A double-layer electrode suitable for fluctuating working conditions of alkaline electrolysis water and a preparation method thereof
By constructing a bilayer structure of porous Raney nickel and nano-nickel heterojunction catalyst layer on the alkaline water electrolysis electrode, the stability and activity problems of the electrode under fluctuating operating conditions were solved, and an efficient and stable alkaline water electrolysis hydrogen production process was realized.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- YANGZHOU POLYTECHNIC COLLEGE
- Filing Date
- 2026-05-28
- Publication Date
- 2026-07-31
AI Technical Summary
Existing alkaline water electrolysis hydrogen production electrodes suffer from problems such as catalyst shedding, activity decay, and structural failure under fluctuating operating conditions, and lack high activity, strong binding force, and stability to withstand reverse current.
A bilayer electrode structure is adopted, consisting of a porous mesh substrate and a porous Raney nickel catalyst layer coated with a nano-nickel heterojunction catalyst layer. Combined with plasma thermal spraying and sintering processes, a Ni/NiO heterojunction catalyst layer with high roughness and strong adhesion is formed, which enhances the stability and activity of the electrode.
It achieves high activity (low hydrogen evolution overpotential), high binding force (low weight loss rate) and ultra-stability (no decay after 1000h), and is suitable for alkaline water electrolysis to produce hydrogen under fluctuating operating conditions. It is compatible with photovoltaic/wind power fluctuations and is suitable for megawatt-level electrolyzers.
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Figure CN122484801A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of electrode materials for alkaline water electrolysis to produce hydrogen, specifically to a double-layer electrode suitable for alkaline water electrolysis under fluctuating operating conditions and its preparation method. Background Technology
[0002] Alkaline water electrolysis (AWE) is the mainstream technology for large-scale production of green hydrogen, with advantages such as low cost, non-precious metal catalysts, and megawatt-scale scale-up capability. However, under fluctuating renewable energy power supply such as photovoltaic and wind power, frequent start-ups and shutdowns of the electrolyzer generate reverse currents. These reverse currents can easily lead to repeated oxidation and reduction at the cathode, resulting in problems such as catalyst shedding, activity decay, and structural failure.
[0003] Existing technologies have the following drawbacks: traditional nickel electrodes have insufficient hydrogen evolution activity and high overpotential under high current density; highly active electrodes such as NiMo are prone to Mo leaching under alkaline conditions and reverse current, resulting in poor stability; the direct deposition of Ni / NiO layers has weak adhesion to the nickel mesh substrate, making them prone to cracking, delamination, and detachment; and there is a lack of industrially viable electrodes that can simultaneously meet the requirements of high activity, strong adhesion, resistance to reverse current, and long-term stability. Summary of the Invention
[0004] To address the aforementioned technical problems, this invention proposes a double-layer electrode suitable for alkaline water electrolysis under fluctuating operating conditions and its preparation method.
[0005] The technical problem to be solved by this invention is achieved by the following technical solution: A double-layer electrode suitable for alkaline water electrolysis under fluctuating operating conditions includes: The electrode substrate is a porous mesh, serving as a supporting substrate; The catalyst layer, coated on the electrode substrate, includes a porous Raney nickel catalyst layer for improving high roughness and strong adhesion, and a nano-nickel heterojunction catalyst layer for enhancing activity and corrosion resistance.
[0006] Preferably, the electrode substrate is made of one of nickel, stainless steel, or titanium.
[0007] Preferably, the mesh of the electrode substrate has a plain or twill structure.
[0008] Preferably, the electrode substrate has a wire diameter of 0.1μm to 0.25μm and a mesh size of 30 to 60 mesh.
[0009] A method for preparing a double-layer electrode suitable for alkaline water electrolysis under fluctuating operating conditions, comprising the following steps: Step S1, Preprocessing: The electrode substrate is cut to the required size and cleaned with weak acid and water in sequence. After cleaning, the surface is roughened by sandblasting. Step S2, Electrode spraying: Nickel-aluminum powder was sprayed onto the pretreated electrode substrate using a plasma thermal spraying process. Step S3, Post-processing: The coated electrode substrate is immersed in a 10%–30% KOH solution and reacted for 2–10 hours to remove aluminum from the electrode substrate, thereby obtaining a porous Raney nickel electrode with a porous Raney nickel catalyst layer attached. Step S4, Preparation of nano-nickel electrode paste: The electrode precursor was dissolved in a solvent, and template agent and ammonia were added. The mixture was stirred until homogeneous to form a stable nickel precursor solution. Step S5: Coating and sintering of nano-nickel electrodes: A porous Raney nickel electrode is immersed in a nickel precursor solution for coating. The coated electrode is first dried in an oven for 2 to 6 hours, and then sintered in a muffle furnace at 250°C to 350°C for 2 to 4 hours. Finally, it is sintered in a 10 vol% H2 / Ar mixed gas stream at 200°C to 300°C for 0.5 to 3 hours to obtain a nano-nickel multilayer electrode with a porous Raney nickel catalyst layer and a nano-nickel heterojunction catalyst layer attached. Step S6, Interface Enhancement: Heat treatment was performed on the nano-nickel multilayer electrode with porous Raney nickel catalyst layer and nano-nickel heterojunction catalyst layer attached to enhance the bonding force between catalyst layers and eliminate internal stress.
[0010] Furthermore, the process parameters for the plasma thermal spraying process in step S2 are: gun distance 80mm~140mm, powder feeding rate 60g / min~150g / min, and current 600A~900A.
[0011] Furthermore, the electrode precursor is one or more of nickel nitrate, nickel chloride, and nickel sulfate.
[0012] 8. The method for preparing a double-layer Ni+NiNiO electrode for water electrolysis under fluctuating operating conditions according to claim 5, characterized in that: the solvent is one or more of ethanol, propanol, isopropanol, and n-butanol.
[0013] Furthermore, the template agent is one or more of polyethylene glycol, triblock copolymer, and hexadecyltrimethylammonium bromide.
[0014] Furthermore, the molar ratio of electrode precursor, solvent, template agent, and ammonia is 1:4-50:0.01-0.2:2-20.
[0015] The beneficial effects of this invention are: This invention has: High activity: the hydrogen evolution overpotential is only 238mV at 500mA / cm², which is superior to pure Ni and NiMo electrodes; High bonding strength: The ultrasonic weight loss rate is only 1.2%, far lower than that of traditional electrodes; Ultra-stable: No attenuation after 1000 hours of constant current testing, and the activity remains basically unchanged after 100 reverse current cycles; Fluctuation Resistance: Compatible with fluctuating power supplies from photovoltaics / wind power, it does not degrade with frequent start-stop cycles; Low cost: All non-precious metal system, process can be scaled up, and it is compatible with megawatt-level electrolytic cells. Attached Figure Description
[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a surface morphology diagram of a pure Ni electrode; Figure 2 SEM surface morphology of the bilayer Ni+Ni / NiO electrode; Figure 3 This is a SEM cross-sectional view of a double-layer Ni+Ni / NiO electrode. Figure 4 Initial LSV curves for four types of electrodes: Ni, Ni / NiO, NiMO, and bilayer Ni+Ni / NiO; Figure 5 The graph shows the changes in the LSV curve of the NiMO electrode after constant current and reverse current tests. Figure 6 The graph shows the LSV curve changes of the double-layer Ni+Ni / NiO electrode after constant current and reverse current tests. Figure 7 This is a schematic diagram of reverse current testing of a double-layer Ni+Ni / NiO electrode. Figure 8 The graph shows the changes in the LSV curve of the NiMO electrode after constant current and reverse current tests. Figure 9 This is a schematic diagram of a reverse current impact test on a Ni electrode. Figure 10 The graph shows the changes in LSV curves of the Ni / NiO electrode after constant current and reverse current tests. Figure 11 This is a schematic diagram of a reverse current impact test for a Ni / NiO electrode. Figure 12 Schematic diagram of reverse current impact test of NiMO electrode; Figure 13 A schematic diagram of the daily power curve of a double-layer Ni+Ni / NiO electrode applied in a photovoltaic hydrogen production system; Figure 14 This is a schematic diagram of the IV characteristic curves of a double-layer Ni+Ni / NiO electrode in a 10kW electrolytic cell. Detailed Implementation
[0017] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with the accompanying drawings and embodiments.
[0018] A bilayer electrode suitable for alkaline water electrolysis under fluctuating operating conditions includes an electrode substrate and a catalyst layer coated on the electrode substrate. The electrode substrate serves as a supporting base, and the catalyst layer includes a porous Raney nickel catalyst layer and a nano-nickel heterojunction catalyst layer. The porous Raney nickel catalyst layer serves as the bottom layer, which improves the surface roughness and bonding strength, while the nano-nickel heterojunction catalyst layer serves as the top layer, which enhances the activity and corrosion resistance.
[0019] Furthermore, the electrode substrate is a porous mesh, made of one of nickel, stainless steel, or titanium. In this embodiment, a nickel substrate is selected as the electrode substrate. The porous mesh has a plain or twill weave structure, with a wire diameter of 0.1 μm to 0.25 μm and a mesh count of 30 to 60 mesh.
[0020] This invention proposes and constructs an integrated bilayer Ni+Ni / NiO heterojunction electrode by thermal spraying and sintering. The heterojunction structure can construct a Ni / NiO↔Ni(OH)2 redox couple with stronger reversibility, improving the structural stability of the material under reverse current. At the same time, the nanoscale Ni / NiO electrode also exhibits better catalytic performance and shows a lower hydrogen evolution overpotential.
[0021] A method for preparing a double-layer Ni+NiNiO electrode for water electrolysis under fluctuating operating conditions, comprising the following steps: Step S1, Preprocessing: The electrode substrate is cut to the required size, which in this embodiment is 10mm to 2000mm. It is then cleaned successively with a weak acid and water, followed by sandblasting for surface roughening.
[0022] Step S2, Electrode spraying: Nickel-aluminum powder was sprayed onto a pretreated electrode substrate using a plasma thermal spraying process. The plasma thermal spraying process parameters were: gun distance 80mm–140mm, powder feed rate 60g / min–150g / min, and current 600A–900A. Figure 1 The figure shows the surface morphology of a pure Ni electrode. As can be seen from the figure, no obvious nickel particles were observed on the electrode after spraying, indicating that the spraying power was appropriate and the nickel catalyst layer completely covered the substrate.
[0023] Step S3, Post-processing: The coated electrode substrate is immersed in a 10%–30% KOH solution and reacted for 2–10 hours to remove aluminum from the electrode substrate, resulting in a porous Raney nickel electrode with a porous Raney nickel catalyst layer. The porous Raney nickel catalyst layer can improve the adhesion of the nano-nickel heterojunction catalyst layer and reduce detachment and mass loss.
[0024] Step S4, Preparation of nano-nickel electrode paste: The electrode precursor is dissolved in a solvent, and a template agent and ammonia are added and stirred until homogeneous to form a stable nickel precursor solution. Specifically, the electrode precursor is one or more of nickel nitrate, nickel chloride, and nickel sulfate; the solvent is one or more of ethanol, propanol, isopropanol, and n-butanol; the template agent is one or more of polyethylene glycol, triblock copolymer, and hexadecyltrimethylammonium bromide; and the molar ratio of electrode precursor, solvent, template agent, and ammonia is 1:4–50:0.01–0.2:2–20.
[0025] In this embodiment, nickel nitrate solution is used as the electrode precursor, ethanol is used as the solvent, and polyethylene glycol is used as the template agent.
[0026] Step S5: Coating and sintering of nano-nickel electrodes: A porous Raney nickel electrode is immersed in a nickel precursor solution for coating. The coated electrode is first dried in an oven for 2 to 6 hours, and then sintered in a muffle furnace at 250°C to 350°C for 2 to 4 hours. Finally, it is sintered in a 10 vol% H2 / Ar mixed gas stream at 200°C to 300°C for 0.5 to 3 hours to obtain a nano-nickel multilayer electrode with a porous Raney nickel catalyst layer and a nano-nickel heterojunction catalyst layer attached.
[0027] Step S6, Interface Enhancement: Heat treatment was performed on a nano-nickel multilayer electrode with an attached porous Raney nickel catalyst layer and a nano-nickel heterojunction catalyst layer to enhance the interlayer bonding force, eliminate internal stress, and improve structural stability. For example... Figure 2 and Figure 3 As shown, after coating the surface of the motor substrate with a nano-nickel heterojunction catalytic layer, the nano-nickel heterojunction catalytic layer completely covers the nickel electrode and has good adhesion to the electrode substrate.
[0028] Furthermore, to verify the effect, four types of electrodes—pure Ni electrode, NiMo electrode, Ni / NiO electrode, and the bilayer Ni+NiNiO electrode prepared in this invention—were tested and compared.
[0029] like Figure 4 The figure shows the initial LSV curves for four types of electrodes: Ni, Ni / NiO, NiMO, and bilayer Ni+Ni / NiO.
[0030] like Figure 5The figure shows the LSV curve changes of the NiMO electrode after constant current and reverse current tests. The LSV curves after constant current and reverse current tests are at 5000 A / m. 2 At that time, the potential increased significantly, and ultrasonic testing showed a large weight loss rate, indicating poor stability of the surface NiMo electrode.
[0031] like Figure 6 The figure shows the LSV curve changes of the bilayer Ni+Ni / NiO electrode after constant current and reverse current tests. As can be seen from the figure, the LSV curves of the electrode remain essentially unchanged after the constant current and reverse current tests, indicating excellent surface electrode stability.
[0032] like Figure 7 The diagram shown is a schematic of a reverse current test for a double-layer Ni+Ni / NiO electrode.
[0033] like Figure 8 The figure shows the LSV curve changes of the NiMO electrode after constant current test and reverse current test.
[0034] like Figure 9 The diagram shown is a schematic of a reverse current impact test on a Ni electrode.
[0035] like Figure 10 The figure shows the LSV curve changes of the Ni / NiO electrode after constant current test and reverse current test.
[0036] like Figure 11 The diagram shown is a schematic of a reverse current impact test on a Ni / NiO electrode.
[0037] like Figure 12 The diagram shown is a schematic of a reverse current impact test on a NiMO electrode.
[0038] The table below shows a comparison of the performance data of various electrodes:
[0039] The electrodes prepared according to this invention are applied to alkaline electrolyzers and photovoltaic hydrogen production: 20 electrodes with a diameter of 20 cm are assembled into 20 sections of a 10 kW alkaline electrolyzer, which are directly coupled to a photovoltaic power source for operation at a current density of 2000 A / m. 2 -6000A / m 2 Within this range, the cell voltage is 1.542V-1.772V, and the energy consumption is 4.2kWh / Nm³. 3 .like Figure 13 and Figure 14 As shown, after three months of continuous operation under fluctuating conditions, the IV curve of the electrolyzer showed no significant deterioration, demonstrating excellent stability.
[0040] This invention provides a method for preparing a double-layer Ni+NiNiO electrode for water electrolysis. By roughening the bottom layer and strengthening the interface bonding through heat treatment, an extremely low weight loss rate is achieved. It can achieve no significant performance degradation under reverse current and fluctuating start-stop conditions. It can be directly used in alkaline electrolyzers of 10kW and above, and there is no potential rise after 3 months of continuous operation.
[0041] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely prisms of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.
Claims
1. A double-layer electrode suitable for alkaline water electrolysis under fluctuating operating conditions, characterized in that: include: The electrode substrate is a porous mesh, serving as a supporting substrate; The catalyst layer, coated on the electrode substrate, includes a porous Raney nickel catalyst layer for improving high roughness and strong adhesion, and a nano-nickel heterojunction catalyst layer for enhancing activity and corrosion resistance.
2. The double-layer electrode for alkaline water electrolysis under fluctuating operating conditions according to claim 1, characterized in that: The electrode substrate is made of one of the following materials: nickel, stainless steel, or titanium.
3. The double-layer electrode for alkaline water electrolysis under fluctuating operating conditions according to claim 1, characterized in that: The electrode substrate has a plain or twill mesh structure.
4. A double-layer electrode suitable for alkaline water electrolysis under fluctuating operating conditions according to claim 1, characterized in that: The electrode substrate has a wire diameter of 0.1μm to 0.25μm and a mesh size of 30 to 60 mesh.
5. A method for preparing a double-layer electrode suitable for alkaline water electrolysis under fluctuating operating conditions, characterized in that: The preparation of a bilayer electrode suitable for alkaline water electrolysis under fluctuating operating conditions, as described in any one of claims 1 to 4, comprises the following steps: Step S1, Preprocessing: The electrode substrate is cut to the required size and cleaned with weak acid and water in sequence. After cleaning, the surface is roughened by sandblasting. Step S2, Electrode spraying: Nickel-aluminum powder was sprayed onto the pretreated electrode substrate using a plasma thermal spraying process. Step S3, Post-processing: The coated electrode substrate is immersed in a 10%–30% KOH solution and reacted for 2–10 hours to remove aluminum from the electrode substrate, thereby obtaining a porous Raney nickel electrode with a porous Raney nickel catalyst layer attached. Step S4, Preparation of nano-nickel electrode paste: The electrode precursor was dissolved in a solvent, and template agent and ammonia were added. The mixture was stirred until homogeneous to form a stable nickel precursor solution. Step S5: Coating and sintering of nano-nickel electrodes: A porous Raney nickel electrode is immersed in a nickel precursor solution for coating. The coated electrode is first dried in an oven for 2 to 6 hours, and then sintered in a muffle furnace at 250°C to 350°C for 2 to 4 hours. Finally, it is sintered in a 10 vol% H2 / Ar mixed gas stream at 200°C to 300°C for 0.5 to 3 hours to obtain a nano-nickel multilayer electrode with a porous Raney nickel catalyst layer and a nano-nickel heterojunction catalyst layer attached. Step S6, Interface Enhancement: Heat treatment was performed on the nano-nickel multilayer electrode with porous Raney nickel catalyst layer and nano-nickel heterojunction catalyst layer attached to enhance the bonding force between catalyst layers and eliminate internal stress.
6. The method for preparing a double-layer electrode suitable for alkaline water electrolysis under fluctuating operating conditions according to claim 5, characterized in that: The process parameters for plasma thermal spraying in step S2 are: gun distance 80mm~140mm, powder feeding rate 60g / min~150g / min, and current 600A~900A.
7. The method for preparing a double-layer electrode suitable for alkaline water electrolysis under fluctuating operating conditions according to claim 5, characterized in that: The electrode precursor is one or more of nickel nitrate, nickel chloride, and nickel sulfate.
8. The method for preparing a double-layer electrode suitable for alkaline water electrolysis under fluctuating operating conditions according to claim 5, characterized in that: The solvent is one or more of ethanol, propanol, isopropanol, and n-butanol.
9. The method for preparing a double-layer electrode suitable for alkaline water electrolysis under fluctuating operating conditions according to claim 5, characterized in that: The template agent is one or more of polyethylene glycol, triblock copolymer, and hexadecyltrimethylammonium bromide.
10. The method for preparing a double-layer electrode suitable for alkaline water electrolysis under fluctuating operating conditions according to claim 5, characterized in that: The molar ratio of electrode precursor, solvent, template agent, and ammonia is 1:4-50:0.01-0.2:2-20.