Y-doped Ti-Mn-based solid hydrogen storage alloy and preparation method thereof

Abstract

The invention relates to a Y-doped Ti-Mn-based solid hydrogen storage alloy and a preparation method thereof, belongs to the technical field of hydrogen storage alloy materials, and has the advantages of easiness in activation, high hydrogen absorption and desorption speed, moderate hydrogen absorption and desorption plateau pressure and long cycle life. The invention provides a Y-doped Ti-Mn-based hydrogen storage alloy, which is characterized in that the chemical general formula of the hydrogen storage alloy is Ti1-x-yYxZryMn2-w-vVwFev, in the formula, x, y, w and v represent atomic ratios, 0.02 < = x < = 0.08, 0.05 < = y < = 0.15, 0.3 < = w < = 0.5, and 0.1 < = v < = 0.2. The hydrogen storage alloy is excellent in hydrogen storage performance and can be completely activated by absorbing hydrogen for the first time under the conditions of 25 DEG C and 3 MPa, the hydrogen storage capacity is larger than or equal to 1.90 wt%, the hydrogen absorption plateau pressure is larger than or equal to 0.35 MPa, the hydrogen desorption plateau pressure is smaller than or equal to 0.26 MPa, and the hydrogen absorption retention rate of the alloy is larger than or equal to 97.52% after the alloy is cycled for 1000 times.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of titanium-based hydrogen storage alloy materials, and relates to a Ti-Mn-based hydrogen storage alloy and a preparation method thereof, in particular to an easily activated Ti-Y-Zr-Mn-V-Fe-based hydrogen storage alloy and a preparation method thereof. BACKGROUND

[0002] In recent years, hydrogen has attracted widespread attention as a clean energy source due to its high heat value and zero carbon emissions. However, the storage and transportation of hydrogen remains one of the main bottlenecks restricting the application of hydrogen fuel cell technology. Due to the low density of hydrogen, traditional hydrogen storage methods such as high-pressure gas storage and liquid hydrogen storage require large storage containers, which not only increases the volume and weight of the system, but also brings significant challenges in safety and transportation. In contrast, solid-state hydrogen storage alloys have become an ideal solution for hydrogen supply in hydrogen fuel cell systems due to their high energy efficiency, high volumetric hydrogen storage density, and superior safety. Therefore, the development of new solid-state hydrogen storage alloys is of great significance for promoting the widespread application of hydrogen fuel cell technology.

[0003] Among all solid-state hydrogen storage alloys, TiMn2 alloy has the advantages of good hydrogen absorption and desorption kinetic performance, ability to absorb and desorb hydrogen at room temperature, and low cost, and is considered to be the most suitable solid-state hydrogen storage alloy for proton exchange membrane hydrogen fuel cells. Therefore, a large number of researchers at home and abroad have conducted systematic research on Ti-Mn-based hydrogen storage alloys.

[0004] Currently, in the prior art, TiMn2 alloy generally has the problems of high activation condition (hydrogen pressure of 5 MPa or more is required at room temperature), low effective hydrogen storage capacity of the material, and poor hydrogen absorption and desorption plateau characteristics. SUMMARY

[0005] In view of the above analysis, the embodiments of the present application aim to provide an easily activated rare earth-doped Ti-Mn-based hydrogen storage alloy and a preparation method thereof, to solve at least one of the problems of high activation condition (hydrogen pressure of 5 MPa or more is required at room temperature), low effective hydrogen storage capacity of the material, and poor hydrogen absorption and desorption plateau characteristics of the current Ti-Mn-based hydrogen storage alloy.

[0006] The present application discloses a Y-doped Ti-Mn-based hydrogen storage alloy, the specific composition of the alloy is Ti 1-x- y Y x Zr y Mn 2-w-v V w Fe v , wherein x, y, w, and v represent atomic ratios, 0.02≤x≤0.08, 0.05≤y≤0.15, 0.3≤w≤0.5, and 0.1≤v≤0.2.

[0007] The atomic number of the Ti-Mn-based hydrogen storage alloy Y is 0.02≤x≤0.08, for example, can be 0.02, 0.05, 0.08, the atomic number of Zr is 0.05≤y≤0.15, for example, can be 0.05, 0.01, 0.15, the atomic number of V is 0.3≤w≤0.5, for example, can be 0.3, 0.4, 0.5, the atomic number of Fe is 0.1≤v≤0.2, for example, can be 0.1, 0.15, 0.2, but not limited to the listed values, other values not listed in the above value range are also applicable.

[0008] Specifically, the hydrogen storage alloy has a multi-phase structure, containing C14-Laves phase, Y2O3 phase.

[0009] The application also provides a preparation method of the hydrogen storage alloy, specifically comprising the following steps:

[0010] (1) selecting metal elements or alloy compounds as raw materials, and dosing according to the above alloy chemical composition, considering subsequent melting and volatilization, and appropriately increasing the addition amount of the corresponding elements during dosing;

[0011] (2) adding the prepared raw materials to a water-cooled copper crucible for melting, heating the raw materials to a molten state and keeping for a period of time, and after multiple times of ingot turning, pouring the liquid alloy into a mold, and cooling to obtain an alloy ingot.

[0012] (3) mechanically crushing the alloy ingot and sieving to obtain a finished hydrogen storage alloy powder.

[0013] Further, in step (1), the increase amount of Mn and rare earth is 4% to 7% of the calculated amount.

[0014] Further, in step (2), the specific operation of arc melting is: vacuumizing to 5×10 -2 ~ 1×10 -5 Pa, filling 0.01 to 0.05 MPa pressure of argon as a protective gas, the melting temperature is 1450℃ to 1550℃, keeping for 1 to 3 minutes after complete melting, and the alloy is turned for 5 to 6 times.

[0015] Further, in step (3), the alloy is mechanically crushed and sieved through a 100 mesh sieve to obtain a solid-state hydrogen storage alloy powder product with a diameter of ≤60μm.

[0016] Compared with the prior art, the application can at least achieve one of the following beneficial effects:

[0017] 1. The Y-doped Ti-Mn-based solid-state hydrogen storage alloy provided by the application has low activated hydrogen pressure, good hydrogen absorption and desorption platform characteristics, and high cycle life.

[0018] The Y-doped Ti-Mn-based solid-state hydrogen storage alloy provided by the present application has good activation performance and comprehensive hydrogen storage performance, the hydrogen storage capacity is ≥1.90wt%, the hydrogen absorption platform pressure is ≥0.35MPa, and the hydrogen desorption platform pressure is ≤0.26MPa; and the activation can be completed after one hydrogen absorption and desorption cycle under the condition of 25℃ and 3MPa.

[0019] The Y-doped Ti-Mn-based solid-state hydrogen storage alloy provided by the present application has good activation performance and comprehensive hydrogen storage performance, the hydrogen storage capacity is ≥1.90wt%, the hydrogen absorption platform pressure is ≥0.35MPa, and the hydrogen desorption platform pressure is ≤0.26MPa; and the activation can be completed after one hydrogen absorption and desorption cycle under the condition of 25℃ and 3MPa.

[0020] 2. The present application also discloses a preparation method of the Y-doped Ti-Mn-based solid-state hydrogen storage alloy, wherein metal raw materials are first proportioned according to chemical compositions, and then melted in an arc melting furnace to obtain a Ti-Y-Zr-Mn-V-Fe alloy with uniform composition; and then the alloy is sequentially subjected to mechanical crushing and metal sieve screening to obtain a solid-state hydrogen storage alloy powder with easy activation and high performance. BRIEF DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings, which form a part of the present application, are intended to provide further understanding of the present application, and the illustrative embodiments of the present application and their description serve the purpose of explaining the present application. The accompanying drawings should not be regarded as a limitation of the present application. In the accompanying drawings:

[0022] Figure 1 The XRD energy spectrum of the Y-doped Ti-Mn-based solid-state hydrogen storage alloy prepared in Example 1 of the present application;

[0023] Figure 2 The SEM scanning electron microscope images of the Y-doped Ti-Mn-based solid-state hydrogen storage alloy prepared in Example 1 of the present application before hydrogen absorption (a) and after hydrogen desorption (b);

[0024] Figure 3 The EDS energy spectrum of the Y-doped Ti-Mn-based solid-state hydrogen storage alloy prepared in Example 1 of the present application;

[0025] Figure 4 The isothermal hydrogen absorption curve of the Y-doped Ti-Mn-based solid-state hydrogen storage alloy prepared in Example 1 of the present application;

[0026] Figure 5The isothermal hydrogen desorption curve of the Y-doped Ti-Mn-based solid-state hydrogen storage alloy prepared in Example 1 of the present application is shown in the following figure:

[0027] Figure 6 The PCT curve of the Y-doped Ti-Mn-based solid-state hydrogen storage alloy prepared in Example 1 of the present application is shown in the following figure:

[0028] Figure 7 The Van't Hoff curve of the Y-doped Ti-Mn-based solid-state hydrogen storage alloy prepared in Example 1 of the present application is shown in the following figure, which is fitted according to the Van't Hoff equation:

[0029] Figure 8 The 1000-cycle long cycle life attenuation histogram of the Y-doped Ti-Mn-based solid-state hydrogen storage alloy prepared in Example 1 of the present application is shown in the following figure. DETAILED DESCRIPTION

[0030] The detailed description set forth below of the exemplary implementations of the application describes and discloses the best modes contemplated of practicing the application, and to thereby convey the scope of the application to those skilled in the art.

[0031] It should be understood that the terms used herein are for the purpose of describing particular embodiments and are not intended to limit the application. Additionally, for a range of values of a parameter, unless otherwise stated, each intervening value by each intervening value, as well as each individual value of the recited range, is also contemplated. In each case, the values are inclusive of the endpoints. The same applies to every range of values.

[0032] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, the preferred methods and materials are described. All publications mentioned herein are incorporated by reference to disclose and describe the methods and / or materials in connection with which the publications are cited. In case of conflict, the content of the present specification will control.

[0033] Various modifications and changes can be made to the specific embodiments of the present application described herein without departing from the scope or spirit of the application. Other embodiments of the application will be apparent to those of ordinary skill in the art from the description and examples presented herein. The description and examples presented herein are meant as illustrative only and are not intended to limit the scope of the application.

[0034] With respect to the terms "comprising", "containing", "having", "including", and the like used herein, these terms are used in their open-ended, non-limiting sense to encompass the presence of one or more elements, features, or components, but do not preclude the presence or addition of one or more other elements, features, or components.

[0035] Example 1

[0036] The present embodiment provides a Y-doped Ti-Mn-based solid-state hydrogen storage alloy, the composition of the hydrogen storage alloy is Ti 0.85 Y 0.05 Zr 0.1 Mn 1.45 V 0.4 Fe 0.15 , and the main hydrogen absorption phase of the hydrogen storage alloy is a C14-Laves phase.

[0037] The present embodiment also provides a preparation method of the Y-doped Ti-Mn-based hydrogen storage alloy, and the preparation steps are as follows:

[0038] (1) according to the chemical formula Ti 0.85 Y 0.05 Zr 0.1 Mn 1.45 V 0.4 Fe 0.15 , select block rare earth element Y, sponge Ti, sponge Zr, electrolytic Mn, metal V and Fe. The purity of these metals is ≥ 99.5%, and the mass ratio is weighed, wherein the sponge Ti is 12.51g, the sponge Zr is 2.31g, the electrolytic Mn is 26.5g, the metal V is 6.26g, and the metal Fe is 2.6g. Put the weighed metal into the copper crucible of the vacuum arc melting furnace, vacuumize to a vacuum degree of 3×10 -3 Pa or more, then fill high-purity argon protection gas to -0.05MPa, the melting temperature is 1450℃, keep for 5 minutes after all the metal is melted, and turn the ingot 5 times during the melting process to ensure uniform composition. After the melting is completed, the uniformly mixed molten metal is loaded into a mold, and a button-shaped Ti 0.85 Y 0.05 Zr 0.1 Mn 1.45 V 0.4 Fe 0.15 alloy ingot is obtained after cooling.

[0039] (2) mechanically crush the Ti 0.85 Y 0.05 Zr 0.1 Mn 1.45 V 0.4 Fe 0.15 alloy ingot, and pass through a 100 mesh metal sieve to obtain a solid-state hydrogen storage alloy powder finished product with a diameter of ≤ 60μm.

[0040] In an argon environment glove box, take Ti 0.85 Y 0.05 Zr 0.1 Mn 1.45 V 0.4 Fe0.15 The alloy powder 1 g was placed in a sample crucible, and then the activation performance, hydrogen absorption and desorption performance, and long cycle life of the alloy powder were tested by a Sieverts type full-automatic gas absorption / desorption equipment. The sample was subjected to isothermal hydrogen absorption test at 25℃ and 3 MPa, isothermal hydrogen desorption test at 25℃ and 5 x 10 -3 MPa, and PCT test at 25℃, 30℃, and 45℃.

[0041] Comparative Example 1 (TiMn2)

[0042] According to the chemical formula TiMn2, 16.9 g of sponge Ti and 35 g of electrolytic Mn were placed in an arc melting crucible, vacuumized to a vacuum degree of 3 x 10 -3 Pa or above, high-purity argon protective gas was filled to -0.05 MPa, the melting temperature was 1450℃, and the ingot was turned 5 times during the melting process to ensure uniform composition. After the melting was completed, the uniformly mixed molten metal was loaded into a mold, and a button-shaped TiMn2 alloy ingot was obtained after cooling. After mechanical crushing and sieving through a 100-mesh sieve, the corresponding alloy powder was obtained. 1 g of TiMn2 powder was taken in a sample crucible in an argon environment glove box, and then the activation performance and hydrogen absorption and desorption performance of the alloy powder were tested by a Sieverts type full-automatic gas absorption / desorption equipment. The sample was subjected to isothermal hydrogen absorption test at 25℃ and 3 MPa, isothermal hydrogen desorption test at 25℃ and 5 x 10 -3 MPa.

[0043] Comparative Example 2 (Ti 0.9 Zr 0.1 Mn 1.45 V 0.4 Fe 0.15 )

[0044] Compared with Comparative Example 1, the difference of the present comparative example is that the metals added during melting are Ti, Zr, Mn, V, and Fe, and the mass of each metal added is 13.4 g, 2.84 g, 27 g, 6.35 g, and 2.6 g, respectively; the other conditions are the same as those of Comparative Example 1.

[0045] Effect Example 1

[0046] The X-ray diffraction patterns of the Y-doped Ti-Mn-based solid-state hydrogen storage alloy prepared by the method of the present application and Comparative Examples 1 and 2 were determined, as shown in Figure 1 The phase composition of the Ti-Mn-based solid-state hydrogen storage alloy of Example 1 is mainly C14-Laves phase, and there is also a small amount of Y2O3 phase. As can be seen from Comparative Example 1 and Comparative Example 2, the diffraction peak of the Ti-Mn-based hydrogen storage alloy of Example 1 shifts to the left, which is due to the large atomic radius of the rare earth element Y, and the increase in the unit cell volume after doping.

[0047] Effect Example 2

[0048] Figure 2 The scanning electron microscope images (SEM) of the Y-doped Ti-Mn-based solid-state hydrogen storage alloy prepared by the method of the present application before and after hydrogen absorption and desorption are shown in the figure. As can be seen from the figure, the alloy powder before hydrogen absorption has larger particles (average size: ), and the alloy powder after hydrogen absorption and desorption is obviously refined (average size: ). Meanwhile, the enlarged observation of the alloy powder after hydrogen desorption shows that after multiple hydrogen absorption and desorption, the alloy powder surface has obvious micro-cracks, which provides more channels for hydrogen diffusion, and explains the improvement of the activation performance of the hydrogen storage alloy from the morphology aspect.

[0049] The energy spectrum (EDS) of the Y-doped Ti-Mn-based solid-state hydrogen storage alloy prepared by the method of the present application is determined, as shown in the figure. Figure 3 As can be seen from the figure, the elements in the hydrogen storage alloy are uniformly distributed, indicating that the Ti-Mn-based hydrogen storage alloy without composition segregation can be successfully prepared by the above preparation method.

[0050] Effect Example 3

[0051] Figure 4 With Figure 5 The isothermal hydrogen absorption and desorption curve of the Y-doped Ti-Mn-based solid-state hydrogen storage alloy prepared by the method of the present application is shown in the figure. The results show that the hydrogen absorption activation energy of the Y-doped Ti-Mn-based hydrogen storage alloy is reduced to 8.81 kJ / mol.

[0052] Figure 6 The pressure-composition-temperature (PCT) test curve of the Y-doped Ti-Mn-based solid-state hydrogen storage alloy prepared by the method of the present application is shown in the figure. As can be seen from the figure, the hydrogen absorption plateau pressure of the Y-doped Ti-Mn-based solid-state hydrogen storage alloy at 25℃ is reduced to 0.35 MPa, the hydrogen desorption plateau pressure is reduced to 0.26 MPa, and the hysteresis coefficient H f is reduced to 0.29 (H f = ln (hydrogen absorption plateau pressure / hydrogen desorption plateau pressure)), and the maximum hydrogen absorption amount at this temperature is 1.90 wt%. It is thus shown that the Ti-Mn-based solid-state hydrogen storage alloy prepared by Y element doping has high effective hydrogen absorption amount, good plateau characteristics, high cycle life, and excellent comprehensive hydrogen storage performance.

[0053] Figure 7 The Van't Hoff curve of the Y-doped Ti-Mn-based solid-state hydrogen storage alloy prepared by the method of the present application is shown in the figure. The hydrogen absorption enthalpy change of the alloy is fitted by the curve to be: -24.28 kJ / mol, and the hydrogen absorption entropy change is: -92.04 J / mol·K. The material has good thermodynamic performance.

[0054] Figure 7The high and low temperature life cycle column chart of the Y-doped Ti-Mn-based solid-state hydrogen storage alloy prepared by the method is shown. The hydrogen storage alloy is subjected to hydrogen absorption at 315K and hydrogen desorption at 423K, and the hydrogen pressure is 1.6MPa. After 1000 high and low temperature hydrogen absorption and desorption cycles, the hydrogen storage capacity retention rate of the alloy is 97.52%, and the alloy has good cycle life.

[0055] In summary, the solid-state hydrogen storage alloy has good activation performance, excellent platform characteristics, high hydrogen storage capacity and excellent cycle service life. The performance meets the requirements of various uses for hydrogen storage materials. Compared with similar alloys at home and abroad, the hydrogen storage performance of the alloy is significantly improved, and the alloy has obvious advantages.

[0056] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A Y-doped Ti-Mn-based solid hydrogen storage alloy, characterized in that, The hydrogen storage alloy has the general chemical formula Ti. 1-x- y Y x Zr y Mn 2-w-v V w Fe v In the formula, x, y, w, and v represent the atomic ratios, where 0.02 ≤ x ≤ 0.08, 0.05 ≤ y ≤ 0.15, 0.3 ≤ w ≤ 0.5, and 0.1 ≤ v ≤ 0.

2.

2. The Ti-Mn-based hydrogen storage alloy according to claim 1, characterized in that: The alloy has a multiphase structure containing C14-Laves phase and Y2O3 phase.

3. A method for preparing a Y-doped Ti-Mn-based solid hydrogen storage alloy according to any one of claims 1 to 2, characterized in that, Follow these steps in sequence: (1) Select a metallic element or alloy compound as raw material, and make the batch according to the alloy chemical composition described in claim 1. Considering subsequent melting and volatilization, the amount of corresponding elements added during batching should be appropriately increased. (2) Add the raw materials prepared in step (1) to the water-cooled copper crucible for melting, heat the raw materials to the molten state and keep them at the temperature for a period of time, and after multiple ingot turnings, pour the liquid alloy into the mold and cool to obtain the alloy ingot. (3) The alloy ingot is mechanically crushed and sieved through a metal sieve to obtain powdered alloy, so as to obtain finished hydrogen storage alloy powder.

4. The preparation method according to claim 3, characterized in that: In step (1), the increase in Mn and Y is 4% to 7% of the calculated speculative amount in step (1).

5. The preparation method according to claim 3, characterized in that: The specific operation of arc melting in step (2) is as follows: evacuate to 5×10 -2 ~1×10 -5 After Pa, argon gas at a pressure of 0.01 to 0.05 MPa is introduced as a protective gas. The melting temperature is 1450℃ to 1550℃. After complete melting, the temperature is held for 1 to 3 minutes, and the alloy ingot is turned over 5 to 6 times.

6. The preparation method according to claim 3, characterized in that: The alloy in step (3) is mechanically crushed and then passed through a 100-mesh sieve to obtain a solid hydrogen storage alloy powder product with a diameter ≤60μm.

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