Preparation method and application of lithium-philic hollow carbon nanofiber material

Abstract

The invention provides a preparation method and application of a lithium-philic hollow carbon nanofiber material, and belongs to the technical field of lithium metal negative electrode materials. The preparation method comprises the following steps: adding a functional non-solvent organic matter into a low-boiling-point organic solvent, adding a carbon source high-molecular polymer into a high-boiling-point organic polar solvent, and mixing the two solutions to obtain a mixed solution; dissolving a lithium-loving metal salt in the mixed solution, and stirring and dissolving to obtain a precursor solution; carrying out electrostatic spinning on the precursor solution, initiating non-solvent-induced phase separation by utilizing a double-diffusion effect of a solvent and a non-solvent, and forming a hollow structure in situ, so as to prepare a hollow carbon nanofiber precursor membrane; and then sequentially carrying out drying, pre-oxidation treatment and high-temperature carbonization treatment to obtain the lithium-loving hollow carbon nanofiber material. The material can induce uniform deposition of lithium and effectively buffer volume expansion, the preparation method is simple, convenient and efficient, the fiber structure can be regulated and controlled by controlling the solution proportion, and the application requirement of a lithium metal battery is met.

Description

Technical Field

[0001] This invention relates to the field of preparation technology of three-dimensional conductive carbon nanofibers modified with lithium metal anodes, specifically to a method for preparing and applying lithium-loving hollow carbon nanofiber materials. Background Technology

[0002] Lithium metal has an extremely high theoretical specific capacity (3860 mAh g). −1 With its low electrochemical reduction potential (-3.04V), lithium metal anodes are considered one of the most promising anode materials. However, in practical applications, lithium metal anodes face significant volume changes during charge and discharge. These volume changes can damage the inherent SEI film, and uneven current distribution can lead to lithium dendrite growth and dead lithium formation. Therefore, directly using lithium metal anodes may result in lower cycle performance and safety risks such as thermal runaway, severely hindering the commercial application of lithium metal batteries. In recent decades, researchers have proposed various strategies, such as artificial SEI, electrolyte additives, and solid polymer electrolytes. However, these methods cannot fundamentally solve the problems of uneven lithium deposition and volume expansion of lithium metal anodes. Therefore, new methods must be used to modify lithium metal batteries.

[0003] Three-dimensional host structures can effectively guide the uniform deposition of lithium metal. Among them, hollow carbon nanofibers are considered an ideal lithium host framework due to their high conductivity and adjustable internal space. However, the mainstream methods for preparing hollow carbon nanofiber materials have inherent defects: the template method relies on the preset template shape and size, making it difficult to design and control complex or continuously changing structures (such as pore size and chamber morphology), and the post-processing template removal step is cumbersome; the coaxial electrospinning method for constructing hollow fiber structures is limited by the precision machining of complex nozzles (coaxial / concentric nozzles) and the synergistic control of dual-channel solutions, resulting in a narrow range of control over fiber wall thickness and diameter, complex processes, and difficulty in large-scale production.

[0004] Therefore, there is an urgent need in this field to develop a simple process and a highly tunable hollow carbon fiber preparation method to construct a lithium metal anode material that can effectively adapt to volume changes and uniformly guide lithium ion deposition. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing and applying lithium-loving hollow carbon nanofiber materials, thereby solving the problems of existing technologies. This invention involves adding a functionalized non-solvent organic compound to a low-boiling-point organic solvent and a carbon source polymer to a high-boiling-point organic polar solvent. The two solutions are mixed to obtain a mixed solution, and a lithium-loving metal salt is dissolved in the mixed solution. The mixture is stirred to obtain a precursor solution. Then, through electrospinning, the non-solvent phase separation is initiated by the dual diffusion effect of the solvent and non-solvent, forming a hollow structure in situ, resulting in a fiber precursor film. Finally, after drying, pre-oxidation, and high-temperature carbonization, the lithium-loving hollow carbon nanofiber material is obtained. This invention utilizes the non-solvent phase separation mechanism of electrospinning to obtain large, stable hollow structures without the need for templates or complex nozzles. The hollow cavity inside the fiber preferentially confines lithium metal within the cavity, not only providing a larger volume to alleviate lithium expansion but also improving the uniform deposition of lithium, effectively mitigating the volume expansion and electrode polarization of the lithium metal anode. Furthermore, the modification with the lithium-loving metal salt further improves the uniform nucleation and deposition of lithium ions, meeting the development needs of lithium batteries.

[0006] On one hand, the present invention provides a method for preparing a lithiophilic hollow carbon nanofiber material, comprising the following steps: Functionalized non-solvent organic compounds are added to a low-boiling-point organic solvent to prepare solution A; carbon source polymer powder is added to a high-boiling-point organic polar solvent and stirred to dissolve to prepare solution B, which is then mixed with solution A to obtain mixed solution C; a lithiophilic metal salt is dissolved in mixed solution C and stirred to dissolve to obtain precursor solution D; precursor solution D is electrospun to obtain a hollow carbon nanofiber precursor film; the obtained carbon nanofiber film is successively dried, pre-oxidized, and carbonized at high temperature to obtain a lithiophilic hollow carbon nanofiber material.

[0007] In fact, the method provided by this invention employs the principle of solvent-free phase separation. Compared to traditional template methods and coaxial spinning methods, it utilizes the spontaneous double diffusion effect within the solution to form a hollow structure through phase separation. This eliminates the need for templates or complex nozzles. By precisely controlling the solvent / non-solvent ratio, it overcomes the limitations of template methods (constrained by template shape and size, making it difficult to achieve complex or continuously changing structures) and the limitations of coaxial spinning methods (limited range of wall thickness and diameter control). Furthermore, solvent-free phase separation overcomes the problems of complex processes, high costs, and difficulty in scaling up, simplifying multi-step preparation into a single step, significantly reducing equipment requirements and operational complexity.

[0008] Optionally, the functionalized non-solvent organic material includes at least one of tetraethyl orthosilicate and tetrabutyl titanate. Specifically, the functionalized non-solvent organic material undergoes phase separation during electrospinning through a dual diffusion effect with the solvent to form a hollow structure. In subsequent processes, it decomposes and transforms in situ into the corresponding nano-metal oxide, which is uniformly dispersed on the outer wall and inner surface of the hollow carbon nanofiber, thus endowing the fiber with additional adsorption sites and mechanical reinforcement effects.

[0009] Optionally, the low-boiling-point organic solvent includes at least one of ethanol, isopropanol, acetone, diethyl ether, and ethyl acetate. Specifically, the low-boiling-point organic solvent rapidly solidifies during electrospinning to form a fiber shell, while the high-boiling-point polar solvent undergoes a controllable phase separation process with the non-solvent, forming a large number of regular hollow structures.

[0010] Optionally, the high-boiling-point organic polar solvent includes at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide.

[0011] Optionally, the mass ratio of the functionalized non-solvent organic compound to the low-boiling-point organic solvent in solution A is (0.2-0.3):1.

[0012] Optionally, the lithium-loving metal salt includes at least one of zinc nitrate, tin acetate, silver nitrate, nickel nitrate, and cobalt nitrate.

[0013] Optionally, the mass fraction of the lithium-loving metal salt in the mixed solution C is 1.5%-2%.

[0014] In practice, lithiophilic metal salts are directly dissolved in a precursor solution. In subsequent steps, the lithiophilic metal salts are thermally reduced to metal particles and embedded into the hollow carbon nanofiber framework formed by a non-solvent-induced phase separation method. Specifically, compared to traditional template methods and coaxial spinning methods, its advantage lies in the fact that during electrospinning and carbonization, the non-solvent-induced phase separation mechanism allows metal particles to be generated in situ and uniformly embedded in the pore walls of the carbon fiber framework, resulting in a stronger bond. Furthermore, the metal particles can be selectively enriched on the inner or outer surface through design. This helps overcome the problems of uneven distribution and easy detachment of functional components, induces preferential deposition of lithium metal inside the hollow fiber cavity and uniform deposition on the outer surface, and significantly improves the lithium storage behavior of the lithium storage space, especially inside the hollow cavity, greatly limiting the formation of lithium dendrites.

[0015] Optionally, the carbon source polymer powder includes at least one of polyacrylonitrile, polyvinylpyrrolidone, and polyvinylidene fluoride.

[0016] Optionally, during the mixing process to obtain mixed solution C, the mass ratio of the carbon source polymer powder to the remaining components in mixed solution C is (0.2-0.3):1.

[0017] Optionally, during the process of dissolving the precursor solution D by stirring, the stirring is carried out on a magnetic stirrer with a speed controlled at 400-600 r / min and a stirring time of 8-12 h.

[0018] Optionally, the electrospinning is performed using a needle-type spinning device, with the needle being either a No. 22 or No. 23 needle. The parameters for electrospinning include a positive voltage of 15-17kV, a negative voltage of 1.35-1.45kV, a distance of 22-24cm between the injector and the receiver, a feed speed of 0.05-0.07mm / min, a temperature control of 25-30℃, a humidity control of 40%-60%, and a spinning time of 3-5h.

[0019] Optionally, the drying is carried out at 80-100℃, and the drying time is controlled at 10-12h.

[0020] Optionally, the pre-oxidation treatment is carried out in air at 220-280℃, with the heating rate controlled at 2-3℃ / min and the pre-oxidation time being 1.5-3h.

[0021] Optionally, the high-temperature carbonization treatment includes: carbonizing the pre-oxidized carbon nanofiber membrane at 700-900℃ in an inert atmosphere for 1-3 hours; wherein the inert atmosphere is at least one of nitrogen and argon, and the gas flow rate is controlled at 80-120 mL / min.

[0022] On the other hand, the present invention provides the application of lithium-loving hollow carbon nanofiber materials prepared by any of the above methods in lithium metal electrodes.

[0023] Due to the adoption of the above solution, the beneficial effects of the present invention are as follows: (1) The preparation method provided by this invention adopts a non-solvent-induced phase separation method, which utilizes the spontaneous double diffusion effect inside the solution to induce phase separation and form a hollow structure. It does not require a template or a complex nozzle. By precisely controlling the non-solvent / solvent ratio, it can overcome the problems of template method being limited by template shape and size and difficult to achieve complex or continuously changing structures; and the limited range of wall thickness and diameter control in coaxial spinning method. This preparation method overcomes the problems of complex process, high cost and difficulty in large-scale production, simplifies the multi-step preparation into one step, and greatly reduces the equipment threshold and operation difficulty.

[0024] (2) The functionalized non-solvent used in the preparation method of the present invention decomposes and is converted in situ into the corresponding nano-metal oxides and is uniformly dispersed on the outer wall and inner surface of the hollow carbon nanofibers in the subsequent process, giving the fibers additional adsorption sites and mechanical enhancement effect; in addition, the method of the present invention introduces lithium-loving nanoparticles, which can provide more lithium-loving sites for hollow carbon nanofibers, induce uniform nucleation of lithium metal, especially inside the hollow channel, reduce nucleation overpotential, and significantly improve lithium deposition / stripping efficiency.

[0025] (3) The lithium-loving hollow carbon nanofiber material prepared by the method of the present invention has a large specific surface area and internal hollow cavity, which can significantly reduce the local current density, effectively accommodate and confine lithium metal, provide buffer space for volume changes during deposition / stripping, and effectively suppress the overall expansion of the electrode.

[0026] (4) The lithium-loving hollow carbon nanofiber material prepared by the method of the present invention, under the synergistic effect of the above-mentioned structural advantages, jointly induces the uniform deposition of lithium metal, greatly improves the cycle stability and rate performance of the negative electrode, effectively alleviates the problems of volume expansion, electrode polarization and lithium dendrite growth, and significantly improves the safety and long cycle life of lithium metal batteries. Attached Figure Description

[0027] Figure 1 A flowchart of a method for preparing a lithiophilic hollow carbon nanofiber material provided by the present invention; Figure 2 This is a SEM image of the lithiophilic hollow carbon nanofiber material prepared in Example 1 of the present invention; Figure 3 The half-cell assembled from the lithiophilic hollow carbon nanofiber material prepared in Example 1 of this invention and the materials prepared in the parallel control group, at 1 mA cm⁻¹ −2 Current density and 1mAh cm −2 CE test diagram at capacity; Figure 4 The half-cell assembled from the lithiophilic hollow carbon nanofiber material prepared in Example 1 of this invention and the materials prepared in its parallel comparative group showed an efficiency of 2 mA cm⁻¹. −2 Current density and 1mAh cm −2 CE test diagram at capacity; Figure 5 The half-cell assembled from the lithiophilic hollow carbon nanofiber material prepared in Example 1 of this invention and the materials prepared in the parallel control group showed an efficiency of 3 mA cm⁻¹. −2 Current density and 1mAh cm −2 CE test diagram at capacity; Figure 6The symmetric battery assembled from the lithiophilic hollow carbon nanofiber material prepared in Example 1 of this invention and the materials prepared in its parallel comparative group, achieved a speed of 1 mA cm⁻¹. −2 Current density and 1mAh cm −2 Test graph at capacity; Figure 7 This is a SEM image of the lithiophilic hollow carbon nanofiber material prepared in Example 2 of the present invention; Figure 8 The half-cell assembled from the lithiophilic hollow carbon nanofiber material prepared in Example 2 of this invention and the materials prepared in the parallel comparative group, showed an efficiency of 1 mA cm⁻¹. −2 Current density and 1mAh cm −2 CE test diagram at capacity. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, 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. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art. The present invention will be specifically described below with reference to the embodiments, but the implementation and protection scope of the present invention are not limited to the following embodiments.

[0029] Examples 1 and 2 provide a method for preparing a lithiophilic hollow carbon nanofiber material, the preparation method being carried out according to... Figure 1 The flowchart shown is followed.

[0030] Example 1: Preparation of a lithium-loving hollow carbon nanofiber coated with silver nanoparticles 0.4 g of tetraethyl orthosilicate was added to 1.6 g of anhydrous ethanol to obtain solution A (the mass ratio of tetraethyl orthosilicate to anhydrous ethanol was 0.25:1); 0.6 g of polyvinylpyrrolidone (Mw=1300000) was dissolved in 0.73 g of N-N-dimethylformamide and stirred thoroughly to obtain solution B. Solution A and solution B were mixed to obtain mixed solution C (wherein the mass ratio of polyvinylpyrrolidone to the remaining components in mixed solution C was 0.22:1); 0.05 g of silver nitrate powder was added to mixed solution C to obtain precursor solution D (the mass fraction of silver nitrate in precursor solution D was 1.5%). Precursor solution D was placed in a magnetic stirrer and stirred at a speed of 400 r / min for 12 h.

[0031] Precursor solution D was drawn into a 5 mL syringe, and electrospinning was performed using a No. 22 needle. During the spinning process, the spinning voltage was adjusted to a positive voltage of 16 kV and a negative voltage of 1.5 kV, the receiving distance was 22 cm, the feed rate was controlled at 0.05 mm / min, the temperature was 25 ℃, and the humidity was 55%. The electrospinning time was 3.5 h.

[0032] The spun raw yarn film was dried for 10 hours at 80°C. After drying, it underwent pre-oxidation treatment in air at 250°C with a heating rate of 3°C / min and a holding time of 3 hours.

[0033] The pre-oxidized membrane was carbonized under the protection of high-purity argon gas at a flow rate of 120 mL / min at 750 °C for 2 h to obtain three-dimensional lithiophilic hollow carbon nanofibers coated with silver nanoparticles.

[0034] Parallel comparison group of Example 1: Carbon fiber without low-boiling-point solvent: The difference from the preparation of lithiophilic hollow carbon fiber in Example 1 is that anhydrous ethanol is not added to solution A, while the other operations remain the same, and carbon fiber without low-boiling-point solvent is prepared.

[0035] Nonfunctionalized nonsolvent-free carbon fiber: The difference from the preparation of lithiophilic hollow carbon fiber in Example 1 is that tetraethyl orthosilicate is not added to solution A, while the other operations remain the same, and nonfunctionalized nonsolvent-free carbon fiber is prepared.

[0036] Lithophilic hollow carbon fiber: The difference from the preparation of lithophilic hollow carbon fiber in Example 1 is that silver nitrate powder is not added. The obtained mixed solution C is used as the precursor solution for electrospinning. The rest of the operation is the same, and lithophilic hollow carbon fiber is prepared.

[0037] Example 2: Preparation of a lithium-loving hollow carbon nanofiber coated with zinc oxide nanoparticles 0.6 g of tetrabutyl titanate was added to 2.5 g of acetone (the mass ratio of tetrabutyl titanate to acetone was 0.24:1) to obtain solution A; 1 g of polyacrylonitrile (Mw=600000) was dissolved in 1.07 g of N-N-dimethylacetamide and stirred thoroughly to obtain solution B. Solution A and solution B were mixed to obtain mixed solution C (wherein the mass ratio of polyacrylonitrile to the remaining components in mixed solution C was 0.24:1); 0.093 g of zinc nitrate powder was added to mixed solution C to obtain precursor solution D (the mass fraction of zinc nitrate powder in precursor solution D was 1.8%). The precursor solution was placed in a magnetic stirrer and stirred at a speed of 500 r / min for 10 h.

[0038] Precursor solution D was drawn into a 5ml syringe, and electrospinning was performed using a No. 23 needle. During the spinning process, the spinning voltage was adjusted to a positive voltage of 17kV and a negative voltage of 1.45kV, the receiving distance was 24cm, the feed rate was controlled at 0.06mm / min, the temperature was 26℃, and the humidity was 50%. The electrospinning time was 3h.

[0039] The spun raw yarn film was dried for 12 hours at 90°C. After drying, it underwent pre-oxidation treatment in air at 270°C with a heating rate of 2°C / min and a holding time of 2 hours.

[0040] The pre-oxidized membrane was carbonized under the protection of high-purity argon gas at a flow rate of 90 mL / min at 800 °C for 1.5 h to obtain three-dimensional lithiophilic hollow carbon nanofibers coated with zinc oxide nanoparticles.

[0041] Parallel comparison group of Example 2: Low-boiling-point solvent-free carbon fiber: The difference from the preparation of lithiophilic hollow carbon fiber in Example 2 is that acetone is not added to solution A, while the other operations remain the same, and low-boiling-point solvent-free carbon fiber is prepared.

[0042] Nonfunctionalized solvent-free carbon fiber: The difference from the preparation of lithiophilic hollow carbon fiber in Example 2 is that tetrabutyl titanate is not added to solution A, while the other operations remain the same, and nonfunctionalized solvent-free carbon fiber is prepared.

[0043] Lithophilic hollow carbon fiber: The difference from the preparation of lithophilic hollow carbon fiber in Example 2 is that zinc nitrate powder is not added. The resulting mixed solution C is used as the precursor solution for electrospinning. All other operations are kept the same to prepare lithophilic hollow carbon fiber.

[0044] The performance of the lithiophilic hollow carbon nanofiber material prepared in Example 1 and the materials prepared in the parallel control group were characterized and tested.

[0045] (1) Material structure characterization The morphology of the lithiophilic hollow carbon nanofiber material prepared in Example 1 was observed using scanning electron microscopy (SEM). The results are shown in the figure. Figure 2 ,from Figure 2 The carbon nanofibers can be seen to be fibrous, and the prepared carbon nanofibers have a hollow feature, with the hollow interior containing lithium-loving silver nanoparticles.

[0046] (2) Half-cell performance evaluation To assemble a half-cell containing lithium-philic hollow nanofibers, the lithium-philic hollow carbon nanofibers prepared in Example 1 were first cut into electrodes with a radius of 14 mm, and then assembled into a 2032 coin cell. The assembly sequence from bottom to top was: negative electrode shell, gasket, electrolyte (35 μL), lithium sheet, electrolyte (35 μL), separator, electrolyte (35 μL), electrode, gasket, spring sheet, and positive electrode shell. The electrolyte used was LS009 type. Coulombic efficiency tests were performed on the assembled battery, and the results were obtained at 1 mA cm⁻¹. −2 Current density and 1mAh cm −2 Capacity, 2mA cm −2 Current density and 1mAh cm −2 Capacity and 3mA cm −2 Current density and 1mAhcm −2 Capacity testing was conducted. The lithiophilic hollow carbon nanofiber material was replaced with the low-boiling-point solvent-free carbon fiber, non-functionalized non-solvent carbon fiber, and non-lithiophilic hollow carbon fiber materials prepared in the parallel control group of Example 1, respectively, and half-cells were assembled for evaluation.

[0047] Results: The half-cells assembled from the lithiophilic hollow carbon nanofiber material prepared in Example 1 and the materials prepared in the parallel control group showed a performance of 1 mA cm⁻¹. −2 Current density and 1mAh cm −2 See CE test for capacity. Figure 3 , at 2mA cm −2 Current density and 1mAh cm −2 See CE test for capacity. Figure 4 , at 3mA cm −2 Current density and 1mAh cm −2 See CE test for capacity. Figure 5 .Depend on Figures 3 to 5 It is known that half-cells containing lithiophilic hollow carbon nanofibers have excellent reversibility and stable cycling performance, while half-cells composed of non-lithiophilic hollow carbon fibers have inferior performance compared to half-cells assembled from lithiophilic hollow carbon fibers. Furthermore, the number of cycles required to maintain high efficiency decreases with increasing current density. The performance of half-cells assembled from non-functionalized non-solvent carbon fibers and carbon fibers without low-boiling-point solvents is far lower than that of half-cells assembled from lithiophilic hollow carbon fibers.

[0048] (3) Performance evaluation of symmetric cells The assembled symmetrical battery was subjected to constant current charge-discharge testing, and the steps were as follows: First, the half-cell was assembled according to the steps in (2) above, and the constant current charge-discharge test was performed at a current density of 1 mA cm⁻¹. −2After deposition at the current density for 10 hours, the electrodes were disassembled in a glove box using a disassembly mold. The disassembled electrodes were then immersed in dimethyl carbonate to remove the electrolyte. After drying, they were assembled into a symmetrical cell in the following order: negative electrode shell, gasket, electrolyte (35 μL), electrode, electrolyte (35 μL), separator, electrolyte (35 μL), electrode, gasket, spring, and positive electrode shell. The electrolyte used was LS009 type. The assembled symmetrical cell was then subjected to a 1 mA cm⁻¹ test. −2 Current density and 1mAh cm −2 Capacity test.

[0049] Results: The symmetric cells assembled from the lithiophilic hollow carbon nanofiber material prepared in Example 1 and the materials prepared in the parallel control group achieved a performance of 1 mA cm⁻¹. −2 Current density and 1mAh cm −2 See capacity test Figure 6 .from Figure 6 It can be seen that the symmetric battery containing lithiophilic hollow carbon nanofiber material has a low and stable overpotential without fluctuation in the voltage curve within 2000h of constant current charge-discharge, and the assembled battery has excellent cycle performance. The symmetric battery without lithiophilic hollow carbon fiber material has a larger voltage fluctuation amplitude and its cycle performance is lower than that of the battery assembled with lithiophilic hollow carbon fiber. The symmetric batteries assembled with nonfunctionalized non-solvent carbon fiber and non-low boiling point solvent carbon fiber are extremely unstable and fail rapidly in a short time, which is far lower than that of the battery assembled with lithiophilic hollow carbon fiber.

[0050] The performance of the lithiophilic hollow carbon nanofiber material prepared in Example 2 and the materials prepared in the parallel control group were characterized and tested.

[0051] (1) Material structure characterization The morphology of the lithiophilic hollow carbon nanofiber material prepared in Example 2 was observed using scanning electron microscopy (SEM). The results are shown in the figure. Figure 7 ,from Figure 7 The carbon nanomaterials can be seen as fibrous, and the prepared carbon nanofibers have a hollow structure.

[0052] (2) Half-cell performance evaluation To assemble a half-cell containing lithium-philic hollow nanofiber material, the lithium-philic hollow carbon nanofiber membrane prepared in Example 2 was first cut into electrodes with a radius of 14 mm, and then assembled into a 2032 type coin cell. The assembly sequence from bottom to top was: negative electrode shell, gasket, electrolyte (35 μL), lithium sheet, electrolyte (35 μL), separator, electrolyte (35 μL), electrode, gasket, spring sheet, and positive electrode shell. The electrolyte used was LS009 type. Coulombic efficiency tests were performed on the assembled battery, and the results were obtained at 1 mA cm⁻¹. −2 Current density and 1mAh cm −2Capacity testing was conducted. The lithiophilic hollow carbon nanofiber material was replaced with the low-boiling-point solvent-free carbon fiber, non-functionalized non-solvent carbon fiber, and non-lithiophilic hollow carbon fiber materials prepared in the parallel control group of Example 2, respectively, and half-cells were assembled for evaluation.

[0053] Results: The half-cells assembled from the lithiophilic hollow carbon nanofiber material prepared in Example 2 and the materials prepared in the parallel control group showed a performance of 1 mA cm⁻¹. −2 Current density and 1mAh cm −2 See CE test for capacity. Figure 8 ,Depend on Figure 8 It is known that half-cells containing lithium-loving hollow carbon nanofiber materials have excellent reversibility and stable cycling performance.

[0054] While embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations fall within the scope and spirit of the invention as set forth in the claims. Furthermore, the invention described herein may have other embodiments and can be implemented or carried out in various ways.

Claims

1. A method for producing a lithium-philic hollow carbon nanofiber material, characterized by, The method comprises the following steps: functional non-solvent organic matter is added to a low-boiling organic solvent to prepare solution A; carbon source polymer powder is added to a high-boiling organic polar solvent to prepare solution B, and then solution A is mixed with solution B to obtain mixed solution C; a lithium-philic metal salt is dissolved in mixed solution C to prepare precursor solution D; The precursor solution D is electrospun to obtain a carbon nanofiber raw yarn film containing hollows; the carbon nanofiber film is sequentially subjected to drying, pre-oxidation treatment and high-temperature carbonization treatment to obtain the lithium-philic hollow carbon nanofiber material.

2. The production method according to claim 1, characterized by, The functional non-solvent organic matter comprises at least one of tetraethyl orthosilicate and tetrabutyl titanate; and / or the low-boiling organic solvent comprises at least one of ethanol, isopropyl alcohol, acetone, diethyl ether and ethyl acetate; and / or the high-boiling organic polar solvent comprises at least one of N-N dimethylformamide, N-N dimethylacetamide, N-methyl pyrrolidone and dimethyl sulfoxide; and / or the mass ratio of the functional non-solvent organic matter to the low-boiling organic solvent in solution A is (0.2-0.3):

1.

3. The preparation method according to claim 1, characterized in that, The lithium-philic metal salt comprises at least one of zinc nitrate, tin acetate, silver nitrate, nickel nitrate and cobalt nitrate; and / or the mass fraction of the lithium-philic metal salt in the precursor solution D is 1.5%-2%.

4. The method of claim 1, wherein, The carbon source polymer powder comprises at least one of polyacrylonitrile, polyvinylpyrrolidone and polyvinylidene fluoride; and / or the mass ratio of the carbon source polymer powder to the remaining components in the mixed solution C is (0.2-0.3):1 during the mixing to obtain the mixed solution C; and / or the stirring is performed on a magnetic stirrer, the stirring speed is controlled to be 400-600 r / min, and the stirring time is 8-12 h.

5. The preparation method according to claim 1, characterized in that, The electrospinning is performed by using a needle tube type spinning device, and the needle head is one of a 22-gauge needle head and a 23-gauge needle head; the parameters for the electrospinning include: a positive voltage of 15-17 kV, a negative voltage of 1.35-1.45 kV, a distance between a pusher and a receiver of 22-24 cm, a push speed of 0.05-0.07 mm / min, a temperature control of 25-30 DEG C, a humidity control of 40%-60%, and a spinning time of 3-5 h.

6. The method of claim 1, wherein, The drying is performed at 80-100 DEG C, and the drying time is controlled to be 10-12 h; and / or the pre-oxidation treatment is performed in air at 220-280 DEG C, the heating rate is controlled to be 2-3 DEG C / min, and the pre-oxidation time is 1.5-3 h.

7. The preparation method according to claim 1, characterized in that, The high-temperature carbonization treatment comprises: carbonizing the carbon nanofiber film after the pre-oxidation treatment in an inert atmosphere at 700-900 DEG C, and the carbonization time is 1-3 h; wherein the inert atmosphere is at least one of nitrogen and argon, and the gas flow rate is controlled to be 80-120 mL / min.

8. Application of the lithium-philic hollow carbon nanofiber material prepared by the method of any one of claims 1 to 7 to a lithium metal electrode.

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