CN114975888A - Preparation method for preparing tin or tin dioxide @ hollow porous carbon nanofiber flexible electrode by regulating and controlling carbonization temperature - Google Patents

Preparation method for preparing tin or tin dioxide @ hollow porous carbon nanofiber flexible electrode by regulating and controlling carbonization temperature Download PDF

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CN114975888A
CN114975888A CN202210750445.6A CN202210750445A CN114975888A CN 114975888 A CN114975888 A CN 114975888A CN 202210750445 A CN202210750445 A CN 202210750445A CN 114975888 A CN114975888 A CN 114975888A
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hpcnfs
tin
flexible electrode
sno
carbon nanofiber
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葛明政
张伟
梁芳华
曹春艳
张海峰
张瑜
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Nantong University
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
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    • H—ELECTRICITY
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    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1393—Processes of manufacture of electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/364—Composites as mixtures
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/387—Tin or alloys based on tin
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
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    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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    • Y02E60/10—Energy storage using batteries

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Abstract

The invention provides a preparation method for preparing a tin or tin dioxide @ hollow porous carbon nanofiber flexible electrode by regulating and controlling a carbonization temperature, and belongs to the technical field of materials. The technical scheme is as follows: the method comprises the following steps: (1) preparing a core-shell spinning solution; (2) SnO 2 Manufacturing method of @ HPCNFs and Sn @ HPCNFs flexible electrodePreparing; (3) SnO 2 And testing the electrochemical performance of the @ HPCNFs and Sn @ HPCNFs flexible electrode. The invention has the beneficial effects that: the invention adopts the coaxial electrostatic spinning combined carbonization process to prepare the hollow porous carbon nanofiber flexible electrode which can be directly used as a flexible self-supporting film, the nitrogen-doped carbon nanofiber three-dimensional network provides a continuous electron transmission channel, and the one-dimensional hollow structure effectively relieves Sn or SnO 2 The volume expansion changes in the charging and discharging process to form a stable SEI layer, and meanwhile, the surface porous structure reduces the diffusion energy barrier of lithium ions and improves the diffusion rate.

Description

Preparation method for preparing tin or tin dioxide @ hollow porous carbon nanofiber flexible electrode by regulating and controlling carbonization temperature
Technical Field
The invention relates to the technical field of materials, in particular to a preparation method for preparing a tin or tin dioxide @ hollow porous carbon nanofiber flexible electrode by regulating and controlling a carbonization temperature.
Background
The development of high power density and energy density lithium ion batteries has become a necessary condition to meet the increasing energy consumption of electric vehicles, hybrid electric vehicles, and portable electronic devices. Therefore, a new electrode material having large energy storage and ultra-fast charging capability is developed. From a material perspective, tin-based electrode materials (Sn and SnO) 2 994 and 1494mAh/g theoretical capacities, respectively) because of their high mass and volumetric capacity, avoid solvent intercalation, improve the safety performance of lithium ion batteries, and, in addition, have low potential hysteresis, these advantages have led to the widespread study of tin-based materials as active materials for lithium storage, being considered as one of the most promising candidate materials to replace commercial graphite cathodes (372 mAh/g). Nevertheless, the large volume expansion of the high capacity tin-based material during lithium ion intercalation/deintercalation deteriorates the structural stability thereof and results in the continuous growth of Solid Electrolyte Interface (SEI), hinders the diffusion of lithium ions, causes irreversible capacity loss of metallic tin, and results in poor rate capability and cycle performance.
Therefore, many researchers have conducted extensive research to solve the problems occurring with tin-based electrode materials, and nanostructure strategies and composition adjustment strategies have now been proposed to accommodate volume expansion and promote reaction kinetics. Although it is not limited toTin-based nanomaterials (i.e., nanoparticles, nanotubes, nanowires, etc.) exhibit some strain relaxation to volume changes, shortening the lithium ion diffusion path, but are still affected by inherent fragility and SEI sustained growth due to their large specific surface area. In this connection, core-shell structures and various Sn/C and SnO appear 2 the/C, etc. structure, since Sn or SnO2 thereof is confined in the carbon nanotubes, nanofibers and graphene layers, allows the nanocomposite material to accommodate huge volume changes and facilitates the formation of stable SEI. However, the external carbon coating, nanotubes, nanofibers and graphene limit lithium ion diffusion, inhibiting the improvement of its electrochemical performance. Thus, intercalation of nanostructured tin-based electrode materials into a porous matrix is a potential strategy to enhance lithium ion diffusion kinetics.
Disclosure of Invention
The invention aims to provide a preparation method for preparing a tin or tin dioxide @ hollow porous carbon nanofiber flexible electrode by regulating and controlling the carbonization temperature, the process is simple and convenient and easy to operate, the spinning is carried out by a coaxial electrostatic spinning process, a thermoplastic high polymer material is removed by a carbonization process to form a hollow porous fiber, and SnO is generated by oxidation or reduction in the inner wall of a cavity in the fiber 2 Or Sn with a porous structure of Li + Convenient access is provided for the inlet and outlet, and Li is shortened + The diffusion path reduces the energy barrier of lithium ion and electron transfer, and simultaneously, the N atoms in the carbon layer improve the conductivity of the material; meanwhile, the one-dimensional hollow porous structure can effectively relieve the stress change caused by volume expansion of the tin-based material in the charging and discharging process, a stable SEI layer is formed, and SnO is solved through the unique structural design 2 Or the problems of large volume change, unstable SEI film, poor conductivity and the like of Sn in the charge-discharge process, and simultaneously the SnO is researched by regulating and controlling the carbonization temperature 2 And Sn, so that SnO synthesized at a low carbonization temperature of less than 500 DEG C 2 The @ HPCNFs flexible electrode has high capacity under low current density, and in addition, the Sn @ HPCNFs flexible electrode synthesized at the high carbonization temperature of more than 500 ℃ shows high capacity under high current density, has rapid charge and discharge performance, and is expected to construct a flexible electrode with high energy density and rapid charge and dischargeAn electrode material of electrical properties.
In order to achieve the purpose, the invention adopts the following technical scheme: a preparation method for preparing a tin or tin dioxide @ hollow porous carbon nanofiber flexible electrode by regulating and controlling a carbonization temperature comprises the following specific contents:
respectively filling the core-shell spinning solution into an injector, performing electrostatic spinning through a coaxial electrostatic spinning device to obtain electrostatic spinning fibers, performing pre-oxidation treatment on the electrostatic spinning fibers in the air atmosphere, and then performing carbonization treatment on the pre-oxidized electrostatic spinning fibers at different temperatures to finally obtain SnO 2 @ HPCNFs and Sn @ HPCNFs flexible electrodes.
Further, the temperature is 15-30 ℃ and the humidity is 20-50%.
Furthermore, the capacity of the syringe is 5-100mL, the diameter of the inner needle of the coaxial metal needle is 0.3-0.9mm, and the diameter of the outer needle is 0.9-2.8 mm.
Further, the voltage is set to be 10-20kV, the flow rate of the core spinning solution is 0.1-0.2mL/min, the flow rate of the shell spinning solution is 0.1-0.5mL/min, the receiving distance is 10-20cm, and the spinning time is 1-24 h.
Further, the pre-oxidation temperature is 100-300 ℃, the temperature rise and reduction rate is 1-10 ℃/min, and the pre-oxidation time is 1-5 h.
Further, the high-temperature carbonization temperature is 400-.
Further, the thermoplastic polymer material is dispersed in the DMF solution, and heated and stirred continuously for a period of time until the particles are completely dissolved.
Furthermore, the thermoplastic polymer material is one or a combination of PMMA, PS and the like, and the weight ratio of the thermoplastic polymer material to the DMF solution is 1: 1-20.
Further, the preparation method is characterized in that the heating temperature is 20-100 ℃ during stirring in the first step, the heating time is 1-10h, and the stirring speed is 10-1500 rpm.
Further, the tin source precursor and the PAN powder are respectively added into the mixed solution, and after the mixture is heated and continuously stirred for a period of time, the mixture is completely dissolved.
Further, the tin source precursor is SnCl 2 ·2H 2 O、SnCl 2 ·5H 2 O、C 4 H 6 O 4 Sn、C 2 O 4 Sn and the like, and the weight ratio of the tin source precursor to the mixed solution is 1: 1-20.
Further, the weight ratio of the PAN powder to the mixed solution is 1: 1-15.
Further, the heating temperature is 20-100 ℃, the heating time is 2-20h, and the stirring speed is 10-1500 rpm.
In order to better realize the aim of the invention, the invention also provides a method for preparing the tin or tin dioxide @ hollow porous carbon nanofiber flexible electrode (SnO) by regulating and controlling the carbonization temperature 2 @ HPCNFs or Sn @ HPCNFs), specifically comprising the following steps:
(1) preparing a core-shell spinning solution: thermoplastic polymer material is dispersed in DMF solution and heated and stirred continuously for some time until the particles are dissolved completely to form mixed solution. And respectively adding the tin source precursor and the PAN powder into the mixed solution, heating and continuously stirring for a period of time until the tin source precursor and the PAN powder are completely dissolved to form the core-shell spinning solution.
(2)SnO 2 Preparing flexible electrodes of @ HPCNFs and Sn @ HPCNFs: and respectively filling the core-shell spinning solution into an injector, and performing electrostatic spinning through a coaxial electrostatic spinning device to obtain the electrostatic spinning fiber. And (3) carrying out pre-oxidation treatment on the electrostatic spinning fiber in an air atmosphere to stabilize the fiber structure. Then, the pre-oxidized electrostatic spinning fiber is treated at different carbonization temperatures to finally obtain SnO 2 @ HPCNFs and Sn @ HPCNFs flexible electrodes.
(3)SnO 2 Testing the electrochemical performance of the @ HPCNFs and Sn @ HPCNFs flexible electrode: the flexible electrode is directly used as a pole piece to assemble the lithium ion battery, the cycle performance and the rate performance of the battery are tested, and the electrochemical performance of the battery is obtained by performing cyclic voltammetry test, alternating current impedance test and constant current intermittent titration test.
Wherein the thermoplastic polymer material in the step (1) is one or a combination of more of PMMA, PS and the like, the weight ratio of the thermoplastic polymer material to the DMF solution is 1:1-20,
wherein the heating temperature in the step (1) is 20-100 ℃, the heating time is 1-10h, and the stirring speed is 10-1500 rpm.
Wherein, the precursor of the tin source in the step (1) is SnCl 2 ·2H 2 O、SnCl 2 ·5H 2 O、C 4 H 6 O 4 Sn、C 2 O 4 Sn, and the like, wherein the weight ratio of the tin source precursor to the mixed solution is 1: 1-20.
Wherein the weight ratio of the PAN powder to the mixed solution in the step (1) is 1: 1-15.
Wherein the heating temperature is 20-100 ℃ during stirring in the step (1), the heating time is 2-20h, and the stirring speed is 0-15000 rpm.
Wherein, in the electrostatic spinning process in the step (2), the capacity of an injector is 5-100mL, the diameter of an inner needle of the coaxial metal needle is 0.3-0.9mm, and the diameter of an outer needle is 0.9-2.8 mm.
Wherein in the electrostatic spinning process in the step (2), the voltage is set to be 10-20kV, the flow rate of the core spinning solution is 0.1-0.2mL/min, the flow rate of the shell spinning solution is 0.1-0.5mL/min, the receiving distance is 10-20cm, and the spinning time is 1-24 h.
Wherein, in the electrostatic spinning process in the step (2), the temperature is 15-30 ℃, and the humidity is 20-50%.
Wherein the pre-oxidation temperature in the step (2) is 100-300 ℃, the temperature rise and reduction rate is 1-10 ℃/min, and the pre-oxidation time is 1-5 h.
Wherein the high-temperature carbonization temperature in the step (2) is 400-.
Wherein, the diameter of the flexible electrode slice in the step (3) is 10mm, and the mass is 0.3-10 mg.
Wherein the temperature of the vacuum oven in the step (3) is 100 ℃, and the drying time is 10-24 h.
Wherein, the load mass of the pole piece in the step (3) is 0.4-10mg/cm 2 。
Wherein, the testing voltage range of the half cell in the step (3) is 0.01-4V, the charging and discharging current is 0.05-10A/g, and the cycle number is 100-6000 circles. The sweep rate of the cyclic voltammetry test is 0.1-100mV/s, and the voltage range is 0.01-4V.
Wherein, in the step (3), the frequency range of the EIS test is 0.01 to 10 6 Hz, and the voltage amplitude is 1-10 mV. The current density range of the GITT test is 0.1-10A/g, the voltage range is 0.01-4V, and the charging and discharging time is 10-120 min.
Compared with the prior art, the invention has the beneficial effects that:
(1) according to the invention, the coaxial electrostatic spinning technology is adopted to prepare the electrostatic spinning fiber, the carbonization process is combined to remove the thermoplastic high polymer material, so that the hollow porous carbon nanofiber flexible electrode is formed, the process is simple and convenient, the operation is easy, the controllability is good, the flexible self-supporting membrane can be directly used as a flexible self-supporting membrane, and the complicated steps of preparing a pole piece by using a traditional coating method are reduced.
(2) The one-dimensional channel structure formed by the N-doped hollow porous carbon nanofiber accelerates electron transfer, improves electron conductivity and inhibits SnO 2 And volume expansion of Sn, which helps to form a stable SEI layer; in addition, a large number of holes are formed in the surface of the fiber, so that an ion transmission channel is optimized, the energy barrier of ion transfer is reduced, and the rapid transfer of the ion is accelerated.
(3) The invention synthesizes tin source precursor into different substances (SnO) through oxidation reduction by controlling the carbonization temperature 2 And Sn), research SnO 2 And Sn, e.g. SnO synthesized with a low carburation temperature of less than 500 ℃ 2 The @ HPCNFs flexible electrode has high specific capacity under low current density, and the Sn @ HPCNFs flexible electrode synthesized at the high carbonization temperature of more than 500 ℃ has high capacity and excellent rapid charge and discharge performance under high current density.
Drawings
FIG. 1 is a SnO prepared according to example 1 of the present invention 2 A schematic diagram of a preparation method of @ HPCNFs and Sn @ HPCNFs flexible electrode.
FIG. 2 is an SEM image of electrospun fiber prepared in example 1 of the present invention.
FIG. 3 is a SnO prepared in example 1 of the present invention 2 SEM image of @ HPCNFs flexible electrode.
FIG. 4 is SnO prepared according to example 1 of the present invention 2 Low resolution TEM images (a), high resolution TEM images (b, c) of @ HPCNFs flexible electrodes.
FIG. 5 is SnO prepared according to example 1 of the present invention 2 The XRD patterns of @ HPCNFs, Sn @ HPCNFs flexible electrode prepared in example 2.
FIG. 6 is SnO prepared according to example 1 of the present invention 2 @ HPCNFs, XPS graph of Sn @ HPCNFs flexible electrode prepared in example 2.
FIG. 7 is SnO prepared according to example 1 of the present invention 2 @ HPCNFs, and high resolution XPS spectra of C1s (a) and Sn 3d (b) of the Sn @ HPCNFs flexible electrode prepared in example 2.
FIG. 8 is SnO prepared according to example 1 of the present invention 2 @ HPCNFs, Raman spectra of Sn @ HPCNFs flexible electrode prepared in example 2.
FIG. 9 is a SnO prepared in example 1 of the present invention 2 @ hpcnfs (a), Sn @ hpcnfs prepared in example 2, (b) CV plots of the flexible electrode at different scan rates.
FIG. 10 is a SnO prepared in example 1 of the present invention 2 @ HPCNFs, b value (a) of the Sn @ HPCNFs flexible electrode prepared in example 2, and a capacitance contribution area graph (b) at different scanning rates.
FIG. 11 is SnO prepared according to example 1 of the present invention 2 Graphs of electron conductivity and lithium ion diffusion coefficient of @ HPCNFs and the Sn @ HPCNFs flexible electrode prepared in example 2.
FIG. 12 is SnO in example 1 of the present invention 2 @ HPCNFs, Sn @ HPCNFs flexible electrode prepared in example 2, multiplying power performance diagram under different current densities.
FIG. 13 shows SnO in example 1 of the present invention 2 @ HPCNFs, Sn @ HPCNFs flexible electrode prepared in example 2, long cycle performance diagram at current density of 0.5A/g (a), 5A/g (b), respectively.
FIG. 14 is SnO in example 1 of the present invention 2 SEM image of @ HPCNFs Flexible electrode after 500 cycles of charging and discharging at 0.5A/g.
Fig. 15 is an SEM image of Sn @ HPCNFs flexible electrodes prepared in example 2 of the present invention.
FIG. 16 is a low resolution TEM image (a), HAADF-STEM image (b), and high resolution TEM image (c) of the Sn @ HPCNFs flexible electrode prepared in example 2 of the present invention.
FIG. 17 shows SnO prepared by example 1 of the present invention 2 And the EIS spectrogram of the Sn @ HPCNFs flexible electrode prepared in the example 2.
FIG. 18 is an SEM image of Sn @ HPCNFs flexible electrode in example 2 of the invention after 500 charge-discharge cycles at 5A/g.
Fig. 19 is an SEM image of Sn @ HPCNFs flexible electrodes prepared in example 3 of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. Of course, the specific embodiments described herein are merely illustrative of the invention and are not intended to be limiting.
The following examples further illustrate the present invention but are not to be construed as limiting the invention. Modifications or substitutions to methods, procedures, or conditions of the invention may be made without departing from the spirit and scope of the invention. The experimental methods and reagents of the formulations not specified in the examples are in accordance with the conventional conditions in the art.
The short letters referred to in the present embodiment are all fixed short letters in the art, and some of the short letters are explained as follows: SEM image: electronic scanning and image display; TEM image: scanning and developing an image by transmission electron; HRTEM image: high resolution transmission electron scanning image display; HAADF-STEM: a high-angle annular dark field scanning transmission electron microscope; EDS diagram: an element distribution map; XRD pattern: an X-ray diffraction pattern; XPS spectrum: analyzing a spectrogram by X-ray photoelectron spectroscopy; EIS: testing alternating current impedance; GITT: constant current intermittent titration test; SEI: a solid electrolyte interface film; SnO 2 @ HPCNFs: tin dioxide @ hollow porous carbon nanofiber; sn @ HPCNFs: tin @ hollow porous carbon nanofiber.
Example 1
0.5g of PMMA particles was added to 8mL of DMF solution, heated in a water bath at 60 ℃ and continuously stirred at 1500rpm for 1 hour until the PMMA particles were completely dissolved to prepare a mixed solution 1. 2.7g of PMMA particles were added to 9mL of DMF solution, and the mixture was heated in a water bath at 60 ℃ and stirred continuously at 1000rpm for 1 hour until the PMMA particles were completely dissolved to prepare a mixed solution 2.
1.5g PAN powder was added to the mixed solution 1, and 1g SnCl was added 2 ·2H 2 And adding the O particles into the mixed solution 2, heating in a water bath at 70 ℃, and continuously stirring at 1500rpm for 3 hours until the O particles are completely dissolved and mixed to form the core-shell spinning solution.
The prepared core-shell solution is respectively poured into a 10mL syringe, the syringe is connected into a coaxial metal needle (the outer diameter of the metal needle is 18G, the inner diameter of the metal needle is 22G), the flow rate of the core spinning solution is 0.015mL/min, the flow rate of the shell spinning solution is 0.030mL/min, the applied spinning voltage is 15kV, the receiving distance is 17cm, and the tinfoil is adopted for receiving. And spinning for 6 hours to obtain the electrostatic spinning fiber with a certain thickness. Note that the room temperature was kept around 25 ℃ and the humidity around 35%.
The obtained electrospun fiber was examined, and the results are shown in fig. 2, and fig. 2 is an SEM image of the electrospun fiber prepared in example 1 of the present invention, which has a diameter of about 820 nm.
Pre-oxidizing the electrostatic spinning fiber in an oven at the temperature rise rate of 5 ℃/min and the temperature of 250 ℃ for 2h, and finally obtaining SnO in argon atmosphere at the carbonization temperature of 450 DEG C 2 @ HPCNFs flexible electrode, the temperature rising and falling speed is 3 ℃/min, and the high-temperature carbonization time is 2 h.
Preparation of SnO for example 1 2 @ HPCNFs flexible electrodes for analysis:
wherein, FIG. 3 shows SnO prepared in example 1 of the present invention 2 SEM topography of @ HPCNFs flexible electrode. SnO 2 The @ HPCNFs flexible electrode has an average diameter of 550nm (FIG. 3a), a wall thickness of about 100nm and a hollow channel diameter of about 350nm (FIG. 3b), is favorable for shortening an ion or electron transmission path, improves electron conductivity, and can obviously observe that a plurality of irregular pores exist on the fiber wall.
FIG. 4 is SnO prepared according to example 1 of the present invention 2 @HPCNFsTEM, EDS images of the flexible electrode, further confirmed the presence of hollow structures and pore structures with different sizes were observed from the fibers (fig. 4 a). Furthermore, the inside of the fiber was uniformly distributed dark particles of size about 7nm (FIG. 4b), wherein the spacing of a set of parallel lattice stripes was 0.26nm, corresponding to SnO 2 Plane (101) of crystalline phase (fig. 5 c).
FIG. 5 is SnO prepared according to example 1 of the present invention 2 The XRD patterns of @ HPCNFs, Sn @ HPCNFs flexible electrode prepared in example 2. SnO 2 The @ HPCNFs flexible electrode shows a broad peak around 23.6 degrees, which indicates that the carbon nanofiber shell layer is amorphous carbon. Further, SnO 2 Diffraction peaks of the @ HPCNFs flexible electrode at the positions of 26.6 degrees, 33.8 degrees and 51.8 degrees can be well matched with SnO 2 (JCPDS NO.41-1445) standard diffraction card (110), (101), (211).
FIG. 6 is SnO prepared according to example 1 of the present invention 2 @ HPCNFs, XPS full spectrum of Sn @ HPCNFs flexible electrode prepared in example 2. C1s, O1s, N1 s, Sn 3p occur at 532.08, 398.08, 284.08, 759.08, 716.08, 495.08, 486.08 and 26.08eV 3/2 、Sn 3p 5/2 、Sn 3d 3/2 、Sn 3d 5/2 And diffraction peaks of Sn 4d, confirming SnO 2 C, N, O, Sn four constituent elements are present in the @ HPCNFs flexible electrode.
FIG. 7 is SnO prepared according to example 1 of the present invention 2 @ HPCNFs, and high resolution XPS spectra of C1s (a) and Sn 3d (b) of the Sn @ HPCNFs flexible electrode prepared in example 2. As can be seen from fig. 7a, the deconvolution of the C1s diffraction peak is divided into chemical bond states of C-C, C-N, C-O, C ═ N/C ═ O and Sn — C, located at 283.7, 284.3, 285.7, 288.1, 283.6eV, respectively, further demonstrating the successful doping of nitrogen atoms into the carbon matrix. In the composite material, the nitrogen-doped carbon nanofiber can improve the conductivity of the material and accelerate electron transmission. The presence of Sn-C bonds indicates SnO 2 And the HPCNFs form electronic coupling. SnO 2 The Sn-C bond composition in @ HPCNFs was 7.16%, which is probably due to SnO 2 The combination of Sn-O in the flexible electrode of @ HPCNFs is increased, so that the combination with the HPCNFs is reduced. FIG. 7b is a high resolution XPS spectrum of Sn 3d for a flexible electrode, deconvoluted to fourA single combined peak, two of which are Sn 3d 3/2 (494.5eV) and Sn 3d 5/2 A characteristic peak (486.1eV), and two small peaks corresponding to Sn — C bonds.
FIG. 8 is a SnO prepared in example 1 of the present invention 2 @ HPCNFs, Raman spectra of Sn @ HPCNFs flexible electrodes prepared in example 2. As shown, the flexible electrode showed two major Raman shift peaks, one of which was located at 1344cm -1 The vicinity is the D-peak band, due to the carbon atom with the defect, representing the degree of disorder of the structure. The other is located at 1585cm -1 The vicinity corresponds to the G peak band, due to sp 2 The in-plane stretching vibration of the hybridized carbon atom represents the graphitization degree of the structure. The peak intensity ratio (I) of the D band to the G band is usually set D /I G ) Used for evaluating the defects and the graphitization degree of the material. I is D /I G The larger the ratio of (a) is, the higher the graphitization degree of the flexible electrode is, and the flexible electrode has more defects and vacancies. Calculated by peak intensity, SnO 2 @ HPCNFs, I of s Flexible electrode D /I G Respectively 1.0.
FIG. 9 is a SnO prepared according to example 1 of the present invention 2 CV curves at different scan rates of 0.1 to 1mV/s for @ HPCNFs, Sn @ HPCNFs flexible electrodes prepared in example 2. It was found that the CV curve maintained a stable shape as the scan speed increased. Using the power law equation i ═ av b (a and b are variable parameters) to describe the relationship between peak current density (i) and scan rate (v). Thus, the b value is determined by the slopes of log (i) and log (v). Thus, by calculation, as shown in FIG. 10a, SnO 2 B values of @ HPCNFs flexible electrodes were 0.6 and close to 1, respectively, indicating SnO 2 The @ HPCNFs flexible electrode has a typical capacitive behavior. To further determine the capacitance ratio in the overall reaction, the formula i (v) ═ k 1 v+k 2 v 1/2 (i (V)) represents the current value at the selected potential, k 1 And k 2 Is a variable parameter). k is a radical of 1 v and k 2 v 1/2 Respectively representing DCP and SCP currents, by calculating k 1 And k 2 To quantify the capacitive contribution. FIG. 10b summarizes SnO 2 @ HPCNFs, Sn @ HPCNFs flexible electrode under different scanning ratesThe pseudocapacitance contribution of (a). SnO 2 The pseudo-capacitance contribution of the @ HPCNFs flexible electrode at 1.0mV/s was 78.9%.
FIG. 11 is SnO prepared according to example 1 of the present invention 2 @ HPCNFs, and the electron conductivity and lithium ion diffusion coefficient of the Sn @ HPCNFs flexible electrode prepared in example 2. Lithium ion diffusion coefficient was calculated by GITT test in combination with the following formula
Figure BDA0003718090100000071
The current density was set to 0.1A/g:
Figure BDA0003718090100000072
wherein n is m Is the number of moles, V m Is the molar volume, t is the relaxation time, S is the contact area of the electrode material and the electrolyte, Delta E s For pulse-induced voltage changes, Δ E t Voltage variation for constant current charging and discharging. During discharge at low current density, Li + At SnO 2 The average diffusion coefficient in @ HPCNFs Flexible electrodes was calculated to be 2.29X 10 -13 cm 2 S, indicating SnO 2 The @ HPCNFs flexible electrode has excellent ion diffusion performance at low current density, so that the flexible electrode has excellent reversible capacity at low current density. However, SnO 2 The electronic conductivity of the @ HPCNFs flexible electrode was only 2.22. mu.s/cm, which is probably due to SnO 2 The properties of the semiconductor itself limit its ability to charge and discharge rapidly.
FIG. 12 is SnO in example 1 of the present invention 2 @ HPCNFs, and an electrochemical performance test chart of the Sn @ HPCNFs flexible electrode prepared in example 2. SnO 2 Specific discharge capacities of the @ HPCNFs flexible electrode at 0.05, 0.1, 0.2, 0.5, 1, 2 and 5A/g are 1084.2, 849.9, 733.3, 586.2, 440.3, 267.4 and 102.1mAh/g respectively, and the flexible electrode exhibits ultrahigh specific discharge capacity. When the current density is recovered to 0.05A/g, the discharge specific capacity is 879.1mAh/g, and the capacity retention rate is 81.1%. SnO at low current density of 0.05A/g due to faster lithium ion diffusion rate and higher lithium ion adsorption capacity 2 @HPCNFThe specific discharge capacity (1084.2mAh/g) of the s electrode is higher than that (829.9mAh/g) of the Sn @ HPCNFs flexible electrode. Further, SnO 2 The @ HPCNFs flexible electrode still maintains 1191.5mAh/g excellent specific discharge capacity after being cycled for 200 times under the low current density of 0.5A/g (figure 13 a).
FIG. 14 is SnO in example 1 of the present invention 2 SEM pictures of @ HPCNFs after 500 cycles of charge and discharge at 0.5A/g. The particles shown in the figure are conductive carbon black and other additives required for preparing the battery negative electrode. As can be seen from the figure, after 500 times of charge-discharge cycles, the composite electrode still maintains the original fiber structure, no crack appears on the surface, and a layer similar to a film is wrapped on the outer layer of the fiber. This may be an irreversible reaction occurring when the electrode surface is in contact with the electrolyte during the cycle, thereby forming a passivation film (SEI film) on the surface.
Example 2
0.5g of PMMA particles was added to 8mL of DMF solution, heated in a water bath at 60 ℃ and continuously stirred at 1500rpm for 1 hour until the PMMA particles were completely dissolved to prepare a mixed solution 1. 2.7g of PMMA particles were added to 9mL of DMF solution, and the mixture was heated in a water bath at 60 ℃ and stirred continuously at 1000rpm for 1 hour until the PMMA particles were completely dissolved to prepare a mixed solution 2.
1.5g PAN powder was added to the mixed solution 1, 1g SnCl 2 ·5H 2 And adding the O particles into the mixed solution 2, heating in a water bath at 70 ℃, and continuously stirring at 1500rpm for 3 hours until the O particles are completely dissolved and mixed to form the core-shell spinning solution.
The prepared core-shell solution is respectively poured into a 10mL syringe, the syringe is connected into a coaxial metal needle (the outer diameter of the metal needle is 18G, the inner diameter of the metal needle is 22G), the flow rate of the core spinning solution is 0.015mL/min, the flow rate of the shell spinning solution is 0.030mL/min, the applied spinning voltage is 15kV, the receiving distance is 17cm, and the tinfoil is adopted for receiving. And spinning for 6 hours to obtain the electrostatic spinning fiber with a certain thickness. Note that the room temperature was kept around 25 ℃ and the humidity around 35%.
Pre-oxidizing the electrostatic spinning fiber in an oven at the temperature rise rate of 5 ℃/min and the temperature of 250 ℃ for 2h, finally obtaining the Sn @ HPCNFs flexible electrode in the argon atmosphere at the carbonization temperature of 850 ℃, and raising and lowering the temperatureThe speed is 3 ℃/min, and the high-temperature carbonization time is 2 h. SnO prepared from embodiment 1 2 @ HPCNFs Flexible electrode for comparison
The Sn @ HPCNFs flexible electrode prepared in example 2 was analyzed:
fig. 15 is an SEM topography of the Sn @ HPCNFs flexible electrode prepared in example 2 of the present invention. When the carbonization temperature is further increased to 850 ℃, the Sn @ HPCNFs flexible electrode also has the same hollow porous structure. In addition, the fibers further shrunk due to the increased carbonization temperature, and had an average diameter of 560nm and a wall thickness of about 116 nm.
FIG. 16 is a TEM, HAADF-STEM, HRTEM and EDS image of Sn @ HPCNFs flexible electrode prepared in example 2 of the present invention. Fig. 16a shows that the flexible electrode has the same hollow and porous structure. FIG. 16b is the HAADF-STEM diagram of the Sn @ HPCNFs flexible electrode. As shown in the figure, it can be clearly observed that bright spots of two sizes are uniformly dispersed in the carbon nanofibers, both corresponding to the Sn nanoclusters, with an average size of about 2 nm. The small-size nanoclusters are more favorable for improving the reaction kinetics of the electrodes and realizing the rapid charge storage capacity. FIG. 16c is a TEM image of an amorphous carbon shell layer of the Sn @ HPCNFs composite electrode. It can be seen from the enlarged inset that the amorphous carbon shell of the carbon nanofiber shows many lattice fringes. The lattice fringe spacing is 0.34nm, corresponding to the (002) crystal face of the graphitized carbon. The formed graphitized carbon shell layer is beneficial to electron transfer, so that the composite electrode has better conductivity.
FIG. 5 is SnO prepared according to example 1 of the present invention 2 The XRD patterns of @ HPCNFs, Sn @ HPCNFs flexible electrode prepared in example 2. After high-temperature carbonization at 850 ℃ in a nitrogen atmosphere, all diffraction peaks of the Sn @ HPCNFs flexible electrode are completely matched with a standard diffraction card of positive tetragonal tin (JCPDSNO.04-0673). In addition, no obvious amorphous carbon broad peak is observed near 26 degrees of the Sn @ HPCNFs composite electrode, and probably due to the fact that the Sn crystal form is improved by the high carbonization temperature, the strong diffraction peak intensity is shown, and the diffraction peak of carbon is weakened.
FIG. 6 is SnO prepared according to example 1 of the present invention 2 @ HPCNFs, Sn @ HPCNFs prepared in example 2, and XPS full spectrograms of HPCNFs flexible electrodes. At 532.08, 398.08, 284.08495.08, 486.08 and 26.08eV C1s, O1s, N1 s, Sn 3d 3/2 、Sn 3d 5/2 And diffraction peaks of Sn 4d, confirming the presence of C, N, O, Sn four constituent elements in the Sn @ HPCNFs flexible electrode. In addition, it is also apparent that the intensity of the O1s diffraction peak of the Sn @ HCNFs flexible electrode is dramatically reduced. The SnO after high-temperature carbonization treatment at the temperature of above 850 DEG C 2 Gradually reduced to Sn, so that a large amount of oxygen functional groups on the surface of the Sn @ HCNFS flexible electrode are removed.
FIG. 7 is SnO prepared according to example 1 of the present invention 2 @ HPCNFs, and high resolution XPS spectra of C1s (a) and Sn 3d (b) of the Sn @ HPCNFs flexible electrode prepared in example 2. As can be seen from FIG. 7a, as the carbonization temperature increases, the Sn-C content increases (SnO) 2 @ HPCNFs 7.16%, Sn @ HPCNFs 12.22%), which is probably due to SnO 2 The combination of Sn-O in the flexible electrode of @ HPCNFs is increased, so that the combination with the HPCNFs is reduced. The high interfacial bond strength between Sn and HPCNFs has a positive impact on lithium storage performance. SnO prepared from example 1 2 The Sn 3d diffraction peak of @ HPCNFs was shifted to higher binding energy than that of the flexible electrode of Sn @ HPCNFs, and the formed Sn-C showed a larger diffraction peak intensity (FIG. 7 b).
FIG. 8 is a SnO prepared according to example 1 of the present invention 2 @ HPCNFs, Raman spectra of Sn @ HPCNFs flexible electrodes prepared in example 2. Calculated by peak intensity, SnO 2 I of @ HPCNFs, Sn @ HPCNFs flexible electrode D /I G The surface roughness is 1.17, which shows that the Sn @ HPCNFs flexible electrode has high graphitization degree, has more defects and vacancies, is favorable for improving the conductivity of the flexible electrode, and further improves the electrochemical performance of the flexible electrode.
FIG. 9 is SnO prepared according to example 1 of the present invention 2 CV curves at different scan rates of 0.1 to 1mV/s for @ HPCNFs, Sn @ HPCNFs flexible electrodes prepared in example 2. It was found that the CV curve maintained a stable shape as the scan speed increased. Similarly, by the power law formula i ═ av b Calculated, as shown in FIG. 14a, the b value of the Sn @ HPCNFs flexible electrode is 0.76, which is close to 1, and shows SnO 2 @ HPCNFs, Sn @ HPCNFs Flexible electrodes have typical capacitive behavior. By the formula i (V) ═ k 1 v+k 2 v 1/2 ComputingThe result shows that the pseudocapacitance contribution (98.2%) of the Sn @ HPCNFs flexible electrode at 1.0mV/s is far higher than that of SnO 2 @ HPCNFs (78.9%) proves that the Sn @ HPCNFs flexible electrode has excellent rapid charge-discharge capacity under high-rate current density.
FIG. 10 is SnO prepared according to example 1 of the present invention 2 @ HPCNFs, and the electron conductivity and lithium ion diffusion coefficient of the Sn @ HPCNFs flexible electrode prepared in example 2. As shown, the Sn @ HPCNFs flexible electrode (4.52 μ s/cm) exhibits a specific SnO 2 The flexible electrode @ HPCNFs (2.22 mus/cm) has higher electronic conductivity, which is due to the inherent high electronic conductivity of Sn and the improved conductivity after high-temperature carbonization, and the Sn @ HPCNFs are endowed with rapid charging capability. All the materials contribute to the fact that the quick charging performance of the Sn @ HPCNFs flexible electrode is higher than that of SnO 2 @ HPCNFs flexible electrodes.
FIG. 17 shows SnO in example 1 of the present invention 2 The EIS diagram of @ HPCNFs and Sn @ HPCNFs flexible electrode prepared in example 2 was measured after 200 cycles at a current density of 1A/g. As shown, each EIS curve consists of two parts: high frequency region semicircle and low frequency region slash. The semicircle of the high frequency region is related to electron transfer and represents the charge transfer resistance (R) ct ). The slope of the low frequency line is related to lithium ion diffusion in the electrode and is called Warburg impedance. Obviously, the semicircular shape of the Sn @ HPCNFs flexible electrode is far smaller than that of SnO 2 @ HPCNFs, which is because of the high degree of graphitization that improves conductivity, while N-doped carbon nanofibers possess abundant defects and vacancies that facilitate lithium ion diffusion.
FIG. 12 is SnO in example 1 of the present invention 2 @ HPCNFs, Sn @ HPCNFs flexible electrode prepared in example 2. The specific discharge capacities of the Sn @ HPCNFs flexible electrode at 0.05, 0.1, 0.2, 0.5, 1, 2 and 5A/g are 829.9, 665.7, 603.2, 525.4, 426.8, 338.2 and 238.8mAh/g respectively, and the flexible electrode shows ultrahigh specific discharge capacity. When the current density is recovered to 0.05A/g, the discharge specific capacity is 656.3mAh/g, and the capacity retention rate is 79%. When the current density is increased to 5A/g, the Sn @ HPCNFs flexible electrode shows 238.8mAh/g high-rate performance which is far higher than SnO 2 @ HPCNFs (123.7mAh/g), due to charge transfer resistance reductionSmall and enhanced conductivity. In addition, after the Sn @ HPCNFs flexible electrode is subjected to charge-discharge circulation for 200 times under the condition of high current density of 5A/g, the high specific capacity of 266mAh/g is still displayed, the capacity retention rate is 100 percent and is higher than SnO 2 @ HPCNFs Flexible electrode (185.7mAh/g) (FIG. 13b)
FIG. 18 is an SEM image of Sn @ HPCNFs flexible electrode in example 1 of the invention after 500 charge-discharge cycles at 5A/g. As shown in the figure, after 500 charge-discharge cycles, the Sn @ HPCNFs flexible electrode still maintains the original fiber structure, and a layer of SEI film uniformly grows on the surface.
In conclusion, the test results show that the preparation method provided by the invention successfully prepares the tin or tin dioxide @ hollow porous carbon nanofiber flexible electrode (SnO) 2 @ HPCNFs or Sn @ HPCNFs), simple and easy to operate, and forms hollow porous fibers by coaxial electrospinning and a carbonization-reduction technology, and SnO is generated by oxidation-reduction in the inner wall of a fiber cavity 2 Or Sn. The 3D network formed by the N-doped carbon nanofiber provides a continuous transmission channel for lithium ions and electrons, reduces the diffusion energy barrier of the lithium ions, and improves the diffusion rate. The internal sufficient free space and the external large amount of pores can effectively relieve SnO 2 Or the stress change caused by the volume expansion of Sn in the charging and discharging process further shortens the diffusion path of lithium ions, increases the charge transfer and reaction kinetics and is beneficial to forming a stable SEI layer. Through this unique structural design, SnO 2 The @ HPCNFs and the Sn @ HPCNFs flexible electrode both show excellent rate capability and cycle performance. At a low carbonization temperature of<SnO synthesized at 500 ℃) 2 The @ HPCNFs flexible electrode has high capacity at low current densities. In addition, at a high carbonization temperature (>The Sn @ HPCNFs flexible electrode synthesized at 500 ℃ shows better electrochemical performance at high current density. The research of SnO by adjusting the carbonization temperature 2 And Sn, the development of energy storage systems can be pursued for strategies to build high energy density and fast charge and discharge electrodes.
Example 3
(1) 0.6g of PS particles was added to 9mL of DMF solution, heated in a water bath at 70 ℃ and continuously stirred at 1500rpm for 2 hours until the PMMA particles were completely dissolved to prepare a mixed solution 1. 0.8g of PS particles was added to 12mL of DMF solution, and the mixture was heated in a water bath at 70 ℃ and stirred continuously at 1000rpm for 2 hours until the PS particles were completely dissolved to prepare a mixed solution 2.
(2) 1.2g PAN powder was added to the mixed solution 1, and 0.15g C was added 4 H 6 O 4 And adding the Sn particles into the mixed solution 2, respectively heating in a water bath at 75 ℃, and continuously stirring at 1500rpm for 5h until the Sn particles are completely dissolved and mixed to form the core-shell spinning solution.
(3) The prepared core-shell solutions were poured into 10mL syringes, respectively, and connected to coaxial metal needles (the outer diameter of the metal needle was 18G, the inner diameter was 23G), the core spinning solution flow rate was 0.01mL/min, the shell spinning solution flow rate was 0.015mL/min, the applied spinning voltage was 16kV, the receiving distance was 17cm, and the receiving was performed with tinfoil. And spinning for 6 hours to obtain the electrostatic spinning fiber with a certain thickness. Note that the room temperature was kept around 25 ℃ and the humidity around 35%.
(4) The electrostatic spinning fiber is pre-oxidized for 3 hours at 300 ℃ in an oven at the heating rate of 6 ℃/min, and finally, the hollow porous tin @ carbon (Sn @ HPCNFs) flexible electrode is obtained through high-temperature carbonization, wherein the atmosphere is argon, the carbonization temperature is 600 ℃, the heating and cooling rate is 2 ℃/min, and the high-temperature carbonization time is 3 hours. And directly cutting the carbonized electrostatic spinning film into a wafer with the diameter of 10mm as an electrode material to assemble the lithium ion battery.
(5) By analyzing the Sn @ HPCNFs flexible electrode prepared in the embodiment 3 of the invention, the result is shown in FIG. 19, the obtained fiber is of a hollow structure, the average diameter of the fiber is 400-800nm, and the wall thickness is 70-200 nm.
The above description is only a preferred embodiment of the present invention, and should not be taken as limiting the invention, and any local variations in the formulation and process thereof should be considered within the scope of the present invention.

Claims (10)

1. A preparation method for preparing a tin or tin dioxide @ hollow porous carbon nanofiber flexible electrode by regulating and controlling the carbonization temperature is characterized by comprising the following steps of:
the method comprises the following steps: preparing a core-shell spinning solution: dispersing a thermoplastic high polymer material in N, N-Dimethylformamide (DMF) solution, heating and continuously stirring for a period of time until particles are completely dissolved to form mixed solution, respectively adding a tin source precursor and Polyacrylonitrile (PAN) powder into the mixed solution, heating and continuously stirring for a period of time until the tin source precursor and the Polyacrylonitrile (PAN) powder are completely dissolved to form core-shell spinning solution;
step two: SnO 2 Preparing flexible electrodes of @ HPCNFs and Sn @ HPCNFs: respectively filling the core-shell spinning solution into an injector, carrying out electrostatic spinning through a coaxial electrostatic spinning device to obtain electrostatic spinning fibers, carrying out pre-oxidation treatment on the electrostatic spinning fibers in the air atmosphere to stabilize the fiber structure, then carrying out different carbonization temperature treatments on the pre-oxidized electrostatic spinning fibers, and finally obtaining SnO 2 @ HPCNFs and Sn @ HPCNFs flexible electrode;
step three: SnO 2 Testing the electrochemical performance of the flexible electrode of @ HPCNFs and Sn @ HPCNFs: the flexible electrode is used as a pole piece to assemble the lithium ion battery, the cycle performance and the multiplying power performance of the battery are tested, and the electrochemical performance of the battery is obtained by performing cyclic voltammetry test, alternating current impedance test and constant current intermittent titration test.
2. The preparation method of the tin or tin dioxide @ hollow porous carbon nanofiber flexible electrode according to claim 1, wherein the thermoplastic polymer material in the first step is one or a combination of polymethyl methacrylate (PMMA) and Polystyrene (PS), and the weight ratio of the thermoplastic polymer material to the DMF solution is 1: 1-20.
3. The preparation method of the tin or tin dioxide @ hollow porous carbon nanofiber flexible electrode by regulating and controlling the carbonization temperature as claimed in claim 1, wherein in the first step, the heating temperature is 20-100 ℃, the heating time is 1-10h, and the stirring speed is 10-1500 rpm.
4. Preparation of tin or tin bis according to claim 1 by controlling the carbonization temperatureThe preparation method of the tin oxide @ hollow porous carbon nanofiber flexible electrode is characterized in that in the step one, a tin source precursor is SnCl 2 ·2H 2 O、SnCl 2 ·5H 2 O、C 4 H 6 O 4 Sn、C 2 O 4 Sn, wherein the weight ratio of the tin source precursor to the mixed solution is 1: 1-20.
5. The preparation method of the tin or tin dioxide @ hollow porous carbon nanofiber flexible electrode through regulation and control of the carbonization temperature in the step one, which is characterized in that the weight ratio of the PAN powder to the mixed solution in the step one is 1:1-15, the heating temperature is 20-100 ℃ during stirring, the heating time is 2-20h, and the stirring speed is 10-1500 rpm.
6. The method for preparing the tin or tin dioxide @ hollow porous carbon nanofiber flexible electrode according to claim 1, characterized in that in the electrospinning process in the second step, the capacity of an injector is 5-100mL, the diameter of an inner needle of a coaxial metal needle is 0.3-0.9mm, and the diameter of an outer needle is 0.9-2.8 mm.
7. The preparation method for preparing the tin or tin dioxide @ hollow porous carbon nanofiber flexible electrode by regulating and controlling the carbonization temperature as claimed in claim 1, wherein in the electrostatic spinning process in the second step, the voltage is set to be 10-20kV, the flow rate of the core spinning solution is 0.1-0.2mL/min, the flow rate of the shell spinning solution is 0.1-0.5mL/min, the receiving distance is 10-20cm, and the spinning time is 1-24 hours;
in the electrostatic spinning process in the second step, the temperature is 15-30 ℃, and the humidity is 20-50%;
the temperature of pre-oxidation in the second step is 100-;
the carbonization temperature in the second step is 400-.
8. The method for preparing the tin or tin dioxide @ hollow porous carbon nanofiber flexible electrode by regulating and controlling the carbonization temperature as claimed in claim 1, wherein the step three of directly using the flexible electrode as the pole piece is to cut the flexible electrode into a disk with a diameter of 10mm and a mass of 0.3-10 mg.
9. The method for preparing the tin or tin dioxide @ hollow porous carbon nanofiber flexible electrode by regulating and controlling the carbonization temperature as claimed in claim 1, wherein the test voltage range of the half cell in the third step is 0.01-4V, the magnitude of the charge and discharge current is 0.05-20A/g, the cycle number is 100-6000 cycles, the scanning rate of the cyclic voltammetry test is 0.1-100mV/s, and the voltage range is 0.01-4V.
10. The preparation method for preparing the tin or tin dioxide @ hollow porous carbon nanofiber flexible electrode according to claim 1, wherein the frequency range of EIS test in the third step is 0.01-10 6 Hz, voltage amplitude of 1-10mV, current density range of 0.1-10A/g, voltage range of 0.01-4V, and charging and discharging time of 10-120 min.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115911382A (en) * 2022-11-29 2023-04-04 江阴普朗克科技有限公司 Foamed nickel self-supporting SnO 2 Nano-array @ porous carbon fiber composite material and preparation method and application thereof

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101626075A (en) * 2009-08-03 2010-01-13 北京化工大学 Stannum and carbon composite nano-fiber film negative-electrode material and preparation method thereof
CN104319372A (en) * 2014-11-14 2015-01-28 湖南大学 Convenient method for preparing binder-free stannic oxide/carbon fibrofelt for negative pole of high-performance lithium ion battery
CN109638234A (en) * 2018-11-08 2019-04-16 华南理工大学 One-dimensional porous antimony base functional carbon nanotubes of one kind and its preparation method and application
CN109921002A (en) * 2019-03-27 2019-06-21 珠海光宇电池有限公司 A kind of preparation method of anode material of lithium-ion battery
CN114220958A (en) * 2021-12-08 2022-03-22 南通大学 Preparation method of flexible composite electrode with hollow porous carbon @ zinc oxide @ carbon nanofiber

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101626075A (en) * 2009-08-03 2010-01-13 北京化工大学 Stannum and carbon composite nano-fiber film negative-electrode material and preparation method thereof
CN104319372A (en) * 2014-11-14 2015-01-28 湖南大学 Convenient method for preparing binder-free stannic oxide/carbon fibrofelt for negative pole of high-performance lithium ion battery
CN109638234A (en) * 2018-11-08 2019-04-16 华南理工大学 One-dimensional porous antimony base functional carbon nanotubes of one kind and its preparation method and application
CN109921002A (en) * 2019-03-27 2019-06-21 珠海光宇电池有限公司 A kind of preparation method of anode material of lithium-ion battery
CN114220958A (en) * 2021-12-08 2022-03-22 南通大学 Preparation method of flexible composite electrode with hollow porous carbon @ zinc oxide @ carbon nanofiber

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115911382A (en) * 2022-11-29 2023-04-04 江阴普朗克科技有限公司 Foamed nickel self-supporting SnO 2 Nano-array @ porous carbon fiber composite material and preparation method and application thereof
CN115911382B (en) * 2022-11-29 2023-09-05 江阴普朗克科技有限公司 Self-supporting SnO of foam nickel 2 Nano array@porous carbon fiber composite material and preparation method and application thereof

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