Nickel felt electrode based on modified nickel fiber, preparation method and application
The nickel felt electrodes are prepared by modifying nickel fibers, and the problem of nickel coated electrodes being easily corroded and decomposed in alkaline electrolysis of hydrogen production is solved, achieving efficient and low-cost electrode performance improvement and large-scale mass production.
Patent Information
- Application Number
- CN202510605976.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-12
- Publication Date
- 2025-08-08
AI Technical Summary
In the existing alkaline electrolytic hydrogen production technology, nickel-coated electrodes are prone to corrosion, decomposition, agglomeration and fall off under harsh environments, resulting in short service life of the electrode and limited catalytic activity. The existing improved methods are costly and difficult to mass production on a large scale.
The nickel felt electrode is prepared by modified nickel fibers, including pickling pre-activated and modification treatment of chopped nickel fibers. The fiber web is prepared by air-mbedding method and sintered at high temperature to form a nickel felt electrode.
The electrochemical active sites of the electrode are improved, production costs are reduced, and large-scale mass production is facilitated. The electrode has good consistency and high durability, avoiding the reduction of durability caused by the fall of additional components.
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Figure CN120443215A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of alkaline hydrogen production, and in particular to a nickel felt electrode based on modified nickel fiber, a preparation method and an application thereof. Background Art
[0002] Hydrogen energy is the ultimate form of clean, low-carbon energy and a key vehicle for renewable energy utilization. With the formal recognition of hydrogen energy in the Energy Law, hydrogen production from water electrolysis, particularly the production of "green hydrogen" from renewable energy-based "green electricity," will become a key upstream technology for large-scale hydrogen energy utilization.
[0003] Alkaline water electrolysis solutions have been proven for many years and have mature processes, making them the preferred choice for large-scale engineering applications. The catalytic electrode is the core of the electrolysis reaction and determines the rated point design and even the overall scale matching of the hydrogen production equipment. In current alkaline electrolysis technology, alkaline electrolyzers conventionally use nickel mesh and nickel foam as catalytic electrodes. To improve performance, nickel-aluminum alloy is usually sprayed on the surface of the nickel mesh or nickel foam, and then the aluminum is removed by corrosion to obtain a Raney nickel coating to increase the active area of the electrode. To further improve the performance and service life of the Raney nickel-coated electrode, the formulation and treatment process of the Raney nickel coating have been continuously optimized. However, due to the harsh working environment of the alkaline electrolyzer, the electrodes are prone to corrosion, decomposition, agglomeration, and shedding under the influence of high temperature, high pressure, high flow of strong alkaline electrolyte, and start-stop reverse current. As a result, the durability of the Raney nickel-coated electrode has a limited upper limit, the electrode service life is not high, and the catalytic activity of the electrode is limited. In order to improve the performance of the electrode and extend the service life of the electrode, various methods have been further tried in the existing technology, such as developing new oxygen evolution electrodes or doping transition metal alloys or precious metals into nickel electrodes or directly using precious metal electrodes. However, these methods are expensive and cannot be used for large-scale mass production. Summary of the Invention
[0004] In order to solve the problems in the prior art, the present application provides a nickel felt electrode based on modified nickel fiber, a preparation method and an application, which improves the electrochemical structural sites on the surface of the nickel fiber and reduces the production cost of electrodes containing high electrochemical structural sites, thereby facilitating large-scale mass production.
[0005] The first aspect of the present application is to provide a method for preparing a nickel felt electrode based on modified nickel fiber, using the following technical solution: A method for preparing a nickel felt electrode based on modified nickel fiber comprises the following steps: S1, immersing the chopped nickel fibers in an inorganic acid solution for pickling and pre-activation; S2, filtering out the pre-activated chopped nickel fibers and immersing them in a modification solution for modification; S3, cleaning and drying the modified chopped nickel fibers; S4, using an air-laid method to loosen and lay the chopped nickel fibers obtained in step S3 into a fiber web; S5, stacking at least two layers of the prepared fiber web, rolling and flattening the web, and then drying the multi-layer fiber web; S6. Sintering the dried multi-layer fiber mesh at a high temperature to obtain nickel fiber felt; S7. Roll and flatten the nickel fiber felt to obtain a nickel felt electrode.
[0006] In a preferred embodiment, the inorganic acid solution is one or more of phosphoric acid, sulfuric acid, nitric acid, and hydrochloric acid, and the molar concentration of the inorganic acid solution is 2M-5M.
[0007] In a preferred embodiment, the soaking time of the chopped nickel fibers in step S1 is 2-10 minutes.
[0008] In a preferred embodiment, the modifying solution consists of an inorganic acid solution and an iron salt solution, wherein the molar concentration of the inorganic acid solution is 2M-5M, and the molar concentration of the iron salt solution is 0.5M-1.5M.
[0009] In a preferred embodiment, the immersion time of the pre-activated chopped nickel fibers in step S2 is 10-30 seconds.
[0010] In a preferred embodiment, the surface density of the fiber web in step S4 is 200-400 g / m 2 .
[0011] In a preferred embodiment, each layer of the multi-layer fiber web is a fiber web of the same specification or different specifications, and the drying temperature in step S5 is 150-200°C.
[0012] In a preferred embodiment, the sintering temperature in step S6 is 1000-1500° C., the pressure is 0.1-0.5 MPa, and the sintering time is 1-5 h.
[0013] The second invention of the present application is to provide a nickel felt electrode obtained by the preparation method of the nickel felt electrode based on modified nickel fiber as described above.
[0014] The third aspect of the present application is to provide a nickel felt electrode based on modified nickel fiber for use in the field of water electrolysis and hydrogen production, including but not limited to use as an electrode for water electrolysis and oxygen evolution in an alkaline system.
[0015] In summary, this application has the following beneficial effects: 1. The process of the present application is simple and easy to mass produce. Compared with the mature fiber mat preparation process, it only requires the introduction of fiber pre-activation and modification treatment in the fiber decomposition / opening stage, which is easy to operate.
[0016] 2. The process cost of this application is low and the consistency of the electrode is good. Compared with conventional nickel fibers, the short-cut nickel fibers of this application have a higher specific surface area structure after chemical modification, thus having more electrochemically active sites. Compared with the treatment of fiber felt, the modification of nickel fibers can ensure that the final electrode is more uniform, thereby achieving consistent high performance. In addition, the cost of the fiber modification treatment of this application is about 20% lower than that of the fiber felt modification treatment, which is more conducive to large-scale mass production.
[0017] 3. Good durability: Since the nickel electrode obtained in this application does not contain any additional components, there is no risk of reduced electrode durability due to the loss of additional components.
[0018] 4. Compared with the processing technology for sheet-type and roll-to-roll pressing products, the process of this application is a reactor-type processing technology for raw materials. The processing method is more intensive and the requirements for processing equipment are reduced, thereby greatly reducing costs.
[0019] 5. This application controls the structure, porosity and thickness of the electrode by simply adjusting the specifications of different layers of nickel felt fibers, thereby achieving process optimization according to different practical applications. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 This is a flow chart of the preparation process of the nickel felt electrode of Example 1 of the present application. DETAILED DESCRIPTION
[0021] The following combination Figure 1 The present invention is further described in detail in the following examples. All reagents without manufacturer's name are commercially available conventional reagents.
[0022] Example 1 A method for preparing a nickel felt electrode based on modified nickel fiber comprises the following steps: S1, immersing short-cut nickel fibers with a diameter of 10 μm and a length of 20 mm in a 2 M phosphoric acid solution for acid washing and pre-activation for 3 min; S2, filtering the pre-activated chopped nickel fibers and immersing them in a modification solution composed of a mixture of 2M hydrochloric acid and 1.5M ferric phosphate solution in a volume ratio of 1:1 for 30 seconds; S3, cleaning and drying the modified chopped nickel fibers; S4, using the air-laid method, the short-cut nickel fibers obtained in step S3 were opened and laid to form a net with a surface density of 300 g / m 2 fiber web; S5, stacking the obtained fiber web in four layers, rolling and fixing them flat, and then drying them at 150°C; S6, sintering the dried multilayer fiber web at a temperature of 1000° C. and a pressure of 0.4 MPa for 5 h, and then cooling to obtain a nickel fiber felt; S7. Roll the nickel fiber felt to 3 mm to obtain a nickel felt electrode.
[0023] Example 2 A method for preparing a nickel felt electrode based on modified nickel fiber comprises the following steps: S1, immersing short-cut nickel fibers with a diameter of 15 μm and a length of 40 mm in a hydrochloric acid solution with a molar concentration of 4 M for pickling and pre-activation for 2 minutes; S2, filtering the pre-activated chopped nickel fibers, removing them from the filter, and immersing them in a modification solution consisting of a mixture of a 4M hydrochloric acid solution and a 0.5M ferric chloride solution in a volume ratio of 1:1 for 20 seconds; S3, cleaning and drying the modified chopped nickel fibers; S4, using the air-laid method, the chopped nickel fibers obtained in step S3 were opened and laid to form a mesh with a surface density of 250 g / m 2 fiber web; S5, stacking the prepared fiber web in three layers, rolling it to make it flat, and then drying it at 200°C; S6, sintering the dried multilayer fiber web at a temperature of 1200° C. and a pressure of 0.3 MPa for 3 h, and then cooling the resulting nickel fiber felt; S7. Roll the nickel fiber felt to 2 mm to obtain a nickel felt electrode.
[0024] Example 3 A method for preparing a nickel felt electrode based on modified nickel fiber comprises the following steps: S1, immersing short-cut nickel fibers with a diameter of 25 μm and a length of 30 mm in a nitric acid solution with a molar concentration of 3 M for acid washing and pre-activation for 3 minutes; S2, filtering the pre-activated chopped nickel fibers and immersing them in a modification solution consisting of a mixture of a 3M nitric acid solution and a 1.0M ferric nitrate solution in a volume ratio of 1:1 for 25 seconds; S3, cleaning and drying the modified chopped nickel fibers; S4, using the air-laid method, the chopped nickel fibers obtained in step S3 were opened and laid to form a sheet with a surface density of 350 g / m 2 fiber web; S5, stacking the prepared fiber web in three layers, rolling it to fix it flat, and then drying it at 150°C; S6, sintering the dried multilayer fiber web at a temperature of 1250° C. and a pressure of 0.3 MPa for 4 h, and then cooling the sintered web to obtain a nickel fiber felt; S7. Roll the nickel fiber felt to 2 mm to obtain a nickel felt electrode.
[0025] Example 4 A method for preparing a nickel felt electrode based on modified nickel fiber comprises the following steps: S1, immersing short-cut nickel fibers with a diameter of 30 μm and a length of 25 mm in a 4 M sulfuric acid solution for acid washing and pre-activation for 2 min; S2, filtering the pre-activated chopped nickel fibers and immersing them in a modification solution consisting of a mixture of a 4M sulfuric acid solution and a 0.5M ferric sulfate solution in a volume ratio of 1:1 for 20 seconds; S3, cleaning and drying the modified chopped nickel fibers; S4, using the air-laid method, the short-cut nickel fibers obtained in step S3 were opened and laid to form a net with a surface density of 400 g / m 2 fiber web; S5, stacking two layers of the prepared fiber web, rolling them to fix them flat, and then drying them at 180°C; S6, sintering the dried multilayer fiber web at a temperature of 1500° C. and a pressure of 0.5 MPa for 3 h, and then cooling the resulting nickel fiber felt; S7. Roll the nickel fiber felt to 3 mm to obtain a nickel felt electrode.
[0026] Example 5 A method for preparing a nickel felt electrode based on modified nickel fiber comprises the following preparation steps: randomly stacking one layer of the fiber mesh prepared in Examples 1-4, rolling and fixing them flat, and then drying them at 150°C, and then hot-pressing and sintering the multi-layer fiber mesh. The sintering temperature is 1000°C, and the sintering pressure is 0.4 MPa. After high-temperature sintering for 5 hours, the temperature is lowered and the nickel fiber adhesive is taken out, and the nickel fiber felt is rolled to 3 mm to obtain a nickel felt electrode.
[0027] Comparative Example 1 A method for preparing a nickel felt electrode based on modified nickel fiber comprises the following steps: S1, immersing short-cut nickel fibers with a diameter of 10 μm and a length of 20 mm in a 2 M phosphoric acid solution for acid washing and pre-activation for 3 minutes, and then washing and drying; S2, using the air-laid method, the chopped nickel fibers obtained in step S1 were opened and laid to form a sheet with a surface density of 300 g / m 2 fiber web; S3, stacking the obtained fiber web in four layers, rolling it to fix it flat, and then drying it at 150°C; S4, sintering the dried multilayer fiber web at a temperature of 1000° C. and a pressure of 0.4 MPa for 5 h, and then cooling the resulting nickel fiber felt; S5. Roll the nickel fiber felt to 3 mm to obtain a nickel felt electrode.
[0028] Comparative Example 2 A method for preparing a nickel felt electrode based on modified nickel fiber comprises the following steps: S1, washing and drying short-cut nickel fibers with a diameter of 10 μm and a length of 20 mm; S2, using the air-laid method, the chopped nickel fibers obtained in step S1 were opened and laid to form a sheet with a surface density of 300 g / m 2 fiber web; S3, stacking the obtained fiber web in four layers, rolling it to fix it flat, and then drying it at 150°C; S4, sintering the dried multilayer fiber web at a temperature of 1000° C. and a pressure of 0.4 MPa for 5 h, and then cooling the resulting nickel fiber felt; S5. Roll the nickel fiber felt to 3 mm to obtain a nickel felt electrode.
[0029] Comparative Example 3 A 46-mesh nickel mesh with a thickness of 0.5 mm was used to plasma spray a nickel-aluminum alloy powder with a mass ratio of 8:2. The powder was then placed in a potassium hydroxide solution with a molar concentration of 3 M and soaked at 40 ° C for 24 h to obtain a tape loading of 250 g / m 2 Porous Raney nickel-coated nickel mesh electrode.
[0030] Performance Testing The nickel felt electrodes obtained in Examples 1-5 and Comparative Example 1 were tested for porosity and specific surface area, with the results shown in Table 1. A standard three-electrode system was also used to simulate actual operating conditions for Examples 1, Comparative Examples 2, and 3. Aging tests were conducted using a standard three-electrode system. The working electrode was the test sample, the counter electrode was a 3cm*3cm nickel plate, and the reference electrode was a Hg / HgO electrode. The electrolyte was 30% KOH, and the temperature was 80°C. The electrodes were operated continuously for 168 hours at an oxygen evolution overpotential of 350mV. The current change was monitored and the decay rate was calculated. The test results are shown in Table 2.
[0031] Table 1 Nickel felt electrode porosity and specific surface area test results project Porosity% <![CDATA[Specific surface area cm 2 / cm 3 > Example 1 94.9％ 185 Example 2 94.8％ 190 Example 3 93.7％ 230 Example 4 95.7％ 155 Example 5 94.1％ 215 Comparative Example 1 95.1％ 118 Comparative Example 2 94.8％ 105 As can be seen from Table 1, the specific surface areas of the nickel felt electrodes obtained in Examples 1-5 of the present application are much larger than the specific surface areas of the nickel felt electrodes obtained in Comparative Examples 1-2, indicating that after the nickel fiber is modified in the present application, the nickel felt electrodes have more electrochemically active sites.
[0032] Table 2 Electrode oxygen evolution overpotential and electrochemical decay test results project <![CDATA[Oxygen evolution overpotential V @ 2500 A / m 2 > Electrochemical decay rate after accelerated aging % Example 1 0.13 0.7 Comparative Example 1 0.18 1.0 Comparative Example 2 0.20 1.0 Comparative Example 3 0.19 2.0 It can be seen from Table 2 that the oxygen evolution overpotential of the nickel electrode obtained in Example 1 of the present application is lower than the oxygen evolution overpotential of the nickel electrodes in Comparative Examples 1 to 3, and the electrochemical decay rate after accelerated aging is also much lower than that of the nickel electrodes in Comparative Examples 1 to 3, indicating that the performance of the nickel electrode obtained in Example 1 of the present application is better than that of Comparative Examples 1 to 3.
[0033] The embodiments of this specific implementation method are all preferred embodiments of the present application and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.
Claims
1. A method for preparing a nickel felt electrode based on modified nickel fiber, characterized in that: The method comprises the following preparation steps: S1, immersing the chopped nickel fibers in an inorganic acid solution for pickling and pre-activation; S2, filtering out the pre-activated chopped nickel fibers and immersing them in a modification solution for modification; S3, cleaning and drying the modified chopped nickel fibers; S4, opening and laying the chopped nickel fibers obtained in step S3 to prepare a fiber web; S5, stacking at least two layers of the prepared fiber web, rolling them to fix and flatten them, and then drying the multi-layer fiber web; S6. Sintering the dried multi-layer fiber web at a high temperature to obtain nickel fiber felt; S7. Roll and flatten the nickel fiber felt to obtain a nickel felt electrode.
2. The method for preparing a nickel felt electrode based on modified nickel fiber according to claim 1, characterized in that: The inorganic acid solution is one or more of phosphoric acid, sulfuric acid, nitric acid, and hydrochloric acid, and the molar concentration of the inorganic acid solution is 2M-5M.
3. The method for preparing a nickel felt electrode based on modified nickel fiber according to claim 1, characterized in that: The soaking time of the chopped nickel fibers in step S1 is 2-10 minutes.
4. The method for preparing a nickel felt electrode based on modified nickel fiber according to claim 1, characterized in that: The modifying solution consists of an inorganic acid solution and an iron salt solution, wherein the molar concentration of the inorganic acid solution is 2M-5M, and the molar concentration of the iron salt solution is 0.5M-1.5M.
5. The method for preparing a nickel felt electrode based on modified nickel fiber according to claim 1, characterized in that: The immersion time of the pre-activated chopped nickel fibers in step S2 is 10-30 seconds.
6. The method for preparing a nickel felt electrode based on modified nickel fiber according to claim 1, characterized in that: The surface density of the fiber web in step S4 is 200-400 g / m 2 .
7. The method for preparing a nickel felt electrode based on modified nickel fiber according to claim 1, characterized in that: Each layer of the multi-layer fiber web is a fiber web of the same specification or different specifications, and the drying temperature in step S5 is 150-200°C.
8. The method for preparing a nickel felt electrode based on modified nickel fiber according to claim 1, characterized in that: The sintering temperature in step S6 is 1000-1500° C., the pressure is 0.1-0.5 MPa, and the sintering time is 1-5 hours.
9. A nickel felt electrode obtained by the method for preparing a nickel felt electrode based on modified nickel fiber according to any one of claims 1 to 8.
10. An application of the nickel felt electrode based on modified nickel fiber as claimed in claim 9 in the field of hydrogen production by water electrolysis, including but not limited to use as an electrode for oxygen evolution by water electrolysis in an alkaline system.