Preparation method of fluorinated graphene film and battery

Abstract

The embodiment of the invention provides a preparation method of a fluorinated graphene membrane and a battery, fluorinated graphene and carbon nanotubes are mixed and infiltrated in a mixed solution of absolute ethyl alcohol and deionized water, a reductive defluorination mixed solution and a polyvinyl alcohol aqueous solution are added, vacuum filtration is performed after ultrasonic treatment, a filter membrane is stripped after drying, and the fluorinated graphene membrane is obtained; wherein the fluorine content of the fluorinated graphene film is 33%-45%, the doping amount of metal particles is 7.45%-16.7% by weight, and the surface loading amount of an active substance is 3.32 mg / cm < 2 >-5.24 mg / cm < 2 >; the method is a one-step continuous process, the fluorine content of fluorinated graphene is reduced through reduction and defluorination, reduction of conductive metal particles is carried out, and a stable self-supporting three-dimensional conductive network structure is constructed by utilizing the synergistic effect of hydrogen bonds formed among polyvinyl alcohol hydroxyl groups; according to the preparation method, the hydrophilicity of the fluorinated graphene film is improved, the surface loading capacity of the low-tap-density fluorinated graphene is improved, meanwhile, the conductivity of the fluorinated graphene film is improved, polarization in the discharging process is relieved, and application of the lithium / carbon fluoride battery in a high-power electronic device is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of preparation of battery electrodes, and in particular to a preparation method of a fluorinated graphene film and a battery. Background Art

[0002] Lithium / carbon fluoride batteries have the advantages of long life, low self-discharge, wide operating temperature, and environmental friendliness, and have broad application prospects in portable electronic devices, implantable medical devices, and equipment power supplies. Graphene fluoride with a low-dimensional nanostructure can improve its conductivity to a certain extent compared to conventional carbon fluoride materials, but when the surface loading of active substances is increased, the electrodes prepared by the traditional slurry coating method using lightweight graphene fluoride positive electrode materials are prone to deformation or damage due to the low tap density characteristics of the material, making it difficult to prepare intact electrodes.

[0003] Therefore, the surface loading of active materials can be increased by preparing fluorinated graphene membranes. However, as a product of fluorination of graphene edges, fluorinated graphene rapidly decreases from a conductor to an insulator with the introduction of fluorine atoms and the increase of the degree of fluorination. Therefore, conventionally prepared fluorinated graphene membranes have certain hydrophobicity and insulation properties and are difficult to be used in lithium / carbon fluoride battery systems. Summary of the invention

[0004] In view of this, the present invention provides a method for preparing a fluorinated graphene membrane and a battery, which can reduce the fluorine content, construct a metal conductive layer and a self-supporting three-dimensional conductive network structure in one step, improve the hydrophilicity of the fluorinated graphene membrane, and increase the surface loading and conductivity of its active substances. The fluorinated graphene membrane prepared by this method not only has multiple effects, but also helps to improve the electrochemical performance of lithium / carbon fluoride batteries.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] The fluorinated graphene and carbon nanotubes are mixed and immersed in a mixed solution of anhydrous ethanol and deionized water, and then a reduction and defluorination mixed solution is added to defluorinate the fluorinated graphene and reduce the conductive metal particles. The reduction and defluorination mixed solution is composed of a metal salt solution and a reducing agent;

[0007] A polyvinyl alcohol aqueous solution having hydroxyl groups and hydrogen bonds between the groups is added as a binder, and the aqueous solution is ultrasonically dispersed and vacuum filtered. After drying, the filter membrane is peeled off to obtain a fluorinated graphene membrane; wherein the fluorine content of the fluorinated graphene membrane is 33-45%, the metal particle doping amount is 7.45-16.7wt%, and the active material surface loading is 3.32-5.24mg / cm 2 .

[0008] Wherein, the method further comprises:

[0009] (1) immersing the fluorinated graphene and the carbon nanotubes in an anhydrous ethanol solution, stirring for 10 minutes and then ultrasonicating for 30 minutes, washing with alcohol to remove impurities, and then immersing in deionized water and anhydrous ethanol to form a first mixed solution;

[0010] (2) adding the mixed solution I into the sensitizing solution at a volume ratio of 1:9 for 1 h, washing to remove impurities and soaking in deionized water and anhydrous ethanol to form a second mixed solution;

[0011] (3) The second mixed solution is added to 90 mL of the reduction defluorination mixed solution in one step to react for 10 to 40 minutes, wherein the volume ratio of the metal salt solution to the reducing agent in the reduction defluorination mixed solution is 3:1; at the end of the time, 1 mL of polyvinyl alcohol aqueous solution is added dropwise to the solution, and after ultrasonication for 10 minutes, vacuum filtration is performed, and deionized water and anhydrous ethanol are repeatedly alternately washed for 3 times. The polyvinyl alcohol aqueous solution is prepared by dissolving polyvinyl alcohol powder in deionized water at 95°C;

[0012] (4) drying the obtained film-formed sample, peeling off the filter membrane, and obtaining a fluorinated graphene membrane;

[0013] (5) The fluorinated graphene film was cut into discs with a diameter of 12 mm and directly used as electrodes. Metal lithium was used as a counter electrode to assemble a lithium / carbon fluoride battery.

[0014] Wherein, the tap density of the fluorinated graphene is 0.04-0.05 g / cm 3 , the fluorine content is 50-60%.

[0015] The carbon nanotubes include at least one of multi-walled carbon nanotubes, single-walled carbon nanotubes, carbon nanowires, carbon nanotube bundles, and serpentine carbon nanotubes.

[0016] The mass percentage of the fluorinated graphene to the carbon nanotubes is 1-5:1, and the concentration of the first mixed solution is 5-10 mg / mL.

[0017] The sensitizing solution formula is that solid stannous chloride and hydrochloric acid solution are dissolved in deionized water and anhydrous ethanol solution with a volume ratio of 1:1. The concentration of stannous chloride in the mixed solution II is 20 g / L, and the concentration of hydrochloric acid is 6 mL / L.

[0018] Wherein, the reducing agent comprises at least one of a combination of glucose and sodium citrate, hydrazine, formaldehyde, and dimethylamino borane.

[0019] Wherein, the metal salt includes at least one of nitrate, chloride and sulfate, and the concentration is 100-300 mmol / L; the conductive metal particle is Ag.

[0020] Among them, the molecular weight of polyvinyl alcohol ranges from 120,000 to 150,000.

[0021] Wherein, the filter membrane includes at least one of a polytetrafluoroethylene membrane, a polyamide membrane, and a glass fiber membrane; the drying method is vacuum drying, and the drying time is 8 hours.

[0022] The present invention provides a method for preparing a fluorinated graphene membrane and a battery, the method comprising: mixing fluorinated graphene and carbon nanotubes and soaking them in a mixed solution of anhydrous ethanol and deionized water, adding a reduction defluorination mixed solution and a polyvinyl alcohol aqueous solution, performing vacuum filtration after ultrasonic treatment, and peeling off the filter membrane after drying to obtain a fluorinated graphene membrane. The fluorine content of the fluorinated graphene membrane is 33-45%, the metal particle doping amount is 7.45-16.7wt%, and the active material surface loading is 3.32-5.24mg / cm 2 , the maximum discharge rate of the battery reaches 8C. The fluorine content of fluorinated graphene is reduced by reduction and defluorination, the hydrophilicity of fluorinated graphene is improved, and the construction of the metal conductive layer of the reduced metal particles can improve the conductivity; and polyvinyl alcohol with rich hydroxyl groups and hydrogen bonds between groups is used as a binder to bond fluorinated graphene with metal particles and carbon nanotubes to each other, construct a stable self-supporting three-dimensional conductive network structure, further improve the electrode conductivity and increase the surface loading of active materials, reduce the voltage hysteresis effect, and realize the application of lithium / fluorinated carbon batteries in high-power electronic devices.

[0023] The present invention has the following beneficial effects:

[0024] (1) Compared with conventional hydrophobic insulating fluorinated graphene membranes, the present invention achieves the reduction of fluorine content and the reduction of conductive metal particles in one step through a controllable reduction defluorination method, thereby improving the hydrophilicity and conductivity of the fluorinated graphene membrane;

[0025] (2) The present invention makes full use of zero-dimensional metal particles and one-dimensional carbon nanotubes with high electrical conductivity, and bonds them to two-dimensional fluorinated graphene through hydrogen bonds formed between hydroxyl groups in polyvinyl alcohol, thereby constructing a stable self-supporting three-dimensional conductive network structure, further improving the conductivity of the fluorinated graphene film, reducing polarization during discharge, and improving the rate performance of the battery;

[0026] (3) Compared with the traditional slurry coating method, the fluorinated graphene film prepared by the method of the present invention not only does not require a current collector but can be directly used as a battery electrode. While ensuring good electrochemical properties, it can also increase the active material surface loading of lightweight fluorinated graphene in the electrode, effectively solving the problem that the fluorinated graphene with low tap density characteristics cannot increase the active material surface loading in the battery electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The actual object and bending diagram of the fluorinated graphene film provided in Example 1 of the present invention;

[0028] Figure 2 This is a scanning electron microscope image of the fluorinated graphene film provided in Example 1 of the present invention;

[0029] Figure 3 A water contact angle diagram of the fluorinated graphene film provided in Example 1 of the present invention;

[0030] Figure 4 Infrared spectra of the fluorinated graphene film provided in Example 1 of the present invention and Comparative Example 3;

[0031] Figure 5 This is an 8C rate discharge diagram of a lithium / carbon fluoride battery using a fluorinated graphene film as an electrode provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] Embodiment 1

[0034] In this embodiment, the tap density is 0.04-0.05 g / cm 3 , fluorinated graphene with a fluorine content of 55% was used as a raw material to prepare a fluorine content of 36%, a metal particle doping amount of 12.04wt%, and an active material surface loading of 5.09mg / cm 2 The maximum discharge rate of the battery of the fluorinated graphene film is 8C. The effect of the preparation method provided in this embodiment on the fluorine content, metal particle content, active material surface loading, and battery rate in the fluorinated graphene film is verified through specific experiments, as follows:

[0035] (1) immersing fluorinated graphene and carbon nanotubes in an anhydrous ethanol solution at a mass ratio of 4:1, stirring for 10 minutes and then ultrasonicating for 30 minutes, washing with alcohol to remove impurities, and immersing in equal volumes of deionized water and anhydrous ethanol in a ratio of 1:1, wherein the concentration of the first mixed solution is 10 mg / mL;

[0036] (2) adding the first mixed solution to the sensitizing solution at a volume ratio of 1:9 for 1 h, washing to remove impurities and soaking in deionized water and anhydrous ethanol solution, the concentration of the second mixed solution is 10 mg / mL;

[0037] (3) Prepare a reduction defluorination mixed solution. Preparation of the reduction solution: Dissolve 7.128 g of glucose solid and 1.912 g of trisodium citrate dihydrate in 30 mL of deionized water. Preparation of the metal silver salt solution: Dissolve 3.06 g of silver nitrate in 90 mL of deionized water, stir until the silver nitrate solution forms a colorless solution, then add 2 mg of potassium hydroxide solid at a molar ratio of 500:1, and then add 15 drops of ammonia water until the solution becomes colorless again, to prepare a 200 mmol / L metal salt solution;

[0038] (4) Preparation of 2 wt % polyvinyl alcohol aqueous solution: 1 g of polyvinyl alcohol powder was weighed and dissolved in 50 mL of deionized water at 95° C.

[0039] (5) After the sensitization treatment, the second mixed solution is added with silver ammonia solution at a volume ratio of 1:9 and stirred at a speed of 300 rpm for 5 minutes. During this period, the fluorinated graphene silver ammonia mixed solution should be kept in a dark place to avoid the subsequent reaction effect affected by direct light; 30 mL of reducing agent with a volume ratio of 1:3 is added to the above mixed solution to react for 25 minutes. After the reaction time is over, 1 mL of polyvinyl alcohol aqueous solution is added to the mixed solution, and vacuum filtration is performed after ultrasonication. The ionized water and anhydrous ethanol are alternately washed three times; vacuum drying is performed at 50°C for 8 hours, and the filter membrane is peeled off to obtain a fluorinated graphene membrane;

[0040] (6) The prepared fluorinated graphene membrane is cut into 12 mm discs and used directly as electrodes, and metallic lithium is used as a counter electrode to assemble a lithium / carbon fluoride battery. The current value required for the lithium / carbon fluoride battery assembled with the fluorinated graphene membrane to release the capacity within a specified time is the maximum discharge rate.

[0041] The fluorinated graphene film prepared in this embodiment is used to prepare a lithium primary button cell. The specific method includes: the fluorinated graphene film is vacuum dried for 8 hours and then cut into 12 mm pole pieces, the counter electrode is metallic lithium, the diaphragm is a Celgard-2500 series polypropylene diaphragm, and the electrolyte is 1M LiBF4 / PC:DME (1:1); 2025 button cells are used for assembly, and the whole process is carried out in a glove box. The assembly order is negative electrode shell-lithium sheet-electrolyte-diaphragm-electrolyte-electrode sheet-gasket-spring sheet-positive electrode shell. After assembly, it is packaged and finally its performance is tested.

[0042] Embodiment 2

[0043] In this embodiment, the tap density is 0.04-0.05 g / cm 3 , fluorinated graphene with a fluorine content of 55% was used as a raw material to prepare a fluorine content of 33%, a metal particle doping amount of 14.91wt%, and an active material surface loading of 5.05mg / cm 2The fluorinated graphene film has a maximum discharge rate of 5C. The specific implementation is consistent with the first embodiment, except that the concentration of the reaction solution is adjusted to 300mmol / L in step 3 for the experiment.

[0044] Embodiment 3

[0045] In this embodiment, the tap density is 0.04-0.05 g / cm 3 , fluorinated graphene with a fluorine content of 55% was used as a raw material to prepare a fluorine content of 41%, a metal particle doping amount of 8.02wt%, and an active material surface loading of 5.03mg / cm 2 The fluorinated graphene film has a maximum discharge rate of 3C. The specific implementation is consistent with the first embodiment, except that the concentration of the reaction solution is adjusted to 100 mmol / L in step 3 for the experiment.

[0046] Embodiment 4

[0047] In this embodiment, the tap density is 0.04-0.05 g / cm 3 , fluorinated graphene with a fluorine content of 55% was used as a raw material to prepare a fluorine content of 40%, a metal particle doping amount of 11.39wt%, and an active material surface loading of 3.32mg / cm 2 The fluorinated graphene film has a maximum discharge rate of 3C. The specific implementation is consistent with the first embodiment, except that in step 1, the fluorinated graphene and the carbon nanotubes are subjected to an experiment at a mass ratio of 1:1.

[0048] Embodiment 5

[0049] In this embodiment, the tap density is 0.04-0.05 g / cm 3 , fluorinated graphene with a fluorine content of 55% was used as a raw material to prepare a fluorine content of 43%, a metal particle doping amount of 11.65wt%, and an active material surface loading of 5.06mg / cm 2 The fluorinated graphene film has a maximum discharge rate of 5C. The specific implementation is consistent with the first embodiment, except that in step 1, the fluorinated graphene and the carbon nanotubes are subjected to an experiment at a mass ratio of 5:1.

[0050] Embodiment 6

[0051] In this embodiment, the tap density is 0.04-0.05 g / cm 3 , fluorinated graphene with a fluorine content of 55% was used as a raw material to prepare a fluorine content of 34%, a metal particle doping amount of 16.70wt%, and an active material surface loading of 4.98mg / cm 2 The fluorinated graphene film has a battery discharge rate of 5 C. The specific implementation is consistent with the first embodiment, except that the reaction time is adjusted to 40 min in step 5 for the experiment.

[0052] Embodiment 7

[0053] In this embodiment, the tap density is 0.04-0.05 g / cm 3 , fluorinated graphene with a fluorine content of 55% was used as a raw material to prepare a fluorine content of 45%, a metal particle doping amount of 7.45wt%, and an active material surface loading of 4.96mg / cm 2 The fluorinated graphene film has a maximum discharge rate of 3C. The specific implementation is consistent with the first embodiment, except that the reaction time is adjusted to 10 minutes in step 5 for the experiment.

[0054] Embodiment 8

[0055] In this embodiment, the tap density is 0.04-0.05 g / cm 3 , fluorinated graphene with a fluorine content of 55% is used as a raw material, and the specific implementation method is consistent with that of Example 1, except that the amount of polyvinyl alcohol aqueous solution added in step 5 is increased to 10 mL for the experiment.

[0056] In this experiment, the filter membrane was clogged due to the increase in the amount of polyvinyl alcohol, and the mixed slurry solution was not completely filtered, so a complete fluorinated graphene membrane could not be prepared, which was not conducive to the preparation of a fluorinated graphene membrane with multiple effects and the improvement of the electrochemical performance of the battery.

[0057] Comparative Example 1

[0058] Compared with Example 1, the experiment was conducted without adding metal salt solution and reducing agent. The fluorine content of the prepared fluorinated graphene film was 55%, the metal particle doping amount was 0wt%, and the active material surface loading was 5.08mg / cm 2 , the maximum discharge rate of the battery is 1C.

[0059] The fluorine content of the fluorinated graphene film prepared in this experiment is not reduced and the metal particle content is 0wt%, the hydrophilicity of the fluorinated graphene film is not improved and the electrode conductivity is poor, which is not conducive to preparing a fluorinated graphene film with multiple effects and improving the electrochemical performance of the battery.

[0060] Comparative Example 2

[0061] Compared with Example 1, this comparative example was conducted without adding carbon nanotubes. The fluorine content of the prepared fluorinated graphene film was 42%, the metal particle doping amount was 10.60wt%, and the active material surface loading was 5.24mg / cm 2 , the maximum discharge rate of the battery is 2C.

[0062] The fluorinated graphene membrane prepared in this experiment does not add carbon nanotube one-dimensional conductive materials, the transmission path of ions / electrons is reduced, and the conductivity of the electrode is not significantly improved, which is not conducive to the preparation of multi-effect fluorinated graphene membranes and the improvement of the electrochemical performance of the battery.

[0063] Comparative Example 3

[0064] Compared with Example 1, this comparative example was tested only in step 4 without adding the polyvinyl alcohol aqueous solution.

[0065] This experiment cannot prepare a fluorinated graphene film with a self-supporting structure. The fluorinated graphene film cracks after drying and cannot form a film, which is not conducive to preparing a fluorinated graphene film with multiple effects and improving the electrochemical performance of the battery.

[0066] Comparative Example 4

[0067] Compared with Example 1, this comparative example does not add carbon nanotubes, metal salt solution and reducing agent to conduct experiments. The fluorine content of the prepared fluorinated graphene film is 55%, the metal particle doping amount is 0wt%, and the active material surface loading is 4.66mg / cm 2 , the maximum discharge rate of the battery is 0.1C.

[0068] The fluorinated graphene membrane prepared in this experiment lacks carbon nanotubes and conductive metal particles, the transmission path of ions / electrons is reduced, and the conductivity of the electrode is not significantly improved, which is not conducive to the preparation of fluorinated graphene membranes with multiple effects and the improvement of the electrochemical performance of the battery.

[0069] Comparative Example 5

[0070] Compared with Example 1, this comparative example has a tap density of 0.04-0.05 g / cm 3 , fluorine content is 55%, and the fluorinated graphene positive electrode material is prepared by the traditional slurry coating method. Weigh the fluorinated graphene, Ketjen black, and polyvinylidene fluoride in a ratio of 8:1:1; put the polyvinylidene fluoride in a small beaker, add a certain amount of N-methylpyrrolidone and stir it into a gel; mix the surface highly conductive carbon fluoride and the conductive Ketjen black evenly, and then slowly add them to the beaker; add an appropriate amount of N-methylpyrrolidone until a uniformly dispersed slurry is obtained, and then coat it on the carbon-coated aluminum foil with a thickness of 150μm, and vacuum dry it for 10 hours to obtain the electrode; its active material surface loading is 2.01mg / cm 2 , the maximum discharge rate performance of the battery is 3C.

[0071] Comparative Example 6

[0072] The preparation method of this comparative example is the same as that of comparative example 5, both of which are traditional slurry coating methods, and the surface loading of fluorinated graphene active material is >2.01 mg / cm 2 During the drying process of the electrode, the slurry layer of the electrode and the carbon-coated aluminum foil will crack and fall off, and the surface loading of the active material cannot be increased.

[0073] See Table 1 and Table 2 for a comparative summary of the effects of the mass ratio of fluorinated graphene to carbon nanotubes, reaction solution concentration, and reaction time on fluorine content, metal particle doping amount, active material surface loading, water contact angle, and discharge rate in the embodiments of the present invention. It can be seen that:

[0074] (1) See Figure 5 The mass ratio of fluorinated graphene to carbon nanotubes in Example 1 is 4:1, the concentration of the reaction solution is 200 mmol / L, the reaction time is 25 min, the amount of polyvinyl alcohol aqueous solution added is 1 mL, and the prepared fluorinated graphene film is the optimal parameter fluorinated graphene film, whose fluorine content is 35%, and the metal particle doping amount is 12.04%. It is assembled into a lithium primary button battery, and the maximum discharge rate of the battery is 8C.

[0075] (2) By comparing Examples 1, 2, 3, 6, and 7 with Comparative Example 1, it can be concluded that the concentration of the reaction solution and the reaction time have the greatest influence on the fluorine content of the fluorinated graphene film, the amount of metal particles doped, and the battery discharge rate, and have little influence on the surface loading of the active material. Different concentrations of the reaction solution and reaction time result in different defluorination effects on the fluorinated graphene. The reduction of the fluorine content can improve the hydrophilicity of the fluorinated graphene. The hydrophilicity (<90°) can be determined by the contact angle between the fluorinated graphene film and water, see Figure 3 The water contact angle of Example 1 is 60.2°. After comprehensive comparison, it is concluded that the reaction solution concentration and reaction time in Example 1 are the optimal parameters.

[0076] (3) By comparing Examples 1, 4, and 5 with Comparative Example 2, it can be concluded that the proportion of carbon nanotubes has the greatest influence on the surface loading of active substances in the fluorinated graphene film and the battery discharge rate. If the electrode does not contain carbon nanotubes, a conductive network structure cannot be formed, and the conductivity is reduced; when the content is too high, the carbon nanotubes agglomerate and become severely entangled, which in turn reduces the conductivity of the fluorinated graphene film. In addition, the carbon nanotubes have high hardness, and when the content exceeds a certain value, the electrode will easily break and will occupy part of the mass of the fluorinated graphene film, and the active substance surface loading is not significantly increased. After comparison, it is concluded that the ratio of fluorinated graphene to carbon nanotubes in Example 1 is 4:1, which is the optimal parameter.

[0077] (4) See Figure 1 By comparing Examples 1 and 8 with Comparative Example 3, it can be concluded that the amount of polyvinyl alcohol added affects the formation of the electrode self-supporting structure. No addition of polyvinyl alcohol aqueous solution and 10 mL of the added amount will result in the inability to prepare a fluorinated graphene film, which has an impact on the integrity of the fluorinated graphene film. In Example 1, adding 1 mL of polyvinyl alcohol can not only prepare a complete fluorinated graphene film, but also has a certain degree of flexibility. This shows that the amount of polyvinyl alcohol added has an impact on the integrity of the prepared fluorinated graphene film.

[0078] (5) See Figure 4By comparing the infrared spectra of Example 1 with those of the fluorinated graphene material, the hydroxyl peak vibration of Example 1 is significantly enhanced and blue-shifted to 3404 cm -1 The peak is wider, indicating that the added polyvinyl alcohol has abundant hydroxyl groups and hydrogen bonds are formed between the groups.

[0079] (6) See Figure 2 As shown in Table 3, by comparing Example 1 with Comparative Example 4, the fluorinated graphene in Example 1 constructs a connected three-dimensional conductive network structure due to the addition of carbon nanotubes and metal particles, which improves the conductivity of the fluorinated graphene film, effectively reduces voltage hysteresis, and further improves the maximum discharge rate of the battery.

[0080] (7) By comparing Example 1 with Comparative Examples 5 and 6, it can be seen that when the surface loading of fluorinated graphene with low tap density is slightly increased, the electrode prepared by the traditional slurry coating method not only has poor rate performance, but also cannot prepare a complete fluorinated graphene electrode by the slurry coating method under the premise of further increasing the surface loading of active material.

[0081]

[0082] Table 1

[0083]

[0084] Table 2

[0085]

[0086] Table 3

[0087] In summary, the present invention provides a method for preparing a fluorinated graphene membrane and a battery, wherein the fluorinated graphene and carbon nanotubes are mixed and immersed in a mixed solution of anhydrous ethanol and deionized water, a reduction defluorination mixed solution and a polyvinyl alcohol aqueous solution are added, and then vacuum filtration is performed, and the filter membrane is peeled off after drying to obtain a fluorinated graphene membrane. The fluorinated graphene membrane has a fluorine content of 33-45%, a metal particle doping amount of 7.45-16.7wt%, and an active material loading of 3.32-5.24mg / cm 2 , the maximum discharge rate of the battery can reach 8C. The method of the present invention is a one-step continuous process, which reduces the fluorine content of fluorinated graphene by reduction and defluorination, improves the hydrophilicity of fluorinated graphene, and the reduced metal particles construct a conductive metal layer to improve the conductivity; and polyvinyl alcohol is used as an interlayer binder to make the conductive metal particles, carbon nanotubes and fluorinated graphene contact each other, constructing a stable self-supporting three-dimensional conductive network structure, further improving the electrode conductivity and the active material surface loading of low-tap density fluorinated graphene, shortening the transmission path of ions / electrons, reducing polarization during discharge, and realizing the application of lithium / fluorinated carbon batteries in high-power electronic devices.

[0088] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement and improvement made within the scope of the present invention are included in the protection scope of the present invention.

Claims

1. A method for preparing a fluorinated graphene film, characterized in that: The method comprises: The fluorinated graphene and carbon nanotubes are mixed and immersed in a mixed solution of anhydrous ethanol and deionized water, and a reduction and defluorination mixed solution is added to defluorinate the fluorinated graphene and reduce the conductive metal particles; wherein the reduction and defluorination mixed solution is composed of a metal salt solution and a reducing agent; A polyvinyl alcohol aqueous solution having hydroxyl groups and hydrogen bonds between the groups is added as a binder, and the aqueous solution is ultrasonically dispersed and vacuum filtered. After drying, the filter membrane is peeled off to obtain a fluorinated graphene membrane; wherein the fluorine content of the fluorinated graphene membrane is 33-45%, the metal particle doping amount is 7.45-16.7wt%, and the active material surface loading is 3.32-5.24mg / cm 2 .

2. The method for preparing a fluorinated graphene film according to claim 1, characterized in that: The method further comprises: (1) immersing the fluorinated graphene and the carbon nanotubes in an anhydrous ethanol solution, stirring for 10 minutes and then ultrasonicating for 30 minutes, washing with alcohol to remove impurities, and then immersing in deionized water and anhydrous ethanol to form a first mixed solution; (2) adding the first mixed solution to the sensitizing solution at a volume ratio of 1:9 for 1 h, washing to remove impurities and soaking in deionized water and anhydrous ethanol to form a second mixed solution; (3) adding the second mixed solution to 90 mL of a reduction defluorination mixed solution in one step and reacting for 10 to 40 minutes, wherein the volume ratio of the metal salt solution to the reducing agent in the reduction defluorination mixed solution is 3:1; at the end of the time, adding 1 mL of a polyvinyl alcohol aqueous solution to the solution, performing vacuum filtration after ultrasonic treatment for 10 minutes, and repeating the washing with deionized water and anhydrous ethanol three times; wherein the polyvinyl alcohol aqueous solution is prepared by dissolving polyvinyl alcohol powder in deionized water at 95° C.; (4) After the obtained film-formed sample is dried, the filter membrane is peeled off to obtain a fluorinated graphene membrane.

3. The method for preparing a fluorinated graphene film according to claim 2, characterized in that: The tap density of the fluorinated graphene is 0.04-0.05 g / cm 3 , the fluorine content is 50-60%.

4. The method for preparing a fluorinated graphene film according to claim 2, characterized in that: The carbon nanotubes include at least one of multi-walled carbon nanotubes, single-walled carbon nanotubes, carbon nanowires, carbon nanotube bundles, and serpentine carbon nanotubes; the mass ratio of the fluorinated graphene to the carbon nanotubes is 1 to 5:1, and the concentration of the first mixed solution is 5 to 10 mg / mL.

5. The method for preparing a fluorinated graphene film according to claim 2, characterized in that: The formula of the sensitizing solution is that solid stannous chloride and hydrochloric acid solution are dissolved in deionized water and anhydrous ethanol in a volume ratio of 1:

1.

6. The method for preparing a fluorinated graphene film according to claim 2, characterized in that: The reducing agent solution includes at least one of a combination of glucose and sodium citrate, hydrazine, formaldehyde, and dimethylamino borane.

7. The method for preparing a fluorinated graphene film according to claim 2, characterized in that: The metal salt includes at least one of nitrate, chloride and sulfate; and the conductive metal particle is Ag.

8. The method for preparing a fluorinated graphene film according to claim 2, characterized in that: The molecular weight range of polyvinyl alcohol is 120,000 to 150,000.

9. The method for preparing a fluorinated graphene film according to claim 2, characterized in that: The filter membrane includes at least one of a polytetrafluoroethylene membrane, a polyamide membrane, and a glass fiber membrane.

10. A battery, characterized in that: The invention comprises the fluorinated graphene film according to claims 1 to 9.

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