Radiation refrigeration-solar photo-thermal dynamic regulation and control device based on reversible metal electrodeposition

Abstract

The invention relates to a radiation refrigeration-solar photo-thermal dynamic regulation and control device based on reversible metal electrodeposition. A micro-nano structure conducting layer of a working electrode is composed of a semiconductor oxide conducting layer and a metal layer; the electrolyte is clamped between the working electrode and the absorber and contains at least one metal salt; the absorber is of a sub-wavelength multi-layer film metamaterial structure, and a resonance absorption cavity is formed by high-loss media and low-loss media in an alternating mode and conducts wide-spectrum absorption on energy of a solar wave band. Reversible deposition and dissolution of metal are achieved on the working electrode by controlling external voltage applied to the working electrode, reflection and absorption of energy of a solar wave band are controlled, and wide-spectrum dynamic regulation and control are achieved. According to the device, based on the micro-nano structure design, wide-spectrum dynamic regulation and control can be carried out on the spectrum of the solar wave band, and the device has the advantages of being simple in structure, high in regulation and control performance, large in modulation amplitude, capable of achieving wide-spectrum dynamic switching and the like.

Description

Technical Field

[0001] This invention relates to selective spectral dynamic broadband modulation, and more specifically to a radiation-cooling-solar-thermal dynamic modulation device based on reversible metal electrodeposition. Background Technology

[0002] In recent years, with industrialization and economic growth, energy issues have become a critical topic that countries around the world must face squarely. As greenhouse gas emissions continue to accumulate, the balance of ecosystems is severely affected, leading to a series of problems such as global warming, frequent extreme weather events, glacial melting, and sea-level rise.

[0003] The building sector accounts for over 30% of global energy consumption, with approximately 50% of that energy used for heating and cooling indoor spaces. These figures highlight the critical role of the building industry and the urgency of taking effective measures to reduce building energy consumption and carbon emissions. Therefore, reducing the energy consumption of building air conditioning systems for cooling and heating is a crucial step in reducing greenhouse gas emissions and achieving environmental protection goals. Against this backdrop, dynamic thermal management technology has attracted significant attention due to its ability to flexibly adjust system performance according to environmental changes, particularly radiative thermal management. This involves solar thermal collection in the solar radiation band and radiative cooling in the mid-infrared band, and these radiative mechanisms have significant application potential in building energy conservation. By dynamically adjusting the spectrum of materials, passive regulation of building energy consumption and thermal management can be achieved, lowering or raising the temperature of indoor spaces, thereby reducing the energy consumption of air conditioning systems.

[0004] Traditional solar heating devices, based on micro-nano structure designs, generate heat using solar radiation, while radiative cooling technology achieves cooling through radiative heat exchange between the Earth and outer space. However, most buildings operate in dynamically changing environments, including climate change, day-night cycles, and seasonal changes, leading to constant variations in outdoor temperatures and consequently, constantly evolving indoor environmental control requirements. Single-mode devices (solar heating only or daytime radiative cooling only) are limited in their effectiveness under such conditions. Therefore, designing dual-mode devices capable of switching between solar heating and radiative cooling would significantly improve energy efficiency in dynamic and complex environments. Combining solar heating with radiative cooling represents a competitive innovation direction.

[0005] To compensate for the shortcomings of single-mode devices and improve their energy utilization efficiency, scholars both domestically and internationally have conducted numerous studies on dual-mode devices combining solar heating and daytime radiative cooling. These studies on dynamic control of thermal radiation can be broadly categorized into four aspects: thermochromic control, mechanically driven thermochromic control, air humidity-driven thermochromic control, and electrochromic control. However, the first three control methods suffer from drawbacks such as slow control speed, poor spectral control effect, or inability to be specifically controlled according to human needs. In contrast, devices based on electrochromic control can reversibly change their transmittance or reflectance in the visible and infrared spectra under electrical stimulation, offering advantages such as faster switching speed, better switching effect, better robustness, and no moving parts.

[0006] Nevertheless, achieving synergistic multispectral modulation based on electrochromism remains challenging. On the one hand, it is difficult to obtain a wide spectral tuning range for overall performance; on the other hand, when achieving color-changing switching through reversible electroplating, conductive electrodes are required to apply an external electric field, but conductive electrodes that are transparent in the solar energy band are difficult to achieve. Although there are many methods for color-changing modulation to achieve solar heating and daytime radiative cooling, the effect on dual-mode devices for radiative cooling and solar thermal collection is still not good enough (most spectral modulation amplitudes are less than 80%). Summary of the Invention

[0007] To address the problem of poor performance of traditional electrochromic dual-mode devices in the prior art, this invention aims to provide a dynamic control device for radiation cooling and solar photothermal effects based on reversible metal electrodeposition.

[0008] The present invention discloses a reversible metal electrodeposition-based radiative cooling-solar thermal dynamic control device, comprising a working electrode, an electrolyte, and an absorber. The working electrode includes a micro / nano-structured conductive layer fabricated on a substrate, the micro / nano-structured conductive layer being composed of a semiconductor oxide conductive layer and a metal layer. The electrolyte, sandwiched between the working electrode and the absorber, contains at least one metal salt. The absorber employs a subwavelength multilayer metamaterial structure, including a resonant absorption cavity fabricated on the substrate and a semiconductor oxide conductive layer. The resonant absorption cavity is composed of alternating high-loss and low-loss dielectrics, enabling broadband absorption of solar energy. By controlling the external voltage applied to the working electrode, reversible deposition and dissolution of metal are achieved on the working electrode, thereby controlling the reflection and absorption of solar energy and realizing broadband dynamic control.

[0009] In a preferred embodiment, the metal layer is a Pt layer with a thickness between 0.5 nm and 10 nm.

[0010] In a preferred embodiment, the electrolyte is a gel electrolyte with a thickness between 1 mm and 2.0 mm.

[0011] In a preferred embodiment, the metal salt is silver nitrate or copper chloride.

[0012] In a preferred embodiment, the electrolyte contains an auxiliary agent, which is one or more of chloride, iodide, bromide, pyridine, and imidazole.

[0013] In a preferred embodiment, the electrolyte includes silver nitrate, tetrabutylammonium bromide, dimethyl sulfoxide, and polyvinyl butyral.

[0014] In a preferred embodiment, the high-loss medium is one or more of Pt, Ge, Si, W, and Ag.

[0015] In a preferred embodiment, the low-loss medium is one of SiO2, Al2O3, MgF2, CaF2, and BaF2.

[0016] In a preferred embodiment, the substrate layer is one of soda-lime glass, quartz glass, BaF2, CaF2, PP, PE, and PET.

[0017] In a preferred embodiment, the semiconductor oxide conductive layer is at least one of ITO, AZO, and FTO.

[0018] The radiative cooling-solar thermal dynamic control device based on reversible metal electrodeposition according to the present invention, based on micro-nano structure design, can dynamically control the spectrum of solar energy, possessing advantages such as simple structure, strong tunability, large modulation amplitude, and the ability to achieve wide-spectrum dynamic switching. Specifically, the present invention utilizes the optical properties of metamaterials, precisely controls the micro-nano structure of the absorber, and optimizes the metamaterial absorber to achieve wide-spectrum control in the solar energy band. Moreover, the present invention utilizes reversible metal electrodeposition technology to construct a reconfigurable metal layer on the working electrode, so as to dynamically change its state according to changes in external voltage, thereby achieving wide-spectrum dynamic control of solar energy reflectivity and transmittance. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a radiation-cooling-solar-thermal dynamic control device based on reversible metal electrodeposition according to a preferred embodiment of the present invention.

[0020] Figure 2 yes Figure 1 A schematic diagram of the assembly of a radiation cooling-solar photothermal dynamic control device.

[0021] Figure 3 yes Figure 1The spectrum of the radiation-cooling-solar-thermal dynamic control device is shown in the figure. In the figure, a shows the average solar absorptivity of the device in the solar band (0.3-2.5 μm) and b shows the infrared emissivity of the device in the mid-infrared band (4-16 μm).

[0022] Figure 4 yes Figure 1 The performance stability test diagrams of the radiative cooling-solar thermal dynamic control device are shown, where a is the device's cyclic test diagram and b is the device's potential cyclic curve.

[0023] Figure 5 yes Figure 1 The outdoor test results of the radiation cooling-solar thermal dynamic control device are shown in the figure. In the figure, a shows the outdoor test bench of the device, and b is the temperature change curve of the device in the outdoor test. Detailed Implementation

[0024] The preferred embodiments of the present invention are given below with reference to the accompanying drawings and described in detail.

[0025] like Figure 1 As shown, a preferred embodiment of the radiative cooling-solar thermal dynamic control device based on reversible metal electrodeposition according to the present invention comprises a working electrode, an electrolyte, and an absorber. By controlling the external voltage applied to the working electrode, reversible deposition (i.e., electroplating) and dissolution of metal can be achieved on the working electrode. Reversible metal electrodeposition is used to control the reflection and absorption of energy in the solar energy band, thereby achieving broadband dynamic switching / control. This solves the shortcomings of traditional electrochromic technology, which has high absorption in the solar light band and imperfect spectral control effect. Thus, the present invention inherits the advantages of reversible metal electrodeposition, such as large spectral modulation amplitude, simple manufacturing, and the ability to manufacture large-area devices, while solving the problem of broadband thermal radiation control.

[0026] The working electrode is located at the top and includes a micro / nanostructure fabricated on the substrate layer. This micro / nanostructure is a conductive layer composed of a semiconductor oxide conductive layer and a metal layer. The sheet resistance of the conductive layer does not exceed 1000 Ωsq. -1 In a preferred embodiment, the substrate layer is one of soda-lime glass, quartz glass, BaF2, CaF2, PP, PE, and PET. In a preferred embodiment, the semiconductor oxide conductive layer is at least one of ITO, AZO, and FTO, with a thickness between 1 nm and 1000 nm. In a preferred embodiment, the metal layer is Pt, with a thickness between 0.5 nm and 10 nm. In this embodiment, the substrate layer is quartz glass, the semiconductor oxide conductive layer is ITO, and the metal layer is Pt; both ITO and Pt are processed using multi-target magnetron sputtering technology.

[0027] The electrolyte / electrolyte is sandwiched between the working electrode and the absorber. In a preferred embodiment, the electrolyte is an encapsulated gel electrolyte. In a preferred embodiment, the thickness of the electrolyte is d1, corresponding to a value range of 1 mm ≤ d1 ≤ 2.0 mm. The electrolyte contains at least one metal salt. In a preferred embodiment, the metal salt is silver nitrate or copper chloride (CuCl2). The electrolyte contains an additive that forms a complex with the metal ions to optimize the metal deposition rate. In a preferred embodiment, the additive is one or more combinations of chloride, iodide, bromide, pyridine, and imidazole. In this embodiment, the electrolyte includes silver nitrate (AgNO3), the additive tetrabutylammonium bromide (TBABr), the solvent dimethyl sulfoxide (DMSO), and the solvent polyvinyl butyral (PVB).

[0028] The absorber is a transparent electrode located at the bottom, employing a subwavelength multilayer metamaterial structure. This structure includes a micro / nano structure fabricated on a substrate layer, consisting of a resonant absorption cavity and a semiconductor oxide conductive layer. The resonant absorption cavity is a periodic multilayer structure composed of alternating high-loss and low-loss dielectrics, enabling broadband absorption of solar energy. In a preferred embodiment, the substrate layer is one of soda-lime glass, quartz glass, BaF2, CaF2, PP, PE, and PET. In a preferred embodiment, the high-loss dielectric is one or more of Pt, Ge, Si, W, and Ag, with a thickness between 0.5 and 1000 nm. In a preferred embodiment, the low-loss dielectric is one of SiO2, Al2O3, MgF2, CaF2, and BaF2, with a thickness between 1 and 1400 nm. In a preferred embodiment, the sheet resistance of the semiconductor oxide conductive layer is ≤1000 Ωsq. -1 In a preferred embodiment, the semiconductor oxide conductive layer is at least one of ITO, AZO, and FTO, with a thickness between 1 nm and 1000 nm. In this embodiment, the substrate is quartz glass, the resonant absorption cavity is Pt / SiO2, the high-loss dielectric is Pt, the low-loss dielectric is SiO2, and the semiconductor oxide conductive layer is ITO. Both ITO and Pt are processed using multi-target magnetron sputtering technology, and SiO2 is processed using plasma-enhanced chemical vapor deposition technology.

[0029] The working principle of the radiation-cooled-solar-thermal dynamic control device in this embodiment is based on a reversible silver electroplating system. When a negative voltage is applied to the working electrode, silver ions (Ag) in the electrolyte... ＋Electrons are gained on the surface of the metal layer at the working electrode, forming an Ag film, which switches the device to radiative cooling mode. In this mode, the Ag film has a relatively high reflectivity, reflecting the energy of the solar spectrum, while the top quartz glass has a high emissivity in the infrared, allowing heat to be emitted as thermal radiation through the atmospheric window. When a positive voltage is applied, the deposited Ag film undergoes an oxidation reaction on the working electrode, becoming Ag. ＋ It dissolves in the electrolyte, thus switching the device to solar heating mode. In this mode, both the working electrode and the electrolyte have low reflectivity and high transmittance in the 0.3-2.5 μm band, allowing most of the energy in the solar spectrum to enter the absorber and be utilized.

[0030] Thus, this invention combines reversible metal electrodeposition with micro-nano structure design, enabling dynamic switching of thermal radiation between high reflectivity and high absorptivity, achieving broad-spectrum dynamic control of the solar energy spectrum, and enabling electrochromic thin film devices to achieve superior solar energy collection and radiative cooling effects.

[0031] The following is combined Figure 2 Brief introduction Figure 1 The assembly process of radiation cooling-solar photothermal dynamic control device.

[0032] First, a quartz glass with a thickness of 1 mm and a size of 5 cm × 5 cm was selected as the first and base layers. It was then ultrasonically cleaned with acetone, isopropanol, and deionized water in sequence, and dried under a nitrogen flow to obtain a clean base.

[0033] Then, an ITO / Pt bilayer structure is formed on the quartz glass substrate using a multi-target magnetron sputtering device to provide a working electrode; a resonant absorption cavity of Pt / SiO2 and ITO is formed on the quartz glass substrate using a multi-target magnetron sputtering device / plasma-enhanced chemical vapor deposition (PECVD) device to provide an absorber.

[0034] Next, the working electrode, absorber, and intermediate sealing insulating gasket are assembled together. The insulating gasket's function is to ensure the electrical insulation and structural stability of the device.

[0035] Finally, the gel-like electrolyte is injected through the side openings into the space between the working electrode and the absorber using a syringe, completing the device encapsulation. It should be understood that the electrolyte contains the thickener PVB, and the electrolyte injected between the working electrode and the absorber has high viscosity and poor flowability; therefore, simple encapsulation can prevent leakage.

[0036] A broadband dynamic switching electrochromic device based on reversible metal electrodeposition can be obtained by leading out wire terminals.

[0037] like Figure 3 As shown, in the solar heating mode, the device achieves an average solar absorptivity of 90.53% in the 300 nm-2500 nm wavelength range and an average infrared emissivity of 81.58% in the 4 μm-16 μm wavelength range. In the radiative cooling mode, the device achieves an average solar reflectivity of 90.55% in the 300 nm-2500 nm wavelength range and an average infrared emissivity of 84.11% in the 4 μm-16 μm wavelength range. The average solar absorptivity, Asol, is calculated by weighted integration of the spectrum in the wavelength range of 0.3-2.5 μm at AM1.5.

[0038]

[0039] Where Asol is the average absorptivity of solar energy, representing the percentage of solar energy absorbed; α(λ) is the spectral absorptivity, calculated using TMM (A = 1 - TR); and IDirect(λ) is the energy of solar energy that passes through the atmosphere to reach the Earth's surface.

[0040] like Figure 4 As shown, after 50 cycles, within the 300 nm-1000 nm range, the device still achieves a reflectivity switching of up to 6.63%-91.79%, demonstrating excellent mode switching performance. The potential cycling curves measured by the electrochemical workstation, with the vertical axis representing the surface current per unit area (mA / cm²) and the horizontal axis representing the cycle time, show that the surface current per unit area gradually stabilizes with increasing potential cycling count. The maximum surface current per unit area during the electroplating process can reach -3 mA / cm². 2 The surface current per unit area during the dissolution process can reach a maximum of 2.5 mA / cm². 2 .

[0041] like Figure 5As shown, the outdoor experimental platform includes a testing chamber, a weather station, an electrochemical workstation, and a data acquisition system. The device undergoes outdoor experiments within the testing chamber. At 12:20 PM, with an ambient humidity of 26.1% and an instantaneous total solar radiation intensity of 499 W / m², the device absorbs solar energy and converts it into heat, causing its temperature to rise approximately 18.56°C relative to the ambient temperature, indicating it is in solar heating mode. When switching to radiative cooling mode, the device can lower its temperature to match the ambient temperature within 20 minutes. At 4:00 PM, with an ambient humidity of 28.8% and an instantaneous total solar radiation intensity of 90 W / m², under daytime solar radiation, the device in radiative cooling mode achieves a temperature difference 6.42°C lower than the ambient temperature. At 6:00 PM, with an ambient humidity of 33.3% and no solar radiation, the device in radiative cooling mode achieves a temperature difference 8.19°C lower than the ambient temperature. Throughout the experiment, the device demonstrated remarkable temperature control performance. Whether in solar heating mode or radiative cooling mode, the device achieved effective temperature regulation and responded quickly to environmental changes, exhibiting excellent mode switching performance and temperature control effect.

[0042] The following is a brief introduction to the construction of the radiation-cooling-solar-thermal dynamic control device based on reversible metal electrodeposition according to the present invention.

[0043] First, a device structure for broadband absorption of solar energy is designed based on the principle of optical resonance. Specifically, a suitable dielectric material is selected according to the requirement of broadband high absorption in the solar energy band. The thickness of each selected material layer is optimized using a genetic algorithm to achieve efficient weighted absorption of solar energy in the solar energy band. The spectra (reflectance spectrum R and absorptivity spectrum A) of the structure before and after metal plating are calculated using the transfer matrix method (TMM). Numerical simulation is performed to verify whether the structure meets the broadband modulation requirements of the solar energy band, and further optimization is carried out based on the simulation results.

[0044] Secondly, based on various micro-nano fabrication methods, planar multilayer micro-nano structures in the working electrode and absorber are fabricated on the substrate layer. Precise control of thin film deposition allows for the creation of micro-nano structure layers with the desired optical and electrical properties, providing a foundation for wide-spectrum dynamic control of the device. Specifically, electron beam evaporation, atomic layer deposition, or multi-target magnetron sputtering are used to fabricate the metal layer of the working electrode and the high-loss dielectric in the absorber; electron beam evaporation, multi-target magnetron sputtering, chemical vapor deposition, or inductively coupled plasma chemical vapor deposition are used to fabricate the low-loss dielectric in the absorber; and multi-target magnetron sputtering or electron beam evaporation is used to fabricate the semiconductor oxide conductive layer in the working electrode and absorber.

[0045] In specific processing steps, chemical vapor deposition (PECVD) or inductively coupled plasma chemical vapor deposition (ICP-CVD) techniques are used to achieve low-loss dielectric deposition. PECVD is performed in a low-pressure environment, generating a low-temperature plasma glow discharge at the cathode (sample tray) of the process chamber, while simultaneously heating the sample to a predetermined temperature using the glow discharge or an additional heating element. Subsequently, a suitable amount of process gas is introduced, and after undergoing a series of chemical and plasma reactions, a solid film is finally formed on the sample surface. For multi-target magnetron sputtering, a multi-target magnetron sputtering deposition system is used for sputtering deposition. This system can sputter and deposit various materials, including Pt, Ag, Cu, Au, and ITO, as well as related composite films. The fabrication principle involves introducing argon (Ar) gas as the sputtering gas into the vacuum chamber of the magnetron sputtering system and applying a sufficiently high voltage to the cathode target to induce a glow discharge, forming plasma. During this process, charged particles in the plasma move under the influence of the Lorentz force, and the argon gas is ionized to produce argon ions (Ar). ＋ Argon ions and electrons. Under the influence of an electric field, argon ions (Ar...) ＋ The electrons are accelerated toward the cathode target and bombard the target surface with high energy, sputtering the target atoms out. Finally, these atoms are deposited on the substrate to form a thin film.

[0046] Finally, the overall device was constructed and tested according to a typical sandwich structure. A reversible metal electrodeposition structure was used to reflect and absorb energy in the solar energy band, achieving dynamic control of the solar energy. Specifically, the reflectivity of the entire device was measured using an integrating sphere. The results showed that the measured reflectivity perfectly matched the theoretically calculated reflectivity, indicating that multi-target magnetron sputtering, atomic layer deposition, or chemical vapor deposition techniques can prepare high-quality nanofilms. Electroplating tests were performed on the device by connecting it to a three-electrode chemical workstation, setting a cyclic voltage, and measuring the spectral changes before and after electroplating.

[0047] This invention employs a subwavelength multilayer metamaterial absorber and utilizes a genetic algorithm to optimize the device structure, ensuring extremely high absorptivity across the entire solar wavelength range. Furthermore, this invention is the first to combine a high-performance metamaterial absorber with reversible metal electrodeposition technology. This innovation overcomes the limitations of traditional materials for heat collection, significantly improving the device's performance in solar heating and radiative cooling. This enables efficient dynamic switching between high solar reflectivity and high solar absorptivity, significantly enhancing the device's photothermal management capabilities and improving its practicality and stability.

[0048] The device designed in this invention can adapt to different seasons and all-weather photothermal demands, switching modes according to actual human needs, thus achieving true all-weather, all-season photothermal management. This is of great significance for building energy conservation and intelligent vehicles, as it can flexibly adjust photothermal performance according to environmental changes and user needs, thereby improving energy efficiency and comfort.

[0049] Furthermore, the fabrication of the devices of the present invention is based on conventional coating technology, and all micro- and nano-structures can be fabricated using multi-target magnetron sputtering, which reduces costs and is expected to enable large-scale fabrication, making the devices of the present invention highly economical and have market potential.

[0050] Moreover, the device structure of the present invention is simple, without complex feed lines, and has low manufacturing cost, making it highly feasible and competitive.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various variations can be made to the above embodiments of the present invention. That is, all simple and equivalent changes and modifications made based on the claims and description of this invention fall within the protection scope of the claims. All aspects not described in detail in this invention are conventional technical content.

Claims

1. A dynamic control device for radiation-cooled solar thermal energy based on reversible metal electrodeposition, characterized in that, The device comprises a working electrode, an electrolyte, and an absorber. The working electrode includes a micro / nano-structured conductive layer fabricated on a substrate, which consists of a semiconductor oxide conductive layer and a metal layer. The electrolyte, sandwiched between the working electrode and the absorber, contains at least one metal salt. The absorber is a subwavelength multilayer metamaterial structure, comprising a resonant absorption cavity fabricated on the substrate and a semiconductor oxide conductive layer. The resonant absorption cavity is composed of alternating high-loss and low-loss dielectrics, enabling broadband absorption of solar energy. By controlling the external voltage applied to the working electrode, reversible deposition and dissolution of metal are achieved on the working electrode, thereby controlling the reflection and absorption of solar energy and realizing broadband dynamic modulation.

2. The device according to claim 1, characterized in that, The metal layer is a Pt layer with a thickness between 0.5 nm and 10 nm.

3. The device according to claim 1, characterized in that, The electrolyte is a gel electrolyte with a thickness between 1 mm and 2.0 mm.

4. The device according to claim 1, characterized in that, The metal salt is silver nitrate or copper chloride.

5. The device according to claim 4, characterized in that, The electrolyte contains additives, which are one or more combinations of chloride, iodide, bromide, pyridine, and imidazole.

6. The device according to claim 5, characterized in that, The electrolytes include silver nitrate, tetrabutylammonium bromide, dimethyl sulfoxide, and polyvinyl butyral.

7. The device according to claim 1, characterized in that, The high-loss medium is one or more of Pt, Ge, Si, W, and Ag.

8. The device according to claim 1, characterized in that, The low-loss medium is one of SiO2, Al2O3, MgF2, CaF2, and BaF2.

9. The device according to claim 1, characterized in that, The base layer is one of soda-lime glass, quartz glass, BaF2, CaF2, PP, PE and PET.

10. The device according to claim 1, characterized in that, The semiconductor oxide conductive layer is at least one of ITO, AZO and FTO.

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