Neutron diffraction testing device and method for hydrogen storage material in liquid hydrogen environment

Abstract

The invention relates to a neutron diffraction testing device and method for a hydrogen storage material in a liquid hydrogen environment, in particular to the technical field of hydrogen storage material testing, and the neutron diffraction testing device comprises a neutron diffraction testing unit and a liquid hydrogen environment providing unit arranged between radial collimators of the neutron diffraction testing unit; the liquid hydrogen environment providing unit comprises a hydrogen end, a liquid helium end, a liquid hydrogen environment end and a gas recovery end; the hydrogen end is connected with the liquid hydrogen environment end through the heat exchanger; the liquid helium end is connected with a cold medium channel of the heat exchanger; and a hydrogen outlet of the liquid hydrogen environment end is connected with the gas recovery end. According to the neutron diffraction testing device for the hydrogen storage material in the liquid hydrogen environment, provided by the invention, the liquid hydrogen environment unit is introduced into the testing device, so that neutron diffraction testing of the hydrogen storage material in the dynamic hydrogen absorption / desorption or service process in the liquid hydrogen environment is realized, and crystal structure evolution information and related information such as material stress and strain are obtained; therefore, the performance characterization accuracy of the hydrogen storage material is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the hydrogen storage material testing technical field, specifically relates to a kind of hydrogen storage material's neutron diffraction testing device and method under liquid hydrogen environment. BACKGROUND

[0002] Hydrogen storage material refers to the hydrogen storage material that hydrogen can be stored in larger amount per unit volume by forming metal reversible storage and release of hydrogen gas through metal hydride or porous non-metallic material.The specific purpose of this hydrogen storage technology is to store useful amount of hydrogen so that hydrogen-consuming devices can operate for a long enough time without constantly replenishing their hydrogen fuel reserves.Adsorbing hydrogen to form hydride compounds is usually an exothermic reaction, which usually requires removal and dissipation of at least part of the generated heat so as not to inhibit further hydrogen adsorption.On the contrary, desorbing hydrogen from hydride compounds is usually an endothermic reaction, which may require rapid and / or continuous heating to drive the reaction and release hydrogen at a sufficient rate.

[0003] Therefore, analyzing the related microstructure of hydrogen storage material can have a more in-depth understanding of the hydrogen storage principle and hydrogen storage performance of hydrogen storage material, and thus the optimization of hydrogen storage material can be realized.

[0004] Current microanalysis of hydrogen storage material is mainly carried out by neutron diffraction test, such as studying the cell parameters, site and occupation number of absorbed deuterium atoms and other performance results of hydrogen storage material. For example, the prior art (Chen Bo, Fan Zhijian, Sun Guang'ai, et al. Neutron diffraction experimental study on microstructure of hydrogen storage materials and magnetic materials [C] / / Abstracts of the Fourth National Congress of the Chinese Crystallographic Society and Academic Conference. 2008.) discloses that neutron powder diffraction technology is applied to carry out experimental study on microstructure and deuterium occupation of La-Ni-Al-D sample material of deuterium-absorbed lanthanum-based alloy, and cell parameters and micro-distribution of deuterium of different deuterium-absorbed phases are obtained.

[0005] However, the current neutron diffraction test of hydrogen storage material is carried out in the form of neutron diffraction powder, specifically, the powder sample is subjected to hydrogen absorption / desorption and then subjected to neutron diffraction analysis. This detection method has certain defects, and it is not conducive to the analysis of performance parameters in the hydrogen storage process because it cannot realize dynamic research on the related performance of hydrogen storage material under dynamic hydrogen absorption / desorption. SUMMARY

[0006] In view of the problems existing in the prior art, the purpose of the present application is to provide a neutron diffraction testing device and method for hydrogen storage material under liquid hydrogen environment, so as to realize dynamic neutron diffraction analysis of hydrogen storage material under liquid hydrogen environment, thereby realizing efficient optimization of hydrogen storage performance of hydrogen storage material.

[0007] To achieve this purpose, the present application adopts the following technical solutions:

[0008] In a first aspect, the present application provides a neutron diffraction testing device for hydrogen storage materials in a liquid hydrogen environment, comprising:

[0009] a neutron diffraction testing unit, and a liquid hydrogen environment providing unit arranged between radial collimators of the neutron diffraction testing unit;

[0010] The liquid hydrogen environment providing unit comprises a hydrogen gas end, a liquid helium end, a liquid hydrogen environment end, and a gas recovery end.

[0011] The hydrogen gas end is connected to the liquid hydrogen environment end through a heat exchanger.

[0012] The liquid helium end is connected to a cold medium channel of the heat exchanger.

[0013] The hydrogen gas outlet of the liquid hydrogen environment end is connected to the gas recovery end.

[0014] The neutron diffraction testing device for hydrogen storage materials in a liquid hydrogen environment provided by the present application realizes neutron diffraction testing of hydrogen storage materials during dynamic hydrogen absorption / release in a liquid hydrogen environment by introducing a liquid hydrogen environment unit into the testing device, so as to obtain crystal structure evolution information and related material stress and strain information, thereby improving the accuracy of performance characterization of hydrogen storage materials.

[0015] As a preferred technical solution of the present application, a first pressure reducing valve, a pressure detection device, a first switch valve, and a first regulating valve are sequentially arranged on a pipeline connecting the hydrogen gas end and the heat exchanger.

[0016] Preferably, the first regulating valve is adjacent to the heat exchanger.

[0017] As a preferred technical solution of the present application, a first branch is arranged between the first pressure reducing valve and the pressure detection device.

[0018] Preferably, the first branch is connected to the gas recovery end, and a second pressure reducing valve is arranged on the first branch.

[0019] As a preferred technical solution of the present application, a second branch is arranged between the first regulating valve and the heat exchanger.

[0020] Preferably, the second branch is connected to the gas recovery end.

[0021] As a preferred technical solution of the present application, a second switch valve and a vacuum pump are sequentially arranged on the second branch.

[0022] As a preferred technical solution of the present application, a third switch valve and a third pressure reducing valve are sequentially arranged on a pipeline between the liquid helium end and the heat exchanger.

[0023] As a preferred technical scheme of the present application, the liquid helium end is provided with a pressure detection device and a temperature detection device.

[0024] Preferably, the outlet of the cold medium channel of the heat exchanger is connected with the gas recovery end.

[0025] As a preferred technical scheme of the present application, the fourth switch valve and the second regulating valve are sequentially arranged on the pipeline between the liquid hydrogen environment end and the gas recovery end.

[0026] Preferably, the liquid hydrogen environment providing unit is provided with a safety purge gas end.

[0027] In the second aspect, the present application provides a neutron diffraction testing method for hydrogen storage materials in a liquid hydrogen environment, and the neutron diffraction testing method comprises the following steps:

[0028] The hydrogen gas end and the liquid helium end are connected through the heat exchanger, and the hydrogen gas is liquefied by using the liquid helium to obtain liquid hydrogen;

[0029] The liquid hydrogen enters the liquid hydrogen environment end to form a liquid hydrogen environment, and the hydrogen storage material is placed in the liquid hydrogen environment for neutron diffraction testing.

[0030] As a preferred technical scheme of the present application, the hydrogen storage material comprises a hydrogen storage functional material or a hydrogen storage structural material.

[0031] Preferably, the temperature of the liquid hydrogen environment is 15-25K.

[0032] Preferably, the hydrogen gas used in the liquid hydrogen environment comprises deuterium gas.

[0033] Preferably, the diffraction angle of the neutron diffraction testing is 45-180°.

[0034] Preferably, the neutron diffraction testing comprises the following steps: the hydrogen storage material is placed in the liquid hydrogen or liquid deuterium environment, the neutron diffraction spectrum at different time points is collected one by one along with the standing time, and the evolution of the crystal material structure in the hydrogen storage material is analyzed.

[0035] Compared with the prior art, the present application has the following beneficial effects:

[0036] The neutron diffraction testing device provided by the present application can realize the following effects: the sample is in contact with the liquid hydrogen part, the crystal structure difference of the sample at different heights close to the liquid hydrogen liquid surface, the information of the specific crystal structure phase, stress and strain distribution, dislocation density, etc. can be obtained. The above testing method can be used for the structural phase change characterization of the hydrogen-containing structure material at low temperature, and can also be used for the characterization of the hydrogen charging and discharging process of the related hydrogen storage material under the condition. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1is a schematic diagram of a neutron diffraction testing device provided by an embodiment of the present application;

[0038] Figure 2 is a schematic diagram of a liquid hydrogen environment providing unit in an embodiment of the present application;

[0039] Figure 3 is a neutron diffraction spectrum of a ZrCo alloy sample before and after deuterium storage in Embodiment 1 of the present application;

[0040] Figure 4 is a neutron diffraction spectrum of an Al-Mg containing alloy sample during deuterium storage in Embodiment 1 of the present application.

[0041] In the figure: 110 - diffraction detector, 120 - radial collimator, 130 - neutron beam, 140 - diaphragm, 200 - liquid hydrogen environment providing unit, 210 - hydrogen gas end, 211 - first branch, 212 - second branch, 220 - liquid helium end, 230 - heat exchanger, 240 - liquid hydrogen environment end, 250 - gas recovery end, 260 - safety purge gas end.

[0042] The present application is further described below. However, the following examples are merely simple examples of the present application and do not represent or limit the scope of protection of the present application, which is defined by the claims. DETAILED DESCRIPTION

[0043] To better illustrate the present application and facilitate understanding of the technical solutions of the present application, the typical but non-limiting embodiments of the present application are as follows:

[0044] The current neutron diffraction test of hydrogen storage materials is in the form of neutron diffraction powder, which is used to study hydrogen storage materials. Specifically, the powder sample is subjected to hydrogen absorption / desorption and then subjected to neutron diffraction analysis. This detection method has certain defects. This detection method cannot realize dynamic research on the related performance of hydrogen storage materials under dynamic hydrogen absorption / desorption, which is not conducive to the analysis of performance parameters during hydrogen storage. Based on this, the present application introduces a liquid hydrogen environment providing unit into the neutron diffraction testing device to realize the research on the hydrogen storage performance of hydrogen storage materials under dynamic hydrogen absorption / desorption, as follows:

[0045] First, this embodiment provides a neutron diffraction testing device for hydrogen storage materials in a liquid hydrogen environment, as shown in Figure 1 The neutron diffraction testing device comprises:

[0046] a neutron diffraction testing unit, and a liquid hydrogen environment providing unit 200 arranged between the radial collimator 120 of the neutron diffraction testing unit, as shown in Figure 2

[0047] ​The liquid hydrogen environment providing unit 200 comprises a hydrogen end 210, a liquid helium end 220, a liquid hydrogen environment end 240 and a gas recovery end 250.

[0048] The hydrogen end 210 is connected with the liquid hydrogen environment end 240 through a heat exchanger 230.

[0049] The liquid helium end 220 is connected with a cold medium channel of the heat exchanger 230.

[0050] The hydrogen outlet of the liquid hydrogen environment end 240 is connected with the gas recovery end 250.

[0051] In the present application, the neutron diffraction testing unit is a neutron diffraction device commonly used in the art, which comprises components such as a diffraction detector 110, a radial collimator 120, a neutron beam 130 and a diaphragm 140, and can be obtained or designed according to the prior art and purchased.

[0052] In the present application, the hydrogen storage material refers to a hydrogen storage structural material or a hydrogen storage functional material.

[0053] In the present application, the hydrogen end 210 can be realized by using a hydrogen storage device such as a gas cylinder.

[0054] In the present application, in order to realize effective liquefaction of hydrogen, the liquid helium end 220 can select a liquid helium Dewar as an ultralow-temperature cold source. High-pressure hydrogen gas is first reduced to a set pressure by a pressure reducing valve, then introduced into the heat exchanger 230 through a switch valve and a regulating valve group in sequence, and exchanges heat with 4.5K liquid helium therein. The low-temperature environment provided by the liquid helium cools the hydrogen gas to about 20K, and finally realizes the liquefaction of the hydrogen gas. The liquefied liquid hydrogen is introduced into the liquid hydrogen environment end 240 for neutron diffraction analysis.

[0055] In the present application, the liquid hydrogen environment end 240 can be realized by using a device such as a gas cylinder. During the process, the liquid hydrogen environment end 240 is affected by the experimental heat load, and the liquid hydrogen will gradually vaporize. The vaporized hydrogen gas is collected to the gas recovery end 250 through a reflux system to improve the gas utilization rate and economy of the system. The liquid helium used in the liquefaction process is converted into a gaseous state after absorbing heat, and is discharged to a hydrogen discharge pipeline through an exhaust channel to realize system heat balance.

[0056] In the present application, the gas recovery end 250 can be realized by using a gas cylinder, a gas storage device or the like.

[0057] In the application, to ensure the safety during the operation of the system, safety valves and bursting discs are installed on the hydrogen cylinder group and the top of the recovery tank, so that excess hydrogen can be quickly released to the exhaust system when the system pressure is too high. The end of the exhaust pipe is provided with a flame arrester and a check valve to prevent secondary disasters caused by external flame backflow and hydrogen backflow. At the same time, to avoid the formation of a flammable atmosphere inside the exhaust pipe, the system continuously introduces high-purity nitrogen into the exhaust pipe to maintain its inert (anaerobic) environment, further improving the safety redundancy of the exhaust process.

[0058] In the application, to ensure that the above sample liquid hydrogen environment is applicable to the experimental characterization of the neutron spectrometer, the related liquid hydrogen sample environment is designed to be miniaturized, and a multi-layer tank structure design can be selected, which adopts an aluminum alloy inner and outer shell and a related He gas-filled intermediate adiabatic layer, and experimental isotopes deuterium gas is used to replace traditional hydrogen as the hydrogen source, so that during the neutron experimental characterization process, the neutron beam can smoothly penetrate the sample environment device, irradiate the sample in the device, and realize in-situ neutron diffraction characterization.

[0059] In the application, to ensure experimental safety, the pipes of the related gas are designed with a recovery gas tank to avoid excessive pipe pressure causing valve leakage, and the corresponding valves are designed with a pressure sensing test device to specifically monitor the pressure value range.

[0060] In the application, during the in-situ neutron diffraction characterization experiment, the sample can be designed as a cylindrical sample, and a fixed groove and a clamp are arranged in the liquid hydrogen tank to enable the cylindrical sample to stand vertically in the internal space of the liquid hydrogen tank.

[0061] In the application, when performing neutron diffraction testing, the neutron beam spot size is controlled to be 5mm*5mm, and the sample can be scanned from top to bottom by neutron diffraction.

[0062] In the application, by controlling the liquid hydrogen injection amount, the height of the liquid hydrogen immersed cylindrical sample can be controlled, so that the sample at different heights in contact with the liquid hydrogen part and close to the liquid hydrogen liquid surface can realize the difference in crystal structure, and information such as specific crystal structure phase, stress and strain distribution, and dislocation density can be obtained.

[0063] The pipeline connected between the hydrogen end 210 and the heat exchanger 230 is sequentially provided with a first pressure reducing valve, a pressure detection device, a first switch valve and a first regulating valve.

[0064] The first regulating valve is adjacent to the heat exchanger 230.

[0065] A first branch 211 is arranged between the first pressure reducing valve and the pressure detection device.

[0066] The first branch 211 is connected with the gas recovery end 250, and a second pressure reducing valve is arranged on the first branch 211.

[0067] The second branch 212 is arranged between the first adjusting valve and the heat exchanger 230.

[0068] The second branch 212 is connected with the gas recovery end 250.

[0069] The second branch 212 is sequentially provided with a second switch valve and a vacuum pump.

[0070] The pipeline between the liquid helium end 220 and the heat exchanger 230 is sequentially provided with a third switch valve and a third pressure reducing valve.

[0071] The liquid helium end 220 is provided with a pressure detection device and a temperature detection device.

[0072] The outlet of the cold medium channel of the heat exchanger 230 is connected with the gas recovery end 250.

[0073] The pipeline between the liquid hydrogen environment end 240 and the gas recovery end 250 is sequentially provided with a fourth switch valve and a second adjusting valve.

[0074] In the application, the gas recovery end 250 is provided with a pressure relief exhaust pressure reducing valve, a pressure detection device and the like.

[0075] The liquid hydrogen environment providing unit 200 is provided with a safety purge gas end 260.

[0076] In the application, the safety purge gas end 260 is provided with a switch valve and a pressure reducing valve and the like valve assembly, so as to dilute the gas in the gas circuit, so as to ensure safety, and also to purge the liquid hydrogen environment providing unit 200 to ensure the stability of the liquid hydrogen environment providing unit 200.

[0077] In the application, the switch valve can be selected from a manual switch valve, an electric switch valve and the like, and specifically, an electromagnetic valve, a gas valve and the like are selected.

[0078] Secondly, the embodiment provides a neutron diffraction test method of hydrogen storage material in a liquid hydrogen environment, and specifically as follows: hydrogen gas is liquefied to obtain liquid hydrogen by using liquid helium through the heat exchanger 230 connecting the hydrogen gas end 210 and the liquid helium end 220.

[0079] The liquid hydrogen enters the liquid hydrogen environment end 240 to form a liquid hydrogen environment, and the hydrogen storage material is placed in the liquid hydrogen environment for neutron diffraction test.

[0080] The hydrogen storage material includes a hydrogen storage functional material or a hydrogen storage structural material.

[0081] The temperature of the liquid hydrogen environment is 15-25K, for example, it can be 15K, 16K, 17K, 18K, 19K, 20K, 21K, 22K, 23K, 24K or 25K, but is not limited to the listed values. Other values ​​not listed within this range also meet the requirements.

[0082] Wherein, the hydrogen used in the liquid hydrogen environment includes: deuterium gas.

[0083] The diffraction angle of the neutron diffraction test is 45-180°, for example, 45°, 90°, 135° or 180°, but is not limited to the listed values. Other values ​​not listed within the range also meet the requirements.

[0084] In the present invention, the neutron diffraction test characterization and analysis process involves controlling the size of the neutron beam spot, guiding the neutron beam to the front end of the sample device through an aperture and a neutron flight tube, receiving the neutron signal scattered by the sample by a neutron detector, a signal data acquisition system, a neutron experiment control system, and a neutron data processing system.

[0085] In this invention, during neutron diffraction testing, deuterium (D) is used to avoid interference from hydrogen (H), which produces strong incoherent neutron scattering, resulting in high background noise and severe attenuation of the Bragg peak intensity. Furthermore, to prevent the device material from contributing to non-target sample diffraction peaks (spurious peaks) in the experimental results, the neutron window of the experimental device is made of a titanium-zirconium alloy material that is transparent to the neutron beam.

[0086] 3. In order to illustrate the test results that can be achieved by the neutron diffraction test device for hydrogen storage materials in a liquid hydrogen environment provided by the present invention, the following actual examples are used for illustration, as follows:

[0087] Example 1

[0088] This embodiment provides a neutron diffraction testing device for hydrogen storage materials in a liquid hydrogen environment, specifically as follows:

[0089] A neutron diffraction test unit, and a liquid hydrogen environment providing unit 200 disposed between the radial collimator 120 of the neutron diffraction test unit;

[0090] The liquid hydrogen environment providing unit 200 includes: a hydrogen end 210, a liquid helium end 220, a liquid hydrogen environment end 240 and a gas recovery end 250;

[0091] The hydrogen end 210 is connected to the liquid hydrogen environment end 240 through a heat exchanger 230;

[0092] The liquid helium end 220 is connected to the cold medium channel of the heat exchanger 230;

[0093] The hydrogen outlet of the liquid hydrogen environment end 240 is connected with the gas recovery end 250.

[0094] The pipeline connecting the hydrogen end 210 and the heat exchanger 230 is sequentially provided with a first pressure reducing valve, a pressure detection device, a first switch valve and a first regulating valve.

[0095] The first regulating valve is adjacent to the heat exchanger 230.

[0096] A first branch 211 is arranged between the first pressure reducing valve and the pressure detection device.

[0097] The first branch 211 is connected with the gas recovery end 250 through a second pressure reducing valve.

[0098] A second branch 212 is arranged between the first regulating valve and the heat exchanger 230.

[0099] The second branch 212 is connected with the gas recovery end 250.

[0100] The second branch 212 is sequentially provided with a second switch valve and a vacuum pump.

[0101] A third switch valve and a third pressure reducing valve are sequentially arranged on the pipeline between the liquid helium end 220 and the heat exchanger 230.

[0102] The liquid helium end 220 is provided with a pressure detection device and a temperature detection device.

[0103] The outlet of the cold medium passage of the heat exchanger 230 is connected with the gas recovery end 250.

[0104] A fourth switch valve and a second regulating valve are sequentially arranged on the pipeline between the liquid hydrogen environment end 240 and the gas recovery end 250.

[0105] The liquid hydrogen environment providing unit 200 is provided with a safety purge gas end 260.

[0106] Application Example 1

[0107] The hydrogen storage material is tested by using the neutron diffraction testing device of Example 1, and the specific process is as follows:

[0108] The hydrogen gas end 210 and the liquid helium end 220 are connected through the heat exchanger 230, and the hydrogen gas is liquefied by using liquid helium to obtain liquid hydrogen;

[0109] The liquid hydrogen enters the liquid hydrogen environment end 240 to form a liquid hydrogen environment, and the hydrogen storage material is placed in the liquid hydrogen environment for neutron diffraction testing.

[0110] The temperature of the liquid hydrogen environment is 15-25K.

[0111] The hydrogen gas used in the liquid hydrogen environment comprises deuterium.

[0112] The diffraction angles of the neutron diffraction test are 45 degrees and 90 degrees.

[0113] The hydrogen storage material tested specifically is a ZrCo alloy sample and an aluminum-magnesium alloy sample, and the relevant low-temperature deuterium storage test results are as follows Figure 3 and Figure 4 , Figure 3 The neutron diffraction spectrum comparison of the ZrCo alloy sample before and after deuterium storage is as follows Figure 4 The neutron diffraction spectrum evolution of the aluminum-magnesium alloy sample during deuterium storage is as follows, and the evolution of the crystal material structure in the hydrogen storage material can be analyzed by analyzing the spectrum.

[0114] As can be seen from the above, the neutron diffraction test device for hydrogen storage materials in a liquid hydrogen environment provided by the application realizes neutron diffraction test of hydrogen storage materials during dynamic hydrogen absorption / release in a liquid hydrogen environment by introducing a liquid hydrogen environment unit into the test device, so as to obtain crystal structure evolution information and related material stress and strain information, thereby improving the accuracy of performance characterization of hydrogen storage materials.

[0115] The above describes the preferred embodiments of the application, but the application is not limited to the specific details in the above-described embodiments, and various simple modifications can be made to the technical solutions of the application within the technical concept of the application, and these simple modifications all belong to the protection scope of the application.

[0116] In addition, it should be noted that each specific technical feature described in the above-described specific embodiments can be combined in any appropriate manner without contradiction, and in order to avoid unnecessary repetition, the application will not further describe various possible combination manners.

[0117] In addition, various different embodiments of the application can also be combined in any manner, as long as they do not deviate from the technical concept of the application, and they should also be considered as disclosed by the application.

Claims

1. A neutron diffraction testing device for hydrogen storage materials in a liquid hydrogen environment, characterized in that: The neutron diffraction testing device comprises: a neutron diffraction testing unit, and a liquid hydrogen environment providing unit disposed between radial collimators of the neutron diffraction testing unit; The liquid hydrogen environment providing unit includes: a hydrogen end, a liquid helium end, a liquid hydrogen environment end and a gas recovery end; The hydrogen end is connected to the liquid hydrogen environment end through a heat exchanger; The liquid helium end is connected to the cold medium channel of the heat exchanger; The hydrogen outlet of the liquid hydrogen environment end is connected to the gas recovery end.

2. The neutron diffraction testing device according to claim 1, characterized in that: The pipeline connecting the hydrogen end and the heat exchanger is provided with a first pressure reducing valve, a pressure detection device, a first switch valve and a first regulating valve in sequence; Preferably, the first regulating valve is adjacent to the heat exchanger.

3. The neutron diffraction testing device according to claim 1 or 2, characterized in that: A first branch is provided between the first pressure reducing valve and the pressure detection device; Preferably, the first branch is connected to the gas recovery end, and a second pressure reducing valve is provided on the first branch.

4. The neutron diffraction testing device according to any one of claims 1 to 3, characterized in that: A second branch is provided between the first regulating valve and the heat exchanger; Preferably, the second branch is connected to the gas recovery end.

5. The neutron diffraction testing device according to any one of claims 1 to 4, characterized in that: The second branch is provided with a second switch valve and a vacuum pump in sequence.

6. The neutron diffraction testing device according to any one of claims 1 to 5, characterized in that: A third switch valve and a third pressure reducing valve are sequentially arranged on the pipeline between the liquid helium end and the heat exchanger.

7. The neutron diffraction testing device according to any one of claims 1 to 6, characterized in that: The liquid helium end is equipped with a pressure detection device and a temperature detection device; Preferably, the outlet of the cold medium channel of the heat exchanger is connected to the gas recovery end.

8. The neutron diffraction testing device according to any one of claims 1 to 7, characterized in that: A fourth switch valve and a second regulating valve are sequentially arranged on the pipeline between the liquid hydrogen environment end and the gas recovery end; Preferably, the liquid hydrogen environment providing unit is equipped with a safety purge gas terminal.

9. A neutron diffraction test method for hydrogen storage materials in a liquid hydrogen environment, characterized in that: The neutron diffraction testing method comprises: Connecting the hydrogen end and the liquid helium end through a heat exchanger, liquefying the hydrogen with liquid helium to obtain liquid hydrogen; The liquid hydrogen enters the liquid hydrogen environment end to form a liquid hydrogen environment, and the hydrogen storage material is placed in the liquid hydrogen environment to perform a neutron diffraction test.

10. The neutron diffraction testing method according to claim 9, wherein: The hydrogen storage material includes: hydrogen storage functional material or hydrogen storage structural material; Preferably, the temperature of the liquid hydrogen environment is 15-25K; Preferably, the hydrogen used in the liquid hydrogen environment includes: deuterium gas; Preferably, the diffraction angle of the neutron diffraction test is 45-180°; Preferably, the neutron diffraction test comprises: placing the hydrogen storage material in a liquid hydrogen or liquid deuterium environment, collecting neutron diffraction spectra at different time points one by one as the standing time progresses, and analyzing the evolution of the crystal material structure in the hydrogen storage material.

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