Preparation of high-capacity hydrogen storage alloy

Abstract

The invention discloses preparation of a high-capacity hydrogen storage alloy, and relates to the technical field of alloys. The hydrogen absorption alloy is composed of nickel, zirconium and lithium, and the lithium reduces the electronegativity and enhances the hydrogen storage capacity; zirconium improves phase morphology, improves crystal structure stability, reduces lattice distortion and improves cycling stability. Lithium and zirconium partially replace nickel, so that the mechanical property is improved, high hydrogen storage density is achieved, and the hydrogen absorption capacity is improved. And by adjusting the proportion, the hydrogen storage capacity and the cycle life are improved. And micron-sized metal zirconium powder is added into pure nickel melt, so that the mechanical property of Ni-Zr alloy powder is improved, the influence of gas atomization quenching is reduced, and the performance of the hydrogen absorption alloy is improved. The lithium powder is low in melting point and easy to volatilize, in order to maintain the proportion of the lithium element in the alloy, the lithium powder and the Ni-Zr alloy powder are treated through mechanical alloying, it is ensured that lithium is evenly dispersed, loss is reduced, alloy components are stabilized, all elements are evenly distributed, and the hydrogen absorption capacity and strength are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of alloys, and specifically to the preparation of a high-capacity hydrogen storage alloy. Background Art

[0002] In nature, there are some special metals that have a very powerful ability to capture and combine hydrogen. Under specific temperature and pressure conditions, these metals can "absorb" a large amount of hydrogen molecules and react with them chemically to form metal hydrides. During this process, a certain amount of heat is released. Subsequently, if we heat-treat these metal hydrides, they will undergo a decomposition reaction and release the previously stored hydrogen. These metals that can "absorb" hydrogen are usually called hydrogen-absorbing alloys.

[0003] As an important energy storage device, the electrochemical performance of nickel-metal hydride batteries depends to a large extent on the performance of the negative electrode material, that is, the hydrogen-absorbing alloy. Currently, the commonly used hydrogen-absorbing alloy is AB 5 type hydrogen storage alloy. Although the AB 5 type hydrogen storage alloy performs well in some aspects, its capacity is limited, and there is a large charge transfer impedance on the electrode surface, which will significantly affect the charge and discharge efficiency of the battery. Moreover, it is difficult to simultaneously achieve the dual advantages of high capacity and long-term cycle life. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing a high-capacity hydrogen storage alloy to solve the problems existing in the prior art.

[0005] To solve the above technical problems, the present invention provides the following technical solution: A method for preparing a high-capacity hydrogen storage alloy, comprising the following preparation steps: (1) Heat the pure nickel powder to a completely molten state, turn on the electromagnetic stirring device provided at the bottom of the melting furnace, add the preheated metal zirconium powder, ultrasonically stir for 15 - 30 min, and then add it to the gas atomization chamber for atomization to obtain Ni-Zr alloy powder; (2) Perform high-energy ball milling on the Ni-Zr alloy powder obtained in step (1) and pure lithium powder. The powder is loaded into a mold for pressing and forming. Under argon protection, heat-treat at 180 - 350 °C for 2 - 5 h, and then raise the temperature to 400 - 600 °C and heat-treat for 30 min to obtain a circular high-capacity hydrogen storage alloy electrode sheet with a diameter of 15 mm.

[0006] Further, the dosage of the pure nickel powder is 50 - 65 parts by weight, the dosage of the metal zirconium powder is 7 - 15 parts by weight, and the dosage of the pure lithium powder is 20 - 35 parts by weight.

[0007] Further, the particle size of the pure nickel powder is 1 - 5 mm.

[0008] Further, in step (1), the preheating temperature of the zirconium powder is 600 - 650°C, and the preheating time is 10 - 30 min.

[0009] Further, the diameter of the zirconium powder described in step (1) is 10 - 20 μm.

[0010] Further, in step (1), the atomization medium is argon with a purity of more than 99.9%, the gas atomization pressure is 0.5 MPa - 10 MPa, and the flow rate is controlled at 4 L / min - 20 L / min.

[0011] Further, in step (1), the frequency of the electromagnetic stirring device at the bottom of the melting furnace is 2000 - 5000 Hz.

[0012] Further, the particle size of the pure lithium powder described in step (2) is 20 - 50 μm.

[0013] Further, in step (2), the ball - to - material ratio for the ball - milling treatment is 15:1, the ball - milling is carried out for 40 h, and the rotation speed of the ball mill is selected to be 200 r / min.

[0014] Further, in step (2), the pressing pressure is 8 - 15 MPa, and the pressure - holding time is 0 - 30 s.

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: (1) In the present invention, the hydrogen - absorbing alloy involved is composed of three elements: nickel (Ni), zirconium (Zr), and lithium (Li). As an element with a low electronegativity, lithium (Li) can effectively reduce the average electronegativity inside the alloy when added to the alloy. This effect of reducing electronegativity can further increase the hydrogen storage capacity of the alloy. In addition, by adding a small amount of zirconium (Zr) element to the alloy, the phase morphology of the alloy can be changed, thereby improving the stability of the crystal structure. This improvement in stability helps to reduce the lattice distortion phenomenon caused by the crystal structure transformation during the hydrogen absorption and desorption process of the alloy. Therefore, the addition of a trace amount of zirconium element has a significant promoting effect on enhancing the cycle stability of the alloy. At the same time, the strategy of partially replacing nickel (Ni) with lithium (Li) and zirconium (Zr) not only improves the mechanical properties of the alloy but also endows the alloy with a high hydrogen storage density, which is very beneficial for improving the hydrogen absorption capacity of the alloy. The present invention also adjusts the proportional relationship between alloy elements to achieve the precise substitution and combination of lithium (Li) and zirconium (Zr) atoms with nickel (Ni) atoms, thereby significantly enhancing the hydrogen storage capacity and cycle life of the hydrogen - storage alloy.

[0016] (2) In the present invention, micron-sized metal Zr powder is added to the pure nickel melt. Since the melting point of the metal Zr powder is higher than that of the metal nickel powder, the metal Zr powder is in an incompletely molten state in the pure nickel melt, thereby forming nucleation particles, improving the mechanical properties of the Ni-Zr alloy powder, and also reducing the adverse effects of rapid cooling in subsequent gas atomization, which is beneficial to improving the performance of the hydrogen storage alloy.

[0017] (3) Since the melting point of Li powder is relatively low and it is easy to volatilize during the melting process, in order to ensure that the Li element in the obtained hydrogen storage alloy is within the predetermined proportion range, the present invention performs mechanical alloying treatment on the Li powder and the Ni-Zr alloy powder to achieve uniform dispersion of the Li powder, reduce the loss of the Li element, ensure the stability of the alloy composition and the uniform distribution of each element, and at the same time enable the preliminary combination of Li atoms and the Ni-Zr alloy powder. After pressing and forming, heat treatment is carried out to achieve the further combination of Li atoms with Ni and Zr atoms, and at the same time promote the homogenization of Ni-Zr, thereby improving the hydrogen absorption capacity and strength. Specific Embodiments

[0018] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0019] Example 1; (1) 50 parts by weight of pure nickel powder is heated to a completely molten state in a vacuum induction melting furnace with a vacuum degree of 2×10 -2 Pa and a temperature of 1453 °C. The electromagnetic stirring device provided at the bottom of the melting furnace is turned on, and the frequency of the electromagnetic stirring device at the bottom of the melting furnace is maintained at 2000 Hz. 7 parts by weight of preheated metal zirconium powder is added. After ultrasonic stirring for 15 min, it is added to the gas atomization chamber for atomization. The atomization medium is argon with a purity of more than 99.9%, the gas atomization pressure is 0.5 MPa, and the flow rate is controlled at 4 L / min to obtain Ni-Zr alloy powder; the preheating temperature of the metal zirconium powder is 600 °C, the preheating time is 10 min, and the diameter of the metal zirconium powder is 10 μm; (2) The Ni-Zr alloy powder obtained in step (1) and 20 parts by weight of pure lithium powder with a particle size of 20 μm are subjected to high-energy ball milling treatment. The ball-to-powder ratio is 15:1, and the ball milling is carried out for 40 h. The rotation speed of the ball mill is selected as 200 r / min. The powder is loaded into a mold for pressing and forming treatment. The pressing pressure is 8 MPa, and the pressure holding time is 10 s. Under argon protection, heat treatment is carried out at 180 °C for 5 h, and then the temperature is raised to 400 °C for heat treatment for 30 min to obtain a circular high-capacity hydrogen storage alloy electrode sheet with a diameter of 15 mm.

[0020] Example 2; (1) 52.5 parts by weight of pure nickel powder was heated to a completely molten state in a vacuum induction melting furnace with a vacuum degree of 2×10 -2 Pa and a temperature of 1453 °C. The electromagnetic stirring device provided at the bottom of the melting furnace was turned on, and the frequency of the electromagnetic stirring device at the bottom of the melting furnace was maintained at 2000 Hz. 8.3 parts by weight of preheated metal zirconium powder was added. After ultrasonic stirring for 15 min, it was added to the gas atomization chamber for atomization. The atomization medium was argon with a purity of more than 99.9%, the gas atomization pressure was 2 MPa, and the flow rate was controlled at 6.7 L / min to obtain Ni-Zr alloy powder; the preheating temperature of the metal zirconium powder was 600 °C, the preheating time was 10 min, and the diameter of the metal zirconium powder was 10 μm; (2) The Ni-Zr alloy powder obtained in step (1) and 22.5 parts by weight of pure lithium powder with a particle size of 20 μm were subjected to high-energy ball milling. The ball-to-powder ratio was 15:1, and ball milling was carried out for 40 h. The rotation speed of the ball mill was selected to be 200 r / min. The powder was loaded into a mold for pressing and forming. The pressing pressure was 8 MPa, and the pressure holding time was 10 s. Under argon protection, it was heat-treated at 208 °C for 5 h and then heated to 430 °C and heat-treated for 30 min to obtain a circular high-capacity hydrogen storage alloy electrode sheet with a diameter of 15 mm.

[0021] Example 3; (1) 55 parts by weight of pure nickel powder was heated to a completely molten state in a vacuum induction melting furnace with a vacuum degree of 2×10 -2 Pa and a temperature of 1453 °C. The electromagnetic stirring device provided at the bottom of the melting furnace was turned on, and the frequency of the electromagnetic stirring device at the bottom of the melting furnace was maintained at 3500 Hz. 9.6 parts by weight of preheated metal zirconium powder was added. After ultrasonic stirring for 22 min, it was added to the gas atomization chamber for atomization. The atomization medium was argon with a purity of more than 99.9%, the gas atomization pressure was 3.6 MPa, and the flow rate was controlled at 9 L / min to obtain Ni-Zr alloy powder; the preheating temperature of the metal zirconium powder was 625 °C, the preheating time was 20 min, and the diameter of the metal zirconium powder was 15 μm; (2) The Ni-Zr alloy powder obtained in step (1) and 25 parts by weight of pure lithium powder with a particle size of 35 μm were subjected to high-energy ball milling. The ball-to-powder ratio was 15:1, and ball milling was carried out for 40 h. The rotation speed of the ball mill was selected to be 200 r / min. The powder was loaded into a mold for pressing and forming. The pressing pressure was 10 MPa, and the pressure holding time was 20 s. Under argon protection, it was heat-treated at 236 °C for 3 h and then heated to 466 °C and heat-treated for 30 min to obtain a circular high-capacity hydrogen storage alloy electrode sheet with a diameter of 15 mm.

[0022] Example 4; (1) 57.5 parts by weight of pure nickel powder was in a vacuum of 3×10 -2In a vacuum induction melting furnace at a pressure of Pa and a temperature of 1453 °C, it is heated to a completely molten state. The electromagnetic stirring device set at the bottom of the melting furnace is turned on, and the frequency of the electromagnetic stirring device at the bottom of the melting furnace is maintained at 2500 Hz. 7 parts by weight of preheated zirconium metal powder is added. After ultrasonic stirring for 22 min, it is added to the gas atomization chamber for atomization. The atomization medium is argon with a purity of more than 99.9%. The gas atomization pressure is 5.2 MPa, and the flow rate is controlled at 12 L / min to obtain Ni-Zr alloy powder; the preheating temperature of the zirconium metal powder is 625 °C, the preheating time is 20 min, and the diameter of the zirconium metal powder is 15 μm; (2) The Ni-Zr alloy powder obtained in step (1) and 22 parts by weight of pure lithium powder with a particle size of 35 μm are subjected to high-energy ball milling. The ball-to-powder ratio is 15:1, and ball milling is carried out for 40 h. The rotation speed of the ball mill is selected as 200 r / min. The powder is loaded into a mold for pressing treatment. The pressing pressure is 10 MPa, and the pressure holding time is 20 s. Under argon protection, it is heat-treated at 265 °C for 3 h, and then heated to 500 °C and heat-treated for 30 min to obtain a circular high-capacity hydrogen storage alloy electrode sheet with a diameter of 15 mm.

[0023] Example 5; (1) 60 parts by weight of pure nickel powder at a vacuum degree of 3×10 -2 In a vacuum induction melting furnace at a pressure of Pa and a temperature of 1453 °C, it is heated to a completely molten state. The electromagnetic stirring device set at the bottom of the melting furnace is turned on, and the frequency of the electromagnetic stirring device at the bottom of the melting furnace is maintained at 5000 Hz. 15 parts by weight of preheated zirconium metal powder is added. After ultrasonic stirring for 30 min, it is added to the gas atomization chamber for atomization. The atomization medium is argon with a purity of more than 99.9%. The gas atomization pressure is 6.8 MPa, and the flow rate is controlled at 14 L / min to obtain Ni-Zr alloy powder; the preheating temperature of the zirconium metal powder is 650 °C, the preheating time is 10 min, and the diameter of the zirconium metal powder is 15 μm; (2) The Ni-Zr alloy powder obtained in step (1) and 35 parts by weight of pure lithium powder with a particle size of 35 μm are subjected to high-energy ball milling. The ball-to-powder ratio is 15:1, and ball milling is carried out for 40 h. The rotation speed of the ball mill is selected as 200 r / min. The powder is loaded into a mold for pressing treatment. The pressing pressure is 10 MPa, and the pressure holding time is 20 s. Under argon protection, it is heat-treated at 290 °C for 5 h, and then heated to 530 °C and heat-treated for 30 min to obtain a circular high-capacity hydrogen storage alloy electrode sheet with a diameter of 15 mm.

[0024] Example 6; (1) 62.5 parts by weight of pure nickel powder at a vacuum degree of 3×10 -2Heat 65 parts by weight of pure nickel powder to the completely molten state in a vacuum induction melting furnace with a vacuum of 3×10 Pa and a temperature of 1453 °C. Turn on the electromagnetic stirring device installed at the bottom of the melting furnace, keep the frequency of the electromagnetic stirring device at the bottom of the melting furnace at 5000 Hz, add 10 parts by weight of preheated zirconium metal powder, after ultrasonic stirring for 30 min, add it to the gas atomization chamber for atomization. The atomization medium is argon with a purity of more than 99.9%, the gas atomization pressure is 8.4 MPa, and the flow rate is controlled at 17 L / min to obtain Ni-Zr alloy powder; the preheating temperature of the zirconium metal powder is 650 °C, the preheating time is 30 min, and the diameter of the zirconium metal powder is 20 μm;

[0025] Example 7; (1) Heat 65 parts by weight of pure nickel powder to the completely molten state in a vacuum induction melting furnace with a vacuum of 3×10 -2 Pa and a temperature of 1453 °C. Turn on the electromagnetic stirring device installed at the bottom of the melting furnace, keep the frequency of the electromagnetic stirring device at the bottom of the melting furnace at 5000 Hz, add 7 parts by weight of preheated zirconium metal powder, after ultrasonic stirring for 30 min, add it to the gas atomization chamber for atomization. The atomization medium is argon with a purity of more than 99.9%, the gas atomization pressure is 10 MPa, and the flow rate is controlled at 20 L / min to obtain Ni-Zr alloy powder; the preheating temperature of the zirconium metal powder is 650 °C, the preheating time is 30 min, and the diameter of the zirconium metal powder is 20 μm; (2) Perform high-energy ball milling on the Ni-Zr alloy powder obtained in step (1) and 20 parts by weight of pure lithium powder with a particle size of 20 μm, with a ball-to-powder ratio of 15:1, ball mill for 40 h, select the rotation speed of the ball mill to be 200 r / min, load the powder into the mold for pressing treatment, with a pressing pressure of 15 MPa and a holding pressure time of 30 s. Under argon protection, heat treat at 350 °C for 5 h, then raise the temperature to 600 °C and heat treat for 30 min to obtain a circular high-capacity hydrogen storage alloy electrode sheet with a diameter of 15 mm.

[0026] Comparative Example 1; (1) 62.5 parts by weight of pure nickel powder in a vacuum of 3×10 -2It is heated to the completely molten state in a vacuum induction melting furnace at 1453 °C and a pressure of Pa. The electromagnetic stirring device set at the bottom of the melting furnace is turned on, and the frequency of the electromagnetic stirring device at the bottom of the melting furnace is maintained at 5000 Hz. 10 parts by weight of preheated zirconium metal powder and 32.5 parts by weight of pure lithium powder with a particle size of 50 μm are added. After ultrasonic stirring for 30 min, it is added to the gas atomization chamber for atomization. The atomization medium is argon with a purity of more than 99.9%, the gas atomization pressure is 8.4 MPa, and the flow rate is controlled at 17 L / min to obtain Ni-Zr-Li alloy powder; the preheating temperature of the zirconium metal powder is 650 °C, the preheating time is 30 min, and the diameter of the zirconium metal powder is 20 μm; (2) The powder is put into a mold for pressing treatment. The pressing pressure is 15 MPa, and the pressure holding time is 30 s. Under argon protection, it is heat-treated at 320 °C for 5 h, and then heated to 560 °C and heat-treated for 30 min to obtain a circular high-capacity hydrogen storage alloy electrode sheet with a diameter of 15 mm.

[0027] Comparative Example 2: 62.5 parts by weight of pure nickel powder and 32.5 parts by weight of pure lithium powder with a particle size of 50 μm are subjected to high-energy ball milling treatment. The ball-to-powder ratio is 15:1, and the ball milling is carried out for 40 h. The rotation speed of the ball mill is selected to be 200 r / min. The powder is put into a mold for pressing treatment. The pressing pressure is 15 MPa, and the pressure holding time is 30 s. Under argon protection, it is heat-treated at 320 °C for 5 h, and then heated to 560 °C and heat-treated for 30 min to obtain a circular high-capacity hydrogen storage alloy electrode sheet with a diameter of 15 mm.

[0028] Comparative Example 3; (1) 62.5 parts by weight of pure nickel powder is heated to the completely molten state in a vacuum induction melting furnace at a vacuum of 3×10 -2 Pa and a temperature of 1453 °C. The electromagnetic stirring device set at the bottom of the melting furnace is turned on, and the frequency of the electromagnetic stirring device at the bottom of the melting furnace is maintained at 5000 Hz. 10 parts by weight of preheated zirconium metal powder is added. After ultrasonic stirring for 30 min, it is added to the gas atomization chamber for atomization. The atomization medium is argon with a purity of more than 99.9%, the gas atomization pressure is 8.4 MPa, and the flow rate is controlled at 17 L / min to obtain Ni-Zr alloy powder; the preheating temperature of the zirconium metal powder is 650 °C, the preheating time is 30 min, and the diameter of the zirconium metal powder is 20 μm; (2) The powder is put into a mold for pressing treatment. The pressing pressure is 15 MPa, and the pressure holding time is 30 s. Under argon protection, it is heat-treated at 320 °C for 5 h, and then heated to 560 °C and heat-treated for 30 min to obtain a circular high-capacity hydrogen storage alloy electrode sheet with a diameter of 15 mm.

[0029] Comparative Example 4; (1) 62.5 parts by weight of pure nickel powder is at a vacuum of 3×10 -2Heat it up to the completely molten state in a vacuum induction melting furnace at 1453 °C under a pressure of Pa. Turn on the electromagnetic stirring device installed at the bottom of the melting furnace, and keep the frequency of the electromagnetic stirring device at the bottom of the melting furnace at 5000 Hz. Add 10 parts by weight of preheated zirconium metal powder. After ultrasonic stirring for 30 minutes, add it to the gas atomization chamber for atomization. The atomization medium is argon with a purity of more than 99.9%. The gas atomization pressure is 8.4 MPa, and the flow rate is controlled at 17 L / min to obtain Ni-Zr alloy powder; the preheating temperature of the zirconium metal powder is 650 °C, the preheating time is 30 minutes, and the diameter of the zirconium metal powder is 20 μm. (2) Perform high-energy ball milling on the Ni-Zr alloy powder obtained in step (1) and 32.5 parts by weight of pure lithium powder with a particle size of 50 μm. The ball-to-powder ratio is 15:1, and ball milling is carried out for 40 h. The rotation speed of the ball mill is selected to be 200 r / min. The powder is loaded into a mold for pressing treatment. The pressing pressure is 15 MPa, and the pressure holding time is 30 s to obtain a circular high-capacity hydrogen storage alloy electrode sheet with a diameter of 15 mm.

[0030] Performance testing The PCT test is carried out on a PCT tester produced by Suzuki Corporation of Japan. The test conditions are: charging and discharging hydrogen at 45 °C, and taking the hydrogen release pressure value when H / M = 3 as the PCT plateau pressure.

[0031] The electrochemical test method for the hydrogen storage alloy powder is as follows: Clamp the high-capacity hydrogen storage alloy electrode sheet with a nickel strip, place it in a 6 mol / L KOH electrolyte solution, use a Hg / HgO in the same solution as the reference electrode, and use two sintered nickel electrodes as the auxiliary electrodes to form a three-electrode system. On an American arbin electrochemical tester, under the condition of an ambient temperature of 20 ± 5 °C, charge-discharge tests are carried out.

[0032] The test method for the discharge capacity of the hydrogen storage alloy powder: Charge at a current of 60 mA / g for 7.5 h, rest for 30 minutes, then discharge at a current of 60 mA / g to -0.74 V vs. Hg / HgO, rest for 30 minutes, and then carry out the next cycle. Take the highest discharge capacity as the electrochemical capacity of the hydrogen storage alloy powder.

[0033] The test method for the cycle life of the hydrogen storage alloy powder: According to the above test method for measuring the maximum discharge capacity, after determining the maximum discharge capacity of the hydrogen storage alloy, charge at 300 mA / g for 75 min, pause for 10 min, then discharge at 300 mA / g to -65 V VS. Hg / HgO, and cycle the above process. When the charge-discharge parameters cycle to the point where the discharge capacity is lower than 80% of the 1C maximum discharge capacity of the alloy powder for 3 consecutive times, the charge-discharge cycle number when the discharge capacity reaches 80% is regarded as the cycle life. The test results are shown in Table 1.

[0034] Table 1

[0035] In the present invention, the hydrogen storage alloy involved is composed of three elements: nickel (Ni), zirconium (Zr), and lithium (Li). As an element with low electronegativity, lithium (Li) can effectively reduce the average electronegativity inside the alloy when added to the alloy. This effect of reducing electronegativity can further increase the hydrogen storage capacity of the alloy. In addition, by adding a small amount of zirconium (Zr) element to the alloy, the phase morphology of the alloy can be changed, thereby improving the stability of the crystal structure. This improvement in stability helps to reduce the lattice distortion phenomenon caused by the crystal structure transformation during the hydrogen absorption and desorption process of the alloy. Therefore, the addition of a trace amount of zirconium element has a significant promoting effect on enhancing the cycle stability of the alloy. At the same time, the strategy of partially replacing nickel (Ni) with lithium (Li) and zirconium (Zr) not only improves the mechanical properties of the alloy but also endows the alloy with a high hydrogen storage density, which is very beneficial for improving the hydrogen absorption capacity of the alloy. The present invention also adjusts the proportional relationship between alloy elements to achieve the precise substitution and combination of lithium (Li) and zirconium (Zr) atoms with nickel (Ni) atoms, thereby significantly improving the hydrogen storage capacity and cycle life of the hydrogen storage alloy.

[0036] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be regarded as limiting the claimed claim.

Claims

1. A method for preparing a high-capacity hydrogen storage alloy, characterized in that: The method comprises the following preparation steps: (1) The pure nickel powder is heated to a completely molten state, the electromagnetic stirring device set at the bottom of the smelting furnace is turned on, and the preheated metal zirconium powder is added. After ultrasonic stirring for 15 to 30 minutes, it is added into the gas atomization chamber for atomization to obtain Ni-Zr alloy powder; (2) The Ni-Zr alloy powder and pure lithium powder obtained in step (1) are subjected to high-energy ball milling treatment, and the powder is loaded into a mold for compression molding. Under argon protection, the powder is heat treated at 180-350° C. for 2-5 h, and then the temperature is raised to 400-600° C. and heat treated for 30 min to obtain a circular high-capacity hydrogen storage alloy electrode sheet with a diameter of 15 mm.

2. The method for preparing a high-capacity hydrogen storage alloy according to claim 1, characterized in that: The amount of pure nickel powder used is 50-65 parts by weight, the amount of metal zirconium powder used is 7-15 parts by weight, and the amount of pure lithium powder used is 20-35 parts by weight.

3. The method for preparing a high-capacity hydrogen storage alloy according to claim 1, characterized in that: In step (1), the preheating temperature of the metal zirconium powder is 600-650° C., and the preheating time is 10-30 min.

4. The method for preparing a high-capacity hydrogen storage alloy according to claim 1, characterized in that: The diameter of the metal zirconium powder in step (1) is 10-20 μm.

5. The method for preparing a high-capacity hydrogen storage alloy according to claim 1, characterized in that: In step (1), the atomizing medium is argon gas with a purity of more than 99.9%, the atomizing pressure is 0.5 MPa-10 MPa, and the flow rate is controlled at 4 L / min-20 L / min.

6. The method for preparing a high-capacity hydrogen storage alloy according to claim 1, characterized in that: In step (1), the frequency of the electromagnetic stirring device at the bottom of the smelting furnace is 2000~5000Hz.

7. The method for preparing a high-capacity hydrogen storage alloy according to claim 1, characterized in that: The particle size of the pure lithium powder in step (2) is 20-50 μm.

8. The method for preparing a high-capacity hydrogen storage alloy according to claim 1, characterized in that: The ball-to-material ratio used in the ball milling process in step (2) is 15:1, the ball milling is performed for 40 hours, and the rotation speed of the ball mill is selected to be 200 r / min.

9. The method for preparing a high-capacity hydrogen storage alloy according to claim 1, characterized in that: In step (2), the pressing pressure is 8-15 MPa, and the holding time is 0-30 s.

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