JP4762579B2 - Hydrogen storage material, production method thereof, and hydrogen storage method - Google Patents

Description

  The present invention relates to a hydrogen storage material that generates hydrogen used as a fuel for fuel cells and the like, a method for producing the same, and a method for storing hydrogen after releasing hydrogen from the hydrogen storage material.

NO _X and development of fuel cells have been actively as a clean energy source that does not emit greenhouse gases such as toxic substances and CO ₂ in the SO _X or the like, and is already practiced in several areas. As an important technology that supports this fuel cell technology, there is a technology for storing hydrogen as fuel for the fuel cell. Known storage forms of hydrogen include compression storage using a high-pressure cylinder, cooling storage using liquid hydrogenation, storage using a hydrogen storage material, and the like.

  Among these hydrogen storage forms, storage with a hydrogen storage material is advantageous in terms of distributed storage and transportation. Hydrogen storage materials include materials with a high hydrogen storage rate, that is, materials with a high hydrogen storage amount per unit weight or volume of the hydrogen storage material, materials that absorb and release hydrogen at a low temperature, and good durability. A material having is desired.

Known hydrogen storage materials include metal materials centered on rare earth, titanium, vanadium, magnesium, etc., lightweight inorganic compounds such as metal alanade (for example, NaAlH ₄ and LiAlH ₄ ), carbon, and the like. In addition, for example, a hydrogen storage method using lithium nitride represented by the following formula (1) has been reported (for example, see Non-Patent Documents 1 and 2).
_{Li 3 N + 2H 2 = Li} 2 NH + LiH + H 2 = LiNH 2 + 2LiH ... (1)

Here, absorption of hydrogen by Li ₃ N started from about 100 ° C., and 9.3 mass% hydrogen absorption was confirmed at 255 ° C. for 30 minutes. In addition, it has been reported that the absorption characteristics of absorbed hydrogen pass through two steps: 6.3% by mass at less than 200 ° C. and 3.0% by mass at 320 ° C. or higher by slowly heating. . That is, the reaction of the following formula (2) corresponding to the right side portion of the above formula (1) starts to proceed at a little less than 200 ° C., and the reaction of the following formula (3) corresponding to the left side portion of the above formula (1) is about 320 It has been shown to begin to progress at ° C.
LiNH ₂ + 2LiH → Li ₂ NH + LiH + H ₂ ↑ (2)
Li ₂ NH + LiH → Li ₃ N + H ₂ ↑ (3)

However, the lithium nitride represented by the above formula (1) has a problem that the hydrogen release start temperature and the hydrogen release peak temperature are high.
Ruff, O., and Goerges, H., Berichte der Deutschen Chemischen Gesellschaft zu Berlin, Vol. 44, 502-6 (1911) Ping Chen et al., Interaction of hydrogen with metalnitrides andimides, NATURE Vol.420, 21 NOVEMBER 2002, p302〜304

  The present invention has been made in view of such circumstances, and an object thereof is to provide a hydrogen storage material having a low hydrogen release start temperature and a low hydrogen release peak temperature. Another object of the present invention is to provide a method for producing such a hydrogen storage material. A further object of the present invention is to provide a hydrogen storage method for increasing the hydrogen storage rate after releasing hydrogen from such a hydrogen storage material.

According to the first aspect of the present invention , lithium hydride (LiH) and at least one of magnesium amide (Mg (NH ₂ ) ₂ ) and calcium amide (Ca (NH ₂ ) ₂ ) as a metal amide compound , hydrogen storage material characterized by have a mixture of and reactants, is provided.

In this hydrogen storage material, wherein the mixture and the reactants are not preferable that further includes a catalyst comprising a Ti compound which enhances hydrogen release capacity. Also, the supported amount of the catalyst, the lithium hydride and (LiH), and at least one magnesium amide as metal amide compound (Mg _{(NH 2) 2)} and calcium amide (Ca _{(NH 2) 2)} It is preferable to set it as 0.1 mass% or more and 20 mass% or less of a mixture and reaction material of these.

Further, in the hydrogen storage material of the present invention may further comprise a lithium amide (LiNH ₂₎ as the metal amide compound. Furthermore, in the hydrogen storage material of the present invention, it is preferable that the mixture and the reactant are nanostructured and organized by mechanical milling treatment.

According to a second aspect of the present invention , lithium hydride (LiH) and at least one of magnesium amide (Mg (NH ₂ ) ₂ ) and calcium amide (Ca (NH ₂ ) ₂ ) as a metal amide compound , Is produced in an inert gas atmosphere, a hydrogen gas atmosphere, or a mixed gas atmosphere of an inert gas and a hydrogen gas, and a method for producing a hydrogen storage material is provided.

  According to a third aspect of the present invention, lithium hydride (LiH) and magnesium amide (Mg (NH ₂ ) ₂ ) And calcium amide (Ca (NH ₂ ) ₂ And a mixture of at least one of the above in an inert gas atmosphere, a hydrogen gas atmosphere, or a mixed gas atmosphere of an inert gas and hydrogen gas,
  In the mixing step, a step further comprises adding a catalyst composed of a Ti compound that enhances the ability to absorb and desorb hydrogen to carry the catalyst composed of the Ti compound on the object to be treated, or an object to be treated and hydrogen absorption / desorption obtained after the mixing step. At least one of the lithium hydride (LiH) and the metal amide compound before the mixing step, or the step of loading the catalyst consisting of the Ti compound on the object to be treated One of the steps of supporting a catalyst made of a Ti compound that enhances the ability to absorb and release hydrogen on one side;
  A method for producing a hydrogen storage material is provided.

  In such a method for producing a hydrogen storage material, it is preferable that the atmospheric pressure when the lithium hydride (LiH) and the metal amide compound are mixed to be atmospheric pressure or higher. Further, as a metal amide compound, lithium amide (LiNH ₂ ) May be mixed. Furthermore, when the lithium hydride (LiH) and the metal amide compound are mixed, it is preferable that the mixture and the reactant are nanostructured and organized by mechanical milling.

According to a fourth aspect of the present invention , there is provided a hydrogen storage material produced by the production method of the second aspect and the third aspect.

According to the fifth aspect of the present invention, hydrogen is occluded in a pressurized hydrogen gas atmosphere with respect to a material after releasing hydrogen from the hydrogen storage material produced by the above-described method for producing a hydrogen storage material. A hydrogen storage method is provided.
In this hydrogen storage method, the pressure of the pressurized hydrogen gas atmosphere is preferably 4 MPa or more. Further, the reaction temperature for storing hydrogen is preferably 80 ° C. or higher.

  According to the present invention, it is possible to obtain a hydrogen storage material in which the hydrogen generation temperature and the hydrogen release peak temperature are greatly reduced as compared with the prior art. Moreover, the material after releasing hydrogen from the hydrogen storage material can be regenerated with a high hydrogen storage rate. That is, a decrease in the hydrogen release rate can be prevented.

Embodiments of the present invention will be described below.
The hydrogen storage material of the present invention includes a mixture and a reaction product of a metal hydride and a metal amide compound, and these metal species are at least two or more. Specifically, (1) when the metal constituting the metal hydride is different from the metal constituting the metal amide compound, (2) when containing a plurality of types of metal hydrides having different metal components, (3 In the case of including a plurality of types of metal amide compounds having different metal components,

A suitable example is a metal hydride (LiH) having a property that the decomposition temperature is low in the metal hydride, considering only lowering of the hydrogen release temperature, and the metal amide compound is at least Including magnesium amide (Mg (NH ₂ ) ₂ ), calcium amide (Ca (NH ₂ ) ₂ ) alone or a mixture thereof, which decomposes at a lower temperature than lithium hydride (LiH) to produce ammonia (NH ₃ ). The combination is preferable.

As can be seen by comparing Example 1 and Example 2 described later, when the metal amide compound is used alone (single component), the hydrogen storage rate increases as the atomic weight of the metal element constituting the metal amide compound increases. descend. Therefore, it is practical to use a combination of the lightest lithium amide (LiNH ₂ ) and magnesium amide (Mg (NH ₂ ) ₂ ) or calcium amide (Ca (NH ₂ ) ₂ ) for lowering the temperature. preferable.

In the case of a hydrogen storage material using lithium hydride (LiH), lithium amide (LiNH ₂ ) and magnesium amide (Mg (NH ₂ ) ₂ ), when blending so that each substance is equivalent, What is necessary is just to use combining each substance like the following Formula (4). In the formula (4), it is preferable that a = b + 2c. Further, it is possible to use lithium imide (eg, Li _2.2 NH) deviating from the equivalent, but in that case, the hydrogen storage amount per unit mass of the used raw material is reduced.
aLiH + bLiNH ₂ + cMg (NH ₂ ) ₂ →
aH ₂ + (b + c) Li ₂ NH + cMgNH (4)

In the case of a hydrogen storage material using lithium hydride (LiH) and magnesium amide (Mg (NH ₂ ) ₂ ), it is preferable to combine the substances as in the following formula (5) or the following formula (6). . Thereby, a hydrogen storage rate can be raised.
8LiH + 3Mg (NH ₂ ) ₂ → 8H ₂ + 4Li ₂ NH + Mg ₃ N ₂ (5)
12LiH + 3Mg (NH ₂ ) ₂ → 12H ₂ + 4Li ₃ N + Mg ₃ N ₂ (6)

  Such a mixture and reaction product of a metal hydride and a metal amide compound are preferably nanostructured and organized by mechanical milling. This mechanical milling process can be performed by using a planetary ball mill or the like in the case of small-scale production, and in the case of mass production, the inventors previously disclosed various types disclosed in Japanese Patent Application No. 2004-036967. The mixing / pulverization method can be performed using, for example, a roller mill, an inner / outer cylinder rotary mill, an attritor, an inner piece mill, an airflow mill mill, and the like.

  In order to obtain a mixture of metal hydride and metal amide compound and a reaction product, the mixing / pulverization treatment of metal hydride and metal amide compound is performed under an inert gas (eg, argon gas, nitrogen gas) atmosphere or hydrogen gas. It is performed in an atmosphere or in a mixed gas atmosphere of an inert gas and hydrogen gas. At this time, the atmospheric pressure (gas pressure) is preferably set to atmospheric pressure or higher. This increases the amount of hydrogen released from the mixture and the reactants after the mixing / grinding process, for no clear reason.

  It is preferable that the mixture and reactant of the metal hydride and the metal amide compound contain a catalyst that enhances the ability to absorb and release hydrogen. Suitable catalysts are B, C, Mn, Fe, Co, Ni, Pt, Pd, Rh, Na, Mg, K, Ir, Nd, La, Ca, V, Ti, Cr, Cu, Zn, Al, Si. , Ru, Mo, Nb, Ta, Zr, Hf, and Ag, or a hydrogen storage alloy.

  The amount of the catalyst supported is preferably 0.1% by mass or more and 20% by mass or less of the mixture of the metal hydride and metal amide and the reaction product. When the amount of the catalyst supported is less than 0.1% by mass, the effect of promoting the hydrogen generation reaction cannot be obtained. When the amount exceeds 20% by mass, the reaction between the reactants such as metal hydride is inhibited. The hydrogen storage rate per mass will decrease.

  One of the following three methods is used as a method for supporting a catalyst substance having hydrogen absorption / release capability on a mixture and a reaction product of a metal hydride and a metal amide compound. That is, (a) by adding a catalyst substance when mixing and pulverizing a metal hydride and a metal amide compound, the product to be treated (that is, a metal hydride, a metal amide compound, a mixture thereof, a reaction product thereof) A method of supporting, (b) a method of supporting a catalyst material on a material to be processed by mixing the material to be processed obtained by mixing and pulverizing a metal hydride and a metal amide compound, and (c) a metal. Before mixing and pulverizing the hydride and the metal amide compound, any of a method in which at least one of the metal hydride and the metal amide compound is loaded with a catalyst substance having a hydrogen absorption / release capability by a mixed pulverization process or the like is used.

  As a method for storing hydrogen in the material after releasing hydrogen from the hydrogen storage material thus produced, a method of exposing the material to a pressurized hydrogen gas atmosphere is used, and the pressurized hydrogen gas atmosphere at that time is used. The pressure is preferably 4 MPa or more. When the pressure of the pressurized hydrogen gas atmosphere is less than 4 MPa, hydrogenation is difficult to proceed, and unreacted materials may remain and the hydrogen storage rate may decrease. On the other hand, the pressure in the pressurized hydrogen gas atmosphere is preferably 15 MPa or less. This is because a large pressure resistance is required for the container used for storing hydrogen, which is not industrially preferable.

  The temperature during the hydrogen storage treatment is preferably 80 ° C. or higher. This is because when the hydrogen storage temperature is less than 80 ° C., hydrogenation is difficult to proceed, and unreacted materials may remain and the hydrogen storage rate may decrease. The hydrogen storage temperature is preferably 300 ° C. or lower. In the hydrogen occlusion process at a temperature exceeding 300 ° C., the amount of heat required for the occlusion process increases, which is not industrially preferable.

  Next, examples and comparative examples of the present invention will be described.

(Preparation of various metal amides)
For example, magnesium amide (Mg (NH ₂ ) ₂ ) is charged with 1 g of magnesium hydride (MgH ₂ ) in a high-chromium steel mill container (internal volume: 250 ml) in a high-purity argon glove box. The inside of the mill container is evacuated, and then, a predetermined amount is placed in the mill container so that the molar ratio of the following formula (7) is exceeded and the inside of the mill container is 0.4 MPa or less (absolute pressure). After the introduction of ammonia gas, the mill container was sealed, and then this was prepared by milling for a predetermined time at a rotation speed of 250 rpm in an air atmosphere at room temperature. Formation of various metal amides was confirmed by measuring the amount of hydrogen in the reaction gas and XRD from the mill vessel after milling. Lithium amide and calcium amide were also prepared in the same manner. The raw materials used for the preparation of each metal amide are as shown in Table 1.
MgH ₂ + 2NH ₃ (g) → Mg (NH ₂ ) ₂ + 2H ₂ (g) (7)

(Examples 1-8 )
Table 2 shows the composition of the starting materials of Examples 1 to 8 and Comparative Examples 1 and 2 described below. A predetermined raw material selected from lithium hydride (LiH), magnesium hydride (MgH ₂ ), lithium amide (LiNH ₂ ), magnesium amide (Mg (NH ₂ ) ₂ ), calcium amide (Ca (NH ₂ ) ₂ ) As shown in Table 2, for Examples 1 to 6 , titanium trichloride (TiCl ₃ ) is the total moles of the starting metal components so as to have a predetermined composition containing two or more kinds of metal elements as shown in Table 2. Each was measured in a high-purity argon glove box so as to be 1.0 mol% of the amount, and put in a mill vessel with a valve made of high chromium steel. Subsequently, after the inside of the mill container was evacuated, 1 MPa of high-purity hydrogen gas was introduced, and a planetary ball mill apparatus (manufactured by Fritsch, P-5) was used at room temperature in an air atmosphere at a rotation speed of 250 rpm. Milled for 2 hours. After milling, the mill container was evacuated and filled with argon gas, and then taken out in a high purity argon glove box.

(Comparative Examples 1 and 2)
In Comparative Example 1, lithium hydride (LiH) and lithium amide (LiNH ₂ ) are used, and in Comparative Example 2, magnesium hydride (MgH ₂ ) is used so that the metal hydride and the metal amide compound contain one kind of metal. Magnesium amide (Mg (NH ₂ ) ₂ ) so as to have a predetermined composition shown in Table 2, respectively, and titanium trichloride (TiCl ₃ ) is 1.0 mol% of the total molar amount of the starting metal components. In a high purity argon glove box, it was weighed and put into a high chrome steel valve-equipped mill vessel. Subsequently, after the inside of the mill container was evacuated, 1 MPa of high-purity hydrogen gas was introduced, and milling was performed using a planetary ball mill apparatus at room temperature in an air atmosphere at a rotational speed of 250 rpm for 2 hours. After milling, the mill container was evacuated and filled with argon gas, and then taken out in a high purity argon glove box.

(Sample evaluation)
Using the TG-MASS apparatus (thermogravimetric / mass spectrometer) installed in the high purity argon glove box, the temperature of the sample prepared as described above was increased at a rate of 5 ° C./min. The desorbed gas from each sample was collected and analyzed.

(Measurement of hydrogen storage characteristics)
The sample according to Example 7 was filled in a SUS container and held in a vacuum atmosphere at 200 ° C. for 12 hours to perform hydrogen release treatment. The sample after the hydrogen releasing treatment was taken out in a high purity argon glove box, and the same amount was weighed and filled in two pressure-resistant containers. Subsequently, after each vacuum vessel was evacuated, high-purity hydrogen gas was introduced into one of the pressure vessels so that the internal pressure became 10 MPa, and a hydrogen occlusion treatment was performed by holding at 200 ° C. for 12 hours ( Hereinafter, the hydrogen storage material thus obtained is referred to as “Example 9 ”). In addition, a high-purity hydrogen gas was introduced into the other pressure vessel so that the internal pressure was 3 MPa, and the hydrogen storage treatment was performed by holding at 200 ° C. for 12 hours (hereinafter, the hydrogen storage material obtained in this way was referred to as “ Example 10 ”). The samples of Examples 9 and 10 thus produced were heated using a TG-MASS apparatus installed in a high-purity argon glove box at a heating rate of 5 ° C./min, and the samples were removed from the samples at that time. The separated gas was collected and analyzed.

(PCT measurement)
The sample according to Example 7 was filled in a SUS container and held in a vacuum atmosphere at 200 ° C. for 12 hours to perform hydrogen release treatment. The sample after the hydrogen releasing treatment was taken out in a high purity argon glove box, and the same amount was weighed and filled in two pressure-resistant containers. Subsequently, after evacuating each pressure vessel, one of the pressure vessels is maintained at 200 ° C., and high-purity hydrogen gas is appropriately introduced so that the internal pressure becomes 1 MPa to 9 MPa, and PCT at a predetermined pressure is obtained. The measurement was performed (the sample finally obtained in this way is referred to as “Example 11 ”). Also, the other pressure vessel was held at 150 ° C., and high-purity hydrogen gas was introduced as appropriate so that the internal pressure would be 1 MPa to 9 MPa, and PCT measurement was performed at a predetermined pressure (thus finally obtained). The sample was referred to as “Example 12 ”). In each pressure vessel, the equilibrium waiting time under each pressure was 1 hour.

(Measurement of hydrogen storage start temperature)
The sample according to Example 7 was filled in a SUS container and held in a vacuum atmosphere at 200 ° C. for 12 hours to perform hydrogen release treatment. The sample after the hydrogen releasing treatment was taken out in a high purity argon glove box, and the same amount was weighed and filled in two pressure-resistant containers. Subsequently, after evacuating each pressure vessel, one pressure vessel was held at 10 MPa, and the hydrogen storage amount from room temperature to 200 ° C. was measured (the sample thus obtained was referred to as “Example 13 ”). And). The other pressure vessel was held at 3 MPa, and the hydrogen occlusion amount from room temperature to 200 ° C. was measured (the sample finally obtained in this way is referred to as “Example 14 ”).

(result)
FIG. 1 shows an emission spectrum of desorbed hydrogen gas accompanying a temperature rise by the TG-MASS apparatus, that is, an explanatory diagram showing the relationship between temperature and hydrogen emission intensity. The characteristic line a in FIG. 1 is Example 1, the characteristic line b is Example 7 , the characteristic line c is Example 8 , the characteristic line d is Comparative Example 1, the characteristic line e is Comparative Example 2, Each is shown. Table 2 also shows the theoretical hydrogen storage rate (mass%) of each sample and the peak temperature (° C.) of the hydrogen gas release spectrum curve (hereinafter referred to as “hydrogen release peak temperature”).

From FIG. 1, the hydrogen release peak temperature of Example 1 is 209 ° C., and the hydrogen release peak temperature of Example 8 is 189 ° C., which is compared with 239 ° C. in Comparative Example 1 and 317 ° C. in Comparative Example 2. Thus, it was confirmed that the hydrogen release peak temperature was lowered. Further, as shown in Table 2, it was confirmed that in Examples 2 to 7 , the hydrogen release peak temperature was lower than that in Comparative Example 1.

FIG. 2 shows a TG curve by the TG-MASS apparatus, that is, a graph showing the relationship between the temperature and the thermal weight reduction rate (wt%). In FIG. 2, the TG curve f indicates Example 7 , the TG curve g indicates Example 9 , and the TG curve h indicates Example 10 . As shown in FIG. 2, the weight reduction rate of Example 7 was 7.2 wt%, which was confirmed to be substantially equal to the theoretical hydrogen storage rate. Further, in Example 9 obtained by performing hydrogen storage treatment in a 10 MPa hydrogen gas atmosphere after subjecting the sample according to Example 7 to hydrogen release treatment, the weight reduction rate was 6.9 wt%, which is almost equal to the theoretical hydrogen storage rate. It was confirmed that they were equal. On the other hand, in the case of Example 10 where the hydrogen gas pressure in the hydrogen storage treatment was 3 MPa, the weight reduction rate was 4.8 wt%.

FIG. 3 is a graph showing the relationship between the hydrogen storage amount and the hydrogen gas pressure when the hydrogen gas pressure is changed at a predetermined temperature after the sample according to Example 7 is subjected to hydrogen release treatment. From FIG. 3, the hydrogen storage amount of Example 11 in which the temperature of the hydrogen storage treatment is 200 ° C. is about 6.5 mass%, and it was confirmed that the hydrogen storage near the theoretical hydrogen amount was stored. Further, the hydrogen storage amount of Example 12 where the temperature of the hydrogen storage treatment was 150 ° C. was about 4.1 mass%.

FIG. 4 is a graph showing the relationship between the occlusion temperature and the hydrogen occlusion amount when the hydrogen gas pressure was changed from room temperature to 200 ° C. after the sample according to Example 7 was subjected to hydrogen desorption treatment. From FIG. 4, it was confirmed that the hydrogen storage start temperature of Example 13 in which the hydrogen storage pressure was 10 MPa was 80 ° C. On the other hand, it was confirmed that the hydrogen storage start temperature of Example 14 in which the hydrogen storage pressure was 3 MPa was 100 ° C.

  The hydrogen storage material, the production method thereof, and the hydrogen storage method of the present invention are suitable for a fuel cell that generates power using hydrogen and oxygen as fuels and the operation thereof.

The diagram which shows the relationship between temperature rising temperature and hydrogen discharge | release intensity | strength. The graph which shows the relationship between temperature rising temperature and a weight decreasing rate. The graph which shows the relationship between hydrogen storage amount and storage pressure. The graph which shows the relationship between hydrogen storage temperature and hydrogen storage amount.

Claims (14)

Features and lithium hydride (LiH), to have a mixture and a reaction product of at least one magnesium amide as metal amide compound (Mg _{(NH 2) 2)} and calcium amide (Ca _{(NH 2) 2)} And hydrogen storage material. The hydrogen storage material according to claim 1, further comprising a catalyst made of a Ti compound that enhances the ability to absorb and release hydrogen. The amount of the catalyst supported is a mixture of the lithium hydride (LiH) and at least one of magnesium amide (Mg (NH ₂ ) ₂ ) and calcium amide (Ca (NH ₂ ) ₂ ) as a metal amide compound , and The hydrogen storage material according to claim 2, wherein the content is 0.1% by mass or more and 20% by mass or less of the reactant.   As a metal amide compound, lithium amide (LiNH ₂ The hydrogen storage material according to any one of claims 1 to 3, wherein The hydrogen storage material according to any one of claims 1 to 4, wherein the mixture and the reactant are nanostructured and organized by a mechanical milling process.   Lithium hydride (LiH) and magnesium amide (Mg (NH ₂ ) ₂ ) And calcium amide (Ca (NH ₂ ) ₂ And at least one of them in an inert gas atmosphere, a hydrogen gas atmosphere, or a mixed gas atmosphere of an inert gas and hydrogen gas. Lithium hydride (LiH) and at least one of magnesium amide (Mg (NH ₂ ) ₂ ) and calcium amide (Ca (NH ₂ ) ₂ ) as a metal amide compound are used in an inert gas atmosphere or a hydrogen gas atmosphere Mixing under or in a mixed gas atmosphere of an inert gas and hydrogen gas,
In the mixing step, a step further comprises adding a catalyst composed of a Ti compound that enhances the ability to absorb and desorb hydrogen to carry the catalyst composed of the Ti compound on the object to be treated, or an object to be treated and hydrogen absorption / desorption obtained after the mixing step. at least step of supporting a catalyst comprising the Ti compound to the object to be processed by admixing a catalyst comprising a Ti compound which enhances performance, or the mixing step wherein lithium hydride before and (LiH) of the metal amide compound One of the steps of supporting a catalyst made of a Ti compound that enhances the ability to absorb and release hydrogen on one side;
A method for producing a hydrogen storage material, comprising: The method for producing a hydrogen storage material according to claim 6 or 7 , wherein an atmospheric pressure when the lithium hydride (LiH) and the metal amide compound are mixed is set to atmospheric pressure or higher.   As a metal amide compound, lithium amide (LiNH ₂ The method for producing a hydrogen storage material according to any one of claims 6 to 8, wherein the hydrogen storage material is mixed. 10. The structure according to claim 6, wherein when the lithium hydride (LiH) and the metal amide compound are mixed, the mixture and the reactant are nanostructured and organized by a mechanical milling process. The manufacturing method of hydrogen storage material as described in any one of . A hydrogen storage material manufactured by the method for manufacturing a hydrogen storage material according to any one of claims 6 to 10 . A hydrogen storage material produced by the method for producing a hydrogen storage material according to any one of claims 6 to 10 is made to occlude hydrogen in a pressurized hydrogen gas atmosphere with respect to the material after releasing hydrogen from the hydrogen storage material. Hydrogen storage method.   The hydrogen storage method according to claim 12, wherein the pressure of the pressurized hydrogen gas atmosphere is 4 MPa or more.   The hydrogen storage method according to claim 12 or 13, wherein a reaction temperature for storing the hydrogen is 80 ° C or higher.

Images