AB5 type hydrogen storage alloy, its preparation method and applications

Abstract

This invention relates to metal hydrides for hydrogen storage, particularly AB5-based metal hydrides, as well as their production methods and uses.

Description

[0001] Invention Field

[0002] This invention relates to metal hydrides for storing gaseous hydrogen, particularly AB5 type metal hydrides, as well as their production methods and applications. Background of the Invention

[0004] Hydrogen storage is a key step in decarbonizing fossil fuel technologies using renewable energy sources. Various storage methods were considered, including pressurized gas storage, hydrogen liquefaction, and absorption using solid materials.

[0005] There are three types of hydrogen storage materials: hydrogen storage materials that store hydrogen on the surface of the material by absorption, hydrogen storage materials that store hydrogen inside the material by absorption, and hydride storage that uses a combination of solid materials and liquids.

[0006] Hydride storage utilizes the reaction of hydrogen. This method of storing hydrogen, also known as "chemical hydrogen storage," is based on interstitial compounds formed by hydrogen with elemental metals (such as palladium, magnesium, and lanthanum), intermetallic compounds, light metals (such as aluminum), or certain alloys. Metal hydrides break down hydrogen molecules into atoms on their surface and store them within the metal lattice, thereby generating heat. Conversely, heat is absorbed when hydrogen is released from the hydride. These hydrides can absorb large amounts of gas; for example, palladium can absorb 900 times its own volume of hydrogen. The process is as follows: a) Absorption: Hydrogen molecules (H2) adhere to the metal surface and then dissociate on the metal surface before absorption, breaking down into hydrogen atoms (H). The hydrogen atoms then enter the interior of the metal crystal, forming a new solid substance called a "metal hydride." Metal atoms are typically pulled apart to accommodate hydrogen atoms. The physical arrangement (structure) of the metal atoms can also be altered to form hydrides; b) Desorption: Hydrogen atoms migrate to the surface of the metal hydride, combine with hydrogen molecules (H2), and flow out as hydrogen gas. Metal atoms contract to form the original metal crystal structure.

[0007] like Figure 1A The pressure-composition isotherm shown describes the thermodynamic aspects of the formation of hydrides from gaseous hydrogen. Figure 1A Typical absorption and desorption isotherms of H2 in metal hydrides are shown at different temperatures. The hydrogen absorption reaction in the material is typically exothermic (generating heat), while the hydrogen desorption reaction is endothermic (absorbing heat). The low pressure and thermodynamics of the metal hydride system enhance system safety: in the event of container failure, hydrogen will be slowly released, a process thermally limited by the endothermic desorption reaction. Generally, a good H2 storage capacity is considered to be greater than 1.45 wt%.

[0008] Various metal alloys and intermetallic compounds react with hydrogen to form metal hydrides. The direction of the chemical reaction can be controlled by appropriately regulating temperature and pressure. Typical metal hydrides exist in powder form with particle sizes only a few millionths of a meter (micrometer).

[0009] Therefore, compared to compressed gas or liquefied hydrogen storage systems, metal hydride storage systems are safer, more reliable, and more compact. Furthermore, they require minimal maintenance and have a long service life. Consequently, since many metals and alloys can reversibly absorb large amounts of hydrogen, metal hydrides have excellent applications for storing hydrogen at low pressures, thus achieving pressures up to 150 kgkh / m³. 3 Its high volume density has become the subject of many recent developments. (Bellosta von Colbe et al., 2019, internationality International Journal of Hydrogen Energy, 44, 7780-7808 ).

[0010] Metals belonging to Groups IIA to VA in the periodic table readily combine with hydrogen to form metal hydrides. AB2-type alloys are particularly noteworthy, where metal A is Ti or Zr and metal B is a third transition state metal. Another alloy type is AB5. Typical examples are LaNi5 and CaNi5. These alloys have a hydrogen storage capacity of approximately H / M = 1. Due to the excellent hydrogen absorption properties of LaNi5, its characteristics and fundamental properties have been extensively studied. Different types of hydrogen storage materials (e.g., magnesium-based hydrogen storage materials and AB2 / AB5 hydrogen storage materials) have been synthesized, screened, and evaluated on a laboratory scale, but only a few have been selected for the development of full-scale hydrogen storage tank systems.

[0011] In fact, most known commercial metal hydrides have been developed for electrochemical applications in NiMH batteries. These alloys need to operate in an electrolyte environment, and their plateau pressure is typically below 1 bar at room temperature to keep the internal pressure of the battery within a safe range. For example, in CN 102828069, Wang et al. protect a praseodymium-neodymium-free, low-cost, ultra-long-life hydrogen storage alloy for batteries with a plateau pressure of less than 0.1 MPa. Figure 1B This low hydrogen storage / release pressure at room temperature is unsuitable for hydrogen energy storage and compression systems because fuel cell systems or pressurized tanks typically require input H2 pressures higher than 5 bar, sometimes even higher than 10 bar, and the operating environment is usually gaseous hydrogen. Some AB5 alloys have been developed for high-pressure gas applications. In particular, CN106854715 protects a La a Y b Mg c Ca d Ni9 alloy can also be used for gaseous hydrogen storage applications. However, its pressure plateau has a very steep slope, with a plateau pressure of only 10 atm at room temperature. Figure 1C The alloy's poor reversibility results in a low usable capacity in applications. The use of magnesium and calcium, with their highly volatile characteristics, significantly increases the difficulty of large-scale production. Furthermore, several AB5 alloys have been developed for manufacturing anodes in Ni-MJ batteries (US 5817222; JP2001200324; US2004 / 194577), but these are low-pressure metal hydrides and are unsuitable for storing gaseous hydrogen under high-pressure conditions.

[0012] Another problem with currently available AB5 materials under high-pressure applications is the high hysteresis between hydrogen absorption and desorption processes. When the dehydrogenation pressure increases to above 10 bar, the alloy's hysteresis often exceeds 12 bar. Invention Overview

[0014] The purpose of this invention is to provide an AB5 type alloy suitable for storing gaseous hydrogen under high pressure (e.g., >5 bar at room temperature).

[0015] Advantageously, an AB5 type alloy with a long cycle life (>2000) and relatively low hysteresis (<5 bar) is provided.

[0016] Advantageously, an AB5 type alloy is provided that maintains good total absorption capacity (e.g., >1.45 wt.%) even when the dehydrogenation pressure exceeds 50 bar at room temperature.

[0017] Advantageously, an AB5 type alloy is provided, which has a flat absorption / desorption plateau pressure suitable for solid hydrogen storage and compression systems.

[0018] The object of the present invention is achieved by providing Ni-based AB5 type metal hydride alloys, their powders, and uses of AB5 type metal hydride alloys.

[0019] The objective of this invention is to provide a method for preparing Ni-based AB5 metal hydride alloys.

[0020] The purpose of this invention is to provide a hydrogen storage system.

[0021] This invention discloses a hydrogen storage alloy with an AB5-type crystal structure, wherein the A-site contains La, Ce, and MI elements, and the B-site contains Ni, Co, and Fe elements. The hydrogen storage alloy is shown in formula (I) below:

[0022]

[0023] Where x, y, a, b, c, and d are molar ratios, MI is at least one element selected from Y, Ti, and Zr, and M is selected from Cu and Mn; 0.15≤x≤0.95; 0.05≤y≤0.85; 0≤(1-xy)≤0.1; 3.8≤a≤4.2; 0.1≤b≤1.2; 0.01≤c≤0.3; 0≤d≤0.1; 4.8≤(a+b+c+d)≤5.15.

[0024] This invention also discloses a method for preparing a hydrogen storage alloy with an AB5-type crystal structure by rapid melt solidification through roller quenching, the method comprising the following steps:

[0025] - Melt all metallic elements in a furnace under a controlled inert atmosphere (e.g., argon) and a pressure of approximately 30 kPa to approximately 70 kPa;

[0026] - The molten material in the furnace is poured onto a rotating roller that rotates at a speed of about 1 m / s to about 9 m / s. The molten material solidifies rapidly and breaks into flakes as it enters a cooling device (e.g., a water-cooled collector).

[0027] - Further cool the sheet to below 50°C;

[0028] - Air is introduced into the furnace, and the resulting thin sheets are collected.

[0029] This article also discloses a hydrogen storage system, which includes the AB5 type alloy described in this invention.

[0030] Other objects and advantages of the invention will become apparent from the claims and the following detailed description and accompanying drawings.

[0031] Brief description of the attached figures

[0032] The invention will now be described with reference to the accompanying drawings, which illustrate the invention by way of example, in which:

[0033] Figure 1 shows the pressure-composition-temperature (PCT) isotherm of a metal hydride. 1A: Schematic diagram of a typical metal hydride for hydrogen storage (https: / / www.ctcms.nist.gov / hydrogen_storage / research_pct.html); 1B: PCT curve of the material described in CN102828069; 1C: PCT curve of the material described in CN106854715.

[0034] Figure 2 shows the pressure-composition-temperature (PCT) isotherm of the metal hydride of the present invention. 2A: As described in Example 2; 2B: As described in Example 2.

[0035] Figure 3 The pressure-composition-temperature (PCT) isotherms of the metal hydride described in this invention compared to the low-pressure AB5 alloys for Ni-MH batteries described in Example 3 at 30°C (3A & 3B) and 40°C (3C & 3D). 3A: Alloys similar to those in Example 1 of US5817222 (La... 0.25 Ce 0.5 Pr 0.05 Nd 0.2 Ni 3.39 Al 0.19 Co 0.92 Mn 0.48 Fe 0.02 ); 3B: Alloy of the present invention with a similar La content (0.25) ((La 0.25 Ce 0.7 Ti 0.05 Ni 4.0 Co 0.8 Fe 0.2 ); 3C: An alloy having a composition similar to that of Example 2 of JP 2001200324 (La) 0.8 Ce 0.12 Pr 0.04 Nd 0.04 Ni 4.15 Co 0.4 Mn 0.35 Al 0.3 Fe 0.02 Mg 0.3 ); 3D: Alloy of the present invention with a similar La content (0.8) 0.8 Ce 0.18 Zr 0.2 Ni 4.0 Co 0.8 Fe 0.1 Cu 0.1 ).

[0036] Figure 4 This is a schematic diagram of a method for preparing the alloy of the present invention by rapid melt solidification through spinning roller quenching.

[0037] Detailed description of embodiments of the present invention

[0038] According to one particular aspect, a hydrogen storage alloy having an AB5-type crystal structure as shown in formula (I) is provided, wherein b, c, d, MI and M are as described above, and 0.15≤x≤0.45 and 0.55≤y≤0.85 (alloy (Ia)).

[0039] According to another specific aspect, a hydrogen storage alloy having an AB5-type crystal structure as shown in formula (I) is provided, wherein b, c, d, MI and M are as described above, and 0.55≤x≤0.95 and 0.05≤y≤0.45 (alloy (Ib)).

[0040] According to a particular aspect, a hydrogen storage alloy having an AB5-type crystal structure as shown in formula (I) is provided, wherein 0.9≤x+y≤1.

[0041] According to a particular aspect, a hydrogen storage alloy is provided, the hydrogen storage alloy being selected from the group consisting of:

[0042] .

[0043] In this invention, the hydrogen storage alloy has a hydrogen absorption plateau between 5-150 bar and a desorption plateau between 3-100 bar at 25°C.

[0044] In this invention, the hydrogen storage alloy has a hydrogen storage capacity of about 1.4 wt% to about 1.55 wt% (typically about 1.45 wt% to 1.50 wt%) at 25°C.

[0045] The hydrogen storage alloy of the present invention can be prepared by, for example, the typical method for AB5 alloy described in CN1602366.

[0046] Typically, for batches up to 300 kg, the raw materials for each desired metallic element are placed in a water-cooled copper crucible within an electric arc melting furnace, and the furnace is placed under vacuum (e.g., 5). 10 -3 The raw material is placed in a furnace at a pressure of approximately 30 kPa to approximately 70 kPa (e.g., 50 kPa (PABS)) and then filled with a controlled gas (e.g., Ar, > 99.99%). The raw material is melted and held at the melting temperature for approximately 5 to 10 minutes. The molten mixture is then allowed to solidify. The solidified alloy (ingot) is inverted and remelted, and this process is repeated several times (e.g., 2 to 6 times, e.g., 3 times) to ensure a homogeneous alloy composition. When the last cycle is completed and the temperature of the solidified alloy is below 50°C, the furnace is connected to air, and the ingot alloy is collected.

[0047] Advantageously, for batches ranging from 3 kg to approximately 1000 kg, a method is provided for preparing hydrogen storage alloys with an AB5-type crystal structure via rapid melt solidification through roller quenching. In particular, compared to arc melting, this method produces alloys with more homogeneous composition, stable crystal structure, fewer phases outside the AB5 structure, and lower crystal strain (thus exhibiting lower hysteresis and a flatter plateau pressure). This alloy requires heat treatment before use while maintaining a long cycle life. This method is also suitable for large-scale production, significantly reducing production costs.

[0048] According to one specific implementation, the metal element is purified and placed in a vacuum (e.g., 5). 10 -3 The metal is melted in a furnace at a pressure of about 30 kPa to about 70 kPa (e.g., 50 kPa (PABS)) and then filled with a controlled inert atmosphere (e.g., argon or helium > 99.99%).

[0049] According to a further specific embodiment, the metal element is melted in an Al2O3-based crucible placed in a furnace.

[0050] According to a further specific embodiment, after all the metal has melted, the temperature is reduced to between approximately 1350°C and 1450°C and held for approximately 5 to 10 minutes.

[0051] refer to Figure 4 The metal mixture is melted in a crucible 1 (e.g., heated by an induction coil 2) placed in a furnace under the controlled atmosphere, and then cast onto a rotating roller 3 (e.g., a copper roller) that rotates at a certain speed. The melt solidifies rapidly and breaks into flakes 4 as it enters a cooling device (e.g., a water-cooled collector).

[0052] According to a further specific embodiment, the molten mixture is poured onto a rotating roller (e.g., a copper roller) rotating at a constant speed of about 1.5 m / s to about 9 m / s, wherein the melt rapidly solidifies and breaks into flakes. The thickness of the flakes depends on the rotational speed of the roller; the lower the speed, the thicker the flakes. Depending on specific aspects, the thickness of the flakes is typically between 0.1 and 0.6 mm.

[0053] According to a further specific embodiment, the sheet is left in the furnace to cool at a certain temperature in a water-cooling chamber.

[0054] The alloy of this invention can be used directly from the resulting sheet, or it can be heat-treated below the alloy's melting temperature when needed. Heat treatment further reduces hysteresis and improves cycling performance. Typically, heat treatment is performed in a vacuum (e.g., 9...). 10 -2The process is carried out in a furnace at a pressure of approximately 30 kPa to approximately 70 kPa (PABS), where the temperature is raised to approximately 200°C and held for approximately 20 min. Before further raising the furnace temperature, the furnace is filled with an inert atmosphere (e.g., pure argon (>99.99%)) at a pressure of approximately 30 kPa to approximately 70 kPa (e.g., to 50 kPa PABS). The furnace temperature is then raised to between approximately 850°C and 150°C and held for approximately 0.5 h to approximately 72 h. The temperature-treated alloy is then cooled at a rate of approximately 5 K / min to approximately 20 K / min. When the alloy temperature is below 60°C, the furnace is connected to air, and the alloy is collected.

[0055] According to a further embodiment, a method is provided for preparing a hydrogen storage alloy with an AB5-type crystal structure by rapid melt solidification through roller quenching, wherein the method further includes a heat treatment step.

[0056] The alloy described in this invention (with or without heat treatment) can be used in powder form. Specifically, the resulting alloy is pressed into powder by mechanical or jet milling under an inert gas (e.g., N2 or Ar, preferably Ar). Typically, the particle size of the alloy can be between about 0.5 mm and about 3 mm, depending on the hydrogen storage system it will be used in.

[0057] Alloy powders can be stored as powders under vacuum or inert gas (e.g., N2 or Ar, preferably Ar).

[0058] Alloy powders can be used in hydrogen storage systems, as described by Bellosta von Colbe et al., 2019.

[0059] Embodiments of the present invention will now be described in more detail with reference to the examples shown in the figures.

[0060] Example

[0061] Example 1: Preparation of the alloy described in this invention

[0062] Example 1a): Preparation using an electric arc melting furnace

[0063] The alloys of the present invention are prepared, particularly those of formula La. 0.6 Ce 0.3 Ni 4.2 Co 0.3 Fe 0.4 Mn 0.1 Preparation of (Ia) alloy.

[0064] Prepare the required amount of metal, totaling 1 kg, according to the formula, and place it in a water-cooled copper crucible in an electric arc melting furnace. Evacuate the furnace until the vacuum reaches 5... 10 -3Pa (PABS). Then, fill the furnace with pure argon (>99.99%) to a pressure of 50 kPa (PABS). Then increase the power until the raw material begins to melt. Melt all the metal and maintain the power for 5 minutes. Then stop melting and wait until the alloy solidifies. Invert the alloy and melt it again, repeating this step 3 times to make the alloy composition more homogeneous. Then wait until the temperature of the sheet drops below 50°C. Finally, refill the furnace with air and remove the alloy as an ingot.

[0065] After melting, the prepared alloy is placed in a heat treatment furnace. The furnace is then evacuated until the vacuum reaches 90°C. 10 -2 Pa (PABS). The temperature was then raised to 200°C and held for 30 min. The furnace was then filled with pure argon (>99.99%) to a pressure of 50 kPa (PABS). The temperature was then raised to 800°C and held for 36 h. The alloy was then cooled at a rate of 5 K / min, waiting until the alloy temperature dropped below 60°C. Finally, the furnace was refilled with air to atmospheric pressure, and the alloy was removed from the furnace.

[0066] Example 1b: Preparation using an induction furnace

[0067] The alloys of the present invention are prepared, particularly those of the formula La. 0.3 Ce 0.65 Ti 0.05 Ni 3.8 Co 0.2 Fe 1.0 (Preparation of Ib alloys)

[0068] The required amount of metal, weighed according to formula Ib, totaling 750 kg, was placed in an Al₂O₃-based crucible within an industrial induction furnace. The furnace was then evacuated until a vacuum of 5... 10 -3 The metal was heated to 1450°C and melted. After all the metal had melted, the temperature was lowered to 1350°C and held for 10 minutes. The melt was then poured onto a rotating copper roller at a speed of 5 m / s to form a sheet approximately 0.1 mm thick. The solidified sheet was then guided into a water-cooling chamber for further cooling. The furnace was refilled with air, and the sheet was removed when its temperature dropped below 50°C. The alloy can be used without further processing.

[0069] Example 1c: Hydrogen storage performance of the prepared alloy

[0070] The alloys of the present invention and their hydrogen storage properties provided as illustrative examples are listed in Table 1 below.

[0071] Table 1

[0072]

[0073] Example 2: Hydrogen storage capacity of the alloy of the present invention

[0074] The hydrogen storage performance of the alloy prepared in Example 1 was tested as follows: 3 g of alloy ingot / sheet was crushed into powder (particle size <100 mesh) and added to a stainless steel cylindrical sample chamber. The alloy was charged with hydrogen at a constant 5 MPa hydrogen pressure for 2 h. Then the sample was evacuated for 30 min. The hydrogen charging-evacuation step was repeated at least 3 times to fully activate the alloy.

[0075] A fully automated, computer-controlled volumetric instrument (called a Sievert instrument, or PCT instrument) will be used to determine the amount of hydrogen absorbed by the alloy in a 25°C water bath.

[0076] As shown in Figure 2, the alloy of the present invention has a higher and wider desorption plateau than conventional AB5 alloys, especially those used in NiMH batteries at room temperature. Advantageously, the H2 charging pressure is also higher. The alloy prepared in Example 1 is similar to US5817222 ( Figure 3 A&3B) and JP 2001200324 ( Figure 3 The AB5 alloy for NiMH batteries described in C&3D was compared similarly at higher temperatures (i.e., at 30°C and 40°C).

[0077] like Figure 3 As shown, an alloy similar to the embodiment of US 5817222 (La) 0.25 Ce 0.5 Pr 0.05 Nd 0.2 Ni 3.39 Al 0.19 Co 0.92 Mn 0.48 Fe 0.02 (3A) and the alloy of the present invention (La) having a similar La content (0.25). 0.25 Ce 0.7 Ti 0.05 N i4.0 Co 0.8 Fe 0.2 (3B) In comparison, the alloy plateau pressure of the alloy of the present invention is typically higher than 1 atm, and typically higher than 2 atm, while the hydrogen pressure storage of the comparative alloy is lower than 0.3 atm. When compared with the alloy of Example 2 of JP 2001200324 (La) having a similar composition... 0.8Ce 0.12 Pr 0.04 Nd 0.04 Ni 4.15 Co 0.4 Mn 0.35 Al 0.3 Fe 0.02 Mg 0.3 (3C) and the alloy of the present invention (La) having a similar La content (0.8). 0.8 Ce 0.18 Zr 0.2 Ni4 .0 Co 0.8 Fe 0.1 Cu 0.1 This was also confirmed when (3D) was used.

[0078] Therefore, these data support the claim that the AB5 alloy described in this invention exhibits better performance than known alloys under high H2 pressure, and that production costs are reduced due to the absence of Pr and Nd.

Claims

1. A hydrogen storage alloy with an AB5-type crystal structure, wherein the A-site contains La, Ce, and MI elements, and the B-site contains Ni, Co, and Fe elements, as shown in formula (I): ； wherein x, y, a, b, c, and d are molar ratios; MI is at least one element selected from Y, Ti, and Zr; M is selected from Cu and Mn; 0.15≤x≤0.95; 0.05≤y≤0.85; 0≤(1-xy)≤0.1; 3.8≤a≤4.2; 0.1≤b≤1.2; 0.01≤c≤0.3; 0≤d≤0.1; 4.8≤(a+b+c+d)≤5.

15.

2. The hydrogen storage alloy as described in claim 1, characterized in that, 0.15≤x≤0.45, 0.55≤y≤0.

85.

3. The hydrogen storage alloy as described in claim 1, characterized in that, 0.55≤x≤0.95, 0.05≤y≤0.

45.

4. The hydrogen storage alloy as described in claim 1, characterized in that, 0.9≤x+y≤1.

5. The hydrogen storage alloy as described in claim 1, characterized in that, The hydrogen storage alloy is selected from the following group: 。 6. A hydrogen storage alloy, characterized in that, The hydrogen storage alloy is 。 7. The hydrogen storage alloy as described in claim 1 or 2, characterized in that, The hydrogen storage alloy exhibits a hydrogen absorption plateau between 5 and 150 bar and a desorption plateau between 3 and 100 bar at 25°C.

8. The hydrogen storage alloy as described in claim 1 or 2, characterized in that, The hydrogen storage alloy has a hydrogen storage capacity of 1.4 wt% to 1.55 wt% at 25°C.

9. The hydrogen storage alloy as described in claim 1 or 2, characterized in that, The hydrogen storage alloy has a hydrogen storage capacity of 1.45 wt% to 1.50 wt% at 25°C.

10. A method for preparing a hydrogen storage alloy with an AB5-type crystal structure as described in claim 1 by rapid melt solidification through roller quenching, characterized in that, The method includes the following steps: - All metallic elements are melted in a furnace under a controlled inert atmosphere and pressures of 30 kPa to 70 kPa; - The molten material in the furnace is poured onto a rotating roller that rolls at a speed of 1.5 m / s to 9 m / s. The molten material solidifies rapidly and breaks into thin sheets as it enters the cooling device. - Further cool the sheet to below 50°C; - Air is introduced into the furnace, and the alloy is collected.

11. The method as described in claim 10, characterized in that, The rotating roller rolls at a constant speed of 1.5 m / s to 9 m / s.

12. The method as described in claim 11, characterized in that, The rotating roller is a copper roller.

13. The method as described in claim 10, characterized in that, The resulting alloy was further subjected to a temperature treatment of 0.5 h to 72 h at a temperature between 850°C and 150°C.

14. An alloy prepared by the method as described in claim 10 or 13.

15. A powder of the alloy as described in claim 1 or 14, characterized in that, The alloy has a particle size of 0.5 mm to 3 mm.

16. Use of the alloy as described in claim 1 or 14 in hydrogen storage.

17. A hydrogen storage system comprising the alloy as described in claim 1 or 14.

18. A hydrogen storage system comprising powder of the alloy as described in claim 1 or 14.

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