Titanium-based hydrogen storage alloy material and preparation method and application thereof

Abstract

The invention discloses a titanium-based hydrogen storage alloy material and a preparation method and application thereof. The element composition of the titanium-based hydrogen storage alloy material is Ti < 0.890 > Zr < 0.110 > Cr < 0.900 > Mn < 0.800 > Fe < 0.175 > (VFe) < 0.125 > + x wt.% Ce, and x ranges from 0 to 5. The titanium-based hydrogen storage alloy material has the characteristics of being easy to activate and excellent in hydrogen absorption and desorption performance (suitable in hydrogen absorption and desorption platform pressure, small in platform lag, large in reversible hydrogen storage capacity and fast in hydrogen absorption and desorption dynamics), and can meet the application conditions of kilowatt-level fuel cells of heavy machinery; the practical application of the Ti-based AB2 type hydrogen storage alloy in the aspect of kilowatt-level fuel cells is favorably widened.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen storage materials, and particularly relates to a titanium-based hydrogen storage alloy material, a preparation method thereof, and an application thereof. Background Art

[0002] Hydrogen is an excellent energy carrier and can be an excellent substitute for traditional fossil fuels. To accelerate the practical application of hydrogen energy, it is urgent to solve the problems of hydrogen storage and transportation. Among all hydrogen storage and transportation methods, solid-state hydrogen storage is the most volume-efficient and safest storage method.

[0003] As a solid-state hydrogen storage material, the Ti-based AB2-type hydrogen storage alloy has the advantages of mild hydrogen absorption and desorption conditions and good cyclic reversibility, but it also has the disadvantages of low mass hydrogen storage density and high alloy raw material cost. To reduce the adverse effects brought by the low mass hydrogen storage density of the Ti-based hydrogen storage alloy, it is considered to apply the Ti-based AB2-type hydrogen storage alloy to the kilowatt-level fuel cells of heavy machinery (such as heavy trucks, dump trucks, and forklifts, etc.). However, the hydrogen absorption and desorption platform pressures of the existing Ti-based AB2-type hydrogen storage alloys do not match, the platform hysteresis is large, the platform slope is large, and the activation performance is poor, making it difficult to meet the application conditions of such heavy machinery. In addition, the problem of high raw material cost of such alloys still exists, which severely restricts the practical application and popularization of such materials. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a titanium-based hydrogen storage alloy material with excellent hydrogen absorption and desorption performance (suitable hydrogen absorption and desorption platform pressure, small platform hysteresis, large reversible hydrogen storage capacity, and fast hydrogen absorption and desorption kinetics).

[0005] The present invention is realized through the following technical solutions:

[0006] A titanium-based hydrogen storage alloy material, whose elemental composition is Ti 0.890 Zr 0.110 Cr 0.900 Mn 0.800 Fe 0.175 (VFe) 0.125 +x wt.% Ce, where x is 0 to 5.

[0007] The Ti 0.890 Zr 0.110 Cr 0.900 Mn 0.800 Fe 0.175 (VFe) 0.125 +x wt.% Ce represents that the molar ratio of each element of the titanium-based hydrogen storage alloy material is Ti:Zr:Cr:Mn:Fe:(VFe) = 0.890:0.110:0.900:0.800:0.175:0.125, and the mass percentage content of Ce is x%.

[0008] When x is 0, the titanium-based hydrogen storage alloy material has a single-phase structure of C14 Laves phase; when x is 1 to 5, the titanium-based hydrogen storage alloy material has a two-phase structure with the C14 Laves phase as the main phase and the CeO2 phase as the second phase.

[0009] Preferably, x is 1 to 3; as a more preferred embodiment, the elemental composition of the titanium-based hydrogen storage alloy material is Ti 0.890 Zr 0.110 Cr 0.900 Mn 0.800 Fe 0.175 (VFe) 0.125 + 2 wt.% Ce.

[0010] The present invention also provides a method for preparing the titanium-based hydrogen storage alloy material, comprising the following steps:

[0011] S1. Weigh titanium, zirconium, chromium, manganese, iron, cerium elemental metals with a purity ≥ 99.9% and ferrovanadium alloy in proportion as melting raw materials, melt them in a non-consumable vacuum arc melting furnace, and obtain an alloy ingot after cooling;

[0012] S2. Grind off the oxide layer on the surface of the alloy ingot, mechanically crush it, and screen it to prepare the titanium-based hydrogen storage alloy material.

[0013] Preferably, the vacuum degree in the furnace before melting is ≤ 5.0E-5 Pa; the atmosphere in the furnace during melting is an argon atmosphere of 0.06 - 0.07 MPa. Specifically, it can be 0.06 MPa, 0.065 MPa, 0.07 MPa, etc.

[0014] Preferably, the molar ratio of vanadium to iron in the ferrovanadium alloy is 80:20.

[0015] Preferably, the melting temperature during melting is ≥ 2000 °C. The melting temperature must be high enough to ensure that the alloy is in a molten state as a whole. Since the melting points of the two phases in the alloy are different, the alloy being in a molten state as a whole can avoid macroscopic inhomogeneity of the phase structure. Further preferably, the melting temperature is 2000 - 2100 °C.

[0016] Preferably, turn over the alloy ingot obtained by melting, remelt and cool it again, repeat it multiple times, with each melting time being 1 - 2 minutes, and the number of times of turning over and remelting being not less than 5 times. Through repeated melting multiple times, the alloy ingot has high uniformity.

[0017] Preferably, grind off the surface oxide layer of the melting raw materials before melting. Since the surface of the metal raw materials may be oxidized due to long-term placement, the surface oxide layer needs to be ground off with a grinding wheel before melting until a surface with a silver-white metallic luster is exposed.

[0018] The present invention also provides the application of the titanium-based hydrogen storage alloy material in a kilowatt-level fuel cell, and specifically can be used in the kilowatt-level fuel cells of heavy machinery (such as heavy trucks, dump trucks, forklifts, etc.).

[0019] The present invention has the following beneficial effects:

[0020] The titanium-based hydrogen storage alloy material of the present invention has excellent hydrogen absorption and desorption performance (suitable hydrogen absorption and desorption platform pressure, small platform hysteresis, large reversible hydrogen storage capacity, fast hydrogen absorption and desorption kinetics). The platform at room temperature is higher than 1 atmosphere, the reversible hydrogen storage capacity at room temperature reaches 1.5 wt.%, the platform hydrogen storage capacity reaches 1.2 wt.%, the hydrogen absorption and desorption platform interval is basically between 1.5 and 3.5 MPa, and the platform slope is small, which can meet the application conditions of the kilowatt-level fuel cells of heavy machinery.

[0021] By adding a certain content of Ce, the present invention significantly improves the activation performance of the alloy material and at the same time improves its hydrogen absorption and desorption performance, obtaining a titanium-based hydrogen storage alloy material that is easy to activate and has more excellent hydrogen absorption and desorption performance. No activation treatment is required before hydrogen absorption, significantly reducing the activation cost, which is beneficial to broadening the practical application of Ti-based AB2 type hydrogen storage alloys in kilowatt-level fuel cells. Description of the Drawings

[0022] Figure 1 XRD diagrams of the titanium-based hydrogen storage alloy materials of Examples 1 to 4;

[0023] Figure 2 Backscattered electron images of the titanium-based hydrogen storage alloy materials of Examples 1 to 4;

[0024] Figure 3 First hydrogen absorption kinetic curves of the titanium-based hydrogen storage alloy materials of Examples 1 to 4 under the conditions of 25°C and 5 MPa H2;

[0025] Figure 4 Hydrogen absorption and desorption PCT (pressure - composition - isotherm) curves of the titanium-based hydrogen storage alloy materials of Examples 1 to 4 at 25°C; Detailed Embodiments

[0026] To elaborate on the technical content, achieved objectives, and effects of the present invention in detail, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments and with reference to the accompanying drawings. However, the described embodiments are only a part of the embodiments of the present invention, and the implementation and protection of the present invention are not limited thereto. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. It should be noted that, if there is no particularly detailed description of the following processes, those skilled in the art can implement or understand them with reference to the prior art. Reagents or instruments without indicating the manufacturer are regarded as conventional products that can be obtained through commercial purchase.

[0027] Example 1

[0028] S1: Weigh titanium blocks, zirconium blocks, chromium blocks, manganese blocks, iron blocks (with a purity of not less than 99.9 wt.%) and ferrovanadium alloy blocks (vanadium: iron = 80:20) according to the chemical formula Ti 0.890 Zr 0.110 Cr 0.900 Mn 0.800 Fe 0.175 (VFe) 0.125 proportionally, mix them evenly, and place them in a copper crucible of an arc melting furnace; use a molecular pump to pump the air pressure in the furnace to 5.0E-5 Pa, and then fill it with 0.07 MPa of argon gas to melt the above-mentioned mixed materials into one body. After cooling, turn over the combined alloy ingot, and remelt and cool it again. Repeat the melting process 5 times in this way to obtain an alloy ingot; among them, the melting temperature is 2000 °C and the melting time is 2 minutes;

[0029] S2: After the melting is completed, use a grinding wheel to polish the surface of the alloy ingot in the air to remove the oxide layer on the alloy surface. Then, place the alloy ingot in a glove box and crush it into powder, and sieve it through a 200-mesh sieve to obtain the titanium-based hydrogen storage alloy material Ti 0.890 Zr 0.110 Cr 0.900 Mn 0.800 Fe 0.175 (VFe) 0.125 。

[0030] The XRD pattern of the obtained alloy is as shown in Figure 1 and the alloy is a single-phase structure of C14 Laves phase. The backscattered image of 5000 times the surface of the alloy is as shown in Figure 2 (a), presenting a uniform single phase. The first hydrogen absorption kinetic curve of the alloy at 25 °C and 5 MPa-H2 is as shown in Figure 3 and the alloy starts to absorb hydrogen without an incubation period and has not reached saturation when activated for 1800 s, and the hydrogen absorption amount reaches more than 85% of its hydrogen storage capacity at 5 MPa. The hydrogen absorption and desorption PCT (pressure-composition-isotherm) curve of the alloy at 25 °C is as shown inFigure 4 As shown, the hydrogen absorption plateau pressure is 3.01 MPa, the hydrogen desorption plateau pressure is 2.38 MPa, the plateau hysteresis coefficient is 0.235, the plateau slope coefficient is 0.695, the hydrogen absorption at 5 MPa - H₂ is 1.71 wt.%, the residual hydrogen storage capacity during hydrogen desorption at 25 °C and 0.1 MPa - H₂ is 0.11 wt.%, and the reversible hydrogen storage capacity reaches 94%.

[0031] Example 2

[0032] S1: Weigh titanium blocks, zirconium blocks, chromium blocks, manganese blocks, iron blocks, cerium blocks (with a purity of not less than 99.9 wt.%) and ferrovanadium alloy blocks (vanadium:iron = 80:20) according to the chemical general formula Ti 0.890 Zr 0.110 Cr 0.900 Mn 0.800 Fe 0.175 (VFe) 0.125 + 1 wt.% Ce, mix them evenly, and place them in a copper crucible of an arc melting furnace; use a molecular pump to pump the air pressure in the furnace to 5.0E - 5 Pa, then fill it with 0.07 MPa argon, melt the above - mixed materials into one body, after cooling, turn the combined alloy ingot over, and remelt and cool it again. Repeat the melting process 5 times to obtain an alloy ingot; among them, the melting temperature is 2000 °C and the melting time is 2 minutes;

[0033] S2: After the melting is completed, use a grinding wheel to polish the surface of the alloy ingot in the air to remove the oxide layer on the alloy surface, then place the alloy ingot in a glove box and crush it into powder, and sieve it through a 200 - mesh sieve to obtain the titanium - based hydrogen storage alloy material Ti 0.890 Zr 0.110 Cr 0.900 Mn 0.800 Fe 0.175 (VFe) 0.125 + 1 wt.% Ce.

[0034] The XRD pattern of the obtained alloy is as shown in Figure 1 The alloy consists of two sets of diffraction peaks of C14 Laves phase and CeO₂ phase. The backscattered image of the alloy surface at 5000 times magnification is as shown in Figure 2 (b), showing two phases with significantly different contrasts. The position with darker contrast is the C14 Laves phase, while the position with brighter contrast is the CeO₂ phase. The first hydrogen absorption kinetic curve of the alloy at 25 °C and 5 MPa - H₂ is as shown in Figure 3 The alloy starts to absorb hydrogen without an incubation period, and can basically complete hydrogen absorption after 650 s of activation, reaching more than 95% of its hydrogen storage capacity at 5 MPa. The hydrogen absorption - desorption PCT (pressure - composition - isotherm) curve of the alloy at 25 °C is as shown in Figure 4As shown, the hydrogen absorption plateau pressure is 1.70 MPa, the hydrogen desorption plateau pressure is 1.70 MPa, the plateau hysteresis coefficient is 0.004, the plateau slope coefficient is 0.698, the hydrogen absorption at 5 MPa-H2 is 1.65 wt.%, the hydrogen desorption is carried out at 25 °C and 0.1 MPa-H2, the residual hydrogen storage capacity is 0.14 wt.%, and the reversible hydrogen storage capacity reaches 92%.

[0035] Example 3

[0036] S1: According to the chemical general formula Ti 0.890 Zr 0.110 Cr 0.900 Mn 0.800 Fe 0.175 (VFe) 0.125 +2 wt.% Ce ratio, weigh titanium blocks, zirconium blocks, chromium blocks, manganese blocks, iron blocks, cerium blocks (purity not less than 99.9 wt.%) and vanadium-iron alloy (vanadium: iron = 80:20) blocks, mix them evenly, and place them in a copper crucible of an arc melting furnace; use a molecular pump to pump the furnace pressure to 5.0E-5 Pa, then fill it with 0.07 MPa argon, melt the above mixture into one body, turn over the combined alloy ingot after cooling, and remelt and cool it again. Repeat the melting 5 times to obtain an alloy ingot; among them, the melting temperature is 2000 °C and the melting time is 2 minutes;

[0037] S2: After the melting is completed, grind the oxide layer on the surface of the alloy ingot with a grinding wheel in the air, then place the alloy ingot in a glove box and crush it into powder, and sieve it with a 200-mesh sieve to obtain the titanium-based hydrogen storage alloy material Ti 0.890 Zr 0.110 Cr 0.900 Mn 0.800 Fe 0.175 (VFe) 0.125 +2 wt.% Ce.

[0038] The XRD pattern of the obtained alloy is as shown in Figure 1 The alloy consists of two sets of diffraction peaks of C14 Laves phase and CeO2 phase. The backscattered image of the alloy surface at 5000 times is as shown in Figure 2 (c), showing two phases with significantly different contrasts. The position with darker contrast is the C14 Laves phase, and the position with brighter contrast is the CeO2 phase. The first hydrogen absorption kinetic curve of the alloy at 25 °C and 5 MPa-H2 is as shown in Figure 3 The alloy starts to absorb hydrogen without an incubation period, and the hydrogen absorption can be basically completed in 500 s, reaching more than 95% of its hydrogen storage capacity at 5 MPa. The hydrogen absorption and desorption PCT (pressure-composition-isothermal) curve of the alloy at 25 °C is as shown in Figure 4As shown, the hydrogen absorption plateau pressure is 2.13 MPa, the hydrogen desorption plateau pressure is 1.93 MPa, the plateau hysteresis coefficient is 0.099, the plateau slope coefficient is 0.724, the hydrogen absorption is 1.66 wt.% at 5 MPa-H2, the hydrogen desorption is carried out at 25 °C and 0.1 MPa-H2, the residual hydrogen storage capacity is 0.11 wt.%, and the reversible hydrogen storage capacity reaches 93%.

[0039] Example 4

[0040] S1: According to the chemical general formula Ti 0.890 Zr 0.110 Cr 0.900 Mn 0.800 Fe 0.175 (VFe) 0.125 + 3 wt.% Ce ratio, weigh titanium blocks, zirconium blocks, chromium blocks, manganese blocks, iron blocks, cerium blocks (purity not less than 99.9 wt.%) and vanadium-iron alloy (vanadium:iron = 80:20) blocks, mix them evenly, and place them in a copper crucible of an arc melting furnace; use a molecular pump to pump the furnace pressure to 5.0E-5 Pa, then fill it with 0.07 MPa argon, melt the above mixture into one body, turn over the combined alloy ingot after cooling, and remelt and cool it again. Repeat the melting 5 times to obtain an alloy ingot; among them, the melting temperature is 2000 °C and the melting time is 2 minutes;

[0041] S2: After the melting is completed, grind the oxide layer on the surface of the alloy ingot with a grinding wheel in the air, then place the alloy ingot in a glove box and crush it into powder, and sieve it with a 200-mesh sieve to obtain the titanium-based hydrogen storage alloy material Ti 0.890 Zr 0.110 Cr 0.900 Mn 0.800 Fe 0.175 (VFe) 0.125 + 3 wt.% Ce.

[0042] The XRD pattern of the obtained alloy is as Figure 1 shown. The alloy consists of two sets of diffraction peaks of C14 Laves phase and CeO2 phase. The backscattered image of 5000 times the surface of the alloy is as Figure 2 (b) shown, presenting two phases with significantly different contrasts. The position with darker contrast is the C14 Laves phase, while the position with brighter contrast is the CeO2 phase. The first hydrogen absorption kinetic curve of the alloy at 25 °C and 5 MPa-H2 is as Figure 3 shown. The alloy starts to absorb hydrogen without an incubation period and can basically complete hydrogen absorption in 200 s, reaching more than 95% of its hydrogen storage capacity at 5 MPa. The hydrogen absorption and desorption PCT (pressure-composition-isothermal) curve of the alloy at 25 °C is as Figure 4As shown, the hydrogen absorption plateau pressure is 2.30 MPa, the hydrogen desorption plateau pressure is 1.95 MPa, the plateau hysteresis coefficient is 0.167, the plateau slope coefficient is 0.899, the hydrogen absorption is 1.64 wt.% at 5 MPa-H2, the hydrogen desorption is carried out at 25 °C and 0.1 MPa-H2, and the residual hydrogen storage capacity is 0.11 wt.%, and the reversible hydrogen storage capacity reaches 93%.

[0043] The titanium-based hydrogen storage alloy material Ti of the present invention 0.890 Zr 0.110 Cr 0.900 Mn 0.800 Fe 0.175 (VFe) 0.125 + x wt.% Ce, where x is 0 to 5, has excellent hydrogen absorption and desorption performance: the hydrogen absorption and desorption plateau pressures are appropriate (the hydrogen absorption plateau pressure < 3.5 MPa, the hydrogen desorption plateau pressure > 1.5 MPa), the plateau hysteresis is small, the plateau slope is small, the reversible hydrogen storage capacity is large (the reversible hydrogen storage capacity reaches more than 90%), and the hydrogen absorption and desorption kinetics are fast, which can meet the application conditions of kilowatt-level fuel cells for heavy machinery.

[0044] It can be seen from Examples 1-4 that for the titanium-based hydrogen storage alloy material of the present invention, x is preferably 1-3. Adding a certain proportion of Ce can significantly improve the activation performance of the alloy material and at the same time improve its hydrogen absorption and desorption performance (effectively reducing the hydrogen absorption plateau pressure and reducing the plateau hysteresis coefficient, and the plateau slope < 1). No activation treatment is required before hydrogen absorption, significantly reducing the activation cost, and the hydrogenation time is short, which is beneficial to broadening the practical application of Ti-based AB2 type hydrogen storage alloys in kilowatt-level fuel cells. When the Ce content is 2 wt.%, the activation performance and hydrogen absorption and desorption performance of the alloy material reach the optimal balance.

[0045] The Ce content of the titanium-based hydrogen storage alloy material of the present invention cannot be too high. When x > 5, the Ce content is too high. Although the activation performance is excellent, it will instead lead to too high hydrogen absorption plateau pressure and relatively large plateau hysteresis, resulting in a large pressure difference between the hydrogenation pressure of the hydrogen refueling station and the hydrogen desorption pressure of the battery, which is not conducive to their coordinated use, and will greatly increase the plateau slope, making the working hydrogen pressure of the battery unstable and unable to meet the application conditions of kilowatt-level fuel cells for heavy machinery.

[0046] For those skilled in the art, the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms; therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be regarded as limiting the claimed rights.

[0047] All of the above embodiments are preferred embodiments of the present invention. However, the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent substitution methods and are all included in the protection scope of the present invention.

Claims

1. A titanium-based hydrogen storage alloy material, characterized in that: Its elemental composition is Ti 0.890 Zr 0.110 Cr 0.900 Mn 0.800 Fe 0.175 (VFe) 0.125 +x wt.%Ce, wherein x is 0 to 5.

2. The titanium-based hydrogen storage alloy material according to claim 1, characterized in that: The x is 1-3.

3. The titanium-based hydrogen storage alloy material according to claim 1, characterized in that: The titanium-based hydrogen storage alloy material has a dual-phase structure with a C14 Laves phase as a main phase and a CeO2 phase as a second phase.

4. The method for preparing a titanium-based hydrogen storage alloy material according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Weigh titanium, zirconium, chromium, manganese, iron, cerium single metals and vanadium-iron alloy with a purity of ≥99.9% as smelting raw materials in proportion, melt them in a non-consumable vacuum arc melting furnace, and obtain alloy ingots after cooling; S2. Grinding to remove the oxide layer on the surface of the alloy ingot, mechanically crushing and screening, and preparing a titanium-based hydrogen storage alloy material.

5. The method for preparing a titanium-based hydrogen storage alloy material according to claim 4, characterized in that: Before smelting, the vacuum degree in the furnace is ≤5.0E-5Pa, and the atmosphere in the furnace is 0.06-0.07MPa argon atmosphere during smelting.

6. The method for preparing a titanium-based hydrogen storage alloy material according to claim 4, characterized in that: Melting temperature ≥2000℃.

7. The method for preparing a titanium-based hydrogen storage alloy material according to claim 4, characterized in that: The alloy ingot obtained by smelting is turned over and re-melted and cooled, and the process is repeated for multiple times, with each melting time being 1-2 minutes and the number of turning over and re-melting is not less than 5 times.

8. The method for preparing a titanium-based hydrogen storage alloy material according to claim 4, characterized in that: The smelting raw materials are first polished to remove the surface oxide layer before smelting.

9. Use of the titanium-based hydrogen storage alloy material according to any one of claims 1 to 3 in a kilowatt-class fuel cell.

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