Hydrogen storage material as well as preparation method and application thereof

Abstract

The invention relates to the field of hydrogen storage materials, in particular to a hydrogen storage material and a preparation method and application thereof. The hydrogen storage material VxMo1-xN provided by the invention is used as a solid hydrogen storage material, is high in hydrogen storage capacity, high in hydrogen storage rate and high in hydrogen storage stability, and has remarkable advantages in the field of vehicle-mounted solid hydrogen storage. Experiments show that by taking V0. 2Mo0. 8N as an example, 9.26 wt% of hydrogen can be reversibly absorbed / released within several minutes at 109.5 bar and 150 DEG C. And under the hydrogen pressure of 73.6 bar, 5.6 wt% of hydrogen can be absorbed within 30 seconds. More importantly, the V0. 2Mo0. 8N material shows excellent cycle stability, and has no capacity loss in 500 times of super-long cycles. At present, the material is not applied to the field of solid hydrogen storage by people, and material innovation and solid hydrogen storage performance are outstanding.

Description

Technical Field

[0001] This invention relates to the field of hydrogen storage materials, specifically hydrogen storage materials, their preparation methods, and applications. Background Technology

[0002] With the depletion of fossil fuels, hydrogen energy, as a green, clean, and renewable fuel, will become a major trend in future energy development. However, its practical application is limited by the difficulty of storing hydrogen due to its low energy density and safety concerns. Currently, developing efficient and safe hydrogen storage technologies is key to the large-scale utilization of hydrogen energy. To date, the most mature technologies are compressed hydrogen storage and liquid hydrogen storage, which require high pressure or continuous cryogenic conditions, making them difficult to meet the requirements for safe mobile use. Solid-state hydrogen storage, which tightly binds hydrogen to materials through physical or chemical adsorption, addresses safety issues while simultaneously achieving high thermodynamic and kinetic efficiency—a significant challenge.

[0003] To guide the development of hydrogen storage materials for automotive applications, the U.S. Department of Energy (DOE) has set a series of technical targets, including a capacity of 5.5 wt%, rapid hydrogen storage within 3–5 minutes, and 1500 cycles without degradation. However, known hydrogen storage materials do not meet the main performance requirements, particularly in terms of capacity, cycle stability, rate, and operating temperature. Hydrogen storage materials for automotive applications require several characteristics, including high capacity, near-ambient temperature operation, long cycle life, rapid absorption / desorption, and low cost. Combining these characteristics presents a challenge for existing materials. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide hydrogen storage materials, their preparation methods and applications. The hydrogen storage materials provided by the present invention have the characteristics of high capacity, near-ambient temperature operation, long cycle life, rapid absorption / desorption and low cost, and have excellent performance.

[0005] This invention provides a hydrogen storage material, the molecular formula of which is V. x Mo 1-x N; wherein x is greater than 0 and less than 1. Preferably, x is 0.1 to 0.5. More preferably, x is 0.1 to 0.3. Most preferably, the molecular formula of the hydrogen storage material is V. 0.2 Mo 0.8 N.

[0006] The hydrogen storage material of this invention is a dual transition metal nitride with a 10-15 layer structure. In some embodiments of this invention, the molecular formula of the hydrogen storage material is V0. 0.2 Mo 0.8 N has a 13-layer structure.

[0007] The interlayer spacing of the hydrogen storage material described in this invention is 7.0 Å to 7.5 Å. In some embodiments of this invention, the molecular formula of the hydrogen storage material is V. 0.2 Mo 0.8 N, with an interlayer spacing of 7.22 Å.

[0008] The present invention also provides a method for preparing any of the above-described hydrogen storage materials, comprising the following steps:

[0009] S1) V2O5, MoO3 and Na2MoO4•2H2O were ball-milled and mixed.

[0010] S2) Under a protective atmosphere containing NH3, the ball-milled mixture obtained in step S1) is calcined at 600℃~700℃ for 4 h~6 h;

[0011] S3) The calcined material obtained in step S2) is stirred in 0.05 mol / L~0.15 mol / L hydrochloric acid at a temperature of 70℃~90℃ for 2 h~4 h to obtain hydrogen storage material.

[0012] This invention first involves ball milling V₂O₅, MoO₃, and Na₂MoO₄•₂H₂O. Specifically, V₂O₅ and MoO₃ are first mixed, then the resulting V₂O₅ and MoO₃ mixture is mixed with Na₂MoO₄•₂H₂O to obtain a mixture of V₂O₅, MoO₃, and Na₂MoO₄•₂H₂O, which is then ball milled.

[0013] The atomic molar ratio of V in V₂O₅ to Mo in MoO₃ in this invention is (0~1):(1~0), and is neither 0:1 nor 1:0; the molar ratio of the mixture of V₂O₅ and MoO₃ to Na₂MoO₄•2H₂O is 1:1. The Na₂MoO₄•2H₂O in this invention serves to lower the preparation temperature and is removed during subsequent acid stirring.

[0014] The ball milling mixing method described in this invention specifically involves running the mixture at a speed of 300 rpm to 500 rpm for 15 to 30 minutes, repeated twice. In some embodiments of this invention, the ball milling mixing method specifically involves running the mixture at a speed of 400 rpm in both forward and reverse directions for 20 minutes each, for a total of two runs. The ball milling mixing method described in this invention is performed using a planetary ball mill.

[0015] In this invention, V₂O₅, MoO₃, and Na₂MoO₄•₂H₂O are ball-milled and then calcined at 600°C to 700°C for 4 to 6 hours under a protective atmosphere containing NH₃. Specifically, the ball-milled mixture obtained in step S1) is heated to 600°C to 700°C at a rate of 4°C / min to 6°C / min and calcined for 4 to 6 hours under a protective atmosphere containing NH₃. In some embodiments of this invention, the ball-milled mixture obtained in step S1) is heated to 650°C at a rate of 5°C / min and calcined for 5 hours under a protective atmosphere containing NH₃.

[0016] The NH3-containing protective atmosphere described in this invention is a mixture of NH3 and a protective gas, preferably a mixture of NH3 and Ar. The volume content of NH3 in the NH3-containing protective atmosphere described in this invention is 8% to 12%, preferably 10%.

[0017] In this invention, after calcining the ball-milled mixture, the resulting calcined material is stirred in 0.05 mol / L to 0.15 mol / L hydrochloric acid at a temperature of 70°C to 90°C for 2 to 4 hours to obtain a hydrogen storage material. Preferably, the resulting calcined material is stirred in 0.08 mol / L to 0.12 mol / L hydrochloric acid at a temperature of 75°C to 85°C for 2.5 to 3.5 hours. In some embodiments of this invention, the resulting calcined material is stirred in 0.1 mol / L hydrochloric acid at 80°C for 3 hours. The hydrochloric acid described in this invention can introduce defects into the material, which is beneficial for hydrogen storage.

[0018] This invention also provides the application of any of the above-described hydrogen storage materials as on-board solid-state hydrogen storage materials. The hydrogen storage material V provided by this invention... x Mo 1-x N, belonging to MXene materials, is a hydrogen storage material with high hydrogen storage capacity, fast hydrogen storage rate, and strong hydrogen storage stability. It exhibits significant advantages in the field of on-board solid-state hydrogen storage. Experiments show that the hydrogen storage material provided by this invention, with V... 0.2 Mo 0.8 Taking N as an example, it reversibly absorbs / releases 9.26 wt% hydrogen within minutes at 109.5 bar and 150°C. At a hydrogen pressure of 73.6 bar, it can absorb 5.6 wt% hydrogen within 30 seconds. More importantly, V... 0.2 Mo 0.8 Nitrogen materials exhibit excellent cycling stability, showing no capacity loss during 500 ultra-long cycles. Currently, no one has applied this material to solid-state hydrogen storage, making it outstanding in both material innovation and solid-state hydrogen storage performance. Attached Figure Description

[0019] Figure 1 V as described in this invention0.2 Mo 0.8 TEM image of N material;

[0020] Figure 2 V as described in this invention 0.2 Mo 0.8 High-angle annular dark-field scanning TEM image of N material;

[0021] Figure 3 V as described in this invention 0.2 Mo 0.8 XRD pattern of N material;

[0022] Figure 4 V as described in this invention 0.2 Mo 0.8 XAFS plot of N material;

[0023] Figure 5 V as described in this invention 0.2 Mo 0.8 Pressure-composition-temperature curves of N material at 150℃ and 109.5 bar hydrogen pressure;

[0024] Figure 6 V as described in this invention 0.2 Mo 0.8 Hydrogen storage rate curves of N material at 150℃ and 73.6 bar hydrogen pressure;

[0025] Figure 7 V as described in this invention 0.2 Mo 0.8 Figure of hydrogen absorption-desorption cycle test of N material at 150℃ and 39 bar hydrogen pressure;

[0026] Figure 8 V as described in this invention 0.2 Mo 0.8 Figure 1 shows hydrogen storage test data of N material at different temperatures under 41 bar.

[0027] Figure 9 The graph shows the hydrogen storage test data of the samples obtained in Examples 1-3 of this invention at 150°C and 41 bar. Detailed Implementation

[0028] This invention discloses hydrogen storage materials, their preparation methods, and applications. Those skilled in the art can refer to this document and appropriately modify the process parameters to achieve the desired results. It is particularly important to note that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The methods and applications of this invention have been described through preferred embodiments; those skilled in the art will clearly be able to modify or appropriately alter and combine the methods and applications described herein without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

[0029] The present invention will be further described below with reference to the embodiments:

[0030] Example 1

[0031] V was synthesized using the molten salt method 0.2 Mo 0.8 N, the specific process is as follows:

[0032] V₂O₅ and MoO₃ were mixed together at a V to Mo atomic molar ratio of 2:8 to obtain a V₂O₅ / MoO₃ mixture. Then, the obtained V₂O₅ / MoO₃ mixture was mixed with Na₂MoO₄•₂H₂O at a molar ratio of 1:1 to obtain a mixture of V₂O₅, MoO₃ and Na₂MoO₄•₂H₂O. The resulting mixture was then ball-milled in a planetary ball mill, first running forward at 400 rpm for 20 minutes, and then running in reverse at 400 rpm for 20 minutes.

[0033] One gram of the ball-milled mixture was placed in a ceramic boat and calcined at 650°C for 5 h in a 10% NH3 / Ar atmosphere at a heating rate of 5°C / min. The calcined product was placed in 0.1 mol / L hydrochloric acid, heated and stirred at 80°C for 3 h, filtered, washed, and dried. The sample was collected, and this sample is V. 0.2 Mo 0.8 N.

[0034] V was examined using transmission electron microscopy (TEM). 0.2 Mo 0.8 The microstructure of N was characterized. For example... Figure 1 and Figure 2 As shown, Figure 1 V as described in this invention 0.2 Mo 0.8 TEM image of N material, Figure 2 V as described in this invention 0.2 Mo 0.8 High-angle annular dark-field scanning TEM image of N material. Figure 1 It can be seen that V 0.2 Mo 0.8N exhibits a two-dimensional (2D) form, with a multi-layered structure of approximately 13 layers. (The remaining text appears to be incomplete and possibly contains errors.) Figure 2 Distinct dark spots were observed, which are V atoms. The low contrast compared to Mo in this mode confirms that V atoms were successfully alloyed into the MoN lattice.

[0035] V was examined using an X-ray diffractometer (XRD). 0.2 Mo 0.8 N was characterized. For example... Figure 3 As shown, Figure 3 V as described in this invention 0.2 Mo 0.8 XRD pattern of N material. (From...) Figure 3 As can be seen, the V described in this invention 0.2 Mo 0.8 The interlayer spacing of the N material is 7.22 Å.

[0036] X-ray absorption fine structure (XAFS) analysis of V 0.2 Mo 0.8 N was characterized, and the effect of V alloying on composition and electronic structure was determined. For example... Figure 4 As shown, Figure 4 V as described in this invention 0.2 Mo 0.8 XAFS plot of N material. (From...) Figure 4 It can be seen that V 0.2 Mo 0.8 The Mo K-edges of N are similar to those of MoN, indicating that the coordination environment around the Mo center is very similar. Compared to MoN, V 0.2 Mo 0.8 The absorption edge of N shifts negatively. Energy transfer confirms that the alloyed V atoms donate electrons to the Mo atoms, leading to a redistribution of charge within the 2D matrix.

[0037] Hydrogen storage performance was evaluated using a domestically produced Sieverts pressure-composition-temperature (PCT, USTBPCT-100, University of Science and Technology Beijing) instrument, including pressure-composition-temperature curve testing, hydrogen storage rate curve testing, and hydrogen absorption-desorption cycle testing. Before testing, the sample was evacuated at 150°C for one hour. The evaluation is as follows:

[0038] like Figure 5 As shown, Figure 5 V as described in this invention 0.2 Mo 0.8 Pressure-composition-temperature curves of N material at 150℃ and 109.5 bar hydrogen pressure. (From...) Figure 5 It can be seen that at 150℃ and a hydrogen pressure of 109.5 bar, V 0.2 Mo 0.8The hydrogen adsorption capacity of N material can reach 9.26 wt%.

[0039] like Figure 6 As shown, Figure 6 V as described in this invention 0.2 Mo 0.8 Hydrogen storage rate curves of N material at 150℃ and 73.6 bar hydrogen pressure. (Source: [Insert source here]) Figure 6 It can be seen that at 150℃ and a hydrogen pressure of 73.6 bar, V 0.2 Mo 0.8 The N material can absorb 5.6 wt% hydrogen gas within 30 seconds.

[0040] like Figure 7 As shown, Figure 7 V as described in this invention 0.2 Mo 0.8 Hydrogen absorption-desorption cycle test results of N material at 150℃ and 39 bar hydrogen pressure. (Source: [Insert source here]) Figure 7 It can be seen that at 150℃ and 39 bar hydrogen pressure, V 0.2 Mo 0.8 After 500 hydrogen absorption-desorption cycles, the hydrogen load of the N material did not decrease significantly, demonstrating excellent cycle stability, indicating that V 0.2 Mo 0.8 Nitrogen materials exhibit excellent cyclic reversibility, making them suitable for practical applications.

[0041] like Figure 8 As shown, Figure 8 V as described in this invention 0.2 Mo 0.8 Figure 1. Hydrogen storage test data of N material at different temperatures under 41 bar.

[0042] The hydrogen storage material V in the above study 0.2 Mo 0.8 Nitrogen (N) exhibits superior hydrogen storage performance, with a hydrogen storage capacity of up to 9.26 wt% at 109.5 bar, far exceeding most conventional hydrogen storage materials. Simultaneously, this material displays rapid hydrogen adsorption / desorption kinetics and excellent cycle reversibility. Surface functional groups enable the adsorption of hydrogen molecules, the presence of defects promotes heterogeneous hydrogen dissociation, and the heterometallic composition enables a rapid response to hydrogen, providing a new strategy for hydrogen capture and storage. This mechanism breaks through the limitations of traditional single hydrogen adsorption modes, and in the future, high-efficiency hydrogen storage materials can be developed through multi-scale design.

[0043] Example 2

[0044] Following the same preparation steps as in Example 1, only adjusting the amount of raw materials, V was prepared. 0.1 Mo 0.9 N sample.

[0045] Example 3

[0046] Following the same preparation steps as in Example 1, only adjusting the amount of raw materials, V was prepared. 0.3 Mo 0.7 N sample.

[0047] The samples obtained in Examples 2 and 3 were subjected to hydrogen storage tests at 150°C and 41 bar. The corresponding data from Example 1 are also listed therein. The results are as follows: Figure 9 As shown, Figure 9 The graph shows the hydrogen storage test data of the samples obtained in Examples 1-3 of this invention at 150°C and 41 bar.

[0048] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. Hydrogen storage material, characterized in that The molecular formula of the hydrogen storage material is V x Mo 1-x N; Wherein, the x is greater than 0 and less than 1.

2. The hydrogen storage material of claim 1, wherein, The x is 0.1~0.

5.

3. The hydrogen storage material of claim 2, wherein, The x is 0.1~0.

3.

4. The hydrogen storage material of claim 3, wherein, The molecular formula of the hydrogen storage material is V 0.2 Mo 0.8 N.

5. The hydrogen storage material of any one of claims 1 to 4, wherein, The hydrogen storage material is a double transition metal nitride with 10~15 layers structure.

6. The hydrogen storage material of claim 5, wherein, The interlayer distance of the hydrogen storage material is 7.0 Å~7.5 Å.

7. The method of producing a hydrogen storage material according to any one of claims 1 to 6, characterized by, The method comprises the following steps: S1) ball-milling V2O5, MoO3 and Na2MoO4•2H2O; S2) calcining the ball-milling mixture obtained in step S1) at 600℃~700℃ for 4 h~6 h under NH3-containing protective atmosphere; S3) stirring the calcined material obtained in step S2) in 0.05 mol / L~0.15 mol / L hydrochloric acid at 70℃~90℃ for 2 h~4 h to obtain the hydrogen storage material.

8. The method of claim 7, wherein the hydrogen storage material is prepared by a method comprising: In step S1), the ball-milling is specifically: running at a speed of 300 rpm~500 rpm for 15 min~30 min twice.

9. The method of claim 7, wherein the hydrogen storage material is prepared by a method comprising: In step S2), the volume content of NH3 in the NH3-containing protective atmosphere is 8%~12%.

10. Application of the hydrogen storage material in any of claims 1~6 as a solid-state hydrogen storage material for vehicle.

Images