ohmic resistance (Re) in the high-frequency region, indicating a low internal resistance of the electrode material in the electrolyte. These results demonstrate that OMCNT-TiN significantly improves charge transfer kinetics.

[0092] 5. Ratio Performance Test

[0093] The rate performance of lithium-sulfur batteries with OMCNT-TiN / S cathodes was tested at different current densities. Figure 10 As shown, the reversible discharge capacities at 0.1, 0.5, 1, 2, 3, 4, and 5C are 1245, 1090, 970, 861, 737, 651, and 544 mAh g, respectively. -1 High specific capacity at high discharge rates is crucial for lithium batteries to provide high energy and power levels. At 5C, the specific capacity can still be maintained at 544 mAh g / L. -1 Meanwhile, it exhibits significant reversibility at different current densities; when the current density is reduced from 5C to 0.1C, the discharge capacity can be largely recovered.

[0094] 6. Battery stability test

[0095] The cycle stability of a lithium-sulfur battery with OMCNT-TiN / S as the cathode was tested at 0.5C. Figure 11 As shown, it exhibits a high capacity of 1192 mAh·g. -1The initial discharge capacity was [not specified], and after 100 cycles, the OMCNT-TiN / S cathode exhibited excellent long-term cycling stability, maintaining 500 mAh·g at 0.5C. -1 With its high specific capacity and 99.96% coulombic efficiency, the corresponding capacity decay per cycle is only 0.058%.

[0096] 7. Diagram of button battery operation

[0097] In addition, a lamp-lighting experiment was demonstrated using a lithium-sulfur battery with OMCNT-TiN / S as the cathode, which was used to power an LED lamp, such as... Figure 11 As shown, lithium-sulfur batteries with OMCNT-TiN / S as the cathode can provide relatively stable power to LED lights for a relatively long time.

[0098] The above is an explanation using the product obtained in Example 1 as an example. The products obtained in Examples 1 to 6 were used for various characterizations, and the characterization results were basically the same.

[0099] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A carbon-supported metal nitride composite material, characterized in that, It includes mesoporous carbon nanotubes, the surface of which is loaded with highly graphitized mesoporous carbon and titanium nitride clusters.

2. The carbon-supported metal nitride composite material according to claim 1, characterized in that, The raw materials for the highly graphitized mesoporous carbon include at least one of polyaniline and polydopamine.

3. The carbon-supported metal nitride composite material according to claim 1, characterized in that, The size of the titanium nitride clusters is 0.5–3 nm.

4. The method for preparing the carbon-supported metal nitride composite material according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1. Disperse carbon nanotubes, soft templates, pore expanders, aniline compounds and titanium precursors in a solvent to obtain a mixed solution; S2. Add ammonia water to the mixed solution to carry out the reaction and obtain the intermediate product; S3. The intermediate product is calcined in an ammonia atmosphere to obtain a carbon-supported metal nitride composite material.

5. The method for preparing the carbon-supported metal nitride composite material according to claim 4, characterized in that, The mass fractions of each raw material in step S1 are as follows: 50-100 parts carbon nanotubes, 800-1200 parts soft template, 1200-1600 parts aniline compounds, 3000-4000 parts pore expander, and 600-1000 parts titanium precursor.

6. The method for preparing the carbon-supported metal nitride composite material according to claim 4, characterized in that, The titanium precursor includes at least one of titanium tetrachloride and titanium isopropoxide.

7. The method for preparing the carbon-supported metal nitride composite material according to claim 4, characterized in that, In step S2, the ratio of ammonia water to aniline compounds is (1-5) mL: 1 g.

8. The method for preparing the carbon-supported metal nitride composite material according to claim 4, characterized in that, In step S3, the calcination reaction temperature is 700–900°C, and the reaction time is 1–4 h.

9. The application of the carbon-supported metal nitride composite material according to any one of claims 1 to 3 in electrode materials.

10. A lithium-sulfur battery, characterized in that, It includes a positive electrode and a negative electrode, wherein the positive electrode includes the carbon-supported metal nitride composite material according to any one of claims 1 to 3.

Images