Hydrocarbon normal-pressure superconducting material and preparation method thereof

Abstract

The invention discloses a hydrocarbon normal-pressure superconducting material and a preparation method thereof. The preparation method comprises the following steps: performing high-temperature pressurizing pressing treatment on graphite and hydrogen under a closed condition to obtain the hydrocarbon normal-pressure superconducting material. The superconducting material provided by the invention can realize superconducting phase change under normal pressure, effectively solves the limitation that an existing hydrogen-based superconductor needs extremely high pressure, has a critical superconducting temperature far higher than that of a traditional normal-pressure superconducting material under normal pressure, has a space structure almost unchanged under different pressures (0-100 GPa), has relatively high stability, and can be applied to the field of superconducting materials. The method has potential application value in industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of superconducting materials, and in particular to a carbon-hydrogen normal-pressure superconducting material and a preparation method thereof. Background Art

[0002] Superconducting materials have the property of disappearing resistance at a specific temperature, and therefore play a vital role in many fields such as energy, information electronics and quantum devices. At present, superconducting materials are mainly divided into the following categories: traditional superconductors, copper-based superconductors, iron-based superconductors, heavy fermion superconductors, interface superconductors, organic superconductors and hydrogen-based superconductors, and the latter two are classified as light element superconductors relative to copper-based and iron-based systems. These materials usually require extremely high pressure to achieve a superconducting state, often exceeding 150GPa (i.e. 1.5 million atmospheres), which is extremely difficult to achieve under laboratory conditions, limiting their large-scale preparation and practical application. In addition, the superconductivity phenomenon was first observed under low temperature conditions close to absolute zero, and most superconductors must operate in a temperature environment below 40K (about -233.15°C), which is far below room temperature.

[0003] Hydrogen-based superconductors have potential applications at high temperatures or room temperature and are considered to be one of the strong candidates for future high-temperature or even room-temperature superconductors. Many research teams are working on exploring various hydrogen-based high-temperature superconductors. However, the working pressure of existing hydrogen-based superconductors is too high, higher than 150GPa, and it is impossible to achieve normal-pressure superconductivity. Summary of the invention

[0004] In view of the above technical problems, the present invention provides a carbon-hydrogen normal-pressure superconducting material and a preparation method thereof, which can stably operate under conventional conditions such as industrial environments and daily life, thereby expanding the scope of application.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] In one aspect, the present invention provides a method for preparing a carbon-hydrogen atmospheric-pressure superconducting material, comprising the following steps:

[0007] Under closed conditions, graphite and hydrogen are subjected to high-temperature pressurization treatment to obtain the carbon-hydrogen normal-pressure superconducting material.

[0008] In the technical solution of the present invention, the usage of the graphite and hydrogen is not particularly limited, and preferably the molar ratio of the graphite to hydrogen is 3 to 12:1.

[0009] As a preferred embodiment, the pressure of the pressurization treatment is 5 GPa to 30 GPa.

[0010] As a preferred implementation, the high temperature is 2000K to 3000K.

[0011] As a preferred embodiment, the preparation method specifically comprises the following steps:

[0012] The powdered graphite sample is subjected to tabletting treatment to obtain a flake graphite sample;

[0013] Using a diamond anvil as a pressure device, the gasket is pre-pressed to form an indentation on the gasket; a hole is punched at the center of the indentation to accommodate a flake graphite sample;

[0014] Put the flake graphite sample into the hole, introduce hydrogen, and press it with a diamond anvil at 2000K to 3000K;

[0015] In the technical solution of the present invention, the stability of the gasket and the smooth progress of the subsequent pressurization and pressing process can be ensured by pre-pressing and punching;

[0016] In some specific embodiments, the gasket is a rhenium sheet or a T301 stainless steel sheet, the diamond anvil uses helium as the pressure transmission medium, and ruby ​​as the pressure standard material; wherein the material of the gasket has no particularly significant effect on the performance of the prepared carbon-hydrogen normal-pressure superconducting material; using ruby ​​as the pressure standard material, the displacement of its fluorescence peak under pressure change can be used as an indication of pressure; the above-mentioned arrangement can ensure the accuracy and reliability of the preparation process.

[0017] As a preferred embodiment, the pressure of the pre-pressing treatment is 5 to 30 GPa.

[0018] As a preferred implementation, the introducing helium gas is introducing compressed helium gas; the pressure of the compressed helium gas is 0.1-0.5 GPa.

[0019] In another aspect, the present invention provides a carbon-hydrogen normal-pressure superconducting material obtained by the above preparation method.

[0020] In some specific embodiments, the molecular formula of the carbon-hydrogen atmospheric-pressure superconducting material is HC 6 .

[0021] In some specific embodiments, the critical superconducting temperature of the carbon-hydrogen normal-pressure superconducting material at normal pressure is above 100K.

[0022] The present invention has the following advantages and beneficial effects:

[0023] The carbon-hydrogen normal-pressure superconducting material provided by the present invention is prepared by high-temperature pressure treatment under closed conditions using graphite and hydrogen as reaction raw materials. The molecular formula of the carbon-hydrogen normal-pressure high-temperature superconducting material is HC 6, can achieve superconducting phase transition at normal pressure, effectively solving the limitation of extremely high pressure required for existing hydrogen-based superconductors. Its critical superconducting temperature at normal pressure is above 100K, which is much higher than traditional normal-pressure superconducting materials. Moreover, under different pressures (0-100GPa), its spatial structure hardly changes, and it has high stability, which has potential application value in industrial production.

[0024] In addition, the preparation method provided by the present invention is not only simple in process and high in efficiency, but also easy to control in operating conditions, which greatly expands the range of superconducting material selection and provides more possibilities for its application in multiple industries. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the structure of the diamond anvil used in the embodiment of the present invention;

[0026] Figure 2 Schematic diagram of a gas sealing device used in an embodiment of the present invention;

[0027] Figure 3 This is a crystal structure diagram of the carbon-hydrogen normal-pressure superconducting material prepared in Example 1 of the present invention;

[0028] Figure 4 The electronic state density spectrum of the carbon-hydrogen normal-pressure superconducting material prepared in Example 1 of the present invention;

[0029] Figure 5 The phonon spectrum, Ilie Eberg spectrum function and electroacoustic coupling integral diagram of the carbon-hydrogen normal-pressure superconducting material prepared in Example 1 of the present invention are shown. DETAILED DESCRIPTION

[0030] The following embodiments are only some embodiments of the present invention, rather than all embodiments. Therefore, the detailed description in the embodiments of the present invention provided below is not intended to limit the scope of the present invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the protection scope of the present invention.

[0031] In the present invention, unless otherwise specified, all equipment and raw materials can be purchased from the market or are commonly used in the industry. The methods in the following embodiments are all conventional methods in the art unless otherwise specified.

[0032] Example 1

[0033] In this embodiment, a 99.9% pure powdered graphite sample from Jusheng Graphite (China) Products Co., Ltd. is used as a reaction raw material. First, the powdered graphite sample is pressed into sheets to obtain a flake graphite sample 112. The thickness of the obtained sample sheet is about 20 μm.

[0034] In this embodiment, a diamond anvil is used as a pressure device, and the structural diagram is shown in Figure 1 , a rhenium sheet is used as a gasket 11, helium is used as a pressure transmission medium, the diameter of the anvil is 300 μm, a ruby ​​ball 111 is placed in the sample chamber of the diamond anvil as an internal pressure standard, and the pressure is calibrated by the movement of the fluorescence peak of the ruby ​​under pressure, and 12 is a metal sealing ring;

[0035] A diamond anvil is used to press a dent on the rhenium sheet at a pressure of 5 GPa, and then a hole is drilled in the center of the dent (not shown in the figure), and then the flake graphite sample 112 is placed in the center of the hole; Figure 2 The gas sealing device shown is filled with hydrogen, specifically as follows: the diamond anvil is placed in a sealed container with a gas channel as shown in the figure, the hydrogen is compressed to 0.15 GPa by a compressor, and then injected into the sealed container through the gas channel, and the molar ratio of graphite to hydrogen is controlled to be 12:1; the diamond anvil is used to apply a pressure of 20 GPa to the flake graphite sample 112 and hydrogen, and the temperature range inside the device is maintained at 2500K to obtain a pressurized product; during the pressurized pressing process, the diamond anvil is closed in a high-pressure encapsulated gas environment to allow the hydrogen encapsulation to enter the sample cavity of the diamond anvil.

[0036] The crystal structure of the carbon-hydrogen normal-pressure superconducting material prepared in this embodiment is measured by CALYPSO software as shown in Figure 3 As shown. Figure 3 It can be seen that the above-mentioned carbon-hydrogen normal-pressure superconducting material is composed of carbon atoms and hydrogen atoms in a molar ratio of 6:1, and the molecular formula is HC 6 .

[0037] The electronic state density spectrum of the carbon-hydrogen normal-pressure superconducting material prepared in this example is as follows Figure 4 As shown, Figure 4 The metallization characteristics of the product at normal pressure were demonstrated, which is a prerequisite for the normal pressure product to have superconductivity.

[0038] Figure 5 The phonon spectrum, Eli Eberg spectrum function and electroacoustic coupling integral diagram of the carbon-hydrogen normal-pressure superconducting material prepared in this embodiment are shown in FIG. Figure 5 It can be obtained that the electroacoustic coupling constant λ = 2.68, the logarithm of the phonon frequency is 443.6K, and the enhancement factor f 1 f 2 =1.414, using the electron Coulomb screening potential μ*=0.1, the superconducting transition temperature T is calculated by the following formula (1): c Therefore, the carbon-hydrogen normal-pressure superconducting material prepared in this embodiment can achieve superconducting transition at a temperature of 107K, that is, a superconducting material with a critical temperature of 107K under normal pressure.

[0039]

[0040] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a carbon-hydrogen normal-pressure superconducting material, characterized in that: The following steps are involved: Under closed conditions, graphite and hydrogen are subjected to high-temperature pressurization treatment to obtain the carbon-hydrogen normal-pressure superconducting material.

2. The preparation method according to claim 1, characterized in that: The molar ratio of the graphite to hydrogen is 3 to 12:

1.

3. The preparation method according to claim 2, characterized in that: The molar ratio of the graphite to the hydrogen is 12:

1.

4. The preparation method according to claim 1, characterized in that: The pressure of the pressurization treatment is 5 GPa to 30 GPa.

5. The preparation method according to claim 1, characterized in that: The high temperature is 2000K to 3000K.

6. The preparation method according to claim 1, characterized in that: The preparation method specifically comprises the following steps: The powdered graphite sample is subjected to tabletting treatment to obtain a flake graphite sample; Using a diamond anvil as a pressure device, the gasket is pre-pressed to form an indentation on the gasket; a hole is punched at the center of the indentation to accommodate a flake graphite sample; The flake graphite sample is placed in the hole, hydrogen is introduced, and a diamond anvil is used to perform pressure pressing at 2000K to 3000K.

7. The preparation method according to claim 6, characterized in that: The pre-pressing treatment pressure is 5 to 30 GPa.

8. The preparation method according to claim 6, characterized in that: The introducing of hydrogen is introducing of compressed hydrogen.

9. The preparation method according to claim 8, characterized in that: The pressure of the compressed hydrogen is 0.1-0.5 GPa.

10. The carbon-hydrogen normal-pressure superconducting material obtained by the preparation method according to any one of claims 1 to 9.

Images