Anode material, preparation method, electrolysis device and application thereof

Abstract

The invention relates to the technical field of electrolytic hydrogen production, and particularly discloses an anode material, a preparation method of the anode material and application of the anode material in a proton exchange membrane electrolytic cell. The anode material comprises a titanium or titanium alloy substrate and a surface composite coating, and the total thickness of the coating is 0.7-1.5 microns. Along the direction far away from the substrate, the composite material sequentially comprises a first layer (containing oxides of at least two kinds of titanium, and the total oxygen content is gradually decreased in a gradient manner), a transition layer (containing titanium oxides and titanium nitride, the oxygen content is gradually decreased, and the nitrogen content is gradually increased), a second layer (containing titanium nitride) and a third layer (containing noble metal catalytic materials such as Pt / Ir, and the porosity is 25-50%). The anode material is prepared through magnetron sputtering, component gradient control is achieved by dynamically adjusting the argon / oxygen / nitrogen proportion, and argon atmosphere annealing treatment is conducted after deposition. According to the structure, through collaborative optimization of interlayer components and gradients, the corrosion resistance, the conductivity and the service life of the anode material are remarkably improved, and the problems that a traditional anode is prone to passivation and short in service life are solved.

Description

Technical Field

[0001] The present application belongs to the technical field of hydrogen production by electrolysis of water, and specifically relates to anode materials, preparation methods, electrolysis devices and applications. Background Art

[0002] Proton exchange membrane water electrolysis (PEMWE) is a water electrolysis hydrogen production technology based on a proton exchange membrane (PEM) as an electrolyte. Its principle is to separate the anode and cathode via a proton exchange membrane. Water molecules decompose at the anode into hydrogen ions, electrons, and oxygen. The hydrogen ions migrate through the membrane to the cathode, where they combine with electrons to generate hydrogen. Anode materials, including the anode electrode, gas diffusion layer, and bipolar plate, are key components of PEMWE. Metal anode materials are widely used in PEMWE due to their mature processing technology, excellent mechanical properties, electrical and thermal conductivity, and high porosity. However, bare metal anode materials are susceptible to corrosion in the acidic environment of PEMWE. The corrosive ions released during corrosion are toxic to the catalyst. Furthermore, the oxide film formed on the surface increases the interfacial contact resistance, reducing the output power of the PEMWE. Preparing a coating on the surface of a metal anode has become a mainstream method for solving the corrosion problem. In the existing technology, patent CN117364121A discloses a method of providing a multi-layer coating (from an oxide layer to a nitride layer to a precious metal layer) on a metal substrate. This method can improve the corrosion resistance of the anode material. However, it still has problems such as poor conductivity of the oxide layer and insufficient interlayer bonding strength. Summary of the Invention

[0003] In view of the problems existing in the prior art, the purpose of the present invention is to improve the corrosion resistance, electrical conductivity and composite coating interface bonding strength of the metal anode for PEMWE.

[0004] In order to achieve the above-mentioned objectives, the present invention provides an anode material, comprising a substrate and a composite coating arranged on the surface of the substrate, wherein the substrate comprises titanium or a titanium alloy; the composite coating comprises, in sequence from the side close to the substrate to the side away from the substrate, a first layer, a transition layer, a second layer and a third layer, wherein the first layer comprises at least two titanium oxides, and the first layer has an oxygen content gradient that decreases in the direction away from the substrate; the transition layer comprises titanium nitride and titanium oxide, and the transition layer has a nitrogen content gradient that increases and an oxygen content gradient that decreases in the direction away from the substrate; the second layer comprises titanium nitride; the third layer comprises a catalytic material; and the total thickness of the composite coating is 0.7 μm to 1.5 μm.

[0005] Optionally, the thickness ratio of the first layer, transition layer, second layer and third layer of the anode material is (1~2):(1~1.5):(8~15):(0.5~1).

[0006] Optionally, the thickness of the first layer is 80 nm to 200 nm, and the titanium oxide in the first layer includes TiO 2 and Ti 4 O 7 .

[0007] Optionally, the total oxygen content of the first layer is 65.0 at % to 66.0 at %.

[0008] Optionally, the oxygen content of the first layer close to the substrate side is 66.5 at % to 67.0 at %, and the oxygen content of the first layer close to the transition layer side is 63.6 at % to 65.0 at %.

[0009] Optionally, the thickness of the transition layer is 80 nm to 150 nm, and the titanium oxide in the transition layer includes one or both of TiO2 and Ti4O7.

[0010] Optionally, the total oxygen content of the transition layer is 30 at % to 45 at %.

[0011] Optionally, the thickness of the second layer is 500 nm to 1000 nm.

[0012] Optionally, the thickness of the third layer is 50 nm to 100 nm.

[0013] Optionally, the catalytic material in the third layer includes a noble metal or a noble metal alloy, and the noble metal is selected from one or more of Pt, Ir, Au, and Ru.

[0014] Optionally, the porosity of the third layer is 25% to 50%.

[0015] The present invention provides a method for preparing the above-mentioned anode material, comprising: Step 1: pre-treating the substrate surface; Step 2: In an atmosphere of a mixed gas of argon and oxygen at a pressure of 0.5 to 1.5 Pa, a first layer is prepared on the surface of the substrate by magnetron sputtering, and the proportion of oxygen in the mixed gas is gradually reduced during the magnetron sputtering process; Step 3: In an atmosphere of a mixed gas of argon, oxygen, and nitrogen at a pressure of 0.5 to 1.5 Pa, magnetron sputtering is performed on the surface of the first layer to prepare a transition layer, and during the magnetron sputtering process, the proportion of oxygen in the mixed gas is gradually reduced and the proportion of nitrogen is gradually increased; Step 4: In an atmosphere of a mixed gas of argon and nitrogen at a pressure of 0.5-1.0 Pa, a second layer is prepared on the surface of the transition layer by magnetron sputtering; Step 5: In an argon atmosphere with a pressure of 0.6-1.0 Pa, prepare a third layer on the surface of the second layer by magnetron sputtering.

[0016] Optionally, the surface roughness of the substrate after pretreatment is 0.5 μm to 2.0 μm.

[0017] Optionally, during the preparation of the first layer, the substrate temperature is 200~300℃, the power is 100~200W, the deposition rate is 0.2~0.35nm / , the oxygen flow rate in the initial stage is 15~20sccm, and the argon flow rate is 20~30sccm; the oxygen flow rate in the ending stage is 7~15sccm, and the argon flow rate is 30~40sccm.

[0018] Optionally, during the preparation of the transition layer, the substrate temperature is 250~350°C, the power is 200~300W, the deposition rate is 0.25~0.45nm / s, the oxygen flow rate in the initial stage is 15~25sccm, the nitrogen flow rate is 5~10sccm, and the argon flow rate is 30~40sccm; and the oxygen flow rate in the ending stage is 2~5sccm, the nitrogen flow rate is 20~30sccm, and the argon flow rate is 30~40sccm.

[0019] Optionally, during the preparation of the second layer, the substrate temperature is 300~400°C, the power is 300~400W, the deposition rate is 0.3~0.55nm / s; the flow ratio of nitrogen and argon is 1:(2~5), and the total pressure is 0.5~1.0Pa.

[0020] Optionally, during the preparation of the third layer, the substrate temperature is room temperature, the power is 100-150 W, the deposition rate is 0.2-0.3 nm / s, and the argon flow rate is 20-40 sccm.

[0021] Optionally, after completing the preparation of any one of the first layer, transition layer or second layer, turn off the oxygen and / or nitrogen gas source, adjust the argon flow rate to 20~40sccm, turn on the plasma and maintain the power at 200~300W for 2~6 minutes, and then prepare the next layer.

[0022] Optionally, after the third layer is prepared, the method further includes annealing the anode material in an argon atmosphere, wherein the annealing temperature is 300-450° C. and the holding time is 1-3 hours.

[0023] The present invention provides a proton exchange membrane electrolyzer comprising the anode material of the above technical solution.

[0024] The present invention provides a method for producing hydrogen by electrolyzing water using a proton exchange membrane, using the anode material of the above technical solution as the anode.

[0025] The present invention provides a method for producing hydrogen by electrolyzing water using a proton exchange membrane, using the proton exchange membrane electrolyzer of the above technical solution.

[0026] The anode material provided by the present invention has the following beneficial effects: the first layer comprises at least two titanium oxides, with the oxygen content decreasing away from the substrate, which can improve the corrosion resistance of the substrate and balance the conductivity of the first layer; a transition layer is provided between the first and second nitride layers to improve the bonding between the first and second layers; the second layer provides a low-resistance electron transport path, reducing the overall coating resistance; and the third layer provides active sites for the oxygen evolution reaction. As a result, the present invention can improve the corrosion resistance, conductivity, interlayer bonding, and service life of the anode material.

[0027] The preparation method provided by the present invention realizes the integrated construction of the composite coating from "composition gradient to interface compatibility to functional synergy" through precise control of the gas ratio and coordinated design of the preparation process of each layer, thereby ensuring the systematic optimization of the anode material in corrosion resistance, conductivity, bonding strength and catalytic activity from the preparation end. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a cross-sectional SEM image of the anode material composite coating of Example 2 of the present invention. DETAILED DESCRIPTION

[0029] The present invention will be described in detail below with reference to specific embodiments. The embodiments shown below do not limit the invention as described in the claims. In addition, the entire contents of the structures shown in the following embodiments are not limited to those necessary for the solution of the invention as described in the claims.

[0030] As used herein, the term "comprise" should be interpreted as inclusive and open-ended, rather than exclusive. Specifically, when used in the specification and claims, the term "comprises" and its variations mean including the specified features, steps, or components. These terms should not be interpreted as excluding the presence of other features, steps, or components.

[0031] In this document, the terms "first," "second," "third," etc. are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first," "second," or "third" may explicitly or implicitly include at least one of such features.

[0032] Whenever a range of values is given herein, that range includes its endpoints, and all individual integers and fractions within that range, and also includes each narrower range formed from all possible combinations of those endpoints and internal integers and fractions therein to form subgroups of the larger group of values within that range to the same extent as if each of those narrower ranges were expressly set forth.

[0033] The first aspect of the present application provides an anode material, comprising a substrate and a composite coating disposed on the surface of the substrate, wherein the substrate comprises titanium material or titanium alloy material such as titanium felt, titanium sheet, titanium mesh, or titanium plate; the composite coating comprises at least a first layer, a transition layer, a second layer, and a third layer in sequence in a direction away from the substrate, wherein the first layer comprises at least two titanium oxides, and the oxygen content in the first layer decreases in a direction away from the substrate; the transition layer comprises titanium nitride and titanium oxide, and the nitrogen content in the transition layer increases and the oxygen content decreases in a direction away from the substrate; the second layer comprises titanium nitride; and the third layer comprises a catalyst. The anode material of the present application breaks through the inherent contradictions of corrosion resistance, conductivity, and bonding strength of traditional anode materials through the multi-dimensional design of the composite coating from "composition gradient to interface compatibility to functional synergy", thereby improving service life and electrochemical performance.

[0034] The first layer of the anode material in this application is a titanium oxide layer, comprising at least two titanium oxides. Compared to low-oxygen titanium oxides (such as Ti4O7), high-oxygen titanium oxides (such as TiO2) have a better match in lattice parameters and thermal expansion coefficient with the titanium or titanium alloy substrate, resulting in a stronger interfacial bond with the substrate. Furthermore, the denser crystal structure of high-oxygen titanium oxides effectively hinders the penetration of corrosive media, significantly improving the corrosion resistance of the substrate. Low-oxygen titanium oxides (such as Ti4O7) exhibit significantly better conductivity than high-oxygen oxides due to the presence of more oxygen vacancies and electron defects, thus optimizing the conductivity of the first layer. Furthermore, the oxygen content in the first layer decreases away from the substrate, creating a gradient distribution. This gradient design allows the thermal expansion coefficient within the coating to gradually transition from the substrate to the surface, avoiding interfacial stress concentration caused by sudden performance changes and further improving the structural stability of the coating.

[0035] As the transition layer moves away from the substrate, the nitrogen content increases and the oxygen content decreases, allowing the oxide and nitride to form an atomic-level mixed transition zone. This eliminates stress concentration caused by hard interface mutations, promotes interlayer atomic diffusion, and improves bonding strength through chemical compatibility and mechanical interlocking. Furthermore, the increase in nitrogen content gradually activates the conductive phase, achieving a low-resistance transition from oxide to nitride.

[0036] The second layer of titanium nitride, as a highly conductive phase, can construct a continuous electron transmission path, and its high conductivity characteristics can reduce the overall resistance of the coating.

[0037] The third catalyst layer can provide active sites for the reaction. At the same time, relying on the rigid support of the lower titanium nitride layer and the stress buffering effect of the gradient structure, it can delay the shedding and dissolution of the catalyst under high potential, thereby achieving synergistic optimization of catalytic activity and structural stability.

[0038] In some embodiments, the thickness ratio of the first layer, the transition layer, the second layer, and the third layer is (1 to 2): (1 to 1.5): (8 to 15): (0.5 to 1). This can further improve the service life and electrochemical performance.

[0039] In some embodiments, the thickness of the first layer is 80 nm to 200 nm. Meeting this thickness range can further form a continuous and dense corrosion-resistant barrier, and can further relieve interfacial stress, thereby further improving corrosion resistance and structural stability.

[0040] In some embodiments, the oxygen content in the first layer gradually decreases away from the substrate. This application further defines a gradual change in the oxygen content of the first layer to further form a continuous lattice parameter transition region, thereby avoiding stress concentration caused by sudden compositional changes and ensuring a smooth electron conduction path from the substrate to the coating, further synergistically optimizing corrosion resistance and electrical conductivity.

[0041] In some embodiments, the titanium oxide in the first layer includes TiO2 and Ti4O7. TiO2 can provide high corrosion resistance, and Ti4O7 can contribute good conductivity. The two synergistically form a "corrosion-resistant and conductive" dual-functional layer, further protecting the substrate while reducing electron transport resistance.

[0042] In some embodiments, the total oxygen content of the first layer is 66.5 to 67.0 at%, which allows the titanium oxide to be within the optimal ratio of TiO2 to Ti4O7, further balancing the density and electronic conductivity of the passivation film, and further improving the matching of corrosion resistance and electrical conductivity. The oxygen content of the first layer near the substrate is 66.5 to 67.0 at%, forming a highly dense oxide layer near the substrate, further effectively inhibiting oxidation and corrosion of the substrate and further improving the bonding strength between the first layer and the substrate.

[0043] In some embodiments, the oxygen content of the first layer near the transition layer is 63.6 at % to 65.0 at %, which can improve interlayer conductivity, smoothly connect the nitride conductive phase of the transition layer, and further reduce interface resistance.

[0044] In some embodiments, the thickness of the transition layer is 80 nm to 150 nm, which can further form an atomic mixing transition zone of sufficient width, further alleviate the stress mutation between oxide and nitride, and provide a continuous percolation path for electron conduction, thereby further enhancing the bonding force and conductivity.

[0045] In some embodiments, the nitrogen content of the transition layer gradually increases and the oxygen content gradually decreases as it moves away from the substrate. This application further stipulates that the transition layer meets the above conditions to further smooth the transition of interlayer chemical bond types (from Ti to O to Ti to N), further eliminating interfacial charge accumulation, thereby further reducing contact resistance and improving structural stability.

[0046] In some embodiments, the titanium oxide in the transition layer includes one or both of TiO2 and Ti4O7. The present application further stipulates that the transition layer satisfies the above conditions and can further form functional synergy with the first layer and the second layer to further optimize the overall performance of the entire coating.

[0047] In some embodiments, the total oxygen content in the transition layer is 30 at % to 45 at %. The present application further stipulates that the transition layer meets the above conditions, which can further improve the conductivity while maintaining structural integrity.

[0048] In some embodiments, the thickness of the second layer is 500 nm to 1000 nm. The present application further stipulates that the second layer meets the above conditions, which can further promote the formation of a continuous three-dimensional conductive network of titanium nitride, further reduce the overall resistance of the coating, and further provide sufficient mechanical support for the upper catalyst layer, thereby further suppressing structural deformation during service.

[0049] In some embodiments, the thickness of the third layer is 50 nm to 100 nm. This application further stipulates that the third layer meets the above conditions, which can further provide sufficient catalytic active sites for the reaction and further avoid internal stress cracking of the catalyst layer due to excessive thickness through the stress buffering effect of the gradient structure, thereby further extending the service life of the catalyst.

[0050] In some embodiments, the catalyst includes a noble metal, thereby further improving the performance of the anode material.

[0051] In some embodiments, the noble metal includes one or more of Pt, Ir, Au, and Ru. This can further improve the performance of the anode material.

[0052] In some embodiments, the porosity of the third layer is 25% to 50%, which can further enable the multi-level pore structure formed by the third layer to take into account both the transport of reactants and the exposure of active sites, while further suppressing the penetration of electrolyte through the capillary force of the pore wall, thereby further extending the service life of the catalyst layer.

[0053] It should be noted that the shapes of the anode and substrate of the present application can be various, such as flat, rod-shaped or any other required shape, and the present application does not impose too many restrictions here; the composite coating can cover the entire outer surface of the substrate, or it can cover part of the outer surface, and the specific shape can be adjusted according to actual needs, and the present application does not impose too many restrictions here.

[0054] This application provides some methods for measuring the thickness and composition of anode material coatings, which are for reference only and do not constitute a limitation of this application. Specifically, they include: Cutting: Before testing the composite coating, the finished anode material can be cut to expose the longitudinal cross-section of the composite coating. The cutting method can be selected based on actual conditions, such as mechanical cutting plus ion beam polishing, FIB cutting, neutral ion beam cutting, FIB+STEM to EELS combination, etc. Other methods can also be selected, and this application does not impose any restrictions on this. Layer detection: EDS can be used to scan the cross section of the composite coating. The surface distribution image can intuitively display the spatial distribution of each element in the layer, and the thickness data of each layer can be obtained through measurement. Other methods can also be used, which are not limited in this application. Detection of titanium oxide types: The types of titanium oxides can be analyzed by methods such as XRD and XPS, or other methods can be used, which are not limited in this application.

[0055] The second aspect of the present application provides a method for preparing an anode material, comprising: pre-treating the surface of a substrate; preparing a first layer on the surface of the substrate by magnetron sputtering in a mixed gas atmosphere of argon and oxygen at a pressure of 0.5 to 1.5 Pa, and gradually reducing the proportion of oxygen in the mixed gas during the magnetron sputtering process; preparing a transition layer on the surface of the first layer by magnetron sputtering in a mixed gas atmosphere of argon, oxygen, and nitrogen at a pressure of 0.5 to 1.5 Pa, and gradually reducing the proportion of oxygen and increasing the proportion of nitrogen in the mixed gas during the magnetron sputtering process; preparing a second layer on the surface of the transition layer by magnetron sputtering in a mixed gas atmosphere of argon and nitrogen at a pressure of 0.5 to 1.0 Pa; and preparing a third layer on the surface of the second layer by magnetron sputtering in an argon atmosphere at a pressure of 0.6 to 1.0 Pa.

[0056] The anode material preparation method provided in this application can systematically improve the comprehensive performance of the material through the dynamic regulation of the gas atmosphere in the magnetron sputtering process and the layered preparation strategy. The specific mechanism of action is as follows: (1) First, the substrate surface is pretreated to remove the oxide layer and optimize the surface roughness, providing a highly active adhesion interface for the coating and enhancing the initial bonding ability between the substrate and the coating. When preparing the first layer, the oxygen content is dynamically reduced in the Ar / oxygen mixed gas atmosphere, so that the titanium oxide transitions from a high oxygen content to a low oxygen content gradient. Combined with the temperature / power synergistic effect, at least two titanium oxides are generated in the first layer, forming a functional layer with a gradual matching of lattice parameters and thermal expansion coefficients. The dense oxidation structure in the high oxygen zone can effectively block the penetration of the electrolyte and improve corrosion resistance; the low-valent oxide in the low oxygen zone improves the conductivity within the layer, achieving a functional balance from "corrosion resistance to conductivity" and at the same time alleviating the stress concentration between the substrate and the coating; (2) In the preparation of the transition layer, the ratio of oxygen and nitrogen is synchronously adjusted so that the nitrogen content increases and the oxygen content decreases, thereby constructing a titanium oxide-nitrogen solid solution transition zone with a nitrogen-oxygen element gradient. This gradient structure eliminates the "hard interface" mutation between oxides and nitrides, promotes interlayer atomic diffusion and chemical bonding, enhances interfacial compatibility, significantly improves interlayer bonding strength and reduces internal stress; (3) The second layer is titanium nitride deposited in an Ar / nitrogen atmosphere to form a continuous high-conductivity phase, construct a low-resistance electron transmission path, and ensure efficient conduction of electrons from the substrate to the catalyst layer; (4) The third layer is formed in pure argon by controlling the sputtering parameters to form a catalyst layer with appropriate thickness and pore structure, which not only increases the exposed area of active sites to improve the catalytic reaction efficiency, but also relies on the rigid support of the lower layer and the stress buffering effect of the gradient structure to enhance the stability of the catalyst in a high potential environment.

[0057] In some embodiments, during the preparation of the first layer, the substrate temperature is 200°C to 300°C, the power is 200W to 300W, and the deposition rate is 0.2nm / s to 0.35nm / s. During the initial stage, the oxygen flow rate is 15sccm to 20sccm, and the argon flow rate is 20sccm to 30sccm; during the final stage, the oxygen flow rate is 7sccm to 15sccm, and the argon flow rate is 30sccm to 40sccm. Through dynamic oxygen flow control and coordinated temperature / power optimization, the coexistence of TiO2 and Ti4O7 in the first layer is guaranteed from both thermodynamic and kinetic perspectives, thereby further improving the performance of the anode material.

[0058] In some embodiments, during the preparation of the transition layer, the substrate temperature is 250°C to 350°C, the power is 200W to 300W, and the deposition rate is 0.25nm / s to 0.45nm / s. In the initial stage, the oxygen flow rate is 15sccm to 25sccm, the nitrogen flow rate is 5sccm to 10sccm, and the argon flow rate is 30sccm to 40sccm. In the final stage, the oxygen flow rate is 2sccm to 5sccm, the nitrogen flow rate is 20sccm to 30sccm, and the argon flow rate is 30sccm to 40sccm. This can further improve the performance of the anode material.

[0059] In some embodiments, during the preparation of the second layer, the substrate temperature is 300° C. to 400° C., the power is 300 W to 400 W, the deposition rate is 0.3 nm / s to 0.55 nm / s, the nitrogen to argon flow ratio is 1:(2-5), and the total pressure is 0.5 Pa to 1.0 Pa. This can further improve the performance of the anode material.

[0060] In some embodiments, during the preparation of the third layer, the substrate temperature is between 150°C and 250°C, the power is between 100W and 150W, the deposition rate is between 0.2nm / s and 0.3nm / s, and the argon flow rate is between 20sccm and 40sccm. This can further improve the performance of the anode material.

[0061] In some embodiments, after the first layer, transition layer, or second layer is formed, the oxygen and / or nitrogen gas sources are turned off, the argon flow rate is adjusted to 20 sccm to 40 sccm, and the plasma is initiated and maintained at a power of 200 W to 300 W for 2 to 6 minutes before the next layer is formed. High-energy argon plasma bombardment effectively removes adsorbed impurities, loose layers, and residual reactive gases from the surface of the layer, improving surface roughness and activating surface atomic activity, thereby enhancing mechanical interlocking and chemical bonding at the interface and improving interlayer bonding strength.

[0062] In some embodiments, the method further comprises annealing the anode material after the third layer is prepared in an argon atmosphere at an annealing temperature of 300°C to 450°C and a holding time of 1 hour to 3 hours. High-temperature annealing can promote the transformation of the catalyst layer from an amorphous to a crystalline structure, thereby increasing the density of catalytically active sites. It can also promote stress release within the coating, enhance interlayer atomic diffusion, and form a more stable interlayer interface. In addition, the annealing treatment can also optimize the uniformity of the pore structure, improve pore connectivity while maintaining porosity, and further improve the catalytic activity, structural stability, and long-term service life of the anode material.

[0063] Example 1 This embodiment prepares the anode material by the following steps: (1) Substrate pretreatment

[0064] A titanium alloy substrate was selected and its surface was sandblasted to achieve a surface roughness of 1.2 μm.

[0065] (2) Preparation of the first layer by magnetron sputtering

[0066] Using a pure titanium target as the source material, magnetron sputtering was performed in an atmosphere of argon and oxygen at a pressure of 1.0 Pa. The substrate temperature was set at 250°C, the power was 200 W, and the deposition rate was 0.25 nm / s. Initially, the oxygen flow rate was 18 sccm and the argon flow rate was 25 sccm; at the end, the oxygen flow rate was 10 sccm and the argon flow rate was 35 sccm. The first layer was deposited on the substrate surface by magnetron sputtering, with a controlled thickness of 150 nm.

[0067] After testing, it was found that the titanium oxides in the first layer were TiO2 and Ti4O7. The oxygen content near the substrate was about 66.75at%, the oxygen content near the transition layer was about 64.3at%, and the total oxygen content was about 65.5at%. The oxygen content gradually decreased away from the substrate.

[0068] (3) Preparation of transition layer by magnetron sputtering

[0069] After the first layer was prepared, the oxygen source was turned off, the argon flow rate was adjusted to 30 sccm, the plasma was turned on and the power was maintained at 250 W for 4 min.

[0070] A transition layer was then deposited using a pure titanium target as the source material by magnetron sputtering in a mixed atmosphere of argon, oxygen, and nitrogen at a pressure of 1.0 Pa. The substrate temperature was set at 300°C, the power at 250 W, and the deposition rate at 0.35 nm / s. Initially, the oxygen flow rate was 20 sccm, the nitrogen flow rate was 7.5 sccm, and the argon flow rate was 35 sccm. At the end, the oxygen flow rate was 3 sccm, the nitrogen flow rate was 25 sccm, and the argon flow rate was 35 sccm. The transition layer thickness was controlled to 115 nm.

[0071] After testing, it was found that the titanium oxides in the transition layer were TiO2 and Ti4O7. The nitrogen content gradually increased and the oxygen content gradually decreased as it moved away from the substrate. The total oxygen content was about 37.5at%.

[0072] (4) Preparation of the second layer by magnetron sputtering

[0073] After the transition layer was prepared, the oxygen and nitrogen gas sources were turned off, the argon flow rate was adjusted to 30 sccm, the plasma was turned on and the power was maintained at 250 W for 4 min.

[0074] Then, using a pure titanium target as the source material, the second layer was prepared by magnetron sputtering in a mixed gas atmosphere of argon and nitrogen at a pressure of 0.75 Pa, a substrate temperature of 350°C, a power of 350 W, a deposition rate of 0.3 nm / s, and a nitrogen to argon flow ratio of 1:3. The thickness of the layer was controlled to be 750 nm.

[0075] After testing, it was found that the second layer was composed of titanium nitride.

[0076] (5) Preparation of the third layer by magnetron sputtering

[0077] After the second layer was prepared, the nitrogen gas source was turned off, the argon flow rate was adjusted to 30 sccm, the plasma was turned on and the power was maintained at 250 W for 4 min.

[0078] Then, a third layer was prepared by magnetron sputtering using a Pt target as the source material in an argon atmosphere with a pressure of 0.8 Pa, a substrate at room temperature, a power of 70 W, a deposition rate of 0.25 nm / s, an argon flow rate of 55 sccm, and a controlled thickness of 75 nm.

[0079] After testing, the porosity of the third layer is 37.5%.

[0080] (6) Annealing

[0081] The anode material after the third layer preparation is annealed in an argon atmosphere at an annealing temperature of 400° C. and a holding time of 1.5 h.

[0082] Example 2 This embodiment prepares the anode material by the following steps: (1) Substrate pretreatment

[0083] A titanium substrate was selected and its surface was sandblasted to make the surface roughness reach 0.5 μm.

[0084] (2) Preparation of the first layer by magnetron sputtering

[0085] The first layer was deposited by magnetron sputtering using a pure titanium target as the source material in an atmosphere of argon and oxygen at a pressure of 0.5 Pa. The substrate temperature was set at 200°C, the power was 100 W, and the deposition rate was 0.2 nm / s. The initial flow rates were 15 sccm of oxygen and 20 sccm of argon; the final flow rates were 7 sccm of oxygen and 30 sccm of argon. The controlled thickness was 80 nm.

[0086] After testing, the titanium oxides are TiO2 and Ti4O7. The oxygen content near the base side is about 66.5at%, the oxygen content near the transition layer side is about 63.6at%, and the total oxygen content is about 65.0at%. The oxygen content gradually decreases away from the base.

[0087] (3) Preparation of transition layer by magnetron sputtering

[0088] After the first layer was prepared, the oxygen source was turned off, the argon flow rate was adjusted to 20 sccm, the plasma was turned on and the power was maintained at 200 W for 2 min.

[0089] A transition layer was then deposited using a pure titanium target as the source material by magnetron sputtering in a mixed atmosphere of argon, oxygen, and nitrogen at a pressure of 0.5 Pa. The substrate temperature was set at 250°C, the power at 200 W, and the deposition rate at 0.25 nm / s. The initial flow rates were: 15 sccm of oxygen, 5 sccm of nitrogen, and 30 sccm of argon; and 2 sccm of oxygen, 20 sccm of nitrogen, and 30 sccm of argon at the end. The thickness was controlled to be 80 nm.

[0090] According to the test, the titanium oxide in the transition layer is TiO2, the nitrogen content gradually increases and the oxygen content gradually decreases as it moves away from the substrate, and the total oxygen content is about 30at%.

[0091] (4) Preparation of the second layer by magnetron sputtering

[0092] After the transition layer was prepared, the oxygen and nitrogen gas sources were turned off, the argon flow rate was adjusted to 20 sccm, the plasma was turned on and the power was maintained at 200 W for 2 min.

[0093] Then, a pure titanium target was used as the source material, and the second layer was prepared by magnetron sputtering in a mixed gas atmosphere of argon and nitrogen at a pressure of 0.5 Pa. The substrate temperature was 300°C, the power was 300 W, the deposition rate was 0.3 nm / s, the nitrogen and argon flow ratio was 1:2, and the thickness was controlled to be 750 nm.

[0094] After testing, it was found that the second layer was composed of titanium nitride.

[0095] (5) Preparation of the third layer by magnetron sputtering

[0096] After the second layer was prepared, the nitrogen gas source was turned off, the argon flow rate was adjusted to 20 sccm, and the plasma was turned on and the power was maintained at 200 W for 2 min.

[0097] A third layer with a thickness of 50 nm and Ir as the catalyst was deposited by magnetron sputtering using an Ir target as the source material in an argon atmosphere at a pressure of 0.6 Pa, at room temperature, a power of 100 W, a deposition rate of 0.2 nm / s, and an argon flow rate of 20 sccm. Testing showed a porosity of 25% in the third layer.

[0098] (6) Annealing

[0099] The anode material after the third layer is prepared is annealed in an argon atmosphere at an annealing temperature of 300° C. and a holding time of 1 h.

[0100] Example 3 This embodiment prepares the anode material by the following steps: (1) Substrate pretreatment

[0101] A titanium alloy substrate was selected and its surface was sandblasted to make the surface roughness reach 2.0 μm.

[0102] (2) Preparation of the first layer by magnetron sputtering

[0103] The first layer was deposited using a pure titanium target as the source material by magnetron sputtering in an atmosphere of argon and oxygen at a pressure of 1.5 Pa. The substrate temperature was set at 300°C, the power was 200 W, and the deposition rate was 0.35 nm / s. The initial oxygen flow rate was 20 sccm and the argon flow rate was 30 sccm; the final flow rate was 15 sccm and 40 sccm, respectively, to achieve a controlled thickness of 200 nm.

[0104] After testing, the titanium oxides in the first layer are TiO2 and Ti4O7. The oxygen content near the substrate side is about 67.0at%, the oxygen content near the transition layer side is about 65.0at%, and the total oxygen content is about 66.0at%. The oxygen content gradually decreases away from the substrate.

[0105] (3) Preparation of transition layer by magnetron sputtering

[0106] After the first layer was prepared, the oxygen source was turned off, the argon flow rate was adjusted to 40 sccm, and the plasma was turned on and the power was maintained at 300 W for 6 min.

[0107] A pure titanium target was then used as the source material. Magnetron sputtering was used in a mixed atmosphere of argon, oxygen, and nitrogen at a pressure of 1.5 Pa, with a substrate temperature of 350°C, a power of 300 W, and a deposition rate of 0.45 nm / s. Initially, the oxygen flow rate was 25 sccm, the nitrogen flow rate was 10 sccm, and the argon flow rate was 40 sccm. Finally, the oxygen flow rate was 5 sccm, the nitrogen flow rate was 30 sccm, and the argon flow rate was 40 sccm. A transition layer was deposited to a controlled thickness of 150 nm.

[0108] After testing, it was found that the titanium oxide in the transition layer was Ti4O7. The nitrogen content gradually increased and the oxygen content gradually decreased as it moved away from the substrate. The total oxygen content was about 45at%.

[0109] (4) Preparation of the second layer by magnetron sputtering

[0110] After the transition layer was prepared, the oxygen and nitrogen gas sources were turned off, the argon flow rate was adjusted to 40 sccm, the plasma was turned on and the power was maintained at 300 W for 6 min.

[0111] Then, using a pure titanium target as the source material, the second layer was prepared by magnetron sputtering in a mixed gas atmosphere of argon and nitrogen at a pressure of 1.0 Pa. The substrate temperature was 400°C, the power was 400 W, the deposition rate was 0.55 nm / s, the nitrogen and argon flow ratio was 1:5, and the thickness was controlled to be 1000 nm.

[0112] After testing, it was found that the second layer was composed of titanium nitride.

[0113] (5) Preparation of the third layer by magnetron sputtering

[0114] After the second layer was prepared, the nitrogen gas source was turned off, the argon flow rate was adjusted to 40 sccm, and the plasma was turned on and the power was maintained at 300 W for 6 min.

[0115] A third layer with a thickness of 100 nm was then deposited using a Ru target as the source material in an argon atmosphere at a pressure of 1.0 Pa, with the substrate at room temperature, a power of 150 W, a deposition rate of 0.3 nm / s, and an argon flow rate of 40 sccm. Testing showed that the porosity of the third layer was 50%.

[0116] (6) Annealing

[0117] The anode material after the third layer is prepared is annealed in an argon atmosphere at an annealing temperature of 450° C. and a holding time of 3 h.

[0118] Example 4 This embodiment prepares the anode material by the following steps: (1) Substrate pretreatment

[0119] A titanium substrate was selected and its surface was sandblasted to make the surface roughness reach 1.0 μm.

[0120] (2) Preparation of the first layer by magnetron sputtering

[0121] The first layer was deposited using a pure titanium target as the source material by magnetron sputtering in an atmosphere of argon and oxygen at a pressure of 0.8 Pa. The substrate temperature was set at 220°C, the power was 120 W, and the deposition rate was 0.25 nm / s. The initial oxygen flow rate was 16 sccm and the argon flow rate was 22 sccm; the final flow rate was 10 sccm and 32 sccm, respectively, to achieve a controlled thickness of 100 nm.

[0122] After testing, it was found that the titanium oxides in the first layer were TiO2 and Ti4O7. The oxygen content near the substrate was about 66.6at%, the oxygen content near the transition layer was 64.0at%, and the total oxygen content was 65.3at%. The oxygen content gradually decreased away from the substrate.

[0123] (3) Preparation of transition layer by magnetron sputtering

[0124] After the first layer was prepared, the oxygen source was turned off, the argon flow rate was adjusted to 25 sccm, the plasma was turned on and the power was maintained at 220 W for 3 min.

[0125] A transition layer was then deposited using a pure titanium target as the source material by magnetron sputtering in a mixed atmosphere of argon, oxygen, and nitrogen at a pressure of 0.8 Pa. The substrate temperature was 280°C, the power was 230 W, and the deposition rate was 0.30 nm / s. Initially, the oxygen flow rate was 18 sccm, the nitrogen flow rate was 6 sccm, and the argon flow rate was 32 sccm. At the end, the oxygen flow rate was 4 sccm, the nitrogen flow rate was 22 sccm, and the argon flow rate was 32 sccm, achieving a controlled thickness of 120 nm.

[0126] According to detection, the titanium oxide of the transition layer of this embodiment is TiO2, the nitrogen content gradually increases and the oxygen content gradually decreases in the direction away from the substrate, and the total oxygen content is about 35at%.

[0127] (4) Preparation of the second layer by magnetron sputtering

[0128] After the transition layer was prepared, the oxygen and nitrogen gas sources were turned off, the argon flow rate was adjusted to 25 sccm, the plasma was turned on and the power was maintained at 220 W for 3 min.

[0129] Then, using a pure titanium target as the source material, the second layer was prepared by magnetron sputtering in a mixed gas atmosphere of argon and nitrogen at a pressure of 0.6 Pa. The substrate temperature was 320°C, the power was 320 W, the deposition rate was 0.4 nm / s, the nitrogen and argon flow ratio was 1:2.5, and the thickness was controlled to be 650 nm.

[0130] After testing, it was found that the second layer was composed of titanium nitride.

[0131] (5) Preparation of the third layer by magnetron sputtering

[0132] After the second layer was prepared, the nitrogen gas source was turned off, the argon flow rate was adjusted to 25 sccm, the plasma was turned on and the power was maintained at 220 W for 3 min.

[0133] Then, using a Pt target as the source material, the third layer was prepared by magnetron sputtering in an argon atmosphere with a pressure of 0.7 Pa. The substrate temperature was room temperature, the power was 110 W, the deposition rate was 0.22 nm / s, the argon flow rate was 22 sccm, and the thickness was controlled to be 60 nm.

[0134] After testing, the porosity of the third layer is 30%.

[0135] (6) Annealing

[0136] The anode material after the third layer is prepared is annealed in an argon atmosphere at an annealing temperature of 350° C. and a holding time of 1.5 h.

[0137] Example 5 This embodiment prepares the anode material by the following steps: (1) Substrate pretreatment

[0138] A titanium alloy substrate was selected and its surface was sandblasted to achieve a surface roughness of 1.8 μm.

[0139] (2) Preparation of the first layer by magnetron sputtering

[0140] The first layer was deposited using a pure titanium target as the source material by magnetron sputtering in an atmosphere of argon and oxygen at a pressure of 1.2 Pa. The substrate temperature was set at 280°C, the power was 180 W, and the deposition rate was 0.28 nm / s. The initial oxygen flow rate was 16 sccm and the argon flow rate was 28 sccm; the final flow rate was 12 sccm and 38 sccm, achieving a controlled thickness of 180 nm.

[0141] After testing, the oxides of the first layer of titanium are TiO2 and Ti4O7. The oxygen content near the substrate is about 66.8at%, the oxygen content near the transition layer is about 64.5at%, and the total oxygen content is about 65.8at%. The oxygen content gradually decreases away from the substrate.

[0142] (3) Preparation of transition layer by magnetron sputtering

[0143] After the first layer was prepared, the oxygen source was turned off, the argon flow rate was adjusted to 35 sccm, the plasma was turned on and the power was maintained at 280 W for 5 min.

[0144] A transition layer was then deposited using a pure titanium target as the source material by magnetron sputtering in a mixed atmosphere of argon, oxygen, and nitrogen at a pressure of 1.2 Pa. The substrate temperature was 330°C, the power was 280 W, and the deposition rate was 0.4 nm / s. The initial flow rates were 22 sccm of oxygen, 8 sccm of nitrogen, and 38 sccm of argon; at the end, the flow rates were 4.5 sccm of oxygen, 28 sccm of nitrogen, and 38 sccm of argon, achieving a controlled thickness of 140 nm.

[0145] After testing, it was found that the titanium oxide in the transition layer was Ti4O7. The nitrogen content gradually increased and the oxygen content gradually decreased as it moved away from the substrate. The total oxygen content was about 40at%.

[0146] (4) Preparation of the second layer by magnetron sputtering

[0147] After the transition layer was prepared, the oxygen and nitrogen gas sources were turned off, the argon flow rate was adjusted to 35 sccm, the plasma was turned on and the power was maintained at 280 W for 5 min.

[0148] Then, a pure titanium target was used as the source material, and the second layer was prepared by magnetron sputtering in a mixed gas atmosphere of argon and nitrogen at a pressure of 0.9 Pa. The substrate temperature was 380°C, the power was 380 W, the deposition rate was 0.45 nm / s, the nitrogen and argon flow ratio was 1:4.5, and the thickness was controlled to be 800 nm.

[0149] After testing, it was found that the second layer was composed of titanium nitride.

[0150] (5) Preparation of the third layer by magnetron sputtering

[0151] After the second layer was prepared, the nitrogen gas source was turned off, the argon flow rate was adjusted to 35 sccm, the plasma was turned on and the power was maintained at 280 W for 5 min.

[0152] Then, the third layer was prepared by magnetron sputtering using an Au target as the source material in an argon atmosphere with a pressure of 0.9 Pa. The substrate temperature was room temperature, the power was 125 W, the deposition rate was 0.28 nm / s, the argon flow rate was 35 sccm, and the thickness was controlled to be 90 nm.

[0153] After testing, the porosity of the third layer is 45%.

[0154] (6) Annealing

[0155] The anode material after the third layer is prepared is annealed in an argon atmosphere at an annealing temperature of 430° C. and a holding time of 2 h.

[0156] Comparative Example 1 The difference between this comparative example and Example 2 is that the substrate is not pretreated and a coating is not prepared on the substrate.

[0157] Comparative Example 2 The difference between this comparative example and Example 2 is that the oxygen gas is kept constant at 30 ccm when preparing the first layer, and other conditions are the same.

[0158] Comparative Example 3 The difference between this comparative example and Example 2 is that no transition layer is prepared between the first layer and the second layer, and other conditions are the same.

[0159] Comparative Example 4 The difference between this comparative example and Example 2 is that the first layer is not prepared, and other conditions are the same.

[0160] The anode materials of Examples 1 to 5 and Comparative Examples 1 to 3 were subjected to potentiostatic electrochemical polarization curves using a three-electrode system in a 0.5 mol / L H₂SO₄ + 5 ppm HF solution at 80°C in a water bath. Contact resistance was measured using a contact resistance tester. Adhesion was tested using a BGD500 digital tensile tester in accordance with GB / T 5210-2006. Coating hardness was measured using a DuPont hardness tester. Test data for adhesion, hardness, corrosion current density, corrosion current density after 100 hours of constant potential operation, contact resistance, and contact resistance after 100 hours of constant potential operation are shown in Table 1.

[0161]

[0162] As can be seen from Table 1, the comprehensive performance of the composite coatings of the anode materials prepared in Examples 1 to 5 of the present application is significantly better than that of Comparative Examples 1 to 4. According to the test results in Table 1, the adhesion between the anode materials of the present application and the substrate is above 11 MPa, the coating hardness is not less than 21 GPa, the corrosion current density is ≤ 0.025 μA / cm², and the contact resistance is ≤ 2 mΩ·cm. Moreover, after 100 hours of constant potential use, the increase in the corrosion current density and contact resistance of the anode materials of the present application is significantly lower than that of the comparative examples. This shows that the anode materials prepared in the examples of the present application have better comprehensive performance.

[0163] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. An anode material, characterized in that: The invention comprises a substrate and a composite coating provided on the surface of the substrate, wherein the substrate comprises titanium or a titanium alloy; the composite coating comprises a first layer, a transition layer, a second layer and a third layer in sequence from the side close to the substrate to the side away from the substrate, wherein: The first layer comprises at least two titanium oxides, and the first layer has an oxygen content gradient that decreases away from the substrate; The transition layer comprises titanium nitride and titanium oxide, and the transition layer has a nitrogen content gradient that increases and an oxygen content gradient that decreases in a direction away from the substrate; the second layer comprising titanium nitride; The third layer comprises a catalytic material; The total thickness of the composite coating is 0.7 μm to 1.5 μm.

2. The anode material according to claim 1, characterized in that The anode material according to claim 1, characterized in that the thickness ratio of the first layer, the transition layer, the second layer, and the third layer is (1-2): (1-1.5): (8-15): (0.5-1).

3. The anode material according to claim 1, characterized in that The thickness of the first layer is 80 nm to 200 nm, and the titanium oxide in the first layer includes TiO 2 and Ti 4 O 7 .

4. The anode material according to claim 1 or 3, characterized in that The total oxygen content of the first layer is 65.0 at % to 66.0 at %.

5. The anode material according to claim 1 or 3, characterized in that The oxygen content of the first layer close to the substrate is 66.5 at % to 67.0 at %, and the oxygen content of the first layer close to the transition layer is 63.6 at % to 65.0 at %.

6. The anode material according to claim 1, characterized in that The thickness of the transition layer is 80 nm to 150 nm, and the titanium oxide in the transition layer includes one or both of TiO2 and Ti4O7.

7. The anode material according to claim 1 or 6, characterized in that The total oxygen content of the transition layer is 30 at % to 45 at %.

8. The anode material according to claim 1, characterized in that The second layer has a thickness of 500 nm to 1000 nm.

9. The anode material according to claim 1, characterized in that The thickness of the third layer is 50 nm to 100 nm.

10. The anode material according to claim 1, characterized in that The catalytic material in the third layer includes a noble metal or a noble metal alloy, and the noble metal is selected from one or more of Pt, Ir, Au, and Ru.

11. The anode material according to claim 1 or 10, characterized in that The porosity of the third layer is 25% to 50%.

12. A method for preparing the anode material according to any one of claims 1 to 11, characterized in that: include: Step 1: pre-treating the substrate surface; Step 2: In an atmosphere of a mixed gas of argon and oxygen at a pressure of 0.5 to 1.5 Pa, a first layer is prepared on the surface of the substrate by magnetron sputtering, and the proportion of oxygen in the mixed gas is gradually reduced during the magnetron sputtering process; Step 3: In an atmosphere of a mixed gas of argon, oxygen, and nitrogen at a pressure of 0.5 to 1.5 Pa, magnetron sputtering is performed on the surface of the first layer to prepare a transition layer, and during the magnetron sputtering process, the proportion of oxygen in the mixed gas is gradually reduced and the proportion of nitrogen is gradually increased; Step 4: In an atmosphere of a mixed gas of argon and nitrogen at a pressure of 0.5-1.0 Pa, a second layer is prepared on the surface of the transition layer by magnetron sputtering; Step 5: In an argon atmosphere with a pressure of 0.6-1.0 Pa, prepare a third layer on the surface of the second layer by magnetron sputtering.

13. The method according to claim 12, characterized in that The surface roughness of the pretreated substrate is 0.5 μm to 2.0 μm.

14. The method according to claim 12, characterized in that During the preparation of the first layer, the substrate temperature is 200~300℃, the power is 100~200W, the deposition rate is 0.2~0.35nm / , the oxygen flow rate in the initial stage is 15~20sccm, and the argon flow rate is 20~30sccm; in the ending stage, the oxygen flow rate is 7~15sccm, and the argon flow rate is 30~40sccm.

15. The method according to claim 12, characterized in that During the preparation of the transition layer, the substrate temperature is 250~350°C, the power is 200~300W, the deposition rate is 0.25~0.45nm / s, the oxygen flow rate in the initial stage is 15~25sccm, the nitrogen flow rate is 5~10sccm, and the argon flow rate is 30~40sccm; and the oxygen flow rate in the ending stage is 2~5sccm, the nitrogen flow rate is 20~30sccm, and the argon flow rate is 30~40sccm.

16. The method according to claim 12, characterized in that During the preparation of the second layer, the substrate temperature is 300~400℃, the power is 300~400W, the deposition rate is 0.3~0.55nm / s; the flow ratio of nitrogen and argon is 1:(2~5), and the total pressure is 0.5~1.0Pa.

17. The method according to claim 12, wherein: During the preparation of the third layer, the substrate temperature is room temperature, the power is 100-150 W, the deposition rate is 0.2-0.3 nm / s, and the argon flow rate is 20-40 sccm.

18. The method according to any one of claims 12 to 17, characterized in that After completing the preparation of any of the first layer, transition layer, or second layer, turn off the oxygen and / or nitrogen gas source, adjust the argon flow rate to 20-40 sccm, start the plasma and maintain the power at 200-300 W for 2-6 minutes, and then prepare the next layer.

19. The method according to claim 12, wherein: After the third layer is prepared, the method further includes annealing the anode material in an argon atmosphere, wherein the annealing temperature is 300-450° C. and the holding time is 1-3 hours.

20. A proton exchange membrane electrolyzer, characterized in that: The anode material comprises the anode material according to any one of claims 1 to 11.

21. A method for producing hydrogen by electrolysis of water using a proton exchange membrane, characterized in that: The anode material according to any one of claims 1 to 11 is used as the anode.

22. A method for producing hydrogen by electrolysis of water using a proton exchange membrane, characterized in that: Use the proton exchange membrane electrolyzer according to claim 20.

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