KR102443563B1 - Complex structure hydrogen storage alloy with the excellent activate property - Google Patents

Abstract

One embodiment of the present invention provides a hydrogen storage alloy including an AB-based alloy matrix and an ABm alloy phase having a Laves structure precipitated on the AB-based alloy matrix, wherein m satisfies the condition 1.2 <= m <= 2.5. According to an embodiment of the present invention, components are controlled by adding Cr or Mn to form a Laves structure partially in the AB-based alloy matrix, which enables activation at room temperature, thereby providing a hydrogen storage alloy capable of absorbing hydrogen without performing a conventional high-temperature activation process.

Description

Complex structure hydrogen storage alloy with the excellent activate property

The present invention relates to a hydrogen storage alloy, and more particularly, to a composite structure hydrogen storage alloy having excellent activation properties.

Recently, as the necessity of using hydrogen to solve environmental problems and to replace fossil fuels has emerged, research on hydrogen fuel is being actively conducted. However, since hydrogen exists as a gas at room temperature and atmospheric pressure, the energy density per volume is low, transportation and storage are inconvenient, and safety is poor.

As a storage method of such hydrogen, a method of compressing and storing hydrogen gas, a method of liquefying the storage method, or a method using an alloy for storage of hydrogen are known.

However, the method of compressing hydrogen gas consumes a lot of energy because it has to be compressed at a high pressure, and there is a risk of explosion, especially in a city center.

In addition, since liquid hydrogen must be cooled to a cryogenic temperature of -253 degrees Celsius, energy consumption is extreme, and a significant amount of liquid hydrogen is vaporized and evaporated when stored at room temperature, so it is not suitable for long-term use, especially in urban areas.

Therefore, studies on hydrogen storage alloys that consume less energy, are safe, and can be stored for a long time are active.

Since the hydrogen storage alloy is a metal component, the weight storage density is low, but the volume storage density is quite excellent, and the hydrogen storage amount thereof reaches up to 110 kg/m ³ . Therefore, it is particularly suitable for long-term use in fuel systems that do not require movement, such as at home or in the city.

Hydrogen storage alloy is an alloy that forms metal hydride by accepting atomic hydrogen in the crystal lattice by reacting reversibly with hydrogen. It is used to store and release hydrogen by using the absorption and release characteristics of hydrogen.

The hydrogen storage alloy can be expressed as A _x B _y , and depending on the stoichiometric ratio of A and B components, AB ₅ , AB ₂ , AB ₃ , A ₂ B ₇ , A ₆ B ₂₃ , AB, A ₂ B approximately It can be divided into 7 types. Element A forms a stable hydride because of its high chemical affinity with hydrogen, whereas B lowers the stability of the hydride to enable a reversible reaction.

Therefore, it was necessary to develop a hydrogen storage alloy that is easy to absorb and release hydrogen while maintaining good reversibility even after repeated use.

In particular, AB-based hydrogen storage alloys are known to have high hydrogen absorption capacity and high durability in reversible reactions. there were difficulties in

Republic of Korea Patent Publication No. 10-0871903

An object of the present invention is to provide a hydrogen storage alloy having excellent activation properties capable of absorbing hydrogen without going through a high-temperature activation process.

The technical problems to be achieved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by those of ordinary skill in the art to which the present invention belongs from the description below. There will be.

In order to achieve the above technical problem, an embodiment of the present invention provides a hydrogen storage alloy.

In an embodiment of the present invention, the hydrogen storage alloy is an AB-based alloy matrix; and an AB _m alloy phase having a Laves structure deposited on the AB-based alloy matrix, wherein A and B are metals, and m may satisfy the condition 1.2≤m≤2.5.

In an embodiment of the present invention, in the AB-based alloy matrix, A may include Ti, Zr or V, and B may include Fe.

In an embodiment of the present invention, in the AB _m -based alloy phase, A may include Ti, Zr, or V, and B may include at least one selected from Cr and Mn.

In an embodiment of the present invention, B may further include Fe.

In an embodiment of the present invention, B may further include Co, Ni, Cu or Al.

In order to achieve the above technical object, another embodiment of the present invention provides a hydrogen storage alloy.

In an embodiment of the present invention, the hydrogen storage alloy has a chemical formula whose entire composition is represented by TiFe _1-x M _x , wherein M includes at least one selected from Cr and Mn, wherein x is greater than 0 0.3 may be below.

In an embodiment of the present invention, as the content of M increases within the x range, the activation characteristic may increase.

In order to achieve the above technical object, another embodiment of the present invention provides a hydrogen storage alloy.

In an embodiment of the present invention, the hydrogen storage alloy has a chemical formula whose entire composition is represented by TiFe _1-y M _y , wherein M includes Cr and Mn, wherein the content of Mn is greater than the content of Cr, The y may be 0.05 to 0.3.

In an embodiment of the present invention, when the content of Mn is greater than the content of Cr, the residual amount of hydrogen after hydrogen release may be reduced than when the content of Mn is less than the content of Cr.

In order to achieve the above technical object, another embodiment of the present invention provides a hydrogen storage alloy.

In an embodiment of the present invention, the hydrogen storage alloy is an AB-based alloy matrix; and an AB _n alloy phase precipitated on the AB-based alloy matrix, wherein A and B are metals, and n may satisfy the condition 4≤n≤6.

In an embodiment of the present invention, in the AB _n -based alloy phase, A may include a rare earth element, and B may include a transition metal.

In order to achieve the above technical object, another embodiment of the present invention provides a method for activating a hydrogen storage alloy.

In an embodiment of the present invention, the method for activating a hydrogen storage alloy includes: charging an ingot of the hydrogen storage alloy in a hydrogen storage alloy tank and then sealing; evacuating the sealed hydrogen storage alloy tank; and injecting hydrogen into the vacuum hydrogen storage alloy tank to activate the hydrogen storage alloy. includes

In an embodiment of the present invention, the step of activating the hydrogen storage alloy may be performed at room temperature.

In an embodiment of the present invention, the step of activating the hydrogen storage alloy may be performed at a hydrogen pressure of 10 bar to 100 bar.

According to an embodiment of the present invention, by controlling the composition by adding Cr or Mn so that a Laves structure is partially formed in the AB-based alloy matrix, activation at room temperature is possible without performing the conventional high-temperature activation process. It is possible to provide a hydrogen storage alloy capable of absorbing hydrogen.

In addition, as Cr or Mn is added more within a certain content range, the fraction of the rabeth phase is increased and the Fe content in the composition of the raves phase is decreased, thereby improving the activation characteristics.

In addition, when both Cr and Mn are included, and the content of Mn is controlled to be greater than the content of Cr, the slope of the flattening pressure may be reduced so that the residual amount of hydrogen may be reduced when hydrogen is released.

The effects of the present invention are not limited to the above effects, and it should be understood to include all effects that can be inferred from the configuration of the invention described in the detailed description or claims of the present invention.

1 is an SEM image of a hydrogen storage alloy (FIG. 1 (a) Preparation Example 1 and FIG. 1 (b) Preparation Example 2) according to an embodiment of the present invention.
2 is an XRD graph of a hydrogen storage alloy (Preparation Example 1 and Preparation Example 2) according to an embodiment of the present invention.
3 is a graph of hydrogen adsorption per unit time of a hydrogen storage alloy according to an embodiment of the present invention.
4 is an XRD graph of Comparative Examples 1 to 4 according to an embodiment of the present invention.
5 is an SEM image of a hydrogen storage alloy (Preparation Examples 3 to 5) according to an embodiment of the present invention.
6 is a graph showing hydrogen adsorption per unit time of (a) a hydrogen storage alloy according to an embodiment of the present invention. (b) pct diagram of hydrogen storage alloy.
7 is a pct diagram of a hydrogen storage alloy according to an embodiment of the present invention.

Hereinafter, the present invention will be described with reference to the accompanying drawings. However, the present invention may be embodied in several different forms, and thus is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

Throughout the specification, when a part is "connected (connected, contacted, coupled)" with another part, it is not only "directly connected" but also "indirectly connected" with another member interposed therebetween. "Including cases where In addition, when a part "includes" a certain component, this means that other components may be further provided without excluding other components unless otherwise stated.

The terms used herein are used only to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present specification, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It is to be understood that this does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

A hydrogen storage alloy according to an embodiment of the present invention will be described.

1 is an SEM image of a hydrogen storage alloy according to an embodiment of the present invention.

Referring to Figure 1, the hydrogen storage alloy according to an embodiment of the present invention, AB-based alloy matrix; and an AB _m alloy phase having a Laves structure deposited on the AB-based alloy matrix, wherein A and B are metals, and m is characterized in that 1.2≤m≤2.5 conditions are satisfied.

The AB-based alloy matrix is an alloy composed of a stoichiometric ratio of A component metal (metal A) and B component metal (metal B) of 1:1. Its crystal structure may have, for example, a Cubic (cubic) structure, and may form a hydride of ABH ₂ .

The AB _m alloy phase is an alloy composed of a stoichiometric ratio of A component metal (metal A) and B component metal (metal B) of 1:1.2 to 2.5.

In the present specification, the terms Laves structure and Laves phase may be used as the same meaning.

The AB _m alloy phase has a Laves structure, and in general, an alloy having a Laves phase is an AB ₂ -based alloy. Although the AB _m alloy phase of the present invention has an atomic fraction of A and B not exactly 1:2, it has a Labes structure like the AB _two -based alloy.

Since the metal A shows a high chemical affinity with hydrogen, it forms a stable hydride, whereas the metal B is a component enabling a reversible reaction by lowering the stability of the hydride.

If metal A is excessive, hydrogen release is difficult because hydrogen is held too strongly, and if metal B is excessive, hydrogen may not be absorbed well, so there is a need to prepare a hydrogen storage alloy in an appropriate ratio.

In the AB-based alloy matrix, A may include Ti (titanium), Zr (zirconium) or V (vanadium), and B may include Fe (iron).

As a specific example, the AB-based alloy matrix may be a TiFe alloy matrix.

For example, when a part of Ti is substituted with Zr, hydrogen absorption capacity may be improved and cycle performance may be improved.

For example, when a part of Ti is substituted with V, the activation characteristic may be improved.

In the AB _m alloy phase, A may include Ti, Zr, or V, and B may include at least one selected from Cr (chromium) and Mn (manganese).

In addition, the B may further include Fe.

In addition, B may further include Co, Ni, Cu or Al.

For example, the AB _m alloy phase may include TiCr-based, TiFeCr-based, TiMn-based, TiFeMn-based, TiCrMn-based, TiFeCrMn-based, Ti(V)FeCr-based, or Ti(Zr)FeMn-based.

For example, when the AB-based alloy matrix is TiFe, the Cr or Mn may substitute a part of Fe to form an AB _m alloy phase of a Laves structure, and the AB _m alloy phase is partially precipitated on the TiFe alloy matrix it can be

TiFe alloy has better hydrogen storage capacity than LaNi ₅ , which is generally used as a hydrogen storage alloy, and there is almost no degradation in performance even in repeated reversible reactions that adsorb and release hydrogen, and it is much more economical in terms of price.

However, in order to utilize the TiFe alloy, a thin oxide film is formed by crushing the alloy ingot or exposed to the atmosphere in the process of being charged in a storage alloy tank, and hydrogen is not absorbed by the oxide film. Therefore, in the conventional TiFe alloy, an activation process at a high temperature (about 400° C. or higher), which is a process for removing the surface oxide film by high-temperature heat treatment, is essential, and since this is done at a high temperature, the load on the durability of the container is increased. and there was a problem in that the cost of the process increased.

Accordingly, the AB-based alloy matrix of the present invention; and an AB _m alloy phase having a Laves structure precipitated on the AB-based alloy matrix, wherein m provides a hydrogen storage alloy satisfying the condition 1.2≤m≤2.5, enabling activation at room temperature without a high temperature activation process to be able to absorb hydrogen.

The AB _m alloy phase has a Labes structure similar to that of the AB ₂ system, and has no problem in hydrogen absorption despite the presence of a surface oxide film.

Therefore, the AB _m alloy phase deposited on the AB-based alloy matrix acts as a hydrogen absorption channel to absorb hydrogen into the hydrogen storage alloy, and the volume expansion of the material and hydrogen embrittlement by the hydrogen absorbed through the AB _m alloy phase As the AB-based alloy material is cracked, an unoxidized surface appears, and after receiving the first hydrogen, hydrogen can be absorbed by the AB alloy matrix. That is, activation becomes possible at room temperature (low temperature).

The room temperature may mean a temperature of 20° C. to 25° C., but may include a temperature range of 10° C. to 100° C., which is relatively low compared to the prior art.

The hydrogen storage alloy according to another embodiment of the present invention has a chemical formula whose entire composition is represented by TiFe _1-x M _x , wherein M is a metal substituting a part of Fe and includes at least one selected from Cr and Mn and x is greater than 0 and less than or equal to 0.3.

By substituting a portion of Fe with Cr or Mn to form a Laves phase partially on the TiFe matrix, the activation characteristic is greatly improved compared to the conventional TiFe.

Part or all of Ti may be substituted with Zr.

By the Zr substitution, hydrogen absorption capacity may be improved and cycle performance may be improved.

In addition, part or all of Ti may be substituted with V.

Activation characteristics may be improved by the V substitution.

In addition, a part of Fe may be substituted with Co, Ni, Cu or Al.

When the atomic fraction x of M is greater than 0.3, the flat pressure may be too low to make it difficult to release hydrogen.

For example, the TiFe _1-x M _x may be TiFe _0.8 Cr _0.2 or TiFe _0.8 Mn _0.2 , may include Cr and Mn simultaneously, and any combination within the fraction of M (more than 0 and less than or equal to 0.3) It is possible.

As the content of M (Cr, Mn, or a mixture thereof) increases within the x range, the activation characteristic may increase.

This is because, as the content of Cr or Mn increases, the area of the Laves phase deposited on the AB alloy matrix increases.

The hydrogen storage alloy according to another embodiment of the present invention has a chemical formula whose entire composition is represented by TiFe _1-y M _y , wherein M includes both Cr and Mn, wherein the Mn content is greater than the Cr content , y is characterized in that 0.05 to 0.3.

Part or all of Ti may be substituted with Zr.

By the Zr substitution, hydrogen absorption capacity may be improved and cycle performance may be improved.

In addition, part or all of Ti may be substituted with V.

Activation characteristics may be improved by the V substitution.

In addition, a part of Fe may be substituted with Co, Ni, Cu or Al.

If the atomic fraction y of M is less than 0.05, Cr and Mn may not satisfy the condition for forming a Laves phase while simultaneously replacing Fe. can

For example, the TiFe _1-y M _y may be TiFe _0.7 Cr _0.1 Mn _0.2 , and contains Cr and Mn at the same time and has a higher Mn content, and any combination is possible within the fraction of M (0.05 to 0.3). do.

When the content of Mn is greater than the content of Cr, the slope of the flat pressure may be smaller than when the content of Mn is less than the content of Cr (see FIG. 7 ).

That is, the slope of the flat pressure is flattened, so that a larger amount can be emitted even when the same temperature is raised when the hydrogen is released, so that the residual amount of hydrogen after hydrogen release is reduced, so that more hydrogen can be used with the same volume of hydrogen storage alloy there is an effect

In addition, as the Cr and Mn content increases, the activation characteristic may increase. This is because, as Cr and Mn are added, the fraction of the Raves phase is increased first, and the Fe content in the composition of the Raves phase is decreased and the activation characteristics are improved. However, the total content of Cr and Mn can be controlled within an atomic fraction of 0.05 to 0.3.

Hydrogen storage alloy according to another embodiment of the present invention, AB-based alloy base; and an AB _n alloy phase precipitated on the AB-based alloy matrix, wherein A and B are metals, and n is characterized in that 4≤n≤6 conditions are satisfied.

The AB _n alloy phase is an alloy composed of a stoichiometric ratio of A component metal (metal A) and B component metal (metal B) of 1: 4-6.

In the AB _n alloy phase, A may include a rare earth element, and B may include a transition metal.

For example, A may include La (lanthanum), Ce (cerium), or Mischmetal.

For example, B may include Ni (nickel), cobalt (Co), manganese (Mn), or aluminum (Al).

As a specific example, the AB _n alloy phase may be LaNi ₅ .

For example, when the AB-based alloy matrix is TiFe, LaNi ₅ may be partially precipitated in the TiFe alloy matrix by substituting a part of the Ti and Ni substituting a part of the Fe.

Although the atomic fraction of A and B may not be exactly 1:5 in the AB _n alloy phase, it has a structure similar to that of the AB ₅ system and has a characteristic that hydrogen absorption is not disturbed despite the presence of a surface oxide film.

Therefore, the AB _n alloy phase deposited on the AB-based alloy matrix acts as a hydrogen absorption channel to absorb hydrogen into the hydrogen storage alloy, and the volume expansion of the material and hydrogen embrittlement by the hydrogen absorbed through the AB _n alloy phase As the AB-based alloy material is cracked, an unoxidized surface appears, and after receiving the first hydrogen, the AB alloy matrix can also absorb hydrogen. That is, activation becomes possible at room temperature (low temperature).

The room temperature may mean a temperature of 20° C. to 25° C., but may include a temperature range of 10° C. to 100° C., which is relatively low compared to the prior art.

A method of activating a hydrogen storage alloy according to another embodiment of the present invention will be described.

A method for activating a hydrogen storage alloy according to another embodiment of the present invention includes the steps of charging an ingot of the hydrogen storage alloy of the present invention into a hydrogen storage alloy tank and then sealing (S100); evacuating the sealed hydrogen storage alloy tank (S200); and injecting hydrogen into the vacuum hydrogen storage alloy tank to activate the hydrogen storage alloy (S300); includes

In the first step, the ingot of the hydrogen storage alloy of the present invention described above is charged and then sealed in the hydrogen storage alloy tank (S100).

If the ingot of the hydrogen storage alloy is too large to be charged in the hydrogen storage alloy tank, it may be pulverized.

The ingot may be charged into the tank and protected from the external environment by shielding the tank.

However, a thin oxide film is formed on the surface of the pulverized hydrogen storage alloy as it is already exposed to the atmosphere while the hydrogen storage alloy is pulverized or charged in a tank. Conventionally, high-temperature heat treatment was required to remove the oxide film, but the hydrogen storage alloy of the present invention has an AB _m alloy phase or AB _n alloy phase region, which is a passage through which hydrogen can be stored (absorbed) even when an oxide film is formed. There is no need for an activation process at a high temperature (over about 400°C).

In the second step, the sealed hydrogen storage alloy tank is evacuated (S200).

Prepare for easy reaction with hydrogen by maintaining a vacuum inside the hydrogen storage alloy tank.

In the third step, hydrogen is injected into the vacuum hydrogen storage alloy tank to activate the hydrogen storage alloy (S300).

The hydrogen is injected and reacts with the hydrogen storage alloy in the tank to enable storage of hydrogen in the hydrogen storage alloy.

The step of activating the hydrogen storage alloy may be performed at room temperature.

The room temperature may mean a temperature of 20° C. to 25° C., but may include a temperature range of 10° C. to 100° C., which is relatively low compared to the prior art.

The hydrogen storage alloy of the present invention is an alloy in which an AB _m alloy phase or an AB _n alloy phase is precipitated on an AB-based alloy matrix, and the AB _m alloy phase or AB _n alloy phase may be partially present in the AB-based alloy matrix. Although the AB-based alloy matrix on which the oxide film is formed before absorbing hydrogen for the first time cannot absorb hydrogen without a high-temperature activation process (removing the oxide film by high-temperature heat treatment), the AB _m alloy phase or AB _n alloy phase is hydrogen despite the formation of an oxide film. Since it can absorb hydrogen, it acts as a hydrogen absorption channel and _absorbs hydrogen into the hydrogen _storage alloy. As the alloy material cracks, an unoxidized surface appears, allowing hydrogen to be absorbed by the AB alloy matrix after accepting the first hydrogen. That is, activation becomes possible at room temperature (low temperature).

In addition, the step of activating the hydrogen storage alloy may be performed at a hydrogen pressure of 10 bar to 100 bar.

When the hydrogen pressure is less than 10 bar, activation may be difficult because the pressure is too low, and when the hydrogen pressure is greater than 100 bar, an excessive pressure than the actual hydrogen storage pressure may be used.

For example, the step of activating the hydrogen storage alloy may be performed for 2 hours at a temperature of 25° C. and a hydrogen pressure of 60 bar.

When hydrogen is subsequently used, the hydrogen atoms in the alloy can be released back into hydrogen gas by lowering the pressure inside the tank or raising the temperature.

Hereinafter, the present invention will be described in more detail through Preparation Examples, Comparative Examples and Experimental Examples. However, the present invention is not limited to the following Examples and Experimental Examples.

Preparation Example 1

50at% of Ti, 40at% of Fe, and 10at% of Mn were weighed, respectively, put into a crucible, heated and cooled to prepare a TiFe _0.8 Mn _0.2 hydrogen storage alloy having a Labes phase partially precipitated on a TiFe alloy matrix.

Production Example 2

50at% of Ti, 40at% of Fe, and 10at% of Cr were weighed, respectively, put into a crucible, heated and cooled to prepare a TiFe _0.8 Cr _0.2 hydrogen storage alloy having a Labes phase partially precipitated on a TiFe alloy matrix.

Production Example 3

TiFe _0.85 Cr _0.1 Mn _0.05 Hydrogen with 50at% of Ti, 42.5at% of Fe, 5at% of Cr and 2.5at% of Mn, respectively, weighed, put into a crucible, heated and cooled, and have a Labes phase partially precipitated on a TiFe alloy matrix A storage alloy was prepared.

Preparation 4

TiFe _0.8 Cr _0.1 Mn _0.1 hydrogen storage alloy having a labes phase partially precipitated on a TiFe alloy matrix by weighing 50at% of Ti, 40at% of Fe, 5at% of Cr, and 5at% of Mn, respectively, putting it into a crucible, heating it, and cooling it was prepared.

Production Example 5

TiFe _0.7 Cr _0.1 Mn _0.2 hydrogen storage alloy having a Labes phase partially precipitated on a TiFe alloy matrix by weighing 50at% of Ti, 35at% of Fe, 5at% of Cr, and 10at% of Mn, respectively, putting it into a crucible, heating it, and cooling it was prepared.

Comparative Example 1

TiFe _0.7 Ni _0.3 hydrogen storage alloy was prepared by weighing 50 at% Ti, 35 at% Fe, and 15 at% Ni, respectively, putting them into a crucible, heating and cooling.

Comparative Example 2

Each of Ti 50at%, Fe 35at% and Co 15at% was weighed, put into a crucible, heated and cooled to prepare a TiFe _0.7 Co _0.3 hydrogen storage alloy.

Comparative Example 3

Each of Ti 50at%, Fe 35at% and Cu 15at% was weighed, put into a crucible, heated, and cooled to prepare a TiFe _0.7 Cu _0.3 hydrogen storage alloy.

Comparative Example 4

TiFe _0.7 Al _0.3 hydrogen storage alloy was prepared by weighing 50 at% Ti, 35 at% Fe, and 15 at% Al, respectively, putting it into a crucible, heating it, and cooling it.

Experimental example

1 is an SEM image of a hydrogen storage alloy (FIG. 1 (a) Preparation Example 1 and FIG. 1 (b) Preparation Example 2) according to an embodiment of the present invention.

Referring to FIG. 1 , in Preparation Examples 1 and 2, it can be seen that the Laves phase (bright region) was partially precipitated on the TiFe alloy matrix (dark region).

2 is an XRD graph of a hydrogen storage alloy (Preparation Example 1 and Preparation Example 2) according to an embodiment of the present invention.

Referring to FIG. 2 , it can be seen that a Laves structure peak was formed in Preparation Examples 1 and 2.

3 is a graph of hydrogen adsorption per unit time of a hydrogen storage alloy according to an embodiment of the present invention.

Referring to FIG. 3 , the initial activation characteristics of hydrogen were measured using a pressure-concentration-temperature (PCT) device that analyzes hydrogen absorption/release behavior. First, TiFe single-phase alloy, Preparation Example 1 and Preparation Example 2 were each independently charged and evacuated at room temperature for 30 minutes, then 40 bar of hydrogen was applied and maintained for 2 hours. It can be seen that the TiFe single phase did not absorb hydrogen at all (since it was not subjected to high-temperature activation heat treatment), and the hydrogen storage alloy in which Cr or Mn was added to precipitate the Laves phase showed much better hydrogen absorption. In the case of Cr, compared to Mn, the initial absorption is very fast, and Mn has the characteristic of gradually absorbing hydrogen.

4 is an XRD graph of Comparative Examples 1 to 4 according to an embodiment of the present invention.

Referring to FIG. 4 , it can be confirmed that in Comparative Examples 1 to 4, the Labes phase was not formed. That is, only the AB-based single phase was formed, and the Labes phase was not formed.

5 is an SEM image of a hydrogen storage alloy (Preparation Examples 3 to 5) according to an embodiment of the present invention.

Referring to FIG. 5, a hydrogen storage alloy was prepared by fixing Cr to 0.1 (atomic fraction), increasing the Mn content and decreasing the Fe content. In Preparation Examples 3 to 5, it can be seen that the Laves phase (light region) was partially precipitated on the TiFe alloy matrix (dark region). The total atomic fraction of Mn and Cr of Preparation Example 3 is 0.15, the total atomic fraction of Mn and Cr of Preparation Example 4 is 0.2, and the total atomic fraction of Mn and Cr of Preparation Example 5 is 0.3. As a result, looking at the area of the precipitated raves phase, it can be seen that Preparation Example 5 has the largest number.

6 is a graph showing hydrogen adsorption per unit time of (a) a hydrogen storage alloy according to an embodiment of the present invention. (b) pct diagram of hydrogen storage alloy.

Referring to FIG. 6, after charging the hydrogen storage alloy for each content in FIG. 6(a) and performing vacuum evacuation at room temperature for 30 minutes, 40 bar of hydrogen was applied and maintained for 2 hours. Among them, it can be seen that Preparation Example 5, which has the highest total content of Cr and Mn, has the fastest hydrogen absorption and the best absorption capacity, and thus it can be confirmed that the activation characteristic of Preparation Example 5 is the best.

FIG. 6(b) is a pct diagram of a hydrogen storage alloy in which Cr and Mn contents are the same at an atomic fraction of 0.15, respectively. It can be seen that the residual amount of hydrogen in the hydrogen storage alloy in which the Cr and Mn content is 0.15 atomic fraction (1:1), respectively, is 0.6wt%.

7 is a pct diagram of a hydrogen storage alloy according to an embodiment of the present invention.

Referring to FIG. 7 , analyzing the pct diagram taken at 60° C., it can be confirmed that the hydrogen storage alloy containing Cr and Mn in an atomic fraction of 1:4 has a gentle slope of flat pressure, leaving a residual amount of hydrogen of 0.3wt%. . This indicates that hydrogen is easily released compared to the hydrogen storage alloy in which Cr and Mn in FIG. 6(b) have a 1:1 atomic fraction.

According to an embodiment of the present invention, by controlling the composition by adding Cr or Mn so that a Laves structure is partially formed in the AB-based alloy matrix, activation at room temperature is possible without performing the conventional high-temperature activation process. It is possible to provide a hydrogen storage alloy capable of absorbing hydrogen.

In addition, as Cr or Mn is added more within a certain content range, the fraction of the rabeth phase is increased and the Fe content in the composition of the raves phase is decreased, thereby improving the activation characteristics.

In addition, when both Cr and Mn are included, and the content of Mn is controlled to be greater than the content of Cr, the slope of the flattening pressure may be reduced so that the residual amount of hydrogen may be reduced when hydrogen is released.

The foregoing description of the present invention is for illustration, and those of ordinary skill in the art to which the present invention pertains can understand that it can be easily modified into other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and likewise components described as distributed may also be implemented in a combined form.

The scope of the present invention is indicated by the following claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention.

Claims (14)

delete delete delete delete delete delete delete The entire composition has a chemical formula represented by TiFe _1-y M _y , wherein M includes Cr and Mn, wherein the content of Mn is greater than the content of Cr, and y is 0.05 to 0.3. . 9. The method of claim 8,
When the content of Mn is greater than the content of Cr, the hydrogen storage alloy, characterized in that the residual amount of hydrogen after hydrogen release is reduced than when the content of Mn is less than the content of Cr. delete delete The method of claim 8 or 9, wherein the ingot of the hydrogen storage alloy of any one of claims 8 or 9 is charged and then sealed in a hydrogen storage alloy tank;
evacuating the sealed hydrogen storage alloy tank; and
activating the hydrogen storage alloy by injecting hydrogen into the vacuum hydrogen storage alloy tank; Activation method of a hydrogen storage alloy comprising a. 13. The method of claim 12,
Activating the hydrogen storage alloy is a method of activating a hydrogen storage alloy, characterized in that performed at room temperature. 13. The method of claim 12,
Activating the hydrogen storage alloy is a method of activating a hydrogen storage alloy, characterized in that performed at a hydrogen pressure of 10 bar to 100 bar.

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