Three-dimensional porous negative electrode material, preparation method and application thereof

Abstract

This invention belongs to the field of electrochemistry, specifically relating to a three-dimensional porous anode material, its preparation method, and its applications. The three-dimensional porous anode material comprises a Cu-doped porous carbon framework, with TiO2 and Co loaded both within the pores and on the surface of the Cu-doped porous carbon framework. This invention achieves integrated construction of a conductive framework and a porous structure. Cu doping improves the interfacial bonding strength, suppresses component separation, and enhances the mechanical stability of the carbon framework; the Co loading improves the material's conductivity, ensuring a rapid electron transport pathway; and the introduction of TiO2 enhances the conductivity of the TiO2. 4+ This method can modulate the electronic structure of MOF derivatives, lower the lithium-ion migration barrier, alleviate volume expansion, and suppress lithium dendrite formation. In summary, this material combines high specific surface area with structural stability, providing abundant active sites and lithium-ion storage space to ensure efficient mass transport, while also achieving excellent electrical conductivity.

Description

Technical Field

[0001] This invention belongs to the field of electrochemistry, specifically relating to a three-dimensional porous anode material, its preparation method, and its application. Background Technology

[0002] 3D porous conductive carbon materials have an urgent need for applications in electrochemical energy storage, electrocatalysis, and sensors due to their high specific surface area, good conductive network and stable three-dimensional structure.

[0003] Currently, there are many methods for 3D fabrication, such as template methods and sol-gel methods. However, these traditional methods suffer from complex steps, difficulty in controlling pore structure, and uneven conductivity, limiting their large-scale application in electrochemical devices. Physical vapor deposition (PVD), especially magnetron sputtering, is a mature thin film deposition process capable of producing uniform and dense carbon films on substrates, providing a good foundation for material conductivity. However, magnetron sputtering alone can only form two-dimensional dense films, making it difficult to construct three-dimensional porous structures. This results in a significantly insufficient specific surface area, failing to meet the requirements of catalysis, energy storage, and other applications.

[0004] In addition, metal-organic framework (MOF) materials are considered ideal precursors for carbon materials due to their highly ordered pore structure and ultra-large specific surface area. However, when MOF precursors are directly pyrolyzed, the three-dimensional framework structure is prone to collapse due to the rapid decomposition of organic ligands and the aggregation of metal components. The resulting carbon materials often have poor conductivity, which seriously limits their direct application as electrode materials.

[0005] Therefore, constructing a structurally stable, porous, and highly conductive three-dimensional porous carbon material to achieve integrated "conductive framework-porous structure" is an urgent technical challenge to be solved. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a three-dimensional porous anode material, its preparation method, and its applications. The three-dimensional porous anode material designed in this invention achieves integrated "conductive framework-porous structure" and synergistic enhancement between the porous carbon framework and functional components. Specifically, Cu doping in the porous carbon framework not only significantly improves the interfacial bonding strength and effectively suppresses component separation, but also enhances the mechanical stability of the carbon framework, fundamentally avoiding structural collapse during material use; the Co loading further improves the intrinsic conductivity of the material, ensuring a rapid electron transport pathway; simultaneously, the introduction of TiO2 enhances the conductivity of TiO2. 4+This material can modulate the electronic structure of MOF derivatives, lower the lithium-ion migration barrier, alleviate volume expansion, and effectively suppress lithium dendrite formation. In summary, this material combines high specific surface area with structural stability, providing abundant active sites and lithium-ion storage space to ensure efficient mass transport, while also achieving excellent conductivity. It can be widely used in energy storage, catalysis, and sensing.

[0007] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a three-dimensional porous anode material, the three-dimensional porous anode material comprising a Cu-doped porous carbon framework, wherein TiO2 and Co are loaded in the pores and on the surface of the Cu-doped porous carbon framework.

[0008] The three-dimensional porous anode material designed in this invention achieves integrated "conductive framework-porous structure" and synergistic enhancement of the porous carbon framework and functional components. Specifically, Cu doping in the porous carbon framework not only significantly improves the interfacial bonding strength and effectively suppresses component separation, but also enhances the mechanical stability of the carbon framework, fundamentally avoiding the problem of structural collapse during material use; the Co loading further improves the intrinsic conductivity of the material, ensuring a fast electron transport pathway; simultaneously, the introduction of TiO2 enables Ti... 4+ This material can modulate the electronic structure of MOF derivatives, lower the lithium-ion migration barrier, alleviate volume expansion, and effectively suppress lithium dendrite formation. In summary, this material combines high specific surface area with structural stability, providing abundant active sites and lithium-ion storage space to ensure efficient mass transport, while also achieving excellent conductivity. It can be widely used in energy storage, catalysis, and sensing.

[0009] Preferably, the specific surface area of ​​the three-dimensional porous anode material is 1500-2500 m². 2 / g, for example, could be 1500m 2 / g、2000m 2 / g or 2500m 2 / g etc.

[0010] It should be noted that the specific surface area of ​​three-dimensional porous anode materials can be measured using the BET test method.

[0011] The three-dimensional porous anode material designed in this invention has a high specific surface area, which can provide more active sites and ensure efficient mass transport.

[0012] Preferably, the Cu doping amount in the Cu-doped porous carbon framework is 1-13 wt%, for example, it can be 1 wt%, 5 wt%, 7 wt%, 9 wt%, 10 wt%, 11 wt%, 12.5 wt%, or 13 wt%.

[0013] In this invention, an appropriate amount of Cu doping forms a uniformly distributed Cu-carbon composite in the porous carbon framework, which can enhance the mechanical strength of the porous carbon framework, effectively suppress structural collapse, and improve the stability of interfacial bonding.

[0014] Preferably, the loading of TiO2 in the Cu-doped porous carbon framework is 0.5-10 wt%, for example, it can be 0.5 wt%, 1 wt%, 2 wt%, 2.5 wt%, 3 wt%, 5 wt%, 7.5 wt%, or 10 wt%.

[0015] In this invention, an appropriate loading of TiO2 can effectively reduce the lithium-ion migration barrier, alleviate volume expansion, and suppress lithium dendrite formation.

[0016] Preferably, the particle size D50 of the TiO2 is ≤50nm, for example, it can be 10nm, 20nm, 30nm, 40nm or 50nm.

[0017] In this invention, with a suitable particle size, TiO2 can be uniformly dispersed in the carbon skeleton, increasing the contact area of ​​the active interface and improving the efficiency of electrochemical reaction.

[0018] Preferably, the loading of Co in the Cu-doped porous carbon framework is 0.5-10 wt%, for example, it can be 0.5 wt%, 1 wt%, 2 wt%, 2.5 wt%, 3 wt%, 5 wt%, 7.5 wt%, or 10 wt%.

[0019] In this invention, an appropriate loading of Co can significantly improve the intrinsic conductivity of the material and enhance the electron transport speed.

[0020] Preferably, the Cu-doped porous carbon framework has a hierarchical porous structure consisting of micropores, mesopores, and macropores. It should be noted that micropores refer to pores with a diameter less than 2 nm, mesopores refer to pores with a diameter of 2-50 nm, and macropores refer to pores with a diameter greater than 50 nm.

[0021] This invention provides a rich pore structure (micropores, mesopores, and macropores coexisting), which can ensure rapid material transport, alleviate volume expansion, and suppress the formation of lithium dendrites.

[0022] Preferably, the conductivity of the Cu-doped porous carbon framework is ≥1×10⁻⁶. 4 S / m, for example, could be 1×10 4 S / m, 2×10 4 S / m, 3×10 4 S / m, 4×10 4 S / m, 5×10 4 S / m or 6×10 4 S / m, etc.

[0023] It should be noted that conductivity can be obtained by any of the following methods: four-probe method, AC impedance method, or DC voltammetry method.

[0024] Preferably, the porosity of the three-dimensional porous negative electrode material is >25%, for example, it can be 30%, 40%, 50%, 60%, 70%, 80% or 90%, etc.

[0025] It should be noted that porosity can be obtained by any of the following methods: liquid nitrogen adsorption-desorption, mercury porosimetry, or gas displacement.

[0026] Preferably, the thickness of the three-dimensional porous anode material is 0.5-10 μm, for example, it can be 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm, etc.

[0027] Preferably, the surface of the Cu-doped porous carbon framework contains active functional groups, which include any one or a combination of at least two of the following: hydroxyl (-OH), carboxyl (-COOH), amino (-NH2), carbonyl (C=O), or epoxy (-O-).

[0028] This invention introduces active functional groups on the surface of a Cu-doped porous carbon framework, which is beneficial for enhancing the interaction between the framework and the electrolyte, improving wettability, and simultaneously constructing more electrochemical active centers in conjunction with Cu doping sites, promoting the adsorption and transport of lithium / sodium ions, suppressing side reactions in the electrode reaction process, and thus improving the energy storage capacity, rate performance and cycle stability of the anode material.

[0029] In a second aspect, the present invention provides a method for preparing a three-dimensional porous anode material as described in the first aspect, the method comprising the following steps: A carbon film is deposited on a substrate using physical vapor deposition to obtain a carbon-coated substrate.

[0030] The carbon-plated substrate is placed in an MOF precursor solution and impregnated to form an intermediate; wherein the MOF precursor solution includes a Cu source, a Co source, TiO2 particles and an organic ligand.

[0031] The intermediate is subjected to heat treatment and cooling to form the three-dimensional porous anode material.

[0032] The preparation method provided by this invention is simple, highly controllable, and effectively combines the advantages of physical vapor deposition (PVD) and MOF materials, achieving the integrated construction of a "conductive framework-porous structure." Specifically, firstly, a carbon film is formed on the substrate surface using PVD as the initial conductive framework; then, the carbon-plated substrate is immersed in an MOF precursor solution, utilizing interfacial adsorption and diffusion to allow MOF particles to fully fill the carbon film surface and potential micropores; finally, the immersed intermediate is heat-treated and cooled, causing the MOF organic ligands to decompose and generate gases such as CO2 and H2, forming new pores within the carbon film framework. Simultaneously, the MOF is reduced to metal nanoparticles or combines with carbon to form metal-carbon complexes, further enhancing the material's conductivity and structural stability.

[0033] In the impregnation process of this invention, the -COOH on the surface of the carbon film reacts with the Cu in the MOF precursor solution. 2+ Coordination bonds (Cu-OC) are formed, serving as nucleation sites, and the organic ligands gradually bind with Cu. 2+ The organic ligands are combined and grown along the substrate surface to form a thin film. During the heat treatment process, the organic ligands undergo thermal decomposition, producing gases such as CO2, H2, and CH4. These gases are released from the carbon film framework, forming new pores. At the same time, Cu atoms diffuse into the carbon matrix during the pyrolysis process, forming a Cu-doped porous carbon framework. The interfacial bonding strength is significantly improved, and component separation is significantly suppressed.

[0034] Preferably, the Cu source comprises copper nitrate. For example, it could be copper nitrate trihydrate, etc.

[0035] Preferably, the Co source comprises cobalt nitrate. For example, it could be cobalt nitrate hexahydrate, etc.

[0036] Preferably, the organic ligand comprises any one or a combination of at least two of pyromellitic acid, terephthalic acid, phthalic acid, or benzoic acid.

[0037] Preferably, the physical vapor deposition method includes magnetron sputtering.

[0038] Preferably, the porosity of the carbon film is 8-60%, for example, it can be 8%, 10%, 20%, 30%, 40%, 50% or 60%, etc.

[0039] The carbon film prepared by this invention has a certain porosity, which can provide a channel for the penetration of MOF precursor solution in the subsequent impregnation process, ensuring that the MOF precursor not only covers the surface of the carbon film, but also fills the pores of the carbon film to form a tightly composite intermediate, which is beneficial to improve the uniformity of loading, thereby improving the specific surface area and structural stability of the final material.

[0040] Preferably, the thickness of the carbon film is 30-100nm, for example, it can be 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm or 100nm, etc.

[0041] Preferably, the temperature of the impregnation treatment is 25-40℃, such as 25℃, 28℃, 30℃, 32℃, 35℃, 38℃ or 40℃, and the time is 24-36h, such as 24h, 26h, 28h, 30h, 32h, 34h or 36h.

[0042] Preferably, in the MOF precursor solution, the mass ratio of copper source to cobalt source is (8-10):1, for example, it can be 8:1, 8.5:1, 9:1, 9.5:1 or 10:1, etc.

[0043] Preferably, in the MOF precursor solution, the mass ratio of copper source to TiO2 particles is (8-12):1, for example, it can be 8:1, 9:1, 10:1, 11:1 or 12:1, etc.

[0044] Preferably, in the MOF precursor solution, the mass ratio of copper source to organic ligand is (1.5-5):1, for example, it can be 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1 or 5:1, etc.

[0045] Preferably, the heat treatment includes a sequential heating stage and a isothermal stage; the heating rate of the heating stage is 5-10℃ / min, for example, 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min, or 10℃ / min; the temperature of the isothermal stage is 750-800℃, for example, 750℃, 760℃, 770℃, 780℃, 790℃, or 800℃; the holding time of the isothermal stage is 1.5-2.5h, for example, 1.5h, 1.8h, 2.0h, 2.2h, or 2.5h.

[0046] This invention employs a gradient heating method, initially using a heating rate of 5-10℃ / min to prevent the rapid decomposition of organic ligands due to sudden temperature increases, which could generate a large amount of gas impacting the carbon skeleton and ensure structural integrity. An excessively rapid heating rate can lead to the rapid decomposition of MOF organic ligands, generating a large amount of gas impacting the carbon skeleton and causing structural collapse; an excessively slow rate would prolong the preparation cycle and increase energy consumption. Finally, an isothermal stage is performed to fully carbonize the MOF precursor, forming a stable three-dimensional porous structure.

[0047] The present invention limits the temperature of the isothermal stage to 750-800℃. At this temperature, the MOF precursor can be fully carbonized, while avoiding excessive graphitization and pore collapse caused by excessive temperature, thus achieving synergistic optimization of specific surface area and conductivity.

[0048] Preferably, the atmosphere for the heat treatment is an inert atmosphere containing hydrogen. For example, it may be a nitrogen atmosphere or an argon atmosphere.

[0049] The purpose of introducing hydrogen into the heat treatment atmosphere in this invention is to reduce and remove oxide impurities and residual oxygen-containing functional groups on and inside the material surface, while simultaneously etching to control the pore structure and form active sites.

[0050] Preferably, in the hydrogen-containing inert atmosphere, the volume fraction of hydrogen is 4-6%, for example, it can be 4%, 5% or 6%, etc.

[0051] Preferably, the temperature during the isothermal stage and the specific surface area of ​​the three-dimensional porous anode material satisfy the following relationship: S=a×T 2 +b×T+C, where S is the specific surface area of ​​the three-dimensional porous anode material, T is the temperature during the isothermal stage, and a, b and C are the fitting coefficient, temperature influence coefficient and constant term, respectively, and 750℃≤T≤800℃.

[0052] It should be noted that, within the temperature range of 750-800℃, the specific surface area S of the three-dimensional porous anode material exhibits a quadratic function relationship with the pyrolysis temperature T, and the coefficient a of the quadratic term is negative.

[0053] This invention achieves the above relationship between the temperature during the isothermal stage and the specific surface area of ​​the three-dimensional porous anode material, thereby obtaining a three-dimensional porous carbon framework with the maximum specific surface area. At the same time, it achieves uniform loading of TiO2 and Co in the Cu-doped carbon framework, which significantly improves the ion transport efficiency and structural stability of the material, resulting in anode materials with high specific capacity, excellent rate performance and long cycle life.

[0054] Preferably, after cooling, an activation treatment is performed, the activation treatment step including: The cooled negative electrode material is placed in an activation solution to carry out an activation reaction.

[0055] The activation solution includes a KOH aqueous solution with a mass fraction of 2-12%, such as 2%, 4%, 6%, 8%, 10%, or 12%. The activation reaction temperature is 100-200℃, such as 100℃, 120℃, 140℃, 160℃, 180℃, or 200℃, and the holding time is 0.5-1.5h, such as 0.5h, 0.8h, 1.0h, 1.2h, or 1.5h.

[0056] This invention uses an activation solution to activate the negative electrode material. At the above temperature, KOH will selectively etch the material surface, forming new pores on the basis of the original channels. This is beneficial to further increase the specific surface area of ​​the negative electrode material. At the same time, it introduces active functional groups, which is beneficial to increase electrochemical active sites, improve electrolyte wettability, promote rapid ion transport, and thus improve the lithium / sodium storage capacity and rate performance of the material.

[0057] Preferably, the activation treatment step includes: The cooled negative electrode material is placed in an activation solution and allowed to stand at room temperature for 0.5-1 hour (e.g., 0.5 hours, 0.75 hours, or 1 hour). Then, it is dehydrated and dried at 80-100°C (e.g., 80°C, 90°C, or 100°C) for 1-2 hours (e.g., 1 hour, 1.5 hours, or 2 hours). After drying, it is placed in a tube furnace under an air or inert atmosphere (e.g., nitrogen or argon) and heated to 100-200°C (e.g., 100°C, 150°C, or 200°C) at a rate of 4-6°C / min (e.g., 4°C / min, 5°C / min, or 6°C / min) for 0.5-1.5 hours (e.g., 0.5 hours, 1 hour, or 1.5 hours). After drying, it is allowed to cool naturally to room temperature. Finally, it is washed with water until the pH of the washing solution is close to 7, dried, and the activation is complete.

[0058] Preferably, the preparation method includes the following steps: (1) Substrate pretreatment: The substrate is cleaned and dried to obtain a pretreated substrate; the substrate includes copper foil.

[0059] (2) Carbon film deposition by magnetron sputtering: The pretreated substrate is placed in a magnetron sputtering apparatus and a vacuum is drawn; the target material in the magnetron sputtering apparatus includes graphite.

[0060] A working gas is introduced into the vacuum chamber for pre-sputtering treatment. The pre-sputtering power is 70-90W (e.g., 70W, 75W, 80W, 85W, or 90W), and the pre-sputtering time is 4-6 minutes (e.g., 4 minutes, 4.5 minutes, 5 minutes, 5.5 minutes, or 6 minutes). After pre-sputtering, the sputtering deposition process is performed, with the sputtering power increased to 100-300W (e.g., 100W, 150W, 200W, 250W, or 300W), and the sputtering time is 25-35 minutes (e.g., [missing information]). The deposition process takes 25 min, 28 min, 30 min, 32 min, or 35 min, etc., to form a carbon film with a thickness of 30-100 nm. After deposition, the film is naturally cooled to room temperature to obtain a carbon-coated substrate. The working gas includes argon gas, and the flow rate of the working gas is 15-25 sccm (e.g., 15 sccm, 18 sccm, 20 sccm, 22 sccm, or 25 sccm, etc.). The target-substrate distance is 7-9 cm (e.g., 7 cm, 7.5 cm, 8 cm, 8.5 cm, or 9 cm, etc.).

[0061] (3) A metal salt solution is prepared by mixing Cu source, Co source, TiO2 particles and solvent (e.g., N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), ethanol, acetonitrile (CH3CN) or ethylene glycol (HOCH2CH2OH)). An organic ligand solution is prepared by mixing organic ligand and solvent (e.g., N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), ethanol, acetonitrile (CH3CN) or ethylene glycol (HOCH2CH2OH)). The metal salt solution and the ligand solution are mixed to obtain an MOF precursor solution. The organic ligand includes trimesic acid and / or 2-methylimidazole.

[0062] The carbon-plated substrate is immersed in the MOF precursor solution and left to stand at 25-40°C for 24-36 hours for impregnation treatment. After the impregnation is completed, it is dried to obtain the intermediate.

[0063] (4) Pyrolysis forms a three-dimensional porous anode material: The intermediate was placed in an inert atmosphere containing hydrogen, and the heating rate was set to 5-10℃ / min. The temperature was increased from room temperature to 750-800℃ for heat treatment, and then the temperature was kept constant for 1.5-2.5h for isothermal heat treatment.

[0064] After the process was completed, the material was allowed to cool naturally to room temperature, resulting in a three-dimensional porous anode material.

[0065] The purpose of pre-sputtering in this invention is to remove the oxide layer and impurities on the surface of the graphite target, so as to ensure the purity of the carbon film deposited subsequently.

[0066] It should be noted that if the target-substrate distance is too close, the substrate temperature may become too high, and the carbon film may crack. If the distance is too far, the number of sputtered particles reaching the substrate will decrease, resulting in uneven carbon film thickness.

[0067] Thirdly, the present invention provides an application of the three-dimensional porous anode material as described in the first aspect in the field of electrochemistry.

[0068] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0069] Compared with the prior art, the present invention has the following beneficial effects: The three-dimensional porous anode material designed in this invention achieves integrated "conductive framework-porous structure" and synergistic enhancement of the porous carbon framework and functional components. Specifically, Cu doping in the porous carbon framework not only significantly improves the interfacial bonding strength and effectively suppresses component separation, but also enhances the mechanical stability of the carbon framework, fundamentally avoiding the problem of structural collapse during material use; the Co loading further improves the intrinsic conductivity of the material, ensuring a fast electron transport pathway; simultaneously, the introduction of TiO2 enables Ti... 4+ This material can modulate the electronic structure of MOF derivatives, lower the lithium-ion migration barrier, alleviate volume expansion, and effectively suppress lithium dendrite formation. In summary, this material combines high specific surface area with structural stability, providing abundant active sites and lithium-ion storage space to ensure efficient mass transport, while also achieving excellent conductivity. It can be widely used in energy storage, catalysis, and sensing. Attached Figure Description

[0070] Figure 1 This is a process flow diagram provided in Embodiment 1 of the present invention. Detailed Implementation

[0071] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0072] The scope of this invention can be defined by lower and upper limits. The selected lower and upper limits define the boundaries of a specific range. The range defined in this way can be defined by the inclusion or exclusion of endpoints. Any endpoint can be independently selected for inclusion or exclusion, and all lower and upper limits can be arbitrarily combined to form new ranges. That is, any lower limit can be combined with any upper limit to form an effective range. For example, if the ranges of 60~120 and 80~110 are listed for specific parameters, it should be understood that the ranges of 60~110 and 80~120 also fall within the scope of this invention. In addition, if the minimum range values ​​1 and 2 are listed, and the maximum range values ​​3, 4 and 5 are also listed, then all ranges of 1~3, 1~4, 1~5, 2~3, 2~4 and 2~5 fall within the scope of this invention. In this invention, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0~5" means that all real numbers between 0 and 5 have been fully listed in this document, and "0~5" is only a shortened representation of this set of numerical combinations. When a parameter is expressed as an integer ≥2, it is equivalent to listing positive integers that meet the requirements, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, etc. When a parameter is expressed as an integer selected from "2~10", it is equivalent to listing any integer among 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0073] In this invention, "a combination of at least two" refers to a quantity greater than or equal to 2 unless otherwise specified. For example, "any one or a combination of at least two" means that any one of the listed items can be selected, or a combination of at least two of the listed items formed in a manner that does not conflict and enables the implementation of this invention. In this invention, unless otherwise specified, the features or solutions corresponding to "and / or" cover any one of two or more related listed items, as well as any and all combinations of the related listed items. The arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" means a set consisting of A, B, and combinations of A and B, where "containing A and / or B" can be understood, depending on the context of the statement, as containing A, containing B, or simultaneously containing both A and B. In this invention, "optional" means that the corresponding feature, component, step or solution is not necessary, that is, it is selected from either "with" or "without". If there are multiple "optional" limitations in a technical solution, unless otherwise specified and there is no technical conflict or mutual constraint, each "optional" limitation is independent and does not affect the others.

[0074] In this invention, technical features or solutions described using open-ended terms such as "comprising" or "including" do not exclude additional non-conflicting elements beyond the listed elements unless otherwise specified. They are considered to disclose both closed-ended features or solutions consisting solely of the listed elements and open-ended features or solutions that may include additional non-conflicting elements beyond the listed elements. For example, if A includes a1, a2, and a3, unless otherwise specified, this means that A can consist only of a1, a2, and a3, or it can include other non-conflicting elements based on a1, a2, and a3. This corresponds to the disclosure of technical solutions such as "A consists of a1, a2, and a3," "A is selected from a1, a2, and a3," and "A not only includes a1, a2, and a3, but may also include other non-conflicting elements." All embodiments and optional embodiments of this invention, unless otherwise specified and without technical conflict, can be combined to form new technical solutions, and such combinations fall within the scope of this invention. The term "embodiment" as used in this invention means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of the invention. The appearance of this phrase in various locations throughout the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will understand, explicitly and implicitly, that the embodiments described in this invention can be combined with other embodiments that do not conflict with the technology. The ordinal numbers "first," "second," "third," and "fourth," etc., used in the expressions "first aspect," "second aspect," "third aspect," and "fourth aspect" in this invention are for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly specifying the importance or quantity of the indicated technical features. They serve only as a non-exhaustive enumeration and do not constitute a closed limitation on quantity.

[0075] In this invention, the order in which the steps are written in the methods described in each embodiment does not imply a strict execution order. The actual execution order of each step should be determined based on its function and possible internal logic. Unless otherwise specified, all steps of this invention can be executed in the order they are written, or in any order without technical conflict. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) executed sequentially, or it may include steps (b) and (a) executed sequentially. If the method also includes step (c), then step (c) can be added to the method in any order without conflict, including but not limited to the execution order of steps (a), (b), and (c), steps (a), (c), and (b), steps (c), (a), and (b), etc.

[0076] It should be noted that the room temperature below refers to 25℃.

[0077] Example 1 This embodiment provides a three-dimensional porous anode material, which includes a Cu-doped porous carbon framework, wherein TiO2 and Co are loaded in the pores and on the surface of the Cu-doped porous carbon framework.

[0078] In the Cu-doped porous carbon framework, the Cu doping amount is 1.5%, the TiO2 loading amount is 3.5wt%, and the Co loading amount is 1.5wt%; the TiO2 particle size D50 is 20nm; the Cu-doped porous carbon framework has a multi-level porous structure composed of micropores, mesopores, and macropores; the thickness of the three-dimensional porous anode material is 1μm.

[0079] This embodiment also provides a method for preparing the above-mentioned three-dimensional porous anode material, the process flow diagram of which is shown below. Figure 1 As shown, the preparation method includes the following steps: (1) Substrate pretreatment: The copper foil was placed in an ultrasonic cleaning tank containing acetone, with the ultrasonic power set to 300W and the ultrasonic time set to 15 minutes to remove oily contaminants from the substrate surface. It was then transferred to an ultrasonic cleaning tank containing ethanol, with the ultrasonic power set to 300W and the ultrasonic time set to 15 minutes to remove residual acetone and water-soluble impurities. It was then rinsed three times with deionized water, each rinse lasting 1 minute, to ensure no ethanol residue remained. Finally, the cleaned copper foil was placed in a vacuum oven, with the temperature set to 80℃ and the vacuum level set to 1×10⁻⁶. -2 Pa, drying time is 2 hours, and after drying, immediately transfer to a desiccator for later use.

[0080] (2) Carbon film deposition by magnetron sputtering: The pretreated substrate was placed in a magnetron sputtering apparatus (medium frequency magnetron sputtering instrument, model: JGP-450), and the target material included high-purity graphite (purity 99.99%, size Φ60mm×5mm).

[0081] Turn on the vacuum system of the magnetron sputtering equipment. First, use a mechanical pump to evacuate the vacuum chamber to below 5 Pa, then start the molecular pump and continue evacuating to 5.0 × 10⁻⁶ Pa. -4 Pa.

[0082] Argon gas (99.999% purity) with a flow rate of 20 sccm was introduced into the vacuum chamber as the working gas for pre-sputtering treatment. The pre-sputtering power was 80W and the pre-sputtering time was 5 min. After the pre-sputtering was completed, the sputtering deposition process was carried out, with the sputtering power increased to 150W and the sputtering time being 30 min. The argon gas flow rate and target-substrate distance were kept constant to form a carbon film with a thickness of 40 nm and a porosity of 20%. After the deposition was completed, the sputtering power supply and argon gas valve were turned off. The vacuum chamber was allowed to cool naturally to room temperature. The vacuum was then slowly released to atmospheric pressure, the vacuum chamber was opened, and the carbon-coated substrate was removed. The target-substrate distance was 8 cm.

[0083] (3) MOF precursor solution impregnation to form intermediates: 1.2 g of copper nitrate trihydrate (purity ≥99%), 0.12 g of cobalt nitrate hexahydrate, and 0.12 g of TiO2 particles were dissolved in 20 mL of DMF and stirred until completely dissolved to prepare a metal salt solution. 0.4 g of trimesic acid (purity ≥99%) was dissolved in 20 mL of DMF and stirred until completely dissolved to obtain a ligand solution. The metal salt solution was slowly poured into the ligand solution, and stirring was continued for 20 min to obtain a MOF precursor solution. The mass ratio of copper nitrate trihydrate to cobalt nitrate hexahydrate was 10:1, the mass ratio of copper nitrate trihydrate to TiO2 particles was 10:1, and the mass ratio of copper nitrate trihydrate to trimesic acid was 3:1.

[0084] A 50mL glass culture dish was used. The inner wall was wiped with ethanol and then dried to ensure no impurities remained. The carbon-coated substrate was placed flat and immersed in the MOF precursor solution, with the carbon film facing upwards. It was left to stand at 30℃ for 30 hours for immersion treatment. After immersion, the substrate edges were carefully picked up with tweezers, and the solution was slowly removed. The substrate was then placed in a vacuum oven for drying at 60℃ and a vacuum degree of 1×10⁻⁶. -2 Pa, drying time 12h, to obtain intermediate.

[0085] (4) Pyrolysis forms a three-dimensional porous anode material: A tube furnace (model: OTF-1200X) is selected, and a corundum boat is placed inside the furnace chamber. The intermediate body is placed flat in the center of the corundum boat.

[0086] Introduce nitrogen gas at a flow rate of 50 sccm for 30 minutes to purge the air from the furnace. Then adjust the atmosphere in the furnace to a nitrogen atmosphere containing hydrogen (hydrogen volume fraction of 5%), while keeping the flow rate constant.

[0087] The heating rate was set to 5℃ / min, and the temperature was increased from room temperature to 800℃ for heat treatment, followed by isothermal heat treatment at a constant temperature for 2 hours. The temperature during the isothermal stage and the specific surface area of ​​the three-dimensional porous negative electrode material satisfy the following relationship: S = a × 800 2 +b×800+C, where S is the specific surface area of ​​the three-dimensional porous anode material, T is the temperature during the isothermal stage, and a, b and C are the fitting coefficient, temperature influence coefficient and constant term, respectively.

[0088] After completion, the heating power of the tubular furnace is turned off, the gas flow rate is kept constant, and the furnace is allowed to cool naturally to room temperature to obtain a three-dimensional porous anode material.

[0089] Example 2 This embodiment provides a three-dimensional porous anode material, which includes a Cu-doped porous carbon framework, wherein TiO2 and Co are loaded in the pores and on the surface of the Cu-doped porous carbon framework.

[0090] In the Cu-doped porous carbon framework, the Cu doping amount is 2%, the TiO2 loading amount is 3.8%, and the Co loading amount is 3.1%; the TiO2 particle size D50 is 20nm; the Cu-doped porous carbon framework has a hierarchical porous structure composed of micropores, mesopores, and macropores; the thickness of the three-dimensional porous anode material is 1μm.

[0091] This embodiment also provides a method for preparing the above-mentioned three-dimensional porous anode material, the method comprising the following steps: (1) Substrate pretreatment: The copper foil was placed in an ultrasonic cleaning tank containing acetone, with the ultrasonic power set to 300W and the ultrasonic time set to 15 minutes to remove oily contaminants from the substrate surface. It was then transferred to an ultrasonic cleaning tank containing ethanol, with the ultrasonic power set to 300W and the ultrasonic time set to 15 minutes to remove residual acetone and water-soluble impurities. It was then rinsed three times with deionized water, each rinse lasting 1 minute, to ensure no ethanol residue remained. Finally, the cleaned copper foil was placed in a vacuum oven, with the temperature set to 80℃ and the vacuum level set to 1×10⁻⁶. -2 Pa, drying time is 2 hours, and after drying, immediately transfer to a desiccator for later use.

[0092] (2) Carbon film deposition by magnetron sputtering: The pretreated substrate was placed in a magnetron sputtering apparatus (medium frequency magnetron sputtering instrument, model: JGP-450), and the target material included high-purity graphite (purity 99.99%, size Φ60mm×5mm).

[0093] Turn on the vacuum system of the magnetron sputtering equipment. First, use a mechanical pump to evacuate the vacuum chamber to below 5 Pa, then start the molecular pump and continue evacuating to 5.0 × 10⁻⁶ Pa. -4 Pa.

[0094] Argon gas (99.999% purity) with a flow rate of 20 sccm was introduced into the vacuum chamber as the working gas for pre-sputtering treatment. The pre-sputtering power was 80W and the pre-sputtering time was 5 min. After the pre-sputtering was completed, the sputtering deposition process was carried out, with the sputtering power increased to 150W and the sputtering time being 30 min. The argon gas flow rate and target-substrate distance were kept constant to form a carbon film with a thickness of 40 nm and a porosity of 20%. After the deposition was completed, the sputtering power supply and argon gas valve were turned off. The vacuum chamber was allowed to cool naturally to room temperature. The vacuum was then slowly released to atmospheric pressure, the vacuum chamber was opened, and the carbon-coated substrate was removed. The target-substrate distance was 8 cm.

[0095] (3) MOF precursor solution impregnation to form intermediates: 1.5 g of copper nitrate trihydrate (purity ≥99%), 0.15 g of cobalt nitrate hexahydrate, and 0.15 g of TiO2 particles were dissolved in 20 mL of DMF and stirred until completely dissolved to prepare a metal salt solution. 0.4 g of trimesic acid (purity ≥99%) was dissolved in 20 mL of DMF and stirred until completely dissolved to obtain a ligand solution. The metal salt solution was slowly poured into the ligand solution, and stirring was continued for 20 min to obtain a MOF precursor solution. The mass ratio of copper nitrate trihydrate to cobalt nitrate hexahydrate was 10:1, the mass ratio of copper nitrate trihydrate to TiO2 particles was 10:1, and the mass ratio of copper nitrate trihydrate to trimesic acid was 3.75:1.

[0096] A 50mL glass culture dish was used. The inner wall was wiped with ethanol and then dried to ensure no impurities remained. The carbon-coated substrate was placed flat and immersed in the MOF precursor solution, with the carbon film facing upwards. It was left to stand at 30℃ for 30 hours for immersion treatment. After immersion, the substrate edges were carefully picked up with tweezers, and the solution was slowly removed. The substrate was then placed in a vacuum oven for drying at 60℃ and a vacuum degree of 1×10⁻⁶. -2 Pa, drying time 12h, to obtain intermediate.

[0097] (4) Pyrolysis forms a three-dimensional porous anode material: A tube furnace (model: OTF-1200X) is selected, and a corundum boat is placed inside the furnace chamber. The intermediate body is placed flat in the center of the corundum boat.

[0098] Introduce nitrogen gas at a flow rate of 50 sccm for 30 minutes to purge the air from the furnace. Then adjust the atmosphere in the furnace to a nitrogen atmosphere containing hydrogen (hydrogen volume fraction of 5%), while keeping the flow rate constant.

[0099] The heating rate was set to 5℃ / min, and the temperature was increased from room temperature to 800℃ for heat treatment, followed by isothermal heat treatment at a constant temperature for 2 hours. The temperature during the isothermal stage and the specific surface area of ​​the three-dimensional porous negative electrode material satisfy the following relationship: S = a × 800 2 +b×800+C, where S is the specific surface area of ​​the three-dimensional porous anode material, T is the temperature during the isothermal stage, and a, b and C are the fitting coefficient, temperature influence coefficient and constant term, respectively.

[0100] After completion, the heating power of the tubular furnace is turned off, the gas flow rate is kept constant, and the furnace is allowed to cool naturally to room temperature to obtain a three-dimensional porous anode material.

[0101] Example 3 This embodiment provides a three-dimensional porous anode material, which includes a Cu-doped porous carbon framework, wherein TiO2 and Co are loaded in the pores and on the surface of the Cu-doped porous carbon framework.

[0102] In the Cu-doped porous carbon framework, the Cu doping amount is 2.5%, the TiO2 loading amount is 4.2%, and the Co loading amount is 3.5%; the TiO2 particle size D50 is 20nm; the Cu-doped porous carbon framework has a hierarchical porous structure composed of micropores, mesopores, and macropores; the thickness of the three-dimensional porous anode material is 1μm.

[0103] This embodiment also provides a method for preparing the above-mentioned three-dimensional porous anode material, the method comprising the following steps: (1) Substrate pretreatment: The copper foil was placed in an ultrasonic cleaning tank containing acetone, with the ultrasonic power set to 300W and the ultrasonic time set to 15 minutes to remove oily contaminants from the substrate surface. It was then transferred to an ultrasonic cleaning tank containing ethanol, with the ultrasonic power set to 300W and the ultrasonic time set to 15 minutes to remove residual acetone and water-soluble impurities. It was then rinsed three times with deionized water, each rinse lasting 1 minute, to ensure no ethanol residue remained. Finally, the cleaned copper foil was placed in a vacuum oven, with the temperature set to 80℃ and the vacuum level set to 1×10⁻⁶. -2 Pa, drying time is 2 hours, and after drying, immediately transfer to a desiccator for later use.

[0104] (2) Carbon film deposition by magnetron sputtering: The pretreated substrate was placed in a magnetron sputtering apparatus (medium frequency magnetron sputtering instrument, model: JGP-450), and the target material included high-purity graphite (purity 99.99%, size Φ60mm×5mm).

[0105] Turn on the vacuum system of the magnetron sputtering equipment. First, use a mechanical pump to evacuate the vacuum chamber to below 5 Pa, then start the molecular pump and continue evacuating to 5.0 × 10⁻⁶ Pa. -4 Pa.

[0106] Argon gas (99.999% purity) with a flow rate of 20 sccm was introduced into the vacuum chamber as the working gas for pre-sputtering treatment. The pre-sputtering power was 80W and the pre-sputtering time was 5 min. After the pre-sputtering was completed, the sputtering deposition process was carried out, with the sputtering power increased to 250W and the sputtering time 30 min. The argon gas flow rate and target-substrate distance were kept constant to form a carbon film with a thickness of 90 nm and a porosity of 20%. After the deposition was completed, the sputtering power supply and argon gas valve were turned off. The vacuum chamber was allowed to cool naturally to room temperature. The vacuum was then slowly released to atmospheric pressure. The vacuum chamber was opened and the carbon-coated substrate was removed. The target-substrate distance was 8 cm.

[0107] (3) MOF precursor solution impregnation to form intermediates: 1.5 g of copper nitrate trihydrate (purity ≥99%), 0.15 g of cobalt nitrate hexahydrate, and 0.15 g of TiO2 particles were dissolved in 20 mL of DMF and stirred until completely dissolved to prepare a metal salt solution. 0.4 g of trimesic acid (purity ≥99%) was dissolved in 20 mL of DMF and stirred until completely dissolved to obtain a ligand solution. The metal salt solution was slowly poured into the ligand solution, and stirring was continued for 20 min to obtain a MOF precursor solution. The mass ratio of copper nitrate trihydrate to cobalt nitrate hexahydrate was 10:1, the mass ratio of copper nitrate trihydrate to TiO2 particles was 10:1, and the mass ratio of copper nitrate trihydrate to trimesic acid was 3.75:1.

[0108] A 50mL glass culture dish was used. The inner wall was wiped with ethanol and then dried to ensure no impurities remained. The carbon-coated substrate was placed flat and immersed in the MOF precursor solution, with the carbon film facing upwards. It was left to stand at 30℃ for 30 hours for immersion treatment. After immersion, the substrate edges were carefully picked up with tweezers, and the solution was slowly removed. The substrate was then placed in a vacuum oven for drying at 60℃ and a vacuum degree of 1×10⁻⁶. -2 Pa, drying time 12h, to obtain intermediate.

[0109] (4) Pyrolysis forms a three-dimensional porous anode material: A tube furnace (model: OTF-1200X) is selected, and a corundum boat is placed inside the furnace chamber. The intermediate body is placed flat in the center of the corundum boat.

[0110] Introduce nitrogen gas at a flow rate of 50 sccm for 30 minutes to purge the air from the furnace. Then adjust the atmosphere in the furnace to a nitrogen atmosphere containing hydrogen (hydrogen volume fraction of 5%), while keeping the flow rate constant.

[0111] The heating rate was set to 10℃ / min, and the temperature was increased from room temperature to 800℃ for heat treatment, followed by isothermal heat treatment at a constant temperature for 2 hours. The temperature during the isothermal stage and the specific surface area of ​​the three-dimensional porous negative electrode material satisfy the following relationship: S = a × 800 2 +b×800+C, where S is the specific surface area of ​​the three-dimensional porous anode material, T is the temperature during the isothermal stage, and a, b and C are the fitting coefficient, temperature influence coefficient and constant term, respectively.

[0112] After completion, the heating power of the tubular furnace is turned off, the gas flow rate is kept constant, and the furnace is allowed to cool naturally to room temperature to obtain a three-dimensional porous anode material.

[0113] Example 4 This embodiment provides a three-dimensional porous anode material, which includes a Cu-doped porous carbon framework, wherein TiO2 and Co are loaded in the pores and on the surface of the Cu-doped porous carbon framework.

[0114] In the Cu-doped porous carbon framework, the Cu doping amount is 3%, the TiO2 loading amount is 4.5%, and the Co loading amount is 4%; the TiO2 particle size D50 is 20nm; the Cu-doped porous carbon framework has a hierarchical porous structure composed of micropores, mesopores, and macropores; the thickness of the three-dimensional porous anode material is 1μm.

[0115] This embodiment also provides a method for preparing the above-mentioned three-dimensional porous anode material, the method comprising the following steps: (1) Substrate pretreatment: The copper foil was placed in an ultrasonic cleaning tank containing acetone, with the ultrasonic power set to 300W and the ultrasonic time set to 15 minutes to remove oily contaminants from the substrate surface. It was then transferred to an ultrasonic cleaning tank containing ethanol, with the ultrasonic power set to 300W and the ultrasonic time set to 15 minutes to remove residual acetone and water-soluble impurities. It was then rinsed three times with deionized water, each rinse lasting 1 minute, to ensure no ethanol residue remained. Finally, the cleaned copper foil was placed in a vacuum oven, with the temperature set to 80℃ and the vacuum level set to 1×10⁻⁶. -2 Pa, drying time is 2 hours, and after drying, immediately transfer to a desiccator for later use.

[0116] (2) Carbon film deposition by magnetron sputtering: The pretreated substrate was placed in a magnetron sputtering apparatus (medium frequency magnetron sputtering instrument, model: JGP-450), and the target material included high-purity graphite (purity 99.99%, size Φ60mm×5mm).

[0117] Turn on the vacuum system of the magnetron sputtering equipment. First, use a mechanical pump to evacuate the vacuum chamber to below 5 Pa, then start the molecular pump and continue evacuating to 5.0 × 10⁻⁶ Pa. -4 Pa.

[0118] Argon gas (99.999% purity) with a flow rate of 20 sccm was introduced into the vacuum chamber as the working gas for pre-sputtering treatment. The pre-sputtering power was 80W and the pre-sputtering time was 5 min. After the pre-sputtering was completed, the sputtering deposition process was carried out, with the sputtering power increased to 250W and the sputtering time 30 min. The argon gas flow rate and target-substrate distance were kept constant to form a carbon film with a thickness of 90 nm and a porosity of 20%. After the deposition was completed, the sputtering power supply and argon gas valve were turned off. The vacuum chamber was allowed to cool naturally to room temperature. The vacuum was then slowly released to atmospheric pressure. The vacuum chamber was opened and the carbon-coated substrate was removed. The target-substrate distance was 8 cm.

[0119] (3) MOF precursor solution impregnation to form intermediates: 2g of copper nitrate trihydrate (purity ≥99%), 0.2g of cobalt nitrate hexahydrate, and 0.2g of TiO2 particles were dissolved in 20mL of DMF and stirred until completely dissolved to prepare a metal salt solution. 0.4g of trimesic acid (purity ≥99%) was dissolved in 20mL of DMF and stirred until completely dissolved to obtain a ligand solution. The metal salt solution was slowly poured into the ligand solution, and stirring was continued for 20min to obtain a MOF precursor solution. The mass ratio of copper nitrate trihydrate to cobalt nitrate hexahydrate was 10:1, the mass ratio of copper nitrate trihydrate to TiO2 particles was 10:1, and the mass ratio of copper nitrate trihydrate to trimesic acid was 5:1.

[0120] A 50mL glass culture dish was used. The inner wall was wiped with ethanol and then dried to ensure no impurities remained. The carbon-coated substrate was placed flat and immersed in the MOF precursor solution, with the carbon film facing upwards. It was left to stand at 30℃ for 30 hours for immersion treatment. After immersion, the substrate edges were carefully picked up with tweezers, and the solution was slowly removed. The substrate was then placed in a vacuum oven for drying at 60℃ and a vacuum degree of 1×10⁻⁶. -2 Pa, drying time 12h, to obtain the intermediate.

[0121] (4) Pyrolysis forms a three-dimensional porous anode material: A tube furnace (model: OTF-1200X) is selected, and a corundum boat is placed inside the furnace chamber. The intermediate body is placed flat in the center of the corundum boat.

[0122] Introduce nitrogen gas at a flow rate of 50 sccm for 30 minutes to purge the air from the furnace. Then adjust the atmosphere in the furnace to a nitrogen atmosphere containing hydrogen (hydrogen volume fraction of 5%), while keeping the flow rate constant.

[0123] The heating rate was set to 10℃ / min, and the temperature was increased from room temperature to 800℃ for heat treatment, followed by isothermal heat treatment at a constant temperature for 2 hours. The temperature during the isothermal stage and the specific surface area of ​​the three-dimensional porous negative electrode material satisfy the following relationship: S = a × 800 2 +b×800+C, where S is the specific surface area of ​​the three-dimensional porous anode material, T is the temperature during the isothermal stage, and a, b and C are the fitting coefficient, temperature influence coefficient and constant term, respectively.

[0124] After completion, the heating power of the tubular furnace is turned off, the gas flow rate is kept constant, and the furnace is allowed to cool naturally to room temperature to obtain a three-dimensional porous anode material.

[0125] Example 5 The difference between this embodiment and embodiment 3 is that an activation treatment is performed after pyrolysis in step (4), the steps of which include: (a) Prepare a 7% KOH aqueous solution.

[0126] (b) The negative electrode material obtained in step (4) is placed in the KOH aqueous solution and left to stand at room temperature for 1 hour. Then, it is dehydrated at low temperature at 10°C. After that, it is dried in a forced-air oven at 90°C for 1.5 hours. After that, it is placed in a tube furnace with an air atmosphere and heated to 150°C at a heating rate of 5°C / min for 1 hour for activation reaction. After that, it is naturally cooled to room temperature and taken out. Finally, it is washed with deionized water until the pH of the washing solution is close to 7. Then, it is placed in an oven at 80°C for 6 hours to complete the activation.

[0127] The remaining preparation methods and parameters are consistent with those in Example 3.

[0128] Example 6 The difference between this embodiment and embodiment 4 is that in step (3), the amount of pyromellitic acid added is 1.2g, that is, the mass ratio of copper nitrate trihydrate to pyromellitic acid is 1.67:1.

[0129] The remaining preparation methods and parameters are consistent with those in Example 4.

[0130] Example 7 The difference between this embodiment and embodiment 4 is that in step (4), the heating rate is 15℃ / min.

[0131] The remaining preparation methods and parameters are consistent with those in Example 4.

[0132] Example 8 The difference between this embodiment and embodiment 4 is that in step (3), the amount of pyromellitic acid added is 1.5g, that is, the mass ratio of copper nitrate trihydrate to pyromellitic acid is 1.33:1.

[0133] The remaining preparation methods and parameters are consistent with those in Example 4.

[0134] Example 9 The difference between this embodiment and embodiment 4 is that the amount of copper nitrate trihydrate added in step (3) is adjusted so that the amount of Cu doping in the Cu-doped porous carbon framework is 0.2%.

[0135] The remaining preparation methods and parameters are consistent with those in Example 4.

[0136] Example 10 The difference between this embodiment and embodiment 4 is that the amount of copper nitrate trihydrate added in step (3) is adjusted so that the amount of Cu doping in the Cu-doped porous carbon framework is 15%.

[0137] The remaining preparation methods and parameters are consistent with those in Example 4.

[0138] Example 11 The difference between this embodiment and embodiment 4 is that the amount of cobalt nitrate hexahydrate added in step (3) is adjusted so that the loading of Co in the Cu-doped porous carbon framework is 0.2%.

[0139] The remaining preparation methods and parameters are consistent with those in Example 4.

[0140] Example 12 The difference between this embodiment and embodiment 4 is that the amount of cobalt nitrate hexahydrate added in step (3) is adjusted so that the loading of Co in the Cu-doped porous carbon framework is 15%.

[0141] The remaining preparation methods and parameters are consistent with those in Example 4.

[0142] Example 13 The difference between this embodiment and embodiment 4 is that the amount of TiO2 particles added in step (3) is adjusted so that the loading of TiO2 in the Cu-doped porous carbon framework is 0.2%.

[0143] The remaining preparation methods and parameters are consistent with those in Example 4.

[0144] Example 14 The difference between this embodiment and embodiment 4 is that the amount of TiO2 particles added in step (3) is adjusted so that the loading of TiO2 in the Cu-doped porous carbon framework is 20%.

[0145] The remaining preparation methods and parameters are consistent with those in Example 4.

[0146] Example 15 The difference between this embodiment and embodiment 4 is that the temperature in step (4) is 850°C during the constant temperature stage.

[0147] The remaining preparation methods and parameters are consistent with those in Example 4.

[0148] Comparative Example 1 The difference between this comparative example and Example 4 is that steps (3) and (4) are not performed, that is, the three-dimensional porous anode material is obtained only by magnetron sputtering.

[0149] The remaining preparation methods and parameters are consistent with those in Example 4.

[0150] Comparative Example 2 The difference between this comparative example and Example 4 is that step (2) is replaced by a coating method, that is, the carbon film on the substrate is prepared by coating with a coating machine.

[0151] The remaining preparation methods and parameters are consistent with those in Example 4.

[0152] Comparative Example 3 The difference between this comparative example and Example 4 is that in step (3), copper nitrate trihydrate is replaced with zinc nitrate hexahydrate.

[0153] The remaining preparation methods and parameters are consistent with those in Example 4.

[0154] Comparative Example 4 The difference between this comparative example and Example 4 is that TiO2 particles are not added in step (3), that is, the three-dimensional porous anode material does not contain TiO2.

[0155] The remaining preparation methods and parameters are consistent with those in Example 4.

[0156] Performance testing 1. The specific surface area, conductivity, and porosity of the three-dimensional porous anode materials provided in the above embodiments and comparative examples were tested.

[0157] The specific surface area test method is the BET test method, and the steps include: 1) Sampling and weighing: Weigh 300g of sample and put it into a special sample tube, and record the sample mass; connect the sample tube to the degassing station of the adsorption instrument, set the degassing temperature to 125℃, and the degassing time to 8h; 2) Instrument preparation and parameter setting: High-purity nitrogen (purity ≥99.999%) is selected as the adsorbate, and helium is used for volume calibration; the sample tube is immersed in a liquid nitrogen bath (77K) to keep the temperature stable during the test and ensure that the nitrogen adsorption behavior meets the standard conditions; the adsorption-desorption pressure range is set and the adsorption-desorption cycle mode is selected.

[0158] 3) Adsorption-desorption isotherm test: Helium gas is introduced into the system, and the dead volume between the sample tube and the sample is calculated based on the helium filling volume, which is used for subsequent adsorption amount correction; the nitrogen pressure in the system is gradually increased, and each time a set pressure point is reached, adsorption equilibrium is waited for (pressure stabilizes for 4 minutes), and the amount of nitrogen adsorbed on the sample at that pressure is recorded; after adsorption is completed, the system pressure is gradually reduced, and desorption equilibrium is waited for at each set pressure point, and the amount of desorption is recorded, finally obtaining the complete adsorption-desorption isotherm.

[0159] 4) Data processing and specific surface area calculation: The adsorption amount at each pressure point is corrected using dead volume data to obtain the actual nitrogen volume adsorbed by the sample; the specific surface area of ​​the sample is calculated by fitting the BET equation.

[0160] The conductivity was tested using the four-probe method, and the porosity was tested using the mercury porosimetry method.

[0161] II. Based on the three-dimensional porous negative electrode material provided in the above embodiments and comparative examples, a coin cell is fabricated. The preparation steps include: cutting the three-dimensional porous negative electrode material into electrode sheets of a specified size, using a lithium metal sheet as the counter electrode, Celgard 2400 as the separator, and a 1 mol / L LiPF6 EC / DMC / EMC (volume ratio 1:1:1) mixed solution as the electrolyte. The electrode sheets, separator, and counter electrode are assembled sequentially in an argon-protected glove box. After adding electrolyte for wetting, the cells are sealed to obtain a coin cell. After assembly, the cells are left to stand for 24 hours for subsequent electrochemical performance testing.

[0162] The energy density of the coin cells prepared above was tested, and the test steps included: a) Charging: Charge at a constant current of 1C until the battery voltage reaches 4.2V, then charge at a constant voltage until the current drops to 0.05C.

[0163] b) Discharge: Discharge at a constant current of 1C until the battery voltage drops to 2.5V.

[0164] c) Record data: Record data such as voltage, current, and time during the discharge process, and calculate the discharge energy.

[0165] d) Calculate energy density: Calculate the specific energy (Wh / kg) based on the discharge energy and battery mass.

[0166] The test results are shown in Table 1.

[0167] Table 1 analyze: As shown in Table 1, the three-dimensional porous anode material designed in this invention achieves integrated "conductive framework-porous structure" and synergistic enhancement of the porous carbon framework and functional components. Specifically, Cu doping in the porous carbon framework not only significantly improves the interfacial bonding strength and effectively suppresses component separation, but also enhances the mechanical stability of the carbon framework, fundamentally avoiding the problem of structural collapse during material use; the Co loading further improves the intrinsic conductivity of the material, ensuring a fast electron transport pathway; simultaneously, the introduction of TiO2 makes Ti 4+ This material can modulate the electronic structure of MOF derivatives, lower the lithium-ion migration barrier, alleviate volume expansion, and effectively suppress lithium dendrite formation. In summary, this material combines high specific surface area with structural stability, providing abundant active sites and lithium-ion storage space to ensure efficient mass transport, while also achieving excellent conductivity. It can be widely used in energy storage, catalysis, and sensing.

[0168] As can be seen from the comparison between Example 1 and Example 7, if the heating rate in step (4) is too high, it will easily lead to the rapid decomposition of the MOF organic ligand, generating a large amount of gas to impact the carbon skeleton, causing structural collapse, ultimately resulting in the destruction of active sites and reduction of specific surface area, obstruction of charge transport paths, and a significant decrease in electrochemical performance.

[0169] A comparison between Example 1 and Example 8 shows that if the mass ratio of hydrated copper nitrate to trimesic acid is too small, that is, if the amount of trimesic acid added is too large, then the excess organic ligand will leave amorphous carbon residue during the carbonization process, which will block the pore structure, reduce the conductivity of the material, and at the same time, the metal active sites will be coated, and the ion adsorption and catalytic activity will be weakened.

[0170] As can be seen from the comparison between Example 1 and Examples 9-10, if the amount of Cu doping in the Cu-doped porous carbon framework is too small, the number of active sites is insufficient, the electronic conductivity is poor, the pseudocapacitance contribution is low, and the rate performance and cycle stability are not good. If the amount of Cu doping in the Cu-doped porous carbon framework is too large, the Cu particles are prone to agglomeration and metal precipitation, which destroys the porous carbon framework structure, causes pore blockage, and triggers side reactions, reducing the cycle life of the material.

[0171] As can be seen from the comparison between Example 1 and Examples 11-12, if the Co loading in the Cu-doped porous carbon framework is too small, the bimetallic synergistic effect is not obvious, the redox active sites are insufficient, and the energy storage capacity and catalytic activity are low; if the Co loading in the Cu-doped porous carbon framework is too large, the Co particles will agglomerate severely, hindering ion diffusion, increasing electrode impedance, and easily causing a decrease in the stability of the material structure.

[0172] As can be seen from the comparison between Example 1 and Examples 13-14, if the TiO2 loading in the Cu-doped porous carbon framework is too small, the structural support and ion buffering effect of TiO2 are weak, the volume expansion problem of the material during charge and discharge is prominent, and the cycle stability is poor. If the TiO2 loading in the Cu-doped porous carbon framework is too large, the intrinsic conductivity of TiO2 is poor, and the excessive loading will reduce the overall electron conduction rate, hinder charge transport, and lead to a decrease in rate performance.

[0173] As can be seen from the comparison between Example 1 and Example 15, if the temperature in the isothermal stage in step (4) is too high, the degree of graphitization of the porous carbon skeleton is too high, the pore size shrinks, the active metal components sinter and agglomerate, and at the same time, some structures are destroyed by high temperature, the specific surface area and pore volume decrease, and the electrochemical performance decays.

[0174] As can be seen from the comparison between Example 1 and Comparative Example 1, if the three-dimensional porous anode material is obtained by magnetron sputtering alone, it is impossible to construct a multi-level interconnected porous structure. The number of active sites is scarce, and the interfacial bonding strength between the film and the substrate is insufficient, resulting in an extended ion diffusion path and obstructed charge transport. Ultimately, the electrochemical energy storage capacity, rate performance, and cycle stability of the material are significantly inferior to the composite modified material prepared in this invention.

[0175] As can be seen from the comparison between Example 1 and Comparative Example 2, if the carbon film is prepared by coating machine, the carbon film thickness uniformity is poor, the internal porosity is low and the pore connectivity is poor. At the same time, the interface compatibility between the coating layer and the porous skeleton is poor, and the film layer is prone to peeling and powdering during charge-discharge cycles, which greatly reduces the structural stability and cycle life of the material. In addition, the conductivity is also significantly reduced due to the defects in the pore structure.

[0176] As can be seen from the comparison between Example 1 and Comparative Example 3, if copper nitrate trihydrate is replaced with zinc nitrate hexahydrate, a carbon framework structure derived from Cu-based MOF cannot be formed. The active sites and electronic conduction advantages brought by Cu are missing. Furthermore, the pore structure and surface chemical properties of Zn-based MOF-derived carbon are difficult to match the energy storage requirements, resulting in slow redox reaction kinetics, insufficient pseudocapacitance contribution, and energy storage capacity and catalytic activity far lower than those of the Cu-doped system.

[0177] As can be seen from the comparison between Example 1 and Comparative Example 4, if the three-dimensional porous anode material does not contain TiO2, it lacks the rigid structural support and ion buffering effect of TiO2. During the charging and discharging process, the carbon skeleton is prone to significant volume expansion and contraction due to ion insertion and extraction, which in turn leads to structural collapse and pore blockage, resulting in the loss of active sites. The long-term cycling stability of the material is greatly reduced, and the ion transport efficiency is also reduced due to the lack of the synergistic effect of TiO2.

[0178] It should be noted that the present invention is illustrated through the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, additions of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A three-dimensional porous anode material, characterized in that, The three-dimensional porous anode material includes a Cu-doped porous carbon framework, wherein TiO2 and Co are loaded in the pores and on the surface of the Cu-doped porous carbon framework.

2. The three-dimensional porous anode material according to claim 1, characterized in that, The specific surface area of ​​the three-dimensional porous anode material is 1500-3000 m². 2 / g.

3. The three-dimensional porous anode material according to claim 1, characterized in that, In the Cu-doped porous carbon framework, the Cu doping amount is 1-13 wt%; And / or, in the Cu-doped porous carbon framework, the TiO2 loading is 0.5-10 wt%; And / or, the particle size D50 of the TiO2 is ≤50nm; And / or, in the Cu-doped porous carbon framework, the Co loading is 0.5-10 wt%.

4. The three-dimensional porous anode material according to claim 1, characterized in that, The Cu-doped porous carbon framework has a hierarchical porous structure composed of micropores, mesopores and macropores. And / or, the conductivity of the Cu-doped porous carbon framework is ≥1×10⁻⁶. 4 S / m; And / or, the porosity of the three-dimensional porous anode material is >25%; and / or, the thickness of the three-dimensional porous anode material is 0.5-10 μm.

5. The three-dimensional porous anode material according to claim 1, characterized in that, The surface of the Cu-doped porous carbon framework contains active functional groups, which include any one or a combination of at least two of the following: hydroxyl, carboxyl, amino, carbonyl, or epoxy groups.

6. A method for preparing a three-dimensional porous negative electrode material as described in any one of claims 1-5, characterized in that, The preparation method includes the following steps: A carbon film is deposited on a substrate using physical vapor deposition to obtain a carbon-coated substrate; The carbon-plated substrate is placed in an MOF precursor solution and impregnated to form an intermediate; wherein the MOF precursor solution includes a Cu source, a Co source, TiO2 particles and an organic ligand. The intermediate is subjected to heat treatment and cooling to form the three-dimensional porous anode material.

7. The preparation method according to claim 6, characterized in that, The physical vapor deposition method includes magnetron sputtering. And / or, the porosity of the carbon film is 8-60%; And / or, the thickness of the carbon film is 30-100 nm; And / or, the impregnation treatment is performed at a temperature of 25-40°C for a time of 24-36 hours; And / or, in the MOF precursor solution, the mass ratio of copper source to cobalt source is (8-10):1; And / or, in the MOF precursor solution, the mass ratio of copper source to TiO2 particles is (8-12):1; And / or, in the MOF precursor solution, the mass ratio of copper source to organic ligand is (1.5-5):1; And / or, the heat treatment includes a heating stage and a isothermal stage performed sequentially; the heating rate of the heating stage is 5-10℃ / min; the temperature of the isothermal stage is 750-800℃; and the holding time of the isothermal stage is 1.5-2.5h. And / or, the atmosphere for the heat treatment is an inert atmosphere containing hydrogen.

8. The preparation method according to claim 7, characterized in that, The temperature during the isothermal phase and the specific surface area of ​​the three-dimensional porous anode material satisfy the following relationship: S=a×T 2 +b×T+C, where S is the specific surface area of ​​the three-dimensional porous anode material, T is the temperature of the isothermal stage, a, b and C are the fitting coefficient, temperature influence coefficient and constant term respectively, and 750℃≤T≤800℃; And / or, after cooling, an activation treatment is further performed, the activation treatment steps including: The cooled negative electrode material is placed in an activation solution to carry out an activation reaction; The activating solution includes an aqueous solution of KOH with a mass fraction of 2-12%. The activation reaction is carried out at a temperature of 100-200℃ for 0.5-1.5 hours.

9. The preparation method according to claim 6, characterized in that, The preparation method includes the following steps: (1) Substrate pretreatment: The substrate is cleaned and dried to obtain a pretreated substrate; the substrate includes copper foil. (2) Carbon film deposition by magnetron sputtering: The pretreated substrate is placed in a magnetron sputtering apparatus and a vacuum is drawn; the target material in the magnetron sputtering apparatus includes graphite. A working gas is introduced into the vacuum chamber for pre-sputtering treatment. The pre-sputtering power is 70-90W, and the pre-sputtering time is 4-6 minutes. After pre-sputtering, a sputtering deposition process is performed, with the sputtering power increased to 100-300W and the sputtering time being 25-35 minutes, forming a carbon film with a thickness of 30-100 nm. After deposition, the substrate is naturally cooled to room temperature to obtain a carbon-coated substrate. The working gas includes argon, with a flow rate of 15-25 sccm and a target-substrate distance of 7-9 cm. (3) A metal salt solution is prepared by mixing Cu source, Co source, TiO2 particles and solvent; a ligand solution is prepared by mixing organic ligand and solvent; the metal salt solution and the ligand solution are mixed to obtain MOF precursor solution; wherein the organic ligand includes pyromellitic acid and / or 2-methylimidazole; The carbon-plated substrate is immersed in the MOF precursor solution and left to stand at 25-40°C for 24-36 hours for impregnation treatment. After the treatment, it is dried to obtain the intermediate. (4) Pyrolysis forms a three-dimensional porous anode material: The intermediate was placed in an inert atmosphere containing hydrogen, and the heating rate was set to 5-10℃ / min. The temperature was increased from room temperature to 750-800℃ for heat treatment, and then the temperature was kept constant for 1.5-2.5h for isothermal heat treatment. After completion, the material was naturally cooled to room temperature to obtain a three-dimensional porous anode material.

10. The application of a three-dimensional porous anode material as described in any one of claims 1-5 in the field of electrochemistry.

Images