Composite negative electrode material based on titanium nitride skeleton and preparation method and application thereof

Abstract

The invention discloses a composite negative electrode material based on a titanium nitride skeleton and a preparation method and application thereof. The composite negative electrode material comprises a matrix skeleton, a capacity providing unit embedded in the matrix skeleton and a coating layer, the matrix framework is made of titanium nitride, and the capacity providing unit is one or two of nanoscale Sn and nanoscale Sb. The high hardness, high conductivity and chemical stability of titanium nitride are utilized to construct a three-dimensional conductive network, and the volume change of Sn / Sb active particles is effectively restrained; a matrix skeleton and a capacity providing unit are prepared at the same time, Sn and / or Sb nanoparticles of the capacity providing unit are confined in a Ti3N5 matrix skeleton, and the Sn and / or Sb nanoparticles of the capacity providing unit and the Ti3N5 matrix skeleton directly form a tight link, so that interconnection of electric power-ion channels can be formed; the lithium / sodium storage mechanism is optimized through the electron / ion synergistic effect among elements, and the comprehensive performance breakthrough of high capacity, long service life and fast charging is achieved.

Description

Technical Field

[0001] This invention relates to the field of electrochemical energy storage technology, specifically to a composite anode material based on a titanium nitride framework, its preparation method, and its application. Background Technology

[0002] Currently, commercial sodium-ion batteries generally use hard carbon as the anode material, but its theoretical specific capacity is low, making it difficult to meet the demand for high energy density. Metal anodes such as tin (Sn) and antimony (Sb) have high theoretical specific capacity, but they undergo huge volume expansion during charge and discharge, leading to electrode material pulverization and shedding, which in turn causes severe capacity decay and electrolyte decomposition, limiting their practical application.

[0003] While conventional carbon coating or oxide / sulfide composite strategies can partially alleviate volumetric stress, they have the following drawbacks: carbon materials lack rigidity and are still prone to structural failure after long-term cycling; oxides / sulfides have poor conductivity, affecting fast-charging capability; and the synergistic effect of multiple elements has not been fully explored. Summary of the Invention

[0004] This invention addresses the shortcomings of existing technologies by providing a composite anode material based on a titanium nitride framework, its preparation method, and its application. Utilizing the high hardness, high conductivity, and chemical stability of titanium nitride (Ti3N5), a three-dimensional conductive network is constructed to effectively constrain the volume change of Sn / Sb active particles. Simultaneously, the lithium / sodium storage mechanism is optimized through inter-element electronic / ionic synergistic effects, achieving a comprehensive performance breakthrough in high capacity, long lifespan, and fast charging.

[0005] To address the aforementioned technical problems, the first aspect of this invention provides a composite anode material based on a titanium nitride framework, comprising a matrix framework, a capacity-providing unit embedded in the matrix framework, and a coating layer; the matrix framework is made of titanium nitride, and the capacity-providing unit is one or both of nanoscale Sn and Sb.

[0006] This invention utilizes the high hardness, high conductivity, and chemical stability of titanium nitride to construct a three-dimensional conductive network as a matrix framework, providing mechanical support and electronic conduction channels. Sn / Sb nanoparticles serve as capacity-providing units, with a theoretical capacity greater than 700 mAh / g, contributing significantly to high capacity, maximizing the utilization rate of active materials, and reducing the magnitude of single-cycle volume changes. Confining the Sn / Sb nanoparticles within the pores of the matrix framework effectively constrains the volume changes of the Sn / Sb active particles. Simultaneously, the lithium / sodium storage mechanism is optimized through inter-element electronic / ionic synergistic interactions, achieving a comprehensive breakthrough in high capacity, long lifespan, and fast charging performance. Furthermore, the coating layer improves the quality of the SEI film, reduces electrolyte side reactions, and further enhances conductivity and interfacial stability.

[0007] Furthermore, the mass percentage of the matrix skeleton is 40-70%, the mass percentage of the capacity providing unit is 20-50%, and the mass percentage of the covering layer is 1-10%. Preferably, the mass percentage of the matrix skeleton is 45-70%, the mass percentage of the capacity providing unit is 20-45%, and the mass percentage of the covering layer is 1-10%.

[0008] Furthermore, the matrix framework is a three-dimensional porous structure with a pore size of 5-50 nm.

[0009] Furthermore, the coating layer is a carbon layer with a thickness of 2-5 nm.

[0010] The second aspect of this invention provides a method for preparing the composite anode material based on the titanium nitride framework described in the first aspect, comprising the following steps:

[0011] S1. Mix and dissolve TiO2, urea, and M salt to obtain a homogeneous solution; wherein M is Sn and / or Sb, and M salt is a chloride.

[0012] S2. Ammonia water is added dropwise to carry out ammoniation reaction, and the precursor precipitate is obtained after aging.

[0013] S3. The precursor precipitate is calcined in stages at 300-500℃, 500-600℃, 600-700℃, and 700-800℃, and then cooled to obtain Ti3N5@M;

[0014] S4. After coating a carbon layer on the surface of Ti3N5@M by glucose-assisted hydrothermal method, the composite anode material based on titanium nitride framework is obtained by ball milling and dispersion.

[0015] This invention simultaneously prepares the matrix framework and the capacity-providing unit. The capacity-providing unit Sn and / or Sb nanoparticles are confined within the Ti3N5 matrix framework, and the two form a tight link, which enables the interconnection of the electro-ion channel.

[0016] Furthermore, in S2, the pH of the ammoniation reaction is 8.5-9.5, and the temperature is 60-80°C. Preferably, the pH is adjusted by concentrated ammonia, and the temperature parameters are optimized to avoid local supersaturation leading to aggregation.

[0017] Furthermore, in S2, after aging for 1-3 hours, a precursor precipitate containing Ti / M is formed.

[0018] Furthermore, in S3, the segmented calcination specifically includes:

[0019] (1) Under an air or oxygen atmosphere, heat the material to 300-500℃ at a rate of 2±0.2℃ / min and keep it at that temperature to remove surface organic matter and adsorbed water, and to avoid interference from impurities in the subsequent reduction reaction; preferably, the holding time is 0.5-1.5h.

[0020] (2) Under a mixed atmosphere of hydrogen and nitrogen, the temperature is increased to 500-600℃ at a rate of 1.5±0.2℃ / min and held for treatment to reduce M salt to M, reduce TiO2 to suboxide, and activate the lattice to promote the subsequent nitriding reaction; preferably, the holding time is 0.5-1h.

[0021] (3) Under an ammonia atmosphere, the temperature is increased to 600-700℃ at a rate of 1±0.2℃ / min and held for a period of time to convert the titanium suboxide into Ti3N5, while inhibiting the oxidation of M particles and maintaining stability; preferably, the holding time is 2-4h.

[0022] (4) Under a mixed atmosphere of nitrogen and argon, the temperature is increased to 800-900℃ at a rate of 0.5±0.2℃ / min and held for a period of time to optimize the Ti3N5 lattice, reduce lattice distortion caused by thermal stress, and suppress M volatilization; preferably, the holding time is 1-3h.

[0023] Furthermore, in S3, the cooling rate is ≤5℃ / min. Slow cooling prevents the material from cracking due to thermal shrinkage.

[0024] Furthermore, in S4, the temperature of the hydrothermal method is 160-180℃ to ensure uniform coating without damaging the main structure;

[0025] And / or, the ball milling dispersion speed is 300-500 rpm, and the particle size D50 after ball milling is 80-150 nm.

[0026] The third aspect of this invention provides the application of the composite anode material based on the titanium nitride framework described in the first aspect in batteries.

[0027] The beneficial effects of this invention are:

[0028] This invention simultaneously prepares the matrix framework and the capacity-providing unit. The capacity-providing unit Sn and / or Sb nanoparticles are confined within the Ti3N5 matrix framework, and the two form a tight link, which enables the interconnection of the electro-ion channel.

[0029] This invention utilizes the high hardness, high conductivity, and chemical stability of titanium nitride to construct a three-dimensional conductive network as a matrix framework, providing mechanical support and electronic conduction channels. Sn / Sb nanoparticles are used as capacity-providing units, with a theoretical capacity greater than 700 mAh / g, contributing to high capacity, maximizing the utilization rate of active materials, and reducing the magnitude of single volume changes. By confining the Sn / Sb nanoparticles within the pores of the matrix framework, the volume changes of the Sn / Sb active particles are effectively constrained. At the same time, the lithium / sodium storage mechanism is optimized through inter-element electronic / ionic synergistic effects, achieving a comprehensive performance breakthrough in high capacity, long lifespan, and fast charging.

[0030] This invention improves the quality of the SEI film by using a carbon coating layer, reduces electrolyte side reactions, and further enhances conductivity and interface stability. Detailed Implementation

[0031] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] This embodiment relates to a composite anode material based on a titanium nitride framework, comprising a matrix framework, capacity-providing units embedded in the matrix framework, and a coating layer. The matrix framework is made of titanium nitride, and the capacity-providing units are one or both of nanoscale Sn and Sb. This embodiment utilizes the high hardness, high conductivity, and chemical stability of titanium nitride to construct a three-dimensional conductive network as the matrix framework, providing mechanical support and electronic conduction channels. Sn / Sb nanoparticles are used as capacity-providing units, with a theoretical capacity greater than 700 mAh / g, contributing to high capacity, maximizing the utilization rate of active materials, and reducing the magnitude of single-cycle volume change. Confining the Sn / Sb nanoparticles within the pores of the matrix framework effectively constrains the volume change of the Sn / Sb active particles. Simultaneously, the lithium / sodium storage mechanism is optimized through inter-element electronic / ionic synergistic effects, achieving a comprehensive performance breakthrough in high capacity, long lifespan, and fast charging. Furthermore, the coating layer improves the SEI film quality, reduces electrolyte side reactions, and further enhances conductivity and interface stability.

[0033] In a preferred embodiment, the mass percentage of the matrix skeleton is 40-70%, the mass percentage of the capacity providing unit is 20-50%, and the mass percentage of the coating layer is 1-10%; the matrix skeleton is a three-dimensional porous structure with a pore size of 5-50 nm; and the coating layer is a carbon layer with a thickness of 2-5 nm.

[0034] Another embodiment relates to a method for preparing the composite anode material based on the titanium nitride framework described in the above embodiments, comprising the following steps:

[0035] S1. Mix and dissolve TiO2, urea, and M salt to obtain a homogeneous solution; wherein M is Sn and / or Sb, and M salt is a chloride.

[0036] S2. Ammonia water is added dropwise to carry out ammoniation reaction, and the precursor precipitate is obtained after aging.

[0037] S3. The precursor precipitate is calcined in stages at 300-500℃, 500-600℃, 600-700℃, and 700-800℃, and then cooled to obtain Ti3N5@M;

[0038] S4. After coating a carbon layer on the surface of Ti3N5@M by glucose-assisted hydrothermal method, the composite anode material based on titanium nitride framework is obtained by ball milling and dispersion.

[0039] In this embodiment, the matrix framework and capacity-providing units are fabricated simultaneously. The capacity-providing units, Sn and / or Sb nanoparticles, are confined within the Ti3N5 matrix framework, and the two form a tight link, which enables the interconnection of the electro-ion channels.

[0040] In a preferred embodiment, in step S2, the pH of the ammoniation reaction is 8.5-9.5, and the temperature is 60-80°C. Preferably, the pH is adjusted using concentrated ammonia, and the temperature parameters are optimized to avoid localized supersaturation leading to agglomeration. The mixture is aged for 1-3 hours to form a Ti / M-containing precursor precipitate.

[0041] In a preferred embodiment, S3 specifically includes:

[0042] (1) Under an air or oxygen atmosphere, heat the material to 300-500℃ at a rate of 2±0.2℃ / min and keep it at that temperature to remove surface organic matter and adsorbed water, and to avoid interference from impurities in the subsequent reduction reaction; preferably, the holding time is 0.5-1.5h.

[0043] (2) Under a mixed atmosphere of hydrogen and nitrogen, the temperature is increased to 500-600℃ at a rate of 1.5±0.2℃ / min and held for treatment to reduce M salt to M, reduce TiO2 to suboxide, and activate the lattice to promote the subsequent nitriding reaction; preferably, the holding time is 0.5-1h.

[0044] (3) Under an ammonia atmosphere, the temperature is increased to 600-700℃ at a rate of 1±0.2℃ / min and held for a period of time to convert the titanium suboxide into Ti3N5, while inhibiting the oxidation of M particles and maintaining stability; preferably, the holding time is 2-4h.

[0045] (4) Under a mixed atmosphere of nitrogen and argon, the temperature is increased to 800-900℃ at a rate of 0.5±0.2℃ / min and held for a period of time to optimize the Ti3N5 lattice, reduce lattice distortion caused by thermal stress, and suppress M volatilization; preferably, the holding time is 1-3h.

[0046] In a preferred embodiment, in step S3, the cooling rate is ≤5°C / min. Slow cooling prevents the material from cracking due to thermal shrinkage.

[0047] In a preferred embodiment, in S4, the temperature of the hydrothermal method is 160-180℃ to ensure uniform coating without damaging the main structure; the rotation speed of the ball milling dispersion is 300-500 rpm, and the particle size D50 after ball milling is 80-150 nm.

[0048] Another embodiment provides the application of the composite anode material based on the titanium nitride framework described in the above embodiments in a battery.

[0049] Example 1

[0050] This embodiment relates to a method for preparing a composite anode material (Ti3N5@Sn carbon-coated composite material) based on a titanium nitride framework, wherein the mass ratio of the anode material is Ti3N5:Sn:C = 60:38:2. The preparation method includes the following steps:

[0051] S1. Dissolve TiO2 (AR grade), urea, and SnCl4·5H2O in a 1:1 volume ratio of ethanol / water to obtain a homogeneous solution.

[0052] S2. Add ammonia water to adjust the pH to 8.0, raise the temperature to 70℃, carry out the ammoniation reaction, and after aging for 2 hours, obtain the precursor precipitate.

[0053] S3. The precursor precipitate is calcined in stages:

[0054] (1) Under air atmosphere, heat to 400℃ at a rate of 2℃ / min and hold for 1h;

[0055] (2) Under a mixed atmosphere of hydrogen and nitrogen (hydrogen volume percentage 5%), the temperature was increased to 550℃ at a rate of 1.5℃ / min and held for 0.5h.

[0056] (3) Under an ammonia atmosphere, the temperature was increased to 650℃ at a rate of 1℃ / min and held for 3 hours;

[0057] (4) Under a mixed atmosphere of nitrogen and argon (nitrogen to argon volume ratio 80:20), heat to 800-900℃ at a rate of 0.5℃ / min and hold for 2 hours;

[0058] (5) Subsequently, the temperature was lowered to room temperature at a rate of ≤5℃ / min to obtain Ti3N5@Sn composite material.

[0059] S4. After coating a carbon layer onto the surface of Ti3N5@M using a glucose-assisted hydrothermal method, Ti3N5@Sn carbon-coated composite anode material was obtained by ball milling and dispersion. The hydrothermal temperature was 170℃ for 8 hours, the ball milling speed was 400 rpm, and the milling time was 5 hours. The particle size D50 after ball milling was measured to be 85.4 nm using a laser particle size analyzer.

[0060] Example 2

[0061] The difference between this embodiment and Embodiment 1 is that the raw material composition ratio is adjusted so that the mass ratio of the prepared negative electrode material is Ti3N5:Sn:C = 50:48:2, while other steps and parameters remain unchanged.

[0062] Example 3

[0063] The difference between this embodiment and Embodiment 1 is that the capacity-providing unit Sn is replaced with Sb to prepare Ti3N5@Sb carbon-coated composite material. The mass ratio of the anode material is Ti3N5:Sb:C = 60:38:2, while other steps and parameters remain unchanged.

[0064] Comparative Example 1

[0065] The difference between this comparative example and Example 1 is that Ti3N5 is not used to confine Sn. The specific preparation method is as follows:

[0066] Sn powder and graphene were mixed in a ratio of 98:2 and loaded into an argon-filled ball mill jar along with grinding balls. The mixture was then ball-milled at 400 rpm for 10 hours in a planetary ball mill. The mechanical force nano-sized the Sn particles and uniformly embedded them into the carbon matrix, forming a Sn-C composite anode material.

[0067] Comparative Example 2

[0068] The difference between this comparative example and Example 1 is that porous Ti3N5 is prepared first, and then Sn is filled in. Following the steps of Example 1, SnCl4·5H2O is not used in step S1; instead, Sn powder is added in step S4. The specific preparation method is as follows:

[0069] S1. Dissolve TiO2 (AR grade) and urea in a 1:1 volume ratio of ethanol / water mixed solvent to obtain a homogeneous solution.

[0070] S2. Add ammonia water to adjust the pH to 8.0, raise the temperature to 70℃, carry out the ammoniation reaction, and after aging for 2 hours, obtain the precursor precipitate.

[0071] S3. The precursor precipitate is calcined in stages:

[0072] (1) Under air atmosphere, heat to 400℃ at a rate of 2℃ / min and hold for 1h;

[0073] (2) Under a mixed atmosphere of hydrogen and nitrogen (hydrogen volume percentage 5%), the temperature was increased to 550℃ at a rate of 1.5℃ / min and held for 0.5h.

[0074] (3) Under an ammonia atmosphere, the temperature was increased to 650℃ at a rate of 1℃ / min and held for 3 hours;

[0075] (4) Under a mixed atmosphere of nitrogen and argon (nitrogen to argon volume ratio 80:20), heat to 800-900℃ at a rate of 0.5℃ / min and hold for 2 hours;

[0076] (5) Subsequently, the temperature was lowered to room temperature at a rate of ≤5℃ / min to obtain Ti3N5 material.

[0077] S4. Sn powder and Ti3N5 material were mixed in ethanol at a ratio of 38:60, dried, and then carbon-coated using a glucose-assisted hydrothermal method at 170℃ for 8 hours. The Ti3N5 / Sn carbon-coated composite anode material was obtained by ball milling at 400 rpm for 5 hours.

[0078] Comparative Example 3

[0079] The difference between this comparative example and Example 1 is that the raw material composition ratio was adjusted so that the mass ratio of the prepared negative electrode material was Ti3N5:Sn:C = 40:58:2, while other steps and parameters remained unchanged.

[0080] Application examples

[0081] Battery assembly:

[0082] Negative electrode sheet: The negative electrode materials obtained in the examples and comparative examples were used as the negative electrode active material. The conductive agent was acetylene black, the binder was polyvinylidene fluoride, and the negative electrode current collector was a 6μm thick aluminum foil. The negative electrode active material, conductive agent, and binder were mixed at a mass ratio of 8:1:1, and N-methylpyrrolidone was added and stirred to form a uniform and stable negative electrode slurry. The negative electrode slurry was then uniformly coated onto the surface of the negative electrode current collector using a 200μm doctor blade coating. After drying and cold pressing, the negative electrode sheet was obtained with a mass loading of approximately 2.5 mg / cm³. 2 .

[0083] Counter electrode: Sodium metal sheet.

[0084] Separating membrane: Polyethylene film, 9μm thick.

[0085] Electrolyte: Sodium hexafluorophosphate is dissolved in polycarbonate to prepare an electrolyte with a concentration of 1 mol / L.

[0086] Sodium-ion battery assembly: Arrange the negative electrode, separator, counter electrode, and separator in sequence to assemble the CR2032 coin cell sodium-ion battery.

[0087] Test case

[0088] Specific capacity test: The battery was charged / discharged at a rate of 0.1 C within a voltage range of 0 V-3 V. The specific capacity of the active material was calculated using the formula C=QD / M, where QD is the discharge capacity and M is the mass of the active material. The battery was also charged / discharged at a rate of 10 C within a voltage range of 0 V-3 V, and the 10C specific capacity was recorded.

[0089] Cyclic stability testing was conducted by first performing a 0.1C capacity calibration and recording the discharge capacity as C0. Then, a 1C charge-discharge cycle was performed (charged to 3V, discharged to 0V). A 0.1C capacity calibration was performed every 100 cycles, and the capacity retention rate was recorded after the 5th cycle. The capacity retention rate R = C5 / C0*100% was calculated using the discharge capacity C5 from the 5th 0.1C capacity calibration to evaluate the 500-cycle stability of the negative electrode material.

[0090] The performance of sodium-ion batteries assembled with the active materials obtained in the examples and comparative examples is shown in Table 1.

[0091] Table 1

[0092] Group allocation ratio First-round reversible capacity mAh / g 500-cycle retention rate 10C rate capacity Example 1 <![CDATA[Ti3N5:Sn:C=60:38:2]]> 425 88.4% 375.5 Example 2 <![CDATA[Ti3N5:Sn:C=50:48:2]]> 453 57.5% 317.0 Example 3 <![CDATA[Ti3N5:Sb:C=60:38:2]]> 403 88.3% 364.3 Comparative Example 1 Sn:C=98:2 700 5.1% 135.6 Comparative Example 2 <![CDATA[Ti3N5:Sn:C=60:38:2]]> 438 25.8% 214.0 Comparative Example 3 <![CDATA[Ti3N5:Sn:C=40:58:2]]> 545 35.7% 206.4

[0093] As shown in Table 1, the batteries with negative electrode materials obtained in Examples 1 and 3 exhibit excellent electrical performance. In Example 1, the three-dimensional Ti3N5 structure suppresses volume expansion and optimizes conductivity. By optimizing the ratio of Ti3N5 to Sn and carbon coating, a balance between high capacity (425 mAh / g) and long cycling performance (88.4% retention) is achieved. In Example 2, the increased Sn content leads to a certain degree of decrease in cycling stability. This is mainly because the volume expansion stress generated by excessive Sn nanoparticles during charging and discharging exceeds the effective constraint limit of the Ti3N5 framework, causing micro-damage to begin to appear in the structure and gradually accumulate. Furthermore, in Comparative Example 3, the further increase in Sn content leads to structural failure, with a cycling retention rate as low as 35.7%. This indicates that when the active material content is too high, the confinement effect of the rigid Ti3N5 framework is weakened, and it cannot effectively resist repeated volume changes, ultimately causing electrode material pulverization, contact failure, and continuous rupture and reconstruction of the solid electrolyte interface (SEI film), resulting in rapid capacity decay.

[0094] In Comparative Example 1, without the Ti3N5 three-dimensional structure to suppress volume expansion, the 10C rate capacity was 135.6 mAh / g. Although the theoretical capacity was high (700 mAh / g), the actual rate performance was significantly reduced, which confirms the limitations of Sn anodes. That is, without rigid framework support, the huge volume effect severely restricts its high rate performance and cycle life.

[0095] In Comparative Example 2, a porous Ti3N5 material was first prepared and then filled with Sn nanoparticles. Its performance (cycle retention rate of only 25.8%) was far inferior to that of Example 1, which used in-situ composite. This demonstrates the superiority of the "one-step" in-situ synthesis strategy: this method ensures that Sn nanoparticles are confined within the Ti3N5 framework during its formation, forming a tight chemical bond and interconnected conductive path. However, the subsequent physical mixing in Comparative Example 2 cannot achieve this atomic-level close contact, resulting in increased electron / ion transport impedance and poor confinement effect. Therefore, the synergistic effect and structural stability are significantly reduced.

[0096] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A composite anode material based on a titanium nitride framework, characterized in that, It includes a matrix framework, a capacity-providing unit embedded in the matrix framework, and a coating layer; the matrix framework is made of titanium nitride, and the capacity-providing unit is one or both of nanoscale Sn and Sb.

2. The composite anode material based on a titanium nitride framework as described in claim 1, characterized in that, The mass percentage of the matrix skeleton is 40-70%, the mass percentage of the capacity providing unit is 20-50%, and the mass percentage of the covering layer is 1-10%.

3. The composite anode material based on a titanium nitride framework as described in claim 1, characterized in that, The matrix framework is a three-dimensional porous structure with a pore size of 5-50 nm.

4. The composite anode material based on a titanium nitride framework as described in claim 1, characterized in that, The coating layer is a carbon layer with a thickness of 2-5 nm.

5. A method for preparing a composite anode material based on a titanium nitride framework as described in any one of claims 1-4, characterized in that, Includes the following steps: S1. Mix and dissolve TiO2, urea, and M salt to obtain a homogeneous solution; wherein M is Sn and / or Sb, and M salt is a chloride. S2. Ammonia water is added dropwise to carry out ammoniation reaction, and the precursor precipitate is obtained after aging. S3. The precursor precipitate is calcined in stages at 300-500℃, 500-600℃, 600-700℃, and 700-800℃, and then cooled to obtain Ti3N5@M; S4. After coating a carbon layer on the surface of Ti3N5@M by glucose-assisted hydrothermal method, the composite anode material based on titanium nitride framework is obtained by ball milling and dispersion.

6. The method for preparing the composite anode material based on a titanium nitride framework as described in claim 5, characterized in that, In S2, the pH of the ammoniation reaction is 8.5-9.5, and the temperature is 60-80℃.

7. The method for preparing the composite anode material based on a titanium nitride framework as described in claim 5, characterized in that, In S3, the segmented calcination specifically includes: (1) Under an air or oxygen atmosphere, heat the material to 300-500℃ at a rate of 2±0.2℃ / min and keep it at that temperature to remove surface organic matter and adsorbed water; (2) Under a mixed atmosphere of hydrogen and nitrogen, the temperature is increased to 500-600℃ at a rate of 1.5±0.2℃ / min and held at that temperature to reduce M salt to M and TiO2 to suboxide, thereby activating the lattice to promote the subsequent nitriding reaction. (3) Under an ammonia atmosphere, the temperature is raised to 600-700℃ at a rate of 1±0.2℃ / min and held to convert the titanium suboxide into Ti3N5, while inhibiting the oxidation of M particles to maintain stability. (4) Under a mixed atmosphere of nitrogen and argon, the temperature was increased to 800-900℃ at a rate of 0.5±0.2℃ / min and held for heat treatment to optimize the Ti3N5 lattice.

8. The method for preparing the composite anode material based on a titanium nitride framework as described in claim 5, characterized in that, In S3, the cooling rate is ≤5℃ / min.

9. The method for preparing the composite anode material based on a titanium nitride framework as described in claim 5, characterized in that, In S4, the temperature of the hydrothermal method is 160-180℃; And / or, the ball milling dispersion speed is 300-500 rpm, and the particle size D50 after ball milling is 80-150 nm.

10. The application of the composite anode material based on a titanium nitride framework as described in any one of claims 1-4 in a battery.