Application of three-dimensional carbon fiber skeleton membrane modified by copper nanoparticles gradient in aqueous zinc metal battery

Abstract

The application discloses application of a copper nanoparticle gradient modified three-dimensional carbon fiber framework film in a water-based zinc metal battery, and the water-based zinc metal battery comprises a diaphragm and a zinc foil as an anode; and a preparation method of the copper nanoparticle gradient modified three-dimensional carbon fiber framework film comprises the following steps: uniformly dropping copper acetate solution onto a laid filter paper, so that the copper acetate solution penetrates into the filter paper from top to bottom, and in the penetration process, the copper acetate dissolved in the solution is adsorbed by the filter paper, and the content of the copper acetate in the filter paper is reduced from top to bottom; after the filter paper with the gradient adsorbed copper acetate is dried, heat treatment is carried out on the filter paper in a hydrogen-argon mixed atmosphere at 300-400 DEG C, so that the copper nanoparticle gradient modified three-dimensional carbon fiber framework film is obtained; the copper nanoparticle gradient modified three-dimensional carbon fiber framework film is placed between the zinc foil and the diaphragm as an auxiliary anode, and the copper-rich side of the copper nanoparticle gradient modified three-dimensional carbon fiber framework film is close to the zinc foil, and the copper-poor side is close to the diaphragm.

Description

Technical Field

[0001] This invention relates to the field of aqueous zinc metal battery technology, specifically to the application of a three-dimensional carbon fiber skeleton membrane modified with copper nanoparticle gradient in aqueous zinc metal batteries. Background Technology

[0002] Metallic zinc has a low electrode potential (-0.76V compared to the standard hydrogen electrode) and a high theoretical capacity (820mAh g). -1 Or 5855mAh cm -3 Zinc metal batteries, with their advantages of being non-toxic and abundant, have attracted considerable interest as an ideal anode material for aqueous batteries. However, uncontrolled zinc deposition can lead to fatal zinc dendrite growth, thus degrading cycle life. Low redox potentials can induce hydrogen evolution reaction at the zinc anode, increasing the local pH near the anode and triggering zinc corrosion, resulting in irreversible byproducts on the anode. To promote the commercial application of aqueous zinc metal batteries, it is urgent to achieve uniform, stable, and reversible zinc deposition / stripping cycles to obtain long-life, high-rate zinc anodes.

[0003] To overcome the problems of dendrite growth, hydrogen evolution, and surface passivation in zinc anodes, various strategies have been investigated, including interface engineering, electrolyte optimization, and zinc anode structural design. Patent application CN116364838A discloses a multifunctional ferroelectric polymer protective coating for zinc anodes; patent application CN115312704A discloses a zinc anode modified with a material rich in oxygen sites; and patent application CN110148704A discloses a structural design for a network-like lightweight zinc electrode. Currently, zinc electrodes can achieve good cycle stability at low current densities and low areal capacities. However, at high current densities and high areal capacities, the cycle performance of zinc electrodes remains unsatisfactory. The main reason is that conventional zinc electrodes use 2D zinc foils, which have a very limited surface area. Zinc deposition / stripping must be concentrated on the limited surface of the zinc foil. Therefore, high current densities inevitably lead to high Zn content. 2+ Flux, and requires Zn 2+ Rapid transfer / diffusion. For artificial or in-situ solid electrolyte interface (SEI) films with zinc anodes, their low ionic conductivity and low Zn content... 2+ The number of transfers is insufficient for high-throughput Zn 2+The transport requirements of zinc anodes are a challenge. While 3D zinc anodes can partially achieve this goal, they are not the most perfect solution. The three-dimensional structure increases the surface area of ​​the zinc anode, reducing the zinc deposition overpotential. However, traditional three-dimensional zinc anodes face an unavoidable problem: zinc is primarily deposited on the upper surface. This phenomenon is particularly severe at high current densities, leading to rapid dendrite growth. Furthermore, 3D pure zinc anodes are prone to collapse under high current and high capacity conditions. Moreover, 3D zinc anodes lose the advantages of low cost and ease of processing found in 2D zinc foil. For 3D non-zinc anodes, the zinc plating amount is very limited, typically less than 10 mAh cm⁻¹. -2 It is insufficient for large-capacity charge and discharge reactions. Summary of the Invention

[0004] This invention provides an application of a copper nanoparticle gradient-modified three-dimensional carbon fiber skeleton membrane (hereinafter referred to as three-dimensional carbon fiber skeleton membrane@copper) in an aqueous zinc metal battery. The synthesis process of the three-dimensional carbon fiber skeleton membrane@copper is simple and mild, and the structure is unique. As an auxiliary anode, it can significantly improve the cycle performance of the zinc metal anode.

[0005] An application of a copper nanoparticle gradient-modified three-dimensional carbon fiber skeleton membrane in an aqueous zinc metal battery, the aqueous zinc metal battery comprising a separator and zinc foil as an anode, the preparation method of the copper nanoparticle gradient-modified three-dimensional carbon fiber skeleton membrane comprising: uniformly dropping a copper acetate solution onto a flat filter paper, allowing the copper acetate solution to permeate into the filter paper from top to bottom, during which the copper acetate dissolved in the solution is adsorbed by the filter paper, and the copper acetate content in the filter paper decreases gradually from top to bottom; after drying the filter paper with the gradient adsorption of copper acetate, it is heat-treated at 300-400℃ in a hydrogen-argon mixed atmosphere to obtain the copper nanoparticle gradient-modified three-dimensional carbon fiber skeleton membrane.

[0006] The copper nanoparticle gradient-modified three-dimensional carbon fiber skeleton film is placed between the zinc foil and the separator as an auxiliary anode, with the copper-rich side of the copper nanoparticle gradient-modified three-dimensional carbon fiber skeleton film close to the zinc foil and the copper-poor side close to the separator.

[0007] In the three-dimensional carbon fiber skeleton membrane@copper of the present invention, the three-dimensional carbon fiber skeleton membrane is a three-dimensional skeleton structure formed by cross-linking of carbon fibers. The carbon fibers on one surface of the membrane have virtually no copper nanoparticles, while the carbon fibers on the other surface are uniformly adhered with copper nanoparticles. The copper nanoparticles are distributed in a gradient from one surface to the other along the thickness direction of the membrane.

[0008] In one embodiment, in the preparation method of the copper nanoparticle gradient-modified three-dimensional carbon fiber skeleton membrane, the filter paper is made of cotton fiber, which can enhance the adsorption of copper acetate. Specifically, the three-dimensional carbon fiber skeleton membrane in the copper layer can be formed by the carbonization and decomposition of qualitative or quantitative commercial filter paper made of cotton fiber.

[0009] In a further preferred embodiment, after heat treatment at 300–400℃, the surface layer of the cotton fiber decomposes into carbon, while the core of the fiber remains cotton.

[0010] The copper nanoparticles in the three-dimensional carbon fiber skeleton film modified with copper nanoparticle gradients can have a particle size of 1–50 nm.

[0011] In a preferred embodiment, in the method for preparing the copper nanoparticle-modified three-dimensional carbon fiber framework film, the concentration of the copper acetate solution is 1–40 g / L, and the amount of the copper acetate solution used is 0.3–0.4 mL / cm³. 2 The filter paper is immersed in the copper acetate solution for 5.5 to 6.5 hours.

[0012] In the preparation method of the copper nanoparticle gradient modified three-dimensional carbon fiber skeleton film, the drying temperature can be 55-65℃, and the drying time can be 1.5-2.5h.

[0013] In the method for preparing the three-dimensional carbon fiber skeleton film modified by copper nanoparticle gradient, the heating rate of the heat treatment can be 4 to 6 °C / min.

[0014] In the preparation method of the three-dimensional carbon fiber skeleton film modified by copper nanoparticle gradient, the holding time at 300-400℃ can be 1.5-2.5h.

[0015] This invention utilizes the limited, top-to-bottom penetration of copper acetate solution along the thickness of filter paper by gravity, combined with the strong adsorption of cotton fibers, to achieve a gradient adsorption and distribution of copper acetate along the thickness of the filter paper. Then, carbonization is performed at 300–400°C in a hydrogen-argon mixed atmosphere, causing the surface layer of the cotton fibers to decompose into carbon, while the core remains cotton. The copper acetate decomposes into copper nanoparticles, thus obtaining a three-dimensional carbon fiber skeleton membrane@copper. This invention features a simple, mild synthesis process and low cost.

[0016] Compared with the prior art, the beneficial effects of this invention are as follows:

[0017] 1. When the filter paper is laid flat, the solution can only penetrate into the filter paper from top to bottom. The copper acetate dissolved in the solution will be adsorbed by the cotton fibers of the filter paper. By controlling the solution concentration and soaking time, it is possible to allow only a portion of the solution to penetrate into the filter paper. This synergistic effect of limited solution penetration and strong adsorption by cotton fibers results in the copper acetate being adsorbed and distributed in a gradient from top to bottom within the cotton fibers of the filter paper.

[0018] 2. Through low-temperature calcination in a hydrogen-argon mixed atmosphere, the surface layer of the filter paper's cotton fibers decomposes into carbon, while the core of the fiber remains cotton. Therefore, the carbonized three-dimensional carbon fiber skeleton membrane still possesses good toughness and can be used directly as a flexible electrode. The decomposed carbon is hydrophilic, ensuring affinity for aqueous electrolytes. The decomposed carbon is not zinc-loving, solving the problem of zinc dendrite growth on the top surface of the carbon fiber membrane.

[0019] 3. A three-dimensional carbon fiber framework membrane with copper as an auxiliary anode is placed between the zinc foil anode and the separator. The copper-rich surface is closer to the zinc foil, and the copper-poor surface is closer to the separator. Copper has a strong affinity for zinc, causing zinc ions diffused through the carbon fiber membrane to be captured by copper particles on the carbon fiber surface and deposited. The copper nanoparticles are gradient-distributed within the three-dimensional carbon fiber membrane, guiding zinc deposition from bottom to top within the carbon fiber framework membrane. This allows Zn on the zinc foil to be deposited... 2+ The reduced and homogenized flux, along with the weakened and homogenized electric field on the zinc foil, altered the growth pattern of zinc deposits on the foil, resulting in fine, uniform zinc deposits without the growth of upright zinc dendrites. This improved the cycle life of the zinc electrode under high current and high surface capacitance. The zinc deposited on the 3D carbon fiber skeleton film@copper continues to participate in the zinc deposition / stripping cycle reaction during subsequent charge-discharge cycles, gradually making the 3D carbon fiber skeleton film@copper an additional anode, equally important as the zinc foil anode, alongside it. Both anodes participate in the charge-discharge reaction together. Therefore, the 3D carbon fiber skeleton film@copper serves as both an auxiliary electrode and an anode.

[0020] 4. The three-dimensional carbon fiber skeleton membrane@copper also reduces the overpotential of zinc foil under high current, increases the exchange current density of zinc foil, and promotes zinc deposition; it reduces the nucleation overpotential of zinc foil and lowers the nucleation energy barrier; it reduces the corrosion current, increases the corrosion potential, and inhibits the hydrogen evolution reaction of zinc foil corrosion; it reduces the activation energy, accelerates the desolvation process of zinc ions, increases the zinc ion transference number, and accelerates zinc ion migration; it inhibits side reactions and byproducts, and improves coulombic efficiency. Therefore, the three-dimensional carbon fiber skeleton membrane@copper as an auxiliary anode can significantly improve the battery performance of zinc foil. Attached Figure Description

[0021] Figure 1 Digital photographs of the copper-rich and copper-poor surfaces of the three-dimensional carbon fiber skeleton film @ copper prepared for the example;

[0022] Figure 2 Scanning electron microscope (SEM) image of the copper-rich surface of the three-dimensional carbon fiber skeleton film@copper prepared for the example;

[0023] Figure 3 Transmission electron microscope (TEM) image of copper-rich carbon fibers in a three-dimensional carbon fiber skeleton film@copper prepared for the example.

[0024] Figure 4SEM image of the copper-poor surface of the three-dimensional carbon fiber skeleton film@copper prepared for the example;

[0025] Figure 5 X-ray diffraction (XRD) pattern of a three-dimensional carbon fiber skeleton film@copper prepared for the example;

[0026] Figure 6 The three-dimensional carbon fiber skeleton film@copper-assisted zinc foil, the three-dimensional carbon fiber skeleton film@copper-assisted zinc foil, and the bare zinc foil were used to construct symmetrical cells at a current density of 10 mA / cm². -2 and area capacity 2mAh cm -2 Cyclic performance graph;

[0027] Figure 7 The three-dimensional carbon fiber skeleton film@copper-assisted zinc foil prepared for the example, wherein the three-dimensional carbon fiber skeleton film assists the zinc foil, and the bare zinc foil is subjected to a current density of 2 mA / cm². -2 Nucleation overpotential diagram;

[0028] Figure 8 The three-dimensional carbon fiber skeleton film@copper-assisted zinc foil prepared for the example, the three-dimensional carbon fiber skeleton film assisted zinc foil, and the bare zinc foil at a scanning rate of 1 mV / s -1 Tafel curve;

[0029] Figure 9 For the examples, asymmetric cells constructed from a three-dimensional carbon fiber skeleton film@copper-assisted zinc foil, a three-dimensional carbon fiber skeleton film@copper-assisted zinc foil, and bare zinc foil were respectively tested at 1 mA / cm². -2 and 1mAh cm -2 Coulomb efficiency diagram;

[0030] Figure 10 The three-dimensional carbon fiber skeleton film @ copper-assisted zinc foil prepared for the example was at 10 mA cm -2 and 2mAh cm -2 SEM images of the surface after 250 charge-discharge cycles;

[0031] Figure 11 The three-dimensional carbon fiber skeleton film @ copper-assisted zinc foil prepared for the example was at 10 mA cm -2 and 10mAh cm -2 SEM image of the cross section after zinc deposition. Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0033] Place a 6cm diameter circular filter paper flat on the bottom of a petri dish. Dissolve 250mg of copper acetate in 10mL of deionized water, and add the resulting copper acetate solution evenly dropwise onto the filter paper. After the filter paper has been immersed in the copper acetate solution for 6 hours, remove it and dry it at 60℃ for 2 hours. Finally, under a hydrogen-argon mixed atmosphere, dry at 5℃ for 1 minute. -1 The temperature was increased to 350℃ and held for 2 hours. A three-dimensional carbon fiber skeleton membrane was obtained at copper.

[0034] Figure 1 This is a digital photograph of a three-dimensional carbon fiber skeleton membrane over copper, with one surface appearing reddish-black. Figure 1 The left side indicates the presence of a large amount of copper, making it a copper-rich surface; the other surface is pure black. Figure 1 The right side indicates that there is virtually no copper, making it a copper-poor surface.

[0035] Figure 2 The image shows a copper-rich surface of a three-dimensional carbon fiber skeleton membrane over copper, revealing a large number of ultrafine copper nanoparticles on the carbon fiber surface. Figure 3 These are TEM images of the copper-rich surface, confirming the uniform distribution of copper nanoparticles on the carbon fiber surface. The size of the copper nanoparticles ranges from 5 to 30 nm. The coverage area of ​​the copper nanoparticles is limited, with some carbon fiber surfaces still exposed.

[0036] Figure 4 This is a SEM image of the copper-depleted surface of the 3D carbon fiber skeleton membrane over copper, showing smooth, clean, and exposed carbon fibers. Copper particles are virtually absent from the carbon fibers. It can be inferred that the copper nanoparticles exhibit a gradient distribution between the two surfaces of the 3D carbon fiber skeleton membrane.

[0037] Figure 5 The X-ray diffraction (XRD) pattern of the three-dimensional carbon fiber skeleton film@copper shows good agreement with Cu (JCPDS No. 04-0836) at diffraction peaks at 43.3°, 50.4°, and 74.1°. The average particle size of copper is calculated to be 17.7 nm using the Scherrer equation. The presence of humps between 10° and 30° indicates the presence of amorphous carbon.

[0038] Both symmetrical and asymmetrical (or asymmetric) cells were assembled in air using CR2025 button cells. A 2mol L... -1Zinc sulfate aqueous solution and Whatman glass fiber filter paper were used as the electrolyte and separator, respectively. In the symmetrical cell, a three-dimensional carbon fiber skeleton membrane@copper was placed between the zinc foil and the separator as an auxiliary anode, with the copper-rich surface close to the zinc foil and the copper-poor surface close to the separator. In the asymmetrical cell, zinc foil and copper foil were used together, and the three-dimensional carbon fiber skeleton membrane@copper was placed between the zinc foil and the separator, and between the copper foil and the separator, as an auxiliary electrode. Between the zinc foil and the separator, the copper-rich surface of the three-dimensional carbon fiber skeleton membrane@copper was close to the zinc foil, and the copper-poor surface was close to the separator; between the copper foil and the separator, the copper-rich surface of the three-dimensional carbon fiber skeleton membrane@copper was close to the copper foil, and the copper-poor surface was close to the separator. As a contrast, filter paper without copper acetate loading was carbonized using the same process to obtain a pure three-dimensional carbon fiber skeleton membrane, and then symmetrical and asymmetrical cells were assembled using the above method. Also, symmetrical and asymmetrical cells were assembled using the above method without zinc foil used with the auxiliary electrode, also called bare zinc foil.

[0039] Figure 6 Symmetrical cells constructed using a three-dimensional carbon fiber skeleton membrane@copper-assisted zinc foil, a three-dimensional carbon fiber skeleton membrane@copper-assisted zinc foil, and bare zinc foil were used at a current density of 10 mA / cm². -2 and area capacity 2mAh cm -2 The cycling performance diagrams are shown. The three-dimensional carbon fiber skeleton film@copper-assisted zinc foil exhibits the most stable charge-discharge cycle life, reaching 1200 hours; while the cycle life of the three-dimensional carbon fiber skeleton film-assisted zinc foil is only 230 hours. Bare zinc exhibits severe voltage fluctuations and short-circuit after only 140 hours. The magnified voltage-time curves show the voltage hysteresis of the three symmetrical cells from 50 to 50.6 hours. The three-dimensional carbon fiber skeleton film@copper-assisted zinc foil has the smallest voltage hysteresis, approximately 33 mV. The voltage hysteresis of the three-dimensional carbon fiber skeleton film-assisted zinc foil is approximately 37 mV. Bare zinc foil exhibits the highest voltage hysteresis, approximately 66 mV. After 1200 hours, the three-dimensional carbon fiber skeleton film@copper-assisted zinc foil maintains a voltage hysteresis of 52 mV, still lower than the initial voltage hysteresis of the bare zinc foil. The cycle life of the above-mentioned three-dimensional carbon fiber skeleton film@copper-assisted zinc foil is superior to that of the multifunctional ferroelectric polymer protected zinc electrode in the invention patent application with publication number CN116364838A at 0.5 mA cm⁻¹. -2 and area capacity 0.5mAh cm -2 The 750h is superior to the ZnSe@Zn symmetric cell in the invention patent application with publication number CN115799512A at 1mAcm. -2 and 1mAh cm -2 The cycle life is 650 hours, which is superior to the zinc anode modified with oxygen-rich materials in the invention patent application with publication number CN115312704A at 3 mA / cm². -2 and 1mAh cm -2Its cycle life is 550h, which is better than the 500h of the invention patent application with publication number CN113488607A.

[0040] Figure 7 Three-dimensional carbon fiber skeleton film@copper-assisted zinc foil, three-dimensional carbon fiber skeleton film-assisted zinc foil, bare zinc foil at a current density of 2 mA / cm² -2 The nucleation overpotential diagram shows that the nucleation overpotential of the 3D carbon fiber skeleton film@copper-assisted zinc foil (41.5 mV) is lower than that of bare zinc foil (72.2 mV) and 3D carbon fiber skeleton film-assisted zinc foil (65.6 mV). The smaller the nucleation overpotential, the lower the nucleation energy barrier.

[0041] Figure 8 Three-dimensional carbon fiber skeleton film@copper-assisted zinc foil, three-dimensional carbon fiber skeleton film-assisted zinc foil, bare zinc foil at a scanning rate of 1 mV / s -1 The Tafel curves show that the corrosion current (Icorr) of the three-dimensional carbon fiber skeleton film @ copper-assisted zinc foil is 1.16 × 10⁻⁶. 3 A cm -2 The value is lower than that of zinc foil assisted by three-dimensional carbon fiber skeleton film, which is 1.91 × 10⁻⁶. 3 Acm -2 And bare zinc 3.71×10 3 Acm -2 The corrosion potential (Ecorr) of the 3D carbon fiber skeleton film@copper-assisted zinc foil is -0.025V, slightly higher than that of the 3D carbon fiber skeleton film-assisted zinc foil (-0.0264V) and bare zinc (-0.0281V). The lower corrosion current and more positive corrosion potential indicate that the auxiliary anolyte 3D carbon fiber skeleton film@copper can protect the Zn foil from corrosion.

[0042] Figure 9 Three-dimensional carbon fiber skeleton film @ copper-assisted zinc foil, three-dimensional carbon fiber skeleton film assisted zinc foil, bare zinc foil at 1 mA cm -2 and 1mAh cm -2 The coulombic efficiency plots show that the 3D carbon fiber skeleton membrane@copper asymmetric cell exhibits highly reversible deposition / stripping behavior, achieving a coulombic efficiency of 99.5% after 600 cycles without any degradation. In contrast, the 3D carbon fiber skeleton membrane-assisted asymmetric cell and the bare zinc asymmetric cell failed after 200 and 120 cycles, respectively, with coulombic efficiencies of only 98.9% and 91.2%. The high coulombic efficiency indicates that the 3D carbon fiber skeleton membrane@copper, as an auxiliary anode, can suppress side reactions.

[0043] Figure 10 Three-dimensional carbon fiber skeleton film @ copper-assisted zinc foil at 10 mA cm -2 and 2mAh cm -2The surface SEM image after 250 charge-discharge cycles shows that the zinc deposits on the zinc foil are fine and flat, without large grains or sharp protrusions, indicating that the three-dimensional carbon fiber skeleton film@copper alters the growth pattern of zinc deposits and inhibits the growth of zinc dendrites.

[0044] Figure 11 Three-dimensional carbon fiber skeleton film@copper-assisted zinc foil with a current of 10 mA / cm -2 Deposition 10mAh cm -2 The cross-sectional SEM image shows that the carbon fibers at the bottom of the carbon fiber skeleton film@copper are coarse, irregular and angular due to zinc deposition, which is significantly different from the smooth and delicate carbon fibers at the top. This indicates that zinc is deposited in the lower part of the three-dimensional carbon fiber skeleton film@copper, but not in the top.

[0045] Furthermore, it should be understood that after reading the above description of the present invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. The application of a copper nanoparticle gradient-modified three-dimensional carbon fiber framework membrane in an aqueous zinc metal battery, the aqueous zinc metal battery comprising a separator and zinc foil as the anode, characterized in that, The preparation method of the copper nanoparticle gradient-modified three-dimensional carbon fiber skeleton membrane includes: uniformly dropping a copper acetate solution onto a flat filter paper, allowing the copper acetate solution to penetrate into the filter paper from top to bottom. During the penetration process, the copper acetate dissolved in the solution is adsorbed by the filter paper, and the copper acetate content in the filter paper decreases gradually from top to bottom; after the filter paper with the gradient adsorption of copper acetate is dried, it is heat-treated at 300-400℃ in a hydrogen-argon mixed atmosphere to obtain the copper nanoparticle gradient-modified three-dimensional carbon fiber skeleton membrane. The copper nanoparticle gradient-modified three-dimensional carbon fiber skeleton film is placed between the zinc foil and the separator as an auxiliary anode, with the copper-rich side of the copper nanoparticle gradient-modified three-dimensional carbon fiber skeleton film close to the zinc foil and the copper-poor side close to the separator.

2. The application according to claim 1, characterized in that, In the method for preparing the copper nanoparticle gradient-modified three-dimensional carbon fiber skeleton membrane, the filter paper is made of cotton fiber.

3. The application according to claim 2, characterized in that, After heat treatment at 300-400℃, the surface layer of cotton fibers decomposes into carbon, while the core of the fibers remains cotton.

4. The application according to claim 1, characterized in that, The copper nanoparticles in the three-dimensional carbon fiber skeleton film modified with copper nanoparticle gradient have a particle size of 1–50 nm.

5. The application according to claim 1, characterized in that, In the method for preparing the three-dimensional carbon fiber skeleton film modified by copper nanoparticle gradient, the concentration of the copper acetate solution is 1-40 g / L.

6. The application according to claim 5, characterized in that, In the preparation method of the copper nanoparticle gradient-modified three-dimensional carbon fiber framework film, the amount of copper acetate solution used is 0.3-0.4 mL / cm³. 2 Filter paper meter.

7. The application according to claim 6, characterized in that, In the preparation method of the three-dimensional carbon fiber skeleton membrane modified by copper nanoparticle gradient, the filter paper is immersed in the copper acetate solution for 5.5 to 6.5 hours.

8. The application according to claim 1, characterized in that, In the preparation method of the copper nanoparticle gradient modified three-dimensional carbon fiber skeleton film, the drying temperature is 55-65℃ and the drying time is 1.5-2.5h.

9. The application according to claim 1, characterized in that, In the method for preparing the copper nanoparticle gradient-modified three-dimensional carbon fiber skeleton film, the heating rate of the heat treatment is 4-6 °C / min.

10. The application according to claim 1, characterized in that, In the preparation method of the copper nanoparticle gradient modified three-dimensional carbon fiber skeleton film, the holding time at 300-400℃ is 1.5-2.5h.

Images