Five-element high-entropy spinel type oxide for isotope thermophotovoltaic system, coating paint and preparation method of five-element high-entropy spinel type oxide and coating paint

Abstract

The invention discloses a pentabasic high-entropy spinel oxide for an isotope thermophotovoltaic system, a coating and a preparation method of the pentabasic high-entropy spinel oxide. The five-element high-entropy spinel type oxide is (Cu < 0.2 > Mn < 0.2 > Fe < 0.2 > Cr < 0.2 > Ni < 0.2 >) < 3 > O < 4 >. The raw material of the coating paint comprises the five-membered high-entropy spinel oxide. The quinary high-entropy spinel oxide has excellent emission characteristics, so that the spectral intensity of thermal radiation emitted by a hot end is ensured, and more available photons can reach a photovoltaic module at the rear end; the high-entropy material has excellent high-temperature resistance and radiation resistance, and the stability of the high-entropy material in the isotope heat source surface high-temperature and high-radiation working environment can be guaranteed.

Description

Technical Field

[0001] The present application relates to the technical field of radioisotope thermophotovoltaic cells, and in particular to a five-element high-entropy spinel oxide and coating material and a preparation method for an isotope thermophotovoltaic system. Background Art

[0002] The isotope thermophotovoltaic system is a device that uses the heat generated by the decay energy of radioactive isotopes to heat the thermal radiator, which emits infrared light and further converts it into electrical energy with the help of a transducer photovoltaic unit array, thereby realizing the energy conversion process from decay energy → thermal energy → light energy → electrical energy. Compared with other isotope batteries / power sources, the isotope thermophotovoltaic system has unique advantages such as good transducer structure stability, high power density, and high theoretical energy conversion efficiency, and has the strength and potential to provide energy for deep space exploration.

[0003] However, considering the factor of radiation shielding, in isotope thermophotovoltaic systems, the surface of the isotope heat source is usually coated with a metal layer or ceramic oxide (Al2O3). However, due to the low infrared emissivity of the heat source coating material, its radiation characteristics are difficult to meet the requirements of isotope thermophotovoltaic. The commonly used thermal radiators, such as flat tungsten and rare earth element thermal radiators, also have poor output performance due to the low overall power density of the spectrum. The metamaterial / metasurface thermal radiators, which are currently being studied more, achieve precise control of the thermal radiation spectrum by designing a subwavelength-scale periodic structure on the surface. However, the preparation cost of this type of thermal radiator is high, the effective area that can be made is small, and the preparation process is quite complicated and easy to cause structural defects. In addition, the compatibility with the isotope heat source is poor, and the scalability is greatly limited. Summary of the invention

[0004] In order to solve the above-mentioned deficiencies in the art, the present application aims to provide a five-element high-entropy spinel oxide coating for isotope thermophotovoltaic system and a preparation method and application thereof.

[0005] According to one aspect of the present application, a five-element high entropy spinel oxide is provided, which is (Cu 0.2 Mn 0.2 Fe 0.2 Cr 0.2 Ni 0.2 )3O4.

[0006] According to another aspect of the present application, a coating material for an isotope thermophotovoltaic system is also provided, and the raw materials of the coating material include: the above-mentioned five-element high-entropy spinel-type oxide.

[0007] According to some embodiments of the present application, the raw materials of the coating further include: an auxiliary agent;

[0008] The auxiliary agent is selected from one or more of epoxy-modified silicone resin, xylene, terpineol, ethyl cellulose, inorganic silicate binder, etc.

[0009] According to the third aspect of the present application, a method for preparing the above-mentioned coating material for isotope thermophotovoltaic system comprises:

[0010] Preparation of the five-element high entropy spinel oxide:

[0011] The raw materials including CuO, MnO2, Fe2O3, Cr2O3, and NiO are ball-milled with anhydrous ethanol and zirconium oxide to obtain a slurry;

[0012] The slurry is sequentially dried, calcined, and ground to obtain a powder of a five-element high entropy spinel oxide;

[0013] The powder of the five-element high entropy spinel oxide is mixed and ground with an auxiliary agent to obtain a coating material for an isotope thermophotovoltaic system.

[0014] According to some embodiments of the present application, the metal atomic ratio of the raw materials CuO, MnO2, Fe2O3, Cr2O3 and NiO is 1:1:1:1:1.

[0015] According to some embodiments of the present application, the mass ratio of the raw materials CuO, MnO2, Fe2O3, Cr2O3, NiO to anhydrous ethanol and zirconium oxide is 1:(2-2.5):(3-4).

[0016] According to some embodiments of the present application, the drying temperature is 80-90° C. and the drying time is 12-16 hours.

[0017] According to some embodiments of the present application, the calcination temperature is 700-1000° C. for 5-7 hours;

[0018] According to some embodiments of the present application, the calcination temperature is 900°C.

[0019] According to some embodiments of the present application, the heating rate of calcination is 5° C. / min.

[0020] According to some embodiments of the present application, (Cu 0.2 Mn 0.2 Fe 0.2 Cr 0.2 Ni 0.2 )The mass ratio of 3O4 powder to epoxy modified silicone resin and xylene is 1:(2.1-2.5):(1.2-1.7).

[0021] According to some embodiments of the present application, (Cu 0.2 Mn 0.2 Fe 0.2 Cr0.2 Ni 0.2 The mass ratio of )3O4 powder to ethyl cellulose, pine alcohol and inorganic silicate binder is 1:(0.03-0.06):(0.52-0.72):(0.03-0.06).

[0022] According to a fourth aspect of the present application, there is provided a use of the above-mentioned coating material for isotope thermophotovoltaic system in the preparation of isotope thermophotovoltaic cells.

[0023] Optionally, the coating material of the present application is prepared by spin coating.

[0024] Compared with the prior art, this application has at least the following beneficial effects:

[0025] The present application provides a five-element high entropy spinel oxide, which is (Cu 0.2 Mn 0.2 Fe 0.2 Cr 0.2 Ni 0.2 )3O4, and a coating material for an isotope thermal photovoltaic system made of the five-element high-entropy spinel oxide. The five-element high-entropy spinel oxide of the present application has excellent emission characteristics, thereby ensuring the intensity of the thermal radiation spectrum emitted by the hot end, so that more available photons can reach the photovoltaic components at the back end; the high-entropy material has excellent high-temperature resistance and radiation resistance, which can ensure its stability in the high-temperature and high-radiation working environment of the isotope heat source surface.

[0026] The coating material for isotope thermophotovoltaic system made of the five-element high-entropy spinel oxide of the present application is prepared by a high-temperature solid-phase synthesis method, which has a simple process, low cost, and is suitable for large-scale industrial production.

[0027] The coating material of the present application can solve the problem that ordinary flat-plate thermal radiators are limited by the shape of the heat source and have poor binding properties with isotope heat sources; thanks to the high entropy effect after adding transition metal cations, and the multi-valence state of metal cations leading to the disordered occupation of tetrahedrons and octahedrons in the spinel phase, the band gap of the oxide is ultimately reduced, the probability of electron transition is increased, and the emission performance is improved, thereby maintaining a high overall spectral intensity, thereby improving the energy conversion efficiency and overall output power of the isotope thermal photovoltaic system; compared with commonly used flat-plate thermal radiators, the thermal radiation coating is not limited by the shape of the heat source, has a wide effective area, and has controllable structural dimensions, and is more suitable for photovoltaic unit arrays in isotope thermal photovoltaic systems; 3D printing can also be used to prepare the slurry into the required special configuration, and the size of the material band gap can be controlled by adjusting the type of transition metal elements, thereby further controlling thermal radiation.

[0028] The application of the coating material for isotope thermophotovoltaic system in the preparation of isotope thermophotovoltaic cells can reduce the overall volume of isotope thermophotovoltaic cells, which is more conducive to the miniaturization of cells. In addition, high entropy spinel oxide is used as the coating material, which has excellent emission performance and high temperature robustness. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a schematic diagram of the crystal structure of the five-element high-entropy spinel oxide of the present application.

[0030] Figure 2 Schematic diagram of the application of thermal radiation coating in isotope thermophotovoltaic system.

[0031] Figure 3 This is a process flow chart of preparing a thermal radiation coating by spin coating in an exemplary embodiment of the present application.

[0032] Figure 4 Schematic diagram (above) and actual picture (below) of the preparation of coating heat source in the exemplary embodiment of the present application.

[0033] Figure 5 The emission performance of the coating prepared using different organic solvents in the exemplary embodiments of the present application (left) and the adsorption effect on the surface of the ceramic heat source (right).

[0034] Figure 6 Comparison of cell output performance between a standard Al2O3 heat source (left) and a high entropy oxide coating heat source (right) in an example embodiment of the present application.

[0035] Figure 7 These are the XRD characterization results and emissivity test results of the five-element high entropy spinel oxide at different calcination temperatures in the exemplary embodiments of this application.

[0036] Figure 8 This is a SEM characterization image of the calcined pentacyclic high entropy spinel oxide in the exemplary embodiment of the present application.

[0037] Fig. 9 This is a comparison chart of the emissivity of the coating samples and the cold-pressed samples prepared in the exemplary embodiments and comparative examples of the present application.

[0038] Fig.10 This is an XRD characterization and emission performance test diagram of the coating sample after high temperature treatment and gamma ray irradiation in the exemplary embodiment of the present application. DETAILED DESCRIPTION

[0039] The technical solution of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0040] It is particularly important to point out that similar substitutions and modifications made to the present application are obvious to those skilled in the art, and they are all deemed to be included in the present application. Relevant personnel can obviously modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit and scope of the present application to implement and apply the technology of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments.

[0041] If no specific conditions are specified in this application, the preparation shall be carried out under conventional conditions or the conditions recommended by the manufacturer. The raw materials or excipients used, as well as the reagents or instruments used, for which the manufacturers are not specified, are all conventional products that can be obtained commercially.

[0042] The application is described in detail below.

[0043] Currently in isotope thermophotovoltaic systems, the overall emissivity of the heat source surface and commonly used thermal radiators is low, the combination of the thermal radiator and the isotope heat source is poor, the structural design of the thermal radiator is relatively complex, and the preparation process is complicated and costly.

[0044] The method of coating the heat source surface can greatly improve the intensity of the thermal radiation spectrum. This method has a relatively simple preparation process and can solve the problem of poor integration between the thermal radiator and the heat source. It is a simple, practical and effective method. However, the infrared emissivity of the heat source coating material is very low, and its radiation characteristics are difficult to meet the requirements of the isotope thermophotovoltaic system. The new high-emission material-high-entropy spinel oxide has excellent emission characteristics in the near-infrared band. At the same time, due to its spinel-type crystal structure, it also has good high temperature and radiation resistance. Therefore, for the high temperature and high radiation conditions of the isotope heat source surface, high-entropy spinel oxide can well meet the requirements of the heat source surface coating material.

[0045] Therefore, the present application proposes a thermal radiation coating which is suitable for an isotope heat source and has high emission characteristics and a simple preparation process.

[0046] The spinel material of the present application has a structural formula of AB2O4 and belongs to the cubic system (such as Figure 1As shown). Among them, the A ion forms a coordination structure with 4 oxygen ions and is located in the tetrahedral void, and the B ion forms a coordination structure with 6 oxygen atoms and is located in the octahedral void. In high-entropy spinel oxides, the elements at the A and B positions are usually transition metal elements, which makes this type of high-entropy oxide have many excellent physical or chemical properties. At the same time, by increasing the types of metal elements, this type of material also exhibits excellent thermal radiation performance.

[0047] Compared with other types and combinations of metal cations, this application selects five elements, Cu, Mn, Fe, Cr, and Ni, as metal cations at the A and B positions, which can greatly improve the emission performance and robustness of the material at high temperatures. At the same time, the coating material of this application has good bonding with the substrate and can be well coated on the surface of ceramics and Al2O3 substrates, such as Figure 2 The figure shows the application diagram of thermal radiation coating, where 1: thermal radiation coating; 2: 238 PuO2 heat source; 3: infrared radiation; 4: heat sink fins; 5: thermophotovoltaic unit.

[0048] The technical solution of the present application is further described below in conjunction with specific embodiments.

[0049] Example 1

[0050] Weigh CuO, MnO2, Fe2O3, Cr2O3, and NiO powders with equal metal atomic molar ratios and introduce them into a zirconia ball mill. Add an appropriate amount of anhydrous ethanol for wet ball milling, in which the oxide powder is mixed with anhydrous ethanol and zirconia grinding balls in a mass ratio of 1:2:3. Grind at 500r / min for 8h to obtain a uniform slurry. Subsequently, the uniform slurry is dried in a blast drying oven at 80°C for 12h, and a uniform precursor powder is formed after grinding. Pour the precursor powder into an alumina crucible, place it in a tubular furnace, keep it at 900°C for 5h, with a heating rate of 5°C / min, and cool to room temperature with the furnace. Grind the obtained sample in a mortar to obtain (Cu 0.2 Mn 0.2 Fe 0.2 Cr 0.2 Ni 0.2 )3O4 powder.

[0051] Cu 0.2 Mn 0.2 Fe 0.2 Cr 0.2 Ni 0.2 )3O4 powder, epoxy-modified silicone resin and xylene solvent were mixed in a mass ratio of 1:2.2:1.5 and ball-milled at a speed of 300 r / min for 5 h to obtain a uniform coating.

[0052] Example 2

[0053] Weigh CuO, MnO2, Fe2O3, Cr2O3, and NiO powders with equal metal atomic molar ratios and introduce them into a zirconia ball mill. Add an appropriate amount of anhydrous ethanol for wet ball milling, in which the oxide powder is mixed with anhydrous ethanol and zirconia grinding balls in a mass ratio of 1:2:3. Grind at 500r / min for 8h to obtain a uniform slurry. Subsequently, the uniform slurry is dried in a blast drying oven at 80°C for 12h, and a uniform precursor powder is formed after grinding. The precursor powder is poured into an alumina crucible, placed in a tubular furnace, and kept at 800°C for 5h with a heating rate of 5°C / min, and then cooled to room temperature with the furnace. The obtained sample is ground in a mortar to obtain (Cu 0.2 Mn 0.2 Fe 0.2 Cr 0.2 Ni 0.2 )3O4 powder.

[0054] Cu 0.2 Mn 0.2 Fe 0.2 Cr 0.2 Ni 0.2 )3O4 powder, epoxy-modified silicone resin and xylene solvent were mixed in a mass ratio of 1:2.2:1.5 and ball-milled at a speed of 300 r / min for 5 h to obtain a uniform coating.

[0055] Example 3

[0056] Weigh CuO, MnO2, Fe2O3, Cr2O3, and NiO powders with equal metal atomic molar ratios and introduce them into a zirconia ball mill. Add an appropriate amount of anhydrous ethanol for wet ball milling, in which the oxide powder is mixed with anhydrous ethanol and zirconia grinding balls in a mass ratio of 1:2:3. Grind at 500r / min for 8h to obtain a uniform slurry. Subsequently, the uniform slurry is dried in a blast drying oven at 80°C for 12h, and a uniform precursor powder is formed after grinding. Pour the precursor powder into an alumina crucible, place it in a tubular furnace, keep it at 700°C for 5h, with a heating rate of 5°C / min, and cool to room temperature with the furnace. Grind the obtained sample in a mortar to obtain (Cu 0.2 Mn 0.2 Fe 0.2 Cr 0.2 Ni 0.2 )3O4 powder.

[0057] Cu 0.2 Mn 0.2 Fe 0.2 Cr 0.2 Ni 0.2)3O4 powder, epoxy-modified silicone resin and xylene solvent were mixed in a mass ratio of 1:2.2:1.5 and ball-milled at a speed of 300 r / min for 5 h to obtain a uniform coating.

[0058] Example 4

[0059] Weigh CuO, MnO2, Fe2O3, Cr2O3, and NiO powders with equal metal atomic molar ratios and introduce them into a zirconia ball mill. Add an appropriate amount of anhydrous ethanol for wet ball milling, in which the oxide powder is mixed with anhydrous ethanol and zirconia grinding balls in a mass ratio of 1:2:3. Grind at 500r / min for 8h to obtain a uniform slurry. Subsequently, the uniform slurry is dried in a blast drying oven at 80°C for 12h, and a uniform precursor powder is formed after grinding. Pour the precursor powder into an alumina crucible, place it in a tubular furnace, keep it at 1000°C for 5h, with a heating rate of 5°C / min, and cool to room temperature with the furnace. Grind the obtained sample in a mortar to obtain (Cu 0.2 Mn 0.2 Fe 0.2 Cr 0.2 Ni 0.2 )3O4 powder.

[0060] Cu 0.2 Mn 0.2 Fe 0.2 Cr 0.2 Ni 0.2 )3O4 powder, epoxy-modified silicone resin and xylene solvent were mixed in a mass ratio of 1:2.2:1.5 and ball-milled at a speed of 300 r / min for 5 h to obtain a uniform coating.

[0061] Example 5

[0062] Weigh CuO, MnO2, Fe2O3, Cr2O3, and NiO powders with equal metal atomic molar ratios and introduce them into a zirconia ball mill. Add an appropriate amount of anhydrous ethanol for wet ball milling, in which the oxide powder is mixed with anhydrous ethanol and zirconia grinding balls in a mass ratio of 1:2.5:4. Grind at 500r / min for 8h to obtain a uniform slurry. Subsequently, the uniform slurry is dried in a blast drying oven at 80°C for 16h, and a uniform precursor powder is formed after grinding. Pour the precursor powder into an alumina crucible, place it in a tubular furnace, keep it at 900°C for 7h, with a heating rate of 8°C / min, and cool to room temperature with the furnace. Grind the obtained sample in a mortar to obtain (Cu 0.2 Mn 0.2 Fe 0.2 Cr 0.2 Ni 0.2 )3O4 powder.

[0063] Cu 0.2 Mn0.2 Fe 0.2 Cr 0.2 Ni 0.2 )3O4 powder, epoxy-modified silicone resin and xylene solvent were mixed in a mass ratio of 1:2.5:1.4 and ball-milled at a speed of 300 r / min for 5 h to obtain a uniform coating.

[0064] Example 6

[0065] Weigh CuO, MnO2, Fe2O3, Cr2O3, and NiO powders with equal metal atomic molar ratios and introduce them into a zirconia ball mill. Add an appropriate amount of anhydrous ethanol for wet ball milling, in which the oxide powder is mixed with anhydrous ethanol and zirconia grinding balls in a mass ratio of 1:2:3. Grind at 500r / min for 8h to obtain a uniform slurry. Subsequently, the uniform slurry is dried in a blast drying oven at 80°C for 12h, and a uniform precursor powder is formed after grinding. Pour the precursor powder into an alumina crucible, place it in a tubular furnace, keep it at 900°C for 5h, with a heating rate of 5°C / min, and cool to room temperature with the furnace. Grind the obtained sample in a mortar to obtain (Cu 0.2 Mn 0.2 Fe 0.2 Cr 0.2 Ni 0.2 )3O4 powder.

[0066] Cu 0.2 Mn 0.2 Fe 0.2 Cr 0.2 Ni 0.2 )3O4 powder, ethyl cellulose, pinene alcohol solvent and inorganic silicate binder were mixed in a mass ratio of 1:0.03:0.72:0.03, and a uniform coating was obtained after ball milling at a speed of 300 r / min for 5 h.

[0067] Example 7

[0068] Weigh CuO, MnO2, Fe2O3, Cr2O3, and NiO powders with equal metal atomic molar ratios and introduce them into a zirconia ball mill. Add an appropriate amount of anhydrous ethanol for wet ball milling, in which the oxide powder is mixed with anhydrous ethanol and zirconia grinding balls in a mass ratio of 1:2:3. Grind at 500r / min for 8h to obtain a uniform slurry. Subsequently, the uniform slurry is dried in a blast drying oven at 80°C for 12h, and a uniform precursor powder is formed after grinding. Pour the precursor powder into an alumina crucible, place it in a tubular furnace, keep it at 1000°C for 5h, with a heating rate of 5°C / min, and cool to room temperature with the furnace. Grind the obtained sample in a mortar to obtain (Cu 0.2 Mn 0.2 Fe 0.2 Cr 0.2 Ni0.2 )3O4 powder.

[0069] Cu 0.2 Mn 0.2 Fe 0.2 Cr 0.2 Ni 0.2 )3O4 powder, ethyl cellulose, pinene alcohol solvent and inorganic silicate binder were mixed in a mass ratio of 1:0.03:0.72:0.03, and a uniform coating was obtained after ball milling at a speed of 300 r / min for 5 h.

[0070] Comparative Example 1

[0071] The preparation steps are the same as those in Example 1, except that the oxide powder includes CuO, MnO2, Fe2O3, and Cr2O3.

[0072] Comparative Example 2

[0073] Traditional spinel oxide CuMn2O4 has excellent emission properties in the near-infrared, but its thermal radiation spectrum changes significantly after heat treatment at 500°C, so it is not suitable for isotope heat sources near 1000°C.

[0074] (Pr 0.5 Y 0.5 )CrO3,(Pr 0.3 Y 0.3 Ca 0.4 )CrO3,(Pr 0.3 Y 0.3 Ca 0.4 )(Cr 0.5 Co 0.5 )O3,(Pr 0.3 Y 0.3 Ca 0.4 )(Cr 0.5 Mn 0.5 )O3,(Pr 0.3 Y 0.3 Ca 0.4 )CrO3 and other high entropy spinel oxide coatings have lower near-infrared emissivity than the five-element (Cu 0.2 Mn 0.2 Fe 0.2 Cr 0.2 Ni 0.2 )3O4 coating.

[0075] The existing public technologies have not explored the service stability of the emission characteristics of high-entropy spinel oxides under ionizing radiation. Therefore, when it is applied to isotope heat sources, the heat source utilization rate and overall performance improvement effect will be lower than that of the present application.

[0076] Experimental example

[0077] 1. The coating materials prepared in the above embodiments and comparative examples were evenly coated on Al2O3 ceramic discs by spin coating. The spin-coated samples were dried in air at room temperature for 4 hours, and then annealed in an inert gas environment of a tube furnace at the corresponding sintering temperature for 2 hours to prepare the coating, and the following tests were performed:

[0078] Figure 5 The emission performance of the coating prepared using different organic solvents in the exemplary embodiment of this application (left) and the adsorption effect diagram on the surface of the ceramic heat source (right). In the figure, Alpha-Terpineol+Ethyl cellulose represents the solvent combination of terpineol and ethyl cellulose; Xylene+Epoxy resin represents the combination of xylene and epoxy resin.

[0079] Figure 6 Comparison of the battery output performance of the standard Al2O3 heat source in the exemplary embodiment of the present application (left) and the high entropy oxide coating heat source in Example 1 of the present application (right).

[0080] Figure 7 The characterization results of the five-element high entropy spinel oxide at different calcination temperatures (700°C, 800°C, 900°C, 1000°C) in the exemplary embodiment of this application are shown in Figure 1. Intensity (au) represents the XRD diffraction peak intensity, 2Theta (degree) represents the test angle range, and Emissivity represents the emissivity of the sample.

[0081] Figure 8 This is a SEM characterization image of the calcined pentacyclic high entropy spinel oxide in Example 1 of the present application.

[0082] from Figure 5 It can be seen that the organic solvent is basically removed after high-temperature annealing, so the impact on the emission performance is small. At the same time, compared with the solvent combination of epoxy resin and xylene, the adsorption effect of the coating prepared by adding pinene alcohol and ethyl cellulose is significantly improved.

[0083] from Figure 6 It can be seen that the electrical output performance has been greatly improved after coating modification, mainly reflected in the short-circuit current I sc There is a significant improvement, and the output power at the same temperature is increased by more than 50% compared to before coating.

[0084] from Figure 7It can be seen that the prepared samples have formed a good spinel phase. The higher the calcination temperature, the narrower the diffraction peak width becomes, the stronger the peak intensity becomes, and the peak position tends to shift slightly to the left, indicating that the crystallinity has increased. However, from the emissivity test results, it can be seen that the difference in emissivity at different calcination temperatures is not obvious, indicating that the effect of powder crystallinity on the emissivity of the coating is small. The emission properties of the samples calcined at 900℃ and 1000℃ are basically the same, while the emission properties of the samples calcined at 700℃ are relatively poor, indicating that there is a residual oxide phase that has not reacted at 700℃.

[0085] from Figure 8 It can be seen that after the high-temperature solid-phase reaction, the grains exhibit a polyhedral structure, and smooth crystal faces and distinguishable grain boundaries can be seen, which corresponds to the tetrahedron and octahedron structure in the spinel structure, indicating that the prepared material meets the definition of high-entropy spinel oxide materials.

[0086] 2. Compare the emission performance of thermal radiators prepared by spin coating and cold pressing.

[0087] like Fig. 9 The figure shows the emissivity comparison between the spin coating sample and the cold pressing coating sample. In the figure, QE represents the external quantum efficiency of the transducer photovoltaic unit.

[0088] according to Fig. 9 It can be seen that compared with the samples prepared by cold pressing, the coating prepared by the spin coating process has a higher infrared emissivity. Therefore, for the isotope heat source, compared with the bulk thermal radiator, the coating can better improve the utilization rate of the heat source and thus achieve a higher thermal radiation spectrum intensity, so that more photons can reach the rear-end transducer photovoltaic unit array, thereby improving the overall electrical performance of the isotope thermal photovoltaic system.

[0089] according to Fig.10 It can be seen that after 1400K high temperature heat treatment for 30h and irradiation treatment, (Cu 0.2 Mn 0.2 Fe 0.2 Cr 0.2 Ni 0.2 )3O4 coating has not changed its physical phase. After heat treatment, the emissivity decreases by less than 1% in the wavelength range of 400-1800nm. After irradiation with a γ-equivalent irradiation dose of 74kGy, the emission spectrum of the coating has not changed substantially, indicating that the prepared (Cu 0.2 Mn 0.2 Fe 0.2 Cr 0.2 Ni 0.2 )3O4 coating has excellent high temperature robustness and radiation resistance.

[0090] The description of the above embodiments is only used to help understand the method and core idea of ​​the present application. It should be noted that, for ordinary technicians in this technical field, several improvements and modifications can be made to the present application without departing from the principles of the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

Claims

1. A five-element high entropy spinel oxide, characterized in that: Cu 0.2 Mn 0.2 Fe 0.2 Cr 0.2 Ni 0.2 )3O4.

2. A coating material for an isotope thermophotovoltaic system, characterized in that: The raw materials of the coating material include: the five-element high-entropy spinel oxide described in claim 1.

3. The coating material for isotope thermophotovoltaic system according to claim 2, characterized in that: The raw materials of the coating also include: auxiliary agents; The auxiliary agent is selected from one or more of epoxy-modified silicone resin, xylene, ethyl cellulose, pinene alcohol, and inorganic silicate binder.

4. A method for preparing a coating material for an isotope thermophotovoltaic system according to claim 3, characterized in that: include: Preparation of the five-element high entropy spinel oxide: The raw materials including CuO, MnO2, Fe2O3, Cr2O3, and NiO are ball-milled with anhydrous ethanol and zirconium oxide to obtain a slurry; The slurry is sequentially dried, calcined, and ground to obtain the powder of the pentacyclic high entropy spinel oxide; The powder of the five-element high-entropy spinel oxide is mixed and ground with an auxiliary agent to obtain the coating material for the isotope thermophotovoltaic system.

5. The preparation method according to claim 4, characterized in that: The mass ratio of the raw material to the anhydrous ethanol and the zirconium oxide is 1:(2-2.5):(3-4).

6. The preparation method according to claim 4, characterized in that: The drying temperature is 80-90°C and the drying time is 12-16 hours.

7. The preparation method according to claim 4, characterized in that: The calcination temperature is 700-1000°C for 5-7h; 900°C is optional.

8. The preparation method according to claim 4, characterized in that: The heating rate of the calcination is 5-10°C / min.

9. The preparation method according to any one of claims 4 to 8, characterized in that: The mass ratio of the powder of the five-element high entropy spinel oxide to the epoxy-modified silicone resin and xylene is 1:(2.1-2.5):(1.2-1.7); The mass ratio of the powder of the five-element high entropy spinel oxide to ethyl cellulose, pine alcohol and inorganic silicate binder is 1: (0.03-0.06): (0.52-0.72): (0.03-0.06).

10. An isotope thermophotovoltaic system coating material according to claim 2 or 3, and / or use of an isotope thermophotovoltaic system coating material prepared by the preparation method according to any one of claims 4 to 9 in preparing an isotope thermophotovoltaic system; Optionally, the isotope thermophotovoltaic system coating material is prepared into an isotope thermophotovoltaic system coating by a spin coating method.

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