An easily-activated hydrogen storage alloy and a method for preparing the same

Abstract

The application discloses an easy-activation hydrogen storage alloy and a preparation method thereof, and belongs to the technical field of hydrogen storage alloys. The application forms a quaternary hydrogen storage alloy with a chemical formula of Ti x V 40 Mn y Fe z by using cheap and easily-obtained Ti, Mn and Fe elements to partially replace V, wherein x, y and z respectively represent the atomic percentage of Ti, Mn and Fe, 30<=x<=40, 2<=y<=22, 3<=z<=18, and x+y+z=60. The preparation method of the hydrogen storage alloy is to melt 3-5 times under the protection of argon gas by using a vacuum non-consumable arc furnace. The application not only effectively reduces the preparation cost of the hydrogen storage alloy, but also has a simple preparation method, solves the problem of difficult activation of vanadium-based hydrogen storage alloys, and has a wide practical prospect in hydrogen gas purification and hydrogen fuel cells.

Description

TECHNICAL FIELD

[0001] The present application relates to an easily activated hydrogen storage alloy and a preparation method thereof, and belongs to the technical field of hydrogen storage alloys. BACKGROUND

[0002] In the search for alternative energy systems dominated by fossil fuels, hydrogen energy has received widespread attention due to its high energy density, green and pollution-free advantages. Hydrogen energy is one of the important carriers of recognized energy transformation development, and has a positive supporting role in achieving the goal of carbon peak and carbon neutral. The use of hydrogen energy includes three key links, namely hydrogen production, hydrogen storage and transportation, and hydrogen application. Among them, hydrogen storage and transportation is the key to building a hydrogen energy society. Vanadium-based solid solution hydrogen storage alloys in solid-state hydrogen storage technology have strong appeal to researchers in establishing scientific and technological goals. The main reasons for this appeal include high theoretical hydrogen storage capacity, reversible hydrogen absorption and desorption at room temperature and pressure, and good kinetic properties.

[0003] However, vanadium-based solid solution hydrogen storage alloys are difficult to activate, and usually require multiple hydrogen absorption and desorption cycles at high temperature and high pressure to be fully activated, which increases the difficulty of application of vanadium-based hydrogen storage alloys. In addition, high-purity metallic vanadium is expensive and not conducive to large-scale production. Currently, researchers widely use modification strategies such as element substitution or doping, component optimization, etc. to solve the above problems, for example, using metal elements Ti, Cr, Mn, Fe, Ni, etc. to partially replace pure V to form binary Ti-V-based, ternary Ti-V-Mn, Ti-V-Cr, Ti-V-Fe and Ti-V-Ni, and quaternary Ti-V-Cr-Fe, Ti-V-Cr-Ni hydrogen storage alloys, etc. Not only does it reduce the cost, but also improves the hydrogen storage performance. For example, CN114715844A discloses a vanadium-based environmentally friendly hydrogen storage material and a preparation method thereof. The raw materials of the hydrogen storage material are as follows in mass percentage: Mo 4-7%, Ni 3-6%, Ce 0.5-4%, B 2-5%, V 80-90%; the mass ratio of Ni to B is (1-1.5):1; the mass of Mo and Ce is 5-10%. The hydrogen storage material can absorb up to 5.2% of hydrogen at room temperature, but the activation conditions are harsh, and it needs to be activated completely after 3-4 times of hydrogen absorption and desorption at 673K under vacuum and 8MPa hydrogen charging. CN113502424A discloses a low-temperature activated vanadium-based hydrogen storage alloy, a preparation method and application thereof. The elemental composition of the alloy is Ti a Cr b V c RE x; wherein RE comprises one or a combination of at least two of La, Ce, or Y, a = 0.025-0.225, b = 0.075-0.675, c = 0.1-0.9, and a+b+c = 1, x = 0.01-0.1. This alloy can be directly activated at room temperature without high temperature and high pressure, however, too high V content leads to increased cost, which is not conducive to large-scale application. Since vanadium-iron concentrate in nature only needs to be simply hot reduced with silicon iron or aluminum powder to obtain cheap vanadium-iron alloy, domestic and foreign research units use vanadium-iron alloy instead of pure vanadium as a vanadium source, and seize the commanding point of intellectual property rights of vanadium-iron type solid solution hydrogen storage alloy. CN101624674A discloses a solid solution hydrogen storage alloy using low-cost vanadium-iron alloy as raw material, and the chemical formula of the alloy is Ti x -Cr y -V z -Fe m -Ce w , wherein x+y+z+m = 100, 0.8≤x / y≤1.1, 35≤(z+m)≤55, 5.0≤z / m, 0.6≤w≤2.0. It should be noted that the impurity elements such as Si, Al, C, Cu in vanadium-iron alloy have a complex influence mechanism on the hydrogen storage performance of the alloy, which may have an adverse effect. CN115612903A discloses a vanadium-based hydrogen storage alloy prepared by using high-vanadium iron alloy, and the chemical formula of the hydrogen storage alloy is V x Ti y Fe z M 100-x-y-z , wherein x, y, and z respectively represent the atomic numbers of V, Ti, and Fe, x has a value range of 60-85, y has a value range of 10-20, z has a value range of 0-6, M is one or several of Cr, Mn, Al, and RE, and RE is a rare earth metal. The vanadium content in the alloy is high, but the use of cheap V2O5 as a vanadium source reduces the cost to a certain extent, however, the activation condition is repeated hydrogen absorption and desorption at 400°C under high temperature and high pressure, which is not conducive to large-scale industrial application.

[0004] In view of the difficulty in balancing and optimizing a single index of vanadium-based solid solution hydrogen storage alloy, it is still unclear whether the balanced and optimized index has an insurmountable technical barrier. To date, there is no vanadium-based solid solution hydrogen storage alloy industrial product made of cheap industrial vanadium-iron alloy. Therefore, at least in the face of the reality that the high pursuit of the scientific and technological goal has failed, reducing the amount of high-priced elemental vanadium during the synthesis of vanadium-based solid solution hydrogen storage alloy to reduce the cost of the alloy is one of the practical technical routes. SUMMARY

[0005] The present application aims at the above technical problems existing in the prior art vanadium-based solid solution hydrogen storage alloy, and provides an easy-activated hydrogen storage alloy and a preparation method thereof, wherein Ti, Mn and Fe which are cheap and easy to obtain are used to replace V partially and the component ratio is optimized to develop a Ti-V-Mn-Fe hydrogen storage alloy with low production cost, fast activation performance, good kinetic characteristics, simple preparation process and easy batch production.

[0006] The technical scheme of the present application is as follows:

[0007] One of the objects of the present application is to provide an easy-activated hydrogen storage alloy, which has a chemical formula of Ti x V 40 Mn y Fe z , wherein x, y and z respectively represent the atomic percentage of Ti, Mn and Fe, 30≤x≤40, 2≤y≤22 and 3≤z≤18, and x+y+z=60.

[0008] Further limitation, the hydrogen storage alloy has a chemical formula of Ti 30 V 40 Mn 18 Fe 12 , Ti 35 V 40 Mn 22 Fe3 or Ti 40 V 40 Mn2Fe 18 .

[0009] Further limitation, the hydrogen storage alloy comprises a BCC phase and a C14 type Laves phase.

[0010] Further limitation, the hydrogen storage alloy is prepared from elemental titanium, vanadium, manganese and iron with a purity higher than 99.5wt.%.

[0011] The second object of the present application is to provide a preparation method of the above easy-activated hydrogen storage alloy, which comprises the following steps:

[0012] Step one, preparing the hydrogen storage alloy with a chemical formula of Ti x V 40 Mn y Fe z from elemental titanium, vanadium, manganese and iron and mixing uniformly;

[0013] Step two, placing the mixed raw materials into a copper crucible of a vacuum non-consumable arc furnace, then performing vacuumizing treatment, filling argon into the furnace to perform furnace washing treatment after reaching a certain pressure, and finally performing smelting under the protection of argon;

[0014] Step three, repeatedly smelting, and obtaining the hydrogen storage alloy by cooling the crucible to room temperature.

[0015] Further limit, the burning loss rate of Mn in step one is 5wt.%.

[0016] Further limit, the pressure of the furnace washing treatment in step two is 2×10 -3 Pa, and the number of times is more than 3.

[0017] Further limit, the smelting current in step two is 90-170A.

[0018] Further limit, the smelting number of times in step three is 3-5.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] (1) The present application uses Ti as the hydrogen absorption element, which can be mutually soluble with V in a wide temperature range at any ratio, and the addition of Mn helps to introduce Laves phase to improve the activation and kinetic performance of the hydrogen storage alloy, and the addition of Fe helps to improve the hydrogen absorption and desorption platform pressure. Therefore, the present application uses Ti, Mn and Fe with low price to partially replace V, which not only reduces the amount of expensive elemental vanadium and effectively reduces the cost, but also can obtain a hydrogen storage alloy meeting the industrial application requirements through reasonable component design.

[0021] (2) The hydrogen storage alloy prepared by the present application only needs to undergo one hydrogen absorption / desorption process at room temperature to be completely activated, without undergoing repeated hydrogen absorption / desorption processes at high temperature and high pressure, and the maximum hydrogen absorption amount at room temperature can be up to 3.51wt.%, and the reversible hydrogen storage amount at 363K is 2.08wt.%, which has good hydrogen storage characteristics and can be used as a candidate material for hydrogen purification, hydrogen internal combustion engine and hydrogen fuel cell equipment.

[0022] (3) The present application uses the electric arc smelting method to directly obtain the hydrogen storage alloy, and the preparation process is simple and mature, and the raw materials are cheap and easy to obtain, which is convenient for large-scale industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 Ti 30 V 40 Mn 18 Fe 12 Activation curve of the hydrogen storage alloy;

[0024] Figure 2 Ti 30 V 40 Mn 18 Fe 12 Hydrogen absorption / desorption PCT curves of the hydrogen storage alloy at 298K, 333K and 363K, respectively;

[0025] Figure 3Ti prepared for Example 2 35 V 40 Mn 22 Activation curve of Fe3 hydrogen storage alloy

[0026] Figure 4 Ti prepared for Example 2 35 V 40 Mn 22 Hydrogen absorption and desorption PCT curves of Fe3 hydrogen storage alloy at 298 K, 333 K and 363 K

[0027] Figure 5 Ti prepared for Example 3 40 V 40 Mn2Fe 18 Activation curve of hydrogen storage alloy

[0028] Figure 6 Ti prepared for Example 3 40 V 40 Mn2Fe 18 Hydrogen absorption and desorption PCT curves of hydrogen storage alloy at 298 K, 333 K and 363 K DETAILED DESCRIPTION

[0029] In order to make the above objectives, features and advantages of the present application more apparent, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0030] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without the specific details given herein, that the present application can be practiced with other than the described implementations, and that the present application can be practiced with or in conjunction with other systems, components, methods, and / or objects other than those described herein. In other instances, well-known structures, materials, or operations are not shown or described in detail in order to avoid obscuring aspects of the application.

[0031] Secondly, the "one embodiment" or "an embodiment" as used herein means that a specific feature, structure, or characteristic described in connection with the embodiment can be included in at least one implementation of the present application. The appearances of "in one embodiment" or "in an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of other embodiments.

[0032] The experimental methods used in the following examples are all conventional methods unless otherwise specified. The materials, reagents, methods and instruments used are all conventional materials, reagents, methods and instruments in the art unless otherwise specified, and can be obtained by commercial channels by those skilled in the art.

[0033] Example 1

[0034] In this embodiment, the alloy composition is designed as Ti 30 V 40 Mn18 Fe 12 , using pure titanium metal, vanadium metal, manganese metal and iron metal with purity higher than 99.5wt.% as raw materials and according to nominal composition, wherein the burning loss rate of Mn is considered to be 5wt.%.

[0035] Ti 30 V 40 Mn 18 Fe 12 The method for preparing the hydrogen storage alloy is as follows:

[0036] After the mixture is uniformly mixed, it is loaded into a copper crucible in a vacuum non-consumable arc furnace, and then vacuumized to 2x10 - 3 Pa, and then argon is filled to wash the furnace, the above washing process is repeated 3 times, and then smelting is carried out under high-purity argon protection, first smelting under a current of 90A, and slowly increasing the current, the mixture starts to melt, until the current is increased to 170A, the mixture is completely melted, and the smelting is continued under the condition of 170A, and then the crucible is cooled to room temperature to form an alloy ingot, which is turned over and smelted again, and the smelting is repeated 3 times to ensure uniformity of the alloy composition. After the surface of the alloy ingot is polished with sandpaper to remove the oxide layer, mechanical crushing treatment is carried out, and after screening, an alloy powder below 200 meshes is obtained for hydrogen storage performance test.

[0037] The above Ti 30 V 40 Mn 18 Fe 12 The activation test conditions of the hydrogen storage alloy are as follows: 1.5g of alloy powder is placed in a stainless steel reactor in a Sievert's PCT tester, and vacuumization is carried out at 673K for 1h to remove adsorbed impurity gas to improve the reaction activity; after cooling to 298K, 4MPa of hydrogen is filled to absorb hydrogen, and then vacuumization is carried out at 673K for 2h to release hydrogen, and the hydrogen absorption and release process is repeated many times until the alloy reaches the maximum hydrogen absorption capacity, and the activation is completed.

[0038] The above Ti 30 V 40 Mn 18 Fe 12 The hydrogen absorption and release PCT test conditions of the hydrogen storage alloy are as follows: the hydrogen pressure range is 0.005-4MPa, and the temperatures are 298K, 333K and 363K respectively. As shown in the table, the hydrogen storage alloy can reach the maximum hydrogen absorption capacity at the first hydrogen absorption at 298K. Figure 1 Figure 2 The hydrogen absorption and release PCT curve shows that the maximum hydrogen absorption capacity of the hydrogen storage alloy is 2.29wt.%, and the reversible hydrogen storage capacities at 298K, 333K and 363K are 1.35wt.%, 1.45wt.% and 1.41wt.% respectively. ​

[0039] Example 2

[0040] The alloy composition in this example is designed as Ti 35 V 40 Mn 22 Fe3, and pure metals of titanium, vanadium, manganese and iron with a purity higher than 99.5wt.% are used as raw materials and are dosed according to the nominal composition, wherein the burn loss rate of Mn is considered to be 5wt.%.

[0041] The Ti 35 V 40 Mn 22 Fe3hydrogen storage alloy in this example is prepared as follows:

[0042] After the mixture is uniformly mixed, it is loaded into a copper crucible in a vacuum non-consumable arc furnace, and then vacuumized to 2x10 - 3 Pa, and then argon is filled for furnace cleaning. The above furnace cleaning process is repeated 3 times, and then smelting is carried out under high-purity argon protection. First, smelting is carried out under a current of 90A, and the current is slowly increased until the alloy is completely melted under a current of 170A. The alloy ingot is cooled to room temperature, and then smelting is carried out again by turning it over. The smelting process is repeated 3 times to ensure uniformity of the alloy composition. After the surface of the alloy ingot is polished with sandpaper to remove the oxide layer, mechanical crushing treatment is carried out, and after screening, alloy powder below 200 mesh is obtained for hydrogen storage performance testing.

[0043] The above Ti 35 V 40 Mn 22 Fe3hydrogen storage alloy is activated and tested under the following conditions: 1.5g of alloy powder is placed in a stainless steel reactor in a Sievert's PCT tester, and vacuumization is carried out at 673K for 1h to remove adsorbed impurity gases to improve the reaction activity. After cooling to 298K, 4MPa of hydrogen is filled for hydrogen absorption, and then vacuumization is carried out at 673K for 2h to release hydrogen. The hydrogen absorption and release process is repeated multiple times until the alloy reaches the maximum hydrogen absorption capacity, and the activation is completed.

[0044] The above Ti 35 V 40 Mn 22 Fe3hydrogen storage alloy is activated and tested under the following conditions: 1.5g of alloy powder is placed in a stainless steel reactor in a Sievert's PCT tester, and vacuumization is carried out at 673K for 1h to remove adsorbed impurity gases to improve the reaction activity. After cooling to 298K, 4MPa of hydrogen is filled for hydrogen absorption, and then vacuumization is carried out at 673K for 2h to release hydrogen. The hydrogen absorption and release process is repeated multiple times until the alloy reaches the maximum hydrogen absorption capacity, and the activation is completed. Figure 3 As shown in the table, the hydrogen storage alloy can reach the maximum hydrogen absorption capacity at 298K after the first hydrogen absorption. Figure 4The PCT curve of hydrogen absorption and desorption shows that the maximum hydrogen absorption capacity of the hydrogen storage alloy is 3.51wt.%, and the reversible hydrogen storage capacities at 298K, 333K and 363K are 0.41wt.%, 1.25wt.% and 2.08wt.% respectively.

[0045] Example 3

[0046] In this example, the alloy composition is designed as Ti 40 V 40 Mn2Fe 18 The pure metals titanium, vanadium, manganese and iron with a purity higher than 99.5wt.% are used as raw materials and are dosed according to the nominal composition, wherein the burning loss rate of Mn is considered to be 5wt.%.

[0047] In this example, Ti 40 V 40 Mn2Fe 18 The method for preparing the hydrogen storage alloy is as follows:

[0048] After the mixture is uniformly mixed, it is loaded into a copper crucible in a vacuum non-consumable arc furnace, and then vacuumized to 2×10 - 3 Pa, and then argon is filled for furnace cleaning. The above furnace cleaning process is repeated 3 times, and then smelting is carried out under the protection of high-purity argon. First, smelting is carried out under a current of 90A, and the current is slowly increased until the current reaches 170A and the ingredients are completely melted. The smelting is continued under the condition of 170A, and then the crucible is cooled to room temperature to form an alloy ingot. The alloy ingot is turned over and smelted again, and the smelting is repeated 3 times to ensure that the alloy composition is uniform. After the surface of the alloy ingot is polished with sandpaper to remove the oxide layer, mechanical crushing treatment is carried out, and after screening, an alloy powder below 200 meshes is obtained for hydrogen storage performance test.

[0049] The above Ti 40 V 40 Mn2Fe 18 The activation test conditions of the above hydrogen storage alloy are as follows: 1.5g of alloy powder is put into a stainless steel reactor in a Sievert's PCT tester, and vacuumization is carried out at 673K for 1h to remove adsorbed impurity gas to improve the reaction activity; after cooling to 298K, 4MPa of hydrogen is filled for hydrogen absorption, and then vacuumization is carried out at 673K for 2h for hydrogen desorption. The hydrogen absorption and desorption process is repeated many times until the alloy reaches the maximum hydrogen absorption capacity, and the activation is completed.

[0050] The above Ti 40 V 40 Mn2Fe 18 The hydrogen absorption and desorption PCT test conditions of the above hydrogen storage alloy are as follows: the hydrogen pressure range is 0.005-4MPa, and the temperatures are 298K, 333K and 363K respectively. For example, Figure 5As shown, the hydrogen storage alloy can reach the maximum hydrogen absorption amount at the second hydrogen absorption at 298 K. Figure 6 The PCT curve of hydrogen absorption and desorption shows that the maximum hydrogen absorption amount of the hydrogen storage alloy is 3.47 wt.%, and the reversible hydrogen storage amounts at 298 K, 333 K and 363 K are 1.15 wt.%, 1.54 wt.% and 1.42 wt.% respectively.

[0051] Although the present application has been disclosed with reference to preferred embodiments, it is not intended to limit the present application, and any person skilled in the art can make various modifications and modifications without departing from the spirit and scope of the present application, and the protection scope of the present application should be defined by the claims.

Claims

1. An easily activated hydrogen storage alloy, characterized in that, The chemical formula of this hydrogen storage alloy is Ti. 30 V 40 Mn 18 Fe 12 Ti 35 V 40 Mn 22 Fe3 or Ti 40 V 40 Mn2Fe 18 ; Hydrogen storage alloys include BCC phase and C14 type Laves phase; This hydrogen storage alloy is made from elemental titanium, vanadium, manganese, and iron with a purity higher than 99.5 wt.%.

2. A method for preparing the easily activated hydrogen storage alloy according to claim 1, characterized in that, include: Step 1: Prepare a solution with the chemical formula Ti using elemental titanium, vanadium, manganese, and iron as raw materials. 30 V 40 Mn 18 Fe 12 Ti 35 V 40 Mn 22 Fe3 or Ti 40 V 40 Mn2Fe 18 The hydrogen storage alloy was mixed evenly; Step 2: Place the evenly mixed raw materials into the copper crucible of the vacuum non-consumable arc furnace, then perform vacuum treatment. After reaching a certain pressure, fill the furnace with argon gas for furnace cleaning treatment, and finally perform melting under argon protection. Step 3: Repeatedly melt and cool the crucible to room temperature to obtain a hydrogen storage alloy.

3. The method for preparing the easily activated hydrogen storage alloy according to claim 2, characterized in that, In step two, the smelting current is 90-170A.

4. The method for preparing the easily activated hydrogen storage alloy according to claim 2, characterized in that, The melting process in step three involves 3-5 remelting cycles.

5. The method for preparing the easily activated hydrogen storage alloy according to claim 2, characterized in that, In step one, the burn-off rate of Mn is considered to be 5 wt.%.

6. The method for preparing the easily activated hydrogen storage alloy according to claim 2, characterized in that, The furnace washing pressure in step two is 2×10 -3 Below Pa, the number of times is 3 or more.

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