A two-phase superlattice hydrogen storage alloy, a preparation method thereof and a hydrogen storage system

Abstract

The application belongs to the technical field of hydrogen storage alloys, and particularly relates to a dual-phase superlattice hydrogen storage alloy, a preparation method thereof and a hydrogen storage system. 1‑a‑b Mg a Sc b Ni x Mn y M z , wherein M comprises at least one of Cr, V, Co, Mo and W, 0.1<=a<=0.15, 0.02<=b<=0.08, 2.8<=x<=3.1, 0<y<=0.15, and 0<=z<=0.1. The dual-phase superlattice hydrogen storage alloy has AB3 phase and A2B7 phase, and compared with the currently widely used AB5 type rare earth hydrogen storage alloy, the dual-phase superlattice hydrogen storage alloy exhibits excellent hydrogen storage capacity and high cycle stability, the hydrogen absorption capacity at normal temperature can reach more than 1.55wt%, the effective hydrogen release capacity at normal temperature can reach more than 1.5wt%, and the cycle stability can reach more than 97%.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of hydrogen storage alloys, and particularly relates to a dual-phase superlattice hydrogen storage alloy, a preparation method thereof and a hydrogen storage system. BACKGROUND

[0002] Among existing rare earth-based hydrogen storage materials, CaCu5 type (AB5 type) alloys have excellent cycle stability, but their theoretical hydrogen storage capacity is low, which is difficult to meet the needs of high energy density applications. Therefore, researchers have proposed rare earth-based hydrogen storage alloys with superlattice structures. Such superlattice structures are usually composed of [A2B4] and [AB5] subunits stacked along the c-axis in different proportions. Generally, the [A2B4] subunit has a higher contribution to hydrogen storage capacity, but has poor cycle stability, while the [AB5] subunit has good structural stability, but limits the improvement of the overall hydrogen storage capacity. Therefore, the comprehensive performance of superlattice hydrogen storage alloys depends largely on the stacking ratio of the two subunits and their structural coordination.

[0003] Although the hydrogen storage capacity of superlattice alloys is generally higher than that of traditional AB5 type alloys, their cycle stability is still insufficient, which restricts their popularization in engineering applications. Among existing superlattice structures, AB3 type alloys have higher theoretical hydrogen storage capacity due to the higher proportion of [A2B4] subunits, and thus have potential in improving energy density. However, AB3 type alloys still have deficiencies in cycle stability and plateau pressure control.

[0004] Therefore, how to improve the cycle stability and actual effective hydrogen storage capacity of AB3 type alloys while maintaining their high hydrogen storage capacity advantage has become a key technical problem to be solved. SUMMARY

[0005] In a first aspect, the present application provides a dual-phase superlattice hydrogen storage alloy, the chemical general formula of which is: Y 1-a-b Mg a Sc b Ni x Mn y M z wherein M includes at least one of Cr, V, Co, Mo and W, 0.1≤a≤0.15, 0.02≤b≤0.08, 2.8≤x≤3.1, 0

[0006] The inventors found that the introduction of Sc element is of critical significance. Since the atomic radius of Sc (162 pm) is significantly smaller than that of Y (180 pm), the doping of Sc can induce a lattice local shrinkage effect, shrink the [A2B4] subunit and better match the lattice parameters of the [AB5] subunit, thereby reducing the stress accumulation between the subunits and improving the structural stability. In addition, the difference in electronegativity of Sc also helps to optimize the electron distribution and improve the reaction kinetics in the hydrogen absorption / desorption process. On this basis, the further introduction of M element can stabilize the alloy structure and help to regulate the diffusion path and activation energy of hydrogen in the lattice, thereby improving the cycle life and hydrogen desorption platform stability.

[0007] In the present application, the proportion of Sc element in the dual-phase superlattice hydrogen storage alloy is 0.02≤b≤0.08, for example, it can be 0.02, 0.03, 0.04, 0.05, 0.06, 0.07 or 0.08, etc.; the proportion of M element in the dual-phase superlattice hydrogen storage alloy is 0≤z≤0.1, for example, it can be 0, 0.01, 0.02, 0.04, 0.06, 0.08 or 0.1, etc.; the proportion of Mg element in the dual-phase superlattice hydrogen storage alloy is 0.1≤a≤0.15, for example, it can be 0.1, 0.11, 0.12, 0.13, 0.14 or 0.15, etc.; the proportion of Ni element in the dual-phase superlattice hydrogen storage alloy is 2.8≤x≤3.1, for example, it can be 2.8, 2.85, 2.9, 2.95, 3.0, 3.05 or 3.1, etc.; the proportion of Mn element in the dual-phase superlattice hydrogen storage alloy is 0

[0008] In some preferred embodiments, M is at least one of Cr and Co.

[0009] In some preferred embodiments, 0.11≤a≤0.15, 0.03≤b≤0.06, 2.85≤x≤3.1, 0.08≤y≤0.12, 0≤z≤0.08.

[0010] In some more preferred embodiments, a=0.15, 0.05≤b≤0.06, 2.85≤x≤3.1, 0.08≤y≤0.12, 0.07≤z≤0.08.

[0011] In some embodiments, the hydrogen absorption amount of the dual-phase superlattice hydrogen storage alloy at room temperature is >1.55wt%, the effective hydrogen desorption amount of the dual-phase superlattice hydrogen storage alloy at room temperature is ≥1.5wt%, and the room temperature is 25℃.

[0012] In the present application, the plateau pressure of the hydrogen storage alloy during hydrogen absorption and desorption is ≥0.1 MPa, which can ensure the effective hydrogen desorption amount in practical application.

[0013] In some embodiments, the structural phase of the dual-phase superlattice hydrogen storage alloy is AB3 phase and A2B7 phase.

[0014] In some preferred embodiments, the main phase of the dual-phase superlattice hydrogen storage alloy is AB3 phase.

[0015] In some embodiments, the dual-phase superlattice hydrogen storage alloy comprises Y 0.84 Mg 0.13 Sc 0.03 Ni 3.1 Mn 0.1 , Y 0.8 3Mg 0.12 Sc 0.05 Ni 3.05 Mn 0.1 V 0.05 , Y 0.79 Mg 0.15 Sc 0.06 Ni 3.1 Mn 0.08 Cr 0.07 , Y 0.8 Mg 0.15 Sc 0.05 Ni 2.85 Mn 0.12 Co 0. 08 , Y 0.81 Mg 0.15 Sc 0.04 Ni 2.95 Mn 0.11 Mo 0.06 and Y 0.86 Mg 0.11 Sc 0.03 Ni 3.02 Mn 0.08 W 0.05 .

[0016] In the second aspect of the present application, a preparation method of the dual-phase superlattice hydrogen storage alloy is provided, which comprises the following steps: taking raw materials according to the stoichiometric ratio of the general formula Y 1-a-b Mg a Sc b Ni x Mn y M z , and then performing melting and annealing treatment to obtain the dual-phase superlattice hydrogen storage alloy.

[0017] In some embodiments, the melting is performed by using a medium-frequency induction melting method.

[0018] In some embodiments, the step of the annealing treatment comprises: increasing the temperature from room temperature to 600-700℃ at a temperature increasing rate of 5-10℃ / min, then increasing the temperature to 800-900℃ at a temperature increasing rate of 1-3℃ / min, and then increasing the temperature to 900-1100℃ at a temperature increasing rate of 1-3℃ / min, maintaining for 6-12h, and cooling.

[0019] In a third aspect, the present application provides a hydrogen storage device comprising the dual-phase superlattice hydrogen storage alloy.

[0020] In a fourth aspect, the present application provides a hydrogen storage system comprising the hydrogen storage device.

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] (1) The present application introduces Sc element with smaller atomic radius on the A side to realize directional contraction of [A2B4] subunit, reduce the volume difference of subunit, and better match the lattice parameters of [AB5] subunit, thereby reducing the stress accumulation between subunits and improving the structural stability. In addition, the difference in electronegativity of Sc also helps to optimize the electron distribution and improve the reaction kinetics during the hydrogen absorption / desorption process, so that the alloy has excellent cycle stability and hydrogen storage capacity. Further, by introducing M element, the alloy structure can be stabilized, which helps to control the diffusion path and activation energy of hydrogen in the lattice, further improving the cycle life and hydrogen desorption platform stability, so that the hydrogen absorption amount of the alloy can be up to 1.68 wt%, the effective hydrogen desorption amount can be up to 1.59 wt%, and the capacity retention rate can be up to 98.5%.

[0023] (2) The dual-phase superlattice hydrogen storage alloy of the present application has AB3 phase and A2B7 phase as structural phases. Compared with the widely used AB5 type rare earth hydrogen storage alloy, the dual-phase superlattice hydrogen storage alloy of the present application exhibits excellent hydrogen storage capacity and high cycle stability, with hydrogen absorption amount of more than 1.55 wt% at room temperature, effective hydrogen desorption amount of more than 1.5 wt%, and cycle stability of more than 97%, which provides a new solution for developing high-performance rare earth-based hydrogen storage materials. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 Pressure-composition-temperature (PCT) curves of Examples 1-3 and Comparative Example 1. DETAILED DESCRIPTION

[0025] The application will be further described in details by specific examples, which do not represent the limitation of the protection scope of the application. Some non-essential modifications and adjustments made by others according to the concept of the application still belong to the protection scope of the application. The raw materials, reagents or devices used in the examples can be obtained from conventional commercial channels or can be obtained by the prior art methods. Unless otherwise specified, the test or test method is the conventional method in the art.

[0026] The raw materials used in the examples and comparative examples of the application include metal elements Y, Mg, Sc, Ni, Mn, V, Cr, Co, Mo, W, Pr, Gd, Tb, Pd and In.

[0027] Example 1: Y 0.84 Mg 0.13 Sc 0.03 Ni 3.1 Mn 0.1

[0028] Preparation of hydrogen storage alloy: according to the atomic ratio of the alloy design composition, the corresponding metal elements Y, Mg, Sc, Ni and Mn are weighed as raw materials, the weighed raw materials are put into the crucible of the intermediate frequency induction furnace, the induction furnace is subjected to vacuum gas washing operation, then argon is filled for melting, in order to ensure uniform alloy melting, the cast alloy is obtained after 3 times of melting. The cast alloy is wrapped with tantalum sheet and sealed in a quartz tube filled with argon, and argon is filled in the quartz tube as protective gas, then the quartz tube is put into a muffle furnace for annealing; the annealing process is as follows: the temperature is raised from room temperature to 650℃ at a rate of 7℃ / min, then the temperature is raised to 850℃ at a rate of 2℃ / min, then the temperature is raised to 950℃ at a rate of 1℃ / min, after 8h of heat preservation, it is naturally cooled to room temperature and taken out, thereby the dual-phase superlattice hydrogen storage alloy is prepared.

[0029] Example 2: Y 0.83 Mg 0.12 Sc 0.05 Ni 3.05 Mn 0.1 V 0.05

[0030] Preparation of hydrogen storage alloy: according to the atomic ratio of the alloy design components, the corresponding metal elements Y, Mg, Sc, Ni, Mn, V are taken as raw materials, the weighed raw materials are put into the crucible of the intermediate frequency induction furnace, the induction furnace is vacuumed and washed with gas, then argon is filled for smelting, in order to ensure the uniformity of alloy smelting, the cast alloy is obtained after smelting for 3 times. The cast alloy is wrapped with tantalum sheet and sealed in a quartz tube filled with argon, and argon is filled as protective gas in the quartz tube, then the quartz tube is put into a muffle furnace for annealing; the annealing process is as follows: the temperature is raised from room temperature to 650℃ at a rate of 7℃ / min, then the temperature is raised to 850℃ at a rate of 2℃ / min, then the temperature is raised to 965℃ at a rate of 1℃ / min, after 8h of heat preservation, it is naturally cooled to room temperature and taken out, and the said dual-phase superlattice hydrogen storage alloy is prepared.

[0031] Example 3: Y 0.79 Mg 0.15 Sc 0.06 Ni 3.1 Mn 0.08 Cr 0.07

[0032] Preparation of hydrogen storage alloy: according to the atomic ratio of the alloy design components, the corresponding metal elements Y, Mg, Sc, Ni, Mn, Cr are taken as raw materials, the weighed raw materials are put into the crucible of the intermediate frequency induction furnace, the induction furnace is vacuumed and washed with gas, then argon is filled for smelting, in order to ensure the uniformity of alloy smelting, the cast alloy is obtained after smelting for 3 times. The cast alloy is wrapped with tantalum sheet and sealed in a quartz tube filled with argon, and argon is filled as protective gas in the quartz tube, then the quartz tube is put into a muffle furnace for annealing; the annealing process is as follows: the temperature is raised from room temperature to 650℃ at a rate of 7℃ / min, then the temperature is raised to 850℃ at a rate of 2℃ / min, then the temperature is raised to 1010℃ at a rate of 1℃ / min, after 8h of heat preservation, it is naturally cooled to room temperature and taken out, and the said dual-phase superlattice hydrogen storage alloy is prepared.

[0033] Example 4: Y 0.8 Mg 0.15 Sc 0.05 Ni 2.85 Mn 0.12 Co 0.08

[0034] Preparation of hydrogen storage alloy: according to the atomic ratio of the alloy design components, the corresponding metal elements Y, Mg, Sc, Ni, Mn, Co are taken as raw materials, the weighed raw materials are put into the crucible of the intermediate frequency induction furnace, the induction furnace is vacuumed and washed with gas, then argon is filled for smelting, in order to ensure uniform alloy smelting, the cast alloy is obtained after smelting for 3 times. The cast alloy is wrapped with tantalum sheet and sealed in a quartz tube filled with argon, argon is filled as protective gas in the quartz tube, then the quartz tube is put into a muffle furnace for annealing; the annealing process is as follows: the temperature is raised from room temperature to 650℃ at a rate of 7℃ / min, then raised to 850℃ at a rate of 2℃ / min, then raised to 975℃ at a rate of 1℃ / min, after 8h of heat preservation, it is naturally cooled to room temperature and taken out, thereby the dual-phase superlattice hydrogen storage alloy is prepared.

[0035] Example 5: Y 0.81 Mg 0.15 Sc 0.04 Ni 2.95 Mn 0.11 Mo 0.06

[0036] Preparation of hydrogen storage alloy: according to the atomic ratio of the alloy design components, the corresponding metal elements Y, Mg, Sc, Ni, Mn, Mo are taken as raw materials, the weighed raw materials are put into the crucible of the intermediate frequency induction furnace, the induction furnace is vacuumed and washed with gas, then argon is filled for smelting, in order to ensure uniform alloy smelting, the cast alloy is obtained after smelting for 3 times. The cast alloy is wrapped with tantalum sheet and sealed in a quartz tube filled with argon, argon is filled as protective gas in the quartz tube, then the quartz tube is put into a muffle furnace for annealing; the annealing process is as follows: the temperature is raised from room temperature to 650℃ at a rate of 7℃ / min, then raised to 850℃ at a rate of 2℃ / min, then raised to 975℃ at a rate of 1℃ / min, after 8h of heat preservation, it is naturally cooled to room temperature and taken out, thereby the dual-phase superlattice hydrogen storage alloy is prepared.

[0037] Example 6: Y 0.86 Mg 0.11 Sc 0.03 Ni 3.02 Mn 0.08 W 0.05

[0038] Preparation of hydrogen storage alloy: according to the atomic ratio of the alloy design component, the corresponding metal elements Y, Mg, Sc, Ni, Mn and W were weighed as raw materials, the weighed raw materials were put into the crucible of the intermediate frequency induction furnace, the induction furnace was vacuumed and washed with gas, then argon was filled for smelting, in order to ensure uniform smelting of the alloy, the cast alloy was obtained after smelting for 3 times. The cast alloy was wrapped with tantalum sheet and sealed in a quartz tube filled with argon, argon was filled as protective gas in the quartz tube, then the quartz tube was put into a muffle furnace for annealing; the annealing process is as follows: the temperature is raised from room temperature to 650℃ at a rate of 7℃ / min, then raised to 850℃ at a rate of 2℃ / min, then raised to 985℃ at a rate of 1℃ / min, after 8h of heat preservation, it is naturally cooled to room temperature and taken out, thereby the dual-phase superlattice hydrogen storage alloy is prepared.

[0039] Comparative Example 1: Y 0.87 Mg 0.13 Ni 3.1 Mn 0.1

[0040] Preparation of hydrogen storage alloy: according to the atomic ratio of the alloy design component, the corresponding metal elements Y, Mg, Sc, Ni, Mn and W were weighed as raw materials, the weighed raw materials were put into the crucible of the intermediate frequency induction furnace, the induction furnace was vacuumed and washed with gas, then argon was filled for smelting, in order to ensure uniform smelting of the alloy, the cast alloy was obtained after smelting for 3 times. The cast alloy was wrapped with tantalum sheet and sealed in a quartz tube filled with argon, argon was filled as protective gas in the quartz tube, then the quartz tube was put into a muffle furnace for annealing; the annealing process is as follows: the temperature is raised from room temperature to 650℃ at a rate of 7℃ / min, then raised to 850℃ at a rate of 2℃ / min, then raised to 985℃ at a rate of 1℃ / min, after 8h of heat preservation, it is naturally cooled to room temperature and taken out, thereby the dual-phase superlattice hydrogen storage alloy is prepared.

[0041] Comparative Example 2: Y 0.86 Mg 0.13 Sc 0.01 Ni 3.1 Mn 0.1

[0042] Preparation of hydrogen storage alloy: according to the atomic ratio of the alloy design composition, the corresponding metal elements Y, Mg, Sc, Ni and Mn were weighed as raw materials, the weighed raw materials were put into the crucible of the intermediate frequency induction furnace, the induction furnace was vacuumed and washed with gas, then argon was filled for smelting, in order to ensure uniform smelting of the alloy, the cast alloy was obtained after smelting for 3 times. The cast alloy was wrapped with tantalum sheet and sealed in a quartz tube filled with argon, argon was filled as protective gas in the quartz tube, then the quartz tube was put into a muffle furnace for annealing; the annealing process is as follows: the temperature is raised from room temperature to 650℃ at a rate of 7℃ / min, then raised to 850℃ at a rate of 2℃ / min, then raised to 960℃ at a rate of 1℃ / min, after 8h of heat preservation, it is naturally cooled to room temperature and taken out, and the hydrogen storage alloy is prepared.

[0043] Comparative Example 3: Y 0.77 Mg 0.13 Sc 0.1 Ni 3.1 Mn 0.1

[0044] Preparation of hydrogen storage alloy: according to the atomic ratio of the alloy design composition, the corresponding metal elements Y, Mg, Sc, Ni and Mn were weighed as raw materials, the weighed raw materials were put into the crucible of the intermediate frequency induction furnace, the induction furnace was vacuumed and washed with gas, then argon was filled for smelting, in order to ensure uniform smelting of the alloy, the cast alloy was obtained after smelting for 3 times. The cast alloy was wrapped with tantalum sheet and sealed in a quartz tube filled with argon, argon was filled as protective gas in the quartz tube, then the quartz tube was put into a muffle furnace for annealing; the annealing process is as follows: the temperature is raised from room temperature to 650℃ at a rate of 7℃ / min, then raised to 850℃ at a rate of 2℃ / min, then raised to 960℃ at a rate of 1℃ / min, after 8h of heat preservation, it is naturally cooled to room temperature and taken out, and the hydrogen storage alloy is prepared.

[0045] Comparative Example 4: Y 0.84 Mg 0.13 Pr 0.03 Ni 3.1 Mn 0.1

[0046] Preparation of hydrogen storage alloy: according to the atomic ratio of the alloy design composition, the corresponding metal elements Y, Mg, Pr, Ni and Mn were weighed as raw materials, the weighed raw materials were put into the crucible of the intermediate frequency induction furnace, the induction furnace was vacuumed and washed with gas, then argon was filled for smelting, in order to ensure uniform smelting of the alloy, the cast alloy was obtained after smelting for 3 times. The cast alloy was wrapped with tantalum sheet and sealed in a quartz tube filled with argon, argon was filled as protective gas in the quartz tube, then the quartz tube was put into a muffle furnace for annealing; the annealing process is as follows: the temperature is raised from room temperature to 650℃ at a rate of 7℃ / min, then raised to 850℃ at a rate of 2℃ / min, then raised to 985℃ at a rate of 1℃ / min, after 8h of heat preservation, it is naturally cooled to room temperature and taken out, and the hydrogen storage alloy is prepared.

[0047] Comparative Example 5: Y 0.84 Mg 0.13 Gd 0.03 Ni 3.2 Mn 0.1

[0048] Preparation of hydrogen storage alloy: according to the atomic ratio of the alloy design composition, the corresponding metal elements Y, Mg, Pr, Ni and Mn were weighed as raw materials, the weighed raw materials were put into the crucible of the intermediate frequency induction furnace, the induction furnace was vacuumed and washed with gas, then argon was filled for smelting, in order to ensure uniform smelting of the alloy, the cast alloy was obtained after smelting for 3 times. The cast alloy was wrapped with tantalum sheet and sealed in a quartz tube filled with argon, argon was filled as protective gas in the quartz tube, then the quartz tube was put into a muffle furnace for annealing; the annealing process is as follows: the temperature is raised from room temperature to 650℃ at a rate of 7℃ / min, then raised to 850℃ at a rate of 2℃ / min, then raised to 985℃ at a rate of 1℃ / min, after 8h of heat preservation, it is naturally cooled to room temperature and taken out, and the hydrogen storage alloy is prepared.

[0049] Comparative Example 6: Y 0.84 Mg 0.13 Tb 0.03 Ni 3.1 Mn 0.1

[0050] Preparation of hydrogen storage alloy: according to the atomic ratio of the alloy design composition, the corresponding metal elements Y, Mg, Tb, Ni and Mn were weighed as raw materials, the weighed raw materials were put into the crucible of the intermediate frequency induction furnace, the induction furnace was vacuumed and washed with gas, then argon was filled for smelting, in order to ensure uniform smelting of the alloy, the cast alloy was obtained after smelting for 3 times. The cast alloy was wrapped with tantalum sheet and sealed in a quartz tube filled with argon, argon was filled as protective gas in the quartz tube, then the quartz tube was put into a muffle furnace for annealing; the annealing process is as follows: the temperature is raised from room temperature to 650℃ at a rate of 7℃ / min, then raised to 850℃ at a rate of 2℃ / min, then raised to 1025℃ at a rate of 1℃ / min, after 8h of heat preservation, it is naturally cooled to room temperature and taken out, and the hydrogen storage alloy is prepared.

[0051] Comparative Example 7: Y 0.77 Mg 0.20 Sc 0.03 Ni 3.1 Mn 0.1

[0052] Preparation of hydrogen storage alloy: according to the atomic ratio of the alloy design composition, the corresponding metal elements Y, Mg, Sc, Ni and Mn were weighed as raw materials, the weighed raw materials were put into the crucible of the intermediate frequency induction furnace, the induction furnace was vacuumed and washed with gas, then argon was filled for smelting, in order to ensure uniform smelting of the alloy, the cast alloy was obtained after smelting for 3 times. The cast alloy was wrapped with tantalum sheet and sealed in a quartz tube filled with argon, argon was filled as protective gas in the quartz tube, then the quartz tube was put into a muffle furnace for annealing; the annealing process is as follows: the temperature is raised from room temperature to 650℃ at a rate of 7℃ / min, then raised to 850℃ at a rate of 2℃ / min, then raised to 980℃ at a rate of 1℃ / min, after 8h of heat preservation, it is naturally cooled to room temperature and taken out, and the hydrogen storage alloy is prepared.

[0053] Comparative Example 8: Y 0.92 Mg 0.05 Sc 0.03 Ni 3.1 Mn 0.1

[0054] Preparation of hydrogen storage alloy: according to the atomic ratio of the alloy design composition, the corresponding metal elements Y, Mg, Sc, Ni and Mn were weighed as raw materials, the weighed raw materials were put into the crucible of the intermediate frequency induction furnace, the induction furnace was vacuumed and washed with gas, then argon was filled for smelting, in order to ensure uniform smelting of the alloy, the cast alloy was obtained after smelting for 3 times. The cast alloy was wrapped with tantalum sheet and sealed in a quartz tube filled with argon, argon was filled as protective gas in the quartz tube, then the quartz tube was put into a muffle furnace for annealing; the annealing process is as follows: the temperature is raised from room temperature to 650℃ at a rate of 7℃ / min, then raised to 850℃ at a rate of 2℃ / min, then raised to 985℃ at a rate of 1℃ / min, after 8h of heat preservation, it is naturally cooled to room temperature and taken out, and the hydrogen storage alloy is prepared.

[0055] Comparative example 9: Y 0.84 Mg 0.13 Sc 0.03 Ni 3.1 Mn 0.2

[0056] Preparation of hydrogen storage alloy: according to the atomic ratio of the alloy design composition, the corresponding metal elements Y, Mg, Sc, Ni and Mn were weighed as raw materials, the weighed raw materials were put into the crucible of the intermediate frequency induction furnace, the induction furnace was vacuumed and washed with gas, then argon was filled for smelting, in order to ensure uniform smelting of the alloy, the cast alloy was obtained after smelting for 3 times. The cast alloy was wrapped with tantalum sheet and sealed in a quartz tube filled with argon, argon was filled as protective gas in the quartz tube, then the quartz tube was put into a muffle furnace for annealing; the annealing process is as follows: the temperature is raised from room temperature to 650℃ at a rate of 7℃ / min, then raised to 850℃ at a rate of 2℃ / min, then raised to 1050℃ at a rate of 1℃ / min, after 8h of heat preservation, it is naturally cooled to room temperature and taken out, and the hydrogen storage alloy is prepared.

[0057] Comparative example 10: Y 0.84 Mg 0.13 Sc 0.03 Ni 3.1

[0058] Preparation of hydrogen storage alloy: according to the atomic ratio of the alloy design composition, the corresponding metal elements Y, Mg, Sc, Ni were weighed as raw materials, the weighed raw materials were put into the crucible of the intermediate frequency induction furnace, the induction furnace was vacuumed and washed with gas, then argon was filled for smelting, in order to ensure uniform alloy smelting, the cast alloy was obtained after smelting for 3 times. The cast alloy was wrapped with tantalum sheet and sealed in a quartz tube filled with argon, and argon was filled as protective gas in the quartz tube, then the quartz tube was put into a muffle furnace for annealing; the annealing process is as follows: the temperature is raised from room temperature to 650℃ at a rate of 7℃ / min, then the temperature is raised to 850℃ at a rate of 2℃ / min, then the temperature is raised to 950℃ at a rate of 1℃ / min, after 8h of heat preservation, it is naturally cooled to room temperature and taken out, and the hydrogen storage alloy is prepared.

[0059] Comparative example 11: Y 0.84 Mg 0.13 Sc 0.03 Ni 3.1 Mn 0.1 Pd 0.05

[0060] Preparation of hydrogen storage alloy: according to the atomic ratio of the alloy design composition, the corresponding metal elements Y, Mg, Sc, Ni, Mn, Pd were weighed as raw materials, the weighed raw materials were put into the crucible of the intermediate frequency induction furnace, the induction furnace was vacuumed and washed with gas, then argon was filled for smelting, in order to ensure uniform alloy smelting, the cast alloy was obtained after smelting for 3 times. The cast alloy was wrapped with tantalum sheet and sealed in a quartz tube filled with argon, and argon was filled as protective gas in the quartz tube, then the quartz tube was put into a muffle furnace for annealing; the annealing process is as follows: the temperature is raised from room temperature to 650℃ at a rate of 7℃ / min, then the temperature is raised to 850℃ at a rate of 2℃ / min, then the temperature is raised to 960℃ at a rate of 1℃ / min, after 8h of heat preservation, it is naturally cooled to room temperature and taken out, and the hydrogen storage alloy is prepared.

[0061] Comparative example 12: Y 0.84 Mg 0.13 Sc 0.03 Ni 3.1 Mn 0.1 In 0.05

[0062] Preparation of hydrogen storage alloy: according to the atomic ratio of the alloy design composition, the corresponding metal elements Y, Mg, Sc, Ni, Mn and In were weighed as raw materials, the weighed raw materials were put into the crucible of the medium frequency induction furnace, the induction furnace was vacuumed and washed with gas, then argon was filled for smelting, in order to ensure the uniformity of alloy smelting, the cast alloy was obtained after smelting for 3 times. The cast alloy was wrapped with tantalum sheet and sealed in a quartz tube filled with argon, and argon was filled as protective gas in the quartz tube, then the quartz tube was put into a muffle furnace for annealing; the annealing process is as follows: the temperature is raised from room temperature to 650℃ at a rate of 7℃ / min, then the temperature is raised to 850℃ at a rate of 2℃ / min, then the temperature is raised to 980℃ at a rate of 1℃ / min, after 8h of heat preservation, it is naturally cooled to room temperature and taken out, and the hydrogen storage alloy is prepared.

[0063] Hydrogen storage performance test: the alloy prepared in the examples and comparative examples was crushed, 1.5g of alloy powder was taken for pressure-composition-temperature (PCT) test, the test temperature was set to 25℃, and the hydrogen absorption pressure was 9.5MPa. The hydrogen absorption amount, hydrogen release platform pressure and effective hydrogen release amount (hydrogen release amount with hydrogen release platform pressure≥0.1MPa) of the hydrogen storage material were obtained by PCT curve, and the hydrogen absorption and release cycle capacity retention rate test of the alloy was carried out. The pressure-composition-temperature (PCT) curves of examples 1-3 and comparative example 1 are shown in Figure 1

[0064] Alloy phase composition analysis: the alloy powder less than 400 mesh was characterized by X-ray powder diffractometer (XRD), and the Rietveld method was used for analysis to obtain the phase composition and content of the alloy.

[0065] The hydrogen storage performance and alloy phase composition of examples 1-6 and comparative examples 1-12 are shown in table 1.

[0066] Table 1: hydrogen storage performance and alloy phase composition of examples 1-6 and comparative examples 1-12

[0067]

[0068] ​As can be seen from Table 1, by introducing the Sc element with a smaller atomic radius on the A side, the directional contraction of the [A2B4] subunit is realized, the subunit volume difference is reduced, and the lattice parameters of the [AB5] subunit are better matched, thereby reducing the stress accumulation between the subunits and improving the structural stability. In addition, the difference in electronegativity of Sc also helps to optimize the electron distribution and improve the reaction kinetics during the hydrogen absorption / desorption process, so that the alloy has excellent cycle stability and hydrogen storage capacity. Further, by introducing the M element, the alloy structure can be stabilized, which helps to control the diffusion path and activation energy of hydrogen in the lattice, further improving the cycle life and hydrogen desorption platform stability, so that the hydrogen absorption amount of the alloy is up to 1.68 wt%, the effective hydrogen desorption amount is up to 1.59 wt%, and the capacity retention rate is up to 98.5%.

[0069] As can be seen from Comparative Example 1 and Comparative Examples 1-3, the introduction of the Sc element can improve the hydrogen storage performance of the alloy and also improve the stability of the alloy structure. However, when Sc is introduced, the effect of its content on the phase structure of the alloy needs to be considered: when the Sc content is too low, its effect on improving the hydrogen absorption and desorption amount of the alloy is limited. However, when the Sc content is too high, the unit cell will be excessively contracted, which will seriously affect the hydrogen storage capacity.

[0070] As can be seen from Comparative Example 1 and Comparative Examples 4-6, in the Y-Mg-Ni-Mn alloy system, the introduction of any element cannot improve the hydrogen storage capacity and cycle stability of the alloy. When Pr, Gd or Tb element is used to replace Sc element, although the hydrogen absorption amount can reach 1.5 wt%, the hydrogen desorption amount and cycle stability will decrease significantly.

[0071] As can be seen from Comparative Example 1 and Comparative Examples 7-10, in the Y-Mg-Ni-Mn alloy system, when the content of Mg element and Mn element is controlled within a certain range, it can cooperate with the Sc element to improve the hydrogen storage performance and cycle stability of the alloy.

[0072] As can be seen from Comparative Examples 2-6 and Comparative Examples 11-12, although the introduction of the M element can further improve the hydrogen storage performance and cycle stability of the alloy, not any element can be introduced as the M element into the alloy system of the present application. When Pd element or In element is used, the phase composition of the alloy changes from dual-phase (AB3+A2B7) to multi-phase (AB3+A2B7+A5B 19 , AB3+A2B7+AB5), at the same time, the hydrogen absorption amount of the alloy decreases significantly, less than 1.3 wt%, the effective hydrogen desorption amount is less than 1 wt%, and the capacity retention rate is less than 90%.

[0073] The dual-phase superlattice hydrogen storage alloy provided by the application has excellent hydrogen storage capacity and cycle stability, and has a hydrogen absorption capacity of >1.55wt%, an effective hydrogen release capacity of >1.5wt%, and a capacity retention rate of >97%, and has a good application prospect.

[0074] The above examples are only used to illustrate the technical solutions of the application and not to limit the protection scope of the application. Although the application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the application can be modified or replaced equivalently without departing from the essence and scope of the technical solutions of the application.

Claims

1. A two-phase superlattice hydrogen storage alloy, characterized in that, The general chemical formula of the dual-phase superlattice hydrogen storage alloy is: Y 1-a-b Mg a Sc b Ni x Mn y M z M includes at least one of Cr, V, Co, Mo and W, 0.1≤a≤0.15, 0.02≤b≤0.08, 2.8≤x≤3.1, 0<y≤0.15, 0≤z≤0.

1.

2. The dual-phase superlattice hydrogen storage alloy as described in claim 1, characterized in that, 0.11≤a≤0.15, 0.03≤b≤0.06, 2.85≤x≤3.1, 0.08≤y≤0.12, 0≤z≤0.

08.

3. The dual-phase superlattice hydrogen storage alloy as described in claim 1, characterized in that, The hydrogen absorption capacity of the dual-phase superlattice hydrogen storage alloy at room temperature is >1.55wt%, and the effective hydrogen release capacity of the dual-phase superlattice hydrogen storage alloy at room temperature is ≥1.5wt%.

4. The dual-phase superlattice hydrogen storage alloy as described in claim 1, characterized in that, The structural phases of the dual-phase superlattice hydrogen storage alloy are AB3 and A2B7 phases.

5. The dual-phase superlattice hydrogen storage alloy as described in claim 1, characterized in that, The dual-phase superlattice hydrogen storage alloy includes Y 0.84 Mg 0.13 Sc 0.03 Ni 3.1 Mn 0.1 Y 0.83 Mg 0.12 Sc 0.05 Ni 3.05 Mn 0.1 V 0.05 Y 0.79 Mg 0.15 Sc 0.06 Ni 3.1 Mn 0.08 Cr 0. 07 Y 0.8 Mg 0.15 Sc 0.05 Ni 2.85 Mn 0.12 Co 0.08 Y 0.81 Mg 0.15 Sc 0.04 Ni 2.95 Mn 0.11 Mo 0.06 and Y 0.86 Mg 0.11 Sc 0.03 Ni 3.02 Mn 0.08 W 0.05 At least one of them.

6. A method for preparing a two-phase superlattice hydrogen storage alloy as described in any one of claims 1-5, characterized in that, Includes the following steps: According to the general chemical formula Y 1-a-b Mg a Sc b Ni x Mn y M z The raw materials are weighed and mixed according to the specified ratio, and then smelted and annealed to obtain the two-phase superlattice hydrogen storage alloy.

7. The preparation method according to claim 6, characterized in that, The smelting is carried out using the medium-frequency induction smelting method.

8. The preparation method according to claim 6, characterized in that, The annealing process includes: heating from room temperature to 600-700°C at a heating rate of 5-10°C / min, then heating to 800-900°C at a heating rate of 1-3°C / min, then heating to 900-1100°C at a heating rate of 1-3°C / min, holding at that temperature for 6-12 hours, and then cooling.

9. A hydrogen storage device, characterized in that, Including the biphase superlattice hydrogen storage alloy as described in any one of claims 1-5.

10. A hydrogen storage system, characterized in that, Includes the hydrogen storage device as described in claim 9.

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