A lithium metal composite negative electrode based on one-dimensional nano-reactors and a preparation method thereof

Abstract

The present application relates to a kind of lithium metal composite negative electrode based on one-dimensional nanoreactor and its preparation method.The lithium metal composite negative electrode based on one-dimensional nanoreactor of the present application is composed of metal lithium base and self-supporting nanofiber roll composite;Self-supporting nanofiber includes several one-dimensional nanoreactor;One-dimensional nanoreactor includes core layer and shell layer sleeved outside core layer, core layer is hollow layer with anion catalyst dispersed, and shell layer is polymer fiber.In addition, a method for preparing nanofiber with core-shell complex structure by coaxial directional double-nozzle electrospinning is also provided, hollow nanofiber is manufactured by calcining decomposition of core layer, and anion catalyst is dispersed and coated in the core layer of one-dimensional nanoreactor, which not only solves the poor cycle stability, thermal runaway and series safety problems of lithium metal battery, but also avoids unnecessary loss caused by additional electrochemical reaction of anion catalyst during charging and discharging.

Description

Technical Field

[0001] This invention relates to the field of lithium metal composite anode materials, specifically to a lithium metal composite anode based on a one-dimensional nanoreactor and its preparation method. Background Technology

[0002] Batteries, as an important electrochemical energy storage device, have undergone more than a century of development. To date, the energy density of graphite anodes in lithium-ion batteries has gradually approached its theoretical limit. The "Made in China 2025" plan, released by the State Council in 2015, proposed that the energy density of single-cell power batteries in my country should reach 400 Wh·kg⁻¹ by 2025. -1 It is expected to reach 500 Wh·kg by 2030. -1 The goal is to accelerate the realization of commercial batteries with higher energy density and lower production costs while maintaining battery safety and reliability. Lithium metal anodes, hailed as the "holy grail," are the most promising anode materials for high-energy battery systems.

[0003] However, during the lithium-ion plating / stripping process, the uneven deposition and unlimited volume expansion of lithium metal anodes can lead to uncontrolled lithium dendrite growth and SEI layer rupture, which can puncture the separator, causing internal short circuits, overheating, and even fire or explosion. Furthermore, the large specific surface area of ​​lithium dendrites exposes more active lithium to the electrolyte, exacerbating side reactions and resulting in the accumulation of large amounts of inactive lithium, leading to severe polarization. Therefore, one of the keys to constructing long-life, highly safe lithium metal secondary batteries is to suppress the dendritic growth of lithium metal.

[0004] Studies have shown that applying anionic catalysts to the separator of lithium metal batteries can effectively improve the electrochemical performance of lithium metal batteries. However, problems such as the consumption of anionic catalysts by unnecessary electrochemical reactions during battery cycling, the difficulty in scaling up the preparation process, and the high cost remain to be solved. Summary of the Invention

[0005] Based on this, the purpose of this invention is to provide a lithium metal composite anode based on a one-dimensional nanoreactor and its preparation method, which effectively alleviates the dendrite growth of lithium metal caused by the non-uniformity of lithium deposition and the infinite expansion of volume in the lithium metal anode, and reduces the consumption of anion catalysts during battery cycling.

[0006] A method for preparing a lithium metal composite anode based on a one-dimensional nanoreactor is disclosed, comprising a lithium metal substrate and self-supporting nanofibers rolled together; the self-supporting nanofibers include a plurality of one-dimensional nanoreactors; the one-dimensional nanoreactors include a core layer and a shell layer surrounding the core layer, wherein the core layer is a hollow layer with an anionic catalyst dispersed therein, and the shell layer is a polymer fiber.

[0007] This invention discloses a lithium metal composite anode based on a one-dimensional nanoreactor. An anionic catalyst is encapsulated within the core layer of the one-dimensional nanoreactor. When subjected to mechanical stress due to volume deformation, the anionic catalyst generates a built-in electric field, lowering the diffusion barrier of nearby lithium ions. Simultaneously, it captures anions, disrupting their electronic structure and forming an SEI layer rich in inorganic species such as LiF, Li3N, and Li2S. This inhibits lithium dendrite growth and solves the problems of poor cycle stability, thermal runaway, and a series of safety issues associated with lithium metal batteries. Furthermore, the one-dimensional nanoreactor shell provides physical protection for the separator while also isolating the anionic catalyst from the lithium substrate, preventing unnecessary losses due to additional electrochemical reactions during charge and discharge.

[0008] Furthermore, the anionic catalyst comprises one or more of barium titanate, palladium titanate, lead titanate, lead zirconate titanate, calcium silicate, aluminum silicate, lead niobate, strontium niobate, barium niobate, potassium niobate, sodium niobate, sodium metaniobate, potassium metaniobate, calcium germanate, barium germanate, titanium germanate, potassium tantalate, and bismuth aluminate.

[0009] The method for preparing the lithium metal composite anode based on a one-dimensional nanoreactor includes the following specific steps:

[0010] (1) Preparation of core layer precursor spinning solution: Disperse the anionic catalyst in the first solvent, then add polymer A and stir to mix evenly to obtain the core layer precursor spinning solution;

[0011] (2) Preparation of shell precursor spinning solution: Dissolve polymer B in a second solvent, stir, and mix evenly to obtain the shell precursor spinning solution.

[0012] (3) Preparation of precursor nanofibers: Using coaxial electrospinning technology, the core precursor spinning solution and the shell precursor spinning solution in steps (1) and (2) are respectively loaded into medical syringes and placed on a micro-injection pump. The micro-injection pump is started to push the core precursor spinning solution and the shell precursor spinning solution forward and are stretched from the double nozzle needle to the rotating receiving roller under the action of electric field force to obtain the precursor nanofibers;

[0013] (4) Preparation of self-supporting nanofibers: The precursor nanofibers obtained in step (3) are subjected to pre-oxidation and annealing to obtain the self-supporting nanofibers;

[0014] (5) Preparation of lithium metal composite anode: The self-supporting nanofibers obtained in step (4) are rolled and pressed with lithium sheets to form the lithium metal composite anode.

[0015] This invention utilizes coaxial directional dual-nozzle electrospinning to prepare nanofibers with complex core-shell structures, achieving precise control over different layers. Simultaneously, the core layer is calcined and decomposed to manufacture hollow nanofibers and disperse anionic catalysts within the core layer. The process is simple, green, and efficient, suitable for large-scale production, and has excellent application prospects.

[0016] Further, the specific rolling step of step (5) includes: first rolling the lithium sheet 0 to 10 times, and then stacking the self-supporting nanofibers obtained in step (4) together with the lithium sheet for rolling to form the lithium metal composite negative electrode with a thickness of 50 to 250 μm.

[0017] Further, in step (1), the mass percentage concentration of the anionic catalyst is 2-30 wt%, the mass percentage concentration of polymer A is 10-30 wt%, and the mass percentage concentration of polymer B in step (2) is 5-15 wt%.

[0018] Further, the polymer A includes one or more of polymethyl methacrylate, polystyrene, and polyvinylpyrrolidone.

[0019] Furthermore, the polymer B includes one or more of polyacrylonitrile, polypyrrole, polyamide, urea, melamine, and asphalt.

[0020] Furthermore, the first solvent and the second solvent include one or more of deionized water, ethanol, acetone, ethylene glycol, N,N-dimethylformamide, petroleum ether, and tetrahydrofuran.

[0021] Furthermore, the electrospinning process parameters in step (3) are as follows: the distance from the dual-nozzle needle to the rotating receiving roller is 15-20 cm, and the spinning solution injection speed is 1-2 mL / h. -1 The rotational speed of the rotating receiving roller is 300–500 r·min. -1 The voltage is 15-23kV, the ambient temperature is 20-50℃, and the ambient humidity is 10-40%.

[0022] Furthermore, in step (4), the pre-oxidation temperature is 270–300°C, the time is 1–2 h, and the heating rate is 1–5°C·min. -1 .

[0023] To better understand and implement this invention, the following detailed description is provided in conjunction with the accompanying drawings. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the lithium metal composite anode based on a one-dimensional nanoreactor as described in this invention.

[0025] Figure 2 This is a flowchart illustrating the preparation method of the lithium metal composite anode based on a one-dimensional nanoreactor according to the present invention. Detailed Implementation

[0026] The terminology used in the embodiments of this application is for the purpose of describing specific embodiments only and is not intended to limit the embodiments of this application. It should be understood that the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of the embodiments of this application.

[0027] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the embodiments of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. Furthermore, in the description of this application, unless otherwise stated, “a plurality” means two or more.

[0028] The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0029] It should be understood that the embodiments of this application are not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope.

[0030] Please see Figure 1 The present invention discloses a lithium metal composite anode based on a one-dimensional nanoreactor, which is formed by rolling and composite of a lithium metal substrate and self-supporting nanofibers. The self-supporting nanofibers include a plurality of one-dimensional nanoreactors. Each one-dimensional nanoreactor includes a core layer and a shell layer surrounding the core layer. The core layer is a hollow layer with an anionic catalyst dispersed therein, and the shell layer is a polymer fiber. The mass percentage concentration of the anionic catalyst is 2-30 wt%. The anionic catalyst includes one or more of barium titanate, palladium titanate, lead titanate, lead zirconate titanate, calcium silicate, aluminum silicate, lead niobate, strontium niobate, barium niobate, potassium niobate, sodium niobate, sodium metaniobate, potassium metaniobate, calcium germanate, barium germanate, titanium germanate, potassium tantalate, and bismuth aluminate.

[0031] Please see Figure 2 The method for preparing the lithium metal composite anode based on a one-dimensional nanoreactor according to the present invention includes the following specific steps:

[0032] (1) Preparation of core layer precursor spinning solution: Disperse the anionic catalyst in the first solvent, then add polymer A with a mass percentage concentration of 10-30 wt%, stir at room temperature for 6-12 h, and mix evenly to obtain the core layer precursor spinning solution; the polymer A includes one or more of polymethyl methacrylate, polystyrene, and polyvinylpyrrolidone.

[0033] (2) Preparation of shell precursor spinning solution: Dissolve polymer B with a mass percentage concentration of 5-15 wt% in a second solvent, stir at room temperature for 6-12 h, and mix evenly to obtain the shell precursor spinning solution; the polymer B includes one or more of polyacrylonitrile, polypyrrole, polyamide, urea, melamine, and asphalt.

[0034] The first solvent and the second solvent include one or more of deionized water, ethanol, acetone, ethylene glycol, N,N-dimethylformamide, petroleum ether, and tetrahydrofuran;

[0035] (3) Preparation of precursor nanofibers: Using coaxial electrospinning technology, the core precursor spinning solution and the shell precursor spinning solution from steps (1) and (2) are respectively loaded into medical syringes and placed on a micro-injection pump. The micro-injection pump is started to push the core precursor spinning solution and the shell precursor spinning solution forward and, under the action of an electric field, are stretched from the dual-nozzle needle to the rotating receiving roller to obtain precursor fibers; the distance from the dual-nozzle needle to the rotating receiving roller is 15-20 cm, and the injection speed of the spinning solution is 1-2 mL·h. -1 The rotational speed of the rotating receiving roller is 300–500 r·min. -1 The voltage is 15-23kV, the ambient temperature is 20-50℃, and the ambient humidity is 10-40%.

[0036] (4) Preparation of self-supporting nanofibers: The precursor nanofibers obtained in step (3) are placed in a muffle furnace for pre-oxidation and annealing treatment, wherein the pre-oxidation temperature is 270-300℃, the time is 1-2h, and the heating rate is 1-5℃·min. -1 The self-supporting nanofibers are obtained.

[0037] (5) Preparation of lithium metal composite anode: The self-supporting nanofibers obtained in step (4) are rolled together with lithium sheets in a glove box to form a lithium metal composite anode.

[0038] Example 1

[0039] A method for preparing a lithium metal composite anode based on a one-dimensional nanoreactor includes the following specific steps:

[0040] (1) Preparation of core layer precursor spinning solution: 0.1g barium titanate (BaTiO3) was dispersed in 4mL N,N-dimethylformamide (DMF), and then 1.2g polymethyl methacrylate (PMMA) was added. The mixture was stirred at room temperature for 6h and mixed evenly to obtain the core layer precursor spinning solution.

[0041] (2) Preparation of shell precursor spinning solution: Dissolve 0.25g of polyacrylonitrile (PAN) in 5mL of N,N-dimethylformamide (DMF), stir at room temperature for 6h, and mix evenly to obtain the shell precursor spinning solution.

[0042] (3) Preparation of precursor nanofibers: Using coaxial electrospinning technology, the core precursor spinning solution and the shell precursor spinning solution from steps (1) and (2) are respectively loaded into medical syringes and placed on a micro-injection pump. The micro-injection pump is started to push the core precursor spinning solution and the shell precursor spinning solution forward and, under the action of an electric field, are stretched from the dual-nozzle needle to the rotating receiving roller to obtain the precursor nanofibers; wherein, the process parameters of electrospinning are: the distance from the dual-nozzle needle to the rotating receiving roller is 15 cm, and the injection speed of the spinning solution is 1 mL·h. -1 The rotating receiving roller rotates at a speed of 400 r·min. -1 The voltage is 20kV, the ambient temperature is 30℃, and the ambient humidity is 10%.

[0043] (4) Preparation of self-supporting nanofibers: The precursor nanofibers obtained in step (3) were placed in a muffle furnace for pre-oxidation and annealing treatment at a temperature of 270°C for 2 hours at a heating rate of 2°C·min. -1 A self-supporting nanofiber was obtained, consisting of a hollow core layer with dispersed barium titanate (BaTiO3) and a shell layer of polyacrylonitrile (PAN).

[0044] (5) Preparation of lithium metal composite anode: In the glove box, the 150μm lithium sheet is rolled one after another until the thickness is reduced to 50μm. Then the self-supporting nanofibers obtained in step (4) are stacked together with the lithium sheet and rolled to make the lithium metal composite anode with a thickness of 100μm.

[0045] Example 2

[0046] A method for preparing a lithium metal composite anode based on a one-dimensional nanoreactor includes the following specific steps:

[0047] (1) Preparation of core layer precursor spinning solution: 0.1g barium titanate (BaTiO3) was dispersed in 4mL N,N-dimethylformamide (DMF), and then 0.43g polymethyl methacrylate (PMMA) was added. The mixture was stirred at room temperature for 6h and mixed evenly to obtain the core layer precursor spinning solution.

[0048] (2) Preparation of shell precursor spinning solution: Dissolve 0.84g of polyacrylonitrile (PAN) in 5mL of N,N-dimethylformamide (DMF), stir at room temperature for 6h, and mix evenly to obtain the shell precursor spinning solution.

[0049] (3) Preparation of precursor nanofibers: Using coaxial electrospinning technology, the core precursor spinning solution and the shell precursor spinning solution from steps (1) and (2) are respectively loaded into medical syringes and placed on a micro-injection pump. The micro-injection pump is started to push the core precursor spinning solution and the shell precursor spinning solution forward and, under the action of an electric field, are stretched from the dual-nozzle needle to the rotating receiving roller to obtain the precursor nanofibers; wherein, the process parameters of electrospinning are: the distance from the dual-nozzle needle to the rotating receiving roller is 15 cm, and the injection speed of the spinning solution is 1 mL·h. -1 The rotating receiving roller rotates at a speed of 400 r·min. -1 The voltage is 20kV, the ambient temperature is 30℃, and the ambient humidity is 10%.

[0050] (4) Preparation of self-supporting nanofibers: The precursor nanofibers obtained in step (3) were placed in a muffle furnace for pre-oxidation and annealing treatment at a temperature of 280°C for 2 hours at a heating rate of 2°C·min. -1 A self-supporting nanofiber was obtained, consisting of a hollow core layer with dispersed barium titanate (BaTiO3) and a shell layer of polyacrylonitrile (PAN).

[0051] (5) Preparation of lithium metal composite anode: Same as in Example 1.

[0052] Example 3

[0053] A method for preparing a lithium metal composite anode based on a one-dimensional nanoreactor includes the following specific steps:

[0054] (1) Preparation of core layer precursor spinning solution: 1.2g barium titanate (BaTiO3) was dispersed in 4mL N,N-dimethylformamide (DMF), and then 2.1g polymethyl methacrylate (PMMA) was added. The mixture was stirred at room temperature for 12h and mixed evenly to obtain the core layer precursor spinning solution.

[0055] (2) Preparation of shell precursor spinning solution: Dissolve 0.5g of polyacrylonitrile (PAN) in 5mL of N,N-dimethylformamide (DMF), stir at room temperature for 12h, and mix evenly to obtain the shell precursor spinning solution.

[0056] (3) Preparation of precursor nanofibers: Using coaxial electrospinning technology, the core precursor spinning solution and the shell precursor spinning solution from steps (1) and (2) are respectively loaded into medical syringes and placed on a micro-injection pump. The micro-injection pump is started to push the core precursor spinning solution and the shell precursor spinning solution forward and, under the action of an electric field, are stretched from the dual-nozzle needle to the rotating receiving roller to obtain the precursor nanofibers; wherein, the process parameters of electrospinning are: the distance from the dual-nozzle needle to the rotating receiving roller is 18 cm, and the injection speed of the spinning solution is 1 mL·h. -1 The rotating receiving roller rotates at a speed of 400 r·min. -1 The voltage is 20kV, the ambient temperature is 30℃, and the ambient humidity is 20%.

[0057] (4) Preparation of self-supporting nanofibers: The precursor nanofibers obtained in step (3) were placed in a muffle furnace for pre-oxidation and annealing treatment at a temperature of 280°C for 2 hours at a heating rate of 2°C·min. -1 A self-supporting nanofiber was obtained, consisting of a hollow core layer with dispersed barium titanate (BaTiO3) and a shell layer of polyacrylonitrile (PAN).

[0058] (5) Preparation of lithium metal composite anode: Same as in Example 1.

[0059] Example 4

[0060] A method for preparing a lithium metal composite anode based on a one-dimensional nanoreactor includes the following specific steps:

[0061] (1) Preparation of core layer precursor spinning solution: Same as in Example 3.

[0062] (2) Preparation of shell precursor spinning solution: Same as in Example 3.

[0063] (3) Preparation of precursor nanofibers: Using coaxial electrospinning technology, the core precursor spinning solution and the shell precursor spinning solution from steps (1) and (2) are respectively loaded into medical syringes and placed on a micro-injection pump. The micro-injection pump is started to push the core precursor spinning solution and the shell precursor spinning solution forward and, under the action of an electric field, are stretched from the dual-nozzle needle to the rotating receiving roller to obtain the precursor nanofibers; wherein, the process parameters of electrospinning are: the distance from the dual-nozzle needle to the rotating receiving roller is 20 cm, and the injection speed of the spinning solution is 2 mL·h. -1 The rotating receiving roller rotates at a speed of 500 r·min. -1 The voltage is 23kV, the ambient temperature is 50℃, and the ambient humidity is 10%.

[0064] (4) Preparation of self-supporting nanofibers: The precursor nanofibers obtained in step (3) were placed in a muffle furnace for pre-oxidation and annealing treatment at a temperature of 280°C for 2 hours at a heating rate of 2°C·min. -1 A self-supporting nanofiber was obtained, consisting of a hollow core layer with dispersed barium titanate (BaTiO3) and a shell layer of polyacrylonitrile (PAN).

[0065] (5) Preparation of lithium metal composite anode: Same as in Example 1.

[0066] Example 5

[0067] A method for preparing a lithium metal composite anode based on a one-dimensional nanoreactor includes the following specific steps:

[0068] (1) Preparation of core layer precursor spinning solution: 0.3g barium titanate (BaTiO3) was dispersed in 2mL N,N-dimethylformamide (DMF), and then 0.2g polymethyl methacrylate (PMMA) was added. The mixture was stirred at room temperature for 6h and mixed evenly to obtain the core layer precursor spinning solution.

[0069] (2) Preparation of shell precursor spinning solution: Dissolve 0.5g of polyacrylonitrile (PAN) in 3mL of N,N-dimethylformamide (DMF), stir at room temperature for 6h, and mix evenly to obtain the shell precursor spinning solution.

[0070] (3) Preparation of precursor nanofibers: Using coaxial electrospinning technology, the core precursor spinning solution and the shell precursor spinning solution from steps (1) and (2) are respectively loaded into medical syringes and placed on a micro-injection pump. The micro-injection pump is started to push the core precursor spinning solution and the shell precursor spinning solution forward and, under the action of an electric field, are stretched from the dual-nozzle needle to the rotating receiving roller to obtain the precursor nanofibers; wherein, the process parameters of electrospinning are: the distance from the dual-nozzle needle to the rotating receiving roller is 15 cm, and the injection speed of the spinning solution is 1 mL·h. -1 The rotating receiving roller rotates at a speed of 300 r / min. -1 The voltage is 15kV, the ambient temperature is 50℃, and the ambient humidity is 10%.

[0071] (4) Preparation of self-supporting nanofibers: The precursor nanofibers obtained in step (3) were placed in a muffle furnace for pre-oxidation and annealing treatment at a temperature of 280°C for 2 hours at a heating rate of 2°C·min. -1 A self-supporting nanofiber was obtained, consisting of a hollow core layer with dispersed barium titanate (BaTiO3) and a shell layer of polyacrylonitrile (PAN).

[0072] (5) Preparation of lithium metal composite anode: Same as in Example 1.

[0073] Example 6

[0074] A method for preparing a lithium metal composite anode based on a one-dimensional nanoreactor includes the following specific steps:

[0075] (1) Preparation of core layer precursor spinning solution: 1.2g barium titanate (BaTiO3) was dispersed in 8mL N,N-dimethylformamide (DMF), and then 2.4g polymethyl methacrylate (PMMA) was added. The mixture was stirred at room temperature for 12h and mixed evenly to obtain the core layer precursor spinning solution.

[0076] (2) Preparation of shell precursor spinning solution: Dissolve 1g of polyacrylonitrile (PAN) in 10mL of N,N-dimethylformamide (DMF), stir at room temperature for 12h, and mix evenly to obtain the shell precursor spinning solution.

[0077] (3) Preparation of precursor nanofibers: Using coaxial electrospinning technology, the core precursor spinning solution and the shell precursor spinning solution from steps (1) and (2) are respectively loaded into medical syringes and placed on a micro-injection pump. The micro-injection pump is started to push the core precursor spinning solution and the shell precursor spinning solution forward and, under the action of an electric field, are stretched from the dual-nozzle needle to the rotating receiving roller to obtain the precursor nanofibers; wherein, the process parameters of electrospinning are: the distance from the dual-nozzle needle to the rotating receiving roller is 18 cm, and the injection speed of the spinning solution is 1 mL·h. -1 The rotating receiving roller rotates at a speed of 400 r·min. -1 The voltage is 20kV, the ambient temperature is 30℃, and the ambient humidity is 40%.

[0078] (4) Preparation of self-supporting nanofibers: The precursor nanofibers obtained in step (3) were placed in a muffle furnace for pre-oxidation and annealing treatment at a temperature of 280°C for 2 hours at a heating rate of 5°C·min. -1 A self-supporting nanofiber was obtained, consisting of a hollow core layer with dispersed barium titanate (BaTiO3) and a shell layer of polyacrylonitrile (PAN).

[0079] (5) Preparation of lithium metal composite anode: In a glove box, the self-supporting nanofibers obtained in step (4) are directly stacked together with 150μm lithium sheets and rolled to form the lithium metal composite anode with a thickness of 250μm.

[0080] Example 7

[0081] A method for preparing a lithium metal composite anode based on a one-dimensional nanoreactor includes the following specific steps:

[0082] (1) Preparation of core layer precursor spinning solution: Same as in Example 3.

[0083] (2) Preparation of shell precursor spinning solution: Same as in Example 3.

[0084] (3) Preparation of precursor nanofibers: Same as in Example 3.

[0085] (4) Preparation of self-supporting nanofibers: The precursor nanofibers obtained in step (3) were placed in a muffle furnace for pre-oxidation and annealing treatment at a temperature of 300℃ for 1 h at a heating rate of 1℃·min. -1 A self-supporting nanofiber was obtained, consisting of a hollow core layer with dispersed barium titanate (BaTiO3) and a shell layer of polyacrylonitrile (PAN).

[0086] (5) Preparation of lithium metal composite anode: Same as in Example 3.

[0087] Comparative Example 1

[0088] A method for preparing a lithium metal composite anode includes the following specific steps:

[0089] (1) Preparation of core layer precursor spinning solution: Dissolve 1.2g of polymethyl methacrylate (PMMA) in 4mL of N,N-dimethylformamide (DMF), stir at room temperature for 12h, and mix evenly to obtain the core layer precursor spinning solution.

[0090] (2) Preparation of shell precursor spinning solution: Dissolve 0.5g of polyacrylonitrile (PAN) in 5mL of N,N-dimethylformamide (DMF), stir at room temperature for 12h, and mix evenly to obtain the shell precursor spinning solution.

[0091] (3) Preparation of precursor nanofibers: Using coaxial electrospinning technology, the core precursor spinning solution and the shell precursor spinning solution from steps (1) and (2) are respectively loaded into medical syringes and placed on a micro-injection pump. The micro-injection pump is started to push the core precursor spinning solution and the shell precursor spinning solution forward and, under the action of an electric field, are stretched from the dual-nozzle needle to the rotating receiving roller to obtain the precursor nanofibers; wherein, the process parameters of electrospinning are: the distance from the dual-nozzle needle to the rotating receiving roller is 18 cm, and the injection speed of the spinning solution is 1 mL·h. -1 The rotating receiving roller rotates at a speed of 400 r·min. -1 The voltage is 20kV, the ambient temperature is 30℃, and the ambient humidity is 20%.

[0092] (4) Preparation of self-supporting nanofibers: The precursor nanofibers obtained in step (3) were placed in a muffle furnace for pre-oxidation and annealing treatment at a temperature of 280°C for 2 hours at a heating rate of 2°C·min. -1 A self-supporting nanofiber was obtained, consisting of a hollow core layer with dispersed barium titanate (BaTiO3) and a shell layer of polyacrylonitrile (PAN).

[0093] (5) Preparation of lithium metal composite anode: In the glove box, the 150μm lithium sheet is rolled one after another until the thickness is reduced to 50μm. Then the self-supporting nanofibers obtained in step (4) are stacked together with the lithium sheet and rolled to make the lithium metal composite anode with a thickness of 100μm.

[0094] Comparative Example 2

[0095] A method for preparing a lithium metal anode includes the following specific steps: in a glove box, a 150μm lithium sheet is rolled and pressed one after another to form a lithium metal anode with a thickness of 100μm.

[0096] The negative electrodes from Examples 1-7 and Comparative Examples 1-2 were assembled into symmetrical cells: the prepared negative electrodes were cut and used as counter electrodes and working electrodes to assemble symmetrical cells. The button cell model was CR2032, the separator was a polypropylene microporous membrane Celgard2400, and the electrolyte was LiTFSI / DOL+DME (V / V = 1:1) containing 2wt% LiNO3. The assembled symmetrical cells were subjected to electrochemical performance testing on a Newway testing system under the test conditions of 1 mA·cm⁻¹. -2 1mAh·cm -2 The results are shown in Table 1.

[0097] Table 1. Test results of symmetric cells

[0098]

[0099] The negative electrodes of Examples 1-7 and Comparative Examples 1-2 were assembled with lithium iron phosphate to form full cells: Lithium iron phosphate, superconducting carbon black (SuperP), and polyvinylidene fluoride (PVDF) were mixed in a mass ratio of 8:1:1, and an appropriate amount of N-methylpyrrolidone (NMP) was added. The mixture was thoroughly stirred into a paste, and the uniformly mixed slurry was evenly coated onto aluminum foil using a spatula. The foil was then dried in a vacuum drying oven at 60°C for 12 hours and cut to serve as the positive electrode for the lithium metal battery. In a glove box, the negative electrode was cut to prepare the full cell. The battery model was CR2032, the separator was a polypropylene microporous membrane Celgard2400, and the electrolyte was LiTFSI / DOL+DME (V / V = 1:1) containing 2wt% LiNO3. The electrochemical performance of the assembled symmetrical battery was tested on the Newway testing system, and the results are shown in Table 2.

[0100] Table 2. Full Battery Test Results

[0101]

[0102] As shown in Table 1, the initial deposition nucleation overvoltage (mV) of Comparative Examples 1-2 is significantly higher than that of Examples 1-7 of this application. This may lead to uneven deposition of lithium metal, forming lithium dendrite structures, which increases the risk of internal short circuits and affects battery safety and cycle stability. Furthermore, the significantly higher initial deposition nucleation overvoltage (mV) of Comparative Examples 1-2 results in uneven chemical reactions within the battery, leading to battery degradation and deterioration. It also increases internal resistance, affecting energy conversion efficiency and ultimately reducing battery performance and lifespan. Compared to Comparative Examples 1-2, the symmetrical batteries of Examples 1-7 of this invention exhibit lower polarization voltage and longer cycle life, indicating that the composite negative electrode can effectively enhance the diffusion rate of ions at the electrode interface, alleviate polarization during lithium deposition, and simultaneously mitigate lithium dendrite growth.

[0103] As shown in Table 2, the discharge specific capacity (mAh / g) and capacity retention rate (%) of Comparative Examples 1-2 after 500 cycles at 1C are significantly lower than those of Examples 1-7 of this application. This indicates that the cycle stability and lifespan of the full cells assembled with the negative electrodes of Comparative Examples 1-2 and lithium iron phosphate are poor. Compared with Comparative Examples 1-2, Examples 1-7 of this invention exhibit slower capacity decay and better cycle stability under 1C conditions. This is mainly due to the high ion diffusion rate at the interface of the composite negative electrode, resulting in fast ion transport and strong mechanical properties of the formed SEI film. Furthermore, the one-dimensional nanoreactor shell protects the anion catalyst, preventing unnecessary loss of the anion catalyst during charging and discharging, thereby extending the lifespan of the lithium metal battery.

[0104] This invention discloses a lithium metal composite anode based on a one-dimensional nanoreactor. It utilizes coaxial directional dual-nozzle electrospinning to prepare nanofibers with a complex core-shell structure. Simultaneously, the core layer is calcined and decomposed to create hollow nanofibers, dispersing anionic catalyst within the core layer. The anionic catalyst is then encapsulated within the core layer of the one-dimensional nanoreactor. During battery cycling, a stable SEI layer rich in inorganic species such as LiF, Li3N, and Li2S is formed, thereby improving ion diffusion rate, inhibiting lithium dendrite growth, and enhancing battery performance and safety. Furthermore, the one-dimensional nanoreactor shell provides physical protection for the separator while also isolating the anionic catalyst from the lithium substrate, preventing unnecessary losses due to additional electrochemical reactions during charge and discharge. The preparation method of this lithium metal composite anode based on a one-dimensional nanoreactor is simple, green, efficient, suitable for large-scale production, and has excellent application prospects.

[0105] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and the present invention also intends to include these modifications and variations.

Claims

1. A method for preparing a lithium metal composite anode based on one-dimensional nanoreactor, characterized in that: the lithium metal composite anode based on one-dimensional nanoreactor is composed of a metal lithium substrate and a self-supporting nanofiber roll composite; the self-supporting nanofiber comprises a plurality of one-dimensional nanoreactors; the one-dimensional nanoreactor comprises a core layer and a shell layer sleeved outside the core layer, the core layer is a hollow layer with an anion catalyst dispersed therein, and the shell layer is a polymer fiber; the preparation method comprises the following specific steps: (1) preparation of a core layer precursor spinning solution: an anion catalyst is dispersed in a first solvent, then a polymer A is added and stirred to obtain the core layer precursor spinning solution; (2) preparation of a shell layer precursor spinning solution: a polymer B is dissolved in a second solvent, stirred and mixed uniformly to obtain the shell layer precursor spinning solution; (3) preparation of a precursor nanofiber: the core layer precursor spinning solution and the shell layer precursor spinning solution in steps (1) and (2) are respectively filled into medical syringes and placed on a microsyringe pump, the microsyringe pump is started to push the core layer precursor spinning solution and the shell layer precursor spinning solution to be stretched to a rotating receiving roller under the action of an electric field force through a double-nozzle needle, thereby obtaining the precursor nanofiber; and (5) preparation of a lithium metal composite anode: the self-supporting nanofiber obtained in step (4) is roll-pressed with a lithium sheet to form the lithium metal composite anode. The anion catalyst comprises one or more of barium titanate, palladium titanate, lead titanate, lead zirconium titanate, calcium silicate, aluminum silicate, lead niobate, strontium niobate, barium niobate, potassium niobate, sodium niobate, sodium metaniobate, potassium metaniobate, calcium germanate, barium germanate, titanium germanate, potassium tantalate, bismuth aluminate. The specific rolling step of step (5) comprises: first, roll-pressing the lithium sheet 0-10 times, then stacking the self-supporting nanofiber obtained in step (4) and the lithium sheet together for roll-pressing to form the lithium metal composite anode with a thickness of 50-250 μm. The mass percentage concentration of the anion catalyst in step (1) is 2-30 wt%; the mass percentage concentration of the polymer A is 10-30 wt%; and the mass percentage concentration of the polymer B in step (2) is 5-15 wt%. The polymer A comprises one or more of polymethyl methacrylate, polystyrene and polyvinylpyrrolidone. The polymer B comprises one or more of polyacrylonitrile, polypyrrole and polyamide. (4) Preparation of the self-supporting nanofiber: the precursor nanofiber obtained in step (3) is subjected to pre-oxidation and annealing treatment to obtain the self-supporting nanofiber; the pre-oxidation temperature is 270-300°C, the time is 1-2h, and the heating rate is 0.5-2°C / min ; The first solvent and the second solvent comprise one or more of deionized water, ethanol, acetone, ethylene glycol, N, N-dimethylformamide, petroleum ether and tetrahydrofuran.

2. The method for preparing a lithium metal composite anode based on a one-dimensional nanoreactor according to claim 1, characterized in that: ​ 3. The method of claim 1 or 2, wherein the method comprises: ​ 4. The method of claim 1-2, wherein the method comprises: ​ 5. The method of claim 1-2, wherein the method comprises: ​ 6. The method of claim 1-2, wherein the method is characterized by: ​ 7. The method of claim 1-2, wherein the method comprises: ​ 8. The method of claim 1-2, wherein the method comprises: The electrospinning process parameters in step (3) are as follows: the distance from the dual-nozzle needle to the rotating receiving roller is 15-20 cm, and the spinning solution injection speed is... The rotational speed of the rotating receiving roller is The voltage is 15~23kV, the ambient temperature is 20~50℃, and the ambient humidity is 10~40%.

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