A fully ordered nanofiber structure battery with homogeneous reaction and its preparation method and application

Abstract

The present invention belongs to the technical field of quasi-solid-state lithium metal batteries, and more specifically, relates to a fully ordered nanofiber structure battery with a homogeneous reaction, and its preparation method and application. The present invention prepares an ordered porous carbon hollow tube-based lithium metal composite electrode by using lithiophilic modified ordered porous carbon hollow tubes, and then combines it with an ordered sulfide nanofiber membrane and an electrolyte polymerized in situ within an ordered nanofiber skeleton to form a quasi-solid-state lithium metal battery, thereby establishing continuous, uniform and rapid lithium ion transmission throughout the battery. This design effectively improves the lithium ion extraction / insertion kinetics, ensures the uniform distribution of lithium ion concentration and electric field, promotes uniform reaction of the anode and cathode, thereby achieving uniform deposition and stripping of metallic lithium, and maximizing the utilization rate of the cathode material, thereby significantly improving the cycle life of the battery.

Description

Technical Field

[0001] The present invention belongs to the technical field of quasi-solid-state lithium metal batteries, and more specifically relates to a fully ordered nanofiber structure battery with a homogeneous reaction, and a preparation method and application thereof. Background Art

[0002] With the rapid development of renewable energy and electric vehicles, the demand for high-efficiency and high-energy-density storage technologies continues to increase. -1 Due to its high theoretical energy density, sulfur is considered a strong contender for the next generation of energy storage devices. In addition, sulfur has the advantages of low cost, abundant reserves and environmental protection. However, traditional organic liquid electrolytes (LEs) used in lithium-sulfur batteries have serious safety issues such as volatility and flammability, which increase the possibility of leakage and fire hazards. To address these problems, quasi-solid-state polymer electrolytes have been developed as a safer alternative. Quasi-solid-state polymer electrolytes provide high ionic conductivity, excellent interfacial compatibility, and strong mechanical strength can inhibit lithium dendrite growth and improve battery stability and life.

[0003] Quasi-solid-state lithium-sulfur batteries face several practical challenges, including the poor conductivity of sulfur and lithium sulfide (Li2S), the shuttle effect caused by the dissolution and diffusion of lithium polysulfides (LiPSs), significant volume changes during charge and discharge, and uneven lithium deposition and dissolution. To address these challenges, various attempts have been made, such as using functional nanofibers as separators to mitigate the shuttle effect of LiPSs, applying sulfided polyacrylonitrile as an alternative to elemental sulfur cathodes to reduce the formation of LiPSs, and developing three-dimensional porous carbon-based materials as lithium metal hosts to buffer volume changes and inhibit dendrite growth. Although these strategies have partially addressed some of the challenges of quasi-solid-state lithium-sulfur batteries, significant limitations still exist. In particular, the slow, discontinuous, and uneven flux of lithium ions leads to large concentration gradients along the longitudinal direction of the electrode, inducing non-uniform reactions during battery cycling. This can lead to uneven lithium deposition and stripping, reduce the utilization of active materials, and ultimately affect the battery's cycle life.

[0004] In order to mitigate the inhomogeneous reaction, it is essential to optimize the distribution of lithium ion flux within the battery. Recent studies have shown that highly ordered nanofibers enhance the uniformity of lithium ion flux and electric field distribution. For example, the ordered Li 6.4 La3Zr2Al 0.2 O 12(LLZO) nanofibers are integrated into a polymer matrix to create an efficient lithium ion transport network while providing excellent mechanical stability when used as a separator. This design significantly improves the uniformity of electron and ion transport, effectively inhibiting the growth of lithium dendrites. In addition, highly ordered structures have also been used to improve the electron / ion transport properties and mechanical flexibility of anode materials, thereby improving high-speed performance and cycle durability. These studies have shown that the addition of ordered nanofibers can significantly improve mechanical properties, establish fast and uniform lithium ion flux paths, alleviate concentration polarization, and effectively promote homogeneous reactions. However, it is worth noting that in these studies, only certain battery components used aligned nanofibers. Components lacking such an ordered structure will undoubtedly compromise the uniformity of lithium ion transport, resulting in uneven distribution of electric and stress fields within the battery, thereby reducing the overall performance of the battery.

[0005] Therefore, it is necessary to provide a new structure for quasi-solid-state lithium metal batteries that can promote uniform transmission of lithium ions and uniform distribution of electric fields throughout the battery, thereby promoting the occurrence of homogeneous reactions. Summary of the Invention

[0006] The purpose of the present invention is to provide a fully ordered nanofiber structure battery with homogeneous reaction, and its preparation method and application, so as to solve the problems existing in the above-mentioned prior art. The fully ordered nanofiber structure material provided by the present invention as a battery component can promote rapid and uniform lithium ion transmission, make the lithium ion concentration more evenly distributed throughout the battery, thereby promoting the occurrence of homogeneous reaction.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] One of the technical solutions of the present invention is to provide a method for preparing lithiophilic-modified ordered porous carbon hollow tubes, comprising the following steps:

[0009] dissolving the carbon-forming polymer and the metal salt in N,N-dimethylformamide (DMF) to obtain a precursor solution;

[0010] The precursor solution is electrospun to obtain an ordered nanofiber membrane containing a metal salt;

[0011] After a metal organic framework layer is in situ grown on the ordered nanofiber membrane containing metal salts, the lithium-philic modified ordered porous carbon hollow tubes are obtained through carbonization etching.

[0012] Furthermore, the carbon-forming polymer includes at least one of polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), polystyrene (PS) and polyvinyl pyrrolidone (PVP).

[0013] Furthermore, the metal salt includes at least one of zinc acetate, cobalt acetate, silver acetate, nickel acetate and copper acetate.

[0014] Furthermore, the concentration of the carbon-forming polymer in the precursor solution is 8-12 wt %, and the concentration of the metal salt is 2-5 wt %.

[0015] Furthermore, the electrospinning parameters are: voltage 15-22 kV, flow rate 0.3-0.6 mL·h -1 , receiver distance 10 ~ 20cm, humidity controlled at ~ 40%, drum speed 2000 ~ 3000r·min -1 .

[0016] Furthermore, the step of in-situ growing the metal organic framework layer includes:

[0017] The ordered nanofiber membrane containing metal salt is placed in a 2-methylimidazole solution to in-situ grow a metal organic framework on the surface of the fiber membrane.

[0018] Furthermore, the carbonization etching atmosphere is nitrogen atmosphere, the temperature is 700-1100°C, the time is 2-6h, and the heating rate is 2-5°C·min -1 .

[0019] The second technical solution of the present invention is to provide a lithiophilic modified ordered porous carbon hollow tube obtained by the above preparation method.

[0020] The lithiophilic modification in the lithiophilic-modified ordered porous carbon hollow tubes of the present invention comprises a metal-nitrogen coordination compound, metal nanoparticles or metal oxides, wherein the metal-nitrogen coordination compound is selected from at least one of Zn-N / O, Co-N, Ag-N and Ni-N, the metal nanoparticles are selected from at least one of zinc, cobalt, silver and nickel, and the metal oxide is selected from at least one of zinc oxide, copper oxide, tin dioxide and titanium dioxide.

[0021] Furthermore, the diameter of the lithiophilic modified ordered porous carbon hollow tube is 50 to 400 nm.

[0022] The third technical solution of the present invention: provides an ordered porous carbon hollow tube-based lithium metal composite electrode, wherein the ordered porous carbon hollow tube-based lithium metal composite electrode comprises the above-mentioned lithiophilic modified ordered porous carbon hollow tube and metallic lithium.

[0023] The fourth technical solution of the present invention is to provide a method for preparing the above-mentioned ordered porous carbon hollow tube-based lithium metal composite electrode, comprising the following steps:

[0024] The lithiophilic modified ordered porous carbon hollow tube is brought into contact with molten metallic lithium, and the ordered porous carbon hollow tube-based lithium metal composite electrode is obtained after infiltration.

[0025] Furthermore, the temperature of the molten metallic lithium is 180-350°C.

[0026] Furthermore, the contact time is 5 to 30 seconds.

[0027] The fifth technical solution of the present invention: provides an application of the above-mentioned lithiophilic modified ordered porous carbon hollow tubes or ordered porous carbon hollow tube-based lithium metal composite electrodes in quasi-solid-state lithium metal batteries.

[0028] Technical solution six of the present invention: provides a lithium metal-sulfur battery, comprising: a positive electrode, a negative electrode and an electrolyte; the positive electrode is an ordered sulfurized nanofiber membrane; the negative electrode is the above-mentioned ordered porous carbon hollow tube-based lithium metal composite electrode; the electrolyte is an electrolyte in situ polymerized within the ordered nanofiber skeleton.

[0029] The lithium metal-sulfur battery prepared by the present invention has a fully ordered arrangement structure and is composed of fully ordered nanofiber battery components. It can promote the uniform transmission of lithium ions and uniform distribution of the electric field inside the entire battery, thereby promoting the occurrence of homogeneous reactions, which is beneficial to the uniform deposition and stripping of lithium metal and improves the utilization rate of active substances. It has extremely high application value in the field of high-performance quasi-solid-state lithium metal batteries.

[0030] Furthermore, the preparation steps of the ordered sulfurized nanofiber membrane include:

[0031] Using polymer as solute and N,N-dimethylformamide as solvent, ordered nanofiber membranes were obtained by electrospinning.

[0032] The ordered nanofiber membrane is mixed with a sulfur source and subjected to a sulfurization treatment to obtain the ordered sulfurized nanofiber membrane.

[0033] Preferably, the polymer comprises at least one of polyacrylonitrile, polymethyl methacrylate, polystyrene and polyvinyl pyrrolidone; the ratio of the solute to the solvent is 0.8-1.2 g:10 mL; the electrospinning parameters are: voltage 18-24 kV, flow rate 0.6-1 mL·h -1 , receiver distance 10 ~ 20cm, humidity controlled at ~ 40%, drum speed 2000 ~ 3000r·min -1 The sulfur source includes one of sulfur powder, selenium sulfide and thiourea; the mass ratio of the ordered nanofiber membrane to the sulfur source is 1:3 to 8; the heating rate of the sulfurization treatment is 2 to 5 ° C min -1 ; The temperature is 350-450°C and the time is 3-6h; the diameter of the ordered sulfurized nanofibers in the ordered sulfurized nanofiber membrane is 50-300nm.

[0034] Furthermore, the preparation steps of the electrolyte in situ polymerized in the ordered nanofiber framework include:

[0035] dissolving a monomer, an initiator, and a lithium salt in an organic solvent to obtain an electrolyte precursor;

[0036] The electrolyte precursor is polymerized in situ to obtain an electrolyte polymerized in situ within the ordered nanofiber skeleton.

[0037] Preferably, the monomer is selected from at least one of polybutyl acrylate, polyethylene glycol diacrylate, pentaerythritol tetraacrylate and ethylene glycol diacrylate; the initiator is azobisisobutyronitrile; the lithium salt is at least one of lithium bis(fluorosulfonyl)imide (LiFSI), lithium trifluoromethanesulfonylimide (LiTFSI), lithium hexafluorophosphate (LiPF6) and lithium tetrafluoroborate (LiBF4); the organic solvent is selected from at least one of dimethyldimethoxysilane (DMDMS), ethylene glycol dimethyl ether (Glyme), dimethyl sulfoxide (DMSO) and dimethyldiethoxysilane (DMDES); the concentration of the lithium salt in the electrolyte precursor is 0.5-3M, the mass fraction of the monomer is 2.5%, and the mass fraction of the initiator is 0.15%; the temperature of the in situ polymerization is 60°C and the time is 12h.

[0038] This invention establishes continuous, uniform, and rapid lithium-ion transport throughout the battery by designing a fully ordered nanofiber battery assembly. This design effectively improves lithium-ion extraction / insertion kinetics, ensures uniform distribution of lithium-ion concentration and electric field, promotes uniform reactions at the anode and cathode, and thus achieves uniform deposition and stripping of metallic lithium. It also maximizes cathode material utilization, significantly improving the battery's cycle life and laying the foundation for the potential commercial application of lithium-sulfur batteries.

[0039] The present invention discloses the following technical effects:

[0040] The invention adopts electrostatic spinning to prepare the ordered porous carbon hollow tubes modified with lithium ions, ordered nanofibers, and ordered sulfurized nanofibers, which has the advantages of being simple, efficient, easy to operate, and low in cost.

[0041] The lithiophilic-modified ordered porous carbon hollow tubes prepared by the present invention serve as carriers for metallic lithium. They possess directional electron transport channels and uniform nucleation sites, promoting uniform deposition of metallic lithium, inhibiting lithium dendrite growth, and adapting to volume changes of the negative electrode during charge and discharge cycles. The in-situ polymerized electrolyte within the ordered nanofiber framework provides directional and uniform transport pathways, while the ordered sulfurized nanofibers exhibit uniform sulfur distribution. Furthermore, the lithium metal-sulfur battery prepared from these materials possesses a fully ordered structure that provides continuous and rapid lithium ion transport pathways throughout the battery, promoting uniform distribution of lithium ion flux, alleviating concentration polarization, and facilitating homogeneous reactions, thereby promoting uniform deposition and stripping of lithium metal and improving the utilization rate of the active material.

[0042] The fully ordered nanofiber structure that undergoes homogeneous reaction provided in the present invention is applied to quasi-solid-state lithium metal (lithium metal-sulfur battery), and the battery exhibits the characteristics of high specific capacity and excellent cycle stability, indicating that the fully ordered nanofiber structure provided by the present invention has important application prospects in the field of high-performance quasi-solid-state lithium metal batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings:

[0044] Figure 1 1 is the SEM image of the ordered porous carbon hollow tube modified by Zn-N / O and Co-N in Example 1;

[0045] Figure 2 Mapping diagram of the ordered porous carbon hollow tubes modified by Zn-N / O and Co-N in Example 1;

[0046] Figure 3 This is a SEM image of the electrolyte precursor after in-situ polymerization in Application Example 1;

[0047] Figure 4 This is the mapping diagram of the ordered sulfurized nanofiber membrane in Application Example 1;

[0048] Figure 5 This is the electrochemical performance diagram of the quasi-solid-state lithium metal full battery in Application Example 1;

[0049] Figure 6 The electrochemical performance of a quasi-solid-state lithium metal symmetrical battery assembled with the composite electrodes as positive and negative electrodes in Example 1 and Comparative Example 1;

[0050] Figure 7 is the SEM image of the disordered porous carbon hollow tube modified by Zn-N / O and Co-N in Comparative Example 1;

[0051] Figure 8 Mapping diagram of the disordered porous carbon hollow tubes modified by Zn-N / O and Co-N in Comparative Example 1;

[0052] Figure 9 This is a charge and discharge performance test diagram of the quasi-solid-state lithium metal full battery at a 0.1C rate for Application Example 1 and Comparative Application Example 1. DETAILED DESCRIPTION

[0053] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0054] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0055] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0056] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be illustrative only.

[0057] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0058] Unless otherwise specified, the room temperature in the specific embodiments of the present invention refers to 20-30°C.

[0059] Example 1

[0060] The preparation steps of the ordered porous carbon hollow tube-based lithium metal composite electrode are as follows:

[0061] S1. Dissolve 500 mg of PAN in 5 mL of DMF to obtain a uniform solution A; then add 945 mg of Zn(CH3COO)2 and 55 mg of Co(CH3COO)2 to 5 mL of DMF and stir evenly to obtain a solution B; solution A and solution B are evenly mixed to obtain an electrospinning precursor solution;

[0062] S2. Transfer the electrospinning precursor solution into a 10 mL syringe and inject it at 0.4 mL h under 18 kV high voltage. -1 The electrospinning was performed at a flow rate of 100 nm, the distance between the needle (24 G) and the collector was set to 15 cm, the humidity during electrospinning was controlled at 40%, and the rotating drum collector was set to 3000 r·min -1 , and then the electrospun product was placed in an oven at 60 ° C and dried for 12 h to obtain an ordered nanofiber membrane containing metal salts;

[0063] S3, the ordered nanofiber membrane containing 30 mg of metal salt was added to 20 mL of anhydrous ethanol solution of 2-methylimidazole (concentration of 0.04 wt%), and then kept at room temperature for 12 h to grow a BMZIF layer on the ordered nanofibers. The ordered nanofiber membrane with the BMZIF layer was washed three times with anhydrous ethanol, and then transferred to a vacuum drying oven at 70 ° C for 3 h to remove the anhydrous ethanol. It was then placed in a tube furnace and dried at 2 ° C·min under a nitrogen atmosphere. -1 The temperature was raised to 350℃ and calcined for 2h, followed by heating at 2℃·min -1 The temperature was raised to 700℃ and calcined for 3h to obtain ordered porous carbon hollow tubes modified with Zn-N / O and Co-N.

[0064] S4. Using high-purity argon protection, the metallic lithium was melted (230°C) in a glove box, and the ordered porous carbon hollow tube carrier modified with Zn-N / O and Co-N was contacted with the molten metallic lithium (10s). The molten metallic lithium spontaneously infiltrated into the pores of the hollow tube. After cooling, an ordered porous carbon hollow tube-based lithium metal composite electrode (ordered porous carbon hollow tube-based lithium metal composite electrode modified with Zn-N / O and Co-N) was obtained.

[0065] Application Example 1

[0066] Preparation of lithium metal-sulfur batteries (quasi-solid-state lithium metal full batteries):

[0067] S1. Dissolve 1 g of PAN in 10 mL of DMF and stir for 12 h to form a uniform precursor solution. Transfer the precursor solution into a syringe and inject at 20 kV at a speed of 0.8 mL h. -1Electrospinning was performed at a flow rate of 3000 r·min (receiving distance: 15 cm; needle specification: 24G; humidity ~40%). -1 The electrospun membrane obtained at a rotation speed was dried at 80 °C overnight to obtain an ordered nanofiber membrane;

[0068] S2. The ordered nanofiber membrane prepared in step S1 was placed on sulfur powder at a mass ratio of 1:4, and calcined at 450 °C for 3 h in a tubular furnace filled with nitrogen atmosphere at a heating rate of 2 °C min -1 , forming an ordered sulfurized nanofiber membrane;

[0069] S3. PETEA (pentaerythritol tetraacrylate) monomer, AIBN (azobisisobutyronitrile) initiator, and LiFSI are dissolved in DMMS to prepare an electrolyte precursor; in the electrolyte precursor, the concentration of LiFSI is 1.5 M, the concentration of PETEA is 2.5 wt %, and the concentration of AIBN is 0.15 wt %;

[0070] S4. Assemble a quasi-solid-state lithium metal full battery: use the ordered porous carbon hollow tube-based lithium metal composite electrode prepared in Example 1 as the working electrode (negative electrode), the ordered nanofiber membrane in step S1 as the diaphragm, the ordered sulfide nanofiber membrane in step S2 as the counter electrode (positive electrode), and the electrolyte precursor in step S3 as the electrolyte (60 μL) to assemble a 2025 button battery, which is then placed in an oven at 60°C for 12 hours for in situ polymerization of the electrolyte precursor to obtain a quasi-solid-state lithium metal full battery.

[0071] Example 2

[0072] The preparation steps of the ordered porous carbon hollow tube-based lithium metal composite electrode are as follows:

[0073] S1. Dissolve 500 mg of PAN in 5 mL of DMF to obtain a uniform solution A; then add 1005 mg of Zn(CH3COO)2 and 95 mg of Ni(CH3COO)2 to 5 mL of DMF and stir evenly to obtain a solution B; solution A and solution B are evenly mixed to obtain an electrospinning precursor solution;

[0074] S2. Transfer the electrospinning precursor solution into a 10 mL syringe and inject it at 0.4 mL h under 18 kV high voltage. -1 The electrospinning was performed at a flow rate of 100 nm, the distance between the needle (24 G) and the collector was set to 15 cm, the humidity during electrospinning was controlled at 40%, and the rotating drum collector was set to 3000 r·min -1 , and then the electrospun product was placed in an oven at 60 ° C and dried for 12 h to obtain an ordered nanofiber membrane containing metal salts;

[0075] S3, the ordered nanofiber membrane containing 50 mg of metal salt was added to 20 mL of anhydrous ethanol solution of 2-methylimidazole (concentration of 0.06 wt%), and then kept at room temperature for 12 h to grow a BMZIF layer on the ordered nanofibers. The ordered nanofiber membrane with the BMZIF layer was washed three times with anhydrous ethanol, and then transferred to a vacuum drying oven at 70 ° C for 3 h to remove the anhydrous ethanol. It was then placed in a tube furnace and dried at 2 ° C·min under a nitrogen atmosphere. -1 The temperature was raised to 350℃ and calcined for 2h, followed by heating at 2℃·min -1 The temperature was raised to 700℃ and calcined for 3h to obtain Zn-N / O and Ni-N modified ordered porous carbon hollow tubes.

[0076] S4. Using high-purity argon protection, the metallic lithium was melted (230°C) in a glove box, and the ordered porous carbon hollow tube carrier modified with Zn-N / O and Ni-N was contacted with the molten metallic lithium (8s). The molten metallic lithium spontaneously infiltrated into the pores of the hollow tube. After cooling, an ordered porous carbon hollow tube-based lithium metal composite electrode (ordered porous carbon hollow tube-based lithium metal composite electrode modified with Zn-N / O and Ni-N) was obtained.

[0077] Application Example 2

[0078] Preparation of lithium metal-sulfur batteries (quasi-solid-state lithium metal full batteries):

[0079] S1. Dissolve 1 g of PAN in 10 mL of DMF and stir for 12 h to form a uniform precursor solution. Transfer the precursor solution into a syringe and inject at 20 kV at a speed of 0.8 mL h. -1 Electrospinning was performed at a flow rate of 3000 r·min (receiving distance: 15 cm; needle specification: 24G; humidity ~40%). -1 The electrospun membrane obtained at a rotation speed was dried at 80 °C overnight to obtain an ordered nanofiber membrane;

[0080] S2. The ordered nanofiber membrane prepared in step S1 was placed on sulfur powder at a mass ratio of 1:4, and calcined at 450 °C for 3 h in a tubular furnace filled with nitrogen atmosphere at a heating rate of 2 °C min -1 , forming an ordered sulfurized nanofiber membrane;

[0081] S3. PETEA (pentaerythritol tetraacrylate) monomer, AIBN (azobisisobutyronitrile) initiator, and LiFSI are dissolved in DMMS to prepare an electrolyte precursor; in the electrolyte precursor, the concentration of LiFSI is 2M, the concentration of PETEA is 2.5wt%, and the concentration of AIBN is 0.15wt%;

[0082] S4. Assemble a quasi-solid-state lithium metal full battery: use the ordered porous carbon hollow tube-based lithium metal composite electrode prepared in Example 1 as the working electrode (negative electrode), the ordered nanofiber membrane in step S1 as the diaphragm, the ordered sulfide nanofiber membrane in step S2 as the counter electrode (positive electrode), and the electrolyte precursor in step S3 as the electrolyte (60 μL) to assemble a 2025 button battery, which is then placed in an oven at 60°C for 12 hours for in situ polymerization of the electrolyte precursor to obtain a quasi-solid-state lithium metal full battery.

[0083] Example 3

[0084] The preparation steps of the ordered porous carbon hollow tube-based lithium metal composite electrode are as follows:

[0085] S1. Dissolve 500 mg of PAN in 5 mL of DMF to obtain a uniform solution A; then add 745 mg of Zn(CH3COO)2 and 255 mg of CH3COOAg to 5 mL of DMF and stir evenly to obtain a solution B; solution A and solution B are evenly mixed to obtain an electrospinning precursor solution;

[0086] S2. Transfer the electrospinning precursor solution into a 10 mL syringe and inject it at 0.4 mL h under 18 kV high voltage. -1 The electrospinning was performed at a flow rate of 100 nm, the distance between the needle (24 G) and the collector was set to 15 cm, the humidity during electrospinning was controlled at 40%, and the rotating drum collector was set to 3000 r·min -1 , and then the electrospun product was placed in an oven at 60 ° C and dried for 12 h to obtain an ordered nanofiber membrane containing metal salts;

[0087] S3. The ordered nanofiber membrane containing 100 mg of metal salt was added to 20 mL of anhydrous ethanol solution of 2-methylimidazole (concentration of 0.08 wt%), and then kept at room temperature for 12 h to grow a ZIF layer on the ordered nanofibers. The ordered nanofiber membrane with the ZIF layer was washed three times with anhydrous ethanol, and then transferred to a vacuum drying oven at 70 ° C for 3 h to remove the anhydrous ethanol. It was then placed in a tube furnace and dried at 2 ° C·min under a nitrogen atmosphere. -1 The temperature was raised to 350℃ and calcined for 2h, followed by heating at 2℃·min -1 The temperature was raised to 700℃ and calcined for 3h to obtain ordered porous carbon hollow tubes modified with Zn-N / O and Ag-N.

[0088] S4. Using high-purity argon protection, the metallic lithium was melted (230°C) in a glove box, and the ordered porous carbon hollow tube carrier modified with Zn-N / O and Ag-N was contacted with the molten metallic lithium (6s). The molten metallic lithium spontaneously infiltrated into the pores of the hollow tube. After cooling, an ordered porous carbon hollow tube-based lithium metal composite electrode (ordered porous carbon hollow tube-based lithium metal composite electrode modified with Zn-N / O and Ag-N) was obtained.

[0089] Application Example 3

[0090] Preparation of lithium metal-sulfur batteries (quasi-solid-state lithium metal full batteries):

[0091] S1. Dissolve 1 g of PAN in 10 mL of DMF and stir for 12 h to form a uniform precursor solution. Transfer the precursor solution into a syringe and inject at 20 kV at a speed of 0.8 mL h. -1 Electrospinning was performed at a flow rate of 3000 r·min (receiving distance: 15 cm; needle specification: 24G; humidity ~40%). -1 The electrospun membrane obtained at a rotation speed was dried at 80 °C overnight to obtain an ordered nanofiber membrane;

[0092] S2. The ordered nanofiber membrane prepared in step S1 was placed on sulfur powder at a mass ratio of 1:4, and calcined at 450 °C for 3 h in a tubular furnace filled with nitrogen atmosphere at a heating rate of 2 °C min -1 , forming an ordered sulfurized nanofiber membrane;

[0093] S3. PETEA (pentaerythritol tetraacrylate) monomer, AIBN (azobisisobutyronitrile) initiator, and LiFSI are dissolved in DMMS to prepare an electrolyte precursor; in the electrolyte precursor, the concentration of LiFSI is 3M, the concentration of PETEA is 2.5wt%, and the concentration of AIBN is 0.15wt%;

[0094] S4. Assemble a quasi-solid-state lithium metal full battery: use the ordered porous carbon hollow tube-based lithium metal composite electrode prepared in Example 1 as the working electrode (negative electrode), the ordered nanofiber membrane in step S1 as the diaphragm, the ordered sulfide nanofiber membrane in step S2 as the counter electrode (positive electrode), and the electrolyte precursor in step S3 as the electrolyte (60 μL) to assemble a 2025 button battery, which is then placed in an oven at 60°C for 12 hours for in situ polymerization of the electrolyte precursor to obtain a quasi-solid-state lithium metal full battery.

[0095] Example 4

[0096] Compared with Example 1, the only difference is that "2℃·min -1 The rate of heating to 700℃ and calcining for 3h was adjusted to 2℃·min -1The temperature was raised to 900℃ and calcined for 3h.

[0097] Application Example 4

[0098] Preparation of lithium metal-sulfur batteries (quasi-solid-state lithium metal full batteries):

[0099] Same as Application Example 1.

[0100] Example 5

[0101] Compared with Example 1, the only difference is that "2℃·min -1 The rate of heating to 700℃ and calcining for 3h was adjusted to 2℃·min -1 The temperature was raised to 1100°C and calcined for 3 hours.

[0102] Application Example 5

[0103] Preparation of lithium metal-sulfur batteries (quasi-solid-state lithium metal full batteries):

[0104] Same as Application Example 1.

[0105] Comparative Example 1

[0106] The preparation steps of disordered porous carbon hollow tube-based lithium metal composite electrode are as follows:

[0107] S1. Dissolve 500 mg of PAN in 5 mL of DMF to obtain a uniform solution A; then add 945 mg of Zn(CH3COO)2 and 55 mg of Co(CH3COO)2 to 5 mL of DMF and stir evenly to obtain a solution B; solution A and solution B are evenly mixed to obtain an electrospinning precursor solution;

[0108] S2, transfer the electrospinning precursor solution into a 10mL syringe and inject it at 0.4mLh under 18kV high voltage. -1 The electrospinning was performed at a flow rate of 100 nm, the distance between the needle (24 G) and the collector was set to 15 cm, the humidity during electrospinning was controlled at 40%, and the rotating drum collector was set to 300 r·min -1 , and then the electrospun product was placed in an oven at 60 ° C and dried for 12 h to obtain a disordered nanofiber membrane containing metal salts;

[0109] S3. A disordered nanofiber membrane containing 30 mg of metal salt was added to 20 mL of anhydrous ethanol solution of 2-methylimidazole (concentration of 0.04 wt%), and then kept at room temperature for 12 h to grow a BMZIF layer on the disordered nanofibers. The disordered nanofiber membrane with the BMZIF layer was washed three times with anhydrous ethanol, and then transferred to a vacuum drying oven at 70 ° C for 3 h to remove the anhydrous ethanol. It was then placed in a tube furnace and dried at 2 ° C·min under a nitrogen atmosphere.-1 The temperature was raised to 350℃ and calcined for 2h, followed by heating at 2℃·min -1 The temperature was raised to 700℃ and calcined for 3h to obtain Zn-N / O and Co-N modified disordered porous carbon hollow tubes.

[0110] S4. Using high-purity argon protection, the metallic lithium was melted (230°C) in a glove box, and the Zn-N / O and Co-N modified disordered porous carbon hollow tube support was brought into contact with the molten metallic lithium (16s). The molten metallic lithium spontaneously infiltrated into the pores of the hollow tube, and after cooling, a disordered porous carbon hollow tube-based lithium metal composite electrode (Zn-N / O and Co-N modified disordered porous carbon hollow tube-based lithium metal composite electrode) was obtained.

[0111] Comparative Application Example 1

[0112] Preparation of lithium metal-sulfur batteries (quasi-solid-state lithium metal full batteries):

[0113] S1. Dissolve 1 g of PAN in 10 mL of DMF and stir for 12 h to form a uniform precursor solution. Transfer the precursor solution into a syringe and inject at 20 kV at a speed of 0.8 mL h. -1 Electrospinning was performed at a flow rate of 300 r·min (receiving distance: 15 cm; needle specification: 24G; humidity ~40%). -1 The electrospun membrane obtained at a rotation speed was dried at 80 °C overnight to obtain a disordered nanofiber membrane;

[0114] S2. The disordered nanofiber membrane prepared in step S1 was placed on sulfur powder at a mass ratio of 1:4, and calcined at 450 °C for 3 h in a tubular furnace filled with nitrogen atmosphere at a heating rate of 2 °C min -1 , forming a disordered sulfurized nanofiber membrane;

[0115] S3. PETEA (pentaerythritol tetraacrylate) monomer, AIBN (azobisisobutyronitrile) initiator, and LiFSI are dissolved in DMMS to prepare an electrolyte precursor; in the electrolyte precursor, the concentration of LiFSI is 1.5 M, the concentration of PETEA is 2.5 wt %, and the concentration of AIBN is 0.15 wt %;

[0116] S4. Assemble a quasi-solid-state lithium metal full battery: use the disordered porous carbon hollow tube-based lithium metal composite electrode prepared in Comparative Example 1 as the working electrode (negative electrode), the disordered nanofiber membrane in step S1 as the diaphragm, the disordered sulfide nanofiber membrane in step S2 as the counter electrode (positive electrode), and the electrolyte precursor in step S3 as the electrolyte (60 μL) to assemble a 2025 button battery, which is then placed in an oven at 60°C for 12 hours for in-situ polymerization of the electrolyte precursor to obtain a quasi-solid-state lithium metal full battery.

[0117] Test example

[0118] Figure 1 This is the SEM image of the ordered porous carbon hollow tubes modified with Zn-N / O and Co-N in Example 1. It can be seen from the figure that the porous carbon hollow tubes show an orderly arrangement trend and the diameter is about 300 nm.

[0119] Figure 2 This is the mapping diagram of the ordered porous carbon hollow tubes modified with Zn-N / O and Co-N in Example 1. It can be seen from the figure that zinc and cobalt are evenly distributed on the ordered porous carbon hollow tubes.

[0120] Figure 3 This is a SEM image of the electrolyte precursor after in-situ polymerization in Application Example 1. It can be seen from the figure that the surface of the electrolyte membrane after in-situ polymerization with ordered polyacrylonitrile nanofibers as the skeleton is smooth.

[0121] Figure 4 This is the mapping diagram of the ordered sulfurized nanofiber membrane in Application Example 1. It can be seen from the figure that the fibers are arranged in an orderly manner and the sulfur is evenly distributed on the nanofibers.

[0122] The electrochemical performance of the quasi-solid-state lithium metal full battery obtained in Application Example 1 was tested at room temperature. The results are as follows Figure 5 shown.

[0123] Figure 5 This is the electrochemical performance diagram of the quasi-solid-state lithium metal full battery in Application Example 1. It can be seen from the figure that when the ordered porous carbon hollow tube-based lithium metal composite electrode modified with Zn-N / O and Co-N is used as the negative electrode, the electrolyte is in situ polymerized in the ordered polyacrylonitrile nanofiber skeleton, and the ordered sulfurized polyacrylonitrile nanofiber positive electrode is assembled into a lithium-sulfur full battery. When the charge and discharge performance test is carried out at a 1C rate, the capacity can reach 1096 mAh g -1 This fully ordered nanofiber structure with homogeneous reaction significantly promotes the uniform deposition of lithium metal and glass stripping, and improves the utilization rate of active materials.

[0124] The composite electrodes prepared in Example 1 and Comparative Example 1 were used as positive and negative electrodes to assemble a quasi-solid-state lithium metal symmetrical battery. The electrochemical performance test results are shown in FIG. Figure 6 shown.

[0125] Figure 6 The electrochemical performance of the quasi-solid-state lithium metal symmetrical battery assembled with the composite electrodes as positive and negative electrodes in Example 1 and Comparative Example 1 can be seen from the figure. When tested at 25°C, the symmetrical battery assembled with the ordered porous carbon hollow tube-based lithium metal composite electrode of Example 1 has a current density of 0.5 mA cm -2 0.5 mAh cm-1 was deposited and stripped -2Metallic lithium has a smaller polarization voltage and an ultra-long cycle life.

[0126] Figure 7 This is the SEM image of the disordered porous carbon hollow tube modified by Zn-N / O and Co-N in Comparative Example 1. It can be seen from the figure that the disordered nanofibers are randomly arranged and have a tubular structure with a diameter of about 350 nm.

[0127] Figure 8 This is the mapping diagram of the disordered porous carbon hollow tube modified by Zn-N / O and Co-N in Comparative Example 1. It can be seen from the figure that zinc and cobalt are distributed on the porous carbon hollow tube, but due to the random arrangement of the fibers, the distribution is uneven.

[0128] Figure 9 The figures are the charge and discharge performance test diagrams of the quasi-solid-state lithium metal full battery of Application Example 1 and Comparative Application Example 1 at a rate of 0.1C. It can be seen from the figure that the full-ordered nanofiber structure full battery with homogeneous reaction has a higher capacity and longer cycle performance at 0.1C. This is attributed to the continuous and rapid lithium ion transmission path provided by the fully ordered nanofiber structure, which is conducive to the uniform distribution of lithium ion flux, reduces concentration polarization, promotes uniform lithium metal deposition / stripping, and improves the utilization rate of active materials.

[0129] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0130] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A lithium metal-sulfur battery comprising: A positive electrode, a negative electrode and an electrolyte, characterized in that the positive electrode is an ordered sulfurized nanofiber membrane; the negative electrode is an ordered porous carbon hollow tube-based lithium metal composite electrode; the electrolyte is an electrolyte in situ polymerized within an ordered nanofiber skeleton; The preparation steps of the ordered sulfurized nanofiber membrane include: using a polymer as a solute and N,N-dimethylformamide as a solvent to obtain an ordered nanofiber membrane by electrospinning; mixing the ordered nanofiber membrane with a sulfur source, and performing a sulfurization treatment to obtain the ordered sulfurized nanofiber membrane; The electrospinning parameters in the preparation step of the ordered sulfurized nanofiber membrane are: voltage 18-24 kV, flow rate 0.6-1 mL·h −1 , receiver distance 10~20cm, humidity controlled at 40%, drum speed 2000~3000r·min −1 ; The preparation steps of the electrolyte in situ polymerized in the ordered nanofiber framework include: dissolving a monomer, an initiator and a lithium salt in an organic solvent to obtain an electrolyte precursor; in situ polymerizing the electrolyte precursor to obtain the electrolyte in situ polymerized in the ordered nanofiber framework; The preparation steps of the ordered porous carbon hollow tube-based lithium metal composite electrode include: dissolving a carbon-forming polymer and a metal salt in N,N-dimethylformamide to obtain a precursor solution; electrospinning the precursor solution to obtain an ordered nanofiber membrane containing the metal salt; in situ growing a metal organic framework layer on the ordered nanofiber membrane containing the metal salt, followed by carbonization etching to obtain a lithium-philic modified ordered porous carbon hollow tube; contacting the lithium-philic modified ordered porous carbon hollow tube with molten metal lithium, and obtaining the ordered porous carbon hollow tube-based lithium metal composite electrode after infiltration; The electrospinning parameters in the preparation step of the ordered porous carbon hollow tube-based lithium metal composite electrode are: voltage 15-22 kV, flow rate 0.3-0.6 mL·h −1 , receiver distance 10~20cm, humidity controlled at 40%, drum speed 2000~3000r·min −1 .

2. The lithium metal-sulfur battery according to claim 1, wherein In the preparation steps of the ordered sulfurized nanofiber membrane: The polymer comprises at least one of polyacrylonitrile, polymethyl methacrylate, polystyrene and polyvinyl pyrrolidone; and / or The solute and solvent are used in a ratio of 0.8 to 1.2 g:10 mL; and / or The sulfur source comprises one of sulfur powder, selenium sulfide and thiourea; and / or The mass ratio of the ordered nanofiber membrane to the sulfur source is 1:3-8; and / or The heating rate of the vulcanization treatment is 2-5°C·min −1 , temperature is 350~450℃, time is 3~6h.

3. The lithium metal-sulfur battery according to claim 1, wherein In the preparation step of the electrolyte in situ polymerized in the ordered nanofiber framework: The monomer is selected from at least one of polyethylene glycol diacrylate, pentaerythritol tetraacrylate and ethylene glycol diacrylate; and / or The initiator is azobisisobutyronitrile; and / or The lithium salt is at least one of lithium bis(fluorosulfonyl)imide, lithium trifluoromethanesulfonylimide, lithium hexafluorophosphate and lithium tetrafluoroborate; and / or The organic solvent is selected from at least one of dimethyldimethoxysilane, ethylene glycol dimethyl ether, dimethyl sulfoxide and dimethyldiethoxysilane; and / or The concentration of lithium salt in the electrolyte precursor is 0.5-3M, the mass fraction of the monomer is 2.5%, and the mass fraction of the initiator is 0.15%; and / or The in-situ polymerization was carried out at a temperature of 60° C. and for 12 hours.

4. The lithium metal-sulfur battery according to claim 1, wherein The steps for preparing the ordered porous carbon hollow tube-based lithium metal composite electrode are: The carbon-forming polymer comprises at least one of polyacrylonitrile, polymethyl methacrylate, polystyrene and polyvinyl pyrrolidone; and / or The metal salt comprises at least one of zinc acetate, cobalt acetate, silver acetate, nickel acetate and copper acetate; and / or The concentration of the carbon-forming polymer in the precursor solution is 8-12 wt %, and the concentration of the metal salt is 2-5 wt %; and / or The carbonization etching is carried out in a nitrogen atmosphere, at a temperature of 700-1100°C, for 2-6 hours, and at a heating rate of 2-5°C·min −1 ; and / or The step of in-situ growing a metal organic framework layer comprises: placing the ordered nanofiber membrane containing metal salt in a 2-methylimidazole solution to in-situ grow a metal organic framework on the surface of the fiber membrane.

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