Aluminum-containing hydrogen storage alloy, method for producing the same, and use of calcium

Abstract

The application discloses an aluminum-containing hydrogen storage alloy, a preparation method thereof and a use of calcium element. a Ce b Y c Ca d Ni x Mn y Al z (1); wherein x, y, z, a, b, c and d represent molar fractions of respective elements; 2 >= a >= 0.1, 2.3 >= b >= 0.8, 4.2 >= c >= 1.8, 1 >= d >= 0, 20.5 >= x >= 19.5, 0.8 >= y >= 0.4, 0.5 >= z >= 0.05, and a+b+c+d = 6 and x+y+z = 21. The aluminum-containing hydrogen storage alloy has a high hydrogen storage capacity at a pressure of 0.1 MPa or above and a low hydrogen desorption plateau pressure.

Description

Technical Field

[0001] This invention relates to an aluminum-containing hydrogen storage alloy, its preparation method, and the use of calcium. Background Technology

[0002] Hydrogen energy, with its abundant reserves, wide availability, and zero pollution, is considered an ideal new energy source. Hydrogen transportation is a crucial link in the popularization and application of hydrogen energy. However, hydrogen is prone to leakage and contact with air during transportation, posing a potential explosion hazard. Therefore, how to efficiently and conveniently store and transport hydrogen has become an important issue in promoting the development of hydrogen energy systems. Rare earth metal hydrides stand out among various hydrogen storage materials due to their mild storage conditions and high safety and efficiency.

[0003] CN116479287A discloses an A5B 19 Type La-Y-Ni hydrogen storage alloy, its chemical composition is La 5-x Y x Ni 19- y R y Where 2.78≤x≤3.34, 0≤y≤1.5, and R is one or more of Mn, Al, Co, Zr, Cr, Sc, Ti, V, Nb, and Mo. This hydrogen storage alloy is A5B. 19 It is a type, and its hydrogen storage capacity above 0.1 MPa accounts for a relatively small proportion.

[0004] CN116024459A discloses a superlattice rare-earth hydrogen storage material with the chemical formula A. a Ce b Y c Ni x Mn y B z The following conditions must be met: 0.3≤b≤0.9, 1.6≤c≤2.5, a+b+c=3, 0.3≤y≤0.7, 0≤z≤0.3, 10.8≤x+y+z≤12.6, where A is one or more of La selected from La, Pr, Nd, Gd, or Sm, and B is one or more of Al, Cu, Fe, Zn, Co, Si, Zr, or Ti. The hydrogen storage capacity of this rare earth hydrogen storage material above 0.1 MPa is relatively small.

[0005] CN114955988A discloses a rare-earth yttrium nickel hydrogen storage alloy with an A2B7 type structure and a chemical composition of RE. x Y y Ni z-a-b Mn a Al bRE is one or more of La, Ce, Pr, Nd, Sm and Gd, x>0, y>0, x+y=3 and 1.6≤y / x≤2.4, 0<a+b≤1, 9.15≤z≤11.85. The hydrogen storage alloy has a relatively small proportion of hydrogen storage capacity above 0.1MPa. Summary of the Invention

[0006] In view of this, one object of the present invention is to provide an aluminum-containing hydrogen storage alloy, which has a high proportion of hydrogen storage capacity above 0.1 MPa and a low hydrogen release plateau pressure. Furthermore, this aluminum-containing hydrogen storage alloy has a high reversible hydrogen storage capacity. Another object of the present invention is to provide a method for preparing the above-mentioned aluminum-containing hydrogen storage alloy. A further object of the present invention is to provide the use of calcium in improving the reversible hydrogen storage capacity of aluminum-containing hydrogen storage alloys.

[0007] The present invention achieves the above-mentioned technical objectives through the following technical solutions.

[0008] On the one hand, the present invention provides an aluminum-containing hydrogen storage alloy, characterized in that it has a composition represented by formula (1):

[0009] La a Ce b Y c Ca d Ni x Mn y Al z (1)

[0010] Where x, y, z, a, b, c, d represent the mole fractions of each element; 2≥a≥0.1, 2.3≥b≥0.8, 4.2≥c≥1.8, 1≥d≥0, 20.5≥x≥19.5, 0.8≥y≥0.4, 0.5≥z≥0.05, and a+b+c+d=6, x+y+z=21.

[0011] In the aluminum-containing hydrogen storage alloy according to the present invention, preferably, 0.8 ≥ d ≥ 0.1.

[0012] According to the aluminum-containing hydrogen storage alloy of the present invention, preferably, the content of Ce2Ni7 phase in the aluminum-containing hydrogen storage alloy is greater than or equal to 55wt%.

[0013] According to the aluminum-containing hydrogen storage alloy of the present invention, preferably, 1.3≥a≥0.8, 1.3≥b≥1, 4≥c≥3.5, and d=0.

[0014] According to the aluminum-containing hydrogen storage alloy of the present invention, preferably, 2≥a≥1.8, 1.8≥b≥1.5, 2.5≥c≥2, and 0.6≥d≥0.3.

[0015] According to the aluminum-containing hydrogen storage alloy of the present invention, preferably, 20.3≥x≥20, 0.7≥y≥0.5, and 0.4≥z≥0.1.

[0016] According to the present invention, the aluminum-containing hydrogen storage alloy preferably has a composition represented by one of the following formulas:

[0017] LaCeY4Ni 20.1 Mn 0.6 Al 0.3 ;

[0018] LaCeY4Ni 20.2 Mn 0.6 Al 0.2 ;

[0019] LaCeY4Ni 20.3 Mn 0.6 Al 0.1 ;

[0020] La 0.6 Ce 1.4 Y4Ni 20.2 Mn 0.6 Al 0.2 ;

[0021] La 0.6 Ce 1.4 Y4Ni 20.3 Mn 0.6 Al 0.1 ;

[0022] La 0.4 Ce 1.6 Y4Ni 20.3 Mn 0.6 Al 0.1 ;

[0023] La 0.2 Ce 1.8 Y4Ni 20.3 Mn 0.6 Al 0.1 ;

[0024] La2CeY3Ni 20.3 Mn 0.6 Al 0.1 ;

[0025] La2Ce 1.5 Y 2.5 Ni 20.3 Mn 0.6 Al 0.1 ;

[0026] La2Ce 1.5 Y2Ca0.5 Ni 20.3 Mn 0.6 Al 0.1 ;

[0027] LaCeY4Ni 20 Mn 0.6 Al 0.4 ;

[0028] La2Ce2Y2Ni 20.3 Mn 0.6 Al 0.1 .

[0029] On the other hand, the present invention provides a method for preparing the above-mentioned aluminum-containing hydrogen storage alloy, comprising the following steps:

[0030] (1) Provide raw materials according to the chemical composition described in formula (1), melt and shape the raw materials to obtain alloy sheets;

[0031] (2) Anneal the alloy sheet in an inert atmosphere to obtain an annealed alloy sheet;

[0032] (3) The annealed alloy sheet is pulverized to obtain an aluminum-containing hydrogen storage alloy.

[0033] According to the preparation method of the present invention, preferably, annealing the alloy sheet in an inert atmosphere includes the following steps:

[0034] The alloy sheet is heated from room temperature to 700–900°C in an inert atmosphere at a heating rate of 5–15°C / min, and then heated to 1000–1200°C at a heating rate of 1–10°C / min, and held at that temperature for 10–20 hours.

[0035] In another aspect, the present invention provides the use of calcium in improving the reversible hydrogen storage capacity of aluminum-containing hydrogen storage alloys. The aluminum-containing hydrogen storage alloy contains, by molar percentage, 1.8–2 parts La, 1.5–1.8 parts Ce, 2–2.5 parts Y, 20–20.3 parts Ni, 0.5–0.7 parts Mn, and 0.1–0.4 parts Al; and by molar percentage, the amount of calcium in the aluminum-containing hydrogen storage alloy is 0.3–0.6 parts.

[0036] In this invention, the aluminum-containing hydrogen storage alloy has La, Ce, and Y content controlled at appropriate levels on side A, and Ni replaced by specific amounts of Mn and Al on side B, thereby increasing the proportion of hydrogen storage capacity above 0.1 MPa and reducing the hydrogen release plateau pressure. The presence of calcium can improve the reversible hydrogen storage capacity of the aluminum-containing hydrogen storage alloy. Detailed Implementation

[0037] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0038] <Aluminum-containing hydrogen storage alloy>

[0039] The aluminum-containing hydrogen storage alloy of the present invention has a composition represented by formula (1):

[0040] La a Ce b Y c Ca d Ni x Mn y Al z (1).

[0041] Hydrogen storage alloys do not contain Mg, but may contain some unavoidable impurities.

[0042] La is a rare earth element, lanthanum. 'a' represents the molar fraction of La. In this invention, La is a necessary element, and 2 ≥ a ≥ 0.1. In some embodiments, 1.3 ≥ a ≥ 0.8; preferably, 1.1 ≥ a ≥ 1. In other embodiments, 2 ≥ a ≥ 1.8; preferably, 2 ≥ a ≥ 1.9.

[0043] Ce is a rare earth element. b represents the molar fraction of Ce. In this invention, Ce is an essential element, and 2.3 ≥ b ≥ 0.8. In some embodiments, 1.3 ≥ b ≥ 1; preferably, 1.1 ≥ b ≥ 1. In other embodiments, 1.8 ≥ b ≥ 1.5; preferably, 1.6 ≥ b ≥ 1.5.

[0044] In this invention, 3.5 ≥ a + b ≥ 1.5. In some embodiments, 2.2 ≥ a + b ≥ 2. In other embodiments, 3.7 ≥ a + b ≥ 3.5.

[0045] Y is yttrium, a rare earth element. c represents the molar fraction of Y. In this invention, Y is an essential element, and 4.2 ≥ c ≥ 1.8. In some embodiments, 4 ≥ c ≥ 3.5; preferably, 4 ≥ c ≥ 3.8. In other embodiments, 2.5 ≥ c ≥ 2; preferably, 2.2 ≥ c ≥ 2.

[0046] Ca is an alkaline earth metal element. d represents the molar fraction of Ca. In this invention, 1 ≥ d ≥ 0. In some embodiments, d = 0. In other embodiments, 0.6 ≥ d ≥ 0.3; preferably, 0.5 ≥ d ≥ 0.4.

[0047] In this invention, a+b+c+d=6.

[0048] Ni is a metallic element. x represents the molar fraction of Ni. In this invention, Ni is an essential element, and 20.5 ≥ x ≥ 19.5. Preferably, 20.3 ≥ x ≥ 20. In some embodiments, 20.1 ≥ x ≥ 20. In other embodiments, 20.3 ≥ x ≥ 20.2.

[0049] Mn is a metallic element, manganese. y represents the molar fraction of Mn. In this invention, Mn is an essential element, 0.8 ≥ y ≥ 0.4. Preferably, 0.7 ≥ y ≥ 0.5; more preferably, 0.6 ≥ y ≥ 0.5.

[0050] Al is a metallic element, aluminum. z represents the molar fraction of Al. In this invention, Al is an essential element, 0.5 ≥ z ≥ 0.05. Preferably, 0.4 ≥ z ≥ 0.1. In some embodiments, 0.4 ≥ z ≥ 0.3. In other embodiments, 0.2 ≥ z ≥ 0.1.

[0051] In this invention, x+y+z=21.

[0052] Specific embodiments of the aluminum-containing hydrogen storage alloy of the present invention include, but are not limited to, one of the following compositions:

[0053] LaCeY4Ni 20.1 Mn 0.6 Al 0.3 ;

[0054] LaCeY4Ni 20.2 Mn 0.6 Al 0.2 ;

[0055] LaCeY4Ni 20.3 Mn 0.6 Al 0.1 ;

[0056] La 0.6 Ce 1.4 Y4Ni 20.2 Mn 0.6 Al 0.2 ;

[0057] La 0.6 Ce 1.4 Y4Ni 20.3 Mn 0.6 Al 0.1 ;

[0058] La 0.4 Ce 1.6 Y4Ni 20.3 Mn 0.6 Al 0.1 ;

[0059] La 0.2 Ce 1.8 Y4Ni 20.3 Mn 0.6 Al 0.1 ;

[0060] La2CeY3Ni 20.3 Mn 0.6 Al 0.1 ;

[0061] La2Ce 15 Y 25 Ni 203 Mn 06 Al 01 ;

[0062] La2Ce 1.5 Y2Ca 0.5 Ni 20.3 Mn 0.6 Al 0.1 ;

[0063] LaCeY4Ni 20 Mn 0.6 Al 0.4 ;

[0064] La2Ce2Y2N i20.3 Mn 0.6 Al 0.1 .

[0065] In the aluminum-containing hydrogen storage alloy of the present invention, the content of Ce2Ni7 phase is greater than or equal to 55 wt%. The content of Ce2Ni7 phase is less than or equal to 90 wt%. In some embodiments, the content of Ce2Ni7 phase is greater than or equal to 60 wt% and less than or equal to 65 wt%. In other embodiments, the content of Ce2Ni7 phase is greater than or equal to 73 wt% and less than or equal to 77 wt%.

[0066] In addition to the Ce2Ni7 phase, the aluminum-containing hydrogen storage alloy of the present invention also contains the LaNi5 phase and / or Ce5Co phase. 19 Mutually.

[0067] <Preparation Method>

[0068] The preparation method of the aluminum-containing hydrogen storage alloy of the present invention includes the following steps: (1) providing raw materials according to the chemical composition of the hydrogen storage alloy, melting and forming the raw materials to obtain alloy sheets; (2) annealing the alloy sheets in an inert atmosphere to obtain annealed alloy sheets; (3) pulverizing the annealed alloy sheets to obtain aluminum-containing hydrogen storage alloy.

[0069] In step (1), smelting can be carried out under the protection of an inert gas. Smelting can be carried out in a medium-frequency induction furnace.

[0070] In step (1), the rapid quenching process is used to form alloy sheets from the molten alloy.

[0071] In step (2), annealing can be performed in an inert atmosphere. Inert atmospheres include, for example, nitrogen, argon, helium, and neon.

[0072] The annealing process conditions are as follows: the temperature is increased from room temperature to 700-900°C at a heating rate of 5-15°C / min, preferably 8-12°C / min, and more preferably 750-850°C; then the temperature is increased to 1000-1200°C at a heating rate of 1-10°C / min, preferably 3-7°C / min, and more preferably 1050-1100°C, and held for 10-20 hours, preferably 13-17 hours.

[0073] In step (3), the material is pulverized under the protection of an inert gas. The inert gas includes, but is not limited to, nitrogen, argon, helium, and neon.

[0074] Crushing can be achieved through mechanical crushing, grinding, or other methods. In some embodiments, mechanical crushing is performed first, followed by grinding.

[0075] <Uses of calcium>

[0076] This invention discovers that adding an appropriate amount of calcium to aluminum-containing hydrogen storage alloys can improve their reversible hydrogen storage capacity. Therefore, this invention provides a use of calcium in improving the reversible hydrogen storage capacity of aluminum-containing hydrogen storage alloys.

[0077] The aluminum-containing hydrogen storage alloy contains, by molar percentage, 1.8–2 parts La, 1.5–1.8 parts Ce, 2–2.5 parts Y, 20–20.3 parts Ni, 0.5–0.7 parts Mn, and 0.1–0.4 parts Al.

[0078] In aluminum-containing hydrogen storage alloys, the content of La is preferably 1.9 to 2 parts by molar percentage. In some embodiments, the content of La is 2 parts.

[0079] In the aluminum-containing hydrogen storage alloy, the Ce content is preferably 1.5 to 1.6 parts by molar fraction. In some embodiments, the Ce content is 1.5 parts.

[0080] In the aluminum-containing hydrogen storage alloy, the content of Y is preferably 2 to 2.2 parts by molar fraction. In some embodiments, the content of Y is 2 parts.

[0081] In the aluminum-containing hydrogen storage alloy, the Ni content is preferably 20.2 to 20.3 parts by molar percentage. In some embodiments, the Ni content is 20.3 parts.

[0082] In aluminum-containing hydrogen storage alloys, the Mn content is preferably 0.5 to 0.6 parts by molar percentage. In some embodiments, the Mn content is 0.6 parts.

[0083] In aluminum-containing hydrogen storage alloys, the Al content is preferably 0.1 to 0.2 parts by molar percentage. In some embodiments, the Al content is 0.1 parts.

[0084] In the aluminum-containing hydrogen storage alloy, the amount of calcium is 0.3 to 0.6 parts by molar percentage; preferably 0.4 to 0.5 parts.

[0085] The following describes the test methods for the aluminum-containing hydrogen storage alloys obtained in the examples and comparative examples:

[0086] Phase composition and main phase content: Alloy powder with a mesh size smaller than 200 was selected from aluminum-containing hydrogen storage alloys as samples. X-ray diffraction (XRD) patterns were obtained using an X'Pert PRO powder X-ray diffractometer (Cu target, Kα rays) at a power of 40 kV × 40 mA with a step size of 0.01° and a dwell time of 30 s per step. The scanning range was 10–80°. The phase composition and main phase content were determined based on the X-ray diffraction patterns.

[0087] Gaseous hydrogen storage performance: The PCT curve of the aluminum-containing hydrogen storage alloy was determined using a Sievels apparatus. The specific method is as follows: 1.5–1.7 g of the hydrogen storage alloy with a particle size less than 100 mesh was taken and vacuumed at 300°C for 30 min to fully activate the alloy. After cooling to room temperature, the PCT curve was tested at 40°C. The reversible hydrogen storage capacity, hydrogen release plateau pressure, and the percentage of hydrogen stored above 0.1 MPa were obtained from the PCT curve tests.

[0088] Examples 1-12 and Comparative Example 1

[0089] Raw materials were provided according to the chemical composition shown in Table 1. The raw materials were melted in the furnace chamber of a medium-frequency induction melting furnace under inert gas protection to obtain a molten alloy. The molten alloy was then subjected to a rapid quenching process to obtain alloy sheets.

[0090] The alloy sheet was annealed in an argon atmosphere. The specific annealing conditions were as follows: the temperature was increased from room temperature to 800℃ at a rate of 10℃ / min, then increased to 1050℃ at a rate of 5℃ / min, and held at 1050℃ for 16 hours.

[0091] Annealed alloy sheets cooled to room temperature were mechanically crushed and ground under an argon atmosphere to obtain an aluminum-containing hydrogen storage alloy.

[0092] The composition and properties of aluminum-containing hydrogen storage alloys are shown in Table 1.

[0093] Table 1

[0094]

[0095] As can be seen from the XRD pattern, the aluminum-containing hydrogen storage alloy of the present invention consists of Ce2Ni7 phase and Ce5Co phase. 19 It is composed of the LaNi5 phase and the LaNi5 phase.

[0096] As can be seen from Examples 10 and 12, the addition of appropriate calcium can improve the reversible hydrogen storage capacity of aluminum-containing hydrogen storage alloys.

[0097] As can be seen from Examples 1, 2, 3 and 11, the contents of Ni, Mn and Al have a significant impact on the proportion of hydrogen storage capacity above 0.1 MPa and the hydrogen release plateau pressure of aluminum-containing hydrogen storage alloys. Appropriate contents of Ni, Mn and Al, combined with the elements on the A side, can both increase the proportion of hydrogen storage capacity above 0.1 MPa and significantly reduce the hydrogen release plateau pressure.

[0098] This invention is not limited to the above-described embodiments. Any modifications, improvements, or substitutions that can be conceived by those skilled in the art without departing from the essential content of this invention fall within the scope of this invention.

Claims

1. An aluminum-containing hydrogen storage alloy characterized by comprising, having a composition represented by formula (1) Composition: La a Ce b Y c Ca d Ni x Mn y Al z (1) wherein x, y, z, a, b, c, d represent the mole fraction of each element; 1.3≥a≥0.8, 1.3≥b≥0.8, 4.2≥c≥3.8, 1≥d≥0, 20.5≥x≥19.5, 0.8≥y≥0.4, 0.5≥z≥0.2, and a+b+c+d=6, x+y+z=21; The content of the Ce2Ni7 phase in the aluminum-containing hydrogen storage alloy is greater than or equal to 55wt% and less than or equal to 90wt%. The aluminum-containing hydrogen storage alloy further contains LaNi5 phase and / or Ce5Co 19 phase.

2. The aluminum-containing hydrogen storage alloy of claim 1, wherein 1.1≥a≥1, 1.3≥b≥1, 4≥c≥3.

8.

3. The aluminum-containing hydrogen storage alloy of claim 1, wherein 20.3≥x≥20, 0.7≥y≥0.

5.

4. The aluminum-containing hydrogen storage alloy of claim 1, wherein The aluminum-containing hydrogen storage alloy has a composition represented by one of the following formulas: LaCeY4Ni 20.1 Mn 0.6 Al 0.3 ; LaCeY4Ni 20.2 Mn 0.6 Al 0.2 ; LaCeY4Ni 20 Mn 0.6 Al 0.4 .

5. The method of producing an aluminum-containing hydrogen storage alloy according to any one of claims 1 to 4, characterized by, The method comprises the following steps: (1) providing raw materials according to the composition represented by formula (1), melting and forming the raw materials to obtain alloy pieces; (2) annealing the alloy pieces in an inert atmosphere to obtain annealed alloy pieces; (3) pulverizing the annealed alloy pieces to obtain the aluminum-containing hydrogen storage alloy.

6. The production method according to claim 5, characterized by, The annealing of the alloy pieces in an inert atmosphere comprises the following steps: The alloy pieces are heated from room temperature to 700-900℃ at a heating rate of 5-15℃ / min in an inert atmosphere, and then heated to 1000-1200℃ at a heating rate of 1-10℃ / min, and held for 10-20h.

Images