A method for preparing Mg-Ni-based hydrogen storage alloy containing rare earth elements
By using vacuum induction melting and rare earth element modification, a Mg-Ni-based hydrogen storage alloy was prepared, which solved the problems of high hydrogen release temperature and low hydrogen storage capacity of magnesium-based hydrogen storage materials, and achieved improved high-efficiency hydrogen storage performance and industrial application.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHANGCHUN INSTITUTE OF APPLIED CHEMISTRY CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2024-02-07
- Publication Date
- 2026-05-26
AI Technical Summary
Existing magnesium-based hydrogen storage materials have excessively high hydrogen release temperatures and low platform pressures, which limit their hydrogen storage capacity and make it difficult to meet the needs of industrial applications.
Mg-Ni based hydrogen storage alloys were synthesized using a vacuum induction melting process. Rare earth elements La and Y were added, and their contents were adjusted to improve the kinetic properties of the alloys. The synthesis was carried out using high-purity SF6 gas in an oxygen-free environment.
This method improves the hydrogen storage performance of Mg-Ni based hydrogen storage alloys, reduces the peak hydrogen desorption temperature, increases hydrogen storage capacity, and has a simple process that is easy to scale up for industrial production.
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Figure CN118147466B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for preparing a Mg-Ni-based hydrogen storage alloy containing rare earth elements, belonging to the technical field of hydrogen storage alloy materials and their preparation. Background Technology
[0002] Hydrogen, with its abundant reserves, high energy value, and environmentally friendly nature, is considered the most promising energy carrier of the 21st century and a key direction for human energy strategy. In the industrial application of hydrogen energy, hydrogen storage and transportation are crucial links connecting upstream hydrogen production and downstream hydrogen consumption. High-pressure gaseous hydrogen storage, cryogenic liquid hydrogen storage, and solid-state hydrogen storage are three main methods. Considering factors such as volumetric hydrogen storage density, energy consumption, and safety, metal-based hydrogen storage materials are currently recognized as one of the best methods. Magnesium-based hydrogen storage materials, with their advantages of low cost, excellent reversibility, high hydrogen storage capacity, and abundant elemental reserves, are considered among the most promising and worthy of research. However, the Mg-H bond is too stable, with a hydrogen release enthalpy change of approximately 75 kJ / mol, resulting in an excessively high hydrogen release temperature. Furthermore, the relatively low plateau pressure of magnesium-based hydrogen storage materials limits their hydrogen storage capacity. Therefore, it is essential to find a way to effectively improve the hydrogen absorption and desorption properties of magnesium-based alloys and provide an ideal magnesium-based hydrogen storage material that is feasible for large-scale industrial application and can be used for future hydrogen storage and transportation. Summary of the Invention
[0003] In order to solve the problems of activation and limited hydrogen storage capacity of existing hydrogen storage materials, this invention provides a method for preparing Mg-Ni-based hydrogen storage alloy containing rare earth elements.
[0004] The technical solution of the present invention:
[0005] One of the objectives of this invention is to provide a method for preparing a Mg-Ni-based hydrogen storage alloy containing rare earth elements, specifically using elemental metals as raw materials, which are then forged after vacuum induction melting.
[0006] Further specifying, the preparation method includes the following steps:
[0007] (1) Weigh the elemental metals Mg, Ni, La and Y according to the chemical formula of the hydrogen storage alloy;
[0008] (2) After mixing all the metal elements weighed in step (1) evenly, put them into the melting crucible and cover the crucible with the lid;
[0009] (3) Heat the melting crucible to 400-500℃, keep it at that temperature for 2-3 minutes, and then introduce SF6 gas to replace the air;
[0010] (4) While maintaining the SF6 gas flow, heat to 1000-1050℃ and hold for 3-5 minutes, then continue to heat to 1100-1150℃ and hold for 10 minutes, then cast to obtain the hydrogen storage alloy.
[0011] Further specified, (1) is to add an additional 5 wt.% of Mg metal element in the raw material.
[0012] Further specified, (1) additionally adds 1 wt.% of Y metal element in the raw material.
[0013] Further specified, (1) additionally adds 1 wt.% of La metal element in the raw material.
[0014] Further specifying, the purity of SF6 gas in (3) and (4) is 99.9%.
[0015] Furthermore, the Mg-Ni-based hydrogen storage alloy containing rare earth elements prepared by the above method has the chemical formula Mg 3.497 Ni 0.170 La x Y y , where 0.0280≤x≤0.0360, 0≤y≤0.012.
[0016] To further specify, x is 0.032 and y is 0.006.
[0017] To further specify, x is 0.028 and y is 0.012.
[0018] To further specify, x is 0.036 and y is 0.
[0019] Furthermore, the hydrogen storage alloy has a hydrogen storage capacity of 4.645 wt.% at 220°C and 5 MPa.
[0020] Beneficial effects:
[0021] This invention modifies Mg-Ni-based hydrogen storage alloys using the rare earth element La. The modified Mg 3.497 Ni 0.170 La 0.036 The hydrogen storage performance of the hydrogen storage alloy was significantly improved. Further improvements were made in Mg... 3.497 Ni 0.170 La 0.036Based on the alloy, La was substituted with rare earth element Y. By adjusting the content of rare earth elements Y and La, the kinetic properties of the alloy were enhanced, and the hydrogen storage capacity was improved. The peak hydrogen desorption temperature of the hydrogen storage alloy after substitution was reduced to 273℃. Furthermore, the addition of rare earth elements La and Y not only improves the performance of the hydrogen storage alloy, but also has significant implications for the high-value utilization of abundant rare earth elements in my country.
[0022] Meanwhile, this invention utilizes a vacuum induction melting process to synthesize Mg-Ni-based hydrogen storage alloys by injecting 99.9% high-purity SF6 into a melting furnace under an oxygen-free environment. This method has a simple preparation process, uses equipment commonly found in non-ferrous metal smelting enterprises, and is simple, stable, and easy to promote on a large scale in industry. The resulting Mg-Ni-based hydrogen storage alloy is expected to become an excellent hydrogen storage alloy for future applications such as hydrogen storage, transportation, hydrogen fuel cells, and hydrogen-powered engines. Attached Figure Description
[0023] Figure 1 The hydrogen storage alloys prepared in Examples 1-3 are shown in the first hydrogen absorption kinetic curves at 220°C and 5 MPa.
[0024] Figure 2 The hydrogen storage alloys prepared in Examples 1-3 are shown as the first hydrogen release kinetic curves under conditions of 280°C and 0.01 MPa.
[0025] Figure 3 The graphs show the hydrogen absorption and desorption PCT test curves of the hydrogen storage alloys prepared in Examples 1-3 at 260℃, 280℃, 300℃, and 320℃.
[0026] Figure 4 The hydrogen storage alloy prepared in Example 1 is shown in the DSC test curves of hydrogen desorption of the alloy under heating rates of 5℃ / min, 10℃ / min, 15℃ / min, and 20℃ / min.
[0027] Figure 5 The hydrogen storage alloy prepared in Example 2 is shown in the DSC test curves of hydrogen desorption of the alloy under heating rates of 5℃ / min, 10℃ / min, 15℃ / min, and 20℃ / min.
[0028] Figure 6 The hydrogen storage alloy prepared in Example 3 is shown in the DSC test curves of hydrogen desorption of the alloy under heating rates of 5℃ / min, 10℃ / min, 15℃ / min, and 20℃ / min.
[0029] Figure 7 The XRD patterns of the hydrogen storage alloys prepared in Examples 1-3 are shown below.
[0030] Figure 8The backscattering pattern of the hydrogen storage alloy prepared in Example 1;
[0031] Figure 9 The backscattering pattern of the hydrogen storage alloy prepared in Example 2;
[0032] Figure 10 The backscattering pattern of the hydrogen storage alloy prepared in Example 3;
[0033] Figure 11 The image shows the mapping results corresponding to the backscattering of the hydrogen storage alloy prepared in Example 2. Detailed Implementation
[0034] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.
[0035] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.
[0036] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.
[0037] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.
[0038] Example 1:
[0039] The Mg-Ni-based hydrogen storage alloy prepared in this embodiment has the chemical formula Mg 3.497 Ni 0.170 La 0.036 .
[0040] The method for preparing the above-mentioned Mg-Ni-based hydrogen storage alloy in this embodiment includes the following steps:
[0041] a. According to Mg 3.497 Ni 0.170 La 0.036Based on the atomic ratios, the mass of each element was calculated. The masses of Mg, Ni, and La metals with a purity of 99.9% were weighed separately. Since Mg metal will be lost during smelting, an additional 5% mass should be added when weighing the raw materials to compensate for the loss. The specific weighing values are as follows: Mg: 44.625g, Ni: 5.028g, La: 4.011g, for later use. Mg, Ni, and La metals are used as raw materials.
[0042] b. Applying vacuum induction melting process, to ensure the accuracy of alloy melting, firstly, all metal element surfaces from step a are polished to remove the oxide film; before melting, the inner wall of the melting furnace must also be wiped clean with alcohol cotton. Each weighed alloy sample is preheated and dried, then placed in a melting crucible inside the melting furnace, and the crucible lid is then closed; the melting crucible is heated to 400-500℃ and held for 2-3 minutes, then SF6 gas is introduced to replace the air; after the air is replaced, SF6 gas is continued to be introduced, and the melting furnace is heated to 1000-1050℃ and held for 3-5 minutes; the melting crucible furnace is then further heated to 1100-1150℃ and held for 10 minutes before casting.
[0043] Example 2:
[0044] The difference between this embodiment and Embodiment 1 is that Y is used instead of 0.5 wt.% La, and the chemical formula of its hydrogen storage alloy is Mg. 3.497 Ni 0.170 La 0.032 Y 0.006 The specific weighing values are as follows: Mg: 45.0132g, Ni: 5.1112g, La: 3.7875g, Y: 0.2525g (where Mg, La, and Y are easily volatilized during the smelting process, therefore 5% more Mg and 1% more La and Y should be weighed to compensate for the loss due to burning). The remaining process steps and parameter settings are the same as in Example 1, and Mg is obtained. 3.497 Ni 0.170 La 0.032 Y 0.006 Hydrogen storage alloy ingot.
[0045] Example 3:
[0046] The difference between this embodiment and Embodiment 1 is that Y is used instead of 1 wt.% La, and the chemical formula of its hydrogen storage alloy is Mg. 3.497 Ni 0.170 La 0.028 Y 0.012The specific weighing values are as follows: Mg: 45.058g, Ni: 5.0194g, La: 3.535g, Y: 0.505g (where Mg, La, and Y are easily volatilized during the smelting process, therefore 5% more Mg and 1% more La and Y should be weighed to compensate for the loss due to burning). The remaining process steps and parameter settings are the same as in Example 1, and Mg is obtained. 3.497 Ni 0.170 La 0.028 Y 0.012 Hydrogen storage alloy ingot.
[0047] Example of results:
[0048] (1) The Mg-Ni-based hydrogen storage alloy ingots prepared in Examples 1-3 were polished with a grinder to remove the surface oxide layer. The alloys were then ground and pulverized through a 200-mesh sieve to obtain hydrogen storage alloy powder. Approximately 0.5g of the prepared hydrogen storage alloy powder was placed into the reaction vessel of the PCT equipment. The reaction vessel was evacuated to below 0.0001MPa, and hydrogen gas with a purity of 99.9% was introduced. The hydrogen pressure was increased to 5MPa, and the hydrogen absorption / desorption kinetics of the alloy were tested. The test results are as follows: Figure 1 As shown in the figure. It can be seen from the figure that the Mg prepared in Example 2... 3.497 Ni 0.170 La 0.032 Y 0.006 Under the conditions of 220℃ and 5MPa, the kinetic performance is optimal, with 3.35wt.% hydrogen absorbed within 1 minute of the first hydrogen absorption and a hydrogen storage capacity of 4.645wt.%.
[0049] (2) The isothermal hydrogen desorption performance of the Mg-Ni-based hydrogen storage alloys prepared in Examples 1-3 was tested at 280℃, and the results are as follows: Figure 2 As shown in the figure, Mg 3.497 Ni 0.170 La 0.032 Y 0.006 The hydrogen release kinetics were optimal at 280℃ and 0.01MPa, with 1.834 wt.% hydrogen released in 1 min, while Example 3 released 1.431 wt.% hydrogen in 1 min and Example 1 released 0.96 wt.% hydrogen in 1 min.
[0050] (3) Test the Mg prepared in Example 1 3.497 Ni 0.170 La 0.036 The hydrogen desorption performance of the alloy at heating rates of 5℃ / min, 10℃ / min, 15℃ / min, and 20℃ / min is shown in the following results. Figure 4 As shown, by Figure 4It can be seen that the peak hydrogen release temperatures of the alloy at different heating rates are 336.1℃, 352.0℃, 365.1℃ and 371.2℃, respectively.
[0051] (4) Test the Mg prepared in Example 2 3.497 Ni 0.170 La 0.032 Y 0.006 The hydrogen desorption performance of the alloy at heating rates of 5℃ / min, 10℃ / min, 15℃ / min, and 20℃ / min is shown in the following results. Figure 5 As shown, by Figure 5 It can be seen that the peak hydrogen release temperatures of the alloy at different heating rates are 273.3℃, 288.3℃, 298.6℃ and 312.3℃, respectively.
[0052] (5) Test the Mg prepared in Example 3 3.497 Ni 0.170 La 0.028 Y 0.012 The hydrogen desorption performance of the alloy at heating rates of 5℃ / min, 10℃ / min, 15℃ / min, and 20℃ / min is shown in the following results. Figure 6 As shown, by Figure 6 It can be seen that the peak hydrogen release temperatures of the alloy at different heating rates are 324.6℃, 339.6℃, 349.0℃ and 361.9℃, respectively.
[0053] (6) The Mg-Ni-based hydrogen storage alloys prepared in Examples 1-3 were characterized by XRD using a Bruker D8 Advance X, Cu Kα, 40kV, 40mA instrument. The results are as follows: Figure 7 As shown in the figure, the Mg-Ni-based hydrogen storage alloys prepared in Examples 1-3 mainly exhibit Mg diffraction peaks, with the remaining phases being Mg2Ni and La2Mg. 17 Furthermore, the Mg-Ni-based hydrogen storage alloys prepared in Examples 2 and 3 contain diffraction peaks of the MgY phase.
[0054] (7) The Mg prepared in Example 1 3.497 Ni 0.170 La 0.036 Backscattering analysis of the alloy yielded the following results: Figure 8 As shown in the figure, the black part is the Mg phase, the dendritic gray phase is Mg2Ni, and the light gray blocky phase is La2Mg. 17 Mutually.
[0055] (8) The Mg prepared in Example 2 3.497 Ni 0.170 La 0.032 Y 0.006Backscattering analysis was performed, and the results are as follows: Figure 9 As shown, Figure 11 This is the mapping diagram corresponding to the backscattering results. As shown in the diagram, the black area represents the Mg phase, the dendritic gray phase is Mg2Ni, and the light gray blocky phase is La2Mg. 17 The white lumps are Y phase, and scattering results indicate that there is a small amount of Y element accumulation.
[0056] (9) The Mg prepared in Example 3 3.497 Ni 0.170 La 0.028 Y 0.012 Backscattering analysis was performed, and the results are as follows: Figure 9 As shown in the figure, the black part is the Mg phase, the dendritic gray phase is Mg2Ni, and the light gray blocky phase is La2Mg. 17 The white lumps are Y phase. Scattering results show that there is a lot of Y element accumulation. This is because when La is replaced by rare earth element Y, when the amount of Y doping is too much, the Y-containing compounds in the alloy cannot be uniformly dispersed during solidification. Instead, they solidify and crystallize into larger lamellae or gather at the grain boundaries, which is not conducive to the refinement of alloy grains. This is also the reason for the weakening of the alloy's hydrogen storage performance.
[0057] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.
Claims
1. A method for preparing a Mg-Ni-based hydrogen storage alloy containing rare earth elements, characterized in that, Includes the following steps: (1) Weigh the Mg, Ni, La and Y metal elements according to the chemical formula of the hydrogen storage alloy; add Mg metal element of 5 wt.% of the Mg metal element in the raw materials; add Y metal element of 1 wt.% of the Y metal element in the raw materials; add La metal element of 1 wt.% of the La metal element in the raw materials; (2) After mixing all the metal elements weighed in step (1) evenly, put them into the melting crucible and cover the crucible with the lid; (3) Heat the melting crucible to 400-500℃, keep it at that temperature for 2-3 minutes, and then introduce SF6 gas to replace the air; (4) Under the condition of SF6 gas being introduced, the temperature is raised to 1000-1050℃ and held for 3-5 minutes, then the temperature is raised to 1100-1150℃ and held for 10 minutes, and then cast to obtain hydrogen storage alloy. The prepared Mg-Ni-based hydrogen storage alloy containing rare earth elements has the chemical formula Mg 3.497 Ni 0.170 La x Y y Where 0.0288≤x<0.0360, 0 <y≤0.012。 2. The preparation method according to claim 1, characterized in that, x is 0.032 and y is 0.
006.
3. The preparation method according to claim 1, characterized in that, x is 0.028 and y is 0.
012.
4. The preparation method according to claim 1, characterized in that, The prepared Mg-Ni-based hydrogen storage alloy containing rare earth elements has a hydrogen storage capacity of 4.645 wt.% at 220℃ and 5 MPa.