Radiation cooling assisted self-sustaining efficient moisture-induced power generation device and preparation method thereof

Abstract

The invention relates to a radiation cooling assisted self-maintaining efficient moisture induced power generation device and a preparation method thereof. The self-maintaining efficient moisture induced power generation device comprises a hydrophobic porous polymer radiation cooling top layer, a hydrophilic ionized water gel bottom layer and electrodes arranged on the two sides of the hydrophilic ionized water gel bottom layer. The hydrophilic ion hydrogel bottom layer can spontaneously absorb moisture in air and dissociate ions; the hydrophobic porous polymer radiation cooling top layer allows evaporated steam to pass through, and can adjust the moisture migration rate and influence the adsorption temperature of the bottom layer component; the hydrophilic ion hydrogel bottom layer is composed of polyvinyl alcohol, inositol phosphate and lithium chloride. Compared with the prior art, the method has the advantages that the influence of the radiation cooling process on moisture adsorption-desorption kinetics is utilized, continuous moisture and ion flow in the material is kept in a fluctuating natural environment, and a new way for realizing efficient and stable moisture power generation by utilizing the natural environment is provided from the perspective of thermodynamics.

Description

Technical Field

[0001] The invention relates to the technical field of functional materials, and in particular to a radiation cooling-assisted self-sustaining high-efficiency moisture-induced power generation device and a preparation method thereof. Background Art

[0002] Harvesting energy from ubiquitous water vapor is a promising approach to alleviate the energy crisis. Recent advances in nanoscience have made it possible to harvest electricity directly from ambient moisture through moisture-induced power generation technology. Moisture generators use spontaneous moisture adsorption on functionalized nanomaterials to convert the chemical potential energy released by the state transition of water molecules into electrical energy. Although early studies achieved continuous voltage output by establishing a moisture gradient in the material, the problem of gradient driving force weakening and current decay as the water content becomes saturated during a single adsorption process still exists.

[0003] To address this challenge, existing studies have integrated the water adsorption and desorption processes to achieve continuous water and ion flow, but they have mainly studied the water adsorption and desorption caused by humidity changes. In practical applications, fluctuations in solar radiation and ambient temperature also provide opportunities to promote water circulation. In order to construct asymmetric hydrophilic and hydrophobic structures, the hydrophobic side of these devices is usually loaded with materials with high solar radiation absorption rates such as carbon black, carbon nanotubes or MXene. Although the heating of the hydrophobic side by solar radiation can accelerate water evaporation and ion transport to a certain extent, the continuous absorption of solar radiation will inevitably lead to heat conduction from the hydrophobic side to the hydrophilic side, ultimately limiting the moisture absorption of the hydrophilic side and causing the electric field to collapse.

[0004] Therefore, how to systematically consider the impact of natural environmental factors on the performance of wet gas power generation and develop a wet gas power generation device that can maintain stable and continuous output under fluctuating natural environments is of great significance for the practical application of actual power generation technology. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a self-sustaining high-efficiency moisture-induced power generation device assisted by radiation cooling and a preparation method thereof, aiming to utilize the influence of the radiation cooling process on the moisture adsorption-desorption dynamics, maintain continuous moisture and ion flow inside the material in a fluctuating natural environment, and propose a new way to utilize the natural environment to achieve efficient and stable moisture power generation from a thermodynamic point of view.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] The first aspect of the present invention provides a self-sustaining high-efficiency moisture-induced power generation device assisted by radiation cooling, the self-sustaining high-efficiency moisture-induced power generation device comprising a hydrophobic porous polymer radiation cooling top layer, a hydrophilic ion hydrogel bottom layer, and electrodes disposed on both sides of the hydrophilic ion hydrogel bottom layer;

[0008] The hydrophilic ionic hydrogel bottom layer can spontaneously absorb moisture in the air and dissociate ions;

[0009] The hydrophobic porous polymer radiative cooling top layer allows the evaporating vapor to pass through and can regulate the rate of moisture migration and affect the adsorption temperature of the bottom layer components;

[0010] The hydrophilic ion hydrogel bottom layer is composed of polyvinyl alcohol, cyclohexanehexol phosphate and lithium chloride, and can spontaneously absorb moisture from the air and provide dissociated charge carriers and ion transmission paths for power generation.

[0011] Furthermore, the preparation method of the hydrophobic porous polymer radiation cooling top layer comprises:

[0012] The polymer powder, acetone and deionized water were mixed and then stirred well at room temperature to prepare a precursor solution;

[0013] Immersing the template in the precursor solution to evenly coat the polymer solution on the surface of the template, and then taking it out and drying it naturally;

[0014] The dried coated template was immersed in a hydrochloric acid solution. After the template was completely dissolved, it was placed in ethanol for ultrasonic treatment to remove the residual hydrochloric acid solution, and then dried to obtain a radiation cooling polymer top layer with a hierarchical porous structure.

[0015] Furthermore, the polymer material is selected from any one of vinylidene fluoride-hexafluoropropylene copolymer, polyvinylidene fluoride, polymethyl methacrylate, and cellulose acetate.

[0016] Furthermore, the preparation method of the hydrophilic ionic hydrogel bottom layer comprises:

[0017] Add lithium chloride to deionized water and stir until completely dissolved;

[0018] Add polyvinyl alcohol and cyclohexanehexol phosphate to the lithium chloride aqueous solution, and stir them fully in an oil bath to completely dissolve them to obtain a mixed solution;

[0019] Ultrasonic treatment is performed on the mixed solution to fully remove bubbles in the solution, and the mixed solution after ultrasonic treatment is poured into a mold;

[0020] The mold containing the mixed solution is frozen, then thawed and demolded at room temperature to obtain the ionic hydrogel.

[0021] The second aspect of the present invention provides a method for preparing the above-mentioned radiative cooling-assisted self-sustaining high-efficiency moisture-induced power generation device, comprising the following steps:

[0022] A hydrophobic porous polymer radiative cooling top layer having high solar reflectivity and high infrared emissivity and allowing vapor to pass through is prepared by:

[0023] Mixing polymer powder, acetone, and deionized water in a preset ratio and stirring to obtain a precursor solution;

[0024] The hydrophobic porous polymer radiation cooling top layer is obtained by impregnating the precursor solution with the template, drying, acid dissolving the template, ultrasonic cleaning and drying again;

[0025] The steps of preparing a hydrophilic ionic hydrogel bottom layer comprising polyvinyl alcohol, cyclohexane hexyl phosphate and lithium chloride and having the ability of hygroscopicity, ion dissociation and ion transport are as follows:

[0026] Dissolve lithium chloride in water;

[0027] Add polyvinyl alcohol and cyclohexane hexyl phosphate and stir to dissolve in an oil bath;

[0028] After ultrasonic degassing, the mixture is poured into a mold, and the ionic hydrogel is obtained through freezing, thawing and demoulding;

[0029] The positive electrode and the negative electrode are respectively attached to the two sides of the hydrophilic ion hydrogel bottom layer, and the hydrophobic porous polymer radiation cooling top layer is placed above the positive electrode, and pressed and assembled to form a self-sustaining high-efficiency moisture-induced power generation device assisted by radiation cooling.

[0030] Furthermore, during the preparation of the precursor solution, the mass ratio of polymer powder, acetone and deionized water is 1:8:1, and the stirring time is 30-60 minutes.

[0031] Furthermore, the template is a 2 mm thick nickel foam, which is immersed in a 1 mol / L hydrochloric acid solution for 72-96 hours, ultrasonically treated in ethanol for 15-20 minutes, and dried in a 50° C. drying oven for 2-3 hours.

[0032] Furthermore, when preparing the hydrophilic ionic hydrogel bottom layer, lithium chloride was stirred at room temperature for 30 minutes until it was completely dissolved, and polyvinyl alcohol and cyclohexanehexol phosphate were added and stirred in a 95° C. oil bath for 3-4 hours.

[0033] Furthermore, the mass concentration of the polyvinyl alcohol in the entire liquid is 10wt%, the mass concentration of the lithium chloride in the entire liquid is 5-20wt%, and the mass concentration of the cyclohexanehexol phosphate in the entire liquid is 7-22wt%.

[0034] Furthermore, the thickness of the hydrophilic ion hydrogel bottom layer is 0.5-2 mm, which is adjusted by using molds with different thicknesses.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. The present invention combines a hydrophobic porous polymer top layer and a hygroscopic ion hydrogel bottom layer to form a wet gas power generation device with an asymmetric hydrophilic and hydrophobic structure. The graded pore size of the top layer allows water vapor to pass through while maintaining good radiation cooling performance, so that the device can continuously drive the directional flow of water and ions in the dynamic cycle of adsorption-desorption. In addition, the radiation cooling effect of the porous polymer top layer gives the device excellent outdoor output stability. The high solar reflectivity can prevent the inherent absorption of solar radiation by water, avoid the reduction of the moisture gradient and ion migration rate in the hydrogel due to excessive evaporation during the day, and the radiation cooling effect of the top layer at night can balance the adsorption heat of the hydrogel to accelerate moisture adsorption. The present invention uses radiation heat transfer with the environment to regulate the adsorption-desorption dynamics of the device during the wet gas power generation process, and achieves long-term continuous and stable electrical output under a fluctuating natural environment, providing a new idea for improving the output performance of wet gas generators in hot and dry areas that are usually not suitable for work.

[0037] 2. In the present invention, polyvinyl alcohol and cyclohexane hexol phosphate as cross-linking points establish a polymer skeleton, and the abundant nanochannels in the hydrogel provide a pathway for the directional transport of water and ions; when interacting with water molecules, cyclohexane hexol phosphate can dissociate a large number of mobile ions, resulting in effective charge separation and an increase in voltage output; and the introduction of lithium chloride significantly improves the hygroscopic capacity of the hydrogel, enabling it to spontaneously collect moisture from the atmosphere and quickly establish a gradient of water content and ion concentration.

[0038] 3. The ionic hydrogel prepared by the process conditions of the present invention has excellent ion transport performance. Different from the strategy of immersing the synthesized hydrogel in a high-concentration salt solution to adjust the aggregation of polymer chains and thus improve the mechanical and electrical properties, due to the strong hydration of lithium ions, directly adding lithium chloride when the polymer is dissolved can effectively hinder the formation of hydrogen bonds during the freeze-thaw process, which helps to increase the ion transport rate, thereby significantly increasing the current density.

[0039] 4. The moisture-induced power generation device provided by the present invention has a simple preparation process, a reasonable and controllable structural design, and can be customized in size and connection method according to changes in application scenarios to meet the needs of large-scale manufacturing and integrated use. It has broad application prospects in off-grid distributed power supplies, health monitoring, information storage and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Schematic diagram of the structure and working principle of the wet gas power generation device provided by the present invention; wherein a is a structural explosion diagram of the wet gas power generation device in an embodiment of the present invention, and b is a working principle diagram of the wet gas power generation device in an embodiment of the present invention under a day and night cycle;

[0041] Figure 2 This is a spectrum characteristic diagram of the top layer of the moisture power generation device in an embodiment of the present invention;

[0042] Figure 3 This is a microscopic morphology of the top layer of the moisture power generation device in an embodiment of the present invention;

[0043] Figure 4 This is a test diagram showing the output performance of a wet gas power generation device changing with temperature in an embodiment of the present invention;

[0044] Figure 5 This is a test diagram showing the output performance of a wet gas power generation device changing with relative humidity in an embodiment of the present invention;

[0045] Figure 6 This is a test diagram of the voltage and current of the wet gas power generation device changing with the load resistance value in an embodiment of the present invention;

[0046] Figure 7 This is a comparison chart of the outdoor output sustainability of the wet gas power generation devices manufactured in the embodiment of the present invention and the comparative example. DETAILED DESCRIPTION

[0047] In general, the present invention discloses a self-sustaining high-efficiency moisture-induced power generation device assisted by radiation cooling, which belongs to the field of functional material technology. The moisture-induced power generation device includes a hydrophobic porous polymer radiation cooling top layer and a hydrophilic ion hydrogel bottom layer with electrodes attached on both sides; the hydrogel bottom layer can spontaneously absorb moisture in the air and dissociate ions, and the porous top layer allows evaporated steam to pass through, and the dynamic balance of adsorption-desorption drives moisture and ions to flow continuously through negatively charged nanochannels, thereby generating continuous electrical energy output; the radiation cooling top layer has high solar reflectivity and high infrared emissivity, thereby avoiding the attenuation of moisture migration rate due to excessive evaporation during the day, and reducing the adsorption temperature of the hydrogel at night to accelerate moisture adsorption; the ion hydrogel is composed of polyvinyl alcohol, cyclohexane hexanol phosphate and lithium chloride, which provides excellent moisture absorption capacity, abundant dissociated charge carriers and efficient ion transmission performance for the moisture power generation process. The present invention provides a new idea for improving the output performance of moisture generators in hot and dry areas, and has broad application prospects.

[0048] The self-sustaining high-efficiency moisture-induced power generation device assisted by radiation cooling in the present invention comprises a hydrophobic porous polymer radiation cooling top layer and a hydrophilic ionic hydrogel bottom layer with electrodes attached on both sides; the hydrogel bottom layer can spontaneously absorb moisture in the air and dissociate ions, while the porous top layer allows evaporated steam to pass through, and the dynamic balance of adsorption-desorption drives moisture and ions to continuously flow through negatively charged nanochannels, thereby generating continuous electrical energy output; the graded porous radiation cooling top layer has high solar reflectivity and high infrared emissivity, which can avoid the attenuation of moisture migration rate due to excessive evaporation during the day, and reduce the adsorption temperature of the hydrogel at night to accelerate moisture adsorption; the ionic hydrogel is composed of polyvinyl alcohol, cyclohexanehexol phosphate and lithium chloride, providing excellent moisture absorption capacity, abundant dissociated charge carriers and efficient ion transmission performance for the wet gas power generation process.

[0049] In a specific implementation, the method for preparing the hierarchical porous radiation cooling top layer of the radiation cooling-assisted self-sustaining high-efficiency moisture-induced power generation device comprises the following steps:

[0050] (1) polymer powder, acetone and deionized water were mixed in a mass ratio of 1:8:1, and then stirred at room temperature for 30 to 60 minutes to prepare a precursor solution;

[0051] (2) immersing a 2 mm thick nickel foam as a template into the precursor solution described in step (1), so that the polymer solution is evenly coated on the surface of the nickel foam, and then taking it out and drying it naturally;

[0052] (3) The dried nickel foam coating was immersed in a 1 mol L -1 The foamed nickel is placed in a hydrochloric acid solution for 72 to 96 hours. After the foamed nickel is completely dissolved, it is placed in ethanol for ultrasonic treatment for 15 to 20 minutes to remove the residual hydrochloric acid solution. It is then dried in a drying oven at 50°C for 2 to 3 hours to obtain a radiation cooling polymer top layer with a hierarchical porous structure.

[0053] It should be noted that the polymer material in the above step (1) can be any one of vinylidene fluoride-hexafluoropropylene copolymer (P(VdF-HFP)), polyvinylidene fluoride (PVDF), polymethyl methacrylate (PMMA) and cellulose acetate.

[0054] In a specific implementation, the method for preparing the ionic hydrogel bottom layer of the radiation cooling-assisted self-sustaining high-efficiency moisture-induced power generation device comprises the following steps:

[0055] (1) Add lithium chloride into deionized water and stir at room temperature for 30 min until the lithium chloride is completely dissolved;

[0056] (2) adding polyvinyl alcohol (PVA) and cyclohexanehexol phosphate (PA) to the lithium chloride aqueous solution obtained in step (1), and stirring them fully in a 95° C. oil bath for 3 to 4 hours to completely dissolve them;

[0057] (3) subjecting the mixed solution obtained in step E to ultrasonic treatment for 30 min to fully remove bubbles in the solution, and pouring the mixed solution after ultrasonic treatment into a mold;

[0058] (4) The mold containing the mixed solution was frozen at -15°C for 8 h, then thawed and demolded at room temperature. Since the introduction of lithium chloride weakened the hydrogen bonding effect, the obtained ionic hydrogel had a loose cross-linked structure and good interface adhesion, and could be tightly connected to the electrode and the radiation cooling top layer.

[0059] Wherein, in the mixed solution obtained in the above step (3), the mass concentration of polyvinyl alcohol is 10wt%, the mass concentration of lithium chloride is 5-20wt%, and the mass concentration of cyclohexanehexol phosphate is 7-22wt%;

[0060] In addition, the thickness of the ionic hydrogel obtained in step (4) is 0.5 to 2 mm, which can be adjusted by using molds of different thicknesses.

[0061] In the specific implementation, the positive electrode and the negative electrode are respectively attached to the two sides of the ionic hydrogel obtained in the above steps, and the obtained hierarchical porous radiation cooling polymer top layer is placed on the positive electrode, and then pressed and assembled under a pressure of about 200 Pa to obtain a self-sustaining high-efficiency moisture-induced power generation device assisted by radiation cooling.

[0062] In a specific implementation, the material of the positive and negative electrodes can be any one of gold, silver, copper, aluminum, iron, carbon cloth, carbon nanotube electrode, graphene electrode and silver nanowire.

[0063] In specific implementation, the radiation cooling-assisted self-sustaining high-efficiency moisture-induced power generation device manufactured by the present invention can be constructed into an array structure device by series, parallel or series-parallel combination integration to increase the power output, thereby meeting the energy consumption requirements in different application scenarios.

[0064] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms and other features not clearly described in this technical solution are all considered to be common technical features disclosed in the prior art.

[0065] Example 1

[0066] The structure and working principle of the wet gas power generation device according to the embodiment of the present invention are described below with reference to the accompanying drawings:

[0067] like Figure 1As shown, the radiation cooling-assisted self-sustaining high-efficiency moisture-induced power generation device includes: a hydrophobic porous polymer radiation cooling top layer and a hydrophilic ion hydrogel bottom layer with positive and negative electrodes attached on both sides.

[0068] Specifically, the ionic hydrogel layer can spontaneously absorb moisture from the air and dissociate into ions, while the porous polymer top layer allows evaporated vapor to pass through. The dynamic balance of adsorption-desorption drives moisture and ions to continuously flow through the negatively charged nanochannels, thereby generating continuous power output.

[0069] In addition, the radiation cooling effect of the graded porous polymer top layer prevents the hydrogel from absorbing solar radiation, thereby avoiding excessive evaporation during the day that leads to a decrease in the moisture gradient and ion migration rate within the hydrogel. At night, the adsorption temperature of the hydrogel is reduced to accelerate moisture adsorption, which helps to establish a stable adsorption-desorption cycle during the day and night alternation.

[0070] The preparation process and performance of the self-sustaining high-efficiency moisture-induced power generation device assisted by radiation cooling are described in detail below:

[0071] 1. Fabrication of self-sustaining and highly efficient moisture-induced power generation devices assisted by radiative cooling

[0072] (1) First, 2 g of vinylidene fluoride-hexafluoropropylene copolymer (P(VdF-HFP)), 16 g of acetone and 2 g of deionized water were mixed and stirred at room temperature for 30 min until the polymer powder was completely dissolved to obtain a precursor solution;

[0073] (2) A nickel foam with an area of ​​1×1 cm and a thickness of 2 mm was used as a template and immersed in the above-mentioned precursor solution to evenly coat the nickel foam surface. After being taken out, it was naturally dried in a fume hood for 2 h;

[0074] (3) The dried nickel foam coating was immersed in a 1 mol L -1 The nickel foam was completely dissolved in a hydrochloric acid solution for 72 h, and then ultrasonically treated in ethanol for 15 min to remove the residual hydrochloric acid solution in the pores, and dried in a drying oven at 50 ° C for 2 h to obtain a radiation cooling polymer top layer with a hierarchical porous structure.

[0075] (4) Secondly, 4.5 g of lithium chloride was added to 12.5 mL of deionized water and stirred at room temperature for 30 min until the lithium chloride was completely dissolved. Subsequently, 3 g of polyvinyl alcohol (PVA) and 7.5 mL of hexadecyl phosphate (PA) solution were added to the lithium chloride aqueous solution, and the mixed solution was fully stirred in a 95 °C oil bath for 3 h to completely dissolve the polyvinyl alcohol;

[0076] (5) ultrasonically treating the obtained mixed solution for 30 min to fully remove bubbles in the solution, and introducing the mixed solution after ultrasonic treatment into a groove polytetrafluoroethylene (PTFE) mold with a groove area of ​​1×1 cm and a depth of 2 mm;

[0077] (6) The mold containing the mixed solution was frozen at -15°C for 8 h, then thawed and demolded at room temperature. Since the introduction of lithium chloride weakened the hydrogen bonding effect, the obtained ionic hydrogel had a loose cross-linked structure and good interface adhesion, and could be tightly connected to the electrode and the radiation cooling top layer.

[0078] (7) Finally, the moisture-induced power generation device was assembled. Two carbon cloth electrodes were respectively attached to the two sides of the prepared ionic hydrogel, and the obtained hierarchical porous radiation cooling polymer top layer was placed on the electrodes. Then, the devices were pressed and assembled under a pressure of about 200 Pa to obtain a self-sustaining and efficient moisture-induced power generation device assisted by radiation cooling. The electrode between the porous polymer and the ionic hydrogel was the positive electrode, and the bottom electrode was the negative electrode. The thickness of the hierarchical porous radiation cooling polymer top layer and the ionic hydrogel was 2 mm.

[0079] The reagents used in the above preparation process are: polyvinyl alcohol (PVA, hydrolysis degree: 98-99%, polymerization degree: 2400-2500), cyclohexane hexol phosphate solution (PA, 50wt% aqueous solution) and lithium chloride (99.9%) purchased from Aladdin Reagent Company. Vinylidene fluoride-hexafluoropropylene copolymer (P(VdF-HFP), M w ~400000, M n ~130000) and acetone (99%) were purchased from Sigma-Aldrich Reagent Company. Carbon cloth and nickel foam were purchased from Guangdong Kelude New Energy Technology Co., Ltd. No further purification was required for the reagents used.

[0080] Figure 2The spectral characteristic diagram of the top layer of the wet gas power generation device in the embodiment of the present invention; the optical characteristics of the porous polymer radiation cooling top layer obtained in this embodiment in the wavelength range of 0.3 to 2.5 μm were characterized using an ultraviolet-visible-near infrared spectrometer (brand: Shimadzu, model: UV-3600i Plus), and its average solar reflectivity was 0.96; the emissivity of the porous polymer radiation cooling top layer obtained in this embodiment in the wavelength range of 3 to 25 μm was tested using a Fourier transform infrared spectrometer (brand: Thermo Fisher Scientific, model Nicolet iS50), and its average infrared emissivity in the atmospheric window (wavelength range 8 to 15 μm) was 0.97. The above test results show that due to the inherent electromagnetic properties of the vinylidene fluoride-hexafluoropropylene copolymer and its rich multi-level pores, the porous polymer top layer prepared in this embodiment has good spectral characteristics and can meet the requirements for achieving daytime radiation cooling.

[0081] Figure 3 : is a microscopic morphology of the top layer of the moisture induced power generation device in an embodiment of the present invention; Figure 3 As shown, the porous radiation cooling top layer prepared in this embodiment has graded pores with a wide distribution of pore sizes, mainly concentrated around 0.4, 4.5 and 150 μm. Among them, the abundant nanopores and micropores can strongly scatter sunlight, while the pores distributed at 150 μm allow evaporated water vapor to pass through.

[0082] Comparative Example 1

[0083] (1) 4.5 g of lithium chloride was added to 12.5 mL of deionized water and stirred at room temperature for 30 min until the lithium chloride was completely dissolved. Subsequently, 3 g of polyvinyl alcohol (PVA) and 7.5 mL of hexadecyl phosphate (PA) solution were added to the lithium chloride aqueous solution, and the mixed solution was fully stirred in a 95°C oil bath for 3 h to completely dissolve the polyvinyl alcohol;

[0084] (2) ultrasonically treating the obtained mixed solution for 30 min to fully remove bubbles in the solution, and introducing the mixed solution after ultrasonic treatment into a groove polytetrafluoroethylene (PTFE) mold with a groove area of ​​1×1 cm and a depth of 2 mm;

[0085] (3) The mold containing the mixed solution was frozen at -15°C for 8 h, then thawed and demolded at room temperature to obtain the ionic hydrogel.

[0086] (4) Two carbon cloth electrodes are respectively attached to the two sides of the prepared ionic hydrogel, and then a polyethylene (PE) film with a thickness of 20 μm is covered on the ionic hydrogel with electrodes to assemble the moisture induced power generation device proposed in the comparative example; the electrode between the polyethylene film and the ionic hydrogel is the positive electrode, the bottom electrode is the negative electrode, and the thickness of the ionic hydrogel is 2 mm.

[0087] Compared with the embodiment, the moisture-induced power generation device obtained in Comparative Example 1 does not have a porous radiation cooling top layer, and cannot regulate the adsorption-desorption process of the ion hydrogel through the radiation cooling effect. Its moisture power generation output performance in outdoor environment is significantly affected by solar radiation fluctuations.

[0088] 2. Wet gas power generation performance test

[0089] The conductive copper tape is used as a wire to connect to the positive and negative electrodes of the wet gas power generation device prepared in the embodiment of the present invention, and is connected to an external circuit data acquisition system (brand: Keysight Technologies, model: DAQ970A) to measure the voltage and current signals. The device is then placed in a constant temperature and humidity test box (brand: Shanghai Yiheng, model: LHS-250HC) to test the power generation performance of the wet gas power generation device prepared in the embodiment under a specific environment.

[0090] Figure 4 This is a test chart showing the output performance of the wet gas power generation device in the embodiment of the present invention as a function of temperature; the introduction of lithium chloride in the ionic hydrogel gives the hydrogel excellent antifreeze performance and water retention capacity, enabling the wet gas power generation device prepared in the embodiment to operate in a wide temperature range of -20 to 50°C. In addition, due to the increase in ion transmission rate at higher temperatures, the short-circuit current output shows a trend of gradually increasing as the temperature rises.

[0091] Figure 5 This is a test chart showing the output performance of the wet gas power generation device according to the embodiment of the present invention as the humidity changes. With the increase of relative humidity (RH), the device open circuit voltage and short circuit current output both show a trend of increasing first and then decreasing. Even at a low humidity of 20%, the device can output an open circuit voltage of 0.41V, and reach a maximum output of ~0.88V at a relative humidity of 70%. The current output shows a high sensitivity to changes in relative humidity, from 1.5μA cm at a relative humidity of 20% to 1.5μA cm at a relative humidity of 20%. -2 It quickly increases to 69 μA cm at 40% -2 , and reaches 306μAcm at 70% -2 The increase in open circuit voltage and short circuit current output is mainly attributed to the efficient moisture adsorption at high relative humidity, which promotes the dissociation and rapid migration of ions. However, too high humidity may hinder moisture evaporation, resulting in reduced output.

[0092] Figure 6 This is a test diagram of the voltage and current of the wet gas power generation device according to the embodiment of the present invention changing with the load resistance value; the wet gas power generation device is connected to an adjustable resistance box, and the load resistance value is changed. When the resistance increases from 0.1Ω to 500MΩ, the voltage across the device gradually increases, and the current gradually decreases. At ~9kΩ, 51.5μW cm -2 The maximum power output. The continuous electrical output of the wet gas power generation device of this embodiment can be attributed to the continuous flow of water driven by the adsorption-desorption dynamic equilibrium, while the efficient output performance depends on strong water adsorption capacity and rapid ion transport. Specifically, polyvinyl alcohol and cyclohexanehexol phosphate as cross-linking points establish a polymer skeleton, and the abundant nanochannels in the hydrogel provide a pathway for the directional transport of water and ions; when interacting with water molecules, cyclohexanehexol phosphate can dissociate a large number of mobile ions, resulting in effective charge separation and an increase in voltage output; the introduction of lithium chloride significantly improves the hygroscopicity of the hydrogel, enabling it to spontaneously collect moisture from the atmosphere and quickly establish a gradient of water content and ion concentration; in addition, since the strong hydration of lithium ions can effectively hinder the formation of hydrogen bonds during freeze-thaw, it helps to increase the ion transfer rate. Therefore, the ionic hydrogel prepared in this embodiment has a small internal resistance and a high ionic conductivity, ensuring the high efficiency of wet gas power generation output.

[0093] Figure 7 The figure is a comparison of the outdoor output sustainability of the wet gas power generation devices manufactured in the embodiment of the present invention and the comparative example; the wet gas power generation devices manufactured in the embodiment and the comparative example were subjected to a 6-day outdoor output performance test, and a weather station was used to record the environmental parameters (temperature, relative humidity and solar radiation intensity) during the outdoor experiment in real time. Figure 7 As shown, the wet gas power generation prepared in the embodiment exhibits self-sustaining and efficient power output for a long time without being affected by fluctuations in environmental conditions. During the day, the graded porous polymer top layer reduces the evaporation temperature through radiation cooling and provides appropriate mass transfer resistance to prolong the evaporation process, thereby maintaining continuous directional water and ion flow. In contrast, although the wet gas power generation device prepared in the comparative example initially exhibits higher output driven by absorbed solar radiation, its output decays more significantly as the water content and evaporation rate decrease. In addition, the graded porous polymer top layer emits thermal radiation to the universe (~3K) at night, effectively offsetting the heat of moisture adsorption, increasing the local relative humidity, and promoting moisture adsorption and recovery of the moisture gradient. Since the wet gas power generation device manufactured in the comparative example cannot regulate the adsorption-desorption process of the ionic hydrogel through the radiation cooling effect, its nighttime regeneration rate is slow, and the voltage and current output gradually decay over multiple day and night cycles.

[0094] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A self-sustaining high-efficiency moisture-induced power generation device assisted by radiation cooling, characterized in that: The self-sustaining high-efficiency moisture-induced power generation device comprises a hydrophobic porous polymer radiation cooling top layer, a hydrophilic ion hydrogel bottom layer, and electrodes disposed on both sides of the hydrophilic ion hydrogel bottom layer; The hydrophilic ionic hydrogel bottom layer can spontaneously absorb moisture in the air and dissociate ions; The hydrophobic porous polymer radiative cooling top layer allows the evaporating vapor to pass through and can regulate the rate of moisture migration and affect the adsorption temperature of the bottom layer components; The hydrophilic ion hydrogel bottom layer is composed of polyvinyl alcohol, cyclohexanehexol phosphate and lithium chloride, and can spontaneously absorb moisture from the air and provide dissociated charge carriers and ion transmission paths for power generation.

2. A radiation cooling assisted self-sustaining high-efficiency moisture induced power generation device according to claim 1, characterized in that: The method for preparing the hydrophobic porous polymer radiation cooling top layer comprises: The polymer powder, acetone and deionized water were mixed and then stirred well at room temperature to prepare a precursor solution; Immersing the template in the precursor solution to evenly coat the polymer solution on the surface of the template, and then taking it out and drying it naturally; The dried coated template was immersed in a hydrochloric acid solution. After the template was completely dissolved, it was placed in ethanol for ultrasonic treatment to remove the residual hydrochloric acid solution, and then dried to obtain a radiation cooling polymer top layer with a hierarchical porous structure.

3. A self-sustaining high-efficiency moisture-induced power generation device assisted by radiation cooling according to claim 2, characterized in that: The polymer material is selected from any one of vinylidene fluoride-hexafluoropropylene copolymer, polyvinylidene fluoride, polymethyl methacrylate, and cellulose acetate.

4. The self-sustaining high-efficiency moisture-induced power generation device assisted by radiation cooling according to claim 1, characterized in that: The preparation method of the hydrophilic ion hydrogel bottom layer comprises: Add lithium chloride to deionized water and stir until completely dissolved; Add polyvinyl alcohol and cyclohexanehexol phosphate to the lithium chloride aqueous solution, and stir them fully in an oil bath to completely dissolve them to obtain a mixed solution; Ultrasonic treatment is performed on the mixed solution to fully remove bubbles in the solution, and the mixed solution after ultrasonic treatment is poured into a mold; The mold containing the mixed solution is frozen, then thawed and demolded at room temperature to obtain the ionic hydrogel.

5. A method for preparing a self-sustaining high-efficiency moisture-induced power generation device assisted by radiation cooling as claimed in claim 1, characterized in that: The following steps are involved: A hydrophobic porous polymer radiative cooling top layer having high solar reflectivity and high infrared emissivity and allowing vapor to pass through is prepared by: Mixing polymer powder, acetone, and deionized water in a preset ratio and stirring to obtain a precursor solution; The hydrophobic porous polymer radiation cooling top layer is obtained by impregnating the precursor solution with the template, drying, acid dissolving the template, ultrasonic cleaning and drying again; The steps of preparing a hydrophilic ionic hydrogel bottom layer comprising polyvinyl alcohol, cyclohexane hexyl phosphate and lithium chloride and having the ability of hygroscopicity, ion dissociation and ion transport are as follows: Dissolve lithium chloride in water; Add polyvinyl alcohol and cyclohexane hexyl phosphate and stir to dissolve in an oil bath; After ultrasonic degassing, the mixture is poured into a mold, and the ionic hydrogel is obtained through freezing, thawing and demoulding; The positive electrode and the negative electrode are respectively attached to the two sides of the hydrophilic ion hydrogel bottom layer, and the hydrophobic porous polymer radiation cooling top layer is placed above the positive electrode, and pressed and assembled to form a self-sustaining high-efficiency moisture-induced power generation device assisted by radiation cooling.

6. The method for preparing a self-sustaining high-efficiency moisture-induced power generation device assisted by radiation cooling according to claim 5, characterized in that: During the preparation of the precursor solution, the mass ratio of polymer powder, acetone and deionized water is 1:8:1, and the stirring time is 30-60 minutes.

7. The method for preparing a self-sustaining high-efficiency moisture-induced power generation device assisted by radiation cooling according to claim 5, characterized in that: The template is a 2mm thick nickel foam, which is immersed in a 1mol / L hydrochloric acid solution for 72-96 hours, ultrasonically treated in ethanol for 15-20 minutes, and dried in a 50°C drying oven for 2-3 hours.

8. The method for preparing a self-sustaining high-efficiency moisture-induced power generation device assisted by radiation cooling according to claim 5, characterized in that: When preparing the hydrophilic ionic hydrogel bottom layer, lithium chloride was stirred at room temperature for 30 minutes until it was completely dissolved, and polyvinyl alcohol and cyclohexanehexol phosphate were added and stirred in a 95° C. oil bath for 3-4 hours.

9. The method for preparing a self-sustaining high-efficiency moisture-induced power generation device assisted by radiation cooling according to claim 8, characterized in that: The mass concentration of the polyvinyl alcohol in the whole liquid is 10wt%, the mass concentration of the lithium chloride in the whole liquid is 5-20wt%, and the mass concentration of the cyclohexanehexanol phosphate in the whole liquid is 7-22wt%.

10. The method for preparing a self-sustaining high-efficiency moisture-induced power generation device assisted by radiation cooling according to claim 5, characterized in that: The thickness of the hydrophilic ion hydrogel bottom layer is 0.5-2 mm, which can be adjusted by using molds with different thicknesses.

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