Y-Sm-Mg-Ni-based hydrogen storage alloy electrode material and preparation method thereof
Y-Sm-Mg-Ni hydrogen storage alloy electrode materials were prepared by Sm doping and intermediate alloy raw materials, which solved the problems of short cycle life and high cost of Y-Mg-Ni alloys and realized a high-capacity and long-life nickel-hydrogen battery anode material.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NINGBO SHENJIANG TECH
- Filing Date
- 2025-03-26
- Publication Date
- 2026-07-03
AI Technical Summary
Existing Y-Mg-Ni alloys have short cycle life in nickel-metal hydride batteries and are expensive to manufacture, making it difficult to meet the requirements of high safety and high capacity.
Y-Sm-Mg-Ni hydrogen storage alloy electrode materials were used. Sm doping was used to improve cycle stability. Y-Ni and Mg-Ni master alloys were used as raw materials. Electrode materials were prepared by combining induction melting and specific heat treatment processes to form AB3 type, A2B7 type and A5B19 type phase structures.
It significantly improves the cycle stability and hydrogen storage capacity of electrode materials, reduces the preparation cost, and the maximum discharge capacity of the battery anode material reaches 371mAh/g-382mAh/g at room temperature. After 100 charge-discharge cycles, the capacity retention rate reaches 89.5%-91.5%.
Smart Images
Figure CN120442993B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of hydrogen storage alloy technology, and in particular to a Y-Sm-Mg-Ni hydrogen storage alloy electrode material and its preparation method. Background Technology
[0002] Nickel-metal hydride (Ni-MH) batteries are rechargeable batteries favored for their high safety and environmental friendliness. While lithium-ion batteries are now widely used in many fields, Ni-MH batteries still offer significant advantages in certain aspects. Compared to lithium-ion batteries, Ni-MH batteries exhibit higher safety and a longer lifespan. Especially under overcharge or over-discharge conditions, Ni-MH batteries demonstrate greater stability and are less prone to safety issues, making them more attractive in applications with high safety standards. Furthermore, Ni-MH batteries have a longer cycle life, capable of withstanding more charge-discharge cycles, demonstrating greater economic efficiency in long-term use. Although lithium-ion batteries have an advantage in energy density, these characteristics of Ni-MH batteries in specific application scenarios make them an option that cannot be ignored.
[0003] The performance of nickel-metal hydride (NiMH) batteries largely depends on the hydrogen storage alloy of the anode material. The traditional anode material is the AB5 type hydrogen storage alloy, whose commercially available maximum discharge capacity is approximately 340 mAh / g, close to its theoretical maximum, which is insufficient to meet current market demands. Therefore, there is an urgent need to develop anode materials with higher capacity. In recent years, superlattice La-Mg / Y-Ni alloys have become a research hotspot and are considered potential candidate materials. However, compared to La-Mg / Y-Ni alloys, the newly discovered Y-Mg-Ni alloys, whose main components are the lightweight elements Y and magnesium (Mg), have a higher theoretical capacity. However, yttrium and magnesium readily react with the alkaline electrolyte in NiMH batteries, significantly reducing cycle life (References: Int J Hydrogen Energ 2018, 43(37):17800 and Int J Hydrogen Energ 2019, 44(39): 22064). Without improving the cycle life of Y-Mg-Ni alloys, they are difficult to use in NiMH batteries. Furthermore, elemental Y is expensive, approximately four times the price of Y-Ni alloys; meanwhile, Mg is prone to volatilization during the smelting process. A Y-Mg-Ni based alloy was prepared in CN115074578A by mixing alloy powder and Mg powder and then sintering. This alloy has a relatively stable phase structure consisting of a (Y,Mg,D)(Ni,E)2 phase (F-43m) and a (Y,Mg,D)(Ni,E)3 phase (R-3m). However, its cycling capacity decays rapidly, making it difficult to apply. Summary of the Invention
[0004] To address the aforementioned shortcomings, this invention proposes a Y-Sm-Mg-Ni hydrogen storage alloy electrode material and its preparation method. The Sm doping significantly improves the cycle stability of the Y-Mg-Ni alloy, and the preparation method reduces the preparation cost of the Y-Sm-Mg-Ni alloy by using Y-Ni and Mg-Ni master alloys as raw materials.
[0005] To achieve the above objectives, the present invention provides the following technical solution: a Y-Sm-Mg-Ni hydrogen storage alloy electrode material, wherein the chemical formula of the electrode material is Y 1-a-b Sm a Mg b Ni x Al y a, b, x, and y are atomic ratios, where 0.05≤a≤0.15, 0≤b≤0.2, 2.85≤x≤3.05, and 0≤y≤0.2.
[0006] As an improvement, 0.08≤a≤0.12 and 0≤y≤0.10.
[0007] As an improvement, electrode materials include AB3 type phase, A2B7 type phase, and A5B... 19 The AB3 phase is the dominant phase.
[0008] The preparation method of any of the above-mentioned Y-Sm-Mg-Ni system hydrogen storage alloy electrode materials includes the following steps:
[0009] S1: The as-cast alloy was prepared by using elemental metals, Y-Ni and Mg-Ni master alloys as raw materials and induction melting method.
[0010] S2: The as-cast alloy is wrapped and sealed in a quartz tube with an argon pressure of -0.09 to -0.05 MPa using tantalum sheets, and then heated uniformly from room temperature to the first temperature in a muffle furnace;
[0011] S3: Then, heat up to the second temperature at a constant rate and hold for 0.5-1.5 hours. Finally, heat up to the third temperature at a constant rate and hold for 4-8 hours. Then, cool naturally or in a water bath to room temperature and remove.
[0012] As an improvement, the first temperature in step S2 is 550℃-650℃, and the heating rate is 2-8℃ / min.
[0013] As an improvement, the second temperature in step S3 is 650℃-750℃, and the heating rate is 0.5-1.5℃ / min.
[0014] As an improvement, the third temperature in step S3 is 925℃~975℃, and the heating rate is 0.5-1.5℃ / min.
[0015] As an improvement, the nickel-metal hydride battery anode material prepared using the electrode material has a maximum discharge capacity of 371 mAh / g-382 mAh / g at room temperature, and a capacity retention rate of 89.5%-91.5% after 100 charge-discharge cycles.
[0016] Compared with the prior art, the advantages of the present invention are as follows:
[0017] (1) By doping with Sm, the cyclic stability of Y-Mg-Ni alloy was successfully improved. This improvement enabled the electrode material to maintain higher capacity stability during charge-discharge cycles and extended the battery life. Specifically, the maximum discharge capacity of the nickel-metal hydride battery anode material prepared using this electrode material reached 371 mAh / g to 382 mAh / g at room temperature, and its capacity retention rate was still maintained at a high level of 89.5% to 91.5% after 100 charge-discharge cycles.
[0018] (2) The alloy electrode material has the characteristic of high capacity, which is due to its fine phase structure design and optimized chemical composition ratio. The material contains AB3 type phase, A2B7 type phase and A5B... 19 The alloy has a combination of phases, with the AB3 phase being the main phase. This combination of phase structures enables the alloy to store and release hydrogen more effectively, thereby improving the hydrogen storage capacity and electrochemical performance of the electrode.
[0019] (3) Using Y-Ni and Mg-Ni intermediate alloys as raw materials significantly reduces the preparation cost of Y-Sm-Mg-Ni alloys. Traditional alloy preparation methods often require high-purity metallic elements as raw materials, which are costly. However, by using these intermediate alloys, not only is the cost of raw materials reduced, but the preparation process is also simplified and production efficiency is improved.
[0020] (4) The preparation method of this alloy electrode material is simple and easy to carry out, and it is easy to industrialize. The cast alloy is prepared by induction melting, and then a specific heat treatment process is used to obtain the electrode material with excellent performance. This preparation process is not only easy to control, but also has good repeatability, which provides a strong guarantee for large-scale production. Attached Figure Description
[0021] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:
[0022] Figure 1 This is a schematic diagram of the alloy phase structure in Example 1;
[0023] Figure 2 This is a schematic diagram of the alloy phase structure in Example 2;
[0024] Figure 3 This is a schematic diagram of the alloy phase structure in Example 3;
[0025] Figure 4 This is a schematic diagram of the alloy phase structure in Example 4;
[0026] Figure 5 This is a schematic diagram of the alloy phase structure for comparative example one. Detailed Implementation
[0027] Example 1
[0028] As shown in Table 1, S1 is prepared by using metallic elemental Sm, Ni, Al, Y-Ni and Mg-Ni master alloy as raw materials, wherein Sm is 1.75g, Ni is 4.27g, Al is 0.32g, Y-Ni is 22.24g and Mg-Ni is 1.42g, and the as-cast alloy is prepared by induction melting method.
[0029] S2: The as-cast alloy is wrapped and sealed in a quartz tube with tantalum sheet and argon pressure of -0.07 MPa, and then heated from room temperature to 600℃ in a muffle furnace at a heating rate of 5℃ / min.
[0030] S3: Then, the temperature is increased to 700℃ at a heating rate of 1℃ / min and held for 1 hour. Finally, the temperature is increased to 950℃ at a heating rate of 1℃ / min and held for 6 hours. Then, the temperature is naturally cooled or cooled to room temperature in a water bath to obtain the desired alloy, with a total alloy mass of 30g.
[0031] The chemical composition of this alloy electrode material is: Y 0.75 Sm 0.1 Mg 0.1 Ni 2.9 Al 0.1 The alloy electrode material was mechanically pulverized, then passed through a 400-mesh sieve. Its structure was tested using X-ray diffraction and analyzed using the Rietveld method. Figure 1 As shown, the alloy phase structure prepared in Example 1 is AB3 type phase and A2B7 type phase, with phase contents of 90.1% and 9.9%, respectively.
[0032] The pulverized alloy is passed through a 160-200 mesh sieve. 0.2g of alloy powder and 0.8g of nickel powder are weighed out and mixed evenly by grinding. The mixture is then placed into a mold with a diameter of 16mm and cold-pressed into an electrode sheet under a pressure of 10 MPa. The positive electrode is sintered nickel hydroxide (Ni(OH)2 / NiOOH), and the electrolyte is a 6mol / L KOH solution, thus forming a half-cell.
[0033] The test was conducted at room temperature (25℃) using a CT3004A battery tester. The test steps for the maximum discharge capacity of the alloy half-cell were as follows: First, the prepared half-cell was left to stand for 24 hours. Then, it was charged at a current density of 60 mA / g for 7.5 hours, left to stand for 10 minutes, and then discharged at a current density of 60 mA / g to 0.6 V. After standing for 10 minutes, the charge and discharge cycle was repeated until the maximum discharge capacity was reached. The maximum discharge capacity of Example 1 was 378 mAh / g.
[0034] Charge at a current density of 300 mA / g for 1.5 hours, let stand for 10 minutes, then discharge at a current density of 60 mA / g to 1.0V, let stand for 10 minutes, and record the discharge capacity of each charge-discharge cycle until the ratio of the discharge capacity to the maximum discharge capacity at 100 cycles is the capacity retention rate of the alloy. The capacity retention rate of Example 1 after 100 cycles is 84.6%.
[0035] Example 2
[0036] As shown in Table 1, S1 is prepared by using metallic elemental Sm, Ni, Al, Y-Ni and Mg-Ni master alloy as raw materials, wherein Sm is 2.56g, Ni is 4.88g, Al is 0.31g, Y-Ni is 20.19g and Mg-Ni is 2.07g, and the as-cast alloy is prepared by induction melting method.
[0037] The remaining steps are the same as in Example 1.
[0038] The chemical composition of this alloy electrode material is: Y 0.7 Sm 0.15 Mg 0.15 Ni 2.95 Al 0.11 ,like Figure 1 As shown, the alloy phase structure prepared in Example 2 is AB3 type phase, A2B7 type phase and A5B19 type phase, with phase contents of 81.2%, 10.3% and 8.5%, respectively.
[0039] The maximum discharge capacity of Example 2 is 371 mAh / g.
[0040] The capacity retention rate after 100 cycles in Example 2 was 91.5%.
[0041] Example 3
[0042] As shown in Table 1, S1 is prepared by using metallic elemental Sm, Ni, Al, Y-Ni and Mg-Ni master alloy as raw materials, wherein Sm is 2.08g, Ni is 3.37g, Al is 0.16g, Y-Ni is 23.13g and Mg-Ni is 1.26g, and the as-cast alloy is prepared by induction melting method.
[0043] The remaining steps are the same as in Example 1.
[0044] The chemical composition of this alloy electrode material is: Y 0.79 Sm 0.12 Mg 0.09 Ni 2.87 Al 0.05 ,like Figure 1 As shown, the alloy phase structure prepared in Example 3 is AB3 type phase and A2B7 type phase, with phase contents of 66.5% and 33.5%, respectively.
[0045] The maximum discharge capacity of Example 3 is 375 mAh / g.
[0046] The capacity retention rate after 100 cycles in Example 3 was 90.8%.
[0047] Example 4
[0048] As shown in Table 1, S1 is prepared by using metallic elemental Sm, Ni, Al, Y-Ni and Mg-Ni master alloy as raw materials, wherein Sm is 1.40g, Ni is 2.81g, Al is 0.63g, Y-Ni is 22.33g and Mg-Ni is 1.84g, and the as-cast alloy is prepared by induction melting method.
[0049] The remaining steps are the same as in Example 1.
[0050] The chemical composition of this alloy electrode material is: Y 0.79 Sm 0.08 Mg 0.13 Ni 2.85 Al 0.2 ,like Figure 1 As shown, the alloy phase structure prepared in Example 4 is AB3 type phase and A2B7 type phase, with phase contents of 71.3% and 28.7%, respectively.
[0051] The maximum discharge capacity of Example 4 is 382 mAh / g.
[0052] The capacity retention rate after 100 cycles in Example 4 was 89.5%.
[0053] Comparative Example 1
[0054] As shown in Table 1, S1: The raw materials are prepared by using metallic elemental Ni, Y-Ni and Mg-Ni master alloys, with Ni being 1.84g, Y-Ni being 25.97g and Mg-Ni being 1.84g, and the as-cast alloy is prepared by induction melting.
[0055] The remaining steps are the same as in Example 1.
[0056] The chemical composition of this alloy electrode material is: Y 0.85 Mg 0.15 Ni 2.9 ,like Figure 1 As shown, the alloy phase structure of the prepared comparative example is AB3 type phase with a phase content of 100%.
[0057] The maximum discharge capacity of Comparative Example 1 is 375 mAh / g.
[0058] The capacity retention rate of Comparative Example 1 after 100 cycles was 84.6%.
[0059] Table 1 lists the electrochemical performance of the hydrogen storage alloys described in Examples 1 to 4 and Comparative Example 1. As can be seen from Table 1, compared to Comparative Example 1, the addition of Sm and Al in Examples 1 to 4 significantly improved the cycle capacity retention of the alloy electrode material while maintaining the maximum discharge capacity of the electrode material.
[0060] Table 1 Electrochemical performance of Examples 1 to Comparative Examples 1
[0061]
[0062] The comparative example alloy has a single AB3-type phase structure. As is well known, the structural stability of the AB3-type phase is lower than that of the A2B7-type and A5B7-type phases. 19 Phase types. In Examples 1 to 4, after adding Sm and Al, the A2B7 and A5B phases appeared. 19 The presence of these phases improves the structural stability of the alloy electrode during cycling. Furthermore, literature studies have shown that Sm and Al can enhance the corrosion resistance of hydrogen storage electrode materials in alkaline electrolytes and slow down capacity decay of the alloy electrode (Int J Hydrogen Energ, 2021, 46(10): 7432, Int J Hydrogen Energ, 2025, 109: 264.). Therefore, compared to Comparative Example 1, Examples 1 to 4 improve the cycle capacity retention of the alloy electrode material in terms of both structural stability and oxidation corrosion resistance, while ensuring that the maximum discharge capacity remains essentially unchanged.
[0063] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the technical solution of the present invention, or the direct application of the concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.
Claims
1. A Y-Sm-Mg-Ni based hydrogen storage alloy electrode material, characterized in that: The chemical formula of the electrode material is Y. 1-a- b Sm a Mg b Ni x Al y a, b, x, and y are atomic ratios, where 0.05 ≤ a ≤ 0.15, 0 ≤ b ≤ 0.2, 2.85 ≤ x ≤ 3.05, and 0 ≤ y ≤ 0.
2. The preparation method of electrode material includes the following steps: S1: The as-cast alloy was prepared by using elemental metals, Y-Ni and Mg-Ni master alloys as raw materials and induction melting method. S2: The as-cast alloy is wrapped and sealed in a quartz tube with an argon pressure of -0.09 to -0.05 MPa using tantalum sheets, and then heated uniformly from room temperature to the first temperature in a muffle furnace; S3: Then, heat up to the second temperature at a constant rate and hold for 0.5-1.5 hours. Finally, heat up to the third temperature at a constant rate and hold for 4-8 hours. Then, cool naturally or in a water bath to room temperature and remove.
2. The Y-Sm-Mg-Ni hydrogen storage alloy electrode material according to claim 1, characterized in that: The values are 0.08≤a≤0.12 and 0≤y≤0.
10.
3. The Y-Sm-Mg-Ni hydrogen storage alloy electrode material according to claim 1, characterized in that: The electrode material consists of AB3 type phase, A2B7 type phase, and A5B... 19 The phase composition is such that the AB3 phase is the main phase.
4. The Y-Sm-Mg-Ni hydrogen storage alloy electrode material according to claim 1, characterized in that: The first temperature in step S2 is 550℃-650℃, and the heating rate is 2-8℃ / min.
5. The Y-Sm-Mg-Ni hydrogen storage alloy electrode material according to claim 1, characterized in that: The second temperature in step S3 is 650℃-750℃, and the heating rate is 0.5-1.5℃ / min.
6. The Y-Sm-Mg-Ni hydrogen storage alloy electrode material according to claim 1, characterized in that: The third temperature in step S3 is 925℃~975℃, and the heating rate is 0.5-1.5℃ / min.
7. The Y-Sm-Mg-Ni hydrogen storage alloy electrode material according to claim 1, characterized in that: The nickel-metal hydride battery anode material prepared using the electrode material has a maximum discharge capacity of 371 mAh / g-382 mAh / g at room temperature, and a capacity retention rate of 89.5%-91.5% after 100 charge-discharge cycles.