Magnesium-rich hydrogen storage material capable of realizing low-temperature hydrogen desorption through multi-stage regulation and control and preparation method of magnesium-rich hydrogen storage material
Through multi-stage regulation methods, including ball milling and high-pressure hydrogenation steps, low-temperature hydrogen release Mg-Ni-Fe alloy was prepared, which solved the problem of high hydrogen release temperature of magnesium alloy hydrogen storage materials, and achieved low energy consumption and high-efficiency hydrogen storage effect , suitable for on-board and mobile devices.
Patent Information
- Application Number
- CN202411269518.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-11
- Publication Date
- 2024-12-13
AI Technical Summary
The existing magnesium alloy hydrogen storage materials have problems such as difficulty in activation, slow hydrogen absorption and release kinetics, and high hydrogen release temperature, which limits its implementation in vehicle-mounted and mobile equipment applications.
The multi-stage regulation method is adopted, including ball mill-component optimization, high-pressure hydrogenation-multiphase synergistic hydrogenation and ball mill-catalytic destabilization steps, and Mg-xwt.%Ni-15-xwt.%Fe alloy is prepared by short-term high-energy ball milling, High-pressure hydrogenation and catalyst addition promote alloying and hydrogenation and reduce the hydrogen release temperature.
It realizes hydrogen discharge at low temperature, shortens the preparation cycle, reduces energy consumption, improves the thermal stability and safety of the material, making it suitable for applications such as fuel cell vehicles and mobile power equipment.
Smart Images
Figure CN119121015A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of hydrogen storage materials, and particularly to a magnesium-rich hydrogen storage material and a preparation method thereof that realizes low-temperature hydrogen release through multi-stage regulation. Background Art
[0002] Solid-state hydrogen storage materials, especially light metal alloy materials, have become a research hotspot due to their high hydrogen storage density, good safety and easy-to-carry characteristics. Magnesium alloys are regarded as one of the most promising hydrogen storage materials because of their extremely high hydrogen storage capacity (theoretical value can reach 7.6wt%). However, pure magnesium has problems such as difficulty in activation, slow hydrogen absorption and desorption kinetics, and high hydrogen desorption temperature (usually above 300°C), which limits the implementation of related devices and thus cannot be applied to vehicles and mobile devices. In order to overcome the above difficulties, researchers are constantly exploring various strategies such as alloying, nano-sizing, and introducing catalysts to accelerate the hydrogen absorption and desorption kinetics of hydrogen storage materials and increase their hydrogen storage capacity. However, the current alloying method has a long preparation cycle, is time-consuming and labor-intensive. Although the capacity of hydrogen storage materials is high and the kinetics are improved, their desorption temperature is 300-400°C, and the energy consumption is high. The final prepared hydrogen storage material has low efficiency and is not suitable for mobile devices and vehicle applications.
[0003] However, the current mechanical ball milling method has a long preparation cycle (>24 hours), which is time-consuming and labor-intensive. Although the hydrogen storage material has a higher capacity and improved kinetics, its hydrogen desorption temperature is 300-400°C, which has high energy consumption. The final prepared hydrogen storage material has low efficiency and is not suitable for mobile equipment and vehicle-mounted applications. Summary of the invention
[0004] In order to overcome the above problems in the prior art, the purpose of the present invention is to provide a magnesium-rich hydrogen storage material and a preparation method for realizing low-temperature hydrogen desorption with multi-stage regulation. The method aims to effectively reduce the hydrogen desorption temperature, increase the hydrogen absorption and desorption rate, and ensure the hydrogen storage capacity of the material, thereby providing a new method for low-energy magnesium-based hydrogen storage materials.
[0005] In order to achieve the above object, the technical solution adopted by the present invention is:
[0006] A magnesium-rich hydrogen storage material for achieving low-temperature hydrogen release through multi-stage regulation, namely, Mg-xwt.%Ni-15-xwt.%Fe (0<x<15), wherein Mg accounts for 85wt.%, Ni powder content is 0-15wt.%, and the rest is Fe powder. The obtained alloy powder presents irregular particles, and the degree of particle refinement varies with the change of Fe powder content. The Fe powder is used as a ball milling aid, and the higher the content, the greater the particle refinement.
[0007] A method for preparing a magnesium-rich hydrogen storage material with multi-stage regulation to achieve low-temperature hydrogen release comprises the following steps:
[0008] Step 1, ball milling-composition optimization:
[0009] The powder is mixed with Mg powder accounting for 85wt.%, Ni powder content 0-15wt.%, and the rest is Fe powder, and a high-energy ball mill is used for short-time high-energy ball milling; the ball milling beads will produce strong impact and shear force on the powder, resulting in the breakage of the powder particles, thereby significantly increasing the surface area of the powder and the contact area between the powder particles, promoting the diffusion of Mg and Ni atoms at the interface, thereby accelerating alloying;
[0010] The stable Mg2Ni phase is formed, and the ball milling atmosphere is H2, which promotes the surface micro-hydrogenation to obtain the desired magnesium alloy powder;
[0011] Step 2, high pressure hydrogenation-multiphase coordinated hydrogenation:
[0012] The magnesium alloy powder obtained in step 1 is placed in a magnetic reactor. The air needs to be isolated during the whole process to prevent the sample from being oxidized, and the hydrogenated magnesium alloy powder is obtained. The magnesium alloy powder contains two hydride phases, MgH2 and Mg2NiH4. The presence of Ni helps the diffusion of hydrogen atoms in the material lattice, thereby accelerating the formation and decomposition process of the hydride.
[0013] Step 3, ball milling-catalytic destabilization:
[0014] The hydrogenated magnesium alloy powder obtained in step 2 is compounded with the catalyst TM@C (TM=Co / Ni / CoNi) by short-time ball milling in a ball mill. In the alloy system with added catalyst, the catalyst accounts for 1wt.% to 5wt.%, obtaining the composite alloy powder to obtain a low-temperature hydrogen-degrading magnesium-rich alloy hydrogen storage material.
[0015] In the step 1, the ball-to-material ratio is (10-40):1, stainless steel balls with diameters of 10 mm / 5 mm / 2.5 mm are used, the mass ratio of large balls, medium balls and small balls is (5-50):(2.5-25):(0.5-5), the ball milling time is 4-8 hours, the ball mill speed is 500-1000 r / min, and the particle size of the alloy powder after ball milling is less than 200 μm.
[0016] In the magnetic reaction kettle of step 2, the magnesium alloy powder is subjected to high pressure hydrogenation at 280-350° C. and a hydrogen pressure of 5-10 MPa for 6-12 hours.
[0017] In step 3, the ball milling atmosphere is nitrogen, the ball-to-material ratio is (10-40):1, 5 mm / 2.5 mm diameter stainless steel balls are used, the mass ratio of large balls to small balls is (1-9):1, the ball milling time is 10-60 minutes, the ball mill speed is 300-600 r / min, and the final powder particle size is <200 μm.
[0018] Alloying is achieved through step 1, multi-phase synergistic hydrogenation is achieved through step 2, and catalysis is achieved through step 3. The above multi-stage control means greatly shortens the preparation cycle. During the hydrogen absorption and desorption process, alloying promotes the thermodynamic destabilization of magnesium-based hydrogen storage, multi-phase synergistic hydrogenation promotes the kinetics of hydrogen absorption and desorption, and catalysis provides active sites, providing a low reaction path for the breaking of Mg-H bonds. Under the multi-stage control strategy, the Mg-Ni-Fe alloy system finally starts to dehydrogenate at around 180°C, and the peak dehydrogenation temperature is lower than 300°C.
[0019] Beneficial effects of the present invention
[0020] The present invention provides a simple multi-stage control method for preparing magnesium-rich hydrogen storage materials that can release hydrogen at low temperature. Through simple mechanical ball milling and control of process parameters, multi-stage optimization is achieved and a magnesium-nickel-iron ternary hydrogen storage alloy that can release hydrogen quickly at low temperature is prepared. During the preparation process, short-term high-energy ball milling is used to simultaneously achieve surface micro-hydrogenation and alloying of the three alloy powders, increase surface defects and improve the oxidation resistance of the alloy powders. A high-pressure hydrogenation step is then performed to obtain a fully hydrogenated magnesium-nickel-iron hydrogenated alloy powder. The simple ball milling method greatly reduces the smelting preparation cost and shortens the preparation cycle. The process is simple. The prepared Mg-Ni-Fe ternary alloy can release hydrogen at 290.27°C, and the peak temperature of hydrogen release is also lower than 350°C, which reduces the energy consumption of the hydrogen release process and the maintenance cost, and is conducive to promoting the research and development of solid-state hydrogen storage devices. In addition, after adding the catalyst, a variety of hydrides are formed, which synergistically achieve thermodynamic destabilization, further reducing the initial hydrogen desorption temperature of the system to 184.56°C, and the peak hydrogen desorption temperature is reduced to 220.39°C (Mg2NiH4) and 268.02°C (MgH2). The initial hydrogen desorption temperature of around 180°C means that the material can start the hydrogen desorption process under relatively mild conditions, which is very meaningful for reducing energy consumption and improving the overall efficiency of the system. The hydrogen desorption process below 300°C indicates that the material can work effectively at lower temperatures, which not only reduces operating costs, but also improves the thermal stability of the material and prolongs its service life. In addition, due to the low operating temperature, the risk of overheating is reduced and the safety of the material during use is improved. Therefore, the Mg-Ni-Fe ternary hydrogen storage material in the present invention has the potential to be used in application scenarios that are sensitive to temperature or need to operate within a wide temperature range, such as fuel cell vehicles and mobile power supply equipment.
[0021] The present invention shortens the ball milling time to less than 8 hours through mechanical ball milling in step 1, directly performs high-pressure hydrogenation on the sample in step 2, and the hydrogenation time is ≤12 hours. Finally, the preparation period of the low-temperature hydrogen-degrading magnesium-rich alloy is greatly shortened (<24 hours) through catalytic compounding (≤1 hour) in step 3, and its performance is verified through subsequent characterization test means, thereby achieving hydrogen degrading below 300°C. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 The present invention is a process flow chart for preparing Mg-Ni-Fe ternary hydrogen storage alloy by multi-stage regulation.
[0023] Figure 2 Actual picture of Mg-Ni-Fe ternary alloy after multi-level regulation optimization (a) Mg-Ni-Fe (b) Mg-Ni-Fe-Ni@C.
[0024] Figure 3 Isothermal hydrogen desorption curve of Mg-Ni-Fe after multi-stage regulation optimization (a) Mg-Ni-Fe (b) Mg-Ni-Fe-Ni@C. DETAILED DESCRIPTION
[0025] Example 1
[0026] The multi-level regulated magnesium-nickel-iron ternary alloy described in the present invention is Mg-xwt.%Ni-15-xwt.%Fe (0<x<15), wherein Mg accounts for 85wt.%, Ni powder content is 0-15wt.%, and the rest is Fe powder.
[0027] Step 1, ball milling-composition optimization:
[0028] According to the ratio of 85wt.% of Mg powder, 3wt.% of Ni powder and 12wt.% of Fe powder, a high-energy ball mill is used for short-time high-energy ball milling. The ball milling beads will produce strong impact and shear force on the powder, resulting in the crushing of the powder particles, thereby significantly increasing the surface area of the powder and the contact area between the powder particles, promoting the diffusion of Mg and Ni atoms at the interface, thereby accelerating alloying and forming a stable Mg2Ni phase. The ball milling atmosphere is H2, which can promote surface micro-hydrogenation. The ball-to-material ratio is 15:1. Stainless steel balls with diameters of 10mm / 5mm / 2.5mm are used. The mass ratio of large balls, medium balls and small balls is 25:5:1. The ball milling time is 4 hours, the ball mill speed is 1000r / min, and the alloy powder particle size after ball milling is less than 200μm, and the desired magnesium alloy powder is obtained.
[0029] Step 2, high pressure hydrogenation-multiphase coordinated hydrogenation:
[0030] The magnesium alloy powder obtained in step 1 is placed in a magnetic reactor. The air needs to be isolated during the entire process to prevent oxidation of the sample. The magnesium alloy powder is subjected to high-pressure hydrogenation at 350° C. and a hydrogen pressure of 6 MPa for 6 hours to obtain a hydrogenated magnesium alloy powder.
[0031] Step 3, ball milling-catalytic destabilization:
[0032] The magnesium hydride alloy powder obtained in step 2 is evenly divided into four parts, one of which is directly ball-milled, and the other three parts are short-time ball-milled with a homemade catalyst in a ball mill, the catalyst content is 5wt.%, the ball-milling atmosphere is nitrogen, the ball-to-material ratio is 15:1, 5mm / 2.5mm diameter stainless steel balls are used, the mass ratio of large balls to small balls is 9:1, the ball-milling time is 60 minutes, the ball mill speed is 600r / min, and the final alloy powder particle size is <200μm, and uncompounded / compounded alloy powders are obtained to obtain low-temperature hydrogen-releasing magnesium-rich alloy hydrogen storage materials.
[0033] Example 2
[0034] The multi-level regulated magnesium-nickel-iron ternary alloy described in the present invention is Mg-xwt.%Ni-15-xwt.%Fe (0<x<15), wherein Mg accounts for 85wt.%, Ni powder content is 0-15wt.%, and the rest is Fe powder.
[0035] Step 1, ball milling-composition optimization:
[0036] According to the ratio of Mg powder 85wt.%, Ni powder 10wt.% and Fe powder 5wt.%, a high-energy ball mill is used for short-time high-energy ball milling. The ball milling beads will produce strong impact and shear force on the powder, resulting in the crushing of the powder particles, thereby significantly increasing the surface area of the powder and the contact area between the powder particles, promoting the diffusion of Mg and Ni atoms at the interface, thereby accelerating alloying and forming a stable Mg2Ni phase. The ball milling atmosphere is H2, which can promote surface micro-hydrogenation. The ball-to-material ratio is 15:1. Stainless steel balls with diameters of 10mm / 5mm / 2.5mm are used. The mass ratio of large balls, medium balls and small balls is 25:5:1. The ball milling time is 4 hours, the ball mill speed is 1000r / min, and the alloy powder particle size after ball milling is less than 200μm, and the desired magnesium alloy powder is obtained.
[0037] Step 2, high pressure hydrogenation-multiphase coordinated hydrogenation:
[0038] The magnesium alloy powder obtained in step 1 is placed in a magnetic reactor. The air needs to be isolated during the entire process to prevent oxidation of the sample. The magnesium alloy powder is subjected to high-pressure hydrogenation at 350° C. and a hydrogen pressure of 6 MPa for 6 hours to obtain a hydrogenated magnesium alloy powder.
[0039] Step 3, ball milling-catalytic destabilization:
[0040] The magnesium hydride alloy powder obtained in step 2 is evenly divided into four parts, one of which is directly ball-milled, and the other three parts are short-time ball-milled with a homemade catalyst in a ball mill, the catalyst content is 5wt.%, the ball-milling atmosphere is nitrogen, the ball-to-material ratio is 15:1, 5mm / 2.5mm diameter stainless steel balls are used, the mass ratio of large balls to small balls is 9:1, the ball-milling time is 60 minutes, the ball mill speed is 600r / min, and the final alloy powder particle size is <200μm, and uncompounded / compounded alloy powders are obtained to obtain low-temperature hydrogen-releasing magnesium-rich alloy hydrogen storage materials.
[0041] Example 3
[0042] The multi-level regulated magnesium-nickel-iron ternary alloy described in the present invention is Mg-xwt.%Ni-15-xwt.%Fe (0<x<15), wherein Mg accounts for 85wt.%, Ni powder content is 0-15wt.%, and the rest is Fe powder.
[0043] Step 1, ball milling-composition optimization:
[0044] According to the ratio of Mg powder 85wt.%, Ni powder 13wt.% and Fe powder 2wt.%, a high-energy ball mill is used for short-time high-energy ball milling. The ball milling beads will produce strong impact and shear force on the powder, resulting in the crushing of the powder particles, thereby significantly increasing the surface area of the powder and the contact area between the powder particles, promoting the diffusion of Mg and Ni atoms at the interface, thereby accelerating alloying and forming a stable Mg2Ni phase. The ball milling atmosphere is H2, which can promote surface micro-hydrogenation. The ball-to-material ratio is 15:1. Stainless steel balls with diameters of 10mm / 5mm / 2.5mm are used. The mass ratio of large balls, medium balls and small balls is 25:5:1. The ball milling time is 4 hours, the ball mill speed is 1000r / min, and the alloy powder particle size after ball milling is less than 200μm, and the desired magnesium alloy powder is obtained.
[0045] Step 2, high pressure hydrogenation-multiphase coordinated hydrogenation:
[0046] The magnesium alloy powder obtained in step 1 is placed in a magnetic reactor. The air needs to be isolated during the entire process to prevent oxidation of the sample. The magnesium alloy powder is subjected to high-pressure hydrogenation at 350° C. and a hydrogen pressure of 6 MPa for 6 hours to obtain a hydrogenated magnesium alloy powder.
[0047] Step 3, ball milling-catalytic destabilization:
[0048] The magnesium hydride alloy powder obtained in step 2 is evenly divided into four parts, one of which is directly ball-milled, and the other three parts are short-time ball-milled with a homemade catalyst in a ball mill, the catalyst content is 5wt.%, the ball-milling atmosphere is nitrogen, the ball-to-material ratio is 15:1, 5mm / 2.5mm diameter stainless steel balls are used, the mass ratio of large balls to small balls is 9:1, the ball-milling time is 60 minutes, the ball mill speed is 600r / min, and the final alloy powder particle size is <200μm, and uncompounded / compounded alloy powders are obtained to obtain low-temperature hydrogen-releasing magnesium-rich alloy hydrogen storage materials.
[0049] Example 4
[0050] The multi-level regulated magnesium-nickel-iron ternary alloy described in the present invention is Mg-xwt.%Ni-15-xwt.%Fe (0<x<15), wherein Mg accounts for 85wt.%, Ni powder content is 0-15wt.%, and the rest is Fe powder.
[0051] Step 1, ball milling-composition optimization:
[0052] According to the ratio of 85wt.% of Mg powder, 3wt.% of Ni powder and 12wt.% of Fe powder, a high-energy ball mill is used for short-time high-energy ball milling. The ball milling beads will produce strong impact and shear force on the powder, resulting in the crushing of the powder particles, thereby significantly increasing the surface area of the powder and the contact area between the powder particles, promoting the diffusion of Mg and Ni atoms at the interface, thereby accelerating alloying and forming a stable Mg2Ni phase. The ball milling atmosphere is H2, which can promote surface micro-hydrogenation. The ball-to-material ratio is 15:1. Stainless steel balls with diameters of 10mm / 5mm / 2.5mm are used. The mass ratio of large balls, medium balls and small balls is 25:5:1. The ball milling time is 8 hours, the ball mill speed is 1000r / min, and the alloy powder particle size after ball milling is less than 200μm, and the desired magnesium alloy powder is obtained.
[0053] Step 2, high pressure hydrogenation-multiphase coordinated hydrogenation:
[0054] The magnesium alloy powder obtained in step 1 is placed in a magnetic reactor. The air needs to be isolated during the entire process to prevent oxidation of the sample. The magnesium alloy powder is subjected to high-pressure hydrogenation at 350° C. and a hydrogen pressure of 6 MPa for 6 hours to obtain a hydrogenated magnesium alloy powder.
[0055] Step 3, ball milling-catalytic destabilization:
[0056] The magnesium hydride alloy powder obtained in step 2 is evenly divided into four parts, one of which is directly ball-milled, and the other three parts are short-time ball-milled with a homemade catalyst in a ball mill, the catalyst content is 5wt.%, the ball-milling atmosphere is nitrogen, the ball-to-material ratio is 15:1, 5mm / 2.5mm diameter stainless steel balls are used, the mass ratio of large balls to small balls is 9:1, the ball-milling time is 60 minutes, the ball mill speed is 600r / min, and the final alloy powder particle size is <200μm, and uncompounded / compounded alloy powders are obtained to obtain low-temperature hydrogen-releasing magnesium-rich alloy hydrogen storage materials.
[0057] Example 5
[0058] The multi-level regulated magnesium-nickel-iron ternary alloy described in the present invention is Mg-xwt.%Ni-15-xwt.%Fe (0<x<15), wherein Mg accounts for 85wt.%, Ni powder content is 0-15wt.%, and the rest is Fe powder.
[0059] Step 1, ball milling-composition optimization:
[0060] According to the ratio of 85wt.% of Mg powder, 3wt.% of Ni powder and 12wt.% of Fe powder, a high-energy ball mill is used for short-time high-energy ball milling. The ball milling beads will produce strong impact and shear force on the powder, resulting in the crushing of the powder particles, thereby significantly increasing the surface area of the powder and the contact area between the powder particles, promoting the diffusion of Mg and Ni atoms at the interface, thereby accelerating alloying and forming a stable Mg2Ni phase. The ball milling atmosphere is H2, which can promote surface micro-hydrogenation. The ball-to-material ratio is 15:1. Stainless steel balls with diameters of 10mm / 5mm / 2.5mm are used. The mass ratio of large balls, medium balls and small balls is 25:5:1. The ball milling time is 4 hours, the ball mill speed is 1000r / min, and the alloy powder particle size after ball milling is less than 200μm, and the desired magnesium alloy powder is obtained.
[0061] Step 2, high pressure hydrogenation-multiphase coordinated hydrogenation:
[0062] The magnesium alloy powder obtained in step 1 is placed in a magnetic reactor. The air needs to be isolated during the entire process to prevent oxidation of the sample. The magnesium alloy powder is subjected to high-pressure hydrogenation at 280° C. and a hydrogen pressure of 6 MPa for 6 hours to obtain a hydrogenated magnesium alloy powder.
[0063] Step 3, ball milling-catalytic destabilization:
[0064] The magnesium hydride alloy powder obtained in step 2 is evenly divided into four parts, one of which is directly ball-milled, and the other three parts are short-time ball-milled with a homemade catalyst in a ball mill, the catalyst content is 5wt.%, the ball-milling atmosphere is nitrogen, the ball-to-material ratio is 15:1, 5mm / 2.5mm diameter stainless steel balls are used, the mass ratio of large balls to small balls is 9:1, the ball-milling time is 60 minutes, the ball mill speed is 600r / min, and the final alloy powder particle size is <200μm, and uncompounded / compounded alloy powders are obtained to obtain low-temperature hydrogen-releasing magnesium-rich alloy hydrogen storage materials.
[0065] Example 6
[0066] The multi-level regulated magnesium-nickel-iron ternary alloy described in the present invention is Mg-xwt.%Ni-15-xwt.%Fe (0<x<15), wherein Mg accounts for 85wt.%, Ni powder content is 0-15wt.%, and the rest is Fe powder.
[0067] Step 1, ball milling-composition optimization:
[0068] According to the ratio of 85wt.% of Mg powder, 3wt.% of Ni powder and 12wt.% of Fe powder, a high-energy ball mill is used for short-time high-energy ball milling. The ball milling beads will produce strong impact and shear force on the powder, resulting in the crushing of the powder particles, thereby significantly increasing the surface area of the powder and the contact area between the powder particles, promoting the diffusion of Mg and Ni atoms at the interface, thereby accelerating alloying and forming a stable Mg2Ni phase. The ball milling atmosphere is H2, which can promote surface micro-hydrogenation. The ball-to-material ratio is 15:1. Stainless steel balls with diameters of 10mm / 5mm / 2.5mm are used. The mass ratio of large balls, medium balls and small balls is 25:5:1. The ball milling time is 4 hours, the ball mill speed is 1000r / min, and the alloy powder particle size after ball milling is less than 200μm, and the desired magnesium alloy powder is obtained.
[0069] Step 2, high pressure hydrogenation-multiphase coordinated hydrogenation:
[0070] The magnesium alloy powder obtained in step 1 is placed in a magnetic reactor. The air needs to be isolated during the entire process to prevent the sample from being oxidized. The magnesium alloy powder is subjected to high-pressure hydrogenation at 350° C. and a hydrogen pressure of 6 MPa for 12 hours to obtain a hydrogenated magnesium alloy powder.
[0071] Step 3, ball milling-catalytic destabilization:
[0072] The magnesium hydride alloy powder obtained in step 2 is evenly divided into four parts, one of which is directly ball-milled, and the other three parts are short-time ball-milled with a homemade catalyst in a ball mill, the catalyst content is 5wt.%, the ball-milling atmosphere is nitrogen, the ball-to-material ratio is 15:1, 5mm / 2.5mm diameter stainless steel balls are used, the mass ratio of large balls to small balls is 9:1, the ball-milling time is 60 minutes, the ball mill speed is 600r / min, and the final alloy powder particle size is <200μm, and uncompounded / compounded alloy powders are obtained to obtain low-temperature hydrogen-releasing magnesium-rich alloy hydrogen storage materials.
[0073] Example 7
[0074] The multi-level regulated magnesium-nickel-iron ternary alloy described in the present invention is Mg-xwt.%Ni-15-xwt.%Fe (0<x<15), wherein Mg accounts for 85wt.%, Ni powder content is 0-15wt.%, and the rest is Fe powder.
[0075] Step 1, ball milling-composition optimization:
[0076] According to the ratio of Mg powder 85wt.%, Ni powder 10wt.% and Fe powder 5wt.%, a high-energy ball mill is used for short-time high-energy ball milling. The ball milling beads will produce strong impact and shear force on the powder, resulting in the crushing of the powder particles, thereby significantly increasing the surface area of the powder and the contact area between the powder particles, promoting the diffusion of Mg and Ni atoms at the interface, thereby accelerating alloying and forming a stable Mg2Ni phase. The ball milling atmosphere is H2, which can promote surface micro-hydrogenation. The ball-to-material ratio is 15:1. Stainless steel balls with diameters of 10mm / 5mm / 2.5mm are used. The mass ratio of large balls, medium balls and small balls is 25:5:1. The ball milling time is 4 hours, the ball mill speed is 1000r / min, and the alloy powder particle size after ball milling is less than 200μm, and the desired magnesium alloy powder is obtained.
[0077] Step 2, high pressure hydrogenation-multiphase coordinated hydrogenation:
[0078] The magnesium alloy powder obtained in step 1 is placed in a magnetic reactor. The air needs to be isolated during the entire process to prevent the sample from being oxidized. The magnesium alloy powder is subjected to high-pressure hydrogenation at 350° C. and a hydrogen pressure of 6 MPa for 12 hours to obtain a hydrogenated magnesium alloy powder.
[0079] Step 3, ball milling-catalytic destabilization:
[0080] The magnesium hydride alloy powder obtained in step 2 is evenly divided into four parts, one of which is directly ball-milled, and the other three parts are short-time ball-milled with a homemade catalyst in a ball mill, the catalyst content is 5wt.%, the ball-milling atmosphere is nitrogen, the ball-to-material ratio is 15:1, 5mm / 2.5mm diameter stainless steel balls are used, the mass ratio of large balls to small balls is 9:1, the ball-milling time is 60 minutes, the ball mill speed is 600r / min, and the final alloy powder particle size is <200μm, and uncompounded / compounded alloy powders are obtained to obtain low-temperature hydrogen-releasing magnesium-rich alloy hydrogen storage materials.
[0081] Example 8
[0082] The multi-level regulated magnesium-nickel-iron ternary alloy described in the present invention is Mg-xwt.%Ni-15-xwt.%Fe (0<x<15), wherein Mg accounts for 85wt.%, Ni powder content is 0-15wt.%, and the rest is Fe powder.
[0083] Step 1, ball milling-composition optimization:
[0084] According to the ratio of Mg powder 85wt.%, Ni powder 10wt.% and Fe powder 5wt.%, a high-energy ball mill is used for short-time high-energy ball milling. The ball milling beads will produce strong impact and shear force on the powder, resulting in the crushing of the powder particles, thereby significantly increasing the surface area of the powder and the contact area between the powder particles, promoting the diffusion of Mg and Ni atoms at the interface, thereby accelerating alloying and forming a stable Mg2Ni phase. The ball milling atmosphere is H2, which can promote surface micro-hydrogenation. The ball-to-material ratio is 15:1. Stainless steel balls with diameters of 10mm / 5mm / 2.5mm are used. The mass ratio of large balls, medium balls and small balls is 25:5:1. The ball milling time is 4 hours, the ball mill speed is 1000r / min, and the alloy powder particle size after ball milling is less than 200μm, and the desired magnesium alloy powder is obtained.
[0085] Step 2, high pressure hydrogenation-multiphase coordinated hydrogenation:
[0086] The magnesium alloy powder obtained in step 1 is placed in a magnetic reactor. The air needs to be isolated during the entire process to prevent oxidation of the sample. The magnesium alloy powder is subjected to high-pressure hydrogenation at 280° C. and a hydrogen pressure of 6 MPa for 12 hours to obtain a hydrogenated magnesium alloy powder.
[0087] Step 3, ball milling-catalytic destabilization:
[0088] The magnesium hydride alloy powder obtained in step 2 is evenly divided into four parts, one of which is directly ball-milled, and the other three parts are short-time ball-milled with a homemade catalyst in a ball mill, the catalyst content is 5wt.%, the ball-milling atmosphere is nitrogen, the ball-to-material ratio is 15:1, 5mm / 2.5mm diameter stainless steel balls are used, the mass ratio of large balls to small balls is 9:1, the ball-milling time is 60 minutes, the ball mill speed is 600r / min, and the final alloy powder particle size is <200μm, and uncompounded / compounded alloy powders are obtained to obtain low-temperature hydrogen-releasing magnesium-rich alloy hydrogen storage materials.
[0089] Through different alloy addition contents, different ball milling parameters, and different high-pressure hydrogenation parameters, multi-stage regulation and optimization of magnesium-nickel-iron ternary hydrogen storage alloys are achieved, and magnesium-based hydrogen storage alloys with different alloying degrees, different hydrogenation degrees, and different particle sizes are selected. These alloys have the advantages of low energy barriers and low-temperature hydrogen desorption under the same hydrogen desorption conditions (argon atmosphere, the same heating rate), and are expected to achieve low-energy hydrogen storage. The present invention prepares magnesium-nickel-iron ternary alloys through multi-stage regulation, and simultaneously achieves surface micro-hydrogenation and alloying, improves the material's antioxidant properties, and promotes multi-phase synergistic hydrogenation, significantly improving the energy consumption of the hydrogen desorption process, while also improving the safety of the material's use. The technology of the present invention is expected to be applied to the hydrogen storage process of future mobile devices, achieving low-energy rapid hydrogen absorption and desorption, and promoting the research and development of solid-state hydrogen storage devices.
[0090] Figure 1 This is a process flow chart for preparing magnesium-nickel-iron hydrogen storage alloy by multi-stage regulation of the present invention. As can be seen from the flow chart, the alloy prepared by batching and ball milling in a hydrogen atmosphere achieves alloying and surface hydrogenation; the sample is further completely hydrogenated by high-pressure hydrogenation to prepare a magnesium-nickel-iron ternary alloy with a variety of hydrides; and a surface catalytic alloy is prepared by simple short-time mechanical ball milling. Due to different compositions, different ball milling times and different hydrogenation parameters, magnesium-nickel-iron ternary hydrogen storage alloys with different particle sizes, different hydrogenation degrees and different surface catalytic active sites can be obtained. It exhibits different hydrogen release properties. Through regulation at various levels, the hydrogen storage alloy can achieve low-temperature, low-energy hydrogen release, and is easy to promote the application of solid-state hydrogen storage.
[0091] Figure 2 The SEM image of the final magnesium-nickel-iron ternary hydrogen storage alloy obtained after multi-level regulation. From the SEM image without adding catalyst in Figure (a), it can be seen that after the composition optimization process, the alloy powder has alloyed and secondary agglomeration. After high-pressure hydrogenation and mechanical ball milling, some particles are broken. There are many Fe particles attached to the surface of the alloy, providing active sites to promote the hydrogen release process. After composite ball milling with the catalyst, the particle size is further refined, such as Figure 2As shown in (b), the introduction of Ni@C provides Ni to promote the multiphase synergistic hydrogenation in the repeated hydrogen absorption and desorption process to reduce the dehydrogenation temperature. On the other hand, it provides active sites, reducing the reaction energy barrier required for the breaking of the Mg-H bond, and ultimately achieving low-temperature dehydrogenation.
[0092] The surface contact area is increased, and the broken catalyst has a surface catalytic effect on the alloy, reducing the reaction energy barrier and promoting low-temperature hydrogen absorption and desorption.
[0093] Figure 3 The DSC curves of hydrogen release of magnesium-nickel-iron alloy without adding catalyst and with adding catalyst after multi-stage regulation of the present invention. Figure 3 (a) It can be seen that the initial dehydrogenation temperature of the alloy without adding a catalyst is 290.27°C. There is only one dehydrogenation peak in the curve corresponding to MgH2, and its dehydrogenation temperature is as low as 316.51°C, indicating that the magnesium-nickel-iron alloy powder after multi-level regulation has been improved in composition and structure. The reduction of the dehydrogenation temperature of the system is of great significance to the development of low-temperature hydrogen storage devices. Figure 3 In (b), the initial dehydrogenation temperature of the magnesium-nickel-iron alloy with the addition of the catalyst is further reduced to 184.56°C, and two dehydrogenation peaks appear on the curve, corresponding to Mg2NiH4 (220.39°C) and MgH2 (268.02°C), respectively. This indicates that the addition of the catalyst promotes the absorption of hydrogen in the intermediate phase of the alloy, and the various hydrides formed play a thermodynamic destabilizing role in the hydrogen absorption process, promoting the system to dehydrogenate at low temperature, thus achieving a low-energy dehydrogenation process below 300°C.
Claims
1. A magnesium-rich hydrogen storage material with multi-level regulation to achieve low-temperature hydrogen release, characterized in that: That is, Mg-xwt.%Ni-15-xwt.%Fe (0<x<15), wherein Mg accounts for 85wt.%, Ni powder content is 0~15wt.%, and the rest is Fe powder. The obtained alloy powder presents irregular granular shape. With the change of Fe powder content, the degree of particle refinement varies. Among them, Fe powder is used as a ball milling aid. The higher the content of Fe powder, the greater the degree of particle refinement.
2. The method for preparing a magnesium-rich hydrogen storage material with multi-stage control to achieve low-temperature hydrogen release according to claim 1, characterized in that: The following steps are involved: Step 1, ball milling-composition optimization: The proportion is 85wt.% of Mg powder, 0-15wt.% of Ni powder, and the rest is Fe powder, and a high-energy ball mill is used for short-time high-energy ball milling; The stable Mg2Ni phase is formed, and the ball milling atmosphere is H2, which promotes the surface micro-hydrogenation to obtain the desired magnesium alloy powder; Step 2, high pressure hydrogenation-multiphase coordinated hydrogenation: The magnesium alloy powder obtained in step 1 is placed in a magnetic reaction kettle. The air needs to be isolated during the whole process to prevent the sample from being oxidized, and a hydrogenated magnesium alloy powder is obtained. The magnesium alloy powder contains two hydride phases, MgH2 and Mg2NiH4; Step 3, ball milling-catalytic destabilization: The hydrogenated magnesium alloy powder obtained in step 2 is compounded with the catalyst TM@C (TM=Co / Ni / CoNi) by short-time ball milling in a ball mill. In the alloy system with added catalyst, the catalyst accounts for 1wt.% to 5wt.%, obtaining the composite alloy powder to obtain a low-temperature hydrogen-degrading magnesium-rich alloy hydrogen storage material.
3. The method for preparing a magnesium-rich hydrogen storage material with multi-stage control to achieve low-temperature hydrogen release according to claim 2, characterized in that: In the step 1, the ball-to-material ratio is (10-40):1, stainless steel balls with diameters of 10 mm / 5 mm / 2.5 mm are used, the mass ratio of large balls, medium balls and small balls is (5-50):(2.5-25):(0.5-5), the ball milling time is 4-8 hours, the ball mill speed is 500-1000 r / min, and the particle size of the alloy powder after ball milling is less than 200 μm.
4. The method for preparing a magnesium-rich hydrogen storage material with multi-stage control to achieve low-temperature hydrogen release according to claim 2, characterized in that: In the magnetic reaction kettle of step 2, the magnesium alloy powder is subjected to high pressure hydrogenation at 280-350° C. and a hydrogen pressure of 5-10 MPa for 6-12 hours.
5. The method for preparing a magnesium-rich hydrogen storage material with multi-stage control to achieve low-temperature hydrogen release according to claim 2, characterized in that: In step 3, the ball milling atmosphere is nitrogen, the ball-to-material ratio is (10-40):1, 5 mm / 2.5 mm diameter stainless steel balls are used, the mass ratio of large balls to small balls is (1-9):1, the ball milling time is 10-60 minutes, the ball mill speed is 300-600 r / min, and the final powder particle size is <200 μm.