Preparation method of three-dimensional self-supporting power type carbon fluoride electrode material

Abstract

The invention belongs to the technical field of electrode materials, and particularly relates to a preparation method of a three-dimensional self-supporting power type carbon fluoride electrode material. According to the prepared three-dimensional self-supporting power type carbon fluoride electrode material, the transition metal oxides are uniformly distributed in the substrate nanofibers, the electron and ion conductivity of the material can be effectively improved through the synergistic effect of the transition metal oxides and the substrate nanofibers, and the rate capability of a battery is improved; according to the prepared three-dimensional self-supporting power type carbon fluoride electrode material, a large number of three-dimensional channels are distributed in the electrode material, electric quantity active sites are provided for reaction, migration of lithium ions in the electrode material is facilitated, and the rate performance of the electrode material is further improved; according to the prepared three-dimensional self-supporting power type carbon fluoride electrode material, the three-dimensional structure of the electrode material provides a space for lithium fluoride deposited on a positive electrode during discharging, the expansion effect of the positive electrode is relieved, and the problem of voltage lag of a carbon fluoride battery is solved.

Description

[0001] This invention belongs to the field of electrode material technology, specifically relating to a method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material. Background Art

[0002] Fluorinated carbon batteries have promising applications in instruments, medical devices, and weaponry due to their high theoretical specific energy, wide operating temperature range, low self-discharge rate, and long storage life.

[0003] However, the poor electronic conductivity of fluorinated carbon materials and the insulating properties of lithium fluoride products generated during discharge cause fluorinated carbon batteries to suffer from capacity decay and voltage hysteresis under high-rate discharge conditions, limiting their application in high-power applications. To improve the rate performance of fluorinated carbon batteries and alleviate the voltage hysteresis problem, researchers have explored various improvement methods.

[0004] Chinese patent CN 117334992A discloses a fluorinated carbon battery with a three-dimensional conductive network and its preparation method. This method utilizes carbon nanoparticles, highly oriented carbon nanotube arrays, and monolayer graphene to form a unique hybrid conductive network composed of zero-dimensional / one-dimensional / three-dimensional carbon materials in the fluorinated carbon electrode, thereby weakening the surface polarization effect of the fluorinated carbon active material. While this preparation method improves the electrode's electronic conductivity to some extent, as the discharge depth increases, the electrode still suffers from the problem of lithium fluoride encapsulating and blocking the lithium-ion insertion channels, preventing sustained high-rate discharge.

[0005] Chinese invention patent CN 115763755 A discloses a method for synthesizing CFx / Mn5O8 composite cathode materials. This method uses CFx and a manganese source as raw materials to synthesize a precursor material with rod-shaped MnOOH grown on the CFx surface via hydrothermal treatment. Subsequently, the precursor is calcined in an oxygen atmosphere to obtain the CFx / Mn5O8 composite material. The rod-shaped Mn5O8 forms a network structure on the CFx surface, effectively improving electron conduction and ion transport processes. This preparation method improves the discharge rate by combining CFx and Mn5O8 materials. However, the uniformity of Mn5O8 distribution in the composite material is poor, and there is a problem where active sites are encapsulated by lithium fluoride as the discharge depth increases, affecting electrical performance. Summary of the Invention

[0006] To address the issues of insufficient rate performance and voltage hysteresis in fluorinated carbon batteries, the present invention aims to provide a method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material.

[0007] Specifically, this is achieved through the following technical solutions:

[0008] A method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material includes the following steps:

[0009] (1) Preparation of electrospinning solution: Add electrospinning agent to solvent, stir at constant temperature to prepare transparent solution; then add acetate to transparent solution, stir at constant temperature to obtain electrospinning solution;

[0010] (2) Preparation of nanofiber membrane: The electrospinning solution obtained in (1) is added to a syringe for electrospinning, and aluminum foil is used to receive the spinning to obtain a nanofiber membrane.

[0011] (3) Preparation of composite carbon fiber membrane: The nanofiber membrane obtained in (2) is placed in a muffle furnace and heated to react under a protective gas atmosphere to obtain a composite carbon fiber membrane.

[0012] (4) Preparation of three-dimensional self-supporting power type fluorinated carbon electrode material: The composite carbon fiber membrane prepared in (3) is placed in the fluorination equipment and fluorine-containing gas is introduced. The fluorine-containing gas reacts with the composite carbon fiber membrane. After the reaction is completed, the material is taken out after the temperature of the fluorination equipment naturally drops to room temperature. The three-dimensional self-supporting power type fluorinated carbon electrode material is obtained.

[0013] Further, in step (1), the electrospinning agent is any one of polyvinyl alcohol, polyvinylpyrrolidone, polymethyl methacrylate, and polyacrylonitrile.

[0014] In step (1), the solvent is any one of deionized water, ethanol, acetone, N,N-dimethylformamide, and acetic acid.

[0015] In step (1), the mass fraction of the transparent solution is 9% to 15%.

[0016] In step (1), when preparing the transparent solution, the stirring temperature is 20°C to 30°C and the stirring time is 3 to 6 hours; when preparing the electrospinning solution, the stirring temperature is 20°C to 30°C and the stirring time is 1.5 to 3.5 hours.

[0017] In step (1), the acetate is any one of iron acetate, cobalt acetate, manganese acetate, and copper acetate.

[0018] In step (1), the acetate is used in a mass ratio of 1:0.6 to 1:3.2 with the electrospinning agent.

[0019] In step (2), the electrospinning voltage is 16kV to 24kV.

[0020] In step (2), the receiving distance of electrospinning is 12 to 25 cm, and the syringe advance speed is 0.12 mL / h to 0.48 mL / h.

[0021] In step (3), the protective gas is any one of nitrogen, argon, or helium.

[0022] In step (3), the heating reaction has a temperature rise rate of 1℃ / min to 3℃ / min, a reaction temperature of 450℃ to 750℃, and a reaction time of 1.5h to 4.5h.

[0023] In step (4), the fluorine-containing gas is a mixture of fluorine and inert gas, wherein the fluorine content is 3 wt.% to 8 wt.% and the inert gas content is 92 wt.% to 97 wt.%.

[0024] In step (4), the pressure during the reaction is 120 kPa to 220 kPa, the temperature is 280°C to 650°C, and the reaction time is 10 h to 14 h.

[0025] Beneficial effects

[0026] The method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material protected by this invention has the following beneficial effects:

[0027] 1. The three-dimensional self-supporting power-type fluorinated carbon electrode material prepared by this invention has a transition metal oxide uniformly distributed in the substrate nanofibers. The synergistic effect of the two can effectively improve the electronic and ionic conductivity of the material and improve the rate performance of the battery.

[0028] 2. The three-dimensional self-supporting power-type fluorinated carbon electrode material prepared by the present invention has a large number of three-dimensional channels distributed inside the electrode material, which provides charge-active sites for the reaction and facilitates the migration of lithium ions inside the electrode material, thereby further improving its rate performance.

[0029] 3. The three-dimensional self-supporting power-type fluorinated carbon electrode material prepared by this invention provides space for lithium fluoride deposited on the positive electrode during discharge, alleviates the positive electrode expansion effect, and solves the problem of voltage hysteresis in fluorinated carbon batteries. Attached Figure Description

[0030] Figure 1 This is a scanning electron microscope image of the three-dimensional self-supporting power-type fluorinated carbon electrode material in Example 3; Figure 2 The battery discharge curves for the three-dimensional self-supporting power-type fluorinated carbon electrode material and ordinary fluorinated carbon material in Example 3 are shown. Detailed Implementation

[0031] Example 1

[0032] A method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material, comprising the following steps:

[0033] (1) Add polyvinyl alcohol to deionized water and stir at a constant temperature for 3 hours to prepare a transparent solution with a mass fraction of 9%; add ferric acetate and polyvinyl alcohol to the transparent solution at a mass ratio of 1:0.6 and continue stirring at a constant temperature for 1.5 hours to obtain the electrospinning solution;

[0034] (2) Electrospinning solution was added to a syringe for electrospinning. The spinning voltage was 16kV. Aluminum foil was used to receive the spinning solution at a distance of 12cm. The syringe was pushed at a speed of 0.12mL / h to obtain a nanofiber membrane.

[0035] (3) The nanofiber membrane is placed in a muffle furnace and heated to 450°C to 750°C at a temperature rise rate of 1°C / min to 3°C / min under a protective gas atmosphere. After reaching the set temperature, it is calcined at a constant temperature for 1.5h to 4.5h to obtain a composite carbonized fiber membrane.

[0036] (4) The prepared composite carbonized fiber membrane is placed in a fluorination device and an inert gas containing 3 wt.% fluorine is introduced. The fluorine-containing inert gas reacts with the composite carbonized fiber membrane containing iron oxide. The reaction is carried out for 10 hours under the conditions of maintaining a pressure of 120 kPa and a temperature of 280°C. After the temperature of the fluorination device naturally drops to room temperature, the material is taken out to obtain a three-dimensional self-supporting power type fluorinated carbon electrode material.

[0037] Example 2

[0038] A method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material, the steps are as follows: (1) Add polyvinylpyrrolidone to ethanol, stir at constant temperature for 4 hours, and prepare a transparent solution with a mass fraction of 9.8%; add cobalt acetate and polyvinylpyrrolidone to the transparent solution at a mass ratio of 1:1.1, stir at constant temperature for 2 hours, and obtain an electrospinning solution;

[0039] (2) Add the electrospinning solution to the syringe for electrospinning. The spinning voltage is 18kV. Aluminum foil is used to receive the spinning solution at a distance of 15cm. The syringe advance speed is 0.20mL / h to obtain a nanofiber membrane.

[0040] (3) The nanofiber membrane was placed in a muffle furnace and heated to 550°C at a rate of 2°C / min under an argon atmosphere. After reaching the set temperature, it was calcined at a constant temperature for 2.5 hours to obtain a carbonized fiber membrane with cobalt oxide composite.

[0041] (4) The carbon fiber membrane with cobalt oxide composite was placed in a fluorination device and an inert gas containing 5 wt.% fluorine was introduced. The fluorine-containing inert gas reacted with the carbon fiber membrane with cobalt oxide composite. The reaction was carried out for 12 hours under the conditions of maintaining a pressure of 160 kPa and a temperature of 380 °C. After the temperature of the fluorination device naturally dropped to room temperature, the material was taken out to obtain a three-dimensional self-supporting power type fluorinated carbon electrode material.

[0042] Example 3

[0043] A method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material, the steps are as follows: (1) Add polymethyl methacrylate to acetone, stir at constant temperature for 5 hours to prepare a transparent solution with a mass fraction of 12%; add manganese acetate and polyacrylonitrile to the transparent solution at a mass ratio of 1:2.5, stir at constant temperature for 3 hours to obtain an electrospinning solution;

[0044] (2) Add the electrospinning solution to the syringe for electrospinning. The spinning voltage is 20kV. Aluminum foil is used to receive the spinning solution at a distance of 20cm. The syringe advance speed is 0.30mL / h to obtain a nanofiber membrane.

[0045] (3) The nanofiber membrane was placed in a muffle furnace and heated to 650°C at a rate of 2.5°C / min under a helium atmosphere. After reaching the set temperature, it was calcined at a constant temperature for 3.5 hours to obtain a carbonized fiber membrane with manganese oxide.

[0046] (4) The carbon fiber membrane with manganese oxide composite was placed in a fluorination device and an inert gas containing 6 wt.% fluorine was introduced. The fluorine-containing inert gas reacted with the carbon fiber membrane with manganese oxide composite. The reaction was carried out for 13 hours under the conditions of maintaining a pressure of 180 kPa and a temperature of 480℃. After the temperature of the fluorination device naturally dropped to room temperature, the material was taken out to obtain a three-dimensional self-supporting power type fluorinated carbon electrode material.

[0047] Example 4

[0048] A method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material, the steps are as follows: (1) Add polyacrylonitrile to acetic acid, stir at constant temperature for 6 hours, and prepare a transparent solution with a mass fraction of 15%; add copper acetate and polyacrylonitrile to the transparent solution at a mass ratio of 1:3.2, stir at constant temperature for 3.5 hours to obtain an electrospinning solution;

[0049] (2) Electrospinning solution was added to a syringe for electrospinning. The spinning voltage was 24kV. Aluminum foil was used to receive the spinning solution at a distance of 25cm. The syringe was pushed at a speed of 0.48mL / h to obtain a nanofiber membrane.

[0050] (3) The nanofiber membrane was placed in a muffle furnace and heated to 750°C at a rate of 3°C / min under an argon atmosphere. After reaching the set temperature, it was calcined at a constant temperature for 4.5 hours to obtain a carbonized fiber membrane with copper oxide.

[0051] (4) The carbon fiber membrane with manganese oxide composite was placed in a fluorination device and an inert gas containing 8 wt.% fluorine was introduced. The fluorine-containing inert gas reacted with the carbon fiber membrane with manganese oxide composite. The reaction was carried out for 14 hours under the conditions of maintaining a pressure of 220 kPa and a temperature of 650℃. After the temperature of the fluorination device naturally dropped to room temperature, the material was taken out to obtain a three-dimensional self-supporting power type fluorinated carbon electrode material.

[0052] Example 5

[0053] A method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material, the steps are as follows: (1) Add polyethanol to ethanol, stir at constant temperature for 4h, and prepare a transparent solution with a mass fraction of 11%; add cobalt acetate and polyethanol to the transparent solution at a mass ratio of 1:1.2, stir at constant temperature for 2.5h, and obtain an electrospinning solution;

[0054] (2) Electrospinning solution was added to a syringe for electrospinning. The spinning voltage was 22kV. Aluminum foil was used to receive the spinning solution at a distance of 22cm. The syringe was pushed at a speed of 0.28mL / h to obtain a nanofiber membrane.

[0055] (3) The nanofiber membrane was placed in a muffle furnace and heated to 550°C at a rate of 1.3°C / min under a helium atmosphere. After reaching the set temperature, it was calcined at a constant temperature for 3.5 hours to obtain a carbonized fiber membrane with cobalt oxide composite.

[0056] (4) The carbon fiber membrane with cobalt oxide composite was placed in a fluorination device and an inert gas containing 4.5 wt.% fluorine was introduced. The fluorine-containing inert gas reacted with the carbon fiber membrane with cobalt oxide composite. The reaction was carried out for 12 hours under the conditions of maintaining a pressure of 210 kPa and a temperature of 550 °C. After the temperature of the fluorination device naturally dropped to room temperature, the material was taken out to obtain a three-dimensional self-supporting power type fluorinated carbon electrode material.

[0057] Example 6

[0058] A method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material, the steps are as follows: (1) Add polyvinylpyrrolidone to deionized water, stir at constant temperature for 4.5h, and prepare a transparent solution with a mass fraction of 12%; add ferric acetate and polyvinylpyrrolidone to the transparent solution at a mass ratio of 1:2.2, stir at constant temperature for 3.5h, and obtain an electrospinning solution;

[0059] (2) Electrospinning solution was added to a syringe for electrospinning. The spinning voltage was 23kV. Aluminum foil was used to receive the spinning solution at a distance of 24cm. The syringe was pushed at a speed of 0.38mL / h to obtain a nanofiber membrane.

[0060] (3) The nanofiber membrane was placed in a muffle furnace and heated to 450°C at a rate of 2.3°C / min under an argon atmosphere. After reaching the set temperature, it was calcined at a constant temperature for 3.8 hours to obtain a carbonized fiber membrane with iron oxide composite.

[0061] (4) The carbonized fiber membrane with iron oxide composite was placed in a fluorination device and an inert gas containing 5.5 wt.% fluorine was introduced. The fluorine-containing inert gas reacted with the carbonized fiber membrane with iron oxide composite. The reaction was carried out for 13 hours under the conditions of maintaining a pressure of 180 kPa and a temperature of 480 °C. After the temperature of the fluorination device naturally dropped to room temperature, the material was taken out to obtain a three-dimensional self-supporting power type fluorinated carbon electrode material.

[0062] Example 7

[0063] A method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material, comprising the following steps: (1) adding polymethyl methacrylate to N,N-dimethylformamide and stirring at a constant temperature for 5 hours to prepare a transparent solution with a mass fraction of 15%; adding copper acetate and polymethyl methacrylate to the transparent solution at a mass ratio of 1:2.5 and stirring at a constant temperature for 3.5 hours to obtain an electrospinning solution;

[0064] (2) Electrospinning solution was added to a syringe for electrospinning. The spinning voltage was 24kV. Aluminum foil was used to receive the spinning solution at a distance of 25cm. The syringe was pushed at a speed of 0.48mL / h to obtain a nanofiber membrane.

[0065] (3) The nanofiber membrane was placed in a muffle furnace and heated to 550°C at a rate of 2.5°C / min under a nitrogen atmosphere. After reaching the set temperature, it was calcined at a constant temperature for 4 hours to obtain a carbonized fiber membrane with copper oxide.

[0066] (4) The carbon fiber membrane with copper oxide composite was placed in a fluorination device and an inert gas containing 6.5 wt.% fluorine was introduced. The fluorine-containing inert gas reacted with the carbon fiber membrane with copper oxide composite. The reaction was carried out for 12 hours under the conditions of maintaining a pressure of 190 kPa and a temperature of 500℃. After the temperature of the fluorination device naturally dropped to room temperature, the material was taken out to obtain a three-dimensional self-supporting power type fluorinated carbon electrode material.

[0067] Example 8

[0068] A method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material, the steps are as follows: (1) Add polyacrylonitrile to acetone, stir at constant temperature for 4 hours, and prepare a transparent solution with a mass fraction of 11%; add manganese acetate and polyacrylonitrile to the transparent solution at a mass ratio of 1:3, stir at constant temperature for 2.5 hours, and obtain an electrospinning solution;

[0069] (2) Add the electrospinning solution to the syringe for electrospinning. The spinning voltage is 20kV. Aluminum foil is used to receive the spinning solution at a distance of 21cm. The syringe advance speed is 0.3mL / h to obtain a nanofiber membrane.

[0070] (3) The nanofiber membrane was placed in a muffle furnace and heated to 650°C at a rate of 2.7°C / min under a helium atmosphere. After reaching the set temperature, it was calcined at a constant temperature for 4 hours to obtain a carbonized fiber membrane with manganese oxide.

[0071] (4) The carbon fiber membrane with manganese oxide composite was placed in a fluorination device and an inert gas containing 7.5 wt.% fluorine was introduced. The fluorine-containing inert gas reacted with the carbon fiber membrane with manganese oxide composite. The reaction was carried out for 13 hours under the conditions of maintaining a pressure of 210 kPa and a temperature of 600℃. After the temperature of the fluorination device naturally dropped to room temperature, the material was taken out to obtain a three-dimensional self-supporting power type fluorinated carbon electrode material.

[0072] Example 9

[0073] A method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material, the steps are as follows: (1) Polyvinylpyrrolidone is added to acetic acid and stirred at a constant temperature for 3.8 h to prepare a transparent solution with a mass fraction of 13%; Manganese acetate and polyacrylonitrile are added to the transparent solution at a mass ratio of 1:2.8 and stirred at a constant temperature for 3 h to obtain an electrospinning solution;

[0074] (2) Electrospinning solution was added to a syringe for electrospinning. The spinning voltage was 19kV. Aluminum foil was used to receive the spinning solution at a distance of 22cm. The syringe was pushed at a speed of 0.35mL / h to obtain a nanofiber membrane.

[0075] (3) The nanofiber membrane was placed in a muffle furnace and heated to 660°C at a rate of 2.5°C / min under an argon atmosphere. After reaching the set temperature, it was calcined at a constant temperature for 3.5 hours to obtain a carbonized fiber membrane with manganese oxide composite.

[0076] (4) The carbon fiber membrane with manganese oxide composite was placed in a fluorination device and an inert gas containing 5.5 wt.% fluorine was introduced. The fluorine-containing inert gas reacted with the carbon fiber membrane with manganese oxide composite. The reaction was carried out for 12 hours under the conditions of maintaining a pressure of 160 kPa and a temperature of 350 °C. After the temperature of the fluorination device naturally dropped to room temperature, the material was taken out to obtain a three-dimensional self-supporting power type fluorinated carbon electrode material.

[0077] Example 10

[0078] A method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material, the steps are as follows: (1) Add polyvinyl alcohol to acetone, stir at constant temperature for 4 hours, and prepare a transparent solution with a mass fraction of 13.5%; add ferric acetate and polyvinyl alcohol to the transparent solution at a mass ratio of 1:1.5, stir at constant temperature for 3 hours, and obtain an electrospinning solution;

[0079] (2) Electrospinning solution was added to a syringe for electrospinning. The spinning voltage was 18kV. Aluminum foil was used to receive the spinning solution at a distance of 23cm. The syringe was pushed at a speed of 0.42mL / h to obtain a nanofiber membrane.

[0080] (3) The nanofiber membrane was placed in a muffle furnace and heated to 500°C at a rate of 1.5°C / min under an argon atmosphere. After reaching the set temperature, it was calcined at a constant temperature for 2.5 hours to obtain a carbonized fiber membrane with iron oxide composite.

[0081] (4) The carbonized fiber membrane with iron oxide composite was placed in a fluorination device and an inert gas containing 7.5 wt.% fluorine was introduced. The fluorine-containing inert gas reacted with the carbonized fiber membrane with iron oxide composite. The reaction was carried out for 13 hours under the conditions of maintaining a pressure of 180 kPa and a temperature of 450 °C. After the temperature of the fluorination device naturally dropped to room temperature, the material was taken out to obtain a three-dimensional self-supporting power type fluorinated carbon electrode material.

[0082] Example 11

[0083] A method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material, the steps are as follows: (1) Add polyacrylonitrile to deionized water, stir at constant temperature for 3 hours, and prepare a transparent solution with a mass fraction of 9%; add cobalt acetate and polyacrylonitrile to the transparent solution at a mass ratio of 1:3, stir at constant temperature for 3.5 hours, and obtain an electrospinning solution;

[0084] (2) Electrospinning solution was added to a syringe for electrospinning. The spinning voltage was 24kV. Aluminum foil was used to receive the spinning solution at a distance of 25cm. The syringe was pushed at a speed of 0.48mL / h to obtain a nanofiber membrane.

[0085] (3) The nanofiber membrane was placed in a muffle furnace and heated to 750°C at a rate of 3°C / min under an argon atmosphere. After reaching the set temperature, it was calcined at a constant temperature for 4.5 hours to obtain a carbonized fiber membrane with cobalt oxide composite.

[0086] (4) The carbon fiber membrane with cobalt oxide composite was placed in a fluorination device and an inert gas containing 8 wt.% fluorine was introduced. The fluorine-containing inert gas reacted with the carbon fiber membrane with cobalt oxide composite. The reaction was carried out for 14 hours under the conditions of maintaining a pressure of 220 kPa and a temperature of 650 °C. After the temperature of the fluorination device naturally dropped to room temperature, the material was taken out to obtain a three-dimensional self-supporting power type fluorinated carbon electrode material.

[0087] Example 12

[0088] A method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material, the steps are as follows: (1) Add polyvinylpyrrolidone to acetic acid, stir at constant temperature for 5 hours, and prepare a transparent solution with a mass fraction of 14%; add manganese acetate and polyvinylpyrrolidone to the transparent solution at a mass ratio of 1:3, stir at constant temperature for 2.5 hours, and obtain an electrospinning solution;

[0089] (2) Add the electrospinning solution to the syringe for electrospinning. The spinning voltage is 23kV. Aluminum foil is used to receive the spinning solution at a distance of 25cm. The syringe advance speed is 0.28mL / h to obtain a nanofiber membrane.

[0090] (3) The nanofiber membrane was placed in a muffle furnace and heated to 550°C at a rate of 1°C / min under an argon atmosphere. After reaching the set temperature, it was calcined at a constant temperature for 4 hours to obtain a carbonized fiber membrane with manganese oxide.

[0091] (4) The carbon fiber membrane with manganese oxide composite was placed in a fluorination device and an inert gas containing 4.5 wt.% fluorine was introduced. The fluorine-containing inert gas reacted with the carbon fiber membrane with manganese oxide composite. The reaction was carried out for 12 hours under the conditions of maintaining a pressure of 200 kPa and a temperature of 450℃. After the temperature of the fluorination device naturally dropped to room temperature, the material was taken out to obtain a three-dimensional self-supporting power type fluorinated carbon electrode material.

[0092] Scanning electron microscope (SEM) images of the three-dimensional self-supporting power-type fluorinated carbon electrode material in Example 3 were collected, and the results are as follows: Figure 1 As shown, by Figure 1 It can be seen that the prepared fluorinated carbon electrode material has a three-dimensional porous structure with uniform fiber diameter, which allows for better contact with the electrolyte, shortens the lithium ion migration distance, and improves the rate performance of the material. The manganese oxide material has good rate performance, and its uniform distribution in the fiber, together with the three-dimensional structure, further improves the rate performance of the battery material.

[0093] The discharge curves of batteries prepared from the three-dimensional self-supporting power-type fluorinated carbon electrode material in Example 3 and those prepared from ordinary fluorinated carbon materials were measured, and the results are as follows: Figure 2 As shown, by Figure 2 It can be seen that when batteries are made using fluorinated carbon electrode materials prepared by this method and conventional fluorinated carbon electrode materials, the electrode materials prepared by this method have better power performance than conventional electrode materials when discharged at the same rate.

[0094] Based on the above embodiments, the present invention provides a method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material, which solves the problems of insufficient rate performance and voltage hysteresis of fluorinated carbon batteries.

[0095] While preferred embodiments of the present invention have been disclosed above, they are not intended to limit the invention. Any researcher in the art can modify and alter the research scheme of the present invention using the design parameters and content of the disclosed embodiments without departing from the spirit and scope of the invention. Therefore, any simple modifications, parameter changes, and alterations made to the above embodiments based on the research essence of the present invention, without departing from the content of the present invention, fall within the protection scope of the present invention.

Claims

1. A method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material, characterized in that, The preparation method includes the following four steps: (1) Preparation of electrospinning solution: Add electrospinning agent to solvent, stir at constant temperature to prepare transparent solution; then add acetate to transparent solution, stir at constant temperature to obtain electrospinning solution; (2) Preparation of nanofiber membrane: The electrospinning solution obtained in (1) is added to a syringe for electrospinning, and aluminum foil is used to receive the spinning to obtain a nanofiber membrane. (3) Preparation of composite carbonized fiber membrane: The nanofiber membrane obtained in (2) is placed in a muffle furnace and heated and carbonized under a protective gas atmosphere to obtain a composite carbonized fiber membrane. (4) Preparation of three-dimensional self-supporting power type fluorinated carbon electrode material: The composite carbon fiber membrane prepared in (3) is placed in the fluorination equipment and fluorine-containing gas is introduced. The fluorine-containing gas reacts with the composite carbon fiber membrane. After the reaction is completed, the material is taken out after the temperature of the fluorination equipment naturally drops to room temperature. The three-dimensional self-supporting power type fluorinated carbon electrode material is obtained.

2. A method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material, characterized in that, The electrospinning agent mentioned in (1) is any one of polyvinyl alcohol, polyvinylpyrrolidone, polymethyl methacrylate, and polyacrylonitrile; the solvent mentioned in (1) is any one of deionized water, ethanol, acetone, N,N-dimethylformamide, and acetic acid.

3. A method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material, characterized in that, (1) The mass fraction of the transparent solution is 9% to 15%; the stirring temperature is 20°C to 30°C and the stirring time is 3 to 6 hours when preparing the transparent solution; the stirring temperature is 20°C to 30°C and the stirring time is 1.5 to 3.5 hours when preparing the electrospinning solution.

4. A method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material, characterized in that, (1) The acetate salt mentioned is any one of iron acetate, cobalt acetate, manganese acetate, and copper acetate; the mass ratio of the acetate salt to the electrospinning agent is 1:0.6 to 1:3.

2.

5. A method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material, characterized in that, (2) describes an electrospinning voltage of 16kV to 24kV.

6. A method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material, characterized in that, (2) The receiving distance for electrospinning is 12 to 25 cm, and the syringe advance speed is 0.12 mL / h to 0.48 mL / h.

7. A method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material, characterized in that, (3) The protective gas mentioned is any one of nitrogen, argon, and helium.

8. A method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material, characterized in that, (3) The heating carbonization temperature rise rate is 1℃ / min to 3℃ / min, the reaction temperature is 450℃ to 750℃, and the reaction time is 1.5h to 4.5h.

9. A method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material, characterized in that, (4) The fluorine-containing gas mentioned is a mixture of fluorine and inert gas, wherein the fluorine content is 3 wt.% to 8 wt.% and the inert gas content is 92 wt.% to 97 wt.%.

10. A method for preparing a three-dimensional self-supporting power-type fluorinated carbon electrode material, characterized in that, (4) The pressure during the reaction is 120 kPa to 220 kPa, the temperature is 280°C to 650°C, and the reaction time is 10 h to 14 h.

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