A method for preparing a low-cost, high-cycle-stability hydrogen storage alloy and its application.

Abstract

This application relates to the field of nickel-metal hydride battery technology, and more specifically, to a method for preparing and applying a low-cost, high-cycle-stability hydrogen storage alloy. The method includes the following steps: (1) preparing a La-Y-Ni alloy; (2) alloy annealing: heating the La-Y-Ni hydrogen storage alloy prepared by vacuum induction melting from room temperature to 950-1000℃, and performing a high-temperature annealing treatment at that temperature for 12-24 hours; (3) composite material preparation: placing MoS2 and alloy powder in a ball mill jar at a mass percentage ratio of 1-5:95-99, with a ball-to-material ratio of 97-103:1, introducing protective gas, and ball milling for 2-6 hours to obtain a MoS2 / La-Y-Ni low-temperature hydrogen storage alloy composite material. This method is simple, low-cost, and can effectively improve the discharge performance of the battery, resulting in a stable hydrogen storage alloy material.

Description

Technical Field

[0001] This application relates to the field of nickel-metal hydride battery technology, and more specifically, to a method for preparing a low-cost, high-cycle-stability hydrogen storage alloy and its application. Background Technology

[0002] Today, energy scarcity and various environmental problems are becoming increasingly prominent. Electrochemical conversion and storage technologies are crucial for addressing energy shortages, and the design of high-performance hydrogen evolution electrocatalysts and energy storage materials plays a vital role in the utilization of hydrogen energy. Among current energy development and utilization solutions, electrocatalytic hydrogen evolution reactions and nickel-metal hydride batteries show promising practical applications. Nickel-metal hydride batteries, as a high-energy green rechargeable battery, have also received extensive research attention. Therefore, the preparation of high-performance negative electrode hydrogen storage materials is key to improving energy conversion and storage methods.

[0003] La-Mg-Ni alloys have been a research hotspot both domestically and internationally in recent years due to their excellent hydrogen storage performance and high discharge capacity. However, their use as a negative electrode material in nickel-metal hydride batteries still faces some challenges. The low melting point (649℃) and high vapor pressure of magnesium cause it to easily volatilize and generate dust and potentially explode upon heating, posing significant safety hazards in industrial manufacturing. Commercially available AB5 alloy nickel-metal hydride batteries offer advantages such as low temperature, low self-discharge, and safety; however, the high cobalt content in the hydrogen storage alloy leads to a high cost, inevitably hindering its widespread application. Therefore, reducing the cost of current hydrogen storage alloys without compromising performance is a widely recognized and imperative goal. Summary of the Invention

[0004] This disclosure provides a method for preparing a low-cost, high-cycle-stability hydrogen storage alloy and its application. The method is simple, low-cost, and can effectively improve the discharge performance of the battery.

[0005] In a first aspect, this disclosure provides a method for preparing a low-cost, high-cycle-stability hydrogen storage alloy, comprising the following steps:

[0006] (1) Preparation of La-Y-Ni alloy: According to the mass ratio of La-Y-Ni alloy, each pure metal is placed in the melting furnace in order of melting point from low to high and from bottom to top and melted by conventional method to form alloy ingot with uniform composition.

[0007] (2) Alloy annealing treatment: The La-Y-Ni hydrogen storage alloy prepared by vacuum induction melting is heated from room temperature to 950-1000℃ and subjected to high-temperature annealing treatment for 12-24h.

[0008] (3) Preparation of composite material: MoS2 and alloy powder are placed in a ball mill jar at a mass percentage ratio of 1-5:95-99, with a ball-to-material ratio of 97-103:1. Protective gas is introduced, and the mixture is ball-milled for 2-6 hours to obtain MoS2 / La-Y-Ni system low-temperature hydrogen storage alloy composite material.

[0009] Preferably, in step (1), the specific preparation method is as follows: weigh the mass of Ni, Mn, Al and rare earth elements La, Nd and Y metal elements respectively, increase the burn-off amount of the easily volatile rare earth elements and Mn elements by 0.5% to 5% of the mass of the ingredients, and weigh the other alloy raw materials according to the stoichiometric ratio.

[0010] Preferably, in step (2), the specific processing method is as follows: after pouring each weighed metal raw material into a crucible, a vacuum is drawn to ensure that the gas pressure inside the melting furnace reaches at least 2×10⁻⁶. -3 The pressure is below MPa, and then argon gas is repeatedly introduced to clean the furnace to ensure that the furnace is in an oxygen-free environment. Argon gas is then introduced again, and the alloy sample is turned and melted 3-4 times in a non-consumable vacuum arc furnace under the protection of high-purity argon gas to ensure that each component is evenly distributed inside the alloy. After melting, the sample is cooled to obtain a hydrogen storage alloy. The prepared alloy ingot is heated to 900-1000℃ under the protection of 0.4MPa high-purity argon gas and held for 12-24 hours for annealing treatment.

[0011] Preferably, in step (3), a protective gas is introduced during annealing, and the protective gas is high-purity argon.

[0012] Secondly, this disclosure provides an application of a low-cost, high-cycle-stability hydrogen storage alloy. The application method is as follows: take the MoS2 / La-Y-Ni low-temperature hydrogen storage alloy composite material and carbonyl nickel, grind them in a mortar for 10-15 minutes, mix them evenly, place the powder in a mold, and cold press them into a circular electrode sheet at 12-18 MPa. The electrode sheet and nickel rod are welded together using a spot welding machine to serve as the negative electrode of a simulated battery. Sintered nickel hydroxide is used as the negative electrode of the simulated battery, and the electrolyte is a 6 mol / L potassium hydroxide solution.

[0013] Preferably, the mass ratio of the composite material to the carbonyl nickel powder is 1:5.

[0014] In summary, this application has the following beneficial effects:

[0015] 1. Because the composite hydrogen storage alloy prepared in this application has good activation performance, the material has excellent reversible hydrogen storage performance and a lifespan of more than 100 cycles.

[0016] 2. The hydrogen storage alloy composite material in this application has a hydrogen storage capacity of 600 mA·g at 30°C. -1Under current density, the rate discharge performance of ball milling for 4-6 hours can still be maintained above 60%;

[0017] 3. The materials for this application are readily available, the cost is low, the preparation process is simple and easy to control, and it has high feasibility. Moreover, it has certain application value for the development and utilization of rare earth resources.

[0018] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit the scope of protection of this disclosure. Attached Figure Description

[0019] 1. Figure 1 These are the XRD patterns of the hydrogen storage alloy materials prepared in Examples 1, 2, and 3 of this application;

[0020] 2. Figure 2 These are cycle stability curves of the composite hydrogen storage alloy materials prepared in Examples 1, 2, and 3 of this application;

[0021] 3. Figure 3 The rate discharge performance of the composite hydrogen storage alloys prepared in Examples 1, 2, and 3 of this application is shown. Detailed Implementation

[0022] The following detailed description of this application is provided in conjunction with the embodiments. It should be noted that: unless otherwise specified, the conditions in the following embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following embodiments are all from commercially available sources.

[0023] Example

[0024] Example 1

[0025] (1) Alloy preparation

[0026] Press La 0.1 Nd 0.4 Y 0.5 Ni 2.75 Mn 0.3 Al 0.2 The stoichiometric proportions of the molecular formulas were used to calculate the mass of each element. The masses of Nd, Y, Ni, Mn, and Al metals with a purity of 99.9% were weighed separately. Since Mn, Nd, and Y metals will be lost during smelting, an additional 0.5-5% should be added when weighing the raw materials to compensate for the loss. The metals were placed in the smelting furnace in order of increasing melting point from bottom to top, in copper crucibles cooled and protected by circulating water. The pressure inside the furnace was evacuated to 2 × 10⁻⁶. - 3Below MPa, argon gas is introduced and the furnace is repeatedly washed at least three times. Each time the furnace is washed, high-purity argon gas is introduced to bring the internal pressure to -0.05 MPa, and the melting current is 90–110 A. During alloy melting, to ensure uniform distribution of the components within the alloy, the alloy ingot is turned over at least three times and remelted four times. The prepared alloy ingot is heated to 1000℃ under a 0.4 MPa high-purity argon atmosphere at a heating rate of 2–4 min / ℃, held for 24 h, and then annealed. The treated alloy is then mechanically crushed and ground, and sieved through a 200–400 mesh sieve to prepare La. 0.1 Nd 0.4 Y 0.5 Ni 2.75 Mn 0.3 Al 0.2 alloy powder.

[0027] (2) Preparation of MoS2 alloy composite materials

[0028] MoS2 powder and alloy powder were mixed at a mass ratio of 1:99 in a ball mill jar, and ball milled for 2 hours at a ball-to-powder ratio of 100:1 under argon protection to obtain La. 0.1 Nd 0.4 Y 0.5 Ni 2.75 Mn 0.3 Al 0.2 / MoS2 hydrogen storage alloy composite material.

[0029] (3) Simulated battery assembly

[0030] Take the above La 0.1 Nd 0.4 Y 0.5 Ni 2.75 Mn 0.3 Al 0.2 MoS2 hydrogen storage alloy material and carbonyl nickel (the mass ratio of composite material to carbonyl nickel powder is 1:5) are ground in a mortar for 10-15 minutes to ensure uniform mixing. The mixture is then placed in a mold and cold-pressed at 12-18 MPa to form a circular electrode sheet. This electrode sheet is then welded to a nickel rod using a spot welder to serve as the negative electrode of a simulated battery. Sintered nickel hydroxide is used as the negative electrode in the simulated battery, and a 6 mol / L potassium hydroxide solution is used as the electrolyte. The simulated battery is then connected to a Land battery tester to test its cycle life, high-rate discharge, and other electrochemical performance.

[0031] (3) Performance Testing

[0032] When determining cycle life, both the charging and discharging current densities were 60 mA / g. When determining rate performance, the charging current density was 60 mA / g, and the discharging current densities were successively set to 60 mA / g, 120 mA / g, 180 mA / g, and 600 mA / g.

[0033] like Figure 2 As shown, the composite hydrogen storage alloy after ball milling retains about 40% of its capacity after 100 cycles.

[0034] Example 2

[0035] (1) Alloy preparation

[0036] Press La 0.1 Nd 0.4 Y 0.5 Ni 2.75 Mn 0.3 Al 0.2 The stoichiometric proportions of the molecular formulas were used to calculate the mass of each element. The masses of Nd, Y, Ni, Mn, and Al metals with a purity of 99.9% were weighed separately. Since Mn, Nd, and Y metals will be lost during smelting, an additional 0.5–5% should be added when weighing the raw materials to compensate for the loss. The metals were placed in the smelting furnace in order of increasing melting point from bottom to top, in copper crucibles cooled and protected by circulating water. The pressure inside the furnace was evacuated to 2 × 10⁻⁶. -3 Below MPa, argon gas is introduced and the furnace is repeatedly washed at least three times. Each time the furnace is washed, high-purity argon gas is introduced to bring the internal pressure to -0.05 MPa, and the melting current is 90–110 A. During alloy melting, to ensure uniform distribution of the components within the alloy, the alloy ingot is turned over at least three times and remelted four times. The prepared alloy ingot is heated to 1000℃ and held for 24 hours under a 0.4 MPa high-purity argon protective atmosphere for annealing. The treated alloy is then mechanically crushed and ground, and sieved through a 200–400 mesh sieve to prepare La. 0.1 Nd 0.4 Y 0.5 Ni 2.75 Mn 0.3 Al 0.2 alloy powder.

[0037] (2) Preparation of MoS2 alloy composite materials

[0038] MoS2 powder and alloy powder were placed in a ball mill jar at a mass ratio of 1:99, and ball milled for 4 hours at a ball-to-powder ratio of 100:1 under argon protection to obtain La. 0.1 Nd 0.4 Y 0.5 Ni 2.75 Mn 0.3 Al0.2 / MoS2 hydrogen storage alloy composite material.

[0039] (3) Simulated battery assembly

[0040] Take the above La 0.1 Nd 0.4 Y 0.5 Ni 2.75 Mn 0.3 Al 0.2 MoS2 hydrogen storage alloy material and carbonyl nickel (the mass ratio of composite material to carbonyl nickel powder is 1:5) are ground in a mortar for about 10 minutes to ensure uniform mixing. The mixture is then placed in a mold and cold-pressed at 12-18 MPa to form a circular electrode sheet. This electrode sheet is then welded to a nickel rod using a spot welder to serve as the negative electrode of a simulated battery. Sintered nickel hydroxide is used as the negative electrode in the simulated battery, and a 6 mol / L potassium hydroxide solution is used as the electrolyte. The simulated battery is then connected to a Land battery tester to test its cycle life, high-rate discharge, and other electrochemical performance.

[0041] (4) Performance Testing

[0042] When determining cycle life, both the charging and discharging current densities were 60 mA / g. When determining rate performance, the charging current density was 60 mA / g, and the discharging current densities were successively set to 60 mA / g, 120 mA / g, 180 mA / g, and 600 mA / g.

[0043] like Figure 2 As shown, the composite hydrogen storage alloy after ball milling still retains more than 90% of its capacity after 100 cycles.

[0044] Example 3

[0045] (1) Alloy preparation

[0046] Press La 0.1 Nd 0.4 Y 0.5 Ni 2.75 Mn 0.3 Al 0.2 The stoichiometric proportions of the molecular formulas were used to calculate the mass of each element. The masses of Nd, Y, Ni, Mn, and Al metals with a purity of 99.9% were weighed separately. Since Mn, Nd, and Y metals will be lost during smelting, an additional 0.5-5% should be added when weighing the raw materials to compensate for the loss. The metals were placed in the smelting furnace in order of increasing melting point from bottom to top, in copper crucibles cooled and protected by circulating water. The pressure inside the furnace was evacuated to 2 × 10⁻⁶. - 3Below MPa, argon gas is introduced and the furnace is repeatedly washed at least three times. Each time the furnace is washed, high-purity argon gas is introduced to bring the internal pressure to -0.05 MPa, and the melting current is 90–110 A. During alloy melting, to ensure uniform distribution of the components within the alloy, the alloy ingot is turned over at least three times and remelted four times. The prepared alloy ingot is heated to 1000℃ and held for 24 hours under a 0.4 MPa high-purity argon protective atmosphere for annealing. The treated alloy is then mechanically crushed and ground, and sieved through a 200–400 mesh sieve to prepare La. 0.1 Nd 0.4 Y 0.5 Ni 2.75 Mn 0.3 Al 0.2 alloy powder.

[0047] (2) Preparation of MoS2 alloy composite materials

[0048] MoS2 powder and alloy powder were placed in a ball mill jar at a mass ratio of 1:99, and ball milled for 6 hours at a ball-to-powder ratio of 100:1 under argon protection to obtain La. 0.1 Nd 0.4 Y 0.5 Ni 2.75 Mn 0.3 Al 0.2 / MoS2 hydrogen storage alloy composite material.

[0049] (3) Simulated battery assembly

[0050] Take the above La 0.1 Nd 0.4 Y 0.5 Ni 2.75 Mn 0.3 Al 0.2 MoS2 hydrogen storage alloy material and carbonyl nickel (the mass ratio of composite material to carbonyl nickel powder is 1:5) are ground in a mortar for about 10 minutes to ensure uniform mixing. The mixture is then placed in a mold and cold-pressed at 12-18 MPa to form a circular electrode sheet. This electrode sheet is then welded to a nickel rod using a spot welder to serve as the negative electrode of a simulated battery. Sintered nickel hydroxide is used as the negative electrode in the simulated battery, and a 6 mol / L potassium hydroxide solution is used as the electrolyte. The simulated battery is then connected to a Land battery tester to test its cycle life, high-rate discharge, and other electrochemical performance.

[0051] (4) Performance Testing

[0052] When determining cycle life, both the charging and discharging current densities were 60 mA / g. When determining rate performance, the charging current density was 60 mA / g, and the discharging current densities were successively set to 60 mA / g, 120 mA / g, 180 mA / g, and 600 mA / g.

[0053] like Figure 2 As shown, the composite hydrogen storage alloy after ball milling still retains more than 90% of its capacity after 100 cycles.

[0054] The above description is merely an exemplary embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.

Claims

1. A method for preparing a low-cost high-cycle-stability hydrogen storage alloy, characterized by, The method comprises the following steps: (1) preparing La-Y-Ni alloy: placing pure metals in a melting furnace from low to high melting point according to the mass ratio of La-Y-Ni alloy, and melting by a conventional method to form an alloy ingot with uniform composition; (2) annealing treatment of the alloy: heating the La-Y-Ni hydrogen storage alloy prepared by vacuum induction melting from room temperature to 950-1000 °C at a heating rate of 2-4 min / °C, and performing high-temperature annealing treatment at the temperature for 12-24 h; (3) preparing the composite material: placing MoS2 and alloy powder in a ball mill tank according to the mass ratio of 1-5:95-99, ball-to-material ratio of 97-103:1, and introducing protective gas, and ball milling for 4-6 hours to obtain the MoS2 / La-Y-Ni low-temperature hydrogen storage alloy composite material; In step (1), the La-Y-Ni alloy is of the formula La 0.1 Nd 0.4 Y 0.5 Ni 2.75 Mn 0.3 Al 0.2 ; The capacity retention rate of the hydrogen storage alloy composite material prepared by ball milling in step (3) reaches 90% after 100 cycles.

2. The method for preparing a low-cost, high-cycle-stability hydrogen storage alloy according to claim 1, characterized in that, In step (1), the specific preparation method is: weighing the mass of Ni, Mn, Al, and rare earth elements La, Nd, and Y metal elements, adding a burning loss of 0.5%-5% of the mass of the volatile rare earth elements and the Mn element, and weighing other alloy raw materials according to the stoichiometric ratio.

3. The method for preparing a low-cost, high-cycle-stability hydrogen storage alloy according to claim 2, characterized in that, In the step (2), the specific processing method is: after each metal raw material is poured into the crucible, vacuum is extracted, the air pressure in the smelting furnace is at least 2×10 -3 MPa or below, then argon is filled repeatedly to wash the furnace to ensure that the furnace is in an oxygen-free environment, then argon is introduced, and the alloy sample is turned over and smelted 3-4 times by using a non-consumable vacuum arc furnace under the protection of high-purity argon, so as to ensure that each component is uniformly distributed in the alloy, and the smelting is completed to obtain a hydrogen storage alloy; and the prepared alloy ingot is annealed under the protection of 0.4 MPa high-purity argon.

4. The method of claim 1, wherein the low-cost high-cycle-stability hydrogen storage alloy is prepared by the steps of: preparing a master alloy by mixing a magnesium alloy and a rare earth alloy; and adding a small amount of a transition metal to the master alloy. In step (3), a protective gas is filled during annealing, and the protective gas is high-purity argon.

5. Use of a low-cost high-cycle-stable hydrogen storage alloy according to any one of claims 1 to 4, characterized in that The application method is: grinding the MoS2 / La-Y-Ni low-temperature hydrogen storage alloy composite material and carbonyl nickel in a mortar for 10-15 min, mixing uniformly, placing the powder in a mold, cold pressing into a circular electrode sheet under a pressure of 12-18 MPa, welding the electrode sheet and a nickel rod together using a spot welding machine as the negative electrode of a simulated battery, using sintered nickel hydroxide as the negative electrode of the simulated battery, and using a 6 mol / L potassium hydroxide solution as the electrolyte.

6. Use of a low cost high cycle stability hydrogen storage alloy according to claim 5, characterized in that, The mass ratio of the composite material to the carbonyl nickel powder is 1:5.

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