Preparation method and application of composite hydrogen storage material based on NiV2S4 and magnesium hydride

Abstract

The application relates to a preparation method of a novel NiV2S4 and magnesium hydride composite hydrogen storage material and application thereof, the material takes magnesium hydride and NiV2S4 as main components, and belongs to the technical field of magnesium-based hydrogen storage materials. The hydrogen storage material is prepared by mixing magnesium hydride and NiV2S4 through a ball milling process. The preparation method comprises the following steps: firstly, uniformly dispersing nickel chloride hexahydrate, sodium orthovanadate and thiourea into water; then, transferring into a Teflon container and keeping at 150 DEG C-180 DEG C for 12-24 h, washing and drying to obtain NiV2S4. Finally, ball milling the NiV2S4 and magnesium hydride to obtain the magnesium hydride composite hydrogen storage material based on NiV2S4. The composite hydrogen storage material has excellent performance, compared with the ball-milled magnesium hydride, the initial hydrogen release temperature is reduced by 138 DEG C, the hydrogen release amount reaches 6.21 wt% at 350 DEG C in 5 min, the hydrogen absorption amount reaches 4.8 wt% at 150 DEG C in 20 min, and the capacity is greater than 90% after 60 cycles at 300 DEG C.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of solid-state hydrogen storage materials, and particularly relates to a magnesium-based composite hydrogen storage material based on NiV2S4 and magnesium hydride as well as a preparation method and application thereof. BACKGROUND

[0002] People are actively seeking clean and sustainable energy alternatives, and hydrogen energy has become the focus due to its high efficiency and environmental friendliness. Hydrogen combustion only produces water, so it has wide application prospects in transportation, industry, and power, etc.

[0003] Solid-state hydrogen storage technology is the key to realizing hydrogen energy applications, and magnesium hydride (MgH2) is considered an ideal hydrogen storage material due to its high hydrogen storage capacity. However, there are some technical obstacles in the practical use of magnesium hydride, such as slow reaction speed at normal temperature and pressure, and performance degradation during hydrogen absorption and desorption. In order to improve the performance of magnesium hydride, scientists are trying various strategies, including alloying, nanocrystallization, doping transition metals and their compounds, and using carbon-based materials as carriers. In particular, doping transition metals and their compounds has been proven to effectively improve the hydrogen storage performance of magnesium-based materials, which may be the key to driving the development of hydrogen energy technology.

[0004] In short, hydrogen energy is a promising solution to energy and environmental problems, and magnesium hydride has great potential as a hydrogen storage material, although it still needs technical breakthroughs to overcome existing challenges. Researchers are optimizing the performance of magnesium hydride through various methods in order to achieve its efficient and stable application in practice.

[0005] Based on this, the present application is developed. SUMMARY

[0006] The present application aims to address the shortcomings of magnesium hydride and provides a magnesium-based composite hydrogen storage material based on NiV2S4 and magnesium hydride, which is a double metal sulfide and magnesium hydride composite hydrogen storage material that can reduce the hydrogen desorption temperature of magnesium hydride, reduce the agglomeration and growth of magnesium hydride particles during the cycling process, and thus improve the cycling stability and hydrogen storage capacity retention of the material.

[0007] The present application also provides a preparation method and application of the above-mentioned magnesium-based composite hydrogen storage material based on NiV2S4 and magnesium hydride.

[0008] To achieve the above-mentioned application purposes, the present application adopts the following technical solutions:

[0009] A composite hydrogen storage material based on NiV2S4 and magnesium hydride is prepared by ball milling NiV2S4 and magnesium hydride; the NiV2S4 is directly prepared by a high-temperature hydrothermal method, and the NiV2S4 has a nano-flower-like particle accumulation structure.

[0010] The application provides a preparation method of the NiV2S4 and MgH2 composite hydrogen storage material, which comprises the following steps:

[0011] 1) uniformly dispersing nickel chloride hexahydrate, sodium orthovanadate and thiourea in water, and then maintaining at 150-180 °C for 12-24 h;

[0012] 2) reducing to room temperature, and obtaining NiV2S4 after washing and drying the reactants;

[0013] 3) ball-milling the NiV2S4 and MgH2 uniformly, and obtaining the composite hydrogen storage material.

[0014] Specifically, in step 1), the molar ratio of nickel chloride hexahydrate, sodium orthovanadate and thiourea can be 1:1.5-2.5:3.5-5.

[0015] Specifically, in step 2), the drying is performed at 45-60 °C under vacuum for 12-24 h.

[0016] Specifically, in step 3), the prepared double transition metal sulfide NiV2S4 and MgH2 can be ball-milled at a mass ratio of 0.05-0.1:0.95-0.9.

[0017] Further, in step 3), the ball-to-material ratio can be 30-50:1 during the ball-milling process, and the rotation speed can be 300-550 rpm / min. The ball-milling is preferably performed in a hydrogen environment. During the ball-milling process, the ball-milling time can be 3-6 h; in order to prevent the phenomenon of cold welding during the ball-milling process, the ball-milling machine is stopped for 5-15 min every 20-40 min of rotation. Preferably, the ball-milling machine is stopped for 10 min every 30 min of rotation.

[0018] The application further provides a NiV2S4 and MgH2 composite hydrogen storage material prepared by the above preparation method. In order to perform subsequent performance tests, the obtained NiV2S4-MgH2 composite hydrogen storage material can be stored in an argon-filled glove box.

[0019] The application further provides an application of the above NiV2S4 and MgH2 composite hydrogen storage material in hydrogen storage. The composite hydrogen storage material has a hydrogen release amount of 6.1 wt% at 290 °C for 10 min, a hydrogen absorption amount of 4.8 wt% at 150 °C for 20 min, and a capacity of greater than 90% after 60 cycles at 300 °C.

[0020] The application aims to provide a NiV2S4 and magnesium hydride composite hydrogen storage material and its preparation and application. The composite hydrogen storage material has good hydrogen storage performance and can be applied to the fields of catalysts, hydrogen storage materials and the like. Compared with the prior art, the application has the following advantages and beneficial effects:

[0021] 1) The raw materials used in the preparation process of the composite hydrogen storage material are commercially available and have a relatively low price. The preparation method provided by the application is relatively simple, easy to operate and has a short experimental period.

[0022] 2) The flower-shaped NiV2S4 synthesized by the application significantly improves the hydrogen storage performance of magnesium hydride. Analysis shows that the addition of 5wt% NiV2S4 catalyst has the best hydrogen absorption and desorption performance effect on MgH2. The dehydrogenation starting temperature of the MgH2-5NiV2S4 composite material is 227°C, and the hydrogen is basically completely released at 320°C, which is much lower than the desorption temperature of MgH2.

[0023] 3) With the addition of the NiV2S4 catalyst, the hydrogen absorption and desorption kinetics and the cycling performance of MgH2 are greatly improved. At 350°C, the hydrogen release amount reaches 6.21wt% in 5 minutes, at 150°C, the hydrogen absorption amount reaches 4.8wt% in 20 minutes, and after 60 cycles at 300°C, the capacity is greater than 90%. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is an XRD spectrum of NiV2S4 in Example 1 of the application;

[0025] Figure 2 It is an SEM picture of NiV2S4 in Example 1 of the application;

[0026] Figure 3 It is a TPD curve of commercial MgH2, ball-milled MgH2, MgH2-5NiV2S4, MgH2-8NiV2S4 and MgH2-10NiV2S4 composite materials in the application;

[0027] Figure 4 It is an isothermal dehydrogenation curve of MgH2-5NiV2S4 composite material and MgH2 at 350°C in Example 2 of the application;

[0028] Figure 5 It is an isothermal hydrogen absorption curve of MgH2-5NiV2S4 composite material and MgH2 at different temperatures in Example 2 of the application;

[0029] Figure 6 It is a cycling curve of MgH2-5NiV2S4 composite material at 300°C in Example 2 of the application. DETAILED DESCRIPTION

[0030] The technical solutions of the present application will be described in detail below through specific examples, but it is emphasized that the protection scope of the present application is not limited to the specific examples described below.

[0031] In the following examples, unless otherwise specifically stated, the raw materials used are ordinary commercially available products that can be directly purchased on the market, or can be prepared by conventional technical methods in the art.

[0032] The room temperature mentioned in the text refers to 25±5℃.

[0033] Example 1:

[0034] The preparation method of the NiV2S4 is as follows:

[0035] First, 5 mmol of nickel chloride hexahydrate, 10 mmol of sodium orthovanadate, and 20 mmol of thiourea were added to 80 mL of deionized water (molar ratio of 1:2:4), and ultrasonic dispersion was performed for 30 min. Then the solution was transferred to a stainless steel autoclave with a Teflon lining, and kept at 170℃ for 18 h. After the reaction was completed, it was naturally cooled to room temperature, and the reaction was washed with deionized water and ethanol respectively for 3 times at room temperature, and then dried in a vacuum drying oven at 60℃ for 12 h under vacuum condition, to obtain the catalyst NiV2S4.

[0036] Example 2:

[0037] The prepared NiV2S4 was ball milled with MgH2 powder at a mass ratio of 0.05:0.95 for 4 h, and the vacuum ball milling tank was kept in a hydrogen atmosphere, the ball-to-material ratio was 40:1, the rotation speed was 400 rpm / min, and the ball mill was stopped for 10 min every 30 min. Ball milling was uniformly mixed to obtain MgH2-5 NiV2S4 composite hydrogen storage material.

[0038] In order to test the subsequent performance, the prepared MgH2-5 NiV2S4 composite hydrogen storage material was stored in an argon-filled glove box.

[0039] Example 3:

[0040] The prepared NiV2S4 was ball milled with MgH2 powder at a mass ratio of 0.08:0.92 for 4 h, and the vacuum ball milling tank was kept in a hydrogen atmosphere, the ball-to-material ratio was 40:1, the rotation speed was 400 rpm / min, and the ball mill was stopped for 10 min every 30 min. Ball milling was uniformly mixed to obtain MgH2-8 NiV2S4 composite hydrogen storage material.

[0041] For subsequent performance test, the obtained MgH2-8 NiV2S4 composite hydrogen storage material is stored in a glove box filled with argon atmosphere.

[0042] Example 4:

[0043] The prepared NiV2S4 is ball milled with MgH2 powder at a mass ratio of 0.1:0.9 for 4 h, a hydrogen atmosphere is maintained in a vacuum ball milling tank, a ball-to-material ratio is 40:1, a rotation speed is 400 rpm / min, and the ball mill is stopped for 10 min every 30 min of rotation. Ball milling is uniformly obtained to obtain a MgH2-10 NiV2S4 composite hydrogen storage material.

[0044] For subsequent performance test, the obtained MgH2-10 NiV2S4 composite hydrogen storage material is stored in a glove box filled with argon atmosphere.

[0045] Example 5:

[0046] The preparation method of the NiV2S4, and the specific implementation steps are as follows:

[0047] First, 5 mmol of nickel chloride hexahydrate, 12 mmol of sodium orthovanadate and 25 mmol of thiourea are added to 60 mL of deionized water (molar ratio of 1:2.4:5), and ultrasonic dispersion is performed for 30 min. Then, the solution is transferred to a stainless steel autoclave containing a Teflon lining, and is kept at 170℃ for 20 h. After the reaction is completed, natural cooling is performed to room temperature, the reaction is centrifugally washed with deionized water and ethanol respectively for 3 times at room temperature, and then vacuum drying is performed in a vacuum drying box at 50℃ for 12 h, to obtain the catalyst NiV2S4.

[0048] Performance determination

[0049] First, the double transition metal sulfide NiV2S4 synthesized in Example 1 is characterized by XRD and SEM. Figure 1 、 2 The XRD spectrum and the SEM image of the NiV2S4 in Example 1 of the present application are respectively given. Figure 1 and Figure 2 The results show that the flower-shaped NiV2S4 catalyst is successfully prepared, which is a structure of nano flower-shaped particles accumulated, and the particle size is 500-800 nm.

[0050] In order to explore the influence of the addition of NiV2S4 on magnesium hydride, isothermal programmed desorption experiments (TPD) are performed on MgH2 and three kinds of composite hydrogen storage materials with different proportions in Examples 2, 3 and 4, the TPD temperature rising rate is 2℃ / min, and the results are shown in Figure 3 . From Figure 3It can be seen that the initial dehydrogenation temperature of ball-milled MgH2 is 365℃, while the initial dehydrogenation temperature of the MgH2-5 NiV2S4 composite hydrogen storage material is 227℃. The addition of the NiV2S4 catalyst reduced the initial dehydrogenation temperature of MgH2 by 138℃. According to... Figure 3 As shown, adding 5 wt.% NiV2S4 yields the best results.

[0051] To investigate the effect of NiV2S4 addition on the hydrogen absorption and desorption performance of magnesium hydride, isothermal dehydrogenation and hydrogen absorption performance experiments were conducted on MgH2-5NiV2S4 composite hydrogen storage material (with 5 wt.% addition). The results are shown in [Figure number missing]. Figure 4 and Figure 5 .

[0052] Figure 4 The isothermal dehydrogenation curves of the MgH2-5NiV2S4 composite hydrogen storage material and MgH2 at 350℃ in Example 2 of this invention are presented. Figure 4 It can be seen that the MgH2-5NiV2S4 composite hydrogen storage material can release 6.21 wt.% hydrogen in 5 min at 350℃, and the dehydrogenation is basically completed within 5 min. In contrast, MgH2 can only dehydrogenate 1.5 wt.% hydrogen in 30 min at the same temperature. The results show that the doping of NiV2S4 significantly improves the dehydrogenation performance of MgH2.

[0053] Figure 5 Isothermal hydrogen absorption curves of the MgH2-5NiV2S4 composite hydrogen storage material and MgH2 at different temperatures are presented in Example 2 of this invention. Figure 5 It can be seen that at 150℃, the hydrogen absorption capacity of the MgH2-5 NiV2S4 composite hydrogen storage material reaches 4.5 wt.% within 10 min and 4.8 wt% within 20 min. However, MgH2 needs to be at a high temperature of 350℃ to absorb 4.5 wt% of hydrogen. The results show that the addition of NiV2S4 can greatly improve the hydrogen absorption kinetics of the composite material at low temperature.

[0054] Figure 6 The isothermal cycling curves of the MgH2-5NiV2S4 composite material in Example 2 of this invention at 300℃ are given. Figure 6 As shown, the amount of hydrogen dehydrogenation in the first cycle was 5.98 wt.%, while the amount of hydrogen dehydrogenation in the 60th cycle was 5.47 wt.%, and the hydrogen dehydrogenation capacity retention rate was 91.47%, indicating that the MgH2-5 NiV2S4 composite hydrogen storage material has good cycle stability.

[0055] In summary, the hydrogen storage material provided by the present application exhibits excellent performance, which has a very important influence on promoting the progress and practical application of magnesium-based hydrogen storage technology. Through optimization and improvement, the present application not only improves the hydrogen storage efficiency, but also enhances the cycle stability of the material, which are key factors to realize the commercialization of hydrogen energy technology. Therefore, the present application has potential great value in promoting clean energy transformation and solving energy crisis.

[0056] Although the above embodiments demonstrate a recommended implementation of the present application, this does not limit the scope of protection of the present application. Any minor adjustment, innovation or alternative within the framework of the present application, as long as the changes do not deviate from the core concept and technical solution of the present application, should be considered as part of the protection of the present application.

Claims

1. A hydrogen storage material based on NiV2S4 and magnesium hydride composite, characterized in that, The material is prepared by ball milling NiV2S4 and magnesium hydride; the NiV2S4 is prepared by hydrothermal method, and the NiV2S4 has a structure of stacked nano-flower-like particles; the specific preparation method of the NiV2S4 and magnesium hydride composite hydrogen storage material is as follows: 1) Disperse nickel chloride hexahydrate, sodium orthovanadate and thiourea in water, and then keep at 150℃-180℃ for 12-24 h; 2) After cooling to room temperature, washing and drying, NiV2S4 is obtained; 3) Mix NiV2S4 and magnesium hydride by ball milling to obtain the final product.

2. The preparation method of the NiV2S4 and magnesium hydride composite hydrogen storage material according to claim 1, characterized in that, Includes the following steps: 1) Disperse nickel chloride hexahydrate, sodium orthovanadate and thiourea in water, and then keep at 150℃-180℃ for 12-24 h; 2) After cooling to room temperature, washing and drying, NiV2S4 is obtained; 3) Mix NiV2S4 and magnesium hydride by ball milling to obtain the final product.

3. The preparation method of the NiV2S4 and magnesium hydride composite hydrogen storage material as described in claim 2, characterized in that, In step 1), the molar ratio of nickel chloride hexahydrate, sodium orthovanadate, and thiourea is 1:1.5-2.5:3.5-5.

4. The preparation method of the NiV2S4 and magnesium hydride composite hydrogen storage material as described in claim 2, characterized in that, In step 2), dry under vacuum conditions at 45 °C-60 °C for 12-24 h.

5. The preparation method of the NiV2S4 and magnesium hydride composite hydrogen storage material as described in claim 2, characterized in that, In step 3), the prepared NiV2S4 and magnesium hydride are ball-milled at a mass ratio of 0.05-0.1:0.95-0.

9.

6. The preparation method of the NiV2S4 and magnesium hydride composite hydrogen storage material as described in claim 5, characterized in that, In step 3), during the ball milling process, the ball-to-material ratio is 30-50:1; the rotation speed is 300-550 rpm / min.

7. The preparation method of the NiV2S4 and magnesium hydride composite hydrogen storage material as described in claim 5, characterized in that, In step 3), ball milling is performed in a hydrogen atmosphere.

8. The preparation method of the NiV2S4 and magnesium hydride composite hydrogen storage material as described in claim 5, characterized in that, In step 3), the ball milling time is 3-6 hours; during the ball milling process, the ball mill is stopped for 5-15 minutes every 20-40 minutes of rotation.

9. The application of the NiV2S4 and magnesium hydride composite hydrogen storage material as described in claim 1 in hydrogen storage.

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