Stabilized aluminum hydride compound and preparation method thereof

Abstract

The invention provides a stabilized aluminum hydride compound and a preparation method thereof, and belongs to the technical field of hydrogen storage materials. The stabilized aluminum hydride compound provided by the invention comprises the following components in parts by mass: 100 parts of aluminum hydride and a coating agent, the coating agent is prepared from 1-15 parts of polycyclic aromatic hydrocarbon with an electron-donating group and 30-100 parts of an alkaline solution. According to the invention, the polycyclic aromatic hydrocarbon of the electron-donating group is adopted to treat the aluminum hydride to prepare the stabilized aluminum hydride compound, so that the thermal stability of the aluminum hydride is improved. The stabilized aluminum hydride compound provided by the invention also has good stability under the condition of long-term storage, and provides powerful guarantee for long-term storage and transportation of aluminum hydride. The preparation method of the stabilized aluminum hydride compound is simple and easy for industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen storage materials, and in particular to a stabilized aluminum hydride composite and a preparation method thereof. Background Art

[0002] Aluminum hydride (AlH3) is a highly promising hydrogen storage material, attracting significant attention due to its high mass hydrogen storage capacity and volumetric hydrogen storage density. Its mass hydrogen storage density is significantly higher than that of traditional high-pressure hydrogen storage and some metal hydrides, making it a preferred material for fuel cells, microelectronics, and aerospace propellants. However, AlH3 suffers from poor thermal stability and is highly sensitive to moisture and oxygen in the air. It is prone to slow decomposition during storage, leading to hydrogen loss and performance degradation, which severely restricts its industrial application.

[0003] To solve this problem, current research has proposed a variety of stabilization approaches, including surface coating, surface passivation and doping. Surface coating is a method that is currently widely used. By coating an organic or inorganic coating layer on the surface of aluminum hydride, it can effectively isolate external water and oxygen, thereby improving its stability. For example, CN104046957B uses atomic layer deposition technology to deposit nanometer or submicron thickness of metal oxide or metal material on the surface of aluminum hydride powder to coat it, in order to improve the thermal stability of aluminum hydride powder. However, the current coating method still has certain limitations during long-term storage, and the coating layer may be defective due to environmental changes, resulting in a decrease in the stability of aluminum hydride.

[0004] In summary, although surface coating and other technologies have made some progress in improving the stability of aluminum hydride, its long-term storage stability still needs to be further improved. Therefore, developing a new method to maintain the stability of aluminum hydride during long-term storage is of great significance for its widespread application in fields such as hydrogen storage and energetic materials. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the present invention discloses a stabilized aluminum hydride compound and a preparation method thereof, so as to solve the problems of poor thermal stability of aluminum hydride and decreased stability during long-term storage.

[0006] To solve at least one of the above problems, on the one hand, the present invention provides a stabilized aluminum hydride complex, comprising, by mass: 100 parts of aluminum hydride and a coating agent; the coating agent is prepared from 1-15 parts of a condensed aromatic hydrocarbon having an electron-donating group and 30-100 parts of an alkaline solution.

[0007] In the stabilized aluminum hydride complex proposed by the present invention, the coating agent is prepared from a condensed aromatic hydrocarbon with an electron-donating group and an alkaline solution. The complex formed between the condensed aromatic hydrocarbon with an electron-donating group and the aluminum hydride, along with the surface modification of the aluminum hydride by the alkaline solution, improves the thermal stability and long-term storage stability of the aluminum hydride.

[0008] In some embodiments, the stabilized aluminum hydride complex comprises, by mass: 100 parts of aluminum hydride and a capping agent; the capping agent is prepared from 2-15 parts of a condensed aromatic hydrocarbon having an electron-donating group and 50-100 parts of an alkaline solution.

[0009] In some embodiments, the fused ring aromatic hydrocarbon having an electron-donating group includes one or more of anthracene, naphthalene, and phenanthrene derivatives.

[0010] In some embodiments, the fused-ring aromatic hydrocarbon having an electron-donating group includes one or more of 9-anthryl alcohol, 9-methylanthracene, 9-aminoanthracene, 2-(tert-butyl)anthracene, α-naphthylamine, 1,6-diethylnaphthalene, 2,6-di-tert-butylnaphthalene, and 3-phenanthrenylamine.

[0011] In some embodiments, the fused-ring aromatic hydrocarbon having an electron-donating group includes one or more of 9-aminoanthracene, 2-(tert-butyl)anthracene, and 1,6-diethylnaphthalene.

[0012] In some embodiments, the alkaline solution is an aqueous solution of an alkali, and the alkali is selected from one or more of sodium carbonate, sodium bicarbonate, and sodium hydroxide.

[0013] In some embodiments, the concentration of the alkaline solution is 1%-20%.

[0014] On the other hand, the present invention also provides a method for preparing the stabilized aluminum hydride complex as described in the first aspect, comprising the following steps:

[0015] (1) At room temperature, a condensed aromatic hydrocarbon with an electron-donating group and an alkaline solution are mixed uniformly in proportion to prepare a coating agent;

[0016] (2) Under nitrogen protection, the coating agent is infiltrated dropwise onto the surface of aluminum hydride at room temperature, and then the temperature is raised to 30-70°C and stirred for 1-8 hours. After washing, filtering, and drying, a stabilized aluminum hydride complex is obtained.

[0017] In some embodiments, the washing solvent in step (2) is one or more of ethyl acetate, acetone, ether, ethanol, dichloromethane, tetrahydrofuran, carbon tetrachloride or carbon disulfide.

[0018] In some embodiments, the drying temperature in step (2) is 30-60° C., and the drying time is 2-8 hours.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The present invention uses condensed ring aromatic hydrocarbons with electron-donating groups to treat aluminum hydride to prepare a stabilized aluminum hydride complex, thereby improving the thermal stability of aluminum hydride.

[0021] (2) The stabilized aluminum hydride complex of the present invention also has good stability under long-term storage conditions, providing a strong guarantee for the long-term storage and transportation of aluminum hydride.

[0022] (3) The preparation method of the stabilized aluminum hydride complex of the present invention is simple and easy to industrialize. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0024] Figure 1 FTIR graphs of Example 1, Example 2 and Comparative Example 2 of the present invention are shown.

[0025] Figure 2 The XRD patterns of Example 1, Example 2 and Comparative Example 2 of the present invention are shown.

[0026] Figure 3 SEM images of Example 1, Example 2 and Comparative Example 2 of the present invention are shown; wherein, (a) is the SEM image of Example 1, (b) is the SEM image of Comparative Example 2, and (c) is the SEM image of Example 2.

[0027] Figure 4 TG curves of Example 1, Example 2, Comparative Example 1 and the samples after storage for one year are shown. DETAILED DESCRIPTION

[0028] To facilitate understanding of the present invention, the present invention will be described in more detail below, with preferred embodiments of the present invention provided. However, it should be understood that these embodiments are merely for the purpose of further explanation and are not to be construed as limiting the present invention in any form, i.e., they are not intended to limit the scope of protection of the present invention.

[0029] Unless otherwise defined, the technical terms used in the following examples have the same meanings as commonly understood by those skilled in the art to which this invention belongs. The experimental reagents used in the following examples, unless otherwise specified, are conventional biochemical reagents; the experimental methods described, unless otherwise specified, are conventional methods.

[0030] Example 1

[0031] A method for preparing a stabilized aluminum hydride complex comprises the following steps:

[0032] (1) Dissolve 2 parts of 9-methylanthracene in 50 parts of 5% sodium bicarbonate alkaline solution at room temperature, mix well, and prepare a coating agent;

[0033] (2) Under nitrogen protection, the coating agent prepared in step (1) was dropwise infiltrated onto the surface of 100 parts of aluminum hydride using a constant pressure funnel at room temperature within 2 hours, the temperature was raised to 50°C and stirred for 4 hours, the mixture was washed 5 times with dehydrated ethyl acetate and filtered, and dried in a vacuum oven at 60°C for 4 hours to obtain a stabilized aluminum hydride complex A.

[0034] Example 2

[0035] A method for preparing a stabilized aluminum hydride complex comprises the following steps:

[0036] (1) Dissolve 5 parts of 2-(tert-butyl)anthracene in 50 parts of a 5% sodium bicarbonate alkaline solution at room temperature, mix well, and prepare a coating agent;

[0037] (2) Under nitrogen protection, the coating agent prepared in step (1) was dropwise infiltrated onto the surface of 100 parts of aluminum hydride using a constant pressure funnel at room temperature within 2 hours, the temperature was raised to 60°C and stirred for 4 hours, the mixture was washed 5 times with dehydrated ethyl acetate and filtered, and dried in a vacuum oven at 50°C for 6 hours to obtain a stabilized aluminum hydride complex B.

[0038] Example 3

[0039] A method for preparing a stabilized aluminum hydride complex comprises the following steps:

[0040] (1) Dissolve 15 parts of 1,6-diethylnaphthalene in 100 parts of a 5% sodium carbonate alkaline solution at room temperature, mix well, and prepare a coating agent;

[0041] (2) Under nitrogen protection, the coating agent prepared in step (1) was dropwise infiltrated onto the surface of 100 parts of aluminum hydride using a constant pressure funnel at room temperature within 4 hours, the temperature was raised to 50°C and stirred for 3 hours, the mixture was washed 5 times with dehydrated acetone, and then filtered, and dried in a vacuum oven at 50°C for 6 hours to obtain a stabilized aluminum hydride complex C.

[0042] Example 4

[0043] A method for preparing a stabilized aluminum hydride complex comprises the following steps:

[0044] (1) Dissolve 10 parts of 1,6-diethylnaphthalene in 100 parts of a 5% sodium carbonate alkaline solution at room temperature, mix well, and prepare a coating agent;

[0045] (2) Under nitrogen protection, the coating agent prepared in step (1) was dropwise infiltrated onto the surface of 100 parts of aluminum hydride using a constant pressure funnel at room temperature within 2 hours, the temperature was raised to 50°C and stirred for 5 hours, the mixture was washed 5 times with dehydrated acetone, and then filtered, and dried in a vacuum oven at 40°C for 8 hours to obtain a stabilized aluminum hydride complex D.

[0046] Comparative Example 1

[0047] This comparative example is aluminum hydride without any treatment.

[0048] Comparative Example 2

[0049] This comparative example uses electron-withdrawing fused-ring aromatic hydrocarbon 9-nitroanthracene to prepare a complex of aluminum hydride, comprising the following steps:

[0050] (1) Dissolve 10 parts of 9-nitroanthracene in 70 parts of a 1% sodium hydroxide alkaline solution at room temperature, mix well, and prepare a coating agent;

[0051] (2) Under nitrogen protection, the coating agent prepared in step (1) was dropwise infiltrated onto the surface of 100 parts of aluminum hydride using a constant pressure funnel at room temperature within 3 hours, the temperature was raised to 40°C and stirred for 6 hours, the mixture was washed four times with dehydrated toluene and then filtered, and dried in a vacuum oven at 40°C for 8 hours to obtain a stabilized aluminum hydride complex E.

[0052] Test Example 1

[0053] The stabilized aluminum hydride complexes A, B, and E prepared in Example 1, Example 2, and Comparative Example 2 were tested using an infrared spectrometer. The FTIR images obtained were as follows: Figure 1 shown.

[0054] Depend on Figure 1 It can be seen that in the range of 650-1000cm -1 The out-of-plane stretching vibration peak of CH is 1130-1475 cm -1 The in-plane stretching vibration peak of CH is 1450-1620cm -1 The characteristic peak of the benzene ring skeleton in the aromatic hydrocarbon structure is 1650-1755cm -1 The characteristic peak of the carbonyl group in the benzene structure is 3000cm -1 The stretching vibration peak of CH on saturated carbon is at 1300-1400 cm -1 and at 1500-1690cm -1 There are characteristic peaks at these two locations that are obviously different from the first two anthracenes. These two are characteristic peaks of nitro groups.

[0055] Test Example 2

[0056] The stabilized aluminum hydride complexes A, B, and E prepared in Example 1, Example 2, and Comparative Example 2 were tested using an X-ray diffractometer. The XRD spectra obtained from the test are shown in FIG. Figure 2 shown.

[0057] Depend on Figure 2 It can be seen that 2θ = 27.1°, 37.9°, 40.0°, 45.6°, 49.2°, 56.6°, 62.5°, 65.5° and 67.5° correspond to the (012), (111), (110), (006), (202), (024), (116), (122) and (018) crystal planes of α-AlH3, respectively. The impurity peaks at 2θ = 15.3° and 31.4° may originate from the aluminum oxide produced by the partially oxidized aluminum hydride powder. The unit cell parameters of AlH3 are calculated to be: α = 90°, β = 90°, γ = 120°; by comparison, the crystal structure of AlH3 in stabilized aluminum hydride complexes A and B prepared using 9-methylanthracene and 2-(tert-butyl)anthracene did not change, indicating that the interaction between 9-methylanthracene and 2-(tert-butyl)anthracene and AlH3 did not significantly affect the crystal structure of AlH3. In contrast, the crystallization peak intensity of AlH3 in stabilized aluminum hydride complex E prepared using 9-nitroanthracene decreased, with some peaks decreasing or even disappearing, indicating that 9-nitroanthracene did affect AlH3.

[0058] The research team speculates that this result is primarily due to the electronic effect of substituents on AlH3: 9-methylanthracene, 2-(tert-butyl)anthracene, and 9-nitroanthracene differ primarily in their substituents. Methyl and tert-butyl groups are electron-donating groups, while the nitro group is an electron-withdrawing group. The electron-withdrawing nitro group may enhance the interaction between the anthracene compound and AlH3, thereby disrupting or altering the AlH3 crystal structure.

[0059] Test Example 3

[0060] The stabilized aluminum hydride complexes A, B, and E prepared in Example 1, Example 2, and Comparative Example 2 were tested using a scanning electron microscope. The SEM images obtained are shown in FIG. Figure 3 shown.

[0061] Depend on Figure 3 It can be seen that the surface morphologies of the stabilized aluminum hydride complexes A, B, and E prepared using 9-methylanthracene, 2-(tert-butyl)anthracene, and 9-nitroanthracene are somewhat different; the stabilized aluminum hydride complexes A and B prepared using 9-methylanthracene and 2-(tert-butyl)anthracene, such as Figure 3As shown in (a) and 3 (c), the surface morphology is uniform and there is a relatively thin layer of coverage. The stabilized aluminum trihydride complex E prepared using 9-nitroanthracene, such as Figure 3 As shown in (b), impurity bright spots appeared, which is consistent with the result of the change in the crystal form of aluminum hydride in XRD of Comparative Example 2 in Test Example 2, indicating that 9-nitroanthracene will destroy the structure of aluminum hydride, that is, the strong electron-withdrawing group is not conducive to the stability of aluminum hydride. Therefore, it is better to use condensed ring aromatic hydrocarbons with electron-donating effect substituents to coat aluminum hydride.

[0062] Test Example 4

[0063] The stabilized aluminum hydride complexes A and B prepared in Example 1 and Example 2, the aluminum hydride of Comparative Example 1, and the stabilized aluminum hydride complexes A and B and aluminum hydride after storage for one year were subjected to thermogravimetric analysis. The TG curve results are shown in FIG. Figure 4 shown.

[0064] The results in the figure show that, in the TG curve, at around 185°C, the aluminum hydride of Comparative Example 1 lost 9.7% of its weight. After one year of storage, the aluminum hydride of Comparative Example 1 lost 14.6% of its weight, a difference of 4.9%. The stabilized aluminum hydride composite A prepared in Example 1 lost 10.8% of its weight. After one year of storage, the stabilized aluminum hydride composite A lost 17.9% of its weight, a difference of 7.1%. The stabilized aluminum hydride composite B prepared in Example 2 lost 8.7% of its weight. After one year of storage, the stabilized aluminum hydride composite B lost 17.0% of its weight, a difference of 8.3%. Since 185°C is primarily the decomposition temperature for the release of hydrogen from aluminum hydride, a greater weight loss here indicates a greater hydrogen content. The above results show that both the unstabilized aluminum hydride of Comparative Example 1 and the stabilized aluminum hydride composites A and B prepared in Examples 1 and 2 experience increased weight loss after one year of storage. It is speculated that the increased weight loss, in addition to impurities such as water vapor adsorbed on the surface of aluminum hydride, is primarily due to the electron-deficient nature of aluminum hydride. This electron-deficient nature enables coordination with electron donors (such as 9-methylanthracene and 2-(tert-butyl)anthracene) to form kinetically and thermodynamically stable aluminum hydride complexes. This stabilization reduces aluminum hydride's reactivity by altering its electronic structure and chemical environment, thereby reducing its slow hydrogen release during the one-year storage period. Consequently, the increase in weight loss after one year of storage relative to the initial weight loss reflects, to a certain extent, the stabilization effect. Although the difference in weight loss appears to be greater for the stabilized composite, this does not mean that the stabilization effect is poor. Rather, it is because the effective hydrogen content of aluminum hydride in the stabilized composites A and B may be relatively high initially (as can be seen from the initial weight loss, the initial weight loss of Examples 1 and 2 is similar to or slightly higher than that of Comparative Example 1, indicating that the stabilization treatment did not significantly reduce the initial hydrogen content). During storage, the stabilization effect effectively inhibits the slow release of hydrogen, allowing more hydrogen to be retained after one year of storage, resulting in a relatively large difference in weight loss.

[0065] It should be noted that the above content is a further detailed description of the present invention in conjunction with specific implementation methods, and the specific implementation of the present invention cannot be considered to be limited to these descriptions; the experimental parameters of this embodiment do not necessarily limit the technical solution, but only illustrate one specific working condition. For those skilled in the art of the present invention, simple improvements and modifications can be made without departing from the concept of the present invention, and all of these should be considered to fall within the scope of protection of the present invention.

Claims

1. A stabilized aluminum hydride complex, characterized in that: The method comprises, by mass, 100 parts of aluminum hydride and a coating agent; the coating agent is prepared from 1-15 parts of condensed ring aromatic hydrocarbons having electron-donating groups and 30-100 parts of alkaline solution.

2. The stabilized aluminum hydride complex according to claim 1, characterized in that The method comprises, by mass, 100 parts of aluminum hydride and a coating agent; the coating agent is prepared from 2-15 parts of condensed ring aromatic hydrocarbons having electron-donating groups and 50-100 parts of alkaline solution.

3. The stabilized aluminum hydride complex according to claim 1, characterized in that The condensed ring aromatic hydrocarbon having an electron-donating group includes one or more of anthracene, naphthalene and phenanthrene derivatives.

4. The stabilized aluminum hydride complex according to claim 1, characterized in that The condensed ring aromatic hydrocarbons having an electron-donating group include one or more of 9-anthryl alcohol, 9-methylanthracene, 9-aminoanthracene, 2-(tert-butyl)anthracene, α-naphthylamine, 1,6-diethylnaphthalene, 2,6-di-tert-butylnaphthalene, and 3-phenanthrenylamine.

5. The stabilized aluminum hydride complex according to claim 1, characterized in that The condensed ring aromatic hydrocarbon having an electron-donating group includes one or more of 9-aminoanthracene, 2-(tert-butyl)anthracene, and 1,6-diethylnaphthalene.

6. The stabilized aluminum hydride complex according to claim 1, characterized in that The alkaline solution is an aqueous solution of alkali, and the alkali is selected from one or more of sodium carbonate, sodium bicarbonate, and sodium hydroxide.

7. The stabilized aluminum hydride complex according to claim 1, characterized in that The concentration of the alkaline solution is 1%-20%.

8. A method for preparing the stabilized aluminum hydride complex according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) At room temperature, a condensed aromatic hydrocarbon with an electron-donating group and an alkaline solution are mixed uniformly in proportion to prepare a coating agent; (2) Under nitrogen protection, the coating agent is infiltrated dropwise onto the surface of aluminum hydride at room temperature, and then the temperature is raised to 30-70°C and stirred for 1-8 hours. After washing, filtering, and drying, a stabilized aluminum hydride complex is obtained.

9. The preparation method according to claim 8, characterized in that The washing solvent in step (2) is one or more of ethyl acetate, acetone, ether, ethanol, dichloromethane, tetrahydrofuran, carbon tetrachloride or carbon disulfide.

10. The preparation method according to claim 8, characterized in that The drying temperature in step (2) is 30-60° C., and the drying time is 2-8 hours.

Images