Amorphous negative electrode material of battery, preparation method of amorphous negative electrode material and battery

Abstract

The invention discloses a battery amorphous negative electrode material, a preparation method of the battery amorphous negative electrode material and a battery, and belongs to the technical field of new energy, and the preparation method of the battery amorphous negative electrode material comprises the following steps: stirring polyacrylonitrile and dimethylformamide under a first preset condition to obtain a sol-gel solution; adding bismuth salt and antimony salt into the sol-gel solution, and stirring for a preset time to uniformly disperse the bismuth salt and the antimony salt to obtain a sol-gel solution containing metal ions; performing electrostatic spinning on the sol-gel solution containing the metal ions under a second preset condition to obtain a film precursor material; carrying out pre-oxidation treatment on the film precursor material in air to obtain a pre-treated material; performing carbonization and reduction treatment on the pretreated material under a third preset condition to obtain a carbonized material; the carbonized material is subjected to vulcanization treatment, and the carbon fiber wrapped nano-alloy material is obtained; and heating and pressurizing the carbon fiber coated nano-alloy material to obtain the carbon fiber coated amorphous nano-alloy sulfide material.

Description

Technical Field

[0001] This application belongs to the technical field of new energy, and particularly relates to a battery amorphous anode material, a preparation method thereof, and a battery. Background Art

[0002] Electrified new energy vehicles are the future development direction of the automotive market, and their core component is an alkali metal ion battery. With the development of the market, the demand for batteries with high capacity density is increasing. Adopting new high specific capacity anode and cathode materials is one of the important methods to improve the energy density of the battery. More and more new materials such as metals, metal alloys, and sulfides are used as active materials in the anode material to continuously explore various ways to improve the energy density of the battery. Taking alloy and metal sulfide anode materials as an example, Sb-based alloy (theoretical specific capacity 660 mA / g) and Sb-based sulfide (947 mA / g) anode materials, as one of the above active materials, are generally regarded as the next-generation anode materials.

[0003] However, whether it is Sb-based alloy or Sb-based sulfide anode material, a large volume change (>400%) occurs during the potassium / lithium insertion process. This not only causes problems such as cracking of the electrode material, structural damage, increased side reactions due to the electrolyte entering the material cracks, thickening of the solid electrolyte interface film (SEI film), and increased interface impedance, but also poses a severe challenge to the safety of the battery system. Summary of the Invention

[0004] The purpose of this application is to provide a battery amorphous anode material, a preparation method thereof, and a battery to improve problems such as large volume expansion and polysulfide shuttle during potassium / lithium storage in the anode material.

[0005] According to the first aspect of the embodiments of this application, a preparation method of a battery amorphous anode material is provided. The method may include:

[0006] Stir polyacrylonitrile and dimethylformamide under a first preset condition to obtain a sol-gel solution;

[0007] Add bismuth salt and antimony salt into the sol-gel solution, and stir for a preset time to disperse them evenly to obtain a sol-gel solution containing metal ions;

[0008] Perform electrospinning on the sol-gel solution containing metal ions under a second preset condition to obtain a thin film precursor material;

[0009] Perform pre-oxidation treatment on the thin film precursor material in the air to obtain a pre-treated material;

[0010] Perform carbonization and reduction treatment on the pre-treated material under a third preset condition to obtain a carbonized material;

[0011] The carbonized material is sulfided to obtain a carbon fiber-wrapped nano-alloy material;

[0012] The carbon fiber-wrapped nano-alloy material is subjected to heating and pressurization treatment to obtain a carbon fiber-wrapped amorphous nano-alloy sulfide material.

[0013] In some alternative embodiments of the present application, the mass-volume ratio of polyacrylonitrile to dimethylformamide is 0.4-1.5 g: 10 mL;

[0014] The mass ratio of polyacrylonitrile to the total mass of bismuth salt and antimony salt is 0.1-5.

[0015] In some alternative embodiments of the present application, the bismuth salt and the antimony salt are one or a combination of chloride, sulfate, nitrate, and acetate.

[0016] In some alternative embodiments of the present application, the preset time is 4-48 h.

[0017] In some alternative embodiments of the present application, the second preset condition includes:

[0018] The flow rate of the sol-gel solution is 0.5 mL / h-1.2 mL / h;

[0019] The distance from the metal needle of the electrospinning to the metal plate is 8-30 cm.

[0020] In some alternative embodiments of the present application, the temperature of the pre-oxidation treatment is 200-300 °C;

[0021] The time of the pre-oxidation treatment is 6 h.

[0022] In some alternative embodiments of the present application, the third preset condition includes:

[0023] The pretreated material is placed in a mixed gas of Ar and H2;

[0024] The time of carbonization and reduction treatment is 2-12 h.

[0025] In some alternative embodiments of the present application, the conditions of the sulfidation treatment include:

[0026] The ratio of the carbonized material to sulfur is 1: 3-20;

[0027] The sulfidation temperature is 400-600 °C;

[0028] The sulfidation time is 1-5 h.

[0029] According to the second aspect of the embodiments of the present application, a battery amorphous anode material is provided, and the battery amorphous anode material is prepared by using the preparation method of the battery amorphous anode material according to any one of the embodiments of the first aspect.

[0030] According to a third aspect of an embodiment of the present application, a battery is provided, and the material of the negative electrode of the battery is the amorphous negative electrode material of the battery described in the embodiment of the second aspect.

[0031] The above technical solution of the present application has the following beneficial technical effects:

[0032] The method of the embodiment of the present application can obtain a carbon fiber-wrapped amorphous nanoparticle negative electrode material. By amorphizing the negative electrode material, due to the unique structure and properties of the amorphous, such as isotropy, high elasticity, tensile strength, structural strength, and chemical stability. At the same time, the increase in disorder can effectively enhance the electrode morphology and structural stability during the electrochemical process, thereby improving the cycle stability of the battery prepared from the negative electrode material. In addition, the method has simple process, simple equipment operation, low cost, high success rate of product preparation, and is green and environmentally friendly, suitable for large-scale commercial production. Description of the Drawings

[0033] Figure 1 is a schematic flow chart of a method for preparing an amorphous negative electrode material of a battery in an exemplary embodiment of the present application;

[0034] Figure 2 is a transmission electron microscope (TEM) image of a carbon fiber-wrapped amorphous nanoalloy sulfide material in an exemplary embodiment of the present application;

[0035] Figure 3 is a charge-discharge curve graph of a carbon fiber-wrapped amorphous nanoalloy sulfide material in an exemplary embodiment of the present application;

[0036] Figure 4 is a cyclic stability performance graph of a carbon fiber-wrapped amorphous nanoalloy sulfide material in an exemplary embodiment of the present application;

[0037] Figure 5 is a transmission electron microscope (TEM) image of a carbon fiber-wrapped nanoalloy sulfide material in an exemplary embodiment of the present application;

[0038] Figure 6 is a charge-discharge curve graph of a carbon fiber-wrapped nanoalloy sulfide material in an exemplary embodiment of the present application;

[0039] Figure 7 is a cyclic stability performance graph of a carbon fiber-wrapped nanoalloy sulfide material in an exemplary embodiment of the present application. Detailed Embodiments

[0040] To make the objectives, technical solutions and advantages of the present application more clear and understandable, the present application will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present application. In addition, in the following descriptions, the descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present application.

[0041] The schematic diagram of the layer structure according to an embodiment of the present application is shown in the accompanying drawings. These figures are not drawn to scale, where for the purpose of clarity, some details are enlarged and some details may be omitted. The various regions, shapes of the layers shown in the figures, as well as their relative sizes and positional relationships are merely exemplary. In practice, there may be deviations due to manufacturing tolerances or technical limitations, and those skilled in the art can design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0042] Obviously, the described embodiments are some embodiments of the present application, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the scope of protection of the present application.

[0043] In the description of the present application, it should be noted that the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0044] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0045] A battery amorphous anode material, its preparation method, and a battery provided by an embodiment of the present application will be described in detail below in conjunction with the accompanying drawings, through specific embodiments and their application scenarios.

[0046] As Figure 1 shown, in the first aspect of the embodiment of the present application, a preparation method of a battery amorphous anode material is provided, and the method may include:

[0047] S110: Stir polyacrylonitrile and dimethylformamide under a first preset condition to obtain a sol-gel solution;

[0048] S120: Add bismuth salt and antimony salt into the sol-gel solution, and stir for a preset time to disperse them evenly to obtain a sol-gel solution containing metal ions;

[0049] S130: Perform electrospinning on the sol-gel solution containing metal ions under a second preset condition to obtain a thin film precursor material;

[0050] S140: Pre-oxidize the thin film precursor material in air to obtain a pre-treated material;

[0051] S150: Carbonize and reduce the pre-treated material under a third preset condition to obtain a carbonized material;

[0052] S160: Sulfurize the carbonized material to obtain a carbon fiber-wrapped nano-alloy material;

[0053] S170: Subject the carbon fiber-wrapped nano-alloy material to a heating and pressurizing treatment to obtain a carbon fiber-wrapped amorphous nano-alloy sulfide material.

[0054] The method of the embodiment of the present application can obtain a carbon fiber-wrapped amorphous nanoparticle anode material. By amorphizing the anode material, due to the unique structure and properties of the amorphous, such as isotropic, high elasticity, tensile strength, structural strength, and chemical stability. At the same time, the increase in disorder can effectively enhance the electrode morphology and structural stability during the electrochemical process, thereby improving the cycle stability of the battery prepared from this anode material. In addition, this method has a simple process, simple equipment operation, low cost, a high success rate of product preparation, and is green and environmentally friendly, suitable for large-scale commercial production.

[0055] In this embodiment, the chemical formula of the carbon fiber-wrapped amorphous nano-alloy sulfide material can be expressed as a-(Bi,Sb)2S3@C. Through the synergistic effect of the amorphous and the binary metal, the large volume expansion and polysulfide shuttle generated during the charge and discharge process can be effectively inhibited, and excellent cycle stability is presented. And this anode material combines the respective advantages of the conversion and alloy reactions. On the one hand, it ensures a high reversible specific capacity based on the multi-electron transfer reaction. On the other hand, it enhances the structural stability through the amorphous potassium storage mechanism.

[0056] In some embodiments, the mass-volume ratio of polyacrylonitrile to dimethylformamide is 0.4 - 1.5 g: 10 mL;

[0057] The mass ratio of polyacrylonitrile to the total mass of bismuth salt and antimony salt is 0.1 - 5.

[0058] If the solution concentration of electrospinning is too high, the spun fibers will be too thick and easily clog the needle holes. If the concentration is too low, no colloid will be formed and the electrospinning will fail. If the metal salt content is too high, the spun particles will be large. If the content is too low, the capacity of the battery will be low. The best effect can be achieved within the scope of this embodiment.

[0059] In some embodiments, the bismuth salt and the antimony salt are one or more combinations of chlorides, sulfates, nitrates, and acetates.

[0060] In some embodiments, the preset time is 4 - 48 h.

[0061] Insufficient stirring time results in poor capacity uniformity. Overlong stirring easily causes water absorption, leading to the failure of the spinning solution. Within the scope of this embodiment, the spinning effect can be optimized.

[0062] In some embodiments, the second preset condition includes:

[0063] The flow rate of the sol-gel solution is 0.5 mL / h to 1.2 mL / h;

[0064] The distance from the metal needle of the electrospinning to the metal plate is 8 to 30 cm.

[0065] Too low a flow rate leads to unstable electrospinning, and too high a flow rate causes the solution to vertically drop at the needle tip, forming an unstable wire-drawing environment. If the distance from the metal needle to the metal plate is too close, the electrospinning membrane is easily punctured, and if the distance is too far, the metal plate cannot receive the wire.

[0066] In some embodiments, the temperature of the pre-oxidation treatment is 200 to 300 °C;

[0067] The time of the pre-oxidation treatment is 6 h.

[0068] Too low an oxidation temperature results in poor oxidation effect, and too high a temperature causes the carbon fiber to burn and damage the material. The best effect can be achieved within the parameter range of this embodiment.

[0069] In some embodiments, the third preset condition includes:

[0070] Place the pretreated material in a mixed gas of Ar and H2;

[0071] The time of carbonization and reduction treatment is 2 to 12 h.

[0072] In this embodiment, the Ar / H2 mixed gas plays a role in protecting and reducing the precursor material. Too short a carbonization time results in incomplete carbonization, and too long a carbonization time causes stress concentration and cracks inside the material.

[0073] In some embodiments, the conditions of the sulfidation treatment include:

[0074] The ratio of the carbonized material to sulfur is 1:3 to 20;

[0075] The sulfidation temperature is 400 to 600 °C;

[0076] The sulfidation time is 1 to 5 h.

[0077] Too low a sulfidation temperature results in incomplete sulfides, and too high a sulfidation temperature causes the sulfur on the material surface to easily escape.

[0078] In some embodiments, the pressurized gas for the heating and pressurizing treatment is an inert protective gas, such as argon or nitrogen, and the heating and pressurizing treatment time is 2 to 48 hours. A low heating temperature, no pressure, and a short treatment time are not conducive to the reaction, while an excessive temperature causes unnecessary energy waste.

[0079] In the second aspect of the embodiments of the present application, a battery amorphous anode material is provided, and the battery amorphous anode material is prepared by using the preparation method of the battery amorphous anode material according to any one of the embodiments of the first aspect.

[0080] In the third aspect of the embodiments of the present application, a battery is provided, and the material of the negative electrode of the battery is the battery amorphous anode material according to the embodiments of the second aspect.

[0081] Example 1:

[0082] (1) Dissolve 0.5 mmol of bismuth nitrate and 1.5 mmol of antimony acetate in 5.5 mL of DMF solvent. Then add 0.25 g of PAN to prepare an electrospinning sol-gel solution. The electrospinning parameters are: 15 kV, 1 mL / h, and the distance between the needle and the receiver is 20 cm;

[0083] (2) Collect the electrospun fiber film material and heat it in a muffle furnace at a heating rate of 2 °C / min and keep it at 280 °C for 6 hours. Then, put it into a tubular furnace under an Ar / H2 mixed atmosphere and further carbonize it at a heating rate of 2 °C / min at 600 °C for 6 hours to obtain (Bi,Sb)@C. Sulfurize the carbon fiber-wrapped nanoalloy material to obtain a carbon fiber-wrapped nanoalloy sulfide material (Bi,Sb)2S3@C;

[0084] (3) Keep (Bi,Sb)2S3@C at a temperature of 260 °C and an Ar gas pressure of 0.86 Mpa for 12 hours to obtain the target product a-(Bi,Sb)2S3@C material.

[0085] This material is a self-supporting material and does not require slurry coating and current collectors. Directly cut the a-(Bi,Sb)2S3@C material into 5*5 mm thin slices. Use potassium / lithium as the negative electrode sheet, glass fiber as the separator, and the electrolyte used is 4M KFSI or LiTFSI (the solvent is DME). Assemble a half-cell in a glove box filled with argon and perform a constant current charge-discharge test in the voltage range of 0.01 to 3.0 V.

[0086] Figure 2 The TEM image of the a-(Bi,Sb)2S3@C material prepared in this example is given, and it can be clearly seen that the material is amorphous nano BiSbS particles. Figure 3The charge-discharge curves of the a-(Bi,Sb)2S3@C material are presented, showing obvious conversion and alloying plateaus. The first reversible specific capacity of this material reaches 537 mAh / g. Figure 4 The cycling stability of the a-(Bi,Sb)2S3@C material is given. The reversible specific capacity is as high as 445 mAh / g after 100 cycles at a current density of 100 mA / g.

[0087] Comparative Example 1:

[0088] (1) Dissolve 0.5 mmol of bismuth nitrate and 1.5 mmol of antimony acetate in 5.5 mL of DMF solvent. Then add 0.25 g of PAN to prepare an electrospinning sol-gel solution. The electrospinning parameters are: 15 kV, 1 mL / h, and the distance between the needle and the receiver is 20 cm;

[0089] (2) Collect the electrospun fiber film material and heat it in a muffle furnace at a heating rate of 2 °C / min and hold it at 280 °C for 6 h. Subsequently, place it in a tubular furnace under an Ar / H2 mixed atmosphere and further carbonize it at a heating rate of 2 °C / min at 600 °C for 6 h to obtain (Bi,Sb)2S3@C. Sulfurize the carbon fiber-wrapped nanoalloy material to obtain the carbon fiber-wrapped nanoalloy sulfide material (Bi,Sb)2S3@C;

[0090] This material is a self-supporting material and does not require slurry coating and current collector. Directly cut the a-(Bi,Sb)2S3@C material into 5*5 mm thin slices. Use potassium / lithium as the negative electrode, glass fiber as the separator, and the electrolyte is 4 M KFSI or LiTFSI (the solvent is DME). Assemble a half-cell in a glove box filled with argon and perform constant current charge-discharge tests in the voltage range of 0.01 - 3.0 V.

[0091] Figure 5 The TEM images of the (Bi,Sb)2S3@C material prepared in this example are given, and it can be clearly seen that the material is crystalline nano (Bi,Sb)2S3@C particles. Figure 6 The charge-discharge curves of the (Bi,Sb)2S3@C material are presented, showing obvious conversion and alloying plateaus and the first reversible specific capacity of 556 mAh / g. Figure 7 The cycling stability performance of the (Bi,Sb)2S3@C material is given. Its capacity is only 244 mAh / g after 100 cycles at a current density of 100 mA / g.

[0092] The embodiments of the present application have been described above in conjunction with the accompanying drawings. However, the present application is not limited to the above specific embodiments. The above specific embodiments are merely illustrative rather than restrictive. Under the inspiration of the present application, those of ordinary skill in the art can also make many forms without departing from the purpose of the present application and the scope protected by the claims, and all of them belong to the protection scope of the present application.

Claims

1. A preparation method of an amorphous anode material for a battery, characterized in that, Including: Stir polyacrylonitrile and dimethylformamide under a first preset condition to obtain a sol-gel solution; Add bismuth salt and antimony salt into the sol-gel solution, and stir for a preset time to disperse them evenly to obtain a sol-gel solution containing metal ions; Perform electrospinning on the sol-gel solution containing metal ions under a second preset condition to obtain a film precursor material; Perform pre-oxidation treatment on the film precursor material in air to obtain a pretreated material; Perform carbonization and reduction treatment on the pretreated material under a third preset condition to obtain a carbonized material; Perform sulfidation treatment on the carbonized material to obtain a carbon fiber-wrapped nanoalloy material; Perform heating and pressurization treatment on the carbon fiber-wrapped nanoalloy material to obtain a carbon fiber-wrapped amorphous nanoalloy sulfide material.

2. The preparation method of the amorphous anode material for the battery according to claim 1, wherein The mass-volume ratio of the polyacrylonitrile to the dimethylformamide is 0.4 - 1.5 g: 10 mL; The mass ratio of the polyacrylonitrile to the total mass of the bismuth salt and the antimony salt is 0.1 - 5.

3. The preparation method of the amorphous anode material for the battery according to claim 1, characterized in that, The bismuth salt and the antimony salt are one or more combinations of chlorides, sulfates, nitrates, and acetates.

4. The preparation method of the amorphous anode material for a battery according to claim 1, characterized in that, The preset time is 4 - 48 h.

5. The preparation method of the amorphous anode material for a battery according to claim 1, characterized in that, The second preset condition includes: The flow rate of the sol-gel solution is 0.5 mL / h - 1.2 mL / h; The distance from the metal needle head for electrospinning to the metal plate is 8 - 30 cm.

6. The preparation method of the amorphous anode material for the battery according to claim 1, characterized in that, The temperature of the pre-oxidation treatment is 200 - 300 °C; The time of the pre-oxidation treatment is 6 h.

7. The preparation method of the amorphous anode material for the battery according to claim 1, wherein The third preset condition includes: Place the pretreated material in a mixed gas of Ar and H2; The time of carbonization and reduction treatment is 2 - 12 h.

8. The preparation method of the amorphous anode material for the battery according to claim 1, characterized in that, The conditions of the sulfidation treatment include: The ratio of the carbonized material to sulfur is 1: 3 - 20; The sulfidation temperature is 400 - 600 °C; The sulfidation time is 1 - 5 h.

9. An amorphous anode material for a battery, characterized in that, The amorphous anode material of the battery is prepared by using the preparation method of the amorphous anode material of the battery according to any one of claims 1 - 8.

10. A battery, characterized in that, The material of the battery anode is the amorphous anode material of the battery according to claim 9.

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