High-capacity solid solution type magnesium-based hydrogen storage alloy capable of absorbing hydrogen at low temperature and preparation method of high-capacity solid solution type magnesium-based hydrogen storage alloy
By alloying Sc to form a MgSc solid solution alloy, the problems of low-temperature hydrogen absorption and cycle stability of magnesium-based hydrogen storage materials are solved, achieving high-efficiency hydrogen storage performance and stable kinetic performance, which is suitable for large-scale industrial production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-31
- Publication Date
- 2026-04-03
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
Magnesium-based hydrogen storage materials have difficulty absorbing hydrogen at low temperatures, have high hydrogen release temperatures, poor cycle stability, and poor kinetic performance.
Rare earth element Sc is used for alloying to form MgSc solid solution alloy. Through the solid solution effect of Sc and the in-situ ScH2 nano-catalytic phase, the diffusion of hydrogen atoms and structural stability are improved. Combined with resistance melting technology, the proportion of alloying elements is precisely controlled.
It maintains good hydrogen absorption performance at low temperatures, significantly improves hydrogen absorption and desorption kinetics and cycle stability, and is suitable for large-scale industrial production.
Smart Images
Figure CN121780959A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a high-capacity solid solution magnesium-based hydrogen storage alloy for low-temperature hydrogen absorption and its preparation method. Background Technology
[0002] Hydrogen energy boasts advantages such as abundant resources, high energy density, and clean, pollution-free operation, making it significant in replacing traditional fossil fuels. The safe and efficient storage and transportation of hydrogen are crucial links and major challenges for the large-scale application of hydrogen energy. Solid-state hydrogen storage technology, characterized by high hydrogen storage density and good safety, is a promising hydrogen storage technology. Magnesium-based hydrogen storage materials have attracted considerable attention due to their high hydrogen storage capacity (7.6 wt.%) and abundant resources. However, their practical application still faces key challenges such as difficulty in hydrogen absorption at low temperatures, high hydrogen release temperatures, and poor cycle stability.
[0003] To improve the hydrogen storage performance of magnesium-based materials, current research mainly focuses on three aspects: alloying, nano-sizing and nano-confining, and external doping catalysts. Among these, adding alloying elements can form new magnesium-based hydrides or rare-earth hydrides, reducing the thermodynamic stability of the hydrides by altering the reaction pathway or weakening the Mg-H bond, and improving kinetics by lowering the apparent activation energy. Considering engineering applications and low-cost manufacturing, alloying is a simple and efficient way to improve the hydrogen storage performance of magnesium-based materials. However, the biggest drawback of alloying is that low-alloying alloys have coarse primary α-Mg grains with few hydrogen diffusion channels such as grain boundaries. Furthermore, in large Mg grains, the hydrogen diffusion distance is relatively long, leading to difficulties in hydrogen diffusion and thus poor kinetic performance. High-alloying alloys, on the other hand, introduce alloying elements that cause capacity loss, exhibiting an irreversible adsorption-desorption process.
[0004] Therefore, improving the hydrogen storage performance of magnesium alloys requires precise control of the types and proportions of alloying elements to address the issues of slow kinetics and unstable cycle performance. Summary of the Invention
[0005] The purpose of this invention is to solve the problems of slow kinetics and unstable cycle performance of magnesium-based hydrogen storage alloys, and to provide a high-capacity solid solution magnesium-based hydrogen storage alloy with low-temperature hydrogen absorption and its preparation method.
[0006] This invention discloses a high-capacity solid-solution magnesium-based hydrogen storage alloy with low-temperature hydrogen absorption and the chemical formula Mg. 100-x Sc x x is 3~10.
[0007] The present invention discloses a method for preparing a high-capacity solid-solution magnesium-based hydrogen storage alloy with low-temperature hydrogen absorption:
[0008] I. Based on the chemical formula Mg 100-x Sc x Weigh the raw materials, where x is 3~10;
[0009] 2. The raw materials are vacuum dried and then smelted under a protective gas at a temperature of 750~850℃. After being stirred evenly, the mixture is poured into a mold to obtain a cast alloy, thus completing the process.
[0010] The beneficial effects of this invention are:
[0011] I. This invention utilizes the addition of the rare earth element Sc to form a MgSc solid solution alloy in magnesium alloys. The solid solution effect increases the cell volume, which facilitates hydrogen atom diffusion and simultaneously improves the structural stability of the alloy during hydrogen absorption and desorption processes, maintaining good hydrogen absorption performance at low temperatures. The solid solution of Sc ensures structural stability of the alloy during repeated hydrogen absorption and desorption, reducing performance degradation caused by lattice distortion.
[0012] II. The solid-solution magnesium-based hydrogen storage alloy obtained by this invention has a uniform element distribution. During the hydrogen absorption and desorption cycle, a ScH2 nanocatalytic phase is formed in situ, which plays a positive role in the dissociation of hydrogen molecules and the diffusion of hydrogen atoms, significantly improving the hydrogen absorption and desorption kinetics. Because the Sc element is uniformly distributed in the alloy, the catalytic phase is also uniformly precipitated, avoiding local performance degradation.
[0013] Third, the solid-solution magnesium-based hydrogen storage alloy obtained by this invention effectively improves the structural stability and cycle performance of the magnesium-based hydrogen storage alloy through the solid-solution effect of Sc, the formation of in-situ SCH2 nanocatalytic phase, uniform microstructure control, and optimized preparation process.
[0014] Fourth, this invention uses resistance melting technology, which can precisely control the amount of alloying elements added, and achieve precise control of the composition of magnesium-based hydrogen storage alloy. It has the characteristics of short preparation process, high melting efficiency and low production cost, and is suitable for large-scale industrial production. Attached Figure Description
[0015] Figure 1 The X-ray diffraction patterns are those in Examples 1-3;
[0016] Figure 2 This is a microstructure diagram of Example 1;
[0017] Figure 3 This is a microstructure diagram of Example 2;
[0018] Figure 4 The hydrogen absorption and desorption test curves for Example 1;
[0019] Figure 5 The hydrogen absorption and desorption test curves for Example 2;
[0020] Figure 6 The hydrogen absorption and desorption test curves for Example 3;
[0021] Figure 7 The low-temperature hydrogen absorption test curves are those of Examples 1-3;
[0022] Figure 8 The figure shows the cycle performance curve for Example 1. Detailed Implementation
[0023] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any combination of the specific embodiments.
[0024] Specific Implementation Method 1: This implementation method describes a high-capacity solid-solution magnesium-based hydrogen storage alloy with the chemical formula Mg. 100-x Sc x x is 3~10
[0025] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the magnesium-based hydrogen storage alloy is composed of 97% Mg and 3% Sc by atomic percentage, and its chemical formula is Mg 97 Sc3. Everything else is the same as in Specific Implementation Method 1.
[0026] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the magnesium-based hydrogen storage alloy is composed of 96% Mg and 4% Sc by atomic percentage, and its chemical formula is Mg 96 Sc4. Other aspects are the same as in specific implementation method one or two.
[0027] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the magnesium-based hydrogen storage alloy is composed of 94% Mg and 6% Sc by atomic percentage, and its chemical formula is Mg 94 Sc6. Other aspects are the same as in any of the specific embodiments one to three.
[0028] Specific Implementation Method 5: The preparation method of a high-capacity solid solution magnesium-based hydrogen storage alloy with low-temperature hydrogen absorption in this implementation method is as follows:
[0029] I. Based on the chemical formula Mg 100-x Sc x Weigh the raw materials, where x is 3~10;
[0030] 2. The raw materials are vacuum dried and then smelted under a protective gas at a temperature of 750~850℃. After being stirred evenly, the mixture is poured into a mold to obtain a cast alloy, thus completing the process.
[0031] In this embodiment, the raw materials are placed in a crucible, and then the crucible is placed in a vacuum drying oven for vacuum drying; the crucible material is one or more of corundum, graphite, quartz, silicon carbide, and boron nitride; the vacuum drying temperature is 50~80℃, and the drying time is 12~15h.
[0032] Specific Implementation Method Six: This implementation method differs from Specific Implementation Method Five in that the raw materials in step one are pure Mg ingots with a purity higher than 99.9 wt.% and Mg-20 wt.%Sc master alloy. Everything else is the same as in Specific Implementation Method Five.
[0033] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Method Five or Six in that: in step two, a vacuum drying oven is used for vacuum drying at a temperature of 50~80℃ for 12~15 hours. Everything else is the same as in Specific Implementation Method Five or Six.
[0034] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods Five to Seven in that the protective gas mentioned in step two is a mixture of CO2 / SF6 with a volume ratio of 40:1. Everything else is the same as in Specific Implementation Methods Five to Seven.
[0035] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods Five to Eight in that the smelting process in step two is as follows: After completely melting the pure Mg ingot at 750°C, the Mg-20 wt.%Sc master alloy is fed into the molten Mg using a stainless steel spatula, and the temperature is raised to 850°C; stirring is performed every 20 minutes for 10-40 seconds, for a total of 4 times. Everything else is the same as in Specific Implementation Methods Five to Eight.
[0036] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods Five to Nine in that the mold is a preheated cast iron mold at 150°C. Everything else is the same as in Specific Implementation Methods Five to Nine.
[0037] The beneficial effects of the present invention are verified using the following embodiments:
[0038] Example 1: A high-capacity solid-solution magnesium-based hydrogen storage alloy with low-temperature hydrogen absorption has the chemical formula Mg 97 Sc3. The specific steps of its preparation method are as follows:
[0039] (1) Based on the chemical formula Mg 97 Sc3 is a mixture of pure Mg ingots and Mg-20 wt.%Sc master alloy in a certain proportion, with a total weight of 65g and the mass of each element accurate to three decimal places.
[0040] (2) Place the intermediate alloy and pure Mg ingot into a crucible and vacuum dry in a vacuum drying oven at a temperature of 50-80°C for 12-15 hours.
[0041] (3) After vacuum drying, the alloy is smelted in a resistance furnace under a protective gas. After the pure Mg ingot is completely melted at 750°C, the Mg-20 wt.%Sc intermediate alloy is fed into the molten Mg through a stainless steel spatula and the temperature is raised to 850°C. Stir once every 20 minutes for 10~40 seconds, and stir 4 times. The smelting temperature is 750-850°C. After forming a molten state, stir thoroughly. Then cast into a preheated 150°C cast iron mold to obtain the as-cast alloy, which is complete.
[0042] X-ray diffraction experiments were performed on this embodiment, such as... Figure 1 As shown, all diffraction peaks originate from the Mg phase, and no related peaks for Sc were detected, indicating that this alloy has a single-phase solid solution structure. Scanning electron microscopy (SEM) results are as follows... Figure 2 As shown, Sc is dissolved in Mg dendrites, and further compositional segregation occurs due to crystallization imbalance. Figure 4 The figure shows the hydrogen absorption and desorption curves of the activated cast alloy at 300℃. Under 3.0MPa conditions, it absorbs 5.9 wt.% hydrogen within 30 minutes and can completely dehydrogenate under normal pressure. Figure 7 The hydrogen absorption curve is shown at 125℃ and 3.0MPa, with an absorption amount greater than 2.0 wt.% within 2 hours. Figure 8 The curve shows the cycling performance. After 30 hydrogen absorption and desorption cycles, the capacity retention is ~98%, demonstrating excellent hydrogen absorption and desorption cycle stability of the alloy.
[0043] Example 2: A high-capacity solid-solution magnesium-based hydrogen storage alloy with low-temperature hydrogen absorption has the chemical formula Mg. 96 Sc4. The specific steps of its preparation method are as follows:
[0044] (1) Based on the chemical formula Mg 96 Sc4 is made by blending pure Mg ingots and Mg-20 wt.%Sc master alloy in a certain proportion, with a total weight of 65g and the mass of each element accurate to three decimal places.
[0045] (2) Place the intermediate alloy and pure Mg ingot into a crucible and vacuum dry in a vacuum drying oven at a temperature of 50-80°C for 12-15 hours.
[0046] (3) After vacuum drying, the alloy is smelted in a resistance furnace under a protective gas. After the pure Mg ingot is completely melted at 750°C, the Mg-20 wt.%Sc intermediate alloy is fed into the molten Mg through a stainless steel spatula and the temperature is raised to 850°C. Stir once every 20 minutes for 10~40 seconds, and stir 4 times. The smelting temperature is 750-850°C. After forming a molten state, stir thoroughly. Then cast into a preheated 150°C cast iron mold to obtain the as-cast alloy, which is complete.
[0047] X-ray diffraction experiments were performed on this embodiment, such as... Figure 1 As shown, all diffraction peaks originate from the Mg phase, and no related peaks for Sc were detected, indicating that this alloy has a single-phase solid solution structure. Scanning electron microscopy (SEM) results are as follows... Figure 3 As shown, Sc is dissolved in Mg dendrites, and further compositional segregation occurs due to crystallization imbalance. Figure 5 The figure shows the hydrogen absorption and desorption curves of the activated cast alloy at 300℃. Under 3.0MPa conditions, it absorbs 6.25 wt.% hydrogen within 30 minutes and can completely dehydrogenate under normal pressure. Figure 7 The hydrogen absorption curve is shown at 125℃ and 3.0MPa, with an absorption amount greater than 2.0 wt.% within 2 hours.
[0048] Example 3: A high-capacity solid-solution magnesium-based hydrogen storage alloy with low-temperature hydrogen absorption has the chemical formula Mg. 94 Sc6. The specific steps of its preparation method are as follows:
[0049] (1) Based on the chemical formula Mg 94 Sc6 is made by blending pure Mg ingots and Mg-20 wt.%Sc master alloy in a certain proportion, with a total weight of 65g and the mass of each element accurate to three decimal places.
[0050] (2) Place the intermediate alloy and pure Mg ingot into a crucible and vacuum dry in a vacuum drying oven at a temperature of 50-80°C for 12-15 hours.
[0051] (3) After vacuum drying, the alloy is smelted in a resistance furnace under a protective gas. After the pure Mg ingot is completely melted at 750°C, the Mg-20 wt.%Sc intermediate alloy is fed into the molten Mg through a stainless steel spatula and the temperature is raised to 850°C. Stir once every 20 minutes for 10~40 seconds, and stir 4 times. The smelting temperature is 750-850°C. After forming a molten state, stir thoroughly. Then cast into a preheated 150°C cast iron mold to obtain the as-cast alloy, which is complete.
[0052] X-ray diffraction experiments were performed on this embodiment, such as... Figure 1 As shown, all diffraction peaks originate from the Mg phase, and no Sc-related peaks were detected, indicating that this alloy has a single-phase solid solution structure. Figure 6 The figure shows the hydrogen absorption and desorption curves of the activated cast alloy at 300℃. Under 3.0MPa conditions, it absorbs 5.7 wt.% hydrogen within 30 minutes and can completely dehydrogenate under normal pressure. Figure 7 The hydrogen absorption curve is shown at 125℃ and 3.0MPa, with an absorption amount greater than 2.0 wt.% within 2 hours.
Claims
1. A high-capacity solid-solution magnesium-based hydrogen storage alloy for low-temperature hydrogen absorption, characterized in that... The chemical formula of the magnesium-based hydrogen storage alloy is Mg 100-x Sc x x is 3~10.
2. The high-capacity solid-solution magnesium-based hydrogen storage alloy for low-temperature hydrogen absorption according to claim 1, characterized in that, The magnesium-based hydrogen storage alloy is composed of 97% Mg and 3% Sc by atomic percentage, and has the chemical formula Mg. 97 Sc3.
3. The high-capacity solid-solution magnesium-based hydrogen storage alloy for low-temperature hydrogen absorption according to claim 1, characterized in that, The magnesium-based hydrogen storage alloy is composed of 96% Mg and 4% Sc by atomic percentage, and has the chemical formula Mg. 96 Sc4.
4. The high-capacity solid-solution magnesium-based hydrogen storage alloy for low-temperature hydrogen absorption according to claim 1, characterized in that, The magnesium-based hydrogen storage alloy is composed of 94% Mg and 6% Sc by atomic percentage, and has the chemical formula Mg. 94 Sc6.
5. The method for preparing a high-capacity solid-solution magnesium-based hydrogen storage alloy with low-temperature hydrogen absorption as described in claim 1, characterized in that, The preparation method is as follows: I. Based on the chemical formula Mg 100-x Sc x Weigh the raw materials, where x is 3~10; 2. The raw materials are vacuum dried and then smelted under a protective gas at a temperature of 750~850℃. After being stirred evenly, the mixture is poured into a mold to obtain a cast alloy, thus completing the process.
6. The method for preparing a high-capacity solid-solution magnesium-based hydrogen storage alloy with low-temperature hydrogen absorption according to claim 5, characterized in that, In step one, the raw materials are pure Mg ingots with a purity of higher than 99.9 wt.% and Mg-20 wt.%Sc master alloy.
7. The method for preparing a high-capacity solid-solution magnesium-based hydrogen storage alloy with low-temperature hydrogen absorption according to claim 5, characterized in that, In step two, a vacuum drying oven is used for vacuum drying at a temperature of 50-80℃ for 12-15 hours.
8. The method for preparing a high-capacity solid-solution magnesium-based hydrogen storage alloy with low-temperature hydrogen absorption according to claim 5, characterized in that, The protective gas mentioned in step two is a mixture of CO2 and SF6 with a volume ratio of 40:
1.
9. The method for preparing a high-capacity solid-solution magnesium-based hydrogen storage alloy with low-temperature hydrogen absorption according to claim 5, characterized in that, The smelting process in step two is as follows: after the pure Mg ingot is completely melted at 750℃, the Mg-20 wt.%Sc master alloy is fed into the molten Mg through a stainless steel spatula, and the temperature is raised to 850℃; the mixture is stirred once every 20 minutes for 10~40 seconds, and stirred 4 times.
10. The method for preparing a high-capacity solid-solution magnesium-based hydrogen storage alloy with low-temperature hydrogen absorption according to claim 5, characterized in that, The mold is a cast iron mold preheated to 150℃.