TiFe-based hydrogen storage material and activation method thereof

Abstract

The invention provides a hydrogen storage material, the composition of which is TixFeyMnzNba, x is more than or equal to 1.0 and less than or equal to 1.2, y is more than or equal to 0.8 and less than or equal to 0.9, z is more than or equal to 0.1 and less than or equal to 0.2, and a is more than or equal to 0.01 and less than or equal to 0.2. And further preferably, the material is any one selected from the group consisting of 0.8% of TiFe, 0.1% of Mn, 0.1% of Nb, 0.05% of Zr, 0.8% of Ti, 0.1% of Mn, 0.05% of Nb, 0.05% of Zr, 0.05% of Y, 0.8% of Ti, 0.2% of Mn, 0.05% of Nb, 0.05% of Zr, 0.05% of Y, 0.8% of Ti, 0.2% of Mn, 0.15% of Nb, 0.05% of Zr and 0.05% of Y. The invention also discloses a method for preparing and activating the hydrogen storage material. The method comprises the following steps: preparing the hydrogen storage material; carrying out heat treatment on the cast ingot in a vacuum hot-pressing furnace; and carrying out linear cutting and mechanical crushing on the ingot subjected to heat treatment, then screening through a 100-mesh sieve, and carrying out ball milling for 3 hours to obtain alloy powder. The obtained hydrogen storage material can store 1.7 wt.% of hydrogen within 5 min, and has a wide application prospect.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to TiFe-based hydrogen storage materials and a preparation method thereof, in particular to an easily activated Ti-Fe-based hydrogen storage material suitable for high-temperature applications and a preparation method thereof, and further relates to an activation method of the TiFe-based hydrogen storage material. BACKGROUND

[0002] The development of renewable energy such as solar energy, wind energy, biomass energy, etc. becomes particularly important to solve the above problems, and these renewable energies are gradually mastered by people and the technology is becoming mature. However, the storage and consumption of energy have become limiting factors in practical application, and need to be solved as soon as possible. In the current energy storage scheme, storing hydrogen into metal to generate hydride becomes a safe and stable scheme.

[0003] TiFe alloy has become a representative hydrogen storage alloy due to its relatively low cost and the ability to absorb and release hydrogen under relatively mild conditions. TiFe has a cubic CsCl-type structure, and the hydrogen storage capacity can reach 1.81 wt.% H2 at room temperature, and the hydrogen absorption platform pressure is low, with comprehensive room temperature hydrogen storage performance. However, the activation conditions of TiFe alloy are harsh, and it needs to absorb hydrogen at 673K and 4MPa H2 for a long time to be fully activated, which becomes an obstacle to the application of the alloy. When the content of Ti exceeds the stoichiometric ratio of TiFe, β-Ti solid solution will appear, and this secondary phase will first react with H2 to generate TiH2 during the activation process. The TiH2 phase is too stable and is not easy to decompose at low temperature, and exists in the form of hydride, which will reduce the hydrogen absorption capacity of the alloy. If the content of Ti is insufficient, TiFe2 phase will be generated, which coexists with TiFe matrix. This phase is difficult to react with H2, and a high content will greatly reduce the hydrogen absorption capacity of the alloy. Therefore, to solve the above problems, a new process is needed to design a chemical composition and prepare TiFe alloy.

[0004] CN 120055271A discloses a preparation method of a TiFe0.8Mn0.2 alloy doped with a nano-magnesium solid block tablet material. The prepared TiFe0.8Mn0.2 alloy is respectively added with 5wt.% of other elements (Mg, nano-magnesium, Cu, Al, Zn or C powder), and it is found that the addition of Mg does not change the crystal structure, but the interplanar spacing and cell parameters are improved, which helps to improve the hydrogen absorption capacity and rate, but the improvement is quite limited.

[0005] CN119351849A discloses a TiFe-based alloy with a dispersed Y phase, which has a chemical formula of Ti47.5Y2.5Fe40Mn10. The alloy solves the problems of high cost or active chemical properties of some added elements, difficult smelting preparation and actual use, and affects the production safety. The designed alloy composition is simple and safe, but the hydrogen storage performance of the TiFe-based alloy still needs to be improved. SUMMARY

[0006] According to one aspect of the present application, a Ti-Fe-based hydrogen storage material is provided, which further contains Mn and Nb elements, and has an alloy composition of Ti x Fe y Mn z Nb a , wherein x, y, z, a are atomic ratios, 1.0≤x≤1.2, 0.8≤y≤0.9, 0.1≤z≤0.2, 0.01≤a≤0.2.

[0007] According to one embodiment of the present application, preferably, the Ti-Fe-based hydrogen storage material further contains a Zr element, and has an alloy composition of Ti x Fe y Mn z Nb a Zr b , wherein x, y, z, a, b are atomic ratios, 1.0≤x≤1.1, 0.8≤y≤0.9, 0.1≤z≤0.2, 0.05≤a≤0.2, 0.05≤b≤0.2.

[0008] According to one embodiment of the present application, preferably, the hydrogen storage material further contains a Y element, and has an alloy composition of Ti x Fe y Mn z Nb a Zr b Y c , wherein x, y, z, a, b, c are atomic ratios, 1.0≤x≤1.1, 0.80≤y≤0.85, 0.1≤z≤0.2, 0.05≤a≤0.15, 0.05≤b≤0.15, 0.05≤c≤0.15.

[0009] Even further preferably, the alloy composition is x=1.0, y=0.8, 0.1≤z≤0.2, 0.05≤a≤0.15, 0.05≤b≤0.15, 0.05≤c≤0.15. Even further preferably, the alloy composition is TiFe 0.8 Mn 0.1 Nb 0.1 Zr 0.05 , TiFe 0.8 Mn 0.1Nb 0.05 Zr 0.05 Y 0.05 , TiFe 0.8 Mn 0.2 Nb 0.05 Zr 0.05 Y 0.05 , TiFe 0.8 Mn 0.2 Nb 0.15 Zr 0.05 Y 0.05 any one of them.

[0010] According to one aspect of the present application, there is provided a method for activating any one of the Ti-Fe based hydrogen storage materials as described above, comprising the following steps: (1) hydrogen storage material preparation process According to the elemental composition of the alloy, since Mn is volatile, 5wt.% of Mn is additionally added to ensure the accuracy of the batching, and the purity of each raw material of the hydrogen storage material is preferably above 99.5%; The prepared material is placed in a copper crucible of an electric arc furnace, vacuumized and filled with argon, and circulated for several times, for example, preferably 3-4 times, and then the melting is started, preferably, the current during the melting process of the electric arc furnace is between 200-350A, and the vacuum degree before melting should be controlled at 5x10 -3 Pa or below; During the melting process, the ingot is repeatedly turned over four times, and each melting time is 1-10min, preferably 2-7min, and more preferably 3-5min, and the current does not exceed 350A, and after the melting is completed, the sample is taken out after cooling in the electric arc furnace for 20min; (2) hydrogen storage material heat treatment process After obtaining the ingot of the hydrogen storage material, the ingot is heat treated in a vacuum hot pressing furnace, and the temperature is raised to 1100℃ at a temperature rising rate of not more than 10° / min, and then the furnace is cooled after holding for 6h; (3) hydrogen storage material ball milling process The ingot after heat treatment is wire cut into small block samples, and then the small block samples are mechanically broken, and then sieved through a 100 mesh sieve, and the sieved particles are ball milled in a high-energy ball mill for 3h to obtain an alloy powder.

[0011] According to one embodiment of the present application, it is further preferred that, in the hydrogen storage material ball milling process, the ball-to-material ratio is 10-15:1, the rotation speed is 700-800r / min, and the ball milling time is 3-4h.

[0012] According to one embodiment of the present application, it is further preferred that during the ball milling process of the hydrogen storage material, the ball milling process is cooled down for a certain period of time to ensure the normal operation of the equipment and the heat is dissipated even to avoid affecting the ball milling effect, preferably every 30 min of operation, 10 min of cooling.

[0013] According to one embodiment of the present application, it is further preferred that during the ball milling process of the hydrogen storage material, the average size of the hydrogen storage material alloy powder after ball milling should be between 40-50 μm. BRIEF DESCRIPTION OF DRAWINGS

[0014] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which like reference characters refer to like elements throughout. The accompanying drawings are intended to provide a further understanding of embodiments of the present disclosure, and are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and serve to explain the present disclosure, and do not limit the present disclosure. In the drawings, like reference numerals refer to like elements throughout.

[0015] Figure 1 shows the hydrogen storage material TiFe0.85+5wt.%Mn according to embodiment 1 of the present application 0.85 +5wt.%Mn, TiFe0.90+5wt.%Mn and TiFe0.95+5wt.%Mn, respectively; 0.90 +5wt.%Mn, TiFe0.90+5wt.%Mn and TiFe0.95+5wt.%Mn, respectively; 0.95 +5wt.%Mn alloy particle phase composition XRD pattern, wherein (a) particle XRD pattern, (b) local enlarged view; Figure 2 shows the activation curve of the alloy according to embodiment 1 of the present application at 350℃, 4MPa H2, wherein (a) TiFe0.85+5wt.%Mn, (b) TiFe0.90+5wt.%Mn and TiFe0.95+5wt.%Mn, respectively; Figure 3 shows the hydrogen absorption kinetics curve of the alloy at different temperatures according to embodiment 1 of the present application, wherein (a) TiFe0.85+5wt.%Mn, (b) TiFe0.90+5wt.%Mn and TiFe0.95+5wt.%Mn; Figure 4 shows the backscattered electron micrograph of TiFe0.8Mn0.1 alloy at different heat treatment temperatures according to embodiment 2 of the present application, wherein (a) as-cast alloy (b) 700℃ (c) 800℃ (d) 1100℃; Figure 5 shows the backscattered electron micrograph of TiFe0.8Mn0.2 alloy at different heat treatment temperatures according to embodiment 3 of the present application, wherein (a) as-cast alloy (b) 700℃ (c) 800℃ (d) 1100℃; Figure 6Activation curves of the alloys of Examples 2 and 3 according to the present invention after heat treatment at 700° C. are shown: (a) TiFe0.8Mn0.1 (b) TiFe0.8Mn0.2; Figure 7 shows the hydrogen absorption curve of the TiFe0.8Mn0.1 alloy of Example 2 of the present invention after heat treatment at 700°C; Figure 8 shows the hydrogen absorption curve of TiFe0.8Mn0.2 after heat treatment at 700°C according to Example 3 of the present invention; Figure 9 The activation hydrogen absorption curves of the alloys prepared in Examples 4-6 of the present invention are shown, wherein (a) (b) (c) are TiFe 0.8 Mn 0.1 Nb 0.1 Zr 0.05 Alloy, TiFe 0.8 Mn 0.1 Nb 0.05 Zr 0.05 Y 0.05 Alloy, Ti 1.2 Fe 0.8 Mn 0.2 Nb 0.1 Activation curve of the alloy.

[0016] Figure 10 The hydrogen absorption kinetic curves of the alloys prepared in Examples 4-6 of the present invention at different temperatures are shown, wherein (a), (b), and (c) are TiFe 0.8 Mn 0.1 Nb 0.1 Zr 0.05 Alloy, TiFe 0.8 Mn 0.1 Nb 0.05 Zr 0.05 Y 0.05 Alloy, Ti 1.2 Fe 0.8 Mn 0.2 Nb 0.1 Hydrogen absorption kinetics curve of the alloy; Figure 11 This is the hydrogen absorption curve of the alloy prepared in Example 7 of the present invention at 100°C and 4MPaH2. DETAILED DESCRIPTION

[0017] To make the objectives, technical solutions, and benefits of the present invention more intuitive, the following will fully and clearly describe the technical solutions of the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments of the present disclosure. It should be understood that the present disclosure is not limited to the example embodiments described herein.

[0018] The specific parameters of the experimental test method are as follows: 1. XRD data: The examples are tested by using a Bruker X-ray diffractometer, and the test conditions are as follows: Cu kα ray is used, and the angle is 20-90°.

[0019] 2. SEM data: The microstructure, surface morphology of the alloy before and after hydrogen absorption, and the powder surface shape are observed by using a field emission scanning electron microscope, and the element distribution of different phases is analyzed by using energy dispersive X-ray spectroscopy (EDS).

[0020] 3. Hydrogen storage data: The PCT PRO equipment produced by the French Seta Ram Instrument Company is used for hydrogen storage test, and the activation test is carried out at 4 MPa H2. 1 g of powder is activated at 100°C and 300°C, and then the hydrogen absorption kinetics test is carried out at 70°C, 55°C, 40°C and 25°C. Examples

[0021] In the following examples, Example 1 mainly explores and optimizes the content ratio of Ti and Fe elements as the main element.

[0022] Ingredients: According to the stoichiometric ratio of TiFe x +5wt.%Mn (x is the atomic ratio, x=0.85, 0.90, 0.95, and the content of Mn element is 5wt.% relative to the total mass of TiFe, the same below) alloy composition, in addition, considering the volatilization of Mn element, 5wt.% of Mn is added based on the calculated Mn content, and the purity of each element raw material is greater than 99.5%, and the total mass is 50g; Melting: After batching, vacuum arc furnace is used for melting, first low vacuum, the pressure gauge reaches-0.1 MPa below, then fill argon, stop filling argon when the pressure gauge reaches-0.05 MPa. Repeat the gas washing 3~4 times. The current is controlled below 350A during the melting process to prevent the volatilization of Mn element, and the melting is repeated 4~5 times to make TiFe 0.85 +5wt.%Mn alloy, TiFe 0.90 +5wt.%Mn alloy, TiFe 0.95 +5wt.%Mn alloy ingot.

[0023] The XRD test is carried out on the three kinds of alloy ingots, and the results are shown in Figure 1 TiFe x +5wt.%Mn (x=0.85, 0.90, 0.95) alloy particle phase composition XRD pattern. From Figure 1It can be seen that with the increase of Fe content, the diffraction peak of TiFe phase increases and shifts to the right. This is because the atomic radius of Fe is small, and the increase of Fe content leads to lattice shrinkage, decrease of lattice constant, decrease of interplanar spacing, increase of θ angle, and right shift of diffraction peak. Since the Ti / Fe ratio in the alloy increases with the increase of Fe content, the content of TiFe phase in the alloy increases, and the diffraction peak intensity increases.

[0024] As Figure 2 The activation curve of the as-cast TiFex+5wt.%Mn (x=0.85, 0.90, 0.95) alloy particles. Figure 2 (a) is the activation curve of the TiFe 0.85 +5wt.%Mn alloy, it is found that the alloy does not need an incubation period for the first hydrogen absorption, and can completely absorb hydrogen within 5 min, with a relatively fast hydrogen absorption rate, indicating that the alloy has excellent activation performance.

[0025] Figure 2 (b) is the activation curve of the TiFe0.90+5wt.%Mn alloy, it is found that the hydrogen absorption content of the alloy is low and the hydrogen absorption rate is slow in the first two activations, and the hydrogen absorption rate is significantly improved in the third activation, with a hydrogen absorption amount of 0.7wt.%, compared with the x=0.85 alloy, the activation performance of the alloy is poor, the inventors of the present application believe that this is because the second phase of the alloy precipitates less, the phase boundary area of the alloy is greatly reduced, the activation sites provided are also relatively reduced, the H atom diffusion channel is less, resulting in poor activation hydrogen absorption performance, but the hydrogen absorption amount still meets the requirements.

[0026] Figure 2 (c) is the activation curve of the TiFe0.95+5wt.%Mn alloy. During the first activation process, the alloy has an incubation period of about 10 min, and the hydrogen absorption rate is slow, and the hydrogen absorption amount is low in the subsequent two activations, less than 0.5wt.%, and the activation performance is relatively poor, which is because the TiFe2 phase of the second phase of the alloy does not absorb hydrogen, and a high content will reduce the hydrogen absorption amount of the alloy, resulting in poor activation performance.

[0027] Therefore, from the perspective of hydrogen absorption rate, the preferred Fe atomic ratio is 0.85-0.90.

[0028] Further, four temperatures were selected for hydrogen absorption kinetics test of the alloy, as shown in Figure 3 As Figure 3It can be seen that with the decrease of temperature, the hydrogen absorption amount of the alloy generally shows an upward trend, which is because the hydrogen absorption reaction is an exothermic reaction, and the lower the temperature, the higher the reaction process. In addition, it is found that at 55℃ and 70℃, the three alloys all have obvious incubation period, the inventors of the present application believe that this is because the temperature is high, the equilibrium pressure of the alloy is high, and the hydrogen absorption rate of the alloy is slow, so there is a certain incubation period. In addition, it is found that the hydrogen absorption amount of the x=0.90 alloy is the highest, and the hydrogen absorption amount of the x=0.95 alloy is the lowest. This is because the chemical composition of the x=0.90 alloy is closer to the standard chemical composition, and the content of TiFe phase is higher. As the main hydrogen absorption phase, the content of the alloy is high, and the hydrogen absorption amount of the alloy is improved; the x=0.95 alloy contains a large amount of TiFe2 phase, which does not absorb hydrogen, and the high content will lead to the decrease of the hydrogen absorption amount of the alloy.

[0029] Therefore, from the point of view of hydrogen absorption amount, the most preferred Fe atomic ratio is 0.85-0.90.

[0030] Therefore, the inventors of the present application comprehensively consider the hydrogen absorption rate and the hydrogen absorption amount, and the atomic ratio of Fe is 0.85-0.90. In order to realize a wider range of activation methods of TiFe-based hydrogen storage materials, the inventors of the present application designed examples 2 and 3, mainly focusing on TiFe 0.8 Mn 0.1 alloy, TiFe 0.8 Mn 0.2 alloy as the object, and optimized the activation process of TiFe-based hydrogen absorption materials. Example

[0031] Except that the components are different, the remaining steps are as described in example 1, to prepare TiFe 0.8 Mn 0.1 alloy.

[0032] The alloy was heated at 700℃, 800℃ and 1100℃, and then cooled with the furnace, as shown in Figure 4 Compared with the as-cast alloy, it is found that after annealing treatment at 700℃, the size of β-Ti phase is reduced, and the distribution is more uniform, and the appearance is more diverse. The dispersion distribution reduces the activation energy required by hydrogen atoms in the diffusion process. At 800℃, the size and quantity of the secondary phase do not change obviously, but the distribution is more uniform, which is more conducive to hydrogen absorption. At 1100℃, it is found that the secondary phase begins to present directional distribution along a certain angle, the content of the secondary phase is slightly reduced compared with the as-cast alloy, and some black phase precipitates appear.

[0033] In view of this, the inventors of the present invention believe that it is feasible to heat the TiFe-based hydrogen storage material with the alloy component at 700-1100°C for 6 hours and then furnace cool it to activate its hydrogen absorption performance. Particularly preferably, the temperature range is 800-1100°C. Example

[0034] Except for the different ingredients, the remaining steps were the same as described in Example 1 to prepare TiFe 0.8 Mn 0.2 alloy. Figure 5 The TiFe alloy was heated at 700℃, 800℃, and 1100℃, kept at this temperature for 6 hours, and then cooled in the furnace. 0.8 Mn 0.2 Backscattered electron micrograph of the alloy.

[0035] and Figure 4 By comparison, it can be seen that the increase in Mn content has led to a significant change in the phase composition of the alloy, with three main phases: gray matrix phase (TiFe phase), dark gray phase (β-Ti phase), and white phase (TiFe2 phase). Compared with the as-cast alloy, annealing at 700°C only found a decrease in the content of the white phase, and the morphology of the as-cast alloy did not change much. Annealing at 800°C found that the size of the white phase was significantly enlarged, and the morphology of the white phase changed. Annealing at 1100°C found that the size of the precipitated phase (mainly the white phase) was significantly reduced and dispersed evenly in the gray matrix, which provided it with a large number of dislocations and defects, and increased the surface area.

[0036] Figure 6 The TiFe 0.8 Mn 0.1 Alloy and TiFe in Example 3 0.8 Mn 0.2 Backscattered electron micrographs of alloys heated at 700°C, 800°C, and 1100°C, held for 6 hours, and then furnace-cooled (a) (b) 700°C (c) 800°C (d) 1100°C). Due to the superstoichiometric composition, a large amount of dark gray phase (β-Ti phase) is observed. This phase is a hydrogen-absorbing phase, providing sites for hydrogenation of the TiFe phase. However, excessive amounts of this phase can lead to decreased cyclic hydrogen storage performance. Segregation is severe in the as-cast alloy, and the proportion of the dark gray phase is too high. Annealing at 700°C reveals segregation and uneven distribution of the dark gray phase. Annealing at 800°C significantly reduces the amount of the dark gray phase, reduces its size, and makes its distribution more uniform. Annealing at 1100°C reveals a more uniform distribution of the secondary phase at this temperature, likely due to the enhanced atomic mobility and diffusion at this higher temperature. Numerous isolated dark gray precipitates appear.

[0037] The alloy was heated at 700℃, 800℃, 1100℃, and held for 6h, then furnace-cooled, as shown in Figure 5 Due to the super-stoichiometric composition, a large amount of dark gray phase (β-Ti phase) can be found, which is a hydrogen absorption phase and provides sites for hydrogenation of TiFe phase, but too much phase content will lead to a decrease in cyclic hydrogen storage performance. The as-cast alloy has serious segregation, and the proportion of dark gray phase is too high. Annealing at 700℃, it is found that the dark gray phase is segregated and unevenly distributed. Annealing at 800℃, it is found that the content of dark gray phase is significantly reduced, and the phase size is reduced and more evenly distributed.

[0038] Annealing at 1100℃, it is found that the secondary phase is more evenly distributed at this temperature, which may be due to the higher temperature, the activity of atoms is enhanced, and the diffusion is more sufficient, and there are many isolated dark gray precipitated particles.

[0039] Therefore, in summary, in order to improve the hydrogen absorption activity of TiFe-based hydrogen absorption material, annealing the alloy at 800-1100℃ is an effective method.

[0040] The area of different phases in the scanning image is calculated by image J software to approximate the volume fraction of different phases. It is found that the volume fraction of the matrix phase in TiFe 0.8 Mn 0.1 , TiFe 0.8 Mn 0.2 alloy is higher, and the content of precipitated phase decreases and the size decreases, which can improve the hydrogen absorption capacity and activation performance of the alloy. Therefore, the alloy is selected for hydrogen absorption test at this temperature.

[0041] Further, as shown in the hydrogen absorption performance test results, Figure 6-8 after holding at 700℃ for 6h, the alloy can be completely activated without incubation period, and the hydrogen absorption rate of TiFe 0.8 Mn 0.1 alloy is faster. Since the alloy contains β-Ti solid solution, it first absorbs hydrogen during activation, providing a large number of activation sites for the alloy and improving the activation performance.

[0042] It is found that as the temperature decreases, the hydrogen absorption capacity of the alloy increases. And the hydrogen absorption rate is fast, and it is saturated in 80min. The hydrogen absorption performance at room temperature is poor, and the hydrogen absorption rate is slow. The hydrogen absorption rate is faster at 25℃ and 40℃, and the maximum hydrogen absorption capacity can reach 1.82wt.%, close to the theoretical hydrogen absorption capacity of the alloy.

[0043] Therefore, according to the examples 2 and 3, the feedback of the micro-observation of the phase composition and the selection of the hydrogen absorption amount in practice are considered, and the TiFe-based hydrogen storage material is preferably activated at 700-1100°C for 6h. On the basis of the determination of the main components in the preferred TiFe alloy, examples 4-7 are further designed to further improve the activity performance and hydrogen absorption capacity by adding adjusting components. Example

[0044] Step one: alloy ingot melting According to the TiFe 0.8 Mn 0.1 Nb 0.1 Zr 0.05 alloy composition stoichiometric ratio, wherein for Mn, considering the loss on ignition and volatilization, 5wt.% of Mn is added based on the calculated mass, and the purity of the raw material is greater than 99.5%, and the total mass is 50g, then vacuum arc furnace is used for melting, low vacuum is first extracted, the pressure gauge is below-0.1MPa, then argon is filled, and the pressure gauge is stopped when the pressure gauge reaches-0.05MPa. Repeat the gas washing 3~4 times. The current is controlled below 350A during the melting process to prevent the volatilization of Mn element, and the melting is repeated 4~5 times to make TiFe 0.8 Mn 0.1 Nb 0.1 Zr 0.05 alloy.

[0045] Step two: heat treatment and ball milling for activation The melted TiFe 0.8 Mn 0.1 Nb 0.1 Zr 0.05 alloy is placed into a vacuum hot pressing furnace, the vacuum degree is 1×10 -4 Pa, heated to 1100°C for 2h, then heat treated for 6h and cooled in the furnace. Then the heat treated TiFe 0.8 Mn 0.1 Nb 0.1 Zr 0.05 alloy is mechanically broken, then ground in a corundum mortar to make a powder, and sieved through a 100 mesh sieve, the sieved powder is placed into a high-energy ball mill, the ball-to-material ratio in the ball mill jar is 10∶1, the rotation speed is 865r / min, and the ball milling is performed for 3h, then the TiFe 0.8 Mn 0.1 Nb 0.1 Zr 0.05 hydrogen storage alloy powder is obtained. Example

[0046] Step one: alloy ingot melting According to TiFe 0.8 Mn 0.1 Nb 0.05 Zr 0.05 Y 0.05 alloy ingredients stoichiometric ratio, add 5wt.% of Mn, the purity of raw materials is greater than 99.5%, the total mass is 50g, then adopt vacuum arc furnace to smelt, first low vacuum, the pressure table reaches below -0.1MPa, then fill argon, stop filling argon when the pressure table reaches -0.05MPa. Repeat gas washing 3~4 times. The current control is below 350A in the smelting process to prevent Mn element volatilization, repeat 4~5 times to make smelting uniform, and TiFe 0.8 Mn 0.1 Nb 0.05 Zr 0.05 Y 0.05 alloy is prepared.

[0047] Step two: heat treatment and ball milling treatment are activated The TiFe 0.8 Mn 0.1 Nb 0.05 Zr 0.05 Y 0.05 alloy is mechanically broken, then ground in corundum mortar to prepare powder, screen through 100 mesh sieve, and the screened powder is put into high-energy ball mill, the ball-to-material ratio in the ball mill tank is 10∶1, the rotating speed is 865r / min, ball milling is carried out for 3h, and then TiFe 0.8 Mn 0.1 Nb 0.05 Zr 0.05 Y 0.05 hydrogen storage alloy powder is obtained. Example

[0048] Step one: smelting alloy ingot According to Ti 1.2 Fe 0.8 Mn 0.2 Nb 0.1 alloy ingredients stoichiometric ratio, add 5wt.% of Mn, the purity of raw materials is greater than 99.5%, the total mass is 50g, then adopt vacuum arc furnace to smelt, first low vacuum, the pressure table reaches below -0.1MPa, then fill argon, stop filling argon when the pressure table reaches -0.05MPa. Repeat gas washing 3~4 times. The current control is below 350A in the smelting process to prevent Mn element volatilization, repeat 4~5 times to make smelting uniform, and Ti 1.2 Fe 0.8 Mn 0.2 Nb 0.1 alloy is prepared.

[0049] Step two: activation by heat treatment and ball milling The melted TiFe 1.2 Fe 0.8 Mn 0.2 Nb 0.1 alloy was mechanically broken, and then ground in an agate mortar to form a powder, which was sieved through a 100 mesh sieve. The sieved powder was placed in a high-energy ball mill, with a ball-to-powder ratio of 10:1, and a rotation speed of 865 r / min. The alloy was ball-milled for 3 h, and then a Ti1.2Fe0.8Mn0.2 hydrogen storage alloy powder was obtained. Example

[0050] The only difference between Example 4 and Example 5 is that the melted TiFe 0.8 Mn 0.1 Nb 0.1 Zr 0.05 alloy was placed in a vacuum hot-pressing furnace, with a vacuum degree of 1 x 10 -4 Pa, heated to 1100°C for 2 h, and then held for 6 h and cooled in the furnace. The remaining steps were the same as in Example 4. Results analysis The hydrogen absorption performance test results of Example 4 are shown in Figure 9 (a). The alloy was completely activated after only two cycles of hydrogen absorption and desorption. Subsequently, hydrogen absorption kinetics tests were performed at 70°C, 55°C, 40°C, 25°C, and 4 MPa H2, as shown in Figure 10 (a). As the temperature decreased, the hydrogen absorption amount of the alloy increased. Since the hydrogen absorption reaction is an exothermic reaction, the lower the temperature, the higher the hydrogen absorption reaction trend. The hydrogen absorption rate was the fastest at 40°C, and the hydrogen absorption amount was high (1.6 wt.%). The maximum hydrogen absorption amount at room temperature was 1.82 wt.%.

[0051] The hydrogen absorption performance test results of Example 5 are shown in Figure 9 (b). The alloy absorbed hydrogen directly without an incubation period after 80 min of hydrogen absorption at 300°C and 4 MPa H2. The alloy was completely activated after two cycles of hydrogen absorption and desorption. Subsequently, hydrogen absorption kinetics tests were performed at 70°C, 55°C, 40°C, 25°C, and 4 MPa H2, as shown in Figure 10 (b). The hydrogen storage amount at room temperature could reach 1.95 wt.%. The inventors of the present application believe that this is because the volume fraction of the main hydrogen absorption phase in the alloy is the highest, and the addition of each additive element causes lattice expansion, which to some extent improves the hydrogen absorption amount of the alloy. As the temperature decreased, the hydrogen absorption amount of the alloy increased, and the hydrogen absorption rate increased. The alloy had good room-temperature hydrogen absorption performance.

[0052] The hydrogen absorption performance test results of Example 6 are shown in Figure 9(c) shows that the hydrogen absorption is 80 min at 300℃ and 4 MPa H2, without incubation period, and the hydrogen absorption amount is high, reaching 90% of the saturated hydrogen absorption in the first hydrogen absorption. Subsequently, the hydrogen absorption kinetics test is carried out at 70℃, 55℃, 40℃, 25℃ and 4 MPa H2, as shown in Figure 10 (c) shows that the hydrogen storage amount at room temperature can reach 1.42 wt.%, and the hydrogen absorption amount is slightly lower than that of examples 4 and 5. The inventors of the present application believe that this is because the volume fraction of the main hydrogen absorption phase TiFe phase in the alloy is lower than that of the previous two, and the number of secondary phases is more. After the first hydrogen absorption, it exists in the alloy in the form of hydride, which is difficult to dehydrogenate, resulting in a slight decrease in hydrogen absorption in the subsequent test, but the overall performance is still excellent.

[0053] Example 7 prepares the same alloy composition as example 4, and heat treatment is carried out. The hydrogen absorption kinetics test of TiFe 0.8 Mn 0.1 Nb 0.1 Zr 0.05 The alloy is activated and hydrogen absorption test, and the hydrogen absorption performance test results are as shown in Figure 11 It is found that the alloy can directly absorb hydrogen without activation, and the hydrogen absorption amount is close to the theoretical hydrogen storage amount of the alloy, reaching 1.7 wt.% within 5 min, with excellent hydrogen absorption performance, as shown in Figure 11 . The basic principles of the present disclosure are described above in combination with specific examples, but it should be noted that the advantages, advantages, effects and the like mentioned in the present disclosure are only examples and cannot be considered as the must-have of each embodiment of the present disclosure. In addition, the specific details of the above disclosure are only for the purpose of example and for the purpose of understanding, and the above details do not limit the present disclosure to the above specific details.

[0054] The block diagram of the device, apparatus, equipment, system involved in the present disclosure is only an illustrative example and is not intended to require or imply the connection, arrangement, configuration shown in the block diagram. As those skilled in the art will recognize, these devices, apparatus, equipment, system can be connected, arranged, configured in any way. Words such as "include", "contain", "have" and the like are open-ended words, which mean "including but not limited to", and can be used interchangeably. The words "or" and "and" used herein mean the word "and / or", and can be used interchangeably unless the context clearly indicates otherwise. The word "such as" used herein means the phrase "such as but not limited to", and can be used interchangeably.

[0055] It should also be noted that in the device, equipment and method of the present disclosure, each component or each step can be decomposed and / or recombined. These decompositions and / or recombination should be considered as equivalent solutions of the present disclosure.

[0056] In this document, adjectives such as "first", "second", etc. not followed by numerals are intended to be used for distinguishing various elements / components / circuits / modules / devices / steps, and not to imply order, positional relationship, importance, priority, etc. In contrast, adjectives such as "first", "second", etc. followed by numerals can be used to emphasize order, positional relationship, importance, priority, etc. of various elements / components / circuits / modules / devices / steps.

[0057] The above description of the disclosed aspects is given to enable any person skilled in the art to make or use the disclosure. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other aspects without departing from the scope of the disclosure. Thus, the disclosure is not intended to be limited to the aspects shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0058] The above description has been given for the purpose of illustration and description. Furthermore, this description does not purport to be exhaustive or to limit the embodiments of the disclosure to the precise forms disclosed. Although various example aspects and embodiments have been discussed above, a person of ordinary skill in the art will recognize certain variations, modifications, changes, additions, and sub-combinations thereof.

Claims

1. A Ti-Fe based hydrogen storage material, characterized in that The hydrogen storage material also contains Mn and Nb elements, and its alloy composition is Ti x Fe y Mn z Nb a , where x, y, z, and a are atomic ratios, 1.0≤x≤1.2, 0.8≤y≤0.9, 0.1≤z≤0.2, and 0.01≤a≤0.

2.

2. The Ti-Fe based hydrogen storage material according to claim 1, characterized in that The hydrogen storage material also contains Zr element, and its alloy composition is Ti x Fe y Mn z Nb a Zr b , where x, y, z, a, and b are atomic ratios, 1.0≤x≤1.1, 0.8≤y≤0.9, 0.1≤z≤0.2, 0.05≤a≤0.2, and 0.05≤b≤0.

2.

3. The Ti-Fe based hydrogen storage material according to claim 2, characterized in that The hydrogen storage material also contains Y element, and its alloy composition is Ti x Fe y Mn z Nb a Zr b Y c , where x, y, z, a, b, and c are atomic ratios, 1.0≤x≤1.1, 0.80≤y≤0.85, 0.1≤z≤0.2, 0.05≤a≤0.15, 0.05≤b≤0.15, and 0.05≤c≤0.

15.

4. The Ti-Fe based hydrogen storage material according to claim 2, characterized in that The hydrogen storage material alloy is composed of TiFe 0.8 Mn 0.1 Nb 0.1 Zr 0.05 、TiFe 0.8 Mn 0.1 Nb 0.05 Zr 0.05 Y 0.05 、TiFe 0.8 Mn 0.2 Nb 0.05 Zr 0.05 Y 0.05 、TiFe 0.8 Mn 0.2 Nb 0.15 Zr 0.05 Y 0.05 Any one of the groups consisting of, wherein each subscript number is an atomic ratio.

5. The Ti-Fe based hydrogen storage material according to claim 1, characterized in that The hydrogen storage material alloy composition is TiFe 0.8 Mn 0.1 Nb 0.05 Zr 0.05 Y 0.05 、TiFe 0.8 Mn 0.2 Nb 0.05 Zr 0.05 Y 0.05 、TiFe 0.8 Mn 0.2 Nb 0.15 Zr 0.05 Y 0.05 Any one of the groups consisting of, wherein each subscript number is an atomic ratio.

6. A method for activating the Ti-Fe based hydrogen storage material according to any one of claims 1 to 5, characterized in that: The steps include: (1) Preparation process of hydrogen storage materials The ingredients are prepared according to the elemental composition of the alloy, and 5 wt.% Mn is additionally added based on the calculated required Mn element content; Place the prepared material in a copper crucible of an electric arc furnace, evacuate and fill with argon, cycle 3-4 times, and then start smelting; During the smelting process, the ingot was repeatedly turned over four times, each smelting time was 3-5 minutes, the current did not exceed 350A, and after the smelting was completed, the sample was taken out after cooling in the arc furnace for 20 minutes; (2) Heat treatment process of hydrogen storage materials After obtaining the ingot of the hydrogen storage material, the ingot is heat-treated in a vacuum hot pressing furnace, heated to 700-1100° C. at a heating rate not exceeding 10° / min, kept at this temperature for 6 hours, and then cooled with the furnace; (3) Ball milling process of hydrogen storage materials The heat-treated ingot was linearly cut into small samples, which were then mechanically crushed and sieved through a 100-mesh sieve. The sieved particles were ball-milled in a high-energy ball mill for 3 hours to obtain alloy powder.

7. The activation method according to claim 6, characterized in that The ball-to-material ratio is 10~15:1, the rotation speed is 700~800r / min, the ball milling time is 3-4h, and the ball milling process is cooled for 10min every 30min.

8. The activation method according to claim 7, characterized in that The average size of the hydrogen storage material alloy powder after ball milling should be between 40-50 μm, and the purity of each raw material of the hydrogen storage material should be above 99.5%.

9. The activation method according to claim 8, characterized in that The current during the arc furnace melting process is between 200-350A, and the vacuum degree should be controlled at 5×10 -3 Below Pa.

10. The activation method according to claim 9, characterized in that The heat treatment process of the hydrogen storage material is to heat to 1100° C. for 2 hours, then keep the temperature for 6 hours and cool with the furnace. The hydrogen storage material after the activation treatment can store 1.7 wt.% of hydrogen within 5 minutes.

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