Application method of graphene-based paper-cut configuration in solid-state refrigeration

Abstract

The invention discloses an application method based on a graphene paper-cut configuration in solid-state refrigeration, the graphene paper-cut configuration can be used as a refrigeration working medium in solid-state refrigeration, and the graphene paper-cut configuration generates a heat effect to carry out solid-state refrigeration under the driving of uniaxial stress; according to the graphene paper-cutting operation structure, graphene is cut, and the structure which can generate out-of-plane overturning after being stretched is obtained. The graphene paper-cutting structure can generate isothermal entropy change of 60 J * kg <-1 > * K <-1 > and adiabatic temperature change of 25 K under the pressure of less than 50 MPa. The material has a large refrigeration interval, does not depend on the phase change point of the material, can be stretched and compressed to generate temperature change in any temperature zone, and is far superior to other solid refrigeration material systems. Meanwhile, the heat conductivity of the material is high and can reach 62W. M <-1 >. K <-1 >, and although the paper-cut structure weakens the heat conduction of the graphene, the heat conductivity of the material is still far higher than that of a traditional solid refrigeration material.

Description

Technical Field

[0001] The present invention relates to the field of solid-state refrigeration technology, and in particular to an application method based on a graphene kirigami configuration in solid-state refrigeration. Background Art

[0002] Solid-state refrigeration technology is widely considered to be one of the most promising technologies to replace traditional gas compression refrigeration due to its many advantages, especially refrigeration solutions based on solid-state phase change thermal effects (such as magnetic card effect, electrocaloric effect, spring card effect and pressure card effect). By applying an external field to induce reversible thermal changes in materials, efficient energy conversion can be achieved. This type of technology has the characteristics of low energy consumption, low noise, low maintenance cost and zero carbon emissions, and shows broad application prospects in aerospace and space exploration, electronic equipment cooling, medical and biotechnology, and home appliance industries. From the perspectives of environmental protection, economy, feasibility and foresight, solid-state refrigeration technology has become an important research direction for the next generation of green refrigeration technology.

[0003] However, existing solid-state refrigeration materials usually require a driving field of more than hundreds of MPa, and the refrigeration area is limited to the vicinity of the phase change point. At the same time, the low thermal conductivity limits the transfer of heat, making it difficult to achieve large-scale application. Therefore, how to fundamentally improve the comprehensive performance of solid-state refrigeration materials has become a frontier and core issue in this field. In recent years, the rapid development of two-dimensional materials has provided a new idea for this problem. Since graphene was first stripped from graphite in 2004, it has been found that two-dimensional materials can exist stably at room temperature and pressure. As a two-dimensional carbon material with excellent electrical conductivity, thermal conductivity, mechanical strength and chemical stability, graphene has shown broad application prospects in new energy, environmental protection, medical care, electronics and other fields due to its unique physical and chemical properties. In 2024, researchers discovered a huge card effect on origami graphene, which provided new ideas and insights for the field of solid-state refrigeration. By applying the origami configuration to thermoplastic polyurethane elastomers, the effectiveness of the origami strategy was confirmed. Compared with traditional refrigeration materials that rely on phase change temperature, this material can be used for refrigeration in a wide temperature range of 100-600K, but experimentally measured adiabatic temperature change of 14K, which still has room for improvement.

[0004] Graphene's thermal conductivity of thousands of kilometres is exactly what solid-state refrigeration materials require, but its high stress and high cost limit its large-scale application. To this end, researchers used paper-kirigami technology to transform graphene to form a graphene paper-kirigami configuration. This technology introduces an out-of-plane flipping area during the stretching process, which greatly reduces the driving force of graphene. Introducing this new material into the field of solid-state refrigeration will be of great help in promoting the practical application of solid-state refrigeration technology. Summary of the invention

[0005] Purpose of the invention: In order to overcome the above shortcomings, the purpose of the present invention is to provide an application method based on graphene kirigami configuration in solid-state refrigeration, which can perform graphene kirigami structure design based on molecular dynamics simulation, calculate the key performance parameters of solid-state refrigeration of the material and introduce this new material into the field of solid-state refrigeration.

[0006] In order to solve the above technical problems, the present invention provides an application method based on graphene kirigami configuration in solid-state refrigeration, comprising: Step S1: designing a graphene kirigami configuration; Step S2: Simulating the refrigeration cycle process: using molecular dynamics calculations to simulate the refrigeration cycle process of different graphene kirigami configurations to generate materials that can stably perform a reversible refrigeration cycle; Step S3: Adiabatic temperature change test: statistically analyze the adiabatic temperature change of the graphene kirigami configuration during the stretching and contraction process to obtain the adiabatic temperature change data of the material; Step S4: Isothermal entropy change test: the material is heated and the specific heat capacity is calculated, and then the isothermal entropy change during the cooling process is calculated by the Clausius-Clapeyron equation; Step S5: Refrigeration performance test: Count the total energy change of the graphene kirigami configuration during the stretching and contraction process, obtain input work data, and calculate the heat according to the temperature change and specific heat capacity through the definition of heat, and calculate the refrigeration performance according to the work and heat; Step S6: driving pressure test: by stretching at both ends, outputting stress and strain curves, and obtaining driving pressures under different strains; Step S7: Calculate thermal conductivity through the temperature gradient of heat conduction according to the method of non-equilibrium molecular dynamics.

[0007] In one aspect of the present application, in step S1, the application further comprises: Step S11: using the paper-cutting technology, designing a cut graphene paper-cut configuration to reduce the driving force; Step S12: constructing a structural model and performing a hydrogenation operation on the structural model; Step S13: Design a variety of configurations using modeling software and compare refrigeration performance parameters to screen and generate the optimal graphene paper-kirigami configuration.

[0008] In one aspect of the present application, in step S12, the hydrogenation operation includes: allowing the edge carbon atom to adsorb a hydrogen atom to ensure that covalent bonds are not generated between adjacent edge carbon atoms during the stretching process.

[0009] In one aspect of the present application, in step S2, the application further comprises: Step S21: Select a preset potential function; Step S22: Set the simulation box to apply periodic boundary conditions along the y and z directions, set the x direction as the stretching direction and set the x direction as a fixed boundary.

[0010] In one aspect of the present application, in step S2, the simulation process further includes: Step S23: assigning a velocity to each atom according to Gaussian distribution, so that the whole reaches a preset room temperature, and then using an isothermal and isobaric ensemble to relax the material at room temperature and pressure for a first preset time, so that the structure is stable and parameters such as energy and force converge to a minimum value; Step S24: performing a stretching process: using an isobaric and isoenthalpic ensemble, stretching the graphene kirigami configuration along the x direction; Step S25: performing a heat release process: fixing the position of the material unchanged, using an isothermal and isobaric ensemble, returning the material to a preset room temperature, simulating contact with a heat source in the experiment, and releasing the heat generated by the material heating; Step S26: performing a contraction process: using an isobaric and isoenthalpic ensemble to contract the graphene kirigami configuration along the x direction; Step S27: Perform heat absorption process: fix the position of the material and use an isothermal and isobaric ensemble to return the material to a preset room temperature to simulate contact with the heat source in the experiment and absorb heat from a relatively high temperature heat source.

[0011] In one aspect of the present application, in step S3, the application further comprises: Step S31: Counting the temperature changes during the stretching process and the shrinking process and calculating the average value of the temperature changes; Step S32: Counting the temperature within the second preset time interval to generate temperature change curves of different processes; Step S33: Calculate the actual adiabatic temperature change of the material based on the heat capacity correction.

[0012] In one aspect of the present application, in step S4, the application further comprises: Step S41: simulating a heating process: raising the temperature from a first preset temperature to a second preset temperature, statistically analyzing the change in the total energy of the material as the temperature increases, and setting the slope as the specific heat capacity of the graphene kirigami configuration; Step S42: According to the Clausius-Clapeyron equation Calculate the isothermal entropy change, where C p is the specific heat capacity, ΔT is adiabatic temperature change, T It's the temperature.

[0013] In one aspect of the present application, in step S5, the application further includes: Step S51: Count the total energy change of the graphene kirigami configuration during the stretching and contraction process and subtract the two to obtain the input workW ; Step S52: Define by heat Get heat, where m It's quality. C p is the specific heat ΔT It is adiabatic temperature change; Step S53: Calculate refrigeration performance based on work done and heat .

[0014] In one aspect of the present application, in step S7, the application further includes: Step S71: According to the non-equilibrium molecular dynamics method, the heat transferred after forming a stable temperature gradient is counted: ; Step S72: Calculate thermal conductivity.

[0015] The present application also provides an application system based on graphene kirigami configuration in solid-state refrigeration, using the above-mentioned application method based on graphene kirigami configuration in solid-state refrigeration, including: Model design module, used to design graphene kirigami configurations; Refrigeration cycle module, used to simulate the refrigeration cycle process: using molecular dynamics calculations to simulate the refrigeration cycle process of different graphene kirigami configurations, to generate materials that can stably perform reversible refrigeration cycles; Adiabatic temperature change module, used for adiabatic temperature change test: statistically analyze the adiabatic temperature change of graphene kirigami configuration during stretching and contraction to obtain the adiabatic temperature change data of the material; Isothermal entropy change module, used for isothermal entropy change test: the material is heated and the specific heat capacity is calculated, and then the isothermal entropy change during the cooling process is calculated by the Clausius Clapeyron equation; Refrigeration test module, used for refrigeration performance test: statistics on the total energy change of the graphene kirigami configuration during the stretching and contraction process, obtain input work data, and calculate the heat according to the temperature change and specific heat capacity through the definition of heat, and calculate the refrigeration performance according to the work and heat; Pressure test module, used for driving pressure test: by stretching at both ends, outputting stress and strain curves, and obtaining driving pressure under different strains; The thermal conductivity calculation module is used to calculate the thermal conductivity through the temperature gradient of heat conduction according to the method of non-equilibrium molecular dynamics.

[0016] The above technical solution of the present application has the following advantages compared with the prior art: 1. The graphene kirigami configuration described in the present application can be used as a refrigerant in solid-state refrigeration. Under the drive of uniaxial stress, it produces a thermal effect for solid-state refrigeration; the graphene kirigami configuration is a configuration in which graphene is cut to produce an out-of-plane flipped configuration after stretching.

[0017] 2. The graphene kirigami configuration can produce an isothermal entropy change of 60 J·kg-1·K-1 and an adiabatic temperature change of 25K under a pressure less than 50MPa, which is greater than the adiabatic temperature change value of 14K obtained by the existing origami configuration experiment. In addition, this type of material has a large refrigeration range and does not depend on the phase transition point of the material. It can be stretched and compressed in any temperature zone to produce temperature changes, which is better than other solid refrigeration material systems. At the same time, this type of material has a high thermal conductivity, which can reach 62W·m -1 ·K -1 Although the paper-kirigami structure weakens the thermal conductivity of graphene, it is still much greater than that of traditional solid-state refrigeration materials. This application provides a powerful solution to replace traditional vapor compression technology, making the industrial application of solid-state refrigeration show broad prospects. It has broad application potential in many fields such as aerospace, space exploration, electronic equipment cooling, medical and biotechnology, and home appliance industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0019] Figure 1 It is a first flow chart of the method for applying the graphene kirigami configuration in solid-state refrigeration provided by an embodiment of the present invention.

[0020] Figure 2 It is a second flow chart of the method for applying graphene kirigami configuration in solid-state refrigeration provided by an embodiment of the present invention.

[0021] Figure 3 It is a model schematic diagram of the graphene kirigami configuration provided by an embodiment of the present invention.

[0022] Figure 4 It is a schematic diagram of a refrigeration cycle of the solid-state refrigeration technology provided by an embodiment of the present invention.

[0023] Figure 5 It is a schematic diagram of the adiabatic temperature change during the stretching and compression process of the graphene kirigami configuration provided by an embodiment of the present invention.

[0024] Figure 6It is a schematic diagram of the specific heat capacity of the graphene kirigami configuration during the heating process provided by an embodiment of the present invention.

[0025] Figure 7 It is a schematic diagram of the energy change during the stretching and compression process of the graphene kirigami configuration provided by an embodiment of the present invention.

[0026] Figure 8 It is a schematic diagram of module connections of an application system based on graphene kirigami configuration in solid-state refrigeration provided by an embodiment of the present invention.

[0027] Description of the Figures in the Specification: 101. Model design module, 102. Refrigeration cycle module, 103. Adiabatic temperature change module, 104. Isothermal entropy change module, 105. Refrigeration test module, 106. Pressure test module, 107. Thermal conductivity calculation module. DETAILED DESCRIPTION

[0028] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0029] This application proposes an application method based on graphene kirigami configuration in solid-state refrigeration, in the hope of obtaining excellent comprehensive refrigeration performance in the configuration material. The implementation case described is only a part of the present invention, not all implementation cases. It should be noted that in the specific implementation, the software calculation part involved is based on molecular dynamics and uses the LAMMPS program commonly used in the industry to calculate, so as to efficiently and accurately obtain the data in each step of the present invention.

[0030] Therefore, reference Figure 1 and Figure 2 As shown, in some embodiments, a method for applying a graphene kirigami configuration in solid-state refrigeration includes: Step 1: Since the driving force of graphene when stretched is large, the traditional paper cutting technology can be used to design the configuration of the cut graphene to reduce the driving force.

[0031] Specifically, the modeling software was used to design multiple configurations, and the refrigeration performance parameters were compared to screen out the optimal graphene configuration. That is, firstly, a graphene model with a length of 100Å and a width of 48Å was established, and a region with a length of 68Å and a width of 4.8Å was cut off in the middle of the graphene, and the system was expanded by 721 to obtain the graphene configuration as follows: Figure 3This configuration can ensure that the system produces out-of-plane deflection during the stretching process, reducing the driving force. At the same time, the smaller cutting area ensures a certain degree of integrity of the graphene material, allowing the material to maintain a high thermal conductivity.

[0032] Step 2: Based on the configuration designed in the first step, use Materials Studio software to construct a structural model and perform hydrogenation operation on the paper-cut structure.

[0033] Specifically, a hydrogen atom is adsorbed onto the edge carbon atom to ensure that the adjacent edge carbon atoms will not produce covalent bonds during the stretching process, which will affect the stretching process; a variety of materials designed using paper-cutting technology are exported as cif files, converted into data file format using ovito software, and molecular dynamics calculations are performed based on the configuration to simulate the refrigeration process.

[0034] Step 3: Based on the Materials Studio software in the second step, the structural model is constructed, and the LAMMPS software is used to simulate the refrigeration cycle process of the graphene kirigami configuration.

[0035] Specifically, the in file, potential function file and structure data file are used as input files. The potential function uses the airebo potential function, which is more accurate for simulating carbon and hydrogen atoms. The long-range van der Waals force and Coulomb interaction are calculated by the particle-particle-particle mesh k-space solver. The input file uses an isothermal and isobaric ensemble in the simulation, and the temperature and pressure are controlled by using pressure regulation and temperature regulation techniques.

[0036] The simulation box is subjected to periodic boundary conditions along the y and z directions, and the x direction is set as a fixed boundary as the stretching direction. The integration uses the Verlet algorithm with a time step of 1 fs.

[0037] Step 4: Based on the calculation details in step 3, write the input file, which includes the relaxation process and the refrigeration cycle process. The refrigeration cycle includes two adiabatic processes and two isothermal processes.

[0038] Specifically, after reading the structure file, the relaxation process assigns a velocity to each atom according to the Gaussian distribution so that the whole reaches room temperature of 300K. Then, an isothermal and isobaric ensemble is used to relax the material for 100 picoseconds at room temperature and normal pressure to stabilize the structure and converge parameters such as energy and force to the minimum value.

[0039] Step 5: According to the structure after relaxation in step 4, the refrigeration cycle is carried out, referring to Figure 4-Figure 7 shown.

[0040] Specifically, the first cycle is the stretching process, which is an adiabatic process. The graphene kirigami configuration is stretched along the x direction using an isobaric and isoenthalpic ensemble. That is, the velocity command is used to give the atoms on the right side of the material a rightward velocity, so that the whole material has the effect of the left end being fixed and the right end being stretched to the right. This process does work on the material, causing the material temperature to rise.

[0041] Specifically, the second cycle is an isothermal process, which is a heat release process. The material position is fixed and an isothermal and isobaric ensemble is used to return the material to room temperature of 300K. This simulates the process of contacting with a heat source in the experiment and releasing the heat generated by the material heating up, which is the process of heat discharge from the outdoor unit of an air conditioner in reality.

[0042] Specifically, the third cycle is a contraction process, which is an adiabatic process. Using an isobaric and isoenthalpic ensemble, the graphene kirigami configuration is contracted along the -x direction. That is, the velocity command is used to give the atoms on the right side of the material a velocity to the left, so that the right end of the material as a whole retracts to the left. In this process, the material does work externally, which reduces the material temperature.

[0043] Specifically, the fourth cycle is the process of absorbing heat, which is an isothermal process. The material position is fixed and an isothermal and isobaric ensemble is used to return the material to room temperature of 300K, simulating the process of contacting with the heat source in the experiment and absorbing the heat of the relatively high-temperature heat source, which is the process of indoor cooling by air conditioning in reality.

[0044] The above four processes constitute the refrigeration cycle of solid-state refrigerant materials, which are repeated to achieve the refrigeration effect.

[0045] Step 6: Simulate the heating process of the material from 200K to 400K, and calculate the change in the total energy of the material as the temperature rises. The slope can be approximated as the specific heat capacity of the graphene kirigami configuration. According to the shrinkage process, the temperature change of the graphene kirigami is 7.94 K, that is, adiabatic temperature change, and the specific heat capacity of the model is calculated to be 2266 J·kg -1 ·K -1 , while the specific heat capacity obtained experimentally is 700 J·kg -1 ·K -1 ; According to the proportional relationship, the adiabatic temperature change of the material can be corrected to 25 K. Through the Clausius Clapeyron equation, the specific heat capacity of the system, temperature change and other data, the isothermal entropy change of the material can be calculated to be 60 J·kg -1 ·K -1 , both of which are key parameters for judging the performance of solid-state refrigeration materials.

[0046] Step 7: Count the total energy changes during stretching and contraction, and subtract the two to get the input work W , defined by heat Get heat, where m It's quality. C p is the specific heat ΔT It is adiabatic temperature change; the cooling performance is calculated based on work and heat Therefore, the COP of the graphene kirigami configuration can reach 2.38.

[0047] Step 8: Use the deform command to stretch the material to both sides and calculate the stress and strain data. Due to the existence of out-of-plane flipping, the strain is less than 30% of the stretching amount, and the strain of the material is much smaller than that of graphene itself, fluctuating below 50Mpa.

[0048] Step 9: Calculate thermal conductivity based on nonequilibrium molecular dynamics.

[0049] Specifically, the graphene kirigami configuration is divided into 30 areas, and the slowest atoms in the two middle areas are exchanged with the fastest atoms in the two end areas to achieve the effect of fast atoms in the middle area and slow atoms in the two side areas. Macroscopically, the temperature in the middle area is high and the temperature in the two side areas is low, forming a temperature gradient for heat transfer. The heat transferred after the stable temperature gradient is formed is counted. The thermal conductivity of the calculated material is 62 W·m -1 ·K -1 .

[0050] Therefore, by adopting the above technical solution, based on molecular dynamics simulation, graphene kirigami structure design was carried out to calculate the key performance parameters of solid-state refrigeration of the material, adiabatic temperature change, isothermal entropy change, refrigeration efficiency, driving force, and thermal conductivity. A configuration with excellent comprehensive refrigeration performance was obtained, and then this new material was introduced into the field of solid-state refrigeration, which is of great help in promoting the practical application of solid-state refrigeration technology.

[0051] Therefore, reference Figure 8 As shown, in some embodiments of the present application, a system for applying a graphene kirigami configuration in solid-state refrigeration is also provided, and the method for applying a graphene kirigami configuration in solid-state refrigeration described above is adopted, including: The model design module 101 is used to design a graphene kirigami configuration; it is also used to design a cut graphene kirigami configuration to reduce the driving force through kirigami technology; construct a structural model and perform a hydrogenation operation on the structural model; wherein the hydrogenation operation includes: allowing an edge carbon atom to adsorb a hydrogen atom to ensure that adjacent edge carbon atoms do not produce covalent bonds during the stretching process; using modeling software to design multiple configurations and compare refrigeration performance parameters to screen and generate the optimal graphene kirigami configuration.

[0052] Refrigeration cycle module 102 is used to simulate the refrigeration cycle process: use molecular dynamics calculations to simulate the refrigeration cycle process of different graphene kirigami configurations to generate materials that can stably perform reversible refrigeration cycles; it is also used to select a preset potential function; set the simulation box to apply periodic boundary conditions along the y and z directions, set the x direction as the stretching direction and set the x direction as a fixed boundary; step S23: assign a velocity to each atom according to the Gaussian distribution so that the whole reaches the preset room temperature, and then use an isothermal and isobaric ensemble to relax the material at room temperature and pressure for the first preset time to stabilize the structure and converge parameters such as energy and force to the minimum value ; Step S24: Perform a stretching process: Use an isobaric and isoenthalpic ensemble to stretch the graphene paper-kirigami configuration along the x direction; Step S25: Perform a heat release process: Fix the material position and use an isothermal and isobaric ensemble to return the material to a preset room temperature to simulate the contact with the heat source in the experiment and release the heat generated by the material heating; Step S26: Perform a contraction process: Use an isobaric and isoenthalpic ensemble to contract the graphene paper-kirigami configuration along the x direction; Step S27: Perform a heat absorption process: Fix the material position and use an isothermal and isobaric ensemble to return the material to a preset room temperature to simulate the contact with the heat source in the experiment and absorb the heat from the relatively high temperature heat source.

[0053] The adiabatic temperature change module 103 is used for adiabatic temperature change testing: statistics are made on the adiabatic temperature changes of the graphene kirigami configuration during the stretching and contraction processes to obtain the adiabatic temperature change data of the material; it is also used to count the temperature changes during the stretching and contraction processes and calculate the average value of the temperature changes; the temperature within the statistical interval is calculated at intervals of a second preset time to generate temperature change curves for different processes; and the actual adiabatic temperature change of the material is calculated based on the heat capacity correction.

[0054] The isothermal entropy change module 104 is used for isothermal entropy change test: the material is heated and the specific heat capacity is calculated, and then the isothermal entropy change in the cooling process is calculated by the Clausius Clapeyron equation; it is also used to simulate the heating process: the temperature is raised from a first preset temperature to a second preset temperature, and the change in the total energy of the material with the increase in temperature is statistically calculated and the slope is set to the specific heat capacity of the graphene paper-kirigami configuration; according to the Clausius Clapeyron equation Calculate the isothermal entropy change, where C p is the specific heat capacity, ΔT is adiabatic temperature change, T It's the temperature.

[0055] Refrigeration test module 105 is used for refrigeration performance test: the total energy change of the graphene kirigami configuration during the stretching and contraction process is counted to generate input work, and heat is generated according to the temperature change and specific heat capacity through the heat definition, and the refrigeration performance is calculated according to the work and heat; it is also used to count the total energy change of the graphene kirigami configuration during the stretching and contraction process and subtract the two to obtain the input work W; Defined by heat Get heat, where m It's quality. C p is the specific heat ΔT It is adiabatic temperature change; the cooling performance is calculated based on work and heat .

[0056] The pressure test module 106 is used for driving pressure test: by stretching at both ends, outputting stress and strain curves, and obtaining driving pressures under different strains.

[0057] The thermal conductivity calculation module 107 is used to calculate the thermal conductivity through the temperature gradient of heat conduction according to the method of non-equilibrium molecular dynamics; and is also used to count the heat transmitted after forming a stable temperature gradient according to the method of non-equilibrium molecular dynamics: ; Calculate thermal conductivity.

[0058] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0059] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for applying graphene kirigami configuration in solid-state refrigeration, characterized in that: The following steps are involved: Step S1: designing a graphene kirigami configuration; Step S2: Simulating the refrigeration cycle process: using molecular dynamics calculations to simulate the refrigeration cycle process of different graphene kirigami configurations to generate materials that can stably perform a reversible refrigeration cycle; Step S3: Adiabatic temperature change test: statistically analyze the adiabatic temperature change of the graphene kirigami configuration during the stretching and contraction process to obtain the adiabatic temperature change data of the material; Step S4: Isothermal entropy change test: the material is heated and the specific heat capacity is calculated, and then the isothermal entropy change during the cooling process is calculated by the Clausius-Clapeyron equation; Step S5: Refrigeration performance test: Count the total energy change of the graphene kirigami configuration during the stretching and contraction process, obtain input work data, and calculate the heat according to the temperature change and specific heat capacity through the definition of heat, and calculate the refrigeration performance according to the work and heat; Step S6: driving pressure test: by stretching at both ends, outputting stress and strain curves, and obtaining driving pressures under different strains; Step S7: Calculate thermal conductivity through the temperature gradient of heat conduction according to the method of non-equilibrium molecular dynamics.

2. The method for applying graphene kirigami configuration in solid-state refrigeration according to claim 1, characterized in that: In step S1, the application further includes: Step S11: using the paper-cutting technology, designing a cut graphene paper-cut configuration to reduce the driving force; Step S12: constructing a structural model and performing a hydrogenation operation on the structural model; Step S13: Design a variety of configurations using modeling software and compare refrigeration performance parameters to screen and generate the optimal graphene paper-kirigami configuration.

3. The method for applying graphene kirigami configuration in solid-state refrigeration according to claim 1 or 2, characterized in that: In step S12, the hydrogenation operation includes: allowing the edge carbon atom to adsorb a hydrogen atom to ensure that covalent bonds are not generated between adjacent edge carbon atoms during the stretching process.

4. The application of graphene kirigami configuration in solid-state refrigeration according to claim 1 or 2, characterized in that: In step S2, the application further includes: Step S21: Select a preset potential function; Step S22: Set the simulation box to apply periodic boundary conditions along the y and z directions, set the x direction as the stretching direction and set the x direction as a fixed boundary.

5. The method for applying graphene kirigami configuration in solid-state refrigeration according to claim 4, characterized in that: In step S2, the simulation process further includes: Step S23: assigning a velocity to each atom according to Gaussian distribution, so that the whole reaches a preset room temperature, and then using an isothermal and isobaric ensemble to relax the material at room temperature and pressure for a first preset time, so that the structure is stable and parameters such as energy and force converge to a minimum value; Step S24: performing a stretching process: using an isobaric and isoenthalpic ensemble, stretching the graphene kirigami configuration along the x direction; Step S25: performing a heat release process: fixing the position of the material unchanged, using an isothermal and isobaric ensemble, returning the material to a preset room temperature, simulating contact with a heat source in the experiment, and releasing the heat generated by the material heating; Step S26: performing a contraction process: using an isobaric and isoenthalpic ensemble to contract the graphene kirigami configuration along the x direction; Step S27: Perform heat absorption process: fix the position of the material and use an isothermal and isobaric ensemble to return the material to a preset room temperature to simulate contact with the heat source in the experiment and absorb heat from a relatively high temperature heat source.

6. The method for applying graphene kirigami configuration in solid-state refrigeration according to claim 5, characterized in that: In step S3, the application further includes: Step S31: Counting the temperature changes during the stretching process and the shrinking process and calculating the average value of the temperature changes; Step S32: Counting the temperature within the second preset time interval to generate temperature change curves of different processes; Step S33: Calculate the actual adiabatic temperature change of the material based on the heat capacity correction.

7. The method for applying graphene kirigami configuration in solid-state refrigeration according to claim 1 or 6, characterized in that: In step S4, the application further includes: Step S41: simulating a heating process: raising the temperature from a first preset temperature to a second preset temperature, statistically analyzing the change in the total energy of the material as the temperature increases, and setting the slope as the specific heat capacity of the graphene kirigami configuration; Step S42: According to the Clausius-Clapeyron equation Calculate the isothermal entropy change, where C p is the specific heat capacity, Δ T is adiabatic temperature change, T It's the temperature.

8. The method for applying graphene kirigami configuration in solid-state refrigeration according to claim 7, characterized in that: In step S5, the application further includes: Step S51: Count the total energy change of the graphene kirigami configuration during the stretching and contraction process and subtract the two to obtain the input work W ; Step S52: Define by heat Get heat, where m It's quality. C p is the specific heat ΔT It is adiabatic temperature change; Step S53: Calculate refrigeration performance based on work done and heat .

9. The method for applying graphene kirigami configuration in solid-state refrigeration according to claim 1, characterized in that: In step S7, the application further includes: Step S71: According to the non-equilibrium molecular dynamics method, the heat transferred after forming a stable temperature gradient is counted: ; Step S72: Calculate thermal conductivity.

10. A system based on graphene kirigami configuration in solid-state refrigeration, using the method for applying graphene kirigami configuration in solid-state refrigeration according to any one of claims 1 to 9, characterized in that: include: Model design module, used to design graphene kirigami configurations; Refrigeration cycle module, used to simulate the refrigeration cycle process: using molecular dynamics calculations to simulate the refrigeration cycle process of different graphene kirigami configurations, to generate materials that can stably perform reversible refrigeration cycles; Adiabatic temperature change module, used for adiabatic temperature change test: statistically analyze the adiabatic temperature change of graphene kirigami configuration during stretching and contraction to obtain the adiabatic temperature change data of the material; Isothermal entropy change module, used for isothermal entropy change test: the material is heated and the specific heat capacity is calculated, and then the isothermal entropy change during the cooling process is calculated by the Clausius Clapeyron equation; Refrigeration test module, used for refrigeration performance test: statistics on the total energy change of the graphene kirigami configuration during the stretching and contraction process, obtain input work data, and calculate the heat according to the temperature change and specific heat capacity through the definition of heat, and calculate the refrigeration performance according to the work and heat; Pressure test module, used for driving pressure test: by stretching at both ends, outputting stress and strain curves, and obtaining driving pressure under different strains; The thermal conductivity calculation module is used to calculate the thermal conductivity through the temperature gradient of heat conduction according to the method of non-equilibrium molecular dynamics.

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