High-specific-capacity three-dimensional porous carbon fluoride aerogel self-supporting composite positive electrode material and preparation method thereof

Abstract

The invention provides a high-specific-capacity three-dimensional porous carbon fluoride aerogel self-supporting composite positive electrode material and a preparation method thereof.The method comprises the steps that carbon, carboxymethyl cellulose and carbon fluoride powder are mixed and dispersed to form a uniform solution, and an ice template method is combined with a liquid nitrogen quick freezing-freeze drying technology to prepare the high-specific-capacity three-dimensional porous carbon fluoride aerogel self-supporting composite positive electrode material. And carrying out subsequent carbonization treatment to obtain the three-dimensional self-supported porous carbon fluoride aerogel composite positive electrode material. According to the invention, the carbon fluoride material for the lithium primary battery is subjected to structure modification, so that the high specific capacity characteristic of carbon fluoride is retained, and meanwhile, a traditional current collector, a binder and a toxic N-methyl pyrrolidone reagent do not need to be used, so that the loading capacity of active substances is further improved; therefore, the lithium primary battery has excellent electrochemical performance under the conditions of high temperature and long-time storage (the specific capacity is 985.1 mAh / g under 0.1 C, the platform voltage reaches 2.61 V, and the monthly self-discharge rate is only 0.8%). The preparation process is simple, and has the characteristics of being green, environment-friendly, safe and non-toxic.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium primary batteries and specifically relates to a high-capacity three-dimensional porous fluorinated carbon aerogel self-supporting composite positive electrode material and a preparation method thereof. Background Art

[0002] Lithium primary batteries have been widely used in aerospace, medical electronics, deep-sea exploration and other fields. According to the classification of positive electrode active materials, typical systems include lithium-manganese dioxide batteries, lithium-thionyl chloride batteries, lithium-sulfur dioxide batteries, lithium-carbon fluoride batteries, etc. Among them, lithium-carbon fluoride batteries have become one of the systems with the most development potential due to their advantages such as high energy density, low self-discharge rate, stable voltage platform and long storage life. However, in practical applications, traditional carbon fluoride positive electrode materials themselves have strong electrical insulation and large resistance, which leads to voltage hysteresis in the initial stage of discharge and hinders the diffusion of lithium ions in the material. At the same time, the discharge product LiF is deposited at the electrode / electrolyte interface in the form of an insulating layer, further blocking the ion transmission channel, limiting the further development and utilization of lithium-carbon fluoride primary batteries.

[0003] In lithium-carbon fluoride battery systems, conductive additives can effectively improve the intrinsic insulating properties of carbon fluoride cathodes by creating efficient electron transport pathways, reducing electrode interface contact resistance, and suppressing polarization. While one-dimensional carbon nanotubes (CNTs) can partially improve reaction kinetics due to their high surface area, their loosely packed tubular structure reduces the volumetric energy density of the electrode. Furthermore, the sheet-like stacking properties of two-dimensional conductive materials like graphene can extend ion transport pathways, triggering concentration polarization at high rates. Furthermore, uneven dispersion of the conductive additive can lead to the formation of localized high-impedance regions.

[0004] The traditional carbon fluoride cathode preparation process involves uniformly mixing carbon fluoride with PVDF and acetylene black, then coating the mixture onto aluminum foil. This process contains a high proportion of inactive ingredients (binders and current collectors), severely limiting the mass energy density of the active material. Furthermore, insufficient interfacial bonding can easily lead to the active material detaching from the current collector. Existing modification strategies (such as conductive agent doping and binder optimization) struggle to simultaneously meet the dual requirements of establishing a continuous conductive network and mitigating discharge volume expansion.

[0005] Therefore, it is of great research significance to construct three-dimensional porous fluorinated carbon aerogel self-supporting positive electrode materials with high specific surface area, rich pore structure and excellent conductivity. Summary of the Invention

[0006] This invention addresses the technical problems inherent in known technologies and the poor conductivity, low actual specific capacity, and rapid self-discharge of existing lithium primary battery cathodes. By employing an ice-templating method, a controlled pore structure is formed through directional freezing and freeze-drying, eliminating the need for template removal and resulting in a green process. The resulting composite cathode effectively improves the poor conductivity of carbon fluoride, and the resulting lithium primary battery exhibits excellent electrochemical performance.

[0007] The present invention adopts a technical solution: a high specific capacity three-dimensional porous fluorinated carbon aerogel self-supporting composite cathode material and a preparation method thereof. The composite cathode material is a self-supporting three-dimensional porous fluorinated carbon aerogel composite cathode material prepared by combining ice template method with freeze drying technology, with carbon as a conductive agent, carboxymethyl cellulose as a binder, and carbon fluoride powder as an active material. Specifically: Fluorinated carbon aerogels are first functionalized with nitric acid and sulfuric acid: the raw carbon is dispersed in a mixed acid solution, heated and stirred, and then filtered and washed with deionized water until the filtrate is neutral. The precipitate is then dried and ground to obtain hydrophilic carbon with oxygen-containing functional groups. Subsequently, carbon, carboxymethyl cellulose, and carbon fluoride powders were placed in an agate mortar and wet-ground with the addition of alcohol. The ground slurry was transferred to a deionized water solution containing carboxymethyl cellulose and stirred evenly to obtain a precursor solution of carbon fluoride aerogel. The precursor solution is injected into a container after ultrasonic crushing, and is quickly frozen and shaped using liquid nitrogen, and then freeze-dried; the freeze-dried carbon fluoride aerogel is moved to a tubular furnace and carbonized in an argon atmosphere to finally obtain a three-dimensional porous carbon fluoride aerogel composite positive electrode material.

[0008] Preferably, the carbon is one or a combination of single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, graphite, graphene, fullerene and carbon nitride.

[0009] Preferably, the mixed acid solution is a mixture of monoprotic acid and diprotic acid, including one or more combinations of nitric acid, hydrochloric acid, and sulfuric acid, and the volume ratio of the monoprotic acid to the diprotic acid is 1:3. Preferably, the fluorinated carbon powder includes one or more of fluorinated graphite, fluorinated hard carbon, fluorinated mesophase carbon spheres, fluorinated carbon fibers and fluorinated carbon nanotubes.

[0010] Preferably, the bottom of the container is a copper rod or a steel pipe, the upper part is covered with a heat-insulating polytetrafluoroethylene tube, the bottom and the upper part are sealed and connected, and the diameter is 12 to 20 mm.

[0011] Preferably, the mass fraction of carbon fluoride is 10% to 90%, and the volume of deionized water is 10 to 25 mL.

[0012] Preferably, during the carbonization treatment of the fluorinated carbon aerogel in an argon atmosphere, the calcination temperature is 200°C to 400°C; the heating rate is 1°C min -1 to 5 ℃ min -1 ; Calcination time is 0.5 hours to 6 hours.

[0013] Preferably, the composite positive electrode material is used to make a lithium primary battery, and the lithium salt in the electrolyte used in the lithium primary battery is a mixture of one or more of lithium bis(trifluorosulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium hexafluorophosphate, lithium tetrafluoroborate, and lithium oxalodifluoroborate.

[0014] The present invention has the following advantages and positive effects: 1. The high-capacity three-dimensional porous fluorinated carbon aerogel self-supporting composite positive electrode material prepared by the present invention can effectively improve the poor conductivity of fluorinated carbon due to its interconnected porous network and high conductivity, thereby improving the performance of lithium primary batteries.

[0015] 2. The raw carbon weakens the covalency of the CF bond through π-π electron coupling, thereby improving the reaction activity.

[0016] 3. The graded pores shorten the ion diffusion path to the micron level, thereby reducing the charge transfer impedance.

[0017] 4. The three-dimensional porous structure of the aerogel provides good support for carbon fluoride, effectively alleviating the volume change during the discharge process and avoiding the collapse of the electrode structure.

[0018] 5. The composite electrode retains CF x The high specific capacity characteristics of the lithium-ion battery are achieved without the need for conventional current collectors or the toxic N-methylpyrrolidone binder, further increasing the active material loading capacity and achieving excellent electrochemical performance of lithium-ion batteries under high temperature and long-term storage conditions.

[0019] The present invention is simple to prepare, green, environmentally friendly, safe and non-toxic, can achieve improvements in electrochemical performance and storage performance through convenient steps, and has good application prospects in preparing lightweight, high-energy-density positive electrodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 SEM photo of fluorinated carbon aerogel in Example 1 of the present invention; Figure 2 1 are nitrogen adsorption-desorption curves of Examples 1, 2 and 3 of the present invention; Figure 3 The XRD patterns and Raman spectra of Example 1, Example 4, Example 5 and the comparative example of the present invention are shown; Figure 4 This is the XPS spectrum of Example 1 of the present invention; Figure 5 0.1 C discharge curves of Example 1 of the present invention and the comparative example; Figure 6 High temperature test performance of the battery of Example 1 of the present invention and the comparative example; Figure 7 Li / CF x Discharge curves of button cells at 0.1 C for 10 to 60 days of storage at room temperature and 55 °C. DETAILED DESCRIPTION

[0021] In order to further disclose the content and features of the present invention, the following examples are given and described in detail with reference to the accompanying drawings: A three-dimensional porous fluorinated carbon aerogel composite cathode material prepared by an ice template method, wherein the composite cathode material is composed of CNTs as a conductive agent, carboxymethyl cellulose (CMC) as a binder and CF x The powder is the active material. The technical solution is as follows: multi-walled carbon nanotubes are first acid-washed with mixed acid and dried to obtain functionalized carbon nanotubes (CNTs). The functionalized carbon nanotubes, carbon fluoride particles, and carboxymethyl cellulose are then wet-grinded and transferred to a deionized water solution containing carboxymethyl cellulose. A uniform precursor solution is formed through magnetic stirring and ultrasonic dispersion. The precursor solution is then dripped into a container and rapidly frozen with liquid nitrogen to form an ice template. The solution is then transferred to a freeze dryer to remove the solvent. Finally, the resulting precursor is carbonized in a tubular furnace under argon protection to obtain a three-dimensional porous carbon fluoride aerogel composite cathode.

[0022] Preferably, the raw material composition includes carbon nanotubes, carboxymethyl cellulose and carbon fluoride, wherein the mass fraction of carbon fluoride is 10% to 90%, and the volume of deionized water is 10 to 25 mL.

[0023] Preferably, during the carbonization treatment of the fluorinated carbon aerogel in an argon atmosphere, the calcination temperature is 200°C to 400°C; the heating rate is 1°C min -1 to 5 ℃ min -1 ; Calcination time is 0.5 hours to 6 hours.

[0024] Example 1: During the preparation of the three-dimensional porous fluorinated carbon aerogel composite electrode, the multi-walled carbon nanotubes (MWCNTs) were first surface functionalized. Specifically, the pristine MWCNTs were dispersed in a mixed acid solution (concentrated nitric acid and sulfuric acid, in a volume ratio of 1:3) and heated with stirring at 70°C for 8 hours. This acidification treatment served a dual purpose: it effectively removed residual amorphous carbon and metal catalyst impurities from the preparation process; it also introduced abundant oxygen-containing functional groups (such as -COOH and -OH) onto the carbon nanotube surface, thereby enhancing the affinity and dispersibility of the acidified MWCNTs. The solution was then filtered and washed repeatedly with deionized water until neutral. The precipitate was then dried at 60°C and ground for later use.

[0025] Preparation of three-dimensional porous fluorinated carbon aerogel self-supporting composite cathode: First, take 10 mL of deionized water as the solvent matrix, weigh 0.05 g of carboxymethyl cellulose (CMC) and disperse it under magnetic stirring until a homogeneous solution is formed. Then, 0.075 g of carbon nanotubes (CNTs), 0.05 g of CMC and 0.408 g of fluorinated carbon (CF x ) powder was placed in an agate mortar and wet-grinded with 1 mL of alcohol for 30 minutes to achieve uniform dispersion. The ground slurry was then transferred to the CMC mother liquor and stirred continuously, ultimately yielding a precursor solution for a three-dimensional porous fluorinated carbon aerogel composite cathode. This precursor solution was ultrasonically treated with a probe for 20 minutes, and 450 μL of the uniformly dispersed solution was then poured into a 16 mm diameter container. The mixture was rapidly frozen with liquid nitrogen to achieve a fixed shape and then freeze-dried for 48 hours. Following freeze-drying, the temperature was increased to 280°C in an argon atmosphere at 2°C / min and then maintained at this temperature for 3 hours. This resulted in a three-dimensional porous fluorinated carbon aerogel composite cathode material.

[0026] The CR2032 button battery shell is used for assembly, and the positive electrode shell, positive electrode, electrolyte, separator, electrolyte, Li negative electrode, nickel foam and negative electrode shell are assembled in sequence.

[0027] Example 2: First, 20 mL of deionized water was taken as the solvent matrix, and 0.05 g of carboxymethyl cellulose (CMC) was weighed and dispersed by magnetic stirring until a homogeneous solution was formed. Then, 0.075 g of carbon nanotubes (CNTs), 0.05 g of CMC and 0.408 g of carbon fluoride (CF x) in an agate mortar and pestle, adding 1 mL of alcohol and wet grinding for 30 minutes to achieve uniform dispersion. The ground slurry was then transferred to the CMC mother liquor and stirred continuously, ultimately obtaining a precursor solution for a three-dimensional porous fluorinated carbon aerogel composite cathode. This precursor solution was ultrasonically treated with a probe for 20 minutes, and 450 μL of the uniform dispersion was poured into a 16 mm diameter container. The container was rapidly frozen with liquid nitrogen to achieve a fixed shape and then freeze-dried for 48 hours. After freeze-drying, the temperature was increased to 280°C in an argon atmosphere at 2°C / min and then maintained at this temperature for 3 hours. This resulted in a three-dimensional porous fluorinated carbon aerogel composite cathode material.

[0028] Completely the same as in Example 1, CR2032 type Li / CF x Button battery.

[0029] Example 3: First, 25 mL of deionized water was taken as the solvent matrix, and 0.05 g of carboxymethyl cellulose (CMC) was weighed and dispersed under magnetic stirring until a homogeneous solution was formed. Then, 0.075 g of carbon nanotubes (CNTs), 0.05 g of CMC and 0.408 g of carbon fluoride (CF x ) in an agate mortar and pestle, adding 1 mL of alcohol and wet grinding for 30 minutes to achieve uniform dispersion. The ground slurry was then transferred to the CMC mother liquor and stirred continuously, ultimately obtaining a precursor solution for a three-dimensional porous fluorinated carbon aerogel composite cathode. This precursor solution was ultrasonically treated with a probe for 20 minutes, and 450 μL of the uniform dispersion was poured into a 16 mm diameter container. The container was rapidly frozen with liquid nitrogen to achieve a fixed shape and then freeze-dried for 48 hours. After freeze-drying, the temperature was increased to 280°C in an argon atmosphere at 2°C / min and then maintained at this temperature for 3 hours. This resulted in a three-dimensional porous fluorinated carbon aerogel composite cathode material.

[0030] Completely the same as in Example 1, CR2032 type Li / CF x Button battery.

[0031] Example 4: First, 10 mL of deionized water was taken as the solvent matrix, and 0.05 g of carboxymethyl cellulose (CMC) was weighed and dispersed by magnetic stirring until a homogeneous solution was formed. Then, 0.075 g of carbon nanotubes (CNTs), 0.05 g of CMC and 0.408 g of carbon fluoride (CF x) in an agate mortar and pestle, adding 1 mL of alcohol and wet grinding for 30 minutes to achieve uniform dispersion. The ground slurry was then transferred to the CMC mother solution and stirred continuously, ultimately obtaining a precursor solution for a three-dimensional porous fluorinated carbon aerogel composite cathode. This precursor solution was ultrasonically treated with a probe for 20 minutes, and 450 μL of the uniform dispersion was then poured into a 16 mm diameter container. The product was rapidly frozen with liquid nitrogen to achieve a fixed shape and then freeze-dried for 48 hours. Following freeze-drying, the temperature was increased to 200°C in an argon atmosphere at 2°C / min and then maintained at this temperature for 3 hours. This resulted in a three-dimensional porous fluorinated carbon aerogel composite cathode material.

[0032] Completely the same as in Example 1, CR2032 type Li / CF x Button battery.

[0033] Example 5: First, 12 mL of deionized water was taken as the solvent matrix, and 0.05 g of carboxymethyl cellulose (CMC) was weighed and dispersed under magnetic stirring until a homogeneous solution was formed. Then, 0.075 g of carbon nanotubes (CNTs), 0.05 g of CMC and 0.408 g of carbon fluoride (CF x ) powder was placed in an agate mortar and wet-ground with 1 mL of alcohol for 30 minutes to achieve uniform dispersion. The ground slurry was then transferred to the CMC mother solution and stirred continuously, ultimately yielding a precursor solution for a three-dimensional porous fluorinated carbon aerogel composite cathode. This precursor solution was ultrasonically treated with a probe for 20 minutes, and 450 μL of the uniform dispersion was then poured into a 16 mm diameter container. The mixture was rapidly frozen with liquid nitrogen to achieve a fixed shape and then freeze-dried for 48 hours. Following freeze-drying, the temperature was increased to 400°C in an argon atmosphere at 2°C / min and then maintained at this temperature for 3 hours. This resulted in a three-dimensional porous fluorinated carbon aerogel composite cathode material.

[0034] Completely the same as in Example 1, CR2032 type Li / CF x Button battery.

[0035] Comparative Example: The present invention also provides an existing preparation method as a comparative example, and the specific process is as follows.

[0036] The positive electrode is CF x (F content ≥ 61%, particle size < 25 μm) is the active material, PVDF is the binder and Super P is the conductive agent. According to the mass percentage of 80% CF xThe raw materials were weighed in a mass ratio of 10% PVDF, 10% Super P, and thoroughly ground and mixed in an agate mortar. An appropriate amount of N-methylpyrrolidone (NMP) solvent was then added. The slurry was stirred continuously with a magnetic stirrer for 12 hours until uniform dispersion was achieved. It was then coated onto an aluminum foil current collector. The slurry was then vacuum-dried at 80°C for 12 hours, removed, and stamped using a mold to produce an electrode sheet with a diameter of 14 mm. The remaining procedures were identical to those of Example 1, and the CR2032 Li / CF3 was assembled. x Button battery.

[0037] The three-dimensional porous fluorinated carbon aerogel self-supporting composite positive electrode prepared by the present invention was tested and characterized. Figure 1 (a) is an optical photograph of the three-dimensional porous fluorinated carbon aerogel self-supporting composite positive electrode produced by the present invention. Figure 1 The concentrations of (b), (c) and (d) are SEM photos of Example 1, showing a clear layered structure with regular arrangement between layers. The layered structure provides support for the aerogel. The layers are interconnected and extend uniformly in the longitudinal direction, which improves the mechanical properties of the aerogel structure. Figure 1 In the dotted box in (c), it can be noticed that there are multiple stacked sheets, indicating that CF x Successfully loaded on the aerogel skeleton. Under high magnification ( Figure 1 In (d), it can be seen that the lamellar structure is composed of interwoven CNT binder CMC.

[0038] Figure 2 (a), (b), and (c) are the adsorption and desorption curves and pore size distribution curves of Example 1, Example 2, and Example 3, respectively. The three belong to the IV type isotherm of the H3 hysteresis loop, which is a typical mesoporous structure. As the water content increases (Example 1, Example 2, and Example 3), the hysteresis loop gradually widens and the adsorption amount gradually increases. Figure 2 As shown in (a), the adsorption amount rises rapidly in the low relative pressure region (P / P0<0.3) and then slows down, indicating that Example 1 is mainly composed of small mesopores (<10 nm) and has a low specific surface area. Figure 2 In (b), an obvious hysteresis loop appears in the P / P0<0.2-0.5 region. Figure 2 In (c), the desorption curve for P / P0 > 0.4 separates from the adsorption curve, forming a distinct hysteresis loop, indicating the presence of a larger pore structure. The pore size distribution shifts toward larger pores from Examples 1 to 3, with an increased distribution width, indicating an increase in the average pore size and a decrease in pore size uniformity.

[0039] Figure 3(a) shows the XRD patterns of Examples 1, 4, and 5 of the present invention. The fluorinated carbon phase (PDF#30-0476) exhibits three characteristic diffraction peaks. The XRD peak intensity of Example 4 is further reduced. This is because the carbonization temperature in Example 4 is relatively low (200°C), and CMC begins to decompose and carbonize, producing amorphous carbon that covers or embeds the CF. x The crystal surface reduces the order of the crystal, weakens the intensity of the diffraction signal, and slightly moves the peak position. In Example 5 (400 ° C), the diffraction peak intensity of 12.5 ° drops sharply. This is because the high temperature promotes the complete carbonization of CMC, forming a continuous carbon network, which wraps a large amount of CF x particles, significantly destroying CF x (001) plane of highly fluorinated carbon in the original crystal. Figure 3 (b) is a Raman spectrum to study the effect of carbonization temperature on the degree of aerogel defects and graphitization. Figure 3 (b) in Example 1, Example 4 and Example 5 at 1300 cm −1 and 1580 cm −1 There are two obvious vibration peaks near the carbon atoms, which correspond to the D peak representing the disorder and defect degree of carbon atoms and the sp peak representing the carbon atoms. 2 The G peak of the hybrid structure is calculated by calculating the intensity ratio of these two characteristic peaks (I D / I G ) to reflect the degree of defects and graphitization of the sample. The larger the ratio, the lower the degree of graphitization of the material and the richer the defects. D / I G The values ​​are 0.851, 0.846 and 0.855 respectively.

[0040] Figure 4 The XPS spectrum provided for Example 1 of the present invention is Figure 4 The peaks at 285.15 and 688.15 eV shown in (a) indicate the presence of C and F elements, accompanied by a small amount of oxygen, which may come from surface oxygen-containing functional groups or trace oxides introduced during the preparation process. Figure 4 The peak fitting of (b) shows that the existence of CF bond (including covalent CF (292.0 eV) and semi-ionic bond CF (290.0 eV)) directly proves the chemical combination of carbon and fluorine, which is the key structure of the active component of carbon fluoride. Figure 4 (c) in the figure is fitted with three states of fluorine species, which are semi-ionic (C x F) n The binding energy is 688.8 V, and the covalent CF xThe binding energy of CF2 / CF3 is 689.1 eV, and the binding energy of CF2 / CF3 is 690.0 eV. Fluorinated carbon aerogel adjusts the type of CF bond to obtain higher active sites, reduces the content of inert -CF2 and -CF3, increases the content of semi-ion CF, and improves CF x Conductivity, at the same time, the low energy CF bond in CF x It is easier to break during the discharge process, making Li / CF x The battery has better discharge behavior.

[0041] Figure 5 The discharge curves at 0.1 C are provided for Example 1 of the present invention and the comparative example. The specific capacity of the example is 985.1 mAh / g, and the platform voltage reaches 2.61 V.

[0042] Figure 6 The discharge curves and impedance curves at high temperatures of 75°C and 85°C are provided for Example 1 and the comparative example of the present invention. The corresponding discharge specific capacities of the comparative example and Example 1 are 886 and 1030 mAh / g, respectively. The R ct 141.8 and 75.8Ω respectively; while the specific capacity at 85 ℃ is 841 and 1000 mAh / g, the R ct 188.8 and 124.2 Ω, respectively. At high temperature, Example 1 has higher specific capacity and lower transfer resistance. At the same time, the discharge specific capacity at this temperature is higher than that at room temperature. It may be that the increase in temperature promotes the reaction kinetics and accelerates ion migration.

[0043] Figure 7 Li / CF of the comparative example and Example 1 of the present invention x The discharge curves of button batteries stored at room temperature and 55°C for 10 to 60 days at 0.1 C conditions show that after storage at room temperature for 10, 20, 30 and 60 days, the discharge specific capacities of Example 1 are 967, 959, 919 and 875 mAh / g, respectively; while when stored at 55°C for the same time, the discharge specific capacities are 961, 900, 887 and 864 mAh / g, respectively. In contrast, the comparative example lacks a continuous conductive network, which is prone to increase in internal resistance due to aggregation of active materials, and self-discharge is fast. After storage at room temperature for 10, 20, 30 and 60 days, the discharge specific capacities at 0.1 C are 862, 807, 789 and 704 mAh / g, respectively. At 55°C, they are 740, 686, 603 and 534 mAh / g, and the discharge specific capacity and discharge platform voltage drop sharply. According to the self-discharge formula (η refers to the self-discharge rate of the battery (%), c0 is the rated capacity (mAh / g), that is, the discharge capacity of the battery before storage, and c is the discharge capacity of the battery after storage (mAh / g)) It can be calculated that the monthly self-discharge rate of the battery assembled in Example 1 is 0.8%, and that of the comparative example is 2.66%, indicating that the three-dimensional porous fluorinated carbon aerogel composite negative and positive electrodes have good storage stability.

[0044] Although preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above-described specific embodiments. The above-described specific embodiments are merely adaptable and not restrictive. Those skilled in the art, guided by the present invention, may devise various embodiments without departing from the spirit of the present invention and the scope of protection of the claims. All such embodiments fall within the scope of protection of the present invention.

Claims

1. A high specific capacity three-dimensional porous fluorinated carbon aerogel self-supporting composite cathode material and its preparation method, characterized by: The composite cathode material is a self-supporting three-dimensional porous fluorinated carbon aerogel composite cathode material prepared by combining ice template method with freeze drying technology, with carbon as a conductive agent, carboxymethyl cellulose as a binder, and carbon fluoride powder as an active material. Specifically: Fluorinated carbon aerogels are first functionalized with nitric acid and sulfuric acid: the raw carbon is dispersed in a mixed acid solution, heated and stirred, and then filtered and washed with deionized water until the filtrate is neutral. The precipitate is then dried and ground to obtain hydrophilic carbon with oxygen-containing functional groups. Subsequently, carbon, carboxymethyl cellulose, and carbon fluoride powders were placed in an agate mortar and wet-grinded with alcohol; The grinding slurry is transferred to a deionized water solution containing carboxymethyl cellulose, and stirred evenly to obtain a precursor solution of fluorinated carbon aerogel; The precursor solution is injected into a container after ultrasonic crushing, and is quickly frozen and shaped using liquid nitrogen, and then freeze-dried; the freeze-dried carbon fluoride aerogel is moved to a tubular furnace and carbonized in an argon atmosphere to finally obtain a three-dimensional porous carbon fluoride aerogel composite positive electrode material.

2. The high specific capacity three-dimensional porous fluorinated carbon aerogel self-supporting composite cathode material and preparation method thereof according to claim 1, characterized in that: The carbon is one or a combination of single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, graphite, graphene, graphene oxide and fullerene.

3. The high specific capacity three-dimensional porous fluorinated carbon aerogel self-supporting composite cathode material and preparation method thereof according to claim 1, characterized in that: The mixed acid solution is a mixture of monoprotic acid and diprotic acid, including one or more combinations of nitric acid, hydrochloric acid, and sulfuric acid, and the volume ratio of the monoprotic acid to the diprotic acid is 1:

3.

4. The high specific capacity three-dimensional porous fluorinated carbon aerogel self-supporting composite cathode material and preparation method thereof according to claim 1, characterized in that: The fluorinated carbon powder includes one or more of fluorinated graphite, fluorinated hard carbon, fluorinated mesophase carbon spheres, fluorinated carbon fibers and fluorinated carbon nanotubes.

5. The high specific capacity three-dimensional porous fluorinated carbon aerogel self-supporting composite cathode material and preparation method thereof according to claim 1, characterized in that: The bottom of the container is a copper rod or steel pipe, the upper part is covered with a heat-insulating polytetrafluoroethylene tube, the bottom and the upper part are sealed and connected, and the diameter is 12-20 mm.

6. The high specific capacity three-dimensional porous fluorinated carbon aerogel self-supporting composite cathode material and preparation method thereof according to claim 1, characterized in that: The mass fraction of carbon fluoride is 10%~90%, and the volume of deionized water is 10~25 mL.

7. The high specific capacity three-dimensional porous fluorinated carbon aerogel self-supporting composite cathode material and preparation method thereof according to claim 1, characterized in that: During the carbonization treatment of fluorinated carbon aerogel in argon atmosphere, the calcination temperature was 200 ℃ to 400 ℃; the heating rate was 1 ℃ min -1 to 5 ℃ min -1 ; Calcination time is 0.5 hours to 6 hours.

8. The high specific capacity three-dimensional porous fluorinated carbon aerogel self-supporting composite cathode material and preparation method thereof according to claim 1, characterized in that: The composite positive electrode material is used to make a lithium primary battery. The lithium salt in the electrolyte used in the lithium primary battery is a mixture of one or more of lithium bis(trifluorosulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium hexafluorophosphate, lithium tetrafluoroborate, and lithium oxalodifluoroborate.

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