CN114664572A

CN114664572A - Synthesis method for simultaneously preparing high-performance supercapacitor positive electrode material and high-performance supercapacitor negative electrode material by taking Co-MOF array as precursor

Info

Publication number: CN114664572A
Application number: CN202210242207.4A
Authority: CN
Inventors: 肖振宇; 卜冉冉; 周凤鸣; 迟锦耀; 王磊
Original assignee: Qingdao University of Science and Technology
Current assignee: Qingdao University of Science and Technology
Priority date: 2022-03-11
Filing date: 2022-03-11
Publication date: 2022-06-24

Abstract

A synthetic method for simultaneously preparing high-performance super capacitor positive and negative electrode materials by taking a Co-MOF array as a precursor comprises the steps of firstly, mixing Ni (NO) with the molar ratio of 1 (3-9)₃)₂·6H₂Dissolving O and 2-MI in water respectively, and vertically immersing 1 x 1cm of foamed Nickel (NF) or foamed iron nickel (FNF) to obtain Co-MOF @ NF and Co-MOF @ FNF. Co-MOF @ NF was then soaked to 76mg Ni (NO)₃)₂Preparing CN-LDH by using the ethanol solution, and immersing the CN-LDH into the solution containing 1-12 mmol of L^‑1NaVO (NaVO)₃Standing in the aqueous solution to obtain CNV; soaking Co-MOF @ FNF into 1-6 mg mL^‑1Fe(NO₃)₃·9H₂Obtaining CF-LDH by O aqueous solution, and immersing the array in a solution containing 1-12 mmol L^‑1NaVO (NaVO)₃And standing in the aqueous solution to obtain CFV. Immersing CNV or CFV into a solution containing 2.5mg mL^‑1～10mg mL^‑1The reaction was carried out at 160 ℃ for 12 hours to obtain CNVS-x or CFVS (x ═ TAA solution concentration/2.5) as the target product. The preparation strategy for constructing two trimetal sulfide composite materials based on the same Co-MOF precursor provided by the invention improves the electron transfer rate and enhances the energy density of a super capacitor.

Description

Synthesis method for simultaneously preparing high-performance supercapacitor positive electrode material and high-performance supercapacitor negative electrode material by taking Co-MOF array as precursor

Technical Field

The invention belongs to the technical field of functional nano composite materials, and particularly relates to a synthetic method for simultaneously preparing two trimetal sulfide composite materials by taking a Co-metal organic framework material as a precursor and an electrochemical energy storage application thereof.

Background

The super capacitor is an electrochemical energy storage device widely applied to hybrid electric vehicles, smart grids and flexible electronic devices, and has attracted more and more attention due to high power density, long service life, environmental friendliness and good safety. Although supercapacitors have ultra-high power densities and can complete a complete charge-discharge cycle within seconds, the energy density of supercapacitors is really poor, typically less than 30Wh kg^-1And further popularization and large-scale application of the composite material are limited. The electrode material is the core of the super capacitor, so how to design the high-performance positive and negative electrodes of the super capacitor, and the preparation of the hybrid super capacitor device is an effective strategy for improving the energy density of the super capacitor device.

The Metal-organic frameworks (MOFs) are porous three-dimensional network materials formed by organic ligands and inorganic ions or clusters through coordination bonds, and have the advantages of composition, appearance and structural diversity, high specific surface area, abundant and adjustable pore structures, high-dispersion Metal centers and the like, so the Metal-organic frameworks (MOFs) are considered to be ideal precursors for preparing electrode materials of supercapacitors. In recent years, the preparation of MOFs-derived electrode materials based on ion exchange or liquid etching strategies, exploiting the reversibility of coordination bonds, has attracted the attention of countless researchers. In the MOFs etching process, the organic ligand is replaced by inorganic ions and small molecules to form free coordination anions, the inorganic anions and the released organic ligand can migrate in and out of the material, so that more channels are provided for ion migration, and excellent supercapacitor performance is realized. As the MOFs etching process is an ion exchange process which is carried out thermodynamically and spontaneously, the process can be completed at a lower reaction temperature, so that the ion exchange method has the characteristics of higher controllability, higher simplicity and higher energy saving, and can be used as a new way for preparing high-performance anode and cathode battery materials.

Transition Metal Sulfides (TMSs), e.g. Co₉S₈、Ni₃S₂And FeS₂And the like, are ideal pseudocapacitor/battery type electrode materials due to rapid oxidation-reduction activity, high-capacity storage and cycling stability. It is reported that the TMSs are doped with high-valence elements, such as Mo, W, V and the like, not only can generate a large number of defect sites and provide more electroactive centers, but also can form a heterostructure and provide rich channels and pore structures, thereby facilitating the rapid diffusion of ions and improving the redox kinetics. Therefore, the design and regulation of high-valence element doping of the TMSs and the optimization of the structure, the form and the composition of a product are effective strategies for constructing high-performance electrode materials.

Disclosure of Invention

The invention provides a strategy combining two-step etching and one-step vulcanization, which introduces cations (Ni) into Co-MOF in sequence²⁺/Fe³⁺) And anions (VO)₃ ^-) So as to realize the co-doping of anions and cations; meanwhile, the prepared trimetal heterogeneous sulfide not only maintains the parent framework of Co-MOF, but also has high specific surface area and rich pore structure through an accurate controllable vulcanization process. The prepared electrode material can be respectively used as a positive electrode and a negative electrode of a super capacitor, and has ultrahigh specific capacity and excellent cycling stability.

In order to construct a super capacitor device with high energy density, the invention constructs the positive electrode material and the negative electrode material of a high-performance super capacitor through a strategy of combining etching and vulcanization based on a Co-MOF precursor. The synthesis of the electrode material can be realized by the following technical route:

1. a synthetic method for simultaneously preparing a high-performance supercapacitor positive electrode material and a high-performance supercapacitor negative electrode material by taking a Co-MOF array as a precursor comprises the following steps:

(1) preparation of Co-MOF precursor: cobalt nitrate hexahydrate (Ni (NO) with a certain molar ratio (1 (3-9)) is added₃)₂·6H₂O) and dimethylimidazole (2-MI) are respectively dissolved in deionized water, and then the two are mixedMixing the seed solutions, vertically immersing a piece of 1 x 1cm of foamed Nickel (NF) or foamed iron-nickel (FNF) into the solution, and standing at room temperature for 1-18h to obtain Co-MOF @ NF growing on a foamed nickel current collector and Co-MOF @ FNF growing on the foamed iron-nickel current collector.

(2) Preparation of basic Cobalt Nickel Vanadate (CNV): firstly, soaking the Co-MOF array prepared in the step (1) into a mixture containing 76mg of Ni (NO)₃)₂Preparing Co-MOF (CN-LDH) coated with a Co/Ni-LDH shell layer in 25mL of ethanol solution for 1-16 h; further immersing the array in a solution containing 1 to 12mmol of L^-1NaVO (NaVO)₃And (3) stirring the aqueous solution at room temperature for 1-3 hours, and etching the internal Co-MOF nuclei to obtain the basic cobalt nickel vanadate CNV.

(3) Preparation of basic cobalt iron vanadate (CFV): firstly, soaking the Co-MOF precursor growing on the foam iron-nickel prepared in the step (1) into 1-6 mg mL^-1Fe(NO₃)₃·9H₂Obtaining Co-MOF (CF-LDH) coated with a Co/Fe-LDH shell layer in an O aqueous solution for 1-10 min; further immersing the array in a solution containing 1 to 12mmol of L^-1NaVO (NaVO)₃And (3) stirring the aqueous solution at room temperature for 1-3 hours, and etching the internal Co-MOF nuclei to obtain the basic cobaltous vanadate iron CFV.

(4) Ni/V-doped Co₃S₄And Co/Ni-doped VS₂Heterostructure (CNVS) and Fe/V-doped Co₃S₄And Co/Fe-doped VS₂Preparation of heterostructure (CFVS): immersing CNV or CFV in a solution containing 2.5mg mL^-1～10mg mL^-1In 3mL of Thioacetamide (TAA) solution at 160 ℃ for 12 hours to obtain the target product CNVS-x or CFVS (where x is the concentration of TAA solution/2.5).

The method of claim 1, wherein: the step (1) cobalt nitrate hexahydrate (Ni (NO)₃)₂·6H₂O) and dimethylimidazole (2-MI) in a molar ratio of 1: 8; standing for 2 hours at room temperature to synthesize Co-MOF with uniform appearance and size.

The method of claim 1, wherein: the step (2) is carried out on Ni (NO)₃)₂Soaking in ethanol solution10h to ensure that there is sufficient Ni source in CN-LDH for step (3); NaVO₃The optimum concentration of the aqueous solution is 6mmol L^-1And stirring for 2 hours at room temperature to realize the sufficient etching of the Co-MOF core.

The method of claim 1, wherein: said step (3) Fe (NO)₃)₃·9H₂The optimum concentration of O solution is 4mg ml^-1The optimal time for Co/Fe-LDH coating is 5min to reduce Fe (NO)₃)₃·9H₂Disruption of Co-MOF array structure by O.

The method of claim 1, wherein: the optimal concentration of the TAA in the step (4) is 7.5mg mL^-1To form Co₃S₄And VS₂A heterostructure.

The method of claim 1, wherein: the CNVS prepared in the step (4) can be used as a super capacitor anode material, and the CFVS prepared can be used as a super capacitor cathode material.

As a further feature of the invention: the two trimetal sulfide electrode materials (CNVS/CFVS) constructed based on the same Co-MOF precursor obtained in the step (4) are respectively used as positive and negative electrode materials of the hybrid supercapacitor, and have excellent electrochemical performance. When the test is carried out under a three-electrode system, the voltage range of 0-0.5V and the voltage range of 2mA cm^-2The specific capacity of CNVS-x is 4096-6556 mF cm^-2Wherein the capacity retention rate of the optimal sample CNVS-3 reaches 85% after 3000 cycles; CFVS voltage interval of-1.1- (-0.1V) and 5mA cm^-2The specific capacity is up to 6195mF cm^-2。

By way of further features of the invention: the two trimetal sulfide electrode materials (CNVS/CFVS) constructed based on the same Co-MOF precursor and obtained in the step (4) are respectively used as positive and negative electrode materials of the hybrid super capacitor to assemble and construct a two-electrode hybrid super capacitor, and the thickness of the two-electrode hybrid super capacitor is 0.4mW cm^-2Under the power density, the energy density is as high as 0.73mW h cm^-2。

Due to the adoption of the technical scheme, the invention has the following beneficial effects:

the principle of the prepared leaf-shaped trimetal sulfide constructed based on the same Co-MOF precursor is that the in-situ substitution reaction of ions is realized based on the reversibility of coordination bonds. For Co/M-LDH coating process (M ═ Ni)²⁺/Fe³⁺)，Ni²⁺(Fe³⁺) Hydrolysis of the ions produces Ni (Fe) -LDH crystallites and H⁺Ion, H⁺The ions further attack the Co-MOF, releasing Co²⁺Ion, Co²⁺The ions are further coprecipitated with M-LDH (M ═ Ni or Fe) microcrystals on the surface of the triangular flaky Co-MOF to form the core-shell structure Co-MOF @ M-LDH. Due to Fe³⁺Ion ratio of Ni²⁺The ions have stronger hydrolytic capability, and the etching reaction of Co-MOF is from H⁺Ion-driven, so the Co/Fe-LDH coating time is shorter than that of Co/Ni-LDH. For NaVO₃Etching process by NaVO₃The hydrolysis process of (2) produces a large amount of OH^-Anion, OH^-And 2-MeIM^-Further etching the Co-MOF core in the Co-MOF @ ni (fe) -LDH, thereby introducing the V element to form the CNV. Finally, transferring the tri-metal Co-doped hollow Co/M/V-LDH nanosheet array to a layered Co/M/V-S array (M ═ Ni or Fe), Ni/V-or Fe/V-doped Co₃S₂Nanoparticles randomly distributed in Co/Ni-or Co/Fe-doped VS₂An out-phase interface is formed on the nano plate, so that the transfer rate of electrons and electrolyte in reaction kinetics is rapidly improved, more electrically active sites are provided for deep oxidation-reduction reaction, and the specific capacity and energy density of the super capacitor are enhanced. Therefore, the method for preparing the three-metal sulfide with the same Co-MOF precursor to construct two leaf-shaped three-metal sulfides has excellent electrochemical performance. Specifically, CNVS-x at 2mA cm^-2The specific capacity of the alloy reaches 4096-6556F g under the current density^-1Where the optimal sample CNVS-3 cycles 3000 maintains 85% of the initial capacity: CFVS voltage interval of-1.1- (-0.1V) and 5mA cm^-2The specific capacity is up to 6195mF cm^-2。

Detailed Description

The technical features of the present invention will be described below with reference to specific experimental schemes and drawings, but the present invention is not limited thereto. The test methods described in the following examples are all conventional methods unless otherwise specified; the apparatus and materials are commercially available, unless otherwise specified.

Example 1

A synthetic method for simultaneously preparing high-performance supercapacitor positive and negative electrode materials by taking a Co-MOF array as a precursor comprises the following steps:

(1) cobalt nitrate hexahydrate (Ni (NO) with a molar ratio of 1:8₃)₂·6H₂O) and dimethylimidazole (2-MI) are respectively dissolved in deionized water, then the two solutions are mixed, a piece of Nickel Foam (NF) or nickel iron foam (FNF) with the thickness of 1 x 1cm is vertically immersed in the solution, and the solution is kept stand for 2 hours at room temperature to obtain Co-MOF @ NF growing on a nickel foam current collector and Co-MOF @ FNF growing on the nickel foam current collector. The morphology of Co-MOF @ NF is shown in a scanning electron micrograph (figure 1); the crystallinity of Co-MOF @ NF is shown by its powder X-ray diffraction pattern (FIG. 2); the morphology of the Co-MOF @ FNF is shown in a scanning electron micrograph (figure 3); the crystallinity of Co-MOF @ FNF is shown by its powder X-ray diffraction pattern (FIG. 4).

(2) The Co-MOF @ NF array prepared in the previous step was soaked to contain 76mg Ni (NO)₃)₂Preparing Co-MOF (CN-LDH) coated with a Co/Ni-LDH shell layer in 25mL of ethanol solution for 10h, wherein the morphology of the CN-LDH is shown by a scanning electron microscope (figure 5); the array was further immersed in a solution containing 6mmol L^-1NaVO (NaVO)₃And (3) stirring the aqueous solution at room temperature for 2 hours to prepare the target product basic cobalt nickel vanadate CNV. The morphology of the CNV is shown by its scanning electron microscope (fig. 6).

(3) Soaking the Co-MOF @ FNF precursor in the step (1) to 4mg mL^-1Fe(NO₃)₃·9H₂Obtaining Co-MOF (CF-LDH) coated with a Co/Fe-LDH shell layer in an O aqueous solution for 5min, wherein the appearance of the CF-LDH is shown by a scanning electron microscope (figure 7); the array was further immersed in a solution containing 6mmol L^-1NaVO (NaVO)₃Stirring the aqueous solution for 2 hours at room temperature, and etching internal Co-MOF nuclei to obtain a target product, namely basic cobalt vanadateThe morphology of the iron CFV, is shown by its scanning electron microscope (fig. 8).

(4) Immersing CNV or CFV prepared in the previous step into a solution containing 7.5mg mL^-1To 3mL Thioacetamide (TAA) solution at 160 deg.C for 12 hours to obtain the desired product CNVS-3 or CFVS. The crystallinity of CNVS-3 is shown by its powder X-ray diffraction pattern (FIG. 9); the morphology of CNVS-3 is shown in a scanning electron microscope picture (figure 10), the material maintains the triangular flake-shaped morphology of the precursor, and the surface is composed of a plurality of ultra-small nano particles; the microscopic morphology of CNVS-3 is shown in a transmission electron microscope picture (figure 11), and the material consists of nano-particles wrapped by nano-sheets; the electron spectrum of CNVS-3 is shown in XPS (FIG. 12), the material contains Co, Ni, V, S, O and other elements, which indicates that Ni, V and S are successfully introduced into the derivative material. Constant-current charging and discharging of CNVS-3 at different sweep rates is shown in FIG. 13, and CNVS-3 at 2mA cm is calculated from the graph^-2The specific capacity of the alloy reaches 6556mF cm ^-23000 cycles maintain 85% of the initial capacity (fig. 14); the morphology of CFVS is shown in a scanning electron microscope image (figure 15), the material maintains the triangular sheet-shaped morphology of the precursor, the surface has a small number of pore structures, and the microscopic morphology of CFVS-3 is shown in a transmission electron microscope image (figure 16); the electron spectrum of CFVS is shown in XPS (FIG. 17), the material contains Co, Fe, V, S, O and other elements, and Fe, V and S are successfully introduced into the derivative material. Constant-current charging and discharging of CFVS at different sweep rates is shown in FIG. 18, and CFVS at 5mA cm is calculated in the graph^-2The specific capacity of the alloy reaches 6195mF cm under the current density^-2Cycle 1000 maintains 82.9% of the original capacity (fig. 19).

Example 2

The method comprises the following steps:

(1) the Co-MOF @ NF and Co-MOF @ FNF precursors were prepared as in example 1.

(2) CN-LDH was prepared as in example 1, and this procedure did not require NaVO treatment of CN-LDH₃And (5) etching treatment.

(3) The CFV was prepared as in example 1.

(4) The resulting CN-LDH was directly immersed in a vertical solution containing 7.5mg mL^-1In 3mL Thioacetamide (TAA) solution at 160 ℃ for 12 hours to prepare CNS material. Constant current charge and discharge of CNS at different sweep rates is shown in FIG. 20, which is calculated to be 2mA cm for CNS^-2The specific capacity of the current density of the battery reaches 3252mF cm^-2. CFVS was prepared as in example 1.

Example 3

(1) the Co-MOF precursor was prepared as in example 1.

(2) CNV was prepared as in example 1.

(3) The CFV was prepared as in example 1.

(4) The resulting CNV was immersed vertically in a solution containing 2.5mg mL^-1In 3mL of Thioacetamide (TAA), at 160 ℃ for 12 hours. Obtaining the CNVS-1 material. Constant-current charging and discharging of CNVS-1 at different sweep rates is shown in FIG. 21, and CNVS-1 at 2mA cm is calculated from the graph^-2The specific capacity of the current density of the alloy reaches 4096mF cm^-2. CFVS was made as in example 1.

Example 4

(1) the preparation of the Co-MOF precursor was the same as in example 1.

(2) CNV was prepared as in example 1.

(3) The CFV was prepared as in example 1.

(4) The resulting CNV was vertically immersed in a solution containing 5mg mL^-1In 3mL of Thioacetamide (TAA), and reacted at 160 ℃ for 12 hours. Obtaining the CNVS-2 material. Constant-current charging and discharging of CNVS-2 at different sweep rates is shown in FIG. 22, and CNVS-2 at 2mA cm is calculated from the graph^-2The specific capacity of the current density reaches 4920mF cm^-2. CFVS was prepared as in example 1.

Example 5

(1) the Co-MOF precursor was prepared as in example 1.

(2) CNV was prepared as in example 1.

(3) The CFV was prepared as in example 1.

(4) The resulting CNV was vertically immersed in a solution containing 10mg mL^-1In 3mL of Thioacetamide (TAA), and reacted at 160 ℃ for 12 hours. Obtaining the CNVS-4 material. Constant-current charging and discharging of CNVS-4 at different sweep rates is shown in FIG. 23, and CNVS-4 at 2mA cm is calculated from the graph^-2Has a specific capacity of 5076mF cm^-2. CFVS was prepared as in example 1.

The description of the disclosed embodiments is not intended to limit the scope of the invention, but is instead provided to describe the invention. Accordingly, the scope of the present invention is not limited by the above embodiments, but is defined by the claims or their equivalents.

Description of the drawings:

FIG. 1: scanning electron micrographs of Co-MOF @ NF obtained in example 1;

FIG. 2: the X-ray diffraction pattern of Co-MOF @ NF obtained in example 1;

FIG. 3: scanning electron micrographs of Co-MOF @ FNF obtained in example 1;

FIG. 4: the X-ray diffraction pattern of Co-MOF @ FNF obtained in example 1;

FIG. 5 is a schematic view of: scanning electron micrograph of CN-LDH obtained in example 1;

FIG. 6: scanning electron micrographs of CNVs obtained in example 1;

FIG. 7: scanning electron micrograph of CF-LDH obtained in example 1;

FIG. 8: scanning electron micrographs of the CFV obtained in example 1;

FIG. 9: the X-ray diffraction pattern of CNVS-3 obtained in example 1;

FIG. 10: scanning electron microscopy of the CNVS-3 obtained in example 1;

FIG. 11: transmission electron microscopy of CNVS-3 obtained in example 1;

FIG. 12: an X-ray photoelectron spectrum of CNVS-3 obtained in example 1;

FIG. 13: a constant current charge-discharge diagram of the CNVS-3 obtained in the example 1 under different current densities;

FIG. 14: a cycle stability test graph of the CNVS-3 obtained in the example 1 in a three-electrode system;

FIG. 15 is a schematic view of: scanning electron micrographs of CFVS obtained in example 1;

FIG. 16: transmission electron microscopy of CFVS obtained in example 1;

FIG. 17: an X-ray photoelectron spectrum of CFVS obtained in example 1;

FIG. 18: a constant current charge-discharge diagram of CFVS obtained in example 1 at different current densities;

FIG. 19: a cycle stability test graph of CFVS in a three-electrode system obtained in example 1;

FIG. 20: constant current charge-discharge plots of the CNS obtained in example 2 at different current densities;

FIG. 21: a constant current charge-discharge diagram of the CNVS-1 obtained in example 3 at different current densities;

FIG. 22: a constant current charge-discharge diagram of the CNVS-2 obtained in example 4 at different current densities;

FIG. 23: constant current charge and discharge plots of CNVS-4 obtained in example 5 at different current densities.

Claims

1. A synthetic method for simultaneously preparing high-performance supercapacitor positive and negative electrode materials by taking a Co-MOF array as a precursor comprises the following steps:

(1) preparation of Co-MOF precursor: cobalt nitrate hexahydrate (Ni (NO) with a certain molar ratio (1 (3-9)) is added₃)₂·6H₂O) and dimethyl imidazole (2-MI) are respectively dissolved in deionized water, then the two solutions are mixed, a piece of 1 x 1cm of foam Nickel (NF) or foam iron (FNF) is vertically immersed in the solution, and the solution is kept stand for 1 to 18 hours at room temperature to obtain the foam nickel afflux flow growing on the foam nickel afflux flowCo-MOF @ NF on the bulk and Co-MOF @ FNF grown on a foamed iron-nickel current collector.

(2) Preparation of basic Cobalt Nickel Vanadate (CNV): firstly, soaking the Co-MOF array prepared in the step (1) into Ni (NO)₃)₂Preparing Co-MOF (CN-LDH) coated with a Co/Ni-LDH shell layer in the ethanol solution for 1-16 h; further immersing the array in a solution containing 1 to 12mmol of L^-1NaVO (NaVO)₃And (3) stirring the aqueous solution at room temperature for 1-3 hours, and etching the internal Co-MOF nuclei to obtain the basic cobalt nickel vanadate CNV.

(3) Preparation of basic cobalt iron vanadate (CFV): firstly, soaking the Co-MOF precursor growing on the foam iron-nickel prepared in the step (1) into 1-6 mg mL^-1Fe(NO₃)₃·9H₂Obtaining Co-MOF (CF-LDH) coated with a Co/Fe-LDH shell layer in an O aqueous solution for 1-10 min; further immersing the array in a solution containing 1 to 12mmol of L^-1NaVO (NaVO)₃And (3) stirring the aqueous solution at room temperature for 1-3 hours, and etching the internal Co-MOF nuclei to obtain basic cobalt ferric vanadate CFV.

(4) Ni/V-doped Co₃S₄And Co/Ni-doped VS₂Heterostructure (CNVS) and Fe/V-doped Co₃S₄And Co/Fe-doped VS₂Preparation of heterostructure (CFVS): immersing CNV or CFV into a solution containing 2.5mg mL^-1～10mg mL^-1In 3mL Thioacetamide (TAA) solution at 160 deg.C for 12 hr to obtain the target product CNVS or CFVS.

2. The method of claim 1, wherein: the step (1) cobalt nitrate hexahydrate (Ni (NO)₃)₂·6H₂O) and dimethylimidazole (2-MI) in a molar ratio of 1: 8; standing for 2 hours at room temperature to synthesize Co-MOF with uniform appearance and size.

3. The method of claim 1, wherein: the step (2) is carried out on Ni (NO)₃)₂Soaking in an ethanol solution for 10h, and using enough Ni source in CN-LDH for the step (3); NaVO₃The optimum concentration of the aqueous solution is 6mmol L^-1And stirring for 2 hours at room temperature to realize the sufficient etching of the Co-MOF core.

4. The method of claim 1, wherein: said step (3) Fe (NO)₃)₃·9H₂The optimum concentration of O solution is 4mg ml^-1The optimal time for Co/Fe-LDH coating is 5min to reduce Fe (NO)₃)₃·9H₂Disruption of Co-MOF array structure by O.

5. The method of claim 1, wherein: the optimal concentration of the TAA in the step (4) is 7.5mg mL^-1To form Co₃S₄And VS₂A heterostructure.

6. The method of claim 1, wherein: the CNVS prepared in the step (4) can be used as a super capacitor anode material, and the CFVS prepared can be used as a super capacitor cathode material.