CN115074792B - Preparation method of cobalt-based alloy film with special structure and product - Google Patents

Abstract

The invention discloses a preparation method and product of a cobalt-based alloy film layer with a special structure, and belongs to the technical field of metal materials. The preparation method of the cobalt-based alloy film layer includes the following steps: immersing the metal base material in an acidic composite plating solution for composite electrodeposition, and then immersing it in an alkaline solution for immersion corrosion to obtain the cobalt-based alloy film layer; the acidic The preparation of the composite plating solution includes: adding cobalt salt, tungsten salt and Al ₂ O ₃ particles into a solvent, mixing, and then adjusting the pH value to acidic to obtain the acidic composite plating solution. The cobalt-based alloy film layer has improved wear resistance, reduced hydrogen evolution overpotential, improved hydrogen evolution performance, and has excellent catalytic performance.

Description

Preparation method and product of a special structure cobalt-based alloy film layer

Technical field

The invention relates to the technical field of metal materials, and in particular to a preparation method and product of a special structure cobalt-based alloy film layer.

Background technique

Among many clean energy sources, hydrogen energy, as an economical, efficient and sustainable green energy, is one of the most ideal energy carriers and has received more and more widespread attention. Among various hydrogen production technologies, water electrolysis to produce hydrogen is considered to be one of the most effective ways to lead to the "hydrogen economy". However, in practical applications, water electrolysis to produce hydrogen often needs to overcome a high hydrogen evolution overpotential, resulting in high energy losses. In order to effectively solve the technical bottleneck of water electrolysis and hydrogen evolution overpotential being too high, the application of high-efficiency catalytic materials is The technical key to breaking through this bottleneck. At present, the precious metal platinum and its alloys are the most effective hydrogen evolution catalysts, but shortcomings such as high price, scarce resources, and poor electrochemical stability limit their large-scale application. Powdered catalysts are limited by binders and electrochemical stability. Therefore, there is an urgent need to develop a non-noble metal electrode material with high mechanical strength and good catalytic activity.

Among many non-noble metal electrocatalytic materials, transition metal phosphide is one of the hydrogen evolution electrocatalytic materials with high catalytic activity, good stability and good cost-effectiveness due to its unique electronic structure and metal-like properties. It has the ability to replace Pt-based potential of electrocatalytic materials. At present, most of the phosphide catalytic materials used for hydrogen separation in water electrolysis are prepared by solution hydrothermal synthesis process and high-temperature solid-phase reduction process. Most of them are in the form of powder, which needs to be fully dispersed in the solvent, and then Nafion solution and polyvinylidene fluoride are used. Binders such as organic solutions are used to fix it on the conductive carrier, so that the catalyst loading capacity of the catalytic electrode is limited, and the binder will reduce the electrical conductivity of the electrode material, and there are also parts where the binder will coat and shield the catalyst. The active sites reduce its catalytic performance; in addition, during the long-term electrolysis process, the active catalytic material easily falls off the electrode surface, resulting in poor stability of the catalytic electrode for hydrogen separation in water electrolysis. How to prepare a non-noble metal electrode material with good catalytic activity and wear resistance has become an urgent technical problem for those skilled in the art to be solved.

Contents of the invention

The purpose of the present invention is to provide a method and product for preparing a cobalt-based alloy film layer with a special structure to solve the problems existing in the prior art. The present invention prepares a composite electrode composed of cobalt, tungsten and Al ₂ O ₃ particles on the surface of the base material. Deposition, and then etching the Al ₂ O ₃ particles with NaOH solution to form a special structure (comparing Figures 1 to 2 and Figure 8, you can see the special structure and the original structure. After the aluminum oxide particles are removed, the surface remains porous ) cobalt-based alloy film layer, which has both wear resistance and high hydrogen evolution performance.

In order to achieve the above objects, the present invention provides the following solutions

One of the technical solutions of the present invention:

The metal base material is immersed in an acidic composite plating solution for composite electrodeposition, and then immersed in an alkaline solution for immersion corrosion to obtain the cobalt-based alloy film layer;

The preparation of the acidic composite plating solution includes: adding cobalt salt, tungsten salt and Al ₂ O ₃ particles into a solvent, mixing, and then adjusting the pH value to acidity to obtain the acidic composite plating solution.

The Co-W alloy film layer has a dense structure, high hardness, good heat resistance, and excellent wear and corrosion resistance.

Removing alumina particles through corrosion can form a porous structure on the surface, effectively increasing the surface area and improving its electrocatalytic performance.

Further, the concentration of cobalt salt in the acidic composite plating solution is 0.05-0.1 mol/L, the concentration of tungsten salt is 0.05-0.1 mol/L, and the concentration of Al ₂ O ₃ particles is 10-30 g/L; The pH value of the acidic composite plating solution is 4.5 to 6.0.

The coating thickness of composite high-concentration alumina particles is lower than that of low-concentration coatings. Complexing agents can brighten, smooth and buffer.

Further, the cobalt salt is cobalt sulfate; the tungsten salt is sodium tungstate.

Further, the acidic composite plating solution also contains a complexing agent.

Further, the concentration of the complexing agent in the acidic composite plating solution is 0.2-0.4 mol/L; the complexing agent is diammonium hydrogen citrate.

Further, the conditions of the composite electrodeposition are: constant current density, current density is 10~50mA/cm ² , electrodeposition time is 30~60min, and electrodeposition temperature is 40~70°C.

Further, the alkaline solution includes NaOH solution; the concentration of the NaOH solution is 5-7 mol/L.

Further, the temperature of the immersion corrosion is 60-80°C.

The second technical solution of the present invention: a cobalt-based alloy film layer prepared by the above preparation method.

The third technical solution of the present invention: the application of the above-mentioned cobalt-based alloy film layer in the preparation of electrode materials.

The invention discloses the following technical effects:

(1) Using the acidic composite plating solution of the present invention to conduct composite electrodeposition on the base material, a Co-W alloy film layer with excellent mechanical properties can be formed, which is further immersed in a NaOH solution for corrosion, and finally a Co-W alloy film layer with a thickness of A 10-13μm special structure cobalt-based alloy film. The composite film has a smooth surface, a uniform special structure, and a friction coefficient of 0.5-0.8. When corroded at a current density of 10-100mA/ ^cm2 , its hydrogen evolution overpotential decreases (with Compared with 572mV of Co-W coating), the catalytic performance is improved.

(2) The specially structured cobalt-based alloy film prepared by the present invention has both wear resistance and high hydrogen evolution performance.

(3) On the basis of the existing composite co-deposition of cobalt salt and tungsten salt, the present invention adds Al ₂ O ₃ particles. The three substances are composite and co-deposited under the action of the complexing agent diammonium hydrogen citrate, which can be produced. The Co-W-Al ₂ O ₃ composite film layer is obtained, which can improve the wear resistance of the film layer. The Al ₂ O ₃ particles are then etched away in NaOH solution to obtain a cobalt-based alloy film with a special structure. The cobalt-based film layer itself has excellent performance, and the degranulation method used in the present invention prepares a cobalt-based alloy film layer with a special structure, so that the film layer has larger porosity, specific surface area and chemical activity, further improving the performance of the film layer. mechanical properties and catalytic properties. In addition, the present invention adopts composite electrodeposition and corrosion degranulation, and the obtained film layer has the advantages of wear resistance, large specific surface area (having a porous structure, the specific surface area becomes larger), and high hydrogen evolution performance.

(4) The method of the present invention is suitable for preparing various electrode materials in electrocatalysis (requiring excellent hydrogen evolution performance and wear resistance).

(5) The present invention adopts composite electrodeposition and corrosion degranulation technology to improve its hydrogen evolution performance and mechanical properties.

(6) The preparation method of the present invention is simple to operate, clean and environmentally friendly, suitable for metal materials with complex shapes and blind holes, and is easy to be industrialized.

Description of the drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the drawings needed to be used in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some of the drawings of the present invention. Embodiments, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without exerting creative efforts.

Figure 1 is a surface morphology diagram of the special structure cobalt-based alloy film layer prepared in Example 1 of the present invention;

Figure 2 is a surface morphology diagram of the special structure cobalt-based alloy film layer prepared in Example 2 of the present invention;

Figure 3 is a surface morphology diagram of the special structure cobalt-based alloy film prepared in Example 3 of the present invention;

Figure 4 is a surface morphology diagram of the special structure cobalt-based alloy film prepared in Example 4 of the present invention;

Figure 5 is a surface morphology diagram of the special structure cobalt-based alloy film layer prepared in Example 5 of the present invention;

Figure 6 is a surface morphology diagram of the special structure cobalt-based alloy film layer prepared in Example 6 of the present invention;

Figure 7 is a surface morphology diagram of the film layer prepared in Comparative Example 1 of the present invention;

Figure 8 is a surface morphology diagram of the film layer prepared in Comparative Example 2 of the present invention;

Figure 9 is a surface morphology diagram of the film layer prepared in Comparative Example 3 of the present invention;

Figure 10 is a surface morphology diagram of the film layer prepared in Comparative Example 4 of the present invention;

Figure 11 is a surface morphology diagram of the film layer prepared in Comparative Example 5 of the present invention.

Detailed ways

Various exemplary embodiments of the invention will now be described in detail. This detailed description should not be construed as limitations of the invention, but rather as a more detailed description of certain aspects, features and embodiments of the invention.

It should be understood that the terms used in the present invention are only used to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges in the present invention, it should be understood that every intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or value intermediate within a stated range and any other stated value or value intermediate within a stated range is also included within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded from the range.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only the preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and materials in connection with which they were cited. In the event of conflict with any incorporated document, the contents of this specification shall prevail.

It will be apparent to those skilled in the art that various modifications and changes can be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to the skilled person from the description of the invention. The specification and examples are intended to be illustrative only.

The words "includes", "includes", "has", "contains", etc. used in this article are all open terms, which mean including but not limited to.

Example 1

Preparation method of a special structure cobalt-based alloy film layer:

(1) Preparation of acidic composite plating solution: Add cobalt sulfate, sodium tungstate, complexing agent (diammonium hydrogen citrate), and alumina particles (particle size 1 μm) into the solvent water in sequence, mix, dissolve, and stir evenly to obtain acidic Composite plating solution.

The concentrations of each component are: cobalt sulfate 0.1 mol/L, sodium tungstate 0.1 mol/L, complexing agent (diammonium hydrogen citrate) 0.2 mol/L, and alumina particles 20 g/L. The temperature of the acidic composite plating solution is a constant temperature of 60°C, and the pH value is 5.0.

(2) Immerse the metal base material into the acidic composite plating solution for composite electrodeposition (composite electrodeposition is carried out under air stirring conditions, using a constant current density, the current density is 20mA/cm ² , the electrodeposition time is 60min, and the electrodeposition The temperature is 60℃), after the electrodeposition is completed, take it out, wash with water, and blow dry with cold air; then immerse it in a constant temperature (80℃) reactor containing NaOH solution (concentration: 5mol/L), and corrode for 60 minutes under air stirring to remove alumina. The particles are taken out, washed with water, and dried with cold air to obtain a special structure cobalt-based alloy film layer (base material with a composite film layer).

The prepared special structure cobalt-based alloy film layer was placed under a scanning electron microscope to observe its surface morphology. The results are shown in Figure 1. It can be seen from the figure that the surface of the obtained composite film layer is smooth and the special structure is uniform. After testing, the thickness of the obtained special structure cobalt-based alloy film is 13μm, the friction coefficient is 0.54, and when corroded at a current density of 10mA/ ^cm2 , its hydrogen evolution overpotential is 532mV, which is reduced compared with the 572mV of the Co-W coating. 40mV.

Example 2

Preparation method of a special structure cobalt-based alloy film layer:

(1) Preparation of acidic composite plating solution: Add cobalt sulfate, sodium tungstate, complexing agent (diammonium hydrogen citrate), and alumina particles (particle size 1 μm) into the solvent water in sequence, mix, dissolve, and stir evenly to obtain acidic Composite plating solution.

The concentrations of each component are: cobalt sulfate 0.1 mol/L, sodium tungstate 0.1 mol/L, complexing agent (diammonium hydrogen citrate) 0.2 mol/L, and alumina particles 10 g/L. The temperature of the acidic composite plating solution is a constant temperature of 60°C, and the pH value is 5.0.

(2) Immerse the metal base material into the acidic composite plating solution for composite electrodeposition (composite electrodeposition is carried out under air stirring conditions, using a constant current density, the current density is 20mA/cm ² , the electrodeposition time is 60min, and the electrodeposition The temperature is 60℃), after the electrodeposition is completed, take it out, wash with water, and blow dry with cold air; then immerse it in a constant temperature (80℃) reactor containing NaOH solution (concentration: 5mol/L), and corrode for 60 minutes under air stirring to remove alumina. The particles are taken out, washed with water, and dried with cold air to obtain a special structure cobalt-based alloy film layer (base material with a composite film layer).

The surface morphology of the prepared special structure cobalt-based alloy film layer was observed under a scanning electron microscope. The results are shown in Figure 2. It can be seen from the figure that the surface of the obtained composite film layer is smooth and the special structure is uniform. After testing, the thickness of the obtained special structure cobalt-based alloy film is 11μm, the friction coefficient is 0.53, and when corroded at a current density of 10mA/ ^cm2 , its hydrogen evolution overpotential is 567mV, which is reduced compared with the 572mV of the Co-W coating. 5mV.

Example 3

Preparation method of a special structure cobalt-based alloy film layer:

(1) Preparation of acidic composite plating solution: Add cobalt sulfate, sodium tungstate, complexing agent (diammonium hydrogen citrate), and alumina particles (particle size 1 μm) into the solvent water in sequence, mix, dissolve, and stir evenly to obtain acidic Composite plating solution.

The concentrations of each component are: cobalt sulfate 0.1 mol/L, sodium tungstate 0.1 mol/L, complexing agent (diammonium hydrogen citrate) 0.2 mol/L, and alumina particles 30 g/L. The temperature of the acidic composite plating solution is a constant temperature of 60°C, and the pH value is 5.0.

(2) Immerse the metal base material into the acidic composite plating solution for composite electrodeposition (composite electrodeposition is carried out under air stirring conditions, using a constant current density, the current density is 20mA/cm ² , the electrodeposition time is 60min, and the electrodeposition The temperature is 60℃), after the electrodeposition is completed, take it out, wash with water, and blow dry with cold air; then immerse it in a constant temperature (80℃) reactor containing NaOH solution (concentration: 5mol/L), and corrode for 60 minutes under air stirring to remove alumina. The particles are taken out, washed with water, and dried with cold air to obtain a special structure cobalt-based alloy film layer (base material with a composite film layer).

The prepared special structure cobalt-based alloy film layer was placed under a scanning electron microscope to observe its surface morphology. The results are shown in Figure 3. It can be seen from the figure that the surface of the obtained composite film layer is smooth and the special structure is uniform. After testing, the thickness of the obtained special structure cobalt-based alloy film is 10μm, the friction coefficient is 0.68, and when corroded at a current density of 10mA/ ^cm2 , its hydrogen evolution overpotential is 543mV, which is reduced compared with the 572mV of the Co-W coating. 29mV.

Example 4

Preparation method of a special structure cobalt-based alloy film layer:

(1) Preparation of acidic composite plating solution: Add cobalt sulfate, sodium tungstate, complexing agent (diammonium hydrogen citrate), and alumina particles (particle size 80nm) into the solvent water in sequence, mix, dissolve, and stir evenly to obtain acidic Composite plating solution.

The concentrations of each component are: cobalt sulfate 0.1 mol/L, sodium tungstate 0.1 mol/L, complexing agent (diammonium hydrogen citrate) 0.2 mol/L, and alumina particles 10 g/L. The temperature of the acidic composite plating solution is a constant temperature of 60°C, and the pH value is 5.0.

(2) Immerse the metal base material into the acidic composite plating solution for composite electrodeposition (composite electrodeposition is carried out under air stirring conditions, using a constant current density, the current density is 20mA/cm ² , the electrodeposition time is 60min, and the electrodeposition The temperature is 60℃), after the electrodeposition is completed, take it out, wash with water, and blow dry with cold air; then immerse it in a constant temperature (80℃) reactor containing NaOH solution (concentration: 5mol/L), and corrode for 60 minutes under air stirring to remove alumina. The particles are taken out, washed with water, and dried with cold air to obtain a special structure cobalt-based alloy film layer (base material with a composite film layer).

The prepared special structure cobalt-based alloy film layer was placed under a scanning electron microscope to observe its surface morphology. The results are shown in Figure 4. It can be seen from the figure that the surface of the obtained composite film layer is smooth and the special structure is uniform. After testing, the thickness of the obtained special structure cobalt-based alloy film is 12μm, the friction coefficient is 0.69, and when corroded at a current density of 10mA/ ^cm2 , its hydrogen evolution overpotential is 561mV, which is reduced compared with the 572mV of the Co-W coating. 11mV.

Example 5

Preparation method of a special structure cobalt-based alloy film layer:

(1) Preparation of acidic composite plating solution: Add cobalt sulfate, sodium tungstate, complexing agent (diammonium hydrogen citrate), and alumina particles (particle size 5 μm) into the solvent water in sequence, mix, dissolve, and stir evenly to obtain acidic Composite plating solution.

The concentrations of each component are: cobalt sulfate 0.1 mol/L, sodium tungstate 0.1 mol/L, complexing agent (diammonium hydrogen citrate) 0.2 mol/L, and alumina particles 20 g/L. The temperature of the acidic composite plating solution is a constant temperature of 60°C, and the pH value is 5.0.

(2) Immerse the metal base material into the acidic composite plating solution for composite electrodeposition (composite electrodeposition is carried out under air stirring conditions, using a constant current density, the current density is 20mA/cm ² , the electrodeposition time is 60min, and the electrodeposition The temperature is 60℃), after the electrodeposition is completed, take it out, wash with water, and blow dry with cold air; then immerse it in a constant temperature (80℃) reactor containing NaOH solution (concentration: 5mol/L), and corrode for 60 minutes under air stirring to remove alumina. The particles are taken out, washed with water, and dried with cold air to obtain a special structure cobalt-based alloy film layer (base material with a composite film layer).

The prepared special structure cobalt-based alloy film layer was placed under a scanning electron microscope to observe its surface morphology. The results are shown in Figure 5. It can be seen from the figure that the surface of the obtained composite film layer is smooth and the special structure is uniform. After testing, the thickness of the obtained special structure cobalt-based alloy film is 12μm, the friction coefficient is 0.78, and when corroded at a current density of 10mA/ ^cm2 , its hydrogen evolution overpotential is 559mV, which is reduced compared with the 572mV of the Co-W coating. 13mV.

Example 6

Preparation method of a special structure cobalt-based alloy film layer:

(1) Preparation of acidic composite plating solution: Add cobalt sulfate, sodium tungstate, complexing agent (diammonium hydrogen citrate), and alumina particles (particle size 5 μm) into the solvent water in sequence, mix, dissolve, and stir evenly to obtain acidic Composite plating solution.

The concentrations of each component are: cobalt sulfate 0.1 mol/L, sodium tungstate 0.1 mol/L, complexing agent (diammonium hydrogen citrate) 0.2 mol/L, and alumina particles 30 g/L. The temperature of the acidic composite plating solution is a constant temperature of 60°C, and the pH value is 5.0.

(2) Immerse the metal base material into the acidic composite plating solution for composite electrodeposition (composite electrodeposition is carried out under air stirring conditions, using a constant current density, the current density is 20mA/cm ² , the electrodeposition time is 60min, and the electrodeposition The temperature is 60℃), after the electrodeposition is completed, take it out, wash with water, and blow dry with cold air; then immerse it in a constant temperature (80℃) reactor containing NaOH solution (concentration: 5mol/L), and corrode for 60 minutes under air stirring to remove alumina. The particles are taken out, washed with water, and dried with cold air to obtain a special structure cobalt-based alloy film layer (base material with a composite film layer).

The surface morphology of the prepared special structure cobalt-based alloy film layer was observed under a scanning electron microscope. The results are shown in Figure 6. It can be seen from the figure that the surface of the obtained composite film layer is smooth and the special structure is uniform. After testing, the thickness of the obtained special structure cobalt-based alloy film is 11μm, the friction coefficient is 0.80, and when corroded at a current density of 10mA/ ^cm2 , its hydrogen evolution overpotential is 562mV, which is reduced compared with the 572mV of the Co-W coating. 10mV.

Comparative example 1

Same as Example 1, except that the composite electrodeposition was not immersed in NaOH solution for corrosion.

The surface morphology of the prepared film was observed under a scanning electron microscope. The results are shown in Figure 7. It can be seen from the figure that the surface of the film is smooth and composite alumina particles can be seen. After testing, the thickness of the obtained film layer was 13 μm, the friction coefficient was 0.58, and its hydrogen evolution overpotential was 568 mV.

Comparative example 2

The same as Example 1, but the difference is that the acidic composite plating solution in step (1) does not contain aluminum oxide particles, and the composite electroplating solution is not immersed in NaOH solution for corrosion after composite electrodeposition.

The surface morphology of the obtained film layer (Co-W coating) was observed under a scanning electron microscope. The results are shown in Figure 8. It can be seen from the figure that the surface of the obtained film layer is smooth, continuous and dense, and has no whisker morphology. After testing, the thickness of the obtained film layer was 8 μm, the friction coefficient was 0.63, and its hydrogen evolution overpotential was 572 mV.

Comparative example 3

Same as Example 1, except that the particle size of the alumina particles is 30 nm.

The surface morphology of the obtained film layer was observed under a scanning electron microscope. The results are shown in Figure 9. It can be seen from the figure that the surface of the obtained film layer is smooth, continuous and uniform, and the special structure is not obvious. After testing, the thickness of the obtained film layer is 11 μm, the friction coefficient is 0.71, and the hydrogen evolution overpotential is 560 mV when corroded at a current density of 10 mA/ ^cm2 , which is 12 mV lower than the 572 mV of the Co-W coating.

Comparative example 4

The same as Example 1, except that the current density of composite electrodeposition is 100 mA/cm ² .

The surface morphology of the obtained composite film layer was observed under a scanning electron microscope. The results are shown in Figure 10. It can be seen from the figure that the surface of the obtained composite film layer is smooth and the special structure is uniform. After testing, the thickness of the obtained composite film layer is 10 μm, the friction coefficient is 0.59, and the hydrogen evolution overpotential is 550 mV when corroded at a current density of 100 mA/ ^cm2 , which is 22 mV lower than the 572 mV of the Co-W coating.

Comparative example 5

Same as Example 1, except that the concentration of cobalt sulfate is 0.15 mol/L.

The surface morphology of the obtained film layer was observed under a scanning electron microscope. The results are shown in Figure 11. It can be seen from the figure that the surface of the obtained film layer is smooth, continuous and uniform, and the special structure is not obvious. After testing, the thickness of the obtained film layer is 5 μm, the friction coefficient is 0.78, and the hydrogen evolution overpotential is 575 mV when corroded at a current density of 10 mA/ ^cm2 , which is an increase of 3 mV compared with the 572 mV of the Co-W coating.

The above-described embodiments only describe the preferred modes of the present invention and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, those of ordinary skill in the art can make various modifications to the technical solutions of the present invention. All deformations and improvements shall fall within the protection scope determined by the claims of the present invention.

Claims (9)

1. A method for preparing a cobalt-based alloy film layer, which is characterized by comprising the following steps: immersing the metal base material in an acidic composite plating solution for composite electrodeposition, and then immersing it in an alkaline solution for immersion corrosion to obtain the cobalt Base alloy film layer; The preparation of the acidic composite plating solution includes: adding cobalt salt, tungsten salt and Al ₂ O ₃ particles into a solvent, mixing, and then adjusting the pH value to acidic to obtain the acidic composite plating solution; The concentration of cobalt salt in the acidic composite plating solution is 0.1mol/L, the concentration of tungsten salt is 0.1mol/L, and the concentration of Al ₂ O ₃ particles is 10 to 30g/L; the pH value of the acidic composite plating solution It is 4.5~6.0. 2. The method for preparing a cobalt-based alloy film according to claim 1, wherein the cobalt salt is cobalt sulfate; and the tungsten salt is sodium tungstate. 3. The method for preparing a cobalt-based alloy film layer according to claim 1, wherein the acidic composite plating solution further contains a complexing agent. 4. The preparation method of cobalt-based alloy film layer according to claim 3, characterized in that the concentration of the complexing agent in the acidic composite plating solution is 0.2~0.4mol/L; the complexing agent is lemon Diammonium hydrogen acid. 5. The preparation method of cobalt-based alloy film layer according to claim 1, characterized in that the conditions of the composite electrodeposition are: constant current density, current density is 10-50mA/cm ² , and electrodeposition time is 30 ~60min, the electrodeposition temperature is 40~70℃. 6. The method for preparing a cobalt-based alloy film according to claim 1, wherein the alkaline solution includes a NaOH solution; the concentration of the NaOH solution is 5 to 7 mol/L. 7. The method for preparing a cobalt-based alloy film layer according to claim 1, wherein the temperature of the immersion corrosion is 60-80°C. 8. A cobalt-based alloy film layer prepared by the preparation method according to any one of claims 1 to 7. 9. Application of the cobalt-based alloy film layer according to claim 8 in the preparation of electrode materials.