A shape memory alloy driven dual-mode thermal management film and a preparation method thereof
By using a dual-mode thermal management film driven by shape memory alloys, the problem of overcooling of passive daytime radiative cooling materials in cold seasons is solved, achieving year-round zero-energy adaptive thermal management and reducing building energy consumption and carbon emissions.
Patent Information
- Application Number
- CN202511941841.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-22
- Publication Date
- 2026-06-26
AI Technical Summary
Existing passive daytime radiant cooling materials continue to radiate heat to the outside during cold or transitional seasons, leading to 'overcooling', increasing heating energy consumption, and failing to adapt to fluctuating climates throughout the year. Furthermore, existing solutions suffer from system complexity, low reliability, and high maintenance costs.
The dual-mode thermal management film driven by shape memory alloy has a three-layer asymmetric structure, including a radiation cooling functional layer, a shape memory driving layer, and a solar energy absorption functional layer. It achieves zero-energy autonomous adjustment through the deformation switching mode of the nickel-titanium alloy sheet. The film automatically switches between cooling and heating modes within the range of 25℃ to 35℃.
It achieves adaptive thermal management with zero energy consumption throughout the year, reducing HVAC energy consumption by 20% to 40%. The membrane cools down by 5°C to 15°C or heats up by 8°C to 20°C in hot environments, has a long lifespan, and meets the requirement of 15 years of maintenance-free outdoor use.
Smart Images
Figure CN122281383A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of building energy conservation and thermal management materials technology, specifically relating to a dual-mode adaptive intelligent thermal management film with shape memory alloy as the driving element, which can autonomously switch between radiative cooling mode and solar heating mode according to ambient temperature, and its preparation method. Background Technology
[0002] Against the backdrop of a global move towards carbon neutrality, building operating energy consumption now accounts for over 30% of total societal energy consumption, with heating, ventilation, and air conditioning (HVAC) systems making a particularly significant contribution to carbon emissions. Passive daytime radiant cooling (PDRC) materials radiate heat into outer space through 8–13 μm atmospheric transparent windows, achieving daytime cooling under zero-energy conditions, and have become a research hotspot for reducing building cooling loads. However, the infrared emissivity of existing PDRC materials is not adjustable once formed, and they continue to radiate heat into the outside world during cold or transitional seasons, causing an "overcooling" phenomenon that actually increases heating energy consumption. This "one-way cooling" characteristic makes PDRC unable to adapt to fluctuating climates throughout the year, limiting its large-scale application.
[0003] To achieve dual-mode switching between cooling and heating, existing solutions have attempted to introduce external energy inputs such as electric drive, mechanical drive, or solution circulation. However, these solutions all suffer from drawbacks such as system complexity, low reliability, and high maintenance costs, making them difficult to integrate with the building facade. Therefore, developing an intelligent thermal management film that requires no external energy, can autonomously sense ambient temperature, and quickly switch operating modes has become an urgent need in the field of building energy conservation. Summary of the Invention
[0004] The technical objective of this invention is to address the above-mentioned shortcomings by providing a shape memory alloy-driven dual-mode thermal management thin film and its preparation method, thereby resolving the aforementioned technical problems.
[0005] This invention provides a shape memory alloy-driven dual-mode thermal management thin film, wherein: the thin film is a three-layer asymmetric stacked structure consisting of a "radiative cooling functional layer / shape memory driving layer / solar energy absorption functional layer"; the shape memory driving layer is composed of a nickel-titanium alloy sheet with a two-way shape memory effect, and its phase transition critical temperature Tc is 25 ℃~35 ℃; when the ambient temperature ≥ Tc, the nickel-titanium alloy sheet is flattened with the radiative cooling functional layer facing outwards, and the thin film operates in radiative cooling mode; when the ambient temperature < Tc, the nickel-titanium alloy sheet automatically curls up with the solar energy absorption functional layer facing outwards, and the thin film operates in solar heating mode; the mode switching does not require external energy or manual intervention.
[0006] Preferably, the nickel-titanium alloy sheet has a thickness of 0.1 mm to 0.3 mm and is rapidly cooled after being annealed at 400 ℃ to 500 ℃ in a vacuum or inert atmosphere for 10 min to 30 min to establish the two-way shape memory effect.
[0007] Preferably, the radiative cooling functional layer is formed by coating and curing a composite slurry of "matrix resin-multi-scale hollow microspheres-functional filler"; the multi-scale hollow microspheres are selected from at least two of hollow SiO2, ZnO, PMMA, PS, HGBs, SiO2 / Al2O3, SiO2 / ZnO, and SiO2 / TiO2 microspheres, with a particle size of 0.5 μm to 30 μm and a shell thickness of 10 nm to 1000 nm; the slurry composition is: 20% to 45% hollow microspheres, 20% to 50% matrix resin, 5% to 10% functional filler, and 1% to 10% additives.
[0008] Preferably, the matrix resin is selected from at least one of water-based or oil-based polyacrylate, polyurethane, polyvinyl alcohol, epoxy resin, PDMS, PMMA, PVDF, PTFE, polycarbonate, or silicone resin; the functional filler is selected from at least one of SiO2, Al2O3, BN, TiO2, and BaSO4; and the additive is selected from at least one of diluent, dispersant, leveling agent, and curing agent.
[0009] Preferably, the radiative cooling functional layer has a solar reflectivity ≥ 0.94 in the 0.3 μm to 2.5 μm band and an average infrared emissivity ≥ 0.95 in the 8 μm to 13 μm atmospheric window.
[0010] Preferably, the solar energy absorption functional layer is formed by sequentially forming a graphite film and a Ti3C2 MXene nanosheet film on the other side of a nickel-titanium alloy sheet; the graphite film is formed by spraying graphite sheets with a particle size of 1μm to 10 μm and a thickness of 1μm to 10 μm; the Ti3C2 MXene nanosheet film is formed by drop-coating or spin-coating a single layer or a few layers of MXene aqueous dispersion and drying.
[0011] Preferably, the solar energy absorption functional layer has an absorption rate of ≥0.88 for sunlight in the range of 0.3 μm to 2.5 μm, and an average infrared emissivity of ≤0.28 in the atmospheric window of 8 μm to 13 μm.
[0012] Preferably, the solar energy absorption functional layer can raise the surface temperature of the film by 8°C to 20°C under direct sunlight at noon; the radiation cooling functional layer can lower the surface temperature of the film by 5°C to 15°C under direct sunlight at noon.
[0013] Preferably, the phase transition critical temperature Tc of the shape memory driving layer is precisely set by adjusting the Ni / Ti atomic ratio and / or introducing trace amounts of a third component.
[0014] Preferably, wherein: (a) The nickel-titanium alloy sheet is laser-cut or punched and ultrasonically cleaned, then annealed at a temperature of 400℃~500℃, and then rapidly cooled to room temperature to pre-deform it into a flat substrate. (b) A multi-scale hollow microsphere composite slurry is coated and cured on the front side of the substrate to form a radiation cooling functional layer; (c) A graphite dispersion is sequentially sprayed onto the reverse side of the substrate and dried. Plasma is used to modify the surface. A Ti3C2MXene dispersion is then coated and dried to form a solar energy absorption functional layer. (d) The resulting three-layer asymmetric thin film can achieve the zero-energy, all-season, adaptive dual-mode thermal management under natural environment.
[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. Zero energy consumption and highly sensitive adaptive characteristics: The shape memory alloy sheet can generate reversible flattening-rolling deformation within a narrow temperature range of 25 ℃–35 ℃, directly driving the thin film to switch between "radiative cooling and solar heating" without the need for external power supply, sensors or mechanical transmission components, and the energy consumption is zero throughout the year; the graphite / MXene photothermal layer can preheat the alloy sheet, reducing the operating temperature by 2–4 ℃ and increasing the response speed by more than 30%.
[0016] 2. Extreme spectral performance with wide-range thermal modulation: the radiative cooling layer has a reflectivity ≥ 0.94 at 0.3 μm–2.5 μm and an emissivity ≥ 0.95 at 8 μm–13 μm; the solar absorption layer has a solar absorptivity ≥ 0.88 and an emissivity ≤ 0.28 at the same infrared window. This allows the same thin film to achieve extreme spectral performance of "high reflectivity-high emissivity" cooling and "high absorption-low emissivity" heating. Under direct sunlight at noon, the surface temperature can be reduced by 5 ℃–15 ℃ or increased by 8 ℃–20 ℃, reducing HVAC energy consumption by 20%–40% throughout the year.
[0017] 3. Thin-film construction with a long service life; total thickness 0.2 mm–0.6 mm, areal density <500 g / m²; can be continuously prepared through roll coating, spraying, or scraping; can be integrated with building roofs, agricultural greenhouses, and other enclosure structures in a single adhesive / magnetic bonding process; NiTi alloy double-cycle memory life >10 4After 500 hours of UV aging, the performance of the spectral coating decreases by less than 5%, meeting the requirement of 15 years of maintenance-free outdoor use. Attached Figure Description
[0018] Figure 1 This is a cross-sectional scanning electron microscope image of a multi-scale hollow microsphere gradient composite film.
[0019] Figure 2 Scanning electron microscope (SEM) image of a composite film of graphite sheets and Ti3C2 MXene nanosheets (G / MXene).
[0020] Figure 3 The solar reflectance spectrum and long-wave infrared emissivity spectrum are shown.
[0021] Figure 4 This is the outdoor temperature curve.
[0022] Figure 5 This is a schematic diagram for architectural applications. Detailed Implementation
[0023] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.
[0024] The present invention will be further described below with reference to specific embodiments and accompanying drawings, but the present invention is not limited to the following embodiments. Unless otherwise specified, the methods described are conventional methods. Unless otherwise specified, the raw materials are all available from publicly available commercial sources.
[0025] This invention provides a shape memory alloy-driven dual-mode thermal management film, wherein: the film is a three-layer asymmetric stacked structure consisting of a "radiative cooling functional layer / shape memory driving layer / solar energy absorption functional layer"; the shape memory driving layer is composed of a nickel-titanium alloy sheet with a two-way shape memory effect, and its phase transition critical temperature Tc is 25℃~35℃; when the ambient temperature ≥ Tc, the nickel-titanium alloy sheet is flattened with the radiative cooling functional layer facing outwards, and the film operates in radiative cooling mode; when the ambient temperature < Tc, the nickel-titanium alloy sheet automatically curls up with the solar energy absorption functional layer facing outwards, and the film operates in solar heating mode; the mode switching requires no external energy or manual intervention. This technical solution enables the film to autonomously switch between "cooling" and "heating" operating modes according to the ambient temperature, solving the problems of traditional PDRC (Physical Dependent Refrigerator) being too cold in winter and requiring external drive, achieving year-round zero-energy thermal management.
[0026] In a preferred embodiment, the nickel-titanium alloy sheet has a thickness of 0.1 mm to 0.3 mm and is rapidly cooled after vacuum or inert atmosphere annealing at 400°C to 500°C for 10 to 30 minutes to establish the two-way shape memory effect. This technical solution enables the alloy sheet to output a driving force of >200 MPa within a narrow temperature range of 25°C to 35°C, with a cycle life >10. 4 This ensures reliable deformation of the film for more than 10 years.
[0027] In a preferred embodiment, the radiative cooling functional layer is formed by coating and curing a composite slurry of "matrix resin-multi-scale hollow microspheres-functional fillers"; the multi-scale hollow microspheres are selected from at least two of hollow SiO2, ZnO, PMMA, PS, HGBs, SiO2 / Al2O3, SiO2 / ZnO, and SiO2 / TiO2 microspheres, with a particle size of 0.5μm to 30μm and a shell thickness of 10nm to 1000nm; the slurry composition is: 20% to 45% hollow microspheres, 20% to 50% matrix resin, 5% to 10% functional fillers, and 1% to 10% additives. This technical solution enables the coating to achieve a reflectivity ≥0.94 at 0.3μm–2.5μm and an emissivity ≥0.95 at 8μm–13μm, and can reduce the temperature by 5℃–15℃ at noon, solving the problem of overheating in high solar irradiance areas during summer.
[0028] In a preferred embodiment, the matrix resin is selected from at least one of water-based or oil-based polyacrylate, polyurethane, polyvinyl alcohol, epoxy resin, PDMS, PMMA, PVDF, PTFE, polycarbonate, or silicone resin; the functional filler is selected from at least one of SiO2, Al2O3, BN, TiO2, and BaSO4; and the additives are selected from at least one of diluent, dispersant, leveling agent, and curing agent. The above technical solution makes the slurry compatible with commonly used roll-type building materials processes, allowing for continuous scraping and spraying, with a width ≥1.5m and a production speed >5m / min, meeting the needs of large-scale production.
[0029] In a preferred embodiment, the radiative cooling functional layer has a solar reflectivity ≥0.94 in the 0.3μm–2.5μm wavelength band and an average infrared emissivity ≥0.95 in the 8μm–13μm atmospheric window. This technical solution enables the thin film to radiate excess heat to outer space through the atmospheric window in hot environments, reducing the roof surface temperature and alleviating the air conditioning load.
[0030] In a preferred embodiment, the solar energy absorption functional layer is formed by sequentially forming a graphite film and a Ti3C2MXene nanosheet film on the other side of a nickel-titanium alloy sheet. The graphite film is formed by spraying graphite sheets with a particle size of 1μm to 10μm and a thickness of 1μm to 10μm. The Ti3C2MXene nanosheet film is formed by drop-coating or spin-coating a single layer or a few layers of MXene aqueous dispersion and then drying. This technical solution results in a solar absorptivity ≥0.88 and an infrared emissivity ≤0.28 for the absorption layer, and can raise the temperature by 8℃–20℃ at noon, solving the problem of high energy consumption for heating in cold regions during winter.
[0031] In a preferred embodiment, the solar energy absorption functional layer has an absorption rate of ≥0.88 for sunlight in the 0.3μm–2.5μm range, and an average infrared emissivity of ≤0.28 within the 8μm–13μm atmospheric window. This technical solution enables the thin film to efficiently capture solar radiation and suppress its own thermal radiation under low-temperature conditions, achieving passive heating and reducing the need for additional heating.
[0032] In a preferred embodiment, the solar energy absorption layer can raise the surface temperature of the film by 8°C to 20°C under direct midday sunlight; the radiative cooling layer can lower the surface temperature of the film by 5°C to 15°C under direct midday sunlight. This technical solution allows a single film to cover both summer and winter extreme conditions, reducing HVAC energy consumption by 20%–40% annually and significantly lowering building carbon emissions.
[0033] In a preferred embodiment, the phase transition critical temperature Tc of the shape memory driving layer is precisely set by adjusting the Ni / Ti atomic ratio and / or introducing trace amounts of a third component. This technical solution allows for batch customization of various Tc specifications, such as 25℃, 28℃, 32℃, and 35℃, on the same production line to meet the application needs of different climate zones.
[0034] In a preferred embodiment, (a) a nickel-titanium alloy sheet is laser-cut or punched, ultrasonically cleaned, annealed at 400 ℃~500 ℃, and then rapidly cooled to room temperature to pre-deform it into a flat substrate; (b) a multi-scale hollow microsphere composite slurry is coated and cured on the front side of the substrate to form a radiation cooling functional layer; (c) a graphite dispersion is sequentially sprayed onto the back side of the substrate and dried, plasma is used to modify the surface, a Ti3C2 MXene dispersion is coated and dried to form a solar energy absorption functional layer; (d) the resulting three-layer asymmetric film can achieve the zero-energy consumption, all-season, adaptive dual-mode thermal management under natural conditions. The above technical solution allows the entire preparation process to be completed on a conventional coating production line with a width of 1.5m, a linear speed of 5m / min, a daily production capacity of >10000m², and a finished product thickness of 0.2mm–0.6mm. It can be directly transported in rolls, glued on-site, or magnetically installed, achieving "ready to use".
[0035] See attached document Figure 1-5 Provided as Example 1: (1) Pretreatment of the shape memory driving layer: A commercially available two-way shape memory effect nickel-titanium alloy sheet with a phase transition critical temperature of 30°C and a thickness of 0.2 mm was selected. It was laser-cut into a 100 mm × 100 mm square sheet. The alloy sheet was ultrasonically cleaned for 15 minutes each with acetone, anhydrous ethanol and deionized water to thoroughly remove surface contaminants, and then dried with nitrogen. The cleaned alloy sheet was placed in a tube furnace and annealed at 450°C for 20 minutes under argon protection, followed by rapid water quenching to room temperature. This heat treatment process aims to optimize the microstructure of the alloy and obtain excellent two-way shape memory effect. After heat treatment, the alloy sheet was pre-deformed at room temperature (about 25°C, below the phase transition temperature) to keep it completely flat as the substrate for subsequent coating.
[0036] (2) Preparation of the radiation cooling functional layer: 35 wt% polydimethylsiloxane (PDMS) was weighed as the matrix resin, 40 wt% multi-scale hollow silica (SiO2) microspheres (particle size range: 0.5-2 μm 15%, 2-10 μm 15%, 10-25 μm 10%) were weighed as the functional filler, and 24.5 wt% n-hexane was used as the diluent. The above raw materials were placed in a planetary mixer and stirred at 1500 rpm for 45 minutes to form a uniform, viscous white slurry. The slurry was uniformly coated onto the front side of the pretreated nickel-titanium alloy sheet using a scraper coating method. The scraper gap was controlled to ensure a wet film thickness of approximately 300 μm. The coated sample was then cured in an oven at 80°C for 2 hours. During the curing process, due to solvent evaporation and the movement of microspheres of different sizes within the resin system, hollow SiO2 microspheres spontaneously form a gradient distribution structure with particle size increasing from the surface to the bottom layer. After curing, they are naturally cooled to room temperature, forming a radiation-cooling functional layer with a thickness of approximately 200 μm.
[0037] (3) Preparation of the solar energy absorption functional layer: Graphite sheets (particle size 1-5 μm) were dispersed in ethanol to prepare a dispersion with a concentration of 10 mg / mL. The dispersion was uniformly sprayed onto the reverse side of the nickel-titanium alloy sheet (i.e., the side opposite to the radiation cooling functional layer) using a spraying device. After natural drying at room temperature for 3 hours, a dense graphite film was formed. The surface of the graphite film was treated with oxygen plasma for 2 minutes at a power of 100W to improve its hydrophilicity and surface energy. An aqueous dispersion of few-layer Ti3C2 MXene nanosheets (concentration 5 mg / mL) was taken and coated onto the surface of the plasma-treated graphite film using a spin coating method (2000 rpm, 30 seconds). Finally, the sample was placed in an 80°C oven and dried for 1 hour to form the final G / MXene composite solar energy absorption functional layer.
[0038] like Figure 1 As shown, hollow SiO2 microspheres of different sizes form a distinct gradient distribution structure in the PDMS matrix. This structure is key to achieving efficient broadband sunlight scattering and reflection.
[0039] like Figure 2 As shown, graphite sheets and MXene nanosheets form a closely packed, multi-level structure, constituting a highly efficient light-harvesting layer while ensuring low infrared emissivity.
[0040] Figure 3 The spectral data provide a direct comparison of the high reflectance and high emissivity of the radiative cooling functional layer and the high absorption and low emissivity of the solar absorption functional layer. The radiative cooling functional layer exhibits a high solar reflectance of 0.96 in the 0.3–2.5 μm wavelength range and an average emissivity of 0.96 in the 8–13 μm atmospheric window. In contrast, the solar absorption functional layer has an absorption rate of 0.90 and an average emissivity as low as 0.25 in the 8–13 μm wavelength range.
[0041] like Figure 4 As shown, the radiative cooling functional layer faces the sky, and the surface temperature of the thin film is reduced by approximately 9°C compared to the ambient air temperature, effectively achieving daytime radiative cooling. The solar absorption functional layer, i.e., the heating functional layer, faces the sky. The surface temperature of the thin film can rise to a maximum of 15°C under sunlight, exhibiting excellent photothermal heating performance.
[0042] Figure 5 The invention demonstrates the application of the film to building roofs or exterior walls. In the high temperatures of summer, the film is flattened for cooling (cooling mode); in the low temperatures of winter, the film is rolled up for heating (heating mode), revealing its "all-season, adaptive, zero-energy" thermal management capabilities.
[0043] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.
Claims
1. A shape memory alloy-driven dual-mode thermal management thin film, characterized in that: The thin film has an asymmetric stacked structure consisting of three layers: a radiation cooling functional layer, a shape memory driving layer, and a solar energy absorption functional layer. The shape memory driving layer is composed of a nickel-titanium alloy sheet with a two-way shape memory effect, and its phase transformation critical temperature Tc is 25 ℃~35 ℃; When the ambient temperature is ≥ Tc, the nickel-titanium alloy sheet is flattened with the radiative cooling functional layer facing outwards, and the thin film operates in radiative cooling mode. When the ambient temperature is < Tc, the nickel-titanium alloy sheet automatically curls up with the solar energy absorption functional layer facing outwards, and the thin film operates in solar heating mode. The mode switching requires no external energy or human intervention.
2. The thermal management film according to claim 1, characterized in that: The nickel-titanium alloy sheet has a thickness of 0.1 mm to 0.3 mm and is rapidly cooled after being annealed at 400 ℃ to 500 ℃ in a vacuum or inert atmosphere for 10 min to 30 min to establish the two-way shape memory effect.
3. The thermal management film according to claim 1 or 2, wherein: The radiative cooling functional layer is formed by coating and curing a composite slurry containing a matrix resin, multi-scale hollow microspheres, and functional fillers. The multi-scale hollow microspheres are selected from at least two of hollow SiO2, ZnO, PMMA, PS, HGBs, SiO2 / Al2O3, SiO2 / ZnO, and SiO2 / TiO2 microspheres, with a particle size of 0.5 μm to 30 μm and a shell thickness of 10 nm to 1000 nm. The composite slurry has the following mass composition: 20% to 45% hollow microspheres, 20% to 50% matrix resin, 5% to 10% functional fillers, and 1% to 10% additives.
4. The thermal management film according to claim 3, wherein: The matrix resin is selected from at least one of water-based or oil-based polyacrylate, polyurethane, polyvinyl alcohol, epoxy resin, PDMS, PMMA, PVDF, PTFE, polycarbonate, or silicone resin; the functional filler is selected from at least one of SiO2, Al2O3, BN, TiO2, and BaSO4; and the additives are selected from at least one of diluent, dispersant, leveling agent, and curing agent.
5. The thermal management film according to claim 3 or 4, wherein: The radiation cooling functional layer has a solar reflectivity ≥ 0.94 in the 0.3 μm to 2.5 μm band and an average infrared emissivity ≥ 0.95 in the 8 μm to 13 μm atmospheric window.
6. The thermal management film according to any one of claims 1-5, wherein: The solar energy absorption functional layer is formed by sequentially forming a graphite film and a Ti3C2 MXene nanosheet film on the other side of a nickel-titanium alloy sheet; the graphite film is formed by spraying graphite sheets with a particle size of 1 μm to 10 μm and a thickness of 1 μm to 10 μm; the Ti3C2 MXene nanosheet film is formed by drop-coating or spin-coating a single layer or few layers of MXene aqueous dispersion and then drying.
7. The thermal management film according to claim 6, wherein: The solar energy absorption functional layer has an absorption rate of ≥ 0.88 for sunlight in the range of 0.3 μm to 2.5 μm, and an average infrared emissivity of ≤ 0.28 in the atmospheric window of 8 μm to 13 μm.
8. The thermal management film according to any one of claims 1-7, wherein: The solar energy absorption layer can raise the surface temperature of the film by 8°C to 20°C under direct sunlight at noon; the radiation cooling layer can lower the surface temperature of the film by 5°C to 15°C under direct sunlight at noon.
9. The thermal management film according to any one of claims 1-8, wherein: The phase transition critical temperature Tc of the shape memory driving layer is set by adjusting the Ni / Ti atomic ratio and / or introducing trace amounts of a third component.
10. A method for preparing a thermal management thin film as described in any one of claims 1-9, characterized in that... In order, they include: (a) The nickel-titanium alloy sheet is laser-cut or punched and ultrasonically cleaned, then annealed at a temperature of 400 ℃~500 ℃, and then rapidly cooled to room temperature to pre-deform it into a flat substrate. (b) A multi-scale hollow microsphere composite slurry is coated and cured on the front side of the substrate to form a radiation cooling functional layer; (c) A graphite dispersion was sequentially sprayed onto the reverse side of the substrate and dried. Plasma was used to modify the surface. A Ti3C2MXene dispersion was then coated and dried to form a solar energy absorption functional layer. (d) The resulting three-layer asymmetric thin film can achieve the zero-energy, all-season, adaptive dual-mode thermal management under natural environment.