Ti-based hydrogen storage alloy with trace V replacing different sites and preparation method of Ti-based hydrogen storage alloy

Abstract

The invention discloses a Ti-based hydrogen storage alloy with trace V replacing different sites and a preparation method of the Ti-based hydrogen storage alloy, and belongs to the technical field of solid hydrogen storage materials and preparation of the solid hydrogen storage materials. The problems that an existing Ti-based AB2 type hydrogen storage alloy is high in activation condition, high in hydrogen absorption and desorption platform pressure, large in lag, low in cycling stability and the like are solved. According to the invention, V is adopted to selectively replace A-side Ti or B-side Cr of the Ti-based AB2 type hydrogen storage alloy, and when V is adopted to replace B-side Cr, lattice expansion is caused, so that the hydrogen storage capacity of the alloy can be synergistically improved, the pressure of a hydrogen absorption and desorption platform can be reduced, hydrogen absorption kinetics can be accelerated, and the cycle stability can be improved; when V is used for replacing Ti on the A side, lattice shrinkage is caused, the performance improvement effect is different, directional triple regulation and control over the alloy performance are achieved by controlling the replacement site of V, and a new component design thought and theoretical basis are provided for developing a high-performance and long-life hydrogen storage material.

Description

Technical Field

[0001] This invention relates to a Ti-based hydrogen storage alloy with trace amounts of V replacing different sites and its preparation method, belonging to the field of solid hydrogen storage materials and their preparation technology. Background Technology

[0002] Hydrogen energy is considered an ideal clean energy carrier due to its high energy density and environmental friendliness. However, safe, efficient, and economical hydrogen storage technology remains a bottleneck for its large-scale application. Solid-state hydrogen storage utilizes metal hydrides to reversibly absorb and release hydrogen, offering advantages such as high volumetric hydrogen storage density and good safety. Among these, Ti-Zr-Cr-Mn based alloys have attracted considerable attention due to their suitable operating conditions, high hydrogen storage capacity, and good kinetic performance.

[0003] However, traditional Ti-based AB2-type hydrogen storage alloys suffer from problems in practical applications, such as high activation conditions, high plateau pressures for hydrogen absorption and desorption (exceeding 2 MPa at room temperature), large hysteresis, and low cycle stability. In order to improve alloy performance, it is essential to provide an alloy material that combines high hydrogen storage capacity, excellent kinetic performance, and long cycle life. Summary of the Invention

[0004] To address the problems of high activation requirements, high plateau pressures for hydrogen absorption and desorption, significant hysteresis, and low cycle stability in existing Ti-based AB2-type hydrogen storage alloys, this invention provides a Ti-based hydrogen storage alloy with trace V substitution at different sites and its preparation method.

[0005] The technical solution of the present invention: One objective of this invention is to provide a Ti-based hydrogen storage alloy, comprising Ti 0.84 Zr 0.22 Cr 1.24 Mn 0.7 Or use trace amounts of V to replace Ti 0.84 Zr 0.22 Cr 1.24 Mn 0.7 Ti or Cr.

[0006] Further specifying, the structural formula is: Ti 0.84-x Zr 0.22 Cr 1.24 Mn 0.7 V x or Ti 0.84 Zr 0.22 Cr 1.24-y Mn 0.7 V y , 0≤x≤0.05, 0≤y≤0.1.

[0007] Further specifying, the structural formula of the Ti-based hydrogen storage alloy is Ti0.84 Zr 0.22 Cr 1.14 Mn 0.7 V 0.1 .

[0008] Further specifying, the structural formula of the Ti-based hydrogen storage alloy is Ti 0.79 Zr 0.22 Cr 1.24 Mn 0.7 V 0.05 .

[0009] Further specifying, the Ti-based hydrogen storage alloy is an AB2 type alloy with a single-phase structure of C14-type Laves phase.

[0010] A second objective of this invention is to provide a method for preparing the above-mentioned Ti-based hydrogen storage alloy, the method comprising the following steps: (1) Weigh out Ti, Zr, Cr, Mn and V metal elements with a purity greater than 99% according to the atomic ratio of the structural formula, mix them evenly to obtain the raw materials; (2) The uniformly mixed raw materials are melted multiple times in an argon atmosphere using an electric arc melting method; (3) After melting, the crucible is cooled to room temperature to obtain Ti-based hydrogen storage alloy.

[0011] Further specified, (1) is in 5% excess of the elemental Mn metal.

[0012] Further specifying, in (2) the smelting current is 90. 120A.

[0013] Further specifying, in (2) the smelting gas pressure is 1×10 3 Below Pa.

[0014] Further, (2) requires smelting more than 6 times.

[0015] Beneficial effects: This invention reveals the triple (structure-thermodynamics-kinetics) synergistic regulation of the substitution sites of trace amounts of V (Ti on the A side or Cr on the B side) on the alloy's crystal structure, thermodynamics, kinetics, and cycle stability by precisely controlling these substitution sites. This results in an alloy material possessing high hydrogen storage capacity, excellent kinetic performance, and long cycle life. In particular, V substitution for Cr on the B side simultaneously achieves increased capacity, reduced plateau pressure, accelerated kinetics, and extended cycle life. Compared with existing technologies, it has at least the following advantages: (1) The Ti-based hydrogen storage alloy prepared by the present invention reaches the maximum hydrogen absorption capacity of 95% in only 78 seconds at room temperature.

[0016] (2) Ti prepared in this invention0.84 Zr 0.22 Cr 1.14 Mn 0.7 V 0.1 The alloy achieves a maximum hydrogen storage capacity of 1.94 wt.% at 298 K. The hydrogen absorption kinetics follow the nucleation and growth mechanism and the rate is significantly faster than that of the base alloy. After 100 cycles, the capacity retention rate is as high as 98.9%, demonstrating excellent comprehensive hydrogen storage performance.

[0017] (3) The present invention uses a small amount of V as a substitute, which achieves a leapfrog improvement in performance without increasing the cost of raw materials, and is more stable and economical in terms of cost and supply chain.

[0018] (4) By controlling the occupancy of V at the A or B site, this invention reveals the differential effects of V substitution on the A and B sides of Ti-Zr-Cr-Mn alloys. V substitution of Cr on the B side causes lattice expansion, which is beneficial to improving hydrogen storage capacity, reducing plateau pressure, and accelerating hydrogen diffusion. V substitution of Ti on the A side causes lattice contraction, which does not significantly help improve capacity, but the inherent catalytic effect of V can still improve kinetics to a certain extent. This provides a clear theoretical basis for the precise design of alloy composition through site engineering.

[0019] (5) The alloy provided by the present invention is prepared by a mature electric arc melting method. The process is simple, has good repeatability, and is easy to scale up. Attached Figure Description

[0020] Figure 1 The activation curve of the hydrogen storage alloy prepared in Example 1 at 298 K and a hydrogen pressure of 5.5 MPa ± 0.1 MPa is shown. Figure 2 The activation curve of the hydrogen storage alloy prepared in Example 2 is shown at 298 K and a hydrogen pressure of 5.5 MPa ± 0.1 MPa. Figure 3 The activation curve of the hydrogen storage alloy prepared in Example 3 is shown at 298 K and a hydrogen pressure of 5.5 MPa ± 0.1 MPa. Figure 4 The hydrogen absorption kinetics curves of the hydrogen storage alloy prepared in Example 1 at 273K, 298K, 323K, and 348K, with a hydrogen pressure of 5.5MPa ± 0.1MPa are shown. Figure 5 The hydrogen absorption kinetics curves of the hydrogen storage alloy prepared in Example 2 at 273K, 298K, 323K, and 348K, with a hydrogen pressure of 5.5MPa ± 0.1MPa are shown. Figure 6 The hydrogen absorption kinetics curves of the hydrogen storage alloy prepared in Example 3 at 273K, 298K, 323K, and 348K, with a hydrogen pressure of 5.5MPa ± 0.1MPa are shown. Figure 7 The hydrogen absorption / desorption PCT curves of the hydrogen storage alloy prepared in Example 1 at 273K, 298K, 323K, and 348K, with a hydrogen pressure of 5.5MPa ± 0.1MPa; Figure 8 The hydrogen absorption / desorption PCT curves of the hydrogen storage alloy prepared in Example 2 at 273K, 298K, 323K, and 348K, with a hydrogen pressure of 5.5MPa ± 0.1MPa are shown. Figure 9 The hydrogen absorption / desorption PCT curves of the hydrogen storage alloy prepared in Example 3 at 273K, 298K, 323K, and 348K, with a hydrogen pressure of 5.5MPa ± 0.1MPa are shown. Figure 10 The hydrogen absorption performance of the hydrogen storage alloy prepared in Example 1 after 100 cycles at 323K and a hydrogen pressure of 5.5MPa±0.1MPa; Figure 11 The hydrogen absorption performance of the hydrogen storage alloy prepared in Example 2 after 100 cycles at 323K and a hydrogen pressure of 5.5MPa±0.1MPa; Figure 12 The hydrogen absorption performance of the hydrogen storage alloy prepared in Example 3 after 100 cycles at 323K and a hydrogen pressure of 5.5MPa±0.1MPa is shown. Detailed Implementation

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0022] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art may make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0023] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0024] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.

[0025] Example 1: The structural formula of the Ti-based hydrogen storage alloy provided in this comparative example is Ti. 0.84 Zr 0.22 Cr 1.24 Mn 0.7 .

[0026] The above structural formula is Ti 0.84 Zr 0.22 Cr 1.24 Mn 0.7 The method for preparing the hydrogen storage alloy includes the following steps: Weigh each metal raw material according to the atomic ratio Ti:Zr:Cr:Mn=0.84:0.22:1.24:0.7. All raw materials are elemental Ti, Zr, Cr and Mn with a purity higher than 99wt.%, with Mn in excess by 5% to compensate for losses during the smelting process.

[0027] The raw materials were placed in a water-cooled copper crucible and smelted under the protection of high-purity argon gas, with a smelting current of 90 Ω. Within the 120A range, the alloy is melted and cooled to 298K to form an alloy ingot. To ensure uniform composition, the alloy ingot is flipped and remelted six times. The resulting ingot is mechanically crushed, ground, and sieved to obtain 100-400 mesh powder for testing.

[0028] Weigh approximately 1.5g of hydrogen storage alloy powder and place it into the reactor of a Sievert's PCT tester for pretreatment: evacuate to 1×10⁻⁶. 4 Below MPa, the temperature was increased from 298K to 623K within 0.5h, then maintained at 623K for 1h, and finally cooled to 298K. Activation at 298K was then performed: approximately 5.5MPa of 99.999% pure hydrogen gas was introduced, and the sample underwent initial hydrogen absorption activation at 298K. Afterwards, the hydrogen gas was purged, and the sample was cooled to 298K. This activation process was repeated once more to verify complete activation. The activation curve is shown below. Figure 1 Then, the hydrogen absorption kinetics were tested at 273K, 298K, 323K, and 348K. The test at 273K was conducted in a cryogenic chamber, and the results are as follows: Figure 4 As shown in the figure. Then, the hydrogen absorption / desorption PCT curves were tested at temperatures of 273K, 298K, 323K, and 348K, and a hydrogen pressure of 5.5MPa ± 0.1MPa. The results are shown in the figure. Figure 7As shown. Finally, cycle stability tests were performed: at 323 K, the 1st, 25th, 50th, 75th, and 100th cycles were conducted under a hydrogen pressure of 5.5 MPa and a hydrogen uptake time of 0.5 h, followed by dehydrogenation at 623 K for 1.5 h. The 2nd-24th, 26th-49th, 51st-74th, and 76th-99th cycles were conducted under a hydrogen pressure of 3.0 MPa and a hydrogen uptake time of 0.1 h, followed by dehydrogenation at 1 × 10⁻⁶ K. -4 Dehydrogenation was performed under a vacuum pressure of MPa, and the cycle retention results are as follows: Figure 10 .

[0029] analyze Figure 1 , 4 As can be seen from 7 and 10, the Ti prepared in Example 1 0.84 Zr 0.22 Cr 1.24 Mn 0.7 The hydrogen storage alloy can absorb hydrogen upon activation at 298 K. The maximum hydrogen absorption capacity is 1.89 wt.% at 273 K, with a reversible hydrogen storage capacity of 1.79 wt.%. At 298 K, the maximum hydrogen absorption capacity is 1.82 wt.%, with a reversible hydrogen storage capacity of 1.75 wt.%. At 323 K, the maximum hydrogen absorption capacity is 1.74 wt.%, with a reversible hydrogen storage capacity of 1.70 wt.%. The hydrogen absorption plateau pressures at 273 K, 298 K, and 323 K are 0.36 MPa, 0.81 MPa, and 1.67 MPa, respectively, with plateau slopes of 1.14, 1.01, and 0.97, and hysteresis coefficients of 0.26, 0.11, and 0.06, respectively. After 100 hydrogen absorption / desorption cycles, the capacity retention is 93.3%.

[0030] Example 2: The structural formula of the Ti-based hydrogen storage alloy with trace V substitution provided in this embodiment is Ti. 0.84 Zr 0.22 Cr 1.14 Mn 0.7 V 0.1 .

[0031] The above structural formula is Ti 0.84 Zr 0.22 Cr 1.14 Mn 0.7 V 0.1 The method for preparing the hydrogen storage alloy includes the following steps: Weigh out each metal raw material according to the atomic ratio Ti:Zr:Cr:Mn:V = 0.84:0.22:1.14:0.7:0.1. All raw materials are elemental Ti, Zr, Cr, Mn and V with a purity higher than 99 wt.%, with Mn in excess by 5% to compensate for losses during the smelting process.

[0032] The raw materials were placed in a water-cooled copper crucible and smelted under the protection of high-purity argon gas, with a smelting current of 90 Ω. Within the 120A range, the alloy is melted and cooled to 298K to form an alloy ingot. To ensure uniform composition, the alloy ingot is flipped and remelted six times. The resulting ingot is mechanically crushed, ground, and sieved to obtain 100-400 mesh powder for testing.

[0033] Weigh approximately 1.5g of hydrogen storage alloy powder and place it into the reactor of a Sievert's PCT tester for pretreatment: evacuate to 1×10⁻⁶. 4 Below MPa, the temperature was increased from 298K to 623K within 0.5h, then maintained at 623K for 1h, and finally cooled to 298K. Activation at 298K was then performed: approximately 5.5MPa of 99.999% pure hydrogen gas was introduced, and the sample underwent initial hydrogen absorption activation at 298K. Afterwards, the hydrogen gas was purged, and the sample was cooled to 298K. This activation process was repeated once more to verify complete activation. The activation curve is shown below. Figure 2 Then, the hydrogen absorption kinetics were tested at 273K, 298K, 323K, and 348K. The test at 273K was conducted in a cryogenic chamber, and the results are as follows. Figure 5 As shown in the figure. The hydrogen absorption / desorption PCT curves were tested at temperatures of 273K, 298K, 323K, and 348K, and a hydrogen pressure of 5.5MPa ± 0.1MPa. The results are as follows. Figure 8 As shown. Finally, cycle stability tests were performed: at 323 K, the 1st, 25th, 50th, 75th, and 100th cycles were conducted under a hydrogen pressure of 5.5 MPa and a hydrogen uptake time of 0.5 h, followed by dehydrogenation at 623 K for 1.5 h. The 2nd-24th, 26th-49th, 51st-74th, and 76th-99th cycles were conducted under a hydrogen pressure of 3.0 MPa and a hydrogen uptake time of 0.1 h, followed by dehydrogenation at 1 × 10⁻⁶ K. -4 Dehydrogenation was performed under a vacuum pressure of MPa, and the cycle retention results are as follows: Figure 11 .

[0034] analyze Figure 2 , 5 As can be seen from 8 and 11, the Ti prepared in Example 2 0.84 Zr 0.22 Cr 1.14 Mn 0.7 V 0.1The hydrogen storage alloy can absorb hydrogen upon activation at 298 K. The maximum hydrogen absorption capacity is 1.95 wt.% at 273 K, with a reversible hydrogen storage capacity of 1.81 wt.%. At 298 K, the maximum hydrogen absorption capacity is 1.94 wt.%, with a reversible hydrogen storage capacity of 1.80 wt.%. At 323 K, the maximum hydrogen absorption capacity is 1.81 wt.%, with a reversible hydrogen storage capacity of 1.72 wt.%. The hydrogen absorption plateau pressures at 273 K, 298 K, and 323 K are 0.18 MPa, 0.37 MPa, and 0.99 MPa, respectively, with plateau slopes of 0.92, 0.92, and 0.95, and hysteresis coefficients of 0.11, 0.09, and 0.04, respectively. The capacity retention rate is 98.9% after 100 hydrogen absorption / desorption cycles.

[0035] Example 3: The structural formula of the Ti-based hydrogen storage alloy with trace V substitution provided in this embodiment is Ti. 0.79 Zr 0.22 Cr 1.24 Mn 0.7 V 0.05 .

[0036] The above structural formula is Ti 0.79 Zr 0.22 Cr 1.24 Mn 0.7 V 0.05 The method for preparing the hydrogen storage alloy includes the following steps: Weigh each metal raw material according to the atomic ratio Ti:Zr:Cr:Mn:V = 0.79:0.22:1.24:0.7:0.05. All raw materials are elemental Ti, Zr, Cr, Mn and V with a purity higher than 99 wt.%, with Mn in excess by 5% to compensate for losses during the smelting process.

[0037] The raw materials were placed in a water-cooled copper crucible and smelted under the protection of high-purity argon gas, with a smelting current of 90 Ω. Within the 120A range, the alloy is melted and cooled to 298K to form an alloy ingot. To ensure uniform composition, the alloy ingot is flipped and remelted six times. The resulting ingot is mechanically crushed, ground, and sieved to obtain 100-400 mesh powder for testing.

[0038] Weigh approximately 1.5g of hydrogen storage alloy powder and place it into the reactor of a Sievert's PCT tester for pretreatment: evacuate to 1×10⁻⁶. 4Below MPa, the temperature was increased from 298K to 623K within 0.5h, then maintained at 623K for 1h, and finally cooled to 298K. Activation at 298K was then performed: approximately 5.5MPa of 99.999% pure hydrogen gas was introduced, and the sample underwent initial hydrogen absorption activation at 298K. Afterwards, the hydrogen gas was purged, and the sample was cooled to 298K. This activation process was repeated once more to verify complete activation. The activation curve is shown below. Figure 3 Then, the hydrogen absorption kinetics were tested at 273K, 298K, 323K, and 348K. The test at 273K was conducted in a cryogenic chamber, and the results are as follows. Figure 6 As shown in the figure. The hydrogen absorption / desorption PCT curves were tested at temperatures of 273K, 298K, 323K, and 348K, and a hydrogen pressure of 5.5MPa ± 0.1MPa. The results are as follows. Figure 9 As shown. Finally, cycle stability tests were performed: at 323 K, the 1st, 25th, 50th, 75th, and 100th cycles were conducted under a hydrogen pressure of 5.5 MPa and a hydrogen uptake time of 0.5 h, followed by dehydrogenation at 623 K for 1.5 h. The 2nd-24th, 26th-49th, 51st-74th, and 76th-99th cycles were conducted under a hydrogen pressure of 3.0 MPa and a hydrogen uptake time of 0.1 h, followed by dehydrogenation at 1 × 10⁻⁶ K. -4 Dehydrogenation was performed under a vacuum pressure of MPa, and the cycle retention results are as follows: Figure 12 .

[0039] analyze Figure 3 , 6 As can be seen from 9 and 12, the Ti prepared in Example 3 0.79 Zr 0.22 Cr 1.24 Mn 0.7 V 0.05 The hydrogen storage alloy can absorb hydrogen upon activation at 298 K. The maximum hydrogen absorption capacity is 1.88 wt.% at 273 K, with a reversible hydrogen storage capacity of 1.79 wt.%. At 298 K, the maximum hydrogen absorption capacity is 1.78 wt.%, with a reversible hydrogen storage capacity of 1.73 wt.%. At 323 K, the maximum hydrogen absorption capacity is 1.65 wt.%, with a reversible hydrogen storage capacity of 1.58 wt.%. The hydrogen absorption plateau pressures at 273 K, 298 K, and 323 K are 0.50 MPa, 1.16 MPa, and 1.90 MPa, respectively, with plateau slopes of 0.95, 0.97, and 0.96, and hysteresis coefficients of 0.24, 0.12, and 0.07, respectively. After 100 hydrogen absorption / desorption cycles, the capacity retention is 96.0%.

[0040] The above description is only a preferred embodiment of the present invention. Given that those skilled in the art can make appropriate changes and modifications to the above embodiments, the present invention is not limited to the specific embodiments described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention.

Claims

1. A Ti-based hydrogen storage alloy, characterized in that, Including Ti 0.84 Zr 0.22 Cr 1.24 Mn 0.7 Or use trace amounts of V to replace Ti 0.84 Zr 0.22 Cr 1.24 Mn 0.7 Ti or Cr.

2. The Ti-based hydrogen storage alloy according to claim 1, characterized in that its structural formula is: Ti 0.84-x Zr 0.22 Cr 1.24 Mn 0.7 V x or Ti 0.84 Zr 0.22 Cr 1.24-y Mn 0.7 V y , 0≤x≤0.05, 0≤y≤0.

1.

3. The Ti-based hydrogen storage alloy according to claim 1, characterized in that, The structural formula of the Ti-based hydrogen storage alloy is Ti. 0.84 Zr 0.22 Cr 1.14 Mn 0.7 V 0.1 .

4. The Ti-based hydrogen storage alloy according to claim 1, characterized in that, The structural formula of the Ti-based hydrogen storage alloy is Ti. 0.79 Zr 0.22 Cr 1.24 Mn 0.7 V 0.05 .

5. The Ti-based hydrogen storage alloy according to claim 1, characterized in that, Ti-based hydrogen storage alloys are AB2 type alloys with a single-phase structure of C14-type Laves phase.

6. A method for preparing a Ti-based hydrogen storage alloy according to any one of claims 1 to 5, characterized in that, include: (1) Weigh out Ti, Zr, Cr, Mn and V metal elements with a purity greater than 99% according to the atomic ratio of the structural formula, mix them evenly to obtain the raw materials; (2) The uniformly mixed raw materials are melted multiple times in an argon atmosphere using an electric arc melting method; (3) After melting, the crucible is cooled to room temperature to obtain Ti-based hydrogen storage alloy.

7. The preparation method according to claim 6, characterized in that, (1) The mass of elemental Mn is 5% in excess.

8. The preparation method according to claim 6, characterized in that, (2) The smelting current is 90. 120A.

9. The preparation method according to claim 6, characterized in that, (2) The smelting gas pressure is 1×10 3 Below Pa.

10. The preparation method according to claim 6, characterized in that, (2) The number of smelting times is more than 6.

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