阅读说明：本技术 一种稀土储氢材料及其制备方法 (Rare earth hydrogen storage material and preparation method thereof ) 是由 苑慧萍 沈浩 蒋利军 王树茂 李志念 郝雷 叶建华 于 2020-05-20 设计创作，主要内容包括：一种稀土储氢材料及其制备方法,涉及一种AB<Sub>2</Sub>型钇-镁-镍基稀土储氢材料。其特征在于其稀土储氢材料为组成通式为Y<Sub>a</Sub>A<Sub>b</Sub>Mg<Sub>c</Sub>Ni<Sub>x</Sub>B<Sub>y</Sub>的钇-镁-镍基储氢材料；该材料具有以AB<Sub>2</Sub>型(Y,A,Mg)(Ni,B)<Sub>2</Sub>相为主相,并同时含有A<Sub>2</Sub>B<Sub>4</Sub>型(Y,A)Mg(Ni,B)<Sub>4</Sub>相和AB<Sub>3</Sub>型(Y,A,Mg)(Ni,B)<Sub>3</Sub>相的混合相结构。其制备方法采用感应熔炼法,并将所得合金铸锭于真空或氩气气氛下进行退火处理。本发明的一种AB<Sub>2</Sub>型钇-镁-镍基稀土储氢材料,A侧通过Mg部分替代,可显著改善合金中AB<Sub>2</Sub>相的结构稳定性,减少合金氢致非晶化和氢致歧化。同时采用较大原子半径的Al、Mn等替代Ni元素,增大合金的晶胞体积,从而增加合金的储氢量,材料具有良好的可逆吸放氢特性,最大储氢量大于1.6wt.％。(A rare earth hydrogen storage material and a preparation method thereof, relating to an AB 2 The type yttrium-magnesium-nickel base rare earth hydrogen storage material. It is characterized in that the rare earth hydrogen storage material is a composition general formula of Y a A b Mg c Ni x B y Yttrium-magnesium of-a nickel-based hydrogen storage material; the material has a chemical formula AB 2 Type (Y, A, Mg) (Ni, B) 2 The phase being the main phase and containing A at the same time 2 B 4 Type (Y, A) Mg (Ni, B) 4 Phase sum AB 3 Type (Y, A, Mg) (Ni, B) 3 Mixed phase structure of phases. The preparation method adopts an induction melting method, and the obtained alloy ingot is annealed in vacuum or argon atmosphere. An AB of the present invention 2 The A side of the yttrium-magnesium-nickel base rare earth hydrogen storage material is partially replaced by Mg, so that AB in the alloy can be obviously improved 2 The structural stability of the phase reduces the hydrogen-induced amorphization and hydrogen-induced disproportionation of the alloy. Meanwhile, Al, Mn and the like with larger atomic radius are adopted to replace Ni elements, and the unit cell volume of the alloy is increased, so that the hydrogen storage capacity of the alloy is increased, the material has good reversible hydrogen absorption and desorption characteristics, and the maximum hydrogen storage capacity is more than 1.6 wt.%.)

1. A rare earth hydrogen storage material is characterized in that the rare earth hydrogen storage material has a general formula of Y_aA_bMg_cNi_xB_yYttrium-magnesium-nickel based hydrogen storage materials; in the general formula of the alloy, A is one or more elements of La, Ce, Pr, Nd, Sm and Gd, B is one or more elements of Al, V, Mn, Fe, Co, Cu and Zn, wherein a is more than or equal to 0.3 and less than 1, B is more than 0 and less than or equal to 0.4, c is more than or equal to 0.05 and less than or equal to 0.4, a + B + c is 1, x is more than or equal to 1.5 and less than or equal to 2.5, y is more than or equal to 0 and less than or equal to 0.5, and x + y is more than or equal to 1.5 and less than or equal to 2.

2. A rare earth hydrogen storage material according to claim 1, characterized in that in the general composition, 0.35. ltoreq. a.ltoreq.0.6, 0. ltoreq. b.ltoreq.0.35, 0.1. ltoreq. c.ltoreq.0.4, 1.9. ltoreq. x.ltoreq.2.1, 0. ltoreq. y.ltoreq.0.3, 1.9. ltoreq. x + y.ltoreq.2.1.

3. A rare earth hydrogen storage material according to claim 1, characterized in that the rare earth hydrogen storage material has AB₂Type (Y, A, Mg) (Ni, B)₂And (4) phase(s).

4. A rare earth hydrogen storage material according to claim 1, characterized in that the rare earth hydrogen storage material has AB₂Type (Y, A, Mg) (Ni, B)₂Phase, A₂B₄Type (Y, A) Mg (Ni, B)₄Phase sum AB₃Type (Y, A, Mg) (Ni, B)₃Mixed phase structure of phases, and in AB₂Type (Y, A, Mg) (Ni, B)₂The phase is the main phase.

5. The method of claim 1, wherein the method comprises the steps of:

(1) preparing alloy raw materials;

(2) under the protection of argon, smelting, refining and casting metal raw materials except Mg;

(3) smelting the obtained cast ingot and metal Mg under a protective atmosphere, and cooling to obtain an alloy cast ingot;

(4) and annealing the obtained alloy ingot in vacuum or argon atmosphere.

6. The method of claim 5, wherein the purity of the alloy raw material is greater than 99.5%.

7. The method for preparing a rare earth hydrogen storage material according to claim 5, wherein the alloy raw material contains Mg which is added by 30-60% of the mass of the raw material and volatile rare earth elements and Mn which are added by 0.5-5% of the mass of the raw material; other alloy raw materials were calculated according to the stoichiometric ratio and weighed.

8. The method for preparing the rare earth hydrogen storage material according to claim 5, wherein the step (2) is to melt under the protection of argon at 1400-1800 ℃, refine for 3-10 min after the alloy is completely melted, cool to obtain an alloy ingot, and repeatedly melt for 1-3 times.

9. The method according to claim 5, wherein the ingot obtained in step (3) is added with Mg metal and then is vacuumized to 1 × 10^-1～5×10^-4And Pa, introducing helium gas or argon/helium gas mixed gas of 0.01-0.1 MPa as protective gas, smelting at 1000-1600 ℃, cooling to obtain an alloy ingot, and repeatedly smelting for 1-3 times.

10. The method for preparing a rare earth hydrogen storage material according to claim 5, wherein the annealing treatment in step (4) is performed on the obtained alloy ingot in vacuum or argon atmosphere, the annealing temperature is 700-950 ℃, and the heat preservation time is 8-24 hours.

Technical Field

A rare earth hydrogen storage material and a preparation method thereof, relating to a hydrogen storage material, in particular to an AB hydrogen storage material₂A yttrium-magnesium-nickel base rare earth hydrogen storage material and a preparation method thereof.

Background

In recent years, in the development and utilization of non-renewable resources such as coal, oil, natural gas, and the like, there have been a series of problems such as energy shortage, resource contention, and environmental pollution caused by excessive use of energy. A new energy system is established, and novel energy which is pollution-free, safe, reliable and sustainable is searched for urgently.

Hydrogen energy is a green and efficient energy carrier, and is increasingly concerned with the advantages of abundant reserves, high combustion heat value, no pollution of products, capability of serving as an energy storage medium, wide application and the like. The storage and transport of hydrogen is a major bottleneck restricting the arrival of hydrogen energy society.

Although the alloy hydrogen storage material has lower capacity than Mg-based and light compound hydrogen storage materials, the alloy hydrogen storage material has good activation performance and can absorb and release hydrogen reversibly at room temperature, and is a hydrogen storage material widely adopted by the existing solid hydrogen storage device. China is a large rare earth resource country, the rare earth alloy hydrogen storage material has resource advantages in China, and the wide application of the rare earth alloy hydrogen storage material is beneficial to the balanced utilization of the rare earth resources in China.

With LaNi₅Is represented by AB₅The type hydrogen storage material is developed earlier, the technology is mature, the theoretical hydrogen storage is only about 1.4 wt.%, and the capacity is lower. Rare earth system AB with superlattice structure_3～4The hydrogen storage alloy has high capacity of about 1.6-1.8 wt.%. Since japan patented early on with such an alloy of a superlattice structure, development and application of the alloy system in China are limited. Therefore, the development of the novel rare earth hydrogen storage material with a new structure has important significance.

AB₂The Laves phase alloy has higher theoretical hydrogen storage capacity, and once draws attention of people. Currently AB₂The type alloy is mainly ZrM₂And TiM₂(M is one or more of Mn, Ni, V, Co and other elements), and the hydrogen storage capacity of the alloy can reach 1.8-2.4 wt.%. But of the rare earth system AB₂The alloy has unstable structure in the hydrogen absorbing and releasing process, so that serious hydrogen-induced non-crystallization and hydrogen-induced disproportionation exist, and the actual hydrogen storage amount is low. Research shows that Y element can obviously inhibit the rare earth AB₂Amorphization of type alloy, at YNi₂For example, the theoretical capacity can reach 2.8 wt.%. The actual hydrogen storage amount is only about 1.7 wt.%, and the alloy structure changes after hydrogen absorption and desorption, so that the capacity is remarkably reduced.

Disclosure of Invention

The invention aims to provide the AB with good structural stability, which can effectively inhibit hydrogen-induced amorphization and hydrogen-induced disproportionation and improve reversible hydrogen storage capacity against the defects of the prior art₂A yttrium-magnesium-nickel base rare earth hydrogen storage material and a preparation method thereof.

In order to achieve the purpose, the invention adopts the following technical scheme.

A rare earth hydrogen storage material is characterized in that the rare earth hydrogen storage material has a general formula of Y_aA_bMg_cNi_xB_yYttrium-magnesium-nickel based hydrogen storage materials; in the general formula of the alloy, A is one or more elements of La, Ce, Pr, Nd, Sm and Gd, B is one or more elements of Al, V, Mn, Fe, Co, Cu and Zn, wherein a is more than or equal to 0.3 and less than 1, B is more than 0 and less than or equal to 0.4, c is more than or equal to 0.05 and less than or equal to 0.4, a + B + c is 1,1.5≤x≤2.5，0≤y≤0.5，1.5≤x+y≤2.5。

the rare earth hydrogen storage material is characterized in that in the general formula of the composition, a is more than or equal to 0.35 and less than or equal to 0.6, b is more than 0 and less than or equal to 0.35, c is more than or equal to 0.1 and less than or equal to 0.4, x is more than or equal to 1.9 and less than or equal to 2.1, y is more than or equal to 0 and less than or equal to 0.3, and x + y is more than or equal to 1.9 and less.

The rare earth hydrogen storage material is characterized in that the rare earth hydrogen storage material has AB₂The yttrium-magnesium-nickel base rare earth hydrogen storage material.

The rare earth hydrogen storage material is characterized by comprising AB₂Type (Y, A, Mg) (Ni, B)₂Phase, A₂B₄Type (Y, A) Mg (Ni, B)₄Phase sum AB₃Type (Y, A, Mg) (Ni, B)₃Mixed phase structure of phases, and in AB₂Type (Y, A, Mg) (Ni, B)₂The phase is the main phase.

The invention discloses a preparation method of a rare earth hydrogen storage material, which is characterized by comprising the following preparation steps:

(1) preparing alloy raw materials;

(2) under the protection of argon, smelting, refining and casting metal raw materials except Mg;

(3) smelting the obtained cast ingot and metal Mg under a protective atmosphere, and cooling to obtain an alloy cast ingot;

(4) and annealing the obtained alloy ingot in vacuum or argon atmosphere.

The preparation method of the rare earth hydrogen storage material is characterized in that the purity of the alloy raw material is more than 99.5%.

The preparation method of the rare earth hydrogen storage material is characterized in that calculated according to the stoichiometric ratio in the alloy raw materials, the metal Mg needs to increase the burning loss amount by 30-60% of the mass of the ingredients, and the volatile rare earth element and the Mn element increase the burning loss amount by 0.5-5% of the mass of the ingredients; other alloy raw materials were calculated according to the stoichiometric ratio and weighed.

The preparation method of the rare earth hydrogen storage material is characterized in that the step (2) is to melt under the protection of argon at 1400-1800 ℃, refine for 3-10 min after the alloy is completely melted, obtain an alloy ingot after cooling, and repeatedly melt for 1-3 times.

The preparation method of the rare earth hydrogen storage material is characterized in that in the step (3), after the obtained cast ingot is added with metal Mg, the cast ingot is vacuumized to 1 × 10^-1～5×10^-4And Pa, introducing helium gas or argon/helium gas mixed gas of 0.01-0.1 MPa as protective gas, smelting at 1000-1600 ℃, cooling to obtain an alloy ingot, and repeatedly smelting for 1-3 times.

The preparation method of the rare earth hydrogen storage material is characterized in that the step (4) is to anneal the obtained alloy ingot in vacuum or argon atmosphere, the annealing temperature is 700-950 ℃, and the heat preservation time is 8-24 hours.

An AB of the present invention₂The A side of the yttrium-magnesium-nickel base rare earth hydrogen storage material is partially replaced by Mg, so that AB in the alloy can be obviously improved₂The structural stability of the phase reduces the hydrogen-induced amorphization and hydrogen-induced disproportionation of the alloy. Meanwhile, Al, Mn and the like with larger atomic radius are adopted to replace Ni elements, and the unit cell volume of the alloy is increased, so that the hydrogen storage capacity of the alloy is increased. The material of the invention has good reversible hydrogen absorption and desorption characteristics, and the maximum hydrogen storage amount is more than 1.6 wt.%.

Drawings

FIG. 1 is a graph of the reversible hydrogen absorption kinetics of the hydrogen storage alloys of examples 1, 2, 8 and comparative examples 1, 2, 3.

Detailed Description

The following examples are provided to further illustrate the present invention, but the scope of the present invention is not limited to the following examples.

A rare earth hydrogen storage material has a general formula of Y_aA_bMg_cNi_xB_yYttrium-magnesium-nickel based hydrogen storage materials; in the general formula of the alloy, A is one or more elements of La, Ce, Pr, Nd, Sm and Gd, B is one or more elements of Al, V, Mn, Fe, Co, Cu and Zn, wherein a is more than or equal to 0.3 and less than 1, B is more than 0 and less than or equal to 0.4, c is more than or equal to 0.05 and less than or equal to 0.4, a + B + c is 1, x is more than or equal to 1.5 and less than or equal to 2.5, y is more than or equal to 0 and less than or equal to 0.5, and x + y is more than or equal to 1.5 and less than or equal to 2. Preferably 0.35≤a≤0.6，0＜b≤0.35，0.1≤c≤0.4，1.9≤x≤2.1，0≤y≤0.3，1.9≤x+y≤2.1。

The rare earth hydrogen storage material of the invention has AB₂Type (Y, A, Mg) (Ni, B)₂Phase, A₂B₄Type (Y, A) Mg (Ni, B)₄Phase sum AB₃Type (Y, A, Mg) (Ni, B)₃Mixed phase structure of phases; mixed phase structure with AB₂Type (Y, A, Mg) (Ni, B)₂The phase is the main phase.

The preparation method of the rare earth hydrogen storage material comprises the following steps:

(1) calculating and weighing alloy raw materials with the purity of not less than 99.5% according to a stoichiometric ratio, wherein the burning loss of metal Mg needs to be increased by 30-60% of the mass of the ingredients, and the burning loss of volatile elements such as rare earth elements and Mn needs to be increased by 0.5-5% of the mass of the ingredients;

(2) smelting metal raw materials except Mg under the protection of argon at 1400-1800 ℃, refining for 3-10 min after the alloy is completely melted, cooling to obtain an alloy ingot, and repeatedly smelting for 1-3 times;

(3) adding metal Mg, and vacuumizing to 1 × 10^-1～5×10^-4And Pa, introducing helium gas or argon/helium gas mixed gas of 0.01-0.1 MPa as protective gas, smelting at 1000-1600 ℃, cooling to obtain an alloy ingot, and repeatedly smelting for 1-3 times.

(4) And annealing the obtained alloy ingot in vacuum or argon atmosphere at 700-950 ℃ for 8-24 hours.