Hydrogen electrode, method for producing the same, and use thereof
By introducing hydrophobic conductive fiber materials into the nickel-based catalyst layer to form a conductive hydrophobic network, the problems of low activity and easy flooding of nickel-based catalysts are solved, achieving high-efficiency hydrogen electrode performance and low-cost hydrogen battery applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- UNIV OF SCI & TECH OF CHINA
- Filing Date
- 2023-03-24
- Publication Date
- 2026-04-17
AI Technical Summary
Existing nickel-based catalysts have low mass activity, resulting in excessively thick catalyst layers that are easily submerged by the electrolyte, affecting the catalytic performance and operating current density of hydrogen batteries.
Introducing hydrophobic conductive fiber materials into the nickel-based catalyst layer forms a conductive hydrophobic network, providing hydrogen transport channels, reducing competition between hydrogen and water, and improving catalytic activity.
It improves the conductivity and catalytic activity of the hydrogen electrode, alleviates the agglomeration of nickel-based catalysts, significantly improves electrochemical performance, and reduces the stack cost of the battery.
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Figure CN116387532B_ABST
Abstract
Description
Technical Field
[0001] This disclosure pertains to the field of energy storage, and particularly relates to a hydrogen electrode and its preparation method and a nickel-metal hydride battery, especially a low-cost HER / HOR dual-function hydrogen electrode and its preparation method and its application in nickel-metal hydride batteries. Background Technology
[0002] The transition from traditional fossil fuels to renewable energy is underway. Grid-scale battery energy storage technology plays a crucial role in integrating intermittent wind and solar power into the grid. However, most battery technologies, such as lithium-ion batteries, vanadium redox flow batteries, and lead-acid batteries, fail to meet the requirements for high safety, low cost, and long lifespan. In recent years, hydrogen batteries, especially nickel-metal hydride batteries, have proven to have ultra-long lifespan and high safety, showing great potential for grid-scale battery energy storage. A significant feature of hydrogen batteries is that the anode reaction is a bifunctional reversible catalytic reaction of HER (hydrogen evolution reaction) / HOR (hydrogen oxidation reaction), exhibiting good stability and durability compared to commercially expensive catalysts (such as Pt). Therefore, developing electrodes with inexpensive nickel-based catalysts to replace traditional commercial Pt electrodes is of great importance.
[0003] To date, although Ni-based catalysts have exhibited good bifunctional reversible catalytic activity for HER / HOR as a non-noble metal catalyst, the mass activity of most Ni-based catalysts is still far lower than that of Pt catalysts. Therefore, the mass loading of Ni-based catalysts often needs to be hundreds or even thousands of times higher than that of Pt-based metal (PGM) catalysts to achieve performance comparable to Pt catalysts. This results in a much thicker catalyst layer for non-noble metal Ni HER / HOR gas diffusion electrodes compared to PGM electrodes. Furthermore, Ni-based catalysts are often easily submerged by the electrolyte in the thicker catalyst layer, which significantly reduces the catalytic performance and operating current density of hydrogen batteries. Therefore, developing Ni-based catalyst electrodes with lower costs and better catalytic performance is particularly important. Summary of the Invention
[0004] To address the aforementioned technical problems, this disclosure provides a hydrogen electrode, its preparation method, and its application in nickel-hydrogen batteries, aiming to at least partially solve the above-mentioned technical problems.
[0005] The technical solution provided in this disclosure is as follows:
[0006] As a first aspect of this disclosure, a hydrogen electrode is provided, comprising:
[0007] Gas diffusion layer electrode, and
[0008] A nickel-containing catalyst layer is formed on the gas diffusion layer electrode. The nickel-containing catalyst layer includes a nickel-based catalyst, a hydrophobic conductive fiber material, and a binder. The hydrophobic conductive fiber material is dispersed inside the nickel-containing catalyst layer to provide a channel for hydrogen transport. The length of the hydrophobic conductive fiber material is 1 to 100 μm. The gas diffusion layer electrode is a combination of a hydrophobic layer and a conductive layer, used for gas conduction and electrical conduction.
[0009] In one embodiment, the nickel-based catalyst comprises at least one of the following:
[0010] Alloys formed by Ni with any one of the elements Mo, W, Cr, Cu, and Nb, as well as nickel phosphide, nickel nitride, nickel boride, and nickel sulfide.
[0011] In one embodiment, the hydrophobic conductive fiber material is a conductive fiber material treated with polytetrafluoroethylene or polyvinylidene fluoride, and the conductive fiber material includes: carbon nanotubes, carbon fibers or metal fibers.
[0012] In one embodiment, the binder includes at least one of the following:
[0013] Polyvinylidene fluoride, styrene-butadiene rubber latex, carboxymethyl cellulose, polyacrylic acid, polyacrylonitrile, polyacrylate;
[0014] The gas diffusion layer electrode includes a carbon-based gas diffusion layer electrode.
[0015] In one embodiment, the nickel-based catalyst in the nickel-containing catalyst layer has a mass percentage content of 60-99.8%, a mass percentage content of 0.1-20%, and a mass percentage content of 0.1-20%, totaling 100%.
[0016] In one embodiment, the hydrogen electrode is suitable for neutral or alkaline environments.
[0017] As a second aspect of this disclosure, a method for preparing a hydrogen electrode is provided, comprising:
[0018] A slurry containing a nickel-based catalyst, hydrophobic conductive fiber material, and binder is coated onto a gas diffusion layer electrode and then dried to obtain a hydrogen electrode.
[0019] Among them, the hydrophobic conductive fiber material is obtained by immersing the conductive fiber material in a polytetrafluoroethylene or polyvinylidene fluoride solution, stirring, drying, and then annealing it under an inert atmosphere.
[0020] In one embodiment, the concentration of the polytetrafluoroethylene or polyvinylidene fluoride solution is 0.1-20 wt%.
[0021] In one embodiment, the drying temperature is 30-90°C and the drying time is 1-1000 min;
[0022] The annealing temperature is 200-400℃, and the annealing time is 10-120min.
[0023] As a third aspect of this disclosure, a nickel-metal hydride battery is provided, comprising:
[0024] The aforementioned hydrogen electrode;
[0025] Nickel hydroxide positive electrode;
[0026] Membrane materials; and
[0027] Electrolyte.
[0028] In the embodiments of this disclosure, a low-cost nickel-based catalyst, hydrophobic conductive fiber material, and binder are mixed and coated onto the surface of a gas diffusion electrode to form a nickel-containing catalyst layer. The hydrophobic conductive fiber material is dispersed within the nickel-containing catalyst layer, utilizing its porous structure to form a solid-liquid-gas three-phase interface. This interface facilitates the transfer of hydrogen generated during the electrochemical reaction, reducing competition between hydrogen and water for active sites in the nickel-containing catalyst layer and enhancing the degree of the HER reaction; or it can transport hydrogen to the surface of the nickel-containing catalyst layer, enhancing the degree of the HOR reaction. The gas diffusion layer electrode surface is hydrophobic and conductive, reducing water adsorption on its surface and improving the conductivity and catalytic activity of the hydrogen electrode, thus acting as a gas and conductor. The hydrogen electrode provided by this disclosure improves the conductivity and catalytic activity of traditional nickel-based catalysts and alleviates the aggregation of nickel-based catalysts, thereby further improving the electrochemical performance of the hydrogen electrode. Attached Figure Description
[0029] Figure 1A This is a schematic diagram illustrating the working principle of a traditional hydrogen electrode and a traditional nickel-based catalyst.
[0030] Figure 1B This is a schematic diagram illustrating the working principle of a conventional nickel-based catalyst for the hydrogen electrode in the embodiments of this disclosure;
[0031] Figure 2 The polarization curves and stability diagrams of the nickel-metal hydride battery electrodes in Embodiment 1 of this disclosure are shown.
[0032] Figure 3 This is a comparison chart of the performance output of the battery and the platinum electrode battery in Embodiment 1 of this disclosure;
[0033] Figure 4 This is a rate performance diagram of the nickel-metal hydride battery in Embodiment 2 of this disclosure;
[0034] Figure 5This is a cycle stability diagram of the nickel-metal hydride battery in Embodiment 3 of this disclosure. Detailed Implementation
[0035] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.
[0036] Although nickel-based catalysts exhibit good HER / HOR bifunctional reversible catalytic activity when used as electrodes, they suffer from lower activity compared to noble metal catalysts. Existing nickel-based catalysts, in an effort to achieve the same catalytic activity as Pt catalysts, often result in excessively thick catalyst layers. Consequently, the nickel-based catalyst is easily submerged in the electrolyte within these thick layers, affecting the overall performance of the catalyst layer. To address this, this disclosure provides a hydrogen electrode, its preparation method, and a nickel-hydrogen battery. By cleverly introducing hydrophobic conductive fiber materials into the nickel-containing catalyst layer, a conductive-hydrophobic network is formed, thereby improving the catalytic activity of the nickel-containing catalyst layer.
[0037] Specifically, the hydrogen electrode provided in this disclosure includes:
[0038] Gas diffusion layer electrode, and
[0039] A nickel-containing catalyst layer is formed on the gas diffusion layer electrode. The nickel-containing catalyst layer includes a nickel-based catalyst, a hydrophobic conductive fiber material, and a binder. The hydrophobic conductive fiber material is dispersed inside the nickel-containing catalyst layer to provide a channel for hydrogen transport. The length of the hydrophobic conductive fiber material is 1 to 100 μm. The gas diffusion layer electrode is a combination of a hydrophobic layer and a conductive layer, which is used for gas conduction and electrical conduction.
[0040] In the embodiments of this disclosure, a low-cost nickel-based catalyst is mixed with a hydrophobic conductive fiber material and a binder, and then coated onto the surface of a gas diffusion electrode to form a nickel-containing catalyst layer. The hydrophobic conductive fiber material is dispersed within the nickel-containing catalyst layer, utilizing its porous structure to form a solid-liquid-gas three-phase interface. This effectively transfers hydrogen generated during the electrochemical reaction, reducing competition between hydrogen and water for active sites in the nickel-containing catalyst layer and increasing the degree of the HER reaction; or it transports hydrogen to the surface of the nickel-containing catalyst layer, increasing the degree of the HOR reaction. Compared with conventional nickel-based catalysts, the hydrogen electrode provided by this disclosure improves the electrode's conductivity and alleviates the aggregation of nickel-based catalysts, thereby further improving the electrochemical performance of the hydrogen electrode. Simultaneously, the hydrogen electrode provided by this disclosure can achieve the same or even higher electrochemical activity as commercial Pt catalysts at the same cost, and is expected to replace traditional Pt catalysts.
[0041] According to embodiments of this disclosure, the nickel-based catalyst comprises at least one of the following:
[0042] Alloys formed by Ni with any one of the elements selected from Mo, W, Cr, Cu, and Nb, as well as nickel phosphide, nickel nitride, nickel boride, and nickel sulfide. The selected elements such as Mo, W, Cr, Cu, and Nb, when combined with Ni, can all exhibit good HER / HOR performance, meeting the requirements of hydrogen electrodes.
[0043] According to embodiments of this disclosure, the hydrophobic conductive fiber material is a conductive fiber material treated with polytetrafluoroethylene or polyvinylidene fluoride. The conductive fiber material includes carbon nanotubes, carbon fibers, or metal fibers. The carbon nanotubes can be multi-walled carbon nanotubes (MWCNTs). Other conductive fiber materials with continuous through-hole structures and pore lengths of 1 to 100 μm can also be used, which will not be described in detail here.
[0044] According to embodiments of this disclosure, the adhesive includes at least one of the following:
[0045] Polyvinylidene fluoride (PVDF), styrene-butadiene rubber (SBR) emulsion, carboxymethyl cellulose (CMC), polyacrylic acid (PAA), polyacrylonitrile (PAN), polyacrylate;
[0046] Gas diffusion layer electrodes (GDLs) include carbon-based gas diffusion layer electrodes. Other commercial gas diffusion layer electrodes with electrical and gas-conducting functions can also be used, but will not be described in detail here.
[0047] According to embodiments of this disclosure, the nickel-based catalyst in the nickel-containing catalyst layer has a mass percentage content of 60-99.8%, the hydrophobic conductive fiber material has a mass percentage content of 0.1-20%, preferably 10%-20%, and the binder has a mass percentage content of 0.1-20%, preferably 5%-15%, totaling 100%.
[0048] According to embodiments of this disclosure, the hydrogen electrode provided is suitable for neutral or alkaline environments, preferably alkaline environments.
[0049] Figure 1A This is a schematic diagram illustrating the working principle of a traditional hydrogen electrode and a traditional nickel-based catalyst. Figure 1B This is a schematic diagram illustrating the working principle of the hydrogen electrode and nickel-based catalyst in the embodiments of this disclosure.
[0050] like Figure 1AAs shown, the mass activity of non-precious metal catalysts is lower than that of commercial Pt electrodes. Therefore, the loading of low-cost non-precious metal catalysts needs to be tens of times higher than that of Pt catalysts to achieve performance comparable to Pt. This will significantly affect hydrogen transport within the catalyst layer of low-cost hydrogen electrodes. For example, in the HER reaction (hydrogen generation from water) of traditional nickel-based catalysts (NiMo), hydrogen is continuously generated on the surface of the nickel-based catalyst. Hydrogen bubbles accumulate in the thick catalyst layer and cannot diffuse out, hindering the penetration of liquid electrolyte and clogging the active sites of the catalyst, thus reducing the HER reaction performance of nickel-hydrogen batteries. Similarly, since HOR is a process that continuously consumes hydrogen, during the HOR reaction (water generation from hydrogen), the nickel catalyst inside the nickel-based catalyst layer is submerged by the liquid electrolyte. This results in poor hydrogen supply and slow diffusion on most of the catalyst surface, preventing effective water formation and thus reducing HOR efficiency.
[0051] In contrast, in this embodiment, hydrophobic conductive fiber material is uniformly dispersed within the nickel-containing catalyst layer to form a stable conductive-hydrophobic network, reducing water adhesion to the surface of the nickel-containing catalyst layer. Simultaneously, the hydrophobic conductive fiber material constructs a continuous gas transport channel within the nickel-containing catalyst layer, contributing to improved overall permeability of the hydrogen electrode. During the HER reaction, the porous structure of the hydrophobic conductive fiber material allows hydrogen generated from water electrolysis to be transported through its pores, transferring hydrogen generated on the surface of the nickel-containing catalyst layer to the gas diffusion layer electrode for release. This reduces competition between hydrogen and water for active sites on the nickel-containing catalyst layer surface, effectively ensuring the HER reaction proceeds. Similarly, during the HOR reaction, the pores of the hydrophobic conductive fiber material allow hydrogen generated in the HER reaction to be transported back to the surface of the nickel-containing catalyst layer for replenishment, catalyzing the production of water.
[0052] According to embodiments of this disclosure, a method for preparing a hydrogen electrode is also provided, comprising:
[0053] A slurry containing a nickel-based catalyst, hydrophobic conductive fiber material, and binder is coated onto a gas diffusion layer electrode and then dried to obtain a hydrogen electrode.
[0054] Among them, the hydrophobic conductive fiber material is obtained by immersing the conductive fiber material in a polytetrafluoroethylene or polyvinylidene fluoride solution, stirring, drying, and then annealing it under an inert atmosphere.
[0055] More specifically, the preparation method of the hydrophobic conductive fiber material includes: immersing a commercially available conductive fiber material in an aqueous solution of polytetrafluoroethylene (PTFE) or in an N-methylpyrrolidone (NMP) solvent of polyvinylidene fluoride (PVDF) while stirring. After collection and drying, the material is annealed in argon gas to obtain the hydrophobic conductive fiber material. The drying temperature of the hydrogen electrode is 30-90℃, optionally 30℃, 50℃, 90℃, etc., and the drying time is 1-1000 min, optionally 1 min, 10 min, 100 min, 500 min, 1000 min, etc. For example, commercially available carbon nanotubes are immersed in an aqueous solution of polytetrafluoroethylene (PTFE) or in an N-methylpyrrolidone (NMP) solvent of polyvinylidene fluoride (PVDF) while stirring. After collection and drying, the material is annealed in argon gas to obtain the hydrophobic carbon nanotubes.
[0056] The annealing temperature for hydrophobic conductive fiber materials is 200-400℃, such as 200℃, 300℃, 400℃, etc., and the annealing time is 10-120min, such as 10min, 50min, 100min, 120min, etc. By controlling the annealing time and temperature, excess polytetrafluoroethylene solution and polyvinylidene fluoride solution can be removed from the surface of the hydrophobic conductive fiber material, reducing the clogging of the pores of the hydrophobic conductive fiber material.
[0057] In the embodiments of this disclosure, a hydrogen electrode can be obtained by spin-coating a slurry made of a low-cost nickel-based catalyst, a binder, and a hydrophobic conductive fiber material onto the surface of a gas diffusion electrode using a simple spin-coating process. This process is low-cost, simple, and easy to scale up.
[0058] According to embodiments of this disclosure, the concentration of the polytetrafluoroethylene or polyvinylidene fluoride solution is 0.1-20 wt%, which can be selected as 0.1 wt%, 10 wt%, 20 wt%, etc. The hydrogen electrode obtained within this concentration range has good conductivity and hydrophobicity.
[0059] According to embodiments of this disclosure, the length of the hydrophobic conductive fiber material is 1 to 100 μm, wherein the hydrophobic conductive fiber material is a continuous channel that can be used as a gas transmission channel.
[0060] According to embodiments of this disclosure, this disclosure also provides a nickel-metal hydride battery, comprising:
[0061] The hydrogen electrode, nickel hydroxide positive electrode, membrane material, and electrolyte in the above embodiments.
[0062] The membrane material can be polyethylene, polypropylene, glass fiber, etc.; the electrolyte can be sodium hydroxide solution, potassium hydroxide solution, etc.
[0063] According to embodiments of this disclosure, the hydrogen battery further includes: a housing to form a sealed container, in which hydrogen is filled and sealed, wherein the housing may be made of stainless steel.
[0064] In the embodiments of this disclosure, the nickel-metal hydride battery assembled using the hydrogen electrode provided in the embodiments of this disclosure can maintain high energy density and rate performance and significantly reduce the battery stack cost.
[0065] The present disclosure will now be described in detail with reference to specific embodiments and accompanying drawings. However, it should be noted that the embodiments provided in this disclosure are for illustrative purposes only and do not limit the scope of protection of this disclosure.
[0066] Example
[0067] Example 1
[0068] Synthesis of Ni4Mo catalyst: First, 3.2 mmol of nickel nitrate and 0.114 mmol of ammonium molybdate were dissolved in 8 mL of deionized water, 3.2 mL of concentrated ammonia, and 72 mL of ethylene glycol, and the mixture was stirred continuously. The reaction solution was heated at 150 °C for 30 minutes to form a light green precipitate, which was collected by centrifugation as a precursor. Then, the Ni4Mo-OH precursor was annealed at 420 °C for 1 h in 5% H2 / Ar to form Ni4Mo. o Nanoparticles. The final product is then stored in a glove box to prevent oxidation. Catalysts with different NiMo ratios can be obtained by changing the molar ratio of the metals in nickel nitrate and ammonium molybdate.
[0069] Synthesis process of hydrophobic multi-walled carbon nanotubes (MWCNTs): First, 50 mg of commercial MWCNTs (Macklin) with a length of 10-20 μm were soaked in 1 mL of 0.2 wt% PTFE aqueous solution, stirred continuously for 1 hour, collected, dried, and annealed in Ar at 300 °C for 30 min.
[0070] Preparation of hydrogen battery electrode: A slurry was prepared by mixing 85 mg Ni4Mo, 5 mg hydrophobic MWCNTs, and 10 mg PVDF in 1 mL NMP solution, and then coated onto the gas diffusion layer electrode. The catalyst loading was 6 mg cm⁻¹. -2 In comparison, this disclosure also prepared a 0.3 mg cm -2 The cost of the Pt / C hydrogen catalytic electrode is an order of magnitude higher than that of the Ni4Mo electrode.
[0071] Preparation of nickel-metal hydride (NiMH) batteries: The outer casing of the NiMH battery is a sealed container made of stainless steel, which serves to fill and seal high-pressure hydrogen gas. Inside the battery, nickel hydroxide is used as the positive electrode, and the prepared hydrogen electrode is used as the negative electrode. The positive and negative electrodes are separated by a separator material, and the electrolyte is 8 mol / L potassium hydroxide.
[0072] The assembled nickel-metal hydride battery underwent electrochemical performance testing of its electrodes. Electrode polarization was measured at room temperature and 3 mA / cm². 2 The test was conducted at a current density of ~50mV, and the specific test results are as follows: Figure 2 As shown.
[0073] Figure 2 The polarization curves and stability diagrams of the nickel-metal hydride battery electrodes in Embodiment 1 of this disclosure are shown.
[0074] like Figure 2 As shown, the polarization remained stable after 250 hours of testing.
[0075] Furthermore, this disclosure also tests the electrochemical performance of the above-mentioned battery at room temperature, and the specific test results are as follows: Figure 3 As shown.
[0076] Figure 3 This is a comparison chart of the performance output of the battery and the platinum electrode battery in Embodiment 1 of this disclosure.
[0077] like Figure 3 As shown, the battery stack cost in Embodiment 1 of this disclosure is reduced by more than three times compared to the traditional platinum electrode battery, but the energy efficiency of the nickel-metal hydride battery in Embodiment 1 is significantly higher than that of the platinum electrode battery.
[0078] Example 2
[0079] Preparation of hydrogen battery electrode: A slurry was prepared by mixing 80 mg Ni5Mo, 10 mg hydrophobic MWCNTs, and 10 mg PVDF in 1 mL NMP solution, and then coated onto the gas diffusion layer electrode. The catalyst loading was 6 mg cm⁻¹. -2 The preparation method of the Ni5Mo catalyst is the same as that in Example 1, the only difference being the ratio of Ni to Mo.
[0080] Preparation of nickel-metal hydride batteries: The outer shell of the nickel-metal hydride battery is a sealed container made of stainless steel, which serves to fill and seal high-pressure hydrogen gas. The interior consists of a nickel hydroxide positive electrode, a prepared hydrogen negative electrode, and a separator material. The electrolyte is 8 mol / L potassium hydroxide.
[0081] The assembled nickel-metal hydride battery underwent electrochemical performance testing, including testing the discharge capacity and energy efficiency at different current densities at room temperature. Specific test results are as follows: Figure 4 As shown.
[0082] Figure 4 This is a rate performance diagram of the nickel-metal hydride battery in Embodiment 2 of this disclosure.
[0083] like Figure 4 As shown, the discharge capacity of the nickel-metal hydride battery provided in this disclosure can reach 15 mAh / cm³. 2 , at 2mA cm -2 ~6mA cm -2 At current density, the battery energy efficiency can still reach over 80%.
[0084] Example 3
[0085] Synthesis of Ni / MoO2 catalyst: First, 1 mmol of nickel nitrate was dissolved in 30 mL of deionized water. Then, 5 mmol of urea, 3 mmol of ammonium fluoride, and 1 mmol of sodium molybdate were added continuously with stirring. The mixture was then transferred to a 50 mL Teflon autoclave and heated at 150 °C for 10 h. The resulting NiMoO4 precipitate was collected by centrifugation, washed several times with deionized water / ethanol alternately, and dried overnight in a vacuum furnace at 60 °C. It was then heated in a tube furnace at 400 °C for 2 h in a 10% Ar / H2 atmosphere. The final product was stored in a glove box to prevent any possible oxidation.
[0086] Preparation of hydrogen battery electrode: A slurry was prepared by mixing 80 mg Ni / MoO2, 10 mg hydrophobic MWCNTs, and 10 mg PVDF in 1 mL NMP solution, and then coated onto the gas diffusion layer electrode. The Ni / MoO2 catalyst loading was 10 mg cm⁻¹. -2 .
[0087] Preparation of nickel-metal hydride batteries: The outer shell of the nickel-metal hydride battery is a sealed container made of stainless steel, which serves to fill and seal high-pressure hydrogen gas. The inside of the battery consists of a nickel hydroxide positive electrode, a hydrogen negative electrode prepared by the battery, and a separator material. The electrolyte is 8 mol / L potassium hydroxide.
[0088] The assembled nickel-metal hydride battery underwent electrochemical performance testing, including cycle stability and coulombic efficiency tests at room temperature. Specific test results are as follows: Figure 5 As shown.
[0089] Figure 5 This is a cycle stability diagram of the nickel-metal hydride battery in Embodiment 3 of this disclosure.
[0090] like Figure 5 As shown, the discharge capacity of the nickel-metal hydride battery provided in this disclosure can reach 15 mAh / cm³. 2 At 100 DoD%, at 4 mA / cm2 The current density remains stable for 200 cycles without capacity decay.
[0091] The specific embodiments described above further illustrate the purpose, technical solutions, and beneficial effects of this disclosure. It should be understood that the above descriptions are merely specific embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.
Claims
1. A hydrogen electrode, comprising: Gas diffusion layer electrode, and A nickel-containing catalyst layer is formed on the gas diffusion layer electrode. The nickel-containing catalyst layer comprises a nickel-based catalyst, a hydrophobic conductive fiber material, and a binder. The hydrophobic conductive fiber material is dispersed inside the nickel-containing catalyst layer to provide a channel for hydrogen transport. The length of the hydrophobic conductive fiber material is 1 to 100 μm. The gas diffusion layer electrode is a combination of a hydrophobic layer and a conductive layer for guiding gas and conducting electricity.
2. The hydrogen electrode of claim 1, wherein, The nickel-based catalyst includes at least one of the following: Alloys formed by Ni with any one of the elements Mo, W, Cr, Cu, and Nb, as well as nickel phosphide, nickel nitride, nickel boride, and nickel sulfide.
3. The hydrogen electrode of claim 1, wherein, The hydrophobic conductive fiber material is a conductive fiber material treated with polytetrafluoroethylene or polyvinylidene fluoride, and the conductive fiber material includes: carbon nanotubes, carbon fibers or metal fibers.
4. The hydrogen electrode of claim 1, wherein, The adhesive includes at least one of the following: Polyvinylidene fluoride, styrene-butadiene rubber latex, carboxymethyl cellulose, polyacrylic acid, polyacrylonitrile, polyacrylate; The gas diffusion layer electrode includes a carbon-based gas diffusion layer electrode.
5. The hydrogen electrode according to claim 1, wherein, The nickel-based catalyst in the nickel-containing catalyst layer has a mass percentage content of 60-99.8%, the hydrophobic conductive fiber material has a mass percentage content of 0.1-20%, and the binder has a mass percentage content of 0.1-20%, totaling 100%.
6. The hydrogen electrode according to claim 1, wherein, The hydrogen electrode is suitable for neutral or alkaline environments.
7. A method for preparing a hydrogen electrode as described in any one of claims 1 to 6, comprising: A slurry containing a nickel-based catalyst, hydrophobic conductive fiber material, and binder is coated onto a gas diffusion layer electrode and then dried to obtain a hydrogen electrode. The hydrophobic conductive fiber material is obtained by immersing the conductive fiber material in a polytetrafluoroethylene or polyvinylidene fluoride solution, stirring, drying, and then annealing it under an inert atmosphere.
8. The method according to claim 7, wherein, The concentration of the polytetrafluoroethylene or polyvinylidene fluoride solution is 0.1-20 wt%.
9. The method according to claim 7, wherein, The drying temperature is 30-90℃, and the drying time is 1-1000 min; The annealing temperature is 200-400℃, and the annealing time is 10-120min.
10. A nickel-metal hydride battery, comprising: Hydrogen electrode as described in any one of claims 1 to 6; Nickel hydroxide positive electrode; Diaphragm material; and Electrolyte.