Hydrogen storage alloy, method for producing the same, and use of titanium

Abstract

The application discloses a hydrogen storage alloy, a preparation method thereof and a use of titanium. The hydrogen storage alloy has A2B7 phase as a main phase and has a composition represented by a formula of REaBbCcDxHyTiz a Y b Ti c Ni x Mn y Q z ; wherein RE is selected from at least one element in lanthanide series except Y, and RE must contain La; Q is selected from one or more of Al, V, Cu, Fe and Co; wherein a, b, c, x, y and z respectively represent molar fractions of each element; 1≤a≤4, 1≤b≤4, 0.3≤c≤2.5, 20≤x≤20.5, 0.5≤y≤1, 0≤z≤0.4. The hydrogen storage alloy has a high hydrogen desorption plateau pressure.

Description

TECHNICAL FIELD

[0001] The present application relates to a hydrogen storage alloy and a preparation method thereof and a use of titanium. BACKGROUND

[0002] Hydrogen storage alloys can react with hydrogen to form metal hydride, can absorb and release hydrogen in large quantities and quickly under certain temperature and pressure conditions, and have good reversibility, which is a key material for large-scale development and utilization of hydrogen energy. The traditional AB5-type rare earth hydrogen storage alloy represented by LaNi5 is widely used in commercial applications, but its theoretical hydrogen storage capacity is low, which is difficult to meet the large-scale application and development of hydrogen energy. The AB 3-3.8 type La-Mg-Ni system rare earth hydrogen storage alloy has a greater improvement in hydrogen storage capacity, but the addition of volatile metal Mg in the alloy preparation poses a great safety hazard and increases the difficulty of controlling Mg content and phase composition.

[0003] CN116479287A discloses a hydrogen storage alloy for nickel-hydrogen battery, which has a chemical composition of La 5-x Y x Ni 19-y R y , wherein 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. The hydrogen storage alloy is A5B 19 type, and the hydrogen storage capacity at 0.1 MPa or above is relatively low.

[0004] CN116024459A discloses a superlattice rare earth hydrogen storage material, which has a chemical formula of A a Ce b Y c Ni x Mn y B z , wherein 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, A is one or more selected from La, Pr, Nd, Gd, or Sm containing La, and B is one or more of Al, Cu, Fe, Zn, Co, Si, Zr, Ti; the hydrogen storage material contains 2H type and 3R type (A, Y, Ce)2(Ni, Mn, B)7 phase, and 2H type and 3R type (A, Y, Ce)5(Ni, Mn, B) 19 phase, wherein 40wt%≤(A,Y,Ce)2(Ni,Mn,B)7 phase content≤70wt%, 20wt%≤(A,Y,Ce)5(Ni,Mn,B) 19The phase content is less than or equal to 60 wt%. The rare earth hydrogen storage material B is substituted with Mn and B for Ni, and has a lower hydrogen desorption plateau pressure.

[0005] CN101994030A discloses a rare earth AB5-type hydrogen storage alloy, which is represented by the following general formula: Ml(Ni 1-x-y- w Co x Mn y Al z M w ) m N n . In the formula, x, y, z, w, m, n represent molar ratios, and the numerical ranges are 0 SUMMARY

[0006] Therefore, one object of the present application is to provide a hydrogen storage alloy having a higher hydrogen desorption plateau pressure. Further, the hydrogen storage alloy has a higher reversible hydrogen storage capacity and a hydrogen storage amount ratio of 0.1 MPa or more. Another object of the present application is to provide a preparation method of the hydrogen storage alloy. Still another object of the present application is to provide a use of titanium.

[0007] The above technical objects are achieved by the following technical solutions.

[0008] In one aspect, the present application provides a hydrogen storage alloy, which has a main phase of A2B7 phase and a composition represented by the formula RE a Y b Ti c Ni x Mn y Q z .

[0009] wherein RE is selected from at least one element of lanthanide series excluding Y, and RE must contain La; and Q is selected from one or more of Al, V, Cu, Fe and Co.

[0010] wherein a, b, c, x, y and z represent molar fractions of respective elements; 1≤a≤4, 1≤b≤4, 0.3≤c≤2.5, 20≤x≤20.5, 0.5≤y≤1, 0≤z≤0.4.

[0011] According to the hydrogen storage alloy of the present application, preferably, a+b+c=6, and x+y+z=21.

[0012] According to the hydrogen storage alloy of the present application, preferably, the hydrogen storage alloy further contains a Ni3Ti phase, and the A2B7 phase is a Ce2Ni7 phase.

[0013] According to the hydrogen storage alloy of the present application, preferably, the RE is La, and 1.5≤a≤2.5.

[0014] According to the hydrogen storage alloy of the present application, preferably, the RE is La and Ce, 3≤a≤3.5, and the molar ratio of La and Ce is 2:(0.8-1.8).

[0015] According to the hydrogen storage alloy of the present application, preferably, the Q is selected from one or more of Al and V, and 0.05≤z≤0.3.

[0016] According to the hydrogen storage alloy of the present application, preferably, the hydrogen storage alloy has a reversible hydrogen storage capacity of equal to or greater than 1.4wt%, a hydrogen desorption plateau pressure of equal to or greater than 0.3MPa, and a hydrogen storage amount of equal to or greater than 75wt% at a hydrogen desorption pressure of 0.1MPa or above.

[0017] According to the hydrogen storage alloy of the present application, preferably, the hydrogen storage alloy has a composition as shown in one of the following:

[0018] La2Y 2.5 Ti 1.5 Ni 20.2 Mn 0.8 ;

[0019] La2Y3TiNi 20.2 Mn 0.8 ;

[0020] La2Y 3.5 Ti 0.5 Ni 20.2 Mn 0.8 ;

[0021] La2CeY2TiNi 20.2 Mn 0.8 ;

[0022] La2CeY 2.5 Ti 0.5 Ni 20.2 Mn 0.8 ;

[0023] La2Ce 1.5 Y2Ti 0.5 Ni 20.2 Mn 0.8 ;

[0024] La2Ce 1.5 Y2Ti 0.5 Ni 20.3 Mn 0.6Al 0.1 ;

[0025] La2Ce 1.5 Y2Ti 0.5 Ni 20.3 Mn 0.6 V 0.1 ;

[0026] La2Y2Ti2Ni 20.2 Mn 0.8 ;

[0027] La2CeY 1.5 Ti 1.5 Ni 20.2 Mn 0.8 ;

[0028] La2Ce 1.5 Y 1.5 TiNi 20.2 Mn 0.8 .

[0029] In another aspect, the present application provides a preparation method of the hydrogen storage alloy, comprising the following steps:

[0030] The raw materials provided according to the composition of the hydrogen storage alloy are formed into alloy pieces; the alloy pieces are annealed and then crushed to obtain the hydrogen storage alloy;

[0031] The annealing comprises the following procedures: the alloy pieces are heated from an initial temperature to 650-950℃ at a heating rate of 3-18℃ / min, and then heated to 950-1250℃ at a heating rate of 1-15℃ / min, and kept for 10-20h.

[0032] In still another aspect, the present application provides a use of titanium in improving the hydrogen release plateau pressure of a hydrogen storage alloy, the hydrogen storage alloy comprising 1-4 molar parts of RE, 1-4 molar parts of Y, 20-20.5 molar parts of Ni, 0.5-1 molar parts of Mn, and 0-0.4 molar parts of Q; the RE is selected from at least one element in the lanthanide series excluding Y, and RE must contain La; the Q is selected from one or more of Al, V, Cu, Fe and Co;

[0033] The amount of Ti in the hydrogen storage alloy is 0.3-2.5 molar parts.

[0034] The hydrogen storage alloy of the present application has an appropriate amount of Ti added to the A side, and a Ni3Ti phase is formed in the hydrogen storage alloy, thereby improving the hydrogen release plateau pressure of the hydrogen storage alloy. According to the preferred embodiment of the present application, the elements on the A side and the B side of the hydrogen storage alloy are matched with each other, so that the hydrogen storage alloy has a high hydrogen release plateau pressure, a reversible hydrogen storage capacity and a hydrogen storage amount ratio of 0.1MPa or more. DETAILED DESCRIPTION

[0035] The present application will be further described in conjunction with specific examples, but the scope of the present application is not limited thereto.

[0036] <Hydrogen storage alloy>

[0037] The hydrogen storage alloy of the present application has A2B7 phase as a main phase, and has a composition represented by the formula RE a Y b Ti c Ni x Mn y Q z The hydrogen storage alloy of the present application has A2B7 phase as a main phase, and has a composition represented by the formula RE

[0038] The hydrogen storage alloy of the present application is an A2B7-type La-Y-Ni-based hydrogen storage alloy. The hydrogen storage alloy of the present application does not contain alkali metals and alkaline earth metals. Examples of the alkali metals include, but are not limited to, lithium, sodium, and potassium. Examples of the alkaline earth metals include, but are not limited to, beryllium, magnesium, calcium, strontium, and barium. According to a preferred embodiment of the present application, the hydrogen storage alloy of the present application consists only of RE, Y, Ti, Ni, Mn, and Q, except for inevitable impurities.

[0039] RE represents one or more rare earth elements. RE is selected from at least one element among lanthanide series elements excluding Y, and RE must contain La. In some embodiments, RE is La. In other embodiments, RE is La and Ce. The molar ratio of La and Ce can be 2:(0.8-1.8). In some embodiments, the molar ratio of La and Ce is 2:(1-1.2). In other embodiments, the molar ratio of La and Ce is 2:(1.5-1.6).

[0040] a represents the mole fraction of RE. 1≤a≤4. In some embodiments, 1.5≤a≤2.5; preferably, 2≤a≤2.2. In other embodiments, 3≤a≤3.5. Preferably, 3≤a≤3.2.

[0041] Y represents yttrium element. b represents the mole fraction of Y. 1≤b≤4; preferably, 1.5≤b≤3.5. In some embodiments, 2≤b≤3. In other embodiments, 2.5≤b≤2.7.

[0042] Ti represents titanium element. c represents the mole fraction of Ti. 0.3≤c≤2.5; preferably, 0.5≤c≤2. In some embodiments, 1≤c≤1.5. Controlling Ti to the above content helps the hydrogen storage alloy to have a high hydrogen desorption plateau, reversible hydrogen storage capacity, and a hydrogen storage amount ratio of 0.1 MPa or more.

[0043] In the present application, a+b+c=6.

[0044] Ni represents a nickel element. x represents a mole fraction of nickel. 20 < x < 20.5; preferably, 20.1 < x < 20.4; more preferably, 20.2 < x < 20.3.

[0045] Mn represents a manganese element. y represents a mole fraction of manganese. 0.5 < y < 1; preferably, 0.6 < y < 0.8. In certain embodiments, 0.6 < y < 0.7.

[0046] Q represents a metal element. Q is selected from one or more of Al, V, Cu, Fe, and Co. In certain embodiments, Q is Al. In other embodiments, Q is V.

[0047] z represents a mole fraction of Q. 0 < z < 0.4. In certain embodiments, z = 0. In other embodiments, 0.05 < z < 0.3; preferably, 0.1 < z < 0.2.

[0048] In the present invention, x + y + z = 21.

[0049] In certain embodiments, the hydrogen storage alloy of the present invention has a composition shown in one of the following:

[0050] La2Y 2.5 Ti 1.5 Ni 20.2 Mn 0.8 ;

[0051] La2Y3TiNi 20.2 Mn 0.8 ;

[0052] La2Y 3.5 Ti 0.5 Ni 20.2 Mn 0.8 ;

[0053] La2CeY2TiNi 20.2 Mn 0.8 ;

[0054] La2CeY 2.5 Ti 0.5 Ni 20.2 Mn 0.8 ;

[0055] La2Ce 1.5 Y2Ti 0.5 Ni 20.2 Mn 0.8 ;

[0056] La2Ce 1.5 Y2Ti 0.5 Ni 20.3 Mn 0.6Al 0.1 ;

[0057] La2Ce 1.5 Y2Ti 0.5 Ni 20.3 Mn 0.6 V 0.1 ;

[0058] La2Y2Ti2Ni 20.2 Mn 0.8 ;

[0059] La2CeY 1.5 Ti 1.5 Ni 20.2 Mn 0.8 ;

[0060] La2Ce 1.5 Y 1.5 TiNi 20.2 Mn 0.8 .

[0061] The hydrogen storage alloy of the present application mainly contains A2B7 phase and contains A5B 19 phase, AB5 phase and Ni3Ti phase. In some embodiments, the hydrogen storage alloy of the present application only consists of the above-mentioned phases. The present application adds an appropriate amount of Ti on the A side to form the Ni3Ti phase, thereby improving the hydrogen release plateau pressure of the hydrogen storage alloy. Controlling the content of Ti can make the hydrogen storage alloy have a higher hydrogen release plateau pressure, reversible hydrogen storage capacity and hydrogen storage capacity ratio above 0.1 MPa.

[0062] In the present application, the A2B7 phase is Ce2Ni7 phase. The A5B 19 phase is Ce5Co 19 phase. The AB5 phase is LaNi5.

[0063] The content of the A2B7 phase can be 65-85wt%. In some embodiments, the content of the A2B7 phase is 70-80wt%. In other embodiments, the content of the A2B7 phase is 75-78wt%.

[0064] The hydrogen release plateau pressure of the hydrogen storage alloy of the present application is greater than or equal to 0.3 MPa; preferably, greater than or equal to 0.45 MPa; more preferably, greater than or equal to 0.5 MPa; most preferably, greater than or equal to 0.6 MPa.

[0065] The reversible hydrogen storage capacity of the hydrogen storage alloy of the present application is greater than or equal to 1.4wt%; preferably, greater than or equal to 1.5wt%; more preferably, greater than or equal to 1.6wt%.

[0066] The hydrogen storage alloy of the present application has a hydrogen storage amount of 75wt% or more at 0.1 MPa, preferably 85wt% or more, and more preferably 90wt% or more.

[0067] <Method for preparing the hydrogen storage alloy>

[0068] The method for preparing the hydrogen storage alloy of the present application comprises the following steps: forming an alloy sheet from raw materials provided according to the composition of the hydrogen storage alloy; annealing the alloy sheet, and then crushing to obtain the hydrogen storage alloy.

[0069] The raw materials can be formed into an alloy sheet by high-temperature smelting and rapid quenching. Specifically, the raw materials are smelted to obtain an alloy liquid. The alloy liquid is rapidly quenched to form an alloy sheet. The smelting can be carried out in an inert atmosphere. The smelting can be carried out in a medium-frequency induction smelting furnace.

[0070] The annealing can be carried out in an inert atmosphere. Preferably, the gas providing the inert atmosphere is selected from one or more of nitrogen, argon and helium.

[0071] Specifically, the alloy sheet is heated in an inert atmosphere from an initial temperature to T1 at a heating rate of C1; then heated to T2 at a heating rate of C2, and kept at T2 for t to complete the annealing process. Preferably, after the annealing process, the alloy sheet is cooled to room temperature in the furnace to obtain an annealed alloy sheet.

[0072] The initial temperature can be room temperature. For example, 20-35℃.

[0073] C1 can be 3-18℃ / min; preferably 8-12℃ / min.

[0074] T1 can be 650-950℃; preferably 750-850℃.

[0075] C2 can be 1-15℃ / min; preferably 3-7℃ / min.

[0076] T2 can be 950-1250℃; preferably 1050-1100℃.

[0077] t is 10-20h; preferably 13-17h.

[0078] The crushing can be carried out in an inert atmosphere. Preferably, the gas providing the inert atmosphere is selected from one or more of nitrogen, argon and helium.

[0079] The crushing can be carried out by a combination of mechanical crushing and grinding. The mechanical crushing can be carried out first, followed by the grinding.

[0080] <Use of titanium>

[0081] The present application finds that adding appropriate amount of titanium on the A side of hydrogen storage alloy can form Ni3Ti phase in the hydrogen storage alloy, and improve the hydrogen release platform pressure of the hydrogen storage alloy. Therefore, the present application provides a use of titanium in improving the hydrogen release platform pressure of hydrogen storage alloy.

[0082] The hydrogen storage alloy comprises RE, Y, Ni, Mn and Q. Preferably, the hydrogen storage alloy does not contain alkali metal and alkaline earth metal. Examples of alkali metal include but are not limited to lithium, sodium and potassium. Examples of alkaline earth metal include but are not limited to beryllium, magnesium, calcium, strontium and barium. In some embodiments, the hydrogen storage alloy is composed of the above elements except for inevitable impurities.

[0083] RE represents one or more rare earth elements. RE is selected from at least one element in lanthanide series excluding Y, and RE must contain La. In some embodiments, RE is La. In other embodiments, RE is La and Ce. The molar ratio of La and Ce can be 2:(0.8-1.8). In some embodiments, the molar ratio of La and Ce is 2:(1-1.2). In other embodiments, the molar ratio of La and Ce is 2:(1.5-1.6).

[0084] Q represents a metal element. Q is selected from one or more of Al, V, Cu, Fe and Co. In some embodiments, Q is Al. In other embodiments, Q is V.

[0085] In the hydrogen storage alloy of the present application, the content of RE is 1-4 moles. The content of RE can be represented by a. The value of a is specifically described above and will not be repeated here.

[0086] In the hydrogen storage alloy of the present application, the content of Y is 1-4 moles. The content of Y can be represented by b. The value of b is specifically described above and will not be repeated here.

[0087] In the hydrogen storage alloy of the present application, the content of Ni is 20-20.5 moles. The content of Ni can be represented by x. The value of x is specifically described above and will not be repeated here.

[0088] In the hydrogen storage alloy of the present application, the content of Mn is 0.5-1 moles. The content of Mn can be represented by y. The value of y is specifically described above and will not be repeated here.

[0089] In the hydrogen storage alloy of the present application, the content of Q is 0-0.4 moles. The content of Q can be represented by z. The value of z is specifically described above and will not be repeated here.

[0090] In the hydrogen storage alloy of the present application, the amount of Ti is 0.3-2.5 moles. The amount of Ti can be represented by c. The value of c is specifically described above and will not be repeated here.

[0091] The test method is described as follows:

[0092] The phase composition and main phase content of the hydrogen storage alloy are determined according to the X-ray diffraction spectrum of the hydrogen storage alloy. The method for obtaining the X-ray diffraction spectrum is as follows: the hydrogen storage alloy with a particle size of less than 200 mesh is used as a test sample, and an X'Pert PRO powder X-ray diffractometer (Cu target, Kα ray) is used for testing. The test conditions are as follows: power is 40 kV x 40 mA, step size is 0.01°, each step stays for 30 s, and the scanning range is 10-80°.

[0093] The reversible hydrogen storage capacity, hydrogen release platform pressure and hydrogen storage amount ratio above 0.1 MPa of the hydrogen storage alloy are obtained according to the P-C-T curve. The P-C-T curve of the hydrogen storage alloy is obtained by the following method: the hydrogen storage alloy with a particle size of less than 100 mesh is used as a test sample, and the amount of the test sample is 1.5-1.7 g. The test sample is vacuumized at 300 ℃ for 30 min, and then cooled to room temperature to obtain an activated sample. The activated sample is tested by a Sievelts device at 40 ℃ to obtain the P-C-T curve of the hydrogen storage alloy.

[0094] Examples 1 to 11

[0095] The raw materials provided according to the composition of the hydrogen storage alloy shown in Table 1 are melted in a medium-frequency induction melting furnace in an inert atmosphere to obtain an alloy liquid. The alloy liquid is rapidly quenched to form an alloy sheet.

[0096] The alloy sheet is heated to 800 ℃ at a heating rate of 10 ℃ / min from room temperature in an argon atmosphere, and then heated to 1050 ℃ at a heating rate of 5 ℃ / min, and the annealing process is completed at 1050 ℃ for 16 h, and then cooled to room temperature in the furnace to obtain an annealed alloy sheet.

[0097] The annealed alloy sheet is first mechanically broken and then ground in an argon atmosphere to obtain a hydrogen storage alloy.

[0098] The composition of the hydrogen storage alloy is shown in Table 1. The hydrogen storage performance of the hydrogen storage alloy is shown in Table 1.

[0099] According to the X-ray diffraction spectrum of the hydrogen storage alloy obtained from Examples 1-11, the hydrogen storage alloy obtained from Examples 1-11 is composed of Ce2Ni7 phase, Ni3Ti phase, Ce5Co 19 phase and LaNi5 phase, and the Ce2Ni7 phase is the main phase. The content of the Ce2Ni7 phase is shown in Table 1.

[0100] Table 1

[0101]

[0102] It can be seen from Examples 1-4, 5-7, 8 and 11 that Ti can improve the hydrogen release plateau pressure of the hydrogen storage alloy, but excessive Ti content can reduce the reversible hydrogen storage capacity and the proportion of hydrogen storage capacity above 0.1 MPa.

[0103] It can be seen from Examples 1 and 7, 2 and 5, and 3 and 6 that replacing part of Y with Ce can improve the reversible hydrogen storage capacity and the hydrogen release plateau pressure of the hydrogen storage alloy.

[0104] It can be seen from Examples 6 and 8 that excessive Ce content can reduce the reversible hydrogen storage capacity.

[0105] It can be seen from Examples 8 and 9 that the addition of Al can improve the proportion of hydrogen storage capacity above 0.1 MPa, but can reduce the reversible hydrogen storage capacity and the hydrogen release plateau pressure.

[0106] It can be seen from Examples 8 and 10 that the addition of V can help to improve the reversible hydrogen storage capacity and the hydrogen release plateau pressure, but can reduce the proportion of hydrogen storage capacity above 0.1 MPa.

[0107] The present application is not limited to the above-mentioned embodiments, and any modifications, improvements, replacements that can be conceived by those skilled in the art without departing from the essential content of the present application fall within the scope of the present application.

Claims

1. A hydrogen storage alloy characterized by comprising: The hydrogen storage alloy has A2B7 phase as a main phase, and has a composition represented by the formula RE a Y b Ti c Ni x Mn y Q z ​ wherein RE is selected from at least one element of lanthanide series excluding Y, and RE must contain La; Q is selected from one or more of Al, V, Cu, Fe and Co; wherein a, b, c, x, y and z represent molar fractions of respective elements; 1≤a≤4, 1≤b≤3, 1.5≤c≤2.5, 20≤x≤20.5, 0.5≤y≤1, 0≤z≤0.4; a+b+c=6, x+y+z=21; The content of the A2B7 phase is 75-85wt%, and the hydrogen desorption plateau pressure of the hydrogen storage alloy is greater than or equal to 0.6MPa.

2. The hydrogen storage alloy according to claim 1, characterized by The hydrogen storage alloy further contains a Ni3Ti phase, and the A2B7 phase is a Ce2Ni7 phase.

3. The hydrogen storage alloy according to claim 1, wherein The RE is La, and 1.5≤a≤2.

5.

4. The hydrogen storage alloy according to claim 1, wherein The RE is La and Ce, 3≤a≤3.5, and the molar ratio of La to Ce is 2:(0.8-1.8).

5. The hydrogen storage alloy according to claim 1, wherein The Q is selected from one or more of Al and V, and 0.05≤z≤0.

3.

6. The hydrogen storage alloy according to claim 1, wherein The reversible hydrogen storage capacity of the hydrogen storage alloy is greater than or equal to 1.4wt%, and the hydrogen storage amount at 0.1MPa accounts for greater than or equal to 75wt%.

7. The hydrogen storage alloy according to any one of claims 1 to 6, characterized by, The hydrogen storage alloy has a composition shown in one of the following: La2Y 2.5 Ti 1.5 Ni 20.2 Mn 0.8 ; La2Y2Ti2Ni 20.2 Mn 0.8 ; La2CeY 1.5 Ti 1.5 Ni 20.2 Mn 0.8 .

8. The method of claim 1 to 7, wherein The method comprises the following steps: Providing raw materials according to the composition of the hydrogen storage alloy, forming an alloy sheet, annealing the alloy sheet, and then crushing to obtain the hydrogen storage alloy; The annealing comprises the following procedures: heating the alloy sheet from an initial temperature to 650-950℃ at a heating rate of 3-18℃ / min, then heating to 950-1250℃ at a heating rate of 1-15℃ / min, and maintaining for 10-20h.

9. Use of titanium for increasing the hydrogen desorption plateau pressure of a hydrogen storage alloy, characterized in that, The hydrogen storage alloy is composed of 1-4mol% of RE, 1-3mol% of Y, 20-20.5mol% of Ni, 0.5-1mol% of Mn, 0-0.4mol% of Q, and 0.3-2.5mol% of Ti; the RE is selected from at least one element of lanthanide series excluding Y, and RE must contain La; the Q is selected from one or more of Al, V, Cu, Fe and Co; The sum of the molar fraction of RE, the molar fraction of Y and the molar fraction of Ti is 6, and the sum of the molar fraction of Ni, the molar fraction of Mn and the molar fraction of Q is 21; The content of the A2B7 phase in the hydrogen storage alloy is 75-85wt%, and the hydrogen desorption plateau pressure of the hydrogen storage alloy is greater than or equal to 0.6MPa.

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