Composite alloy films and their preparation methods, battery cathode materials

Abstract

This invention provides a composite alloy film, its preparation method, and a battery cathode material. The preparation method includes: maintaining a vacuum state, activating a substrate, then growing an alloy catalytic film on the substrate surface by ion sputtering a metal target, and then performing surface modification treatment on the alloy catalytic film to obtain the composite alloy film; wherein the elements in the alloy catalytic film include platinum, silver, and fourth-period transition metals, and the fourth-period transition metals include one or more combinations of iron, cobalt, nickel, and chromium. This invention also provides the composite alloy film obtained by the above preparation method and a battery electrode including the composite alloy film. The composite alloy film provided by this invention has the characteristics of corrosion resistance, good catalytic effect, and high cost-effectiveness.

Description

Technical Field

[0001] This invention relates to the field of biomimetic new energy technology, and in particular to a composite alloy film and its preparation method, and a battery cathode material. Background Technology

[0002] Carbon-based materials are commonly used in chemical battery electrodes. These electrodes typically consist of physical layers such as a catalyst layer and a current collector layer bonded together. The catalyst layer is usually composed of an activated carbon support, catalytic material, and binder. While this structure provides a high density of active sites for chemical reactions and electron transfer, the use of organic binders and mechanical pressing processes results in high electrode resistance, and the performance of carbon-based materials like activated carbon is prone to degradation, with a sharp decline in performance after a period of discharge. Platinum and silver are also commonly used materials in chemical battery electrodes; however, large-scale use of metals like platinum and silver to fabricate battery cathodes is costly and limits their catalytic effect. Summary of the Invention

[0003] To address the aforementioned problems, the present invention aims to provide a composite alloy film, its preparation method, and a battery cathode material. The composite alloy film exhibits strong bonding between the catalytic film and the substrate, is not easily detached, and possesses characteristics such as corrosion resistance, good catalytic effect, and high cost-effectiveness.

[0004] To achieve the above objectives, the present invention provides a method for preparing a composite alloy film. The method includes: maintaining a vacuum state, activating a substrate, growing an alloy catalytic film on the substrate surface by ion sputtering, and then modifying the surface of the alloy catalytic film to obtain the composite alloy film. The alloy catalytic film comprises platinum, silver, and a fourth-period transition metal (i.e., the metal target used in the ion sputtering process includes a platinum target, a silver target, and a fourth-period transition metal target), wherein the fourth-period transition metal comprises one or more combinations of iron, cobalt, nickel, and chromium.

[0005] In the above preparation method, compared with pure platinum film, the composite alloy film with the addition of platinum and silver is less expensive, and the atomic structure arrangement of the alloy film is more complex than that of pure platinum film.

[0006] In the above preparation method, doping fourth-period transition metals with heavy metals such as platinum and silver not only reduces the manufacturing cost of the alloy and improves the adhesion between the alloy catalytic film and the substrate, but also results in a composite alloy film that is less prone to peeling and has a longer service life. Furthermore, the addition of elements such as silver, platinum, nickel, and chromium can also improve the corrosion resistance of the composite alloy film.

[0007] In a specific embodiment of the present invention, with the atomic number of all elements in the alloy catalytic film being 100%, the atomic percentage of platinum in the alloy catalytic film is 5-30 at.%, for example 20-30 at.%, and the atomic percentage of silver in the alloy catalytic film is 30-60 at.%. There are no special limitations on the atomic content of other elements (e.g., iron, cobalt, nickel, chromium, etc.) in the alloy catalytic film.

[0008] In a specific embodiment of the present invention, the thickness of the alloy catalytic film after surface modification is generally controlled to be 1μm-10μm.

[0009] In specific embodiments of the present invention, the substrate is generally selected from foamed metal mesh, such as foamed nickel, foamed copper, foamed stainless steel, etc. Foamed stainless steel substrate is preferred.

[0010] In a specific embodiment of the present invention, the activation treatment can remove the oxide layer on the substrate surface, thereby improving the adhesion between the subsequently grown thin film and the substrate. In a specific embodiment, activation treatment is generally performed by ion bombardment, with the vacuum level during ion bombardment typically controlled at 1×10⁻⁶. -2 Pa to 1×10 -3 The bombardment ion energy is 800eV-1000eV, the temperature is 200℃-400℃, and the treatment time is generally controlled at 6-10 minutes. The bombardment ions used in the activation treatment can be Ar ions, etc.

[0011] In a specific embodiment of the present invention, after the substrate is activated, the metal target can be directly sputtered under vacuum conditions to grow an alloy film on the substrate surface. Continuing the activation process with ion sputtering maintains the activated state of the substrate surface, preventing the metal framework (i.e., the metal substrate) from contacting air, keeping the surface clean, saving processing time, and simplifying the process.

[0012] In a specific embodiment of the present invention, the vacuum degree is generally controlled at 6 × 10⁻⁶ during the ion sputtering process. -2 Pa to 5×10 -3 The bombardment ion energy is typically controlled at 600 eV-1000 eV, for example, 800 eV-1000 eV, and the temperature is typically controlled at 200℃-400℃. The bombardment ions used in ion sputtering can be Ar ions, etc.

[0013] In a specific embodiment of the present invention, the thickness of the grown alloy film can be controlled by controlling the deposition time (30min-6h) and sputtering current value (10mA-150mA) during the ion sputtering process; the atomic content of each metal element in the alloy film can be adjusted by controlling the sputtering current value of different target materials.

[0014] In a specific embodiment of the present invention, the surface modification treatment can adjust the micro-nano structure of the alloy catalytic film surface, thereby forming a biomimetic surface. This biomimetic surface can increase the actual surface area of ​​the composite alloy film and increase the number of active sites for oxygen catalytic reduction reaction in the film layer.

[0015] In specific embodiments of the present invention, the surface modification treatment is generally achieved by ion bombardment. In some specific embodiments, the vacuum degree is 2 × 10⁻⁶. -2 Pa to 1×10 -3 Pa, for example 1×10 -2 Pa to 1×10 -3 Pa, bombardment ion energy of 300eV-500eV, temperature of 200℃-400℃, and processing time is generally controlled to be 3min-10min.

[0016] In a specific embodiment of the present invention, the bombardment ions used in the surface modification treatment may be Ar ions or the like.

[0017] This invention provides a composite alloy film obtained by the above-described preparation method. The surface of the composite alloy film generally has a micro / nano structure, and the surface height difference of this structure is generally 10 nm-300 nm (e.g., ...). Figure 1 The height difference between the highest and lowest points of the mid-surface micro / nanostructure is 10 nm to 300 nm.

[0018] This invention further provides a battery cathode material, comprising the aforementioned composite alloy film, wherein the battery includes one of a magnesium fuel cell, an aluminum fuel cell, or a zinc fuel cell. The composite alloy film exhibits good conductivity, corrosion resistance, and a micro / nano structure on its surface. When used as a battery electrode, it demonstrates high catalytic performance and a current density reaching 25 mA / cm². 2 It can maintain stable discharge performance within 300 hours.

[0019] The beneficial effects of this invention are as follows:

[0020] The preparation method provided by this invention does not require carbon-based materials and binders; it only requires the deposition of silver, platinum, and doped metal elements on a substrate surface to obtain a composite alloy film for fabricating thin-film electrodes. This composite alloy film has low fabrication cost, low electrode resistance, large actual surface area, numerous active reaction sites, and high catalytic activity. Attached Figure Description

[0021] Figure 1 The diagram shows the structure of the composite alloy film in Examples 1 to 3.

[0022] Figure 2 This is an atomic force microscope image of the composite alloy film in Example 2. Detailed Implementation

[0023] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0024] Example 1

[0025] This embodiment provides a method for preparing a composite alloy film, including:

[0026] 1. Using nickel foam mesh as a substrate, activation is first performed by argon ion bombardment at a voltage of 800 eV. The ion bombardment conditions are: vacuum degree 1 × 10⁻⁶. -2 Pa, temperature 260℃, time 10min.

[0027] 2. The activated substrate was subjected to ion sputtering, using argon ions to simultaneously sputter platinum, silver, and cobalt targets under the following conditions: argon ion energy of 600 eV and vacuum degree of 6 × 10⁻⁶. -2 At a temperature of 350℃ and sputtering currents of 20mA, 140mA, and 80mA for platinum, silver, and cobalt targets, respectively, a 2μm platinum-silver-cobalt alloy catalytic film was grown on a nickel foam mesh surface after a deposition time of 1 hour. The atomic contents of platinum and silver in the alloy catalytic film were 5 at.%, 60 at.%, and the balance was cobalt.

[0028] 3. Surface modification of the alloy catalytic film was performed by argon ion bombardment of the alloy catalytic film under the following conditions: vacuum degree 1×10⁻⁶. -2 A composite alloy film was obtained by bombarding the film with argon ions at a temperature of 200℃ and a time of 3 min.

[0029] The composite alloy film was immersed in a 0.1 mol / L potassium chloride solution for 30 days and the surface film did not peel off, proving that the composite alloy film prepared in this embodiment has good corrosion resistance.

[0030] Example 2

[0031] This embodiment provides a method for preparing a composite alloy film, including:

[0032] 1. Using nickel foam mesh as a substrate, activation is first performed by argon ion bombardment at a voltage of 900 eV. The ion bombardment conditions are: vacuum degree 1 × 10⁻⁶. -2 Pa, temperature 300℃, time 10min.

[0033] 2. The activated substrate was subjected to ion sputtering, using argon ions to simultaneously sputter platinum, silver, and nickel targets under the following conditions: argon ion energy of 600 eV and vacuum degree of 8 × 10⁻⁶ eV. -2At a temperature of 400℃ and sputtering currents of 25 mA, 130 mA, and 90 mA for platinum, silver, and nickel targets, respectively, an 8 μm platinum-silver-nickel alloy catalytic film was grown on the surface of a nickel foam mesh after a deposition time of 4 h. The atomic contents of platinum and silver in the alloy catalytic film were 8 at.%, 50 at.%, and the balance being nickel.

[0034] 3. Surface modification of the alloy catalytic film was performed by argon ion bombardment of the alloy catalytic film under the following conditions: vacuum degree 2×10⁻⁶. -2 A composite alloy film was obtained by bombarding the film with argon ions at an energy of 400 eV, a temperature of 300 °C, and a time of 5 min.

[0035] The composite alloy film was immersed in a 0.2 mol / L potassium chloride solution for 50 days and the surface film did not peel off, proving that the composite alloy film prepared in this embodiment has good corrosion resistance.

[0036] Example 3

[0037] This embodiment provides a method for preparing a composite alloy film, including:

[0038] 1. Using nickel foam mesh as a substrate, activation is first performed by argon ion bombardment at a voltage of 1000 eV. The ion bombardment conditions are: vacuum degree 1 × 10⁻⁶. -3 Pa, temperature 400℃, time 6min.

[0039] 2. The activated substrate is subjected to ion sputtering, using argon ions to simultaneously sputter platinum, silver, and iron targets under the following conditions: argon ion energy of 800 eV and vacuum degree of 5 × 10⁻⁶. -3 At a temperature of 350℃ and sputtering currents of 70mA, 110mA, and 100mA for platinum, silver, and iron targets, respectively, a 10μm platinum-silver-iron alloy catalytic film was grown on a nickel foam mesh surface after a deposition time of 5 hours. The atomic contents of platinum and silver in the alloy catalytic film were 20 at.%, 40 at.%, and the balance was iron.

[0040] 3. Surface modification of the alloy catalytic film was performed by argon ion bombardment of the alloy catalytic film under the following conditions: vacuum degree 1×10⁻⁶. -3 A composite alloy film was obtained by bombarding with argon ions at an energy of 300 eV, a temperature of 300 °C, and a time of 10 min.

[0041] The composite alloy film was immersed in a 0.3 mol / L potassium chloride solution for 40 days. The surface film did not peel off, which proves that the composite alloy film prepared in this embodiment has good corrosion resistance.

[0042] Figure 1 This is a schematic diagram of the structure of the composite alloy catalytic films prepared in Examples 1 to 3. Figure 1As can be seen, the composite alloy film uses a foam nickel mesh with a porous nickel skeleton as a substrate, on which an alloy catalytic film is deposited. The surface of the alloy catalytic film has a surface micro-nano structure, which can improve the specific surface area of ​​the alloy catalytic film.

[0043] Figure 2 This is an atomic force microscope (AFM) image of the alloy film from Example 2. Figure 2 As can be seen, the surface of the alloy film has obvious micro-nano structures.

[0044] Test Example 1

[0045] The conductivity of the composite alloy films prepared in Examples 1-3 was tested using the double bridge method. The test results are summarized in Table 1. As can be seen from Table 1, the resistivity of the coated nickel foam is not significantly different from that of the uncoated nickel foam, indicating good conductivity. These results demonstrate that the composite alloy films prepared by the method provided in this invention possess good conductivity.

[0046] Table 1

[0047] sample Resistivity (nΩ·m) Example 1 1768.9 Example 2 1765.4 Example 3 1743.5 Uncoated foam nickel 1733.2

[0048] Test Example 2

[0049] In this test example, the composite alloy film from Example 3 was prepared as an electrode, and the performance of the electrode was tested.

[0050] The testing method was as follows: the composite alloy membrane from Example 3 was used as an electrode, serving as the cathode of the testing system. A magnesium alloy plate was selected as the anode, and sodium chloride brine was used as the electrolyte to form a magnesium fuel cell system for testing. The tested current density reached 25 mA / cm². 2 After 300 hours of testing, the current density showed no significant decrease, and the discharge performance remained stable. The test results indicate that the electrode possesses excellent electrochemical reaction kinetics and reaction stability. These results demonstrate that the composite alloy film electrode prepared by the method provided in this invention exhibits superior electrode characteristics.

Claims

1. A method for preparing a composite alloy film, comprising: The substrate is activated under vacuum, and then an alloy catalytic film is grown on the substrate surface by ion sputtering a metal target. The alloy catalytic film is then surface modified to obtain the composite alloy film. The surface of the composite alloy film has a micro-nano structure with a height difference of 10nm-300nm. The surface modification treatment is achieved by ion bombardment, and the vacuum degree during the surface modification treatment is 2×10⁻⁶. -2 Pa to 1×10 -3 Pa, bombardment ion energy of 300eV-500eV, temperature of 200℃-400℃, and treatment time of 3min-10min; The alloy catalytic film contains elements including platinum, silver, and fourth-period transition metals, wherein the fourth-period transition metals include one or more combinations of iron, cobalt, nickel, and chromium. Based on the atomic percentage of all elements in the alloy catalytic film being 100%, the atomic percentage of platinum in the alloy catalytic film is 5-30 at.%, and the atomic percentage of silver is 30-60 at.%.

2. The preparation method according to claim 1, wherein, Platinum has an atomic percentage of 20-30 at.%.

3. The preparation method according to claim 1, wherein, The activation process is performed by ion bombardment.

4. The preparation method according to claim 1, wherein, During the activation process using ion bombardment, the vacuum level is 1×10⁻⁶. -2 Pa to 1×10 -3 Pa, bombardment ion energy of 800eV-1000eV, temperature of 200℃-400℃, and treatment time of 6min-10min.

5. The preparation method according to claim 3 or 4, wherein, The activation treatment uses Ar ions as bombardment ions.

6. The preparation method according to claim 1, wherein, During ion sputtering, the vacuum level is 6 × 10⁻⁶. -2 Pa to 5×10 -3 Pa, bombardment ion energy of 600eV-1000eV, temperature of 200℃-400℃, deposition time of 30min-6h during ion sputtering, and ion sputtering current of 10mA-150mA.

7. The preparation method according to claim 1 or 6, wherein, The bombardment ions used in the ion sputtering include Ar ions.

8. The preparation method according to claim 1, wherein, During the surface modification process, the vacuum degree is 1×10⁻⁶. -2 Pa to 1×10 -3 Pa.

9. The preparation method according to claim 1 or 8, wherein, The surface modification treatment uses bombardment ions including Ar ions.

10. A composite alloy film obtained by the preparation method according to any one of claims 1-9.

11. A battery cathode material comprising the composite alloy membrane of claim 10, wherein the battery comprises one of a magnesium fuel cell, an aluminum fuel cell, and a zinc fuel cell.

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