Cold storage material, and preparation method therefor and use thereof
By preparing and applying Gd2O2Se crystals as a cold storage material, the problem of the lack of high-performance cold storage materials at liquid helium temperature was solved, and the 4K refrigerator achieved a high-efficiency cooling effect at low temperature.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- SHENZHEN INT QUANTUM ACAD
- Filing Date
- 2025-07-30
- Publication Date
- 2026-05-28
Smart Images
Figure CN2025111569_28052026_PF_FP_ABST
Abstract
Description
A cold storage material, its preparation method and application Technical Field
[0001] This application relates to the field of cold storage technology, and in particular to a cold storage material, its preparation method and application. Background Technology
[0002] GM (Gifford-Mcmahon) pulse tube refrigerators, especially the 4K high-capacity GM pulse tube refrigerator, play a crucial role in creating and maintaining cryogenic environments, and are widely used in condensed matter physics, quantum computing, cryogenic scientific instruments, superconductivity, and military applications. The efficiency of these refrigerators largely depends on the performance of the regenerator, the high specific heat capacity material filled within which is critical to cooling performance. However, the specific heat capacity of existing elemental materials decreases with decreasing temperature, and deteriorates significantly below 10 Kelvin (K), severely impacting refrigerator performance.
[0003] Magnetic cold storage materials have attracted attention due to their anomalously high specific heat at low temperatures. Materials such as HoCu2, Er3Ni, and gadolinium oxysulfide (Gd2O2S, or GOS) exhibit magnetic phase transitions below 10K, displaying anomalous specific heat characteristics that can significantly improve the performance of 4K refrigerators and are widely used in commercial refrigerators. Therefore, exploring novel low-temperature cold storage materials with high specific heat has become an important research direction.
[0004] Rare earth-based compounds, especially those containing elements such as gadolinium (Gd), dysprosium (Dy), and terbium (Tb), exhibit significant magnetocaloric effects due to their unpaired 4f electrons, making them potential candidates for cold storage applications. For example, gas osmosis (GOS), a high-entropy-density magnetic cold storage material suitable for temperature ranges from 4.2K to 20K, has been widely used in high-end technologies such as small-scale regenerative cryogenic gas refrigerators. Although existing layered filling strategies for HoCu2 and GOS have improved the specific heat capacity below 10K, a specific heat capacity trough exists between 6-7K, necessitating the research of new materials to fill this gap.
[0005] Potential GOS alternatives, such as gadolinium selenide and gadolinium telluride, possess similar physicochemical properties to GOS. However, due to the challenges in their preparation processes, the application of rare-earth oxygen selenides in cryogenic cold storage has not yet been developed. Therefore, the development of high-performance cold storage materials with significant magnetocaloric effects suitable for liquid helium temperatures is particularly urgent. This will promote the practical application of cold storage technology in the liquid helium temperature range and drive the development of cryogenic refrigeration technology. Summary of the Invention
[0006] In view of the shortcomings of the prior art, the purpose of this application is to provide a cold storage material, its preparation method and application, in order to solve the problem of the lack of high-performance cold storage materials that are suitable for liquid helium temperature and have significant magnetocaloric effect in the prior art.
[0007] The technical solution of this application is as follows:
[0008] A first aspect of this application provides a cold storage material, said cold storage material comprising Gd2O2Se crystals.
[0009] Optionally, the Gd2O2Se crystal belongs to the trigonal crystal system with space group P-3m1.
[0010] Optionally, the cell parameters of the Gd₂O₂Se crystal are as follows: α=90°, β=90°, γ=120°,
[0011] A second aspect of this application provides a method for preparing the cold storage material of the first aspect of this application, comprising the following steps: mixing Gd2O3, Se, activated carbon powder, CsCl and iodine particles in a predetermined ratio and grinding them to obtain a mixture powder; and sintering the mixture powder under vacuum conditions to obtain the cold storage material.
[0012] Optionally, the molar ratio of Gd2O3, Se, and activated carbon powder is 5:5:2.6-5:10:6; the mass ratio of CsCl to the sum of the masses of Gd2O3, Se, and activated carbon powder is 3:2; and the mass ratio of iodine particles to the sum of the masses of Gd2O3, Se, and activated carbon powder is 1:20-10:20.
[0013] Optionally, the specific steps of the sintering process include: heating to 950-1100 degrees Celsius at an initial temperature of 20-40 degrees Celsius within 600-800 minutes at a constant heating rate, holding at that temperature for 10-48 hours, then cooling to 500-750 degrees Celsius over 3-5 days, and finally cooling to room temperature within 10-48 hours.
[0014] A third aspect of this application provides the application of the cold storage material of the first aspect of this application in the preparation of cold storage equipment or refrigeration equipment.
[0015] A fourth aspect of this application provides a cold storage device, the cold storage device comprising a cold storage cylinder with a first partition, a second partition, and a third partition spaced apart within the cold storage cylinder, the first partition, the second partition, and the third partition being configured to allow airflow from the first partition to the third partition; the first partition, the second partition, and the cold storage cylinder forming a first accommodating space, the second partition, the third partition, and the cold storage cylinder forming a second accommodating space; the first accommodating space being filled with a front-end cold storage material and a middle-end cold storage material, and the second accommodating space being filled with a rear-end cold storage material.
[0016] Optionally, the front-end cold storage material includes at least one of Er3Ni, Pb, Bi, HoCu2, and Ni; the middle-end cold storage material includes the above-mentioned cold storage materials; and the rear-end cold storage material includes at least one of the above-mentioned cold storage materials and Gd2O2S.
[0017] Optionally, the phase transition temperatures of the front-end cold storage material, the middle-end cold storage material, and the rear-end cold storage material decrease sequentially.
[0018] The beneficial effects of this application are as follows: The cold storage material in this application includes Gd2O2Se crystal. Gd2O2Se crystal undergoes a phase transformation near 6.22K and has a large specific heat in the temperature range of 1-10K, exhibiting a significant magnetocaloric effect, and can be used as a cold storage material at liquid helium temperature. Attached Figure Description
[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below.
[0020] Figure 1 is a schematic flowchart of a method for preparing a cold storage material provided in this application;
[0021] Figure 2 is a structural schematic diagram of a cold storage device provided in this application;
[0022] Figure 3 is a physical image of a cold storage material provided in this application;
[0023] Figure 4 is an optical microscope image of a cold storage material provided in this application;
[0024] Figure 5 is a schematic diagram of the crystal structure of a cold storage material provided in this application;
[0025] Figure 6 is an X-ray diffraction test pattern of a powder of a cold storage material provided in this application;
[0026] Figure 7 shows the specific heat-temperature data variation curve of a cold storage material provided in this application.
[0027] Reference numerals: 100, cold storage equipment; 1, cold storage cylinder; 21, first partition component; 22, second partition component; 23, third partition component; 31, front-end cold storage material; 32, middle-end cold storage material; 33, rear-end cold storage material; 41, air inlet; 42, exhaust port. Detailed Implementation
[0028] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings and examples. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this application. Unless otherwise specified, the following embodiments and features can be combined with each other.
[0029] It should be noted that if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on enabling those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.
[0030] This application provides a cold storage material comprising Gd₂O₂Se crystal. The Gd₂O₂Se crystal undergoes a phase transition near 6.22 K and exhibits a large specific heat in the 1-10 K temperature range. Currently, there are no applications of rare earth selenides in low-temperature cold storage. Gd₂O₂Se crystal, with its significant magnetocaloric effect, can be used as a cold storage material at liquid helium temperatures.
[0031] In some embodiments, the Gd₂O₂Se crystal belongs to the trigonal crystal system with space group P-3m₁.
[0032] In some implementations, the cell parameters of the Gd₂O₂Se crystal are: α=90°, β=90°, γ=120°,
[0033] This application also provides a method for preparing the cold storage material as described above, including the following steps:
[0034] Gd2O3, Se, activated carbon powder, CsCl and iodine particles were mixed in a certain proportion and then ground to obtain a mixture powder.
[0035] The mixture powder is sintered under vacuum conditions to obtain a cold storage material.
[0036] In some embodiments, the molar ratio of Gd₂O₃, Se, and activated carbon powder is 5:5:2.6-5:10:6, for example, 5:5:2.6, 5:5:5, 5:6:5, 5:8:6, or 5:10:5. The mass ratio of CsCl to the sum of the masses of Gd₂O₃, Se, and activated carbon powder is 3:2-3:5. For example, the mass ratio of CsCl to the sum of the masses of Gd₂O₃, Se, and activated carbon powder is 3:2, 3:3, 3:4, or 3:5. The mass ratio of iodine particles to the sum of the masses of Gd2O3, Se and activated carbon powder is 1:20-10:20. For example, the mass ratio of iodine particles to the sum of the masses of Gd2O3, Se and activated carbon powder is 1:20, 2:20, 3:20, 4:20, 6:20, 8:20, 9:20 or 10:20, etc.
[0037] In some embodiments, the specific steps of the sintering process include: heating to 950-1100 degrees Celsius at an initial temperature of 20-40 degrees Celsius over 600-800 minutes at a constant heating rate, holding at that temperature for 10-48 hours, cooling to 500-750 degrees Celsius over 3-5 days, and finally cooling to room temperature over 10-48 hours.
[0038] In some embodiments, referring to Figure 1, the method for preparing the cold storage material includes the following steps:
[0039] S1: Gd2O3 powder, Se powder, activated carbon powder, CsCl powder and iodine (I2) particles are mixed uniformly in a certain proportion and then ground to obtain a mixture powder.
[0040] The molar ratio of Gd2O3, Se and activated carbon powder is 5:5:2.6-5:10:6, the mass ratio of CsCl to the sum of the masses of Gd2O3, Se and activated carbon powder is 3:2, and the mass ratio of iodine particles to the sum of the masses of Gd2O3, Se and activated carbon powder is 1:20-10:20.
[0041] The amount of Gd2O3 powder, Se powder, and activated carbon powder added will affect the phase composition of the product. If the amount is lower than the above molar ratio, it will be difficult to synthesize the desired phase. If the amount added is too much or higher than the above molar ratio, impurity phases will be generated. CsCl powder is a co-solvent and will affect the phase synthesis. I2 particles are used to control the growth rate and generate the atmosphere required for synthesis, which will affect the phase synthesis.
[0042] S2: The mixture powder is filled into a quartz tube and vacuum sealed to obtain a mixture reaction vacuum quartz tube.
[0043] The quartz tube has a thickness of 1 mm or more, an outer diameter of 20 mm, and a sealing height of 100-200 mm.
[0044] S3: The mixture is placed in a high-temperature heating furnace for high-temperature reaction and sintering in a vacuum quartz tube.
[0045] The sintering temperature is set as follows: initial temperature 20-40 degrees Celsius, then heated to 950-1100 degrees Celsius after 600-800 minutes; held at 950-1100 degrees Celsius for 10-48 hours, then cooled to 500-750 degrees Celsius after 3-5 days; and finally cooled to room temperature after 10-48 hours from 500-750 degrees Celsius.
[0046] The melting and mixing of reactants can be controlled by adjusting the heating time and temperature. If the temperature is below the above range, the melting and mixing of reactants will be insufficient, while if it is too high, there will be safety risks. Crystal growth can be controlled by adjusting the holding time, cooling time, and cooling temperature. If the temperature is too low, the product will be difficult to synthesize.
[0047] S4: The sintered product is ultrasonically cleaned to obtain the low-temperature cold storage Gd2O2Se crystal.
[0048] The ultrasonic cleaning time is set to 24-72 hours, and the ultrasonic cleaning solution is ultrapure water.
[0049] This application also provides an application of the cold storage material described above in the preparation of cold storage equipment or refrigeration equipment.
[0050] Referring to Figure 2, this application embodiment also provides a cold storage device 100, which generally includes a cold storage cylinder 1 and a first partition 21, a second partition 22, and a third partition 23 spaced apart within the cold storage cylinder 1. The first partition 21, the second partition 22, and the third partition 23 are configured to allow airflow from the first partition 21 to the third partition 23 (direction F). The first partition 21 forms an air inlet 41, and the third partition forms an exhaust outlet 42. The first partition 21 and the second partition 22 form a first accommodating space with the cold storage cylinder 1, and the second partition 22 and the third partition 23 form a second accommodating space with the cold storage cylinder 1. The first accommodating space is filled with a front-end cold storage material 31 and a middle-end cold storage material 32, and the second accommodating space is filled with a rear-end cold storage material 33. In one embodiment, the front-end cold storage material 31 and the middle-end cold storage material 32 in the first space can be mixed in proportion, used individually, or not mixed.
[0051] In some embodiments, the front-end cold storage material 31 includes at least one of Er3Ni, Pb, Bi, HoCu2, and Ni; the middle-end cold storage material 32 includes the cold storage material as described above; and the rear-end cold storage material 33 includes at least one of the cold storage material as described above and Gd2O2S.
[0052] Furthermore, the phase transition temperatures of the front-end cold storage material 31, the middle-end cold storage material 32, and the rear-end cold storage material 33 decrease sequentially.
[0053] When the refrigerant gas flows into the cold storage device 100 through the inlet 41, it exchanges heat with the secondary cold storage materials (front-stage cold storage material 31, middle-stage cold storage material 32, and rear-stage cold storage material 33) inside the cold storage device 100, and then exits from the outlet 42. In this process, the refrigerant gas transfers its own heat to the secondary cold storage materials, and further cooling is achieved through different ratios of the secondary cold storage materials.
[0054] The following will provide further explanation through specific embodiments.
[0055] Example 1
[0056] S1. Gd₂O₃ powder, Se powder, activated carbon powder, CsCl powder, and iodine (I₂) particles are uniformly mixed in a certain proportion and then ground to obtain a mixture powder. The molar ratio of Gd₂O₃, Se, and activated carbon powder is 5:7:2.6, the mass ratio of CsCl to the sum of the masses of Gd₂O₃, Se, and activated carbon powder is 3:2, and the mass ratio of iodine particles to the sum of the masses of Gd₂O₃, Se, and activated carbon powder is 3:20.
[0057] S2. Fill the quartz tube with the mixture powder and perform vacuum sealing to obtain the mixture reaction vacuum quartz tube.
[0058] S3. Place the mixture reaction vacuum quartz tube in a high-temperature heating furnace for high-temperature reaction and sintering. The specific temperature is set as follows: at an initial temperature of 30 degrees Celsius, heat to 1050 degrees Celsius within 600 minutes at a constant heating rate, hold for 24 hours, then cool down to 700 degrees Celsius after 3 days, and finally cool to room temperature within 24 hours.
[0059] S4. After ultrasonically cleaning the sintered product with ultrapure water for 24 hours, Gd2O2Se crystals (cold storage material) are obtained.
[0060] Example 2
[0061] S1. Gd₂O₃ powder, Se powder, activated carbon powder, CsCl powder, and iodine (I₂) particles are uniformly mixed in a certain proportion and then ground to obtain a mixed powder. The molar ratio of Gd₂O₃, Se, and activated carbon powder is 5:5:2.6, the mass ratio of CsCl to the sum of the masses of Gd₂O₃, Se, and activated carbon powder is 3:2, and the mass ratio of iodine particles to the sum of the masses of Gd₂O₃, Se, and activated carbon powder is 1:20.
[0062] S2. Fill the quartz tube with the mixture powder and perform vacuum sealing to obtain the mixture reaction vacuum quartz tube.
[0063] S3. Place the mixture reaction vacuum quartz tube in a high-temperature heating furnace for high-temperature reaction and sintering. The specific temperature is set as follows: at an initial temperature of 20 degrees Celsius, heat to 950 degrees Celsius within 600 minutes at a constant heating rate, hold at that temperature for 48 hours, then cool down to 700 degrees Celsius after 3 days, and finally cool down to room temperature within 10 hours.
[0064] S4. After ultrasonically cleaning the sintered product with ultrapure water for 24 hours, Gd2O2Se crystals (cold storage material) are obtained.
[0065] Example 3
[0066] S1. Gd₂O₃ powder, Se powder, activated carbon powder, CsCl powder, and iodine (I₂) particles are uniformly mixed in a certain proportion and then ground to obtain a mixture powder. The molar ratio of Gd₂O₃, Se, and activated carbon powder is 5:10:6, the mass ratio of CsCl to the sum of the masses of Gd₂O₃, Se, and activated carbon powder is 3:2, and the mass ratio of iodine particles to the sum of the masses of Gd₂O₃, Se, and activated carbon powder is 10:20.
[0067] S2. Fill the quartz tube with the mixture powder and perform vacuum sealing to obtain the mixture reaction vacuum quartz tube.
[0068] S3. Place the mixture reaction vacuum quartz tube in a high-temperature heating furnace for high-temperature reaction and sintering. The specific temperature is set as follows: at an initial temperature of 40 degrees Celsius, heat up to 1100 degrees Celsius within 800 minutes at a constant heating rate, hold at that temperature for 24 hours, then cool down to 500 degrees Celsius after 5 days, and finally cool down to room temperature within 48 hours.
[0069] S4. After ultrasonically cleaning the sintered product with ultrapure water for 72 hours, Gd2O2Se crystals (cold storage material) are obtained.
[0070] Test Example 1
[0071] Compositional and crystal structure analysis experiments were conducted on the Gd2O2Se crystals prepared in Example 1.
[0072] (1) The structure of the prepared Gd2O2Se crystal was characterized.
[0073] As shown in Figure 3, under the microscope of the Bruker D8 VENTURE single crystal diffractometer, the crystal exhibits the appearance of a transparent hexagonal prism and has corresponding crystal facet features.
[0074] As shown in Figure 4, the crystal exhibits a transparent crystal structure under an optical microscope.
[0075] As shown in Figure 5, the structure of Gd2O2Se crystal was tested under the test conditions of Bruker D8 VENTURE single crystal diffractometer, Mo target, Kα radiation source (wavelength = 0.07107 nm), and test temperature of 100 K. The structure was analyzed by Olex2 software. The obtained Gd2O2Se crystal data are shown in Table 1.
[0076] Table 1 Gd₂O₂Se crystal data parameters
[0077] (2) The prepared Gd2O2Se crystals were characterized by composition.
[0078] The obtained Gd₂O₂Se crystal powder was tested using a Rigaku SmartLab 9KW powder X-ray diffractometer. The results are shown in Figure 6. The obtained spectrum is basically consistent with the standard XRD spectrum, proving that the target compound Gd₂O₂Se single crystal powder was successfully prepared.
[0079] Test Example 2
[0080] The properties of the Gd2O2Se crystal prepared in Example 1 were tested.
[0081] The specific heat data of the crystal samples prepared in Example 1 were measured using Proportional Physical Measurement (PPMS). The single crystal samples prepared in Example 1 were fixed on a specific heat stage with a low-temperature adhesive for data testing. The specific heat (C) was measured at a magnetic field of 0T. p The specific heat versus temperature curve is shown in Figure 7. To investigate the contribution of the magnetic phase transition to specific heat in Gd₂O₂Se, data from 24-50 K were subjected to a double Debye fit, and the fitted curve was extended to 1.8 K to obtain the phonon specific heat value. Subtracting the fitted phonon specific heat value from the measured specific heat value gives the magnetic specific heat value. Figure 7 shows the specific heat-temperature curve, which clearly shows a phase transition around 6.22 K and a large specific heat in the 1-10 K temperature range, with a peak specific heat of 55.48 J / mol. 3 K. Furthermore, as the magnetic field gradually increases, the phase transition is gradually suppressed, demonstrating high cold storage availability.
[0082] In summary, the cold storage material in this application includes Gd₂O₂Se crystal. Gd₂O₂Se crystal undergoes a phase transition near 6.22K and exhibits a large specific heat in the 1-10K temperature range, demonstrating a significant magnetocaloric effect, making it suitable as a cold storage material at liquid helium temperatures. The preparation method of the cold storage material in this application utilizes a fluxing agent method for crystal growth, which is simple to operate, uses readily available raw materials, and has a high experimental safety factor. The resulting cold storage material possesses advantages such as stable physicochemical properties, good mechanical properties, resistance to deliquescence, and ease of storage, which are beneficial for subsequent processing and applications. The cold storage device in this application combines materials with different specific heat characteristics within a two-stage cold accumulator. The phase transition temperatures of the cold storage materials decrease progressively from front to back. As gas flows through the cold accumulator, a multi-stage cooling process occurs, ultimately achieving more efficient cooling in the two-stage cold accumulator.
[0083] It should be understood that the application of this application is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.
Claims
1. A cold storage material, characterized in that, The cold storage material includes Gd2O2Se crystals.
2. The cold storage material according to claim 1, characterized in that, The Gd2O2Se crystal belongs to the trigonal crystal system with space group P-3m1.
3. The cold storage material according to claim 1, characterized in that, The cell parameters of the Gd₂O₂Se crystal are as follows: α=90°, β=90°, γ=120°, 4. A method for preparing a cold storage material according to any one of claims 1 to 3, characterized in that, Includes the following steps: Gd2O3, Se, activated carbon powder, CsCl and iodine particles were mixed in a predetermined ratio and then ground to obtain a mixture powder. The mixture powder is sintered under vacuum conditions to obtain a cold storage material.
5. The preparation method according to claim 4, characterized in that, The molar ratio of Gd2O3, Se and activated carbon powder is 5:5:2.6-5:10:6; The mass ratio of CsCl to the sum of the masses of Gd2O3, Se, and activated carbon powder is 3:2-3:
5. The mass ratio of the iodine particles to the sum of the masses of Gd2O3, Se, and activated carbon powder is 1:20-10:
20.
6. The preparation method according to claim 4, characterized in that, The specific steps of the sintering process include: heating to 950-1100 degrees Celsius at an initial temperature of 20-40 degrees Celsius within 600-800 minutes at a constant heating rate, holding at that temperature for 10-48 hours, cooling to 500-750 degrees Celsius after 3-5 days, and finally cooling to room temperature within 10-48 hours.
7. The use of the cold storage material according to any one of claims 1 to 3 in the preparation of cold storage equipment or refrigeration equipment.
8. A cold storage device, characterized in that, The cold storage device includes a cold storage cylinder with a first partition, a second partition, and a third partition spaced apart within the cold storage cylinder. The first partition, the second partition, and the third partition are configured to allow air to pass through from the first partition to the third partition. The first separating component, the second separating component, and the cold storage cylinder form a first accommodating space; the second separating component, the third separating component, and the cold storage cylinder form a second accommodating space. The first accommodating space is filled with front-end cold storage material and middle-end cold storage material, and the second accommodating space is filled with rear-end cold storage material.
9. The cold storage device according to claim 8, characterized in that, The front-end cold storage material includes at least one of Er3Ni, Pb, Bi, HoCu2, and Ni; The mid-section cold storage material includes the cold storage material according to any one of claims 1 to 3; The downstream cold storage material includes at least one of the cold storage materials described in any one of claims 1 to 3 and Gd2O2S.
10. The cold storage device according to claim 9, characterized in that, The phase transition temperatures of the front-end cold storage material, the middle-end cold storage material, and the rear-end cold storage material decrease sequentially.