Moisture-driven generator with core-shell structure and preparation method thereof

Abstract

The invention discloses a moisture-driven generator with a core-shell structure and a preparation method thereof, the moisture-driven generator enables adsorption, diffusion and charge conduction of moisture to be more efficient through the synergistic effect of the core-shell structure, an extra potential difference generated by interaction of built-in potential and the moisture enhances directional movement of charges in a core layer aggregate, and therefore the moisture-driven generator with the core-shell structure is more efficient in adsorption, diffusion and charge conduction. The power generation efficiency is improved; the porous material of the core layer has a stable structure, and the shell layer is firmly wrapped on the surface of the core layer through a complex coacervation method; through the tight combination mode, the core-shell structure can be kept stable in different humidity environments and external physical conditions, and can adapt to various complex application scenes.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wet gas engine, in particular to a wet gas driven generator with core-shell structure and a preparation method thereof. BACKGROUND

[0002] The demand for clean energy is growing today, and wet gas driven generators, as a new energy conversion device, are gradually attracting widespread attention. The principle of wet gas driven power generation is based on the charge transfer of certain materials during the process of moisture absorption and desorption, thereby realizing the conversion of electric energy. As a new humidity gradient energy conversion device, the wet gas driven generator can directly utilize the moisture fluctuations widely existing in the atmospheric environment for power generation, showing unique advantages of all-weather operation and zero carbon emission, and has important application prospects in wearable electronics, environmental monitoring and other fields. However, in the current field, the power generation system is mainly based on ion gradient diffusion, redox couple migration and triboelectricity, but still faces three technical bottlenecks in practical application: First, the energy conversion efficiency is low. The existing technology mainly uses the moisture absorption and expansion effect of single active materials (such as graphene oxide, nanocellulose or MXene) to induce surface charge separation through material volume deformation. However, due to the inherent characteristics of the material, this single driving mechanism leads to an output voltage generally lower than 0.1V, and the power density is difficult to break through the μW / cm² level. For example, a wet gas generator based on graphene can only generate about 50mV of transient voltage under a 65% humidity change, which cannot meet the power supply demand of microelectronic devices.

[0003] Second, the structural stability is insufficient. Although the heterojunction structure design (such as GO / MXene layered composite) can improve the initial output performance through the difference in work function, the physical bonding interface between different material layers is prone to swelling stress mismatch in repeated moisture absorption-desorption cycles. Experiments show that the interface bonding strength of a typical heterojunction generator decreases by 60% after 200 continuous cycles, resulting in more than 40% attenuation of output performance, which seriously restricts the service life of the device.

[0004] Third, the synergy of multiple physical fields is missing. The existing system mainly focuses on a single energy conversion mechanism and fails to effectively integrate the synergistic enhancement effects of charge separation, ion migration and structural deformation. Theoretical calculations show that the upper limit of the energy conversion efficiency of a single mechanism is only 0.3%, and the experimental system is generally less than 1 / 10 of this value. This mechanism fragmentation leads to slow response speed of the device (typical response time > 30s), and the output stability is significantly affected by environmental fluctuations (humidity sensitivity coefficient up to 0.15mV / %RH).

[0005] Therefore, it is necessary to develop a new type of wet gas driven generator and a preparation method thereof to improve the power generation efficiency and output stability. SUMMARY

[0006] The present application aims to provide a novel moisture-driven generator to improve the power generation efficiency and output stability, and to promote the application prospect of the moisture-driven generator.

[0007] Therefore, the present application provides the following solutions: The first aspect of the present application provides a moisture-driven generator, which has a core-shell structure, wherein the core layer comprises an in-built potential material and a condensate formed by oppositely charged polyelectrolytes, and the shell layer is a hydrophobic porous material.

[0008] Further, the condensate is obtained by complex condensation of a positively charged polyelectrolyte and a negatively charged polyelectrolyte; the positively charged polyelectrolyte is selected from polyethyleneimine and / or polydiallyldimethylammonium chloride; and the negatively charged polyelectrolyte includes but is not limited to polystyrene sulfonic acid and / or polyacrylic acid.

[0009] Further, the in-built potential material is selected from a conductive oxide film and / or an ionic conductive compound; the conductive oxide film is preferably an indium tin oxide film deposited on the surface of the condensate; and the ionic conductive compound is preferably a lithium salt such as lithium fluoride or other lithium-containing fluorine salt introduced into the interior of the condensate.

[0010] Further, the condensate contains an added conductive material, one-dimensional nanofiber or nanoparticle, the one-dimensional nanofiber material including but not limited to carbon nanotubes, and the nanoparticle including but not limited to graphene quantum dots.

[0011] Further, the hydrophobic porous material is an oily polymer material, including but not limited to any one or more of acrylate, acrylonitrile, acrylamide, polytetrafluoroethylene, polypropylene, polystyrene or maleic anhydride as a monomer, or a copolymer composed of any two or more monomers.

[0012] Further, the shell layer has a porosity of 30%-80%.

[0013] Further, the shell layer has a pore size distribution of 0.1-5 μm.

[0014] Further, the shell layer has a thickness of 20-100 μm.

[0015] The second aspect of the present application provides a preparation method of the core-shell structure moisture-driven generator of the first aspect, comprising the following steps: S1. Preparing the condensate by a solvent method; S2. Introducing the in-built potential material into the interior or surface of the condensate to obtain the core layer; S3. Spraying a solution of the hydrophobic porous material on the surface of the core layer, and drying to obtain the core-shell structure moisture-driven generator.

[0016] Furthermore, the amount of conductive material added is 1-10% of the mass of the aggregate.

[0017] Furthermore, the process of introducing the built-in potential material into the aggregate is directly based on adding the built-in potential material to the aggregate dispersion prepared by solvent method and then drying it, with the addition amount preferably being 1-5%; the process of introducing the built-in potential material into the surface of the aggregate is based on electrochemical deposition, by depositing a metal oxide film on the surface of the aggregate through electrochemical deposition, with the film thickness preferably being 50-200 nm.

[0018] A third aspect of the present invention is to provide an application of the moisture-driven generator described in the first aspect, or the moisture-driven generator obtained by the preparation method described in the second aspect, wherein the application is to drive power generation in a humid environment, wherein the humid environment is 20%RH or higher.

[0019] A third aspect of the present invention is to provide an electronic device, including an electrical device and a moisture-driven generator as described in the first aspect, or a moisture-driven generator obtained by the preparation method described in the second aspect; the moisture-driven generator provides power to the electrical device.

[0020] Furthermore, the electrical equipment includes wearable electronic products or environmental monitoring products. Wearable electronic products include, but are not limited to, electronic watches, electronic bracelets, and wireless communication products. Environmental monitoring products include, but are not limited to, sensor products used for gas monitoring and water monitoring.

[0021] Compared with the prior art, the present invention has the following beneficial effects: The core-shell structure moisture-driven generator provided by this invention achieves more efficient adsorption, diffusion, and charge conduction of moisture through the synergistic effect of the core and shell structure. The shell layer has a strong adsorption capacity for moisture, enabling rapid introduction of moisture into the core-shell structure. The good conductivity of the core layer facilitates rapid charge transfer. Simultaneously, the additional potential difference generated by the interaction between the nanoparticles with built-in potential and the moisture further increases the directional movement of charge, thereby improving power generation efficiency. Compared with traditional moisture-driven generators, it can generate more electrical energy under the same moisture conditions, significantly improving energy conversion efficiency.

[0022] The core-shell structure moisture-driven generator provided by this invention offers excellent structural stability through its core-shell structure design. The porous material of the core layer itself has a stable structure, while the shell layer is firmly wrapped around the surface of the core layer through a composite condensation method. This tight bonding allows the core-shell structure to remain stable under different humidity environments and external physical conditions. Whether operating for extended periods in high humidity environments or subjected to a certain degree of external impact or vibration, it can maintain its structural integrity, thereby ensuring its continuous and stable power generation performance and enabling it to adapt to various complex application scenarios.

[0023] The moisture-driven generator described in this invention has excellent moisture adsorption properties due to the polyelectrolyte polymer in the shell layer of the core-shell structure. It can effectively utilize the moisture energy in moisture from any source to generate electricity, which has greater flexibility and versatility and can be applied in more fields, further expanding the application scope of moisture-driven power generation technology. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the core-shell structure moisture-driven generator described in this invention. Detailed Implementation

[0025] The technical solution of the present invention will now be clearly and completely described in conjunction with preferred embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] In one embodiment, a method for fabricating a core-shell structure moisture-driven generator is proposed, comprising the following steps: S1. Agglomerates were prepared by solvent method, and conductive materials were added to obtain agglomerate premix; S2. A core layer is obtained by introducing a material with built-in potential into the interior and / or surface of the condensate premix; S3. A hydrophobic porous material is sprayed onto the surface of the core layer and dried to obtain a core-shell structure moisture-driven generator.

[0027] A schematic diagram of the core-shell structure moisture-driven generator obtained by the above preparation method is shown below. Figure 1 As shown.

[0028] In the above embodiments, the moisture-driven generator achieves more efficient adsorption, diffusion, and charge conduction of moisture through the synergistic effect of the core-shell structure. The additional potential difference generated by the interaction between the built-in potential and the moisture enhances the directional movement of charges in the core condensate, thereby improving power generation efficiency. The porous material of the core layer itself has a stable structure, while the shell layer is firmly wrapped around the surface of the core layer through a composite condensation method. This tight combination allows the core-shell structure to remain stable under different humidity environments and external physical conditions, enabling it to adapt to various complex application scenarios.

[0029] In a preferred embodiment, polyelectrolytes with opposite charges form dense physical cross-linking points through electrostatic attraction to obtain aggregates, creating a continuous network structure that runs through the entire material. Positively charged polyelectrolytes include, but are not limited to, polyethyleneimine (PEI) and polydiallyldimethylammonium chloride (PDDA), which contain positively charged functional groups such as amino and quaternary ammonium groups; negatively charged polyelectrolytes include, but are not limited to, polystyrene sulfonic acid (PSS) and polyacrylic acid (PAA), which contain negatively charged functional groups such as sulfonic acid and carboxyl groups. In positively charged polyelectrolytes such as polyethyleneimine (PEI), the protonation degree of the amino groups is significantly affected by pH. When the solution pH is below the isoelectric point of PEI, the amino groups readily bind to hydrogen ions in the solution, resulting in a high degree of protonation and making PEI positively charged overall. As the pH increases and exceeds the isoelectric point, the amino groups gradually deprotonate, weakening the positive charge and potentially even becoming negatively charged. Similarly, in negatively charged polyelectrolytes such as polyacrylic acid (PAA), the carboxyl groups exist in ionization equilibrium in solution. When the pH of the solution is higher than the isoelectric point of PAA, the carboxyl groups ionize to a greater extent, releasing more hydrogen ions, and PAA becomes positively or negatively charged. When the pH is lower than the isoelectric point, the ionization of carboxyl groups is inhibited, and the degree of negative charge decreases. By controlling the pH of the polyelectrolyte solution within a suitable range, the polyelectrolyte can be ensured to exhibit the expected positive or negative charge, thereby facilitating the formation of aggregates through electrostatic attraction.

[0030] In the above embodiments, the composite condensed structure significantly enhances the overall stability of the core material and its moisture adsorption capacity (the polar groups of the polyelectrolyte act as strong binding sites, locking water molecules through ion-dipole interactions. X-ray photoelectron spectroscopy confirmed that after water adsorption, the OH bond content on the material surface increased from 12% to 28%, and the binding energy shifted by 0.8 eV, indicating the formation of a stable hydrated layer). During the moisture absorption process, the different materials in the condensed structure interact, and this interaction effectively promotes charge generation and transfer.

[0031] In the above embodiments, the crosslinking density of the aggregate can be precisely controlled by adjusting the polyelectrolyte concentration (typically 0.5-2.0 wt%), and experiments show that the crosslinking density can be increased to 1.5 × 10⁻⁶. 20 bonds / m 3 At that time, the tensile strength of the material increased from 5 MPa to 22 MPa.

[0032] In the above embodiments, the swelling ratio of the cross-linked aggregate decreased from 150% for the uncross-linked material at 90% RH to 45%. Small-angle neutron scattering (SANS) data showed that cross-linking reduced the pore size distribution of the material from 10-50 nm to 5-20 nm, while maintaining a porosity of over 70%.

[0033] In the above embodiments, the hydroxyl (-OH), amino (-NH), and sulfonic acid (-SO3H) groups between the electrolyte chains form multiple hydrogen bonds (bond energies of approximately 10-30 kJ / mol). For example, in the FTIR spectrum at 3200 cm⁻¹... -1 The broad peak at the point confirms the existence of the hydrogen bond network. During the hygroscopic process, some hydrogen bonds reversibly break to accommodate water molecules (1.2 g of water is adsorbed per gram of material), and reform during dehydration, allowing the material to retain 90% of its initial modulus after 100 humidity cycles.

[0034] In the above embodiments, the dynamic breaking and recombination behavior of hydrogen bonds within the condensate can effectively disperse internal stress caused by humidity changes. Atomic force microscopy (AFM) force curves show that the material containing hydrogen bond networks exhibits a 40% increase in energy dissipation efficiency and a 3-fold increase in interfacial crack propagation resistance under pressure.

[0035] In the above embodiments, the polyelectrolyte undergoes phase separation during condensation to form a multi-level structure consisting of micropores (<2nm), mesopores (2-50nm), and macropores (>50nm). BET testing shows that the specific surface area reaches 380m². 2 / g, of which 65% are mesoporous, providing rapid diffusion channels for water molecules. Dynamic vapor adsorption (DVS) data show that when the RH changes stepwise from 30% to 90%, the material reaches adsorption equilibrium in only 120 seconds, which is 60% shorter than that of traditional materials.

[0036] In a preferred embodiment, a certain amount of functional additives, such as nanofibers or particles with high charge mobility, can be added during the above-mentioned composite condensation process to further enhance the core material's ability in charge generation and transport. Nanofibers or particles significantly reduce the charge transport barrier and increase carrier mobility through multiple mechanisms, including conductive network construction, interface energy level modulation, local electric field enhancement, and ion-electron coupling, ultimately achieving efficient energy conversion in a moisture-driven generator. Their synergistic effect can be likened to a "charge highway," optimizing the energy transfer path at the microscopic scale.

[0037] In a preferred embodiment, the built-in potential material is selected from conductive oxide films or ionic conductive compounds; the conductive oxide film is preferably an indium tin oxide film, deposited on the surface of the condensate; the ionic conductive compound is preferably a lithium salt, such as lithium fluoride or other fluorinated lithium salts, introduced into the interior of the condensate. When moisture enters the core layer, based on the charge generated by the composite condensation structure, the built-in potential guides the charge to be transported in a specific direction, thereby improving the charge collection efficiency. This synergistic effect of composite condensation and built-in potential enables the generator to generate electricity more efficiently during the moisture absorption and dehumidification process, and improves the stability of the output power.

[0038] In a preferred embodiment, the hydrophobic porous material is selected from any one or more polymers using poly(methyl methacrylate-co-butyl acrylate) (P(MMA-co-BA)), acrylates, acrylonitrile, acrylamide, polytetrafluoroethylene, polypropylene, polystyrene, or maleic anhydride as monomers, or copolymers composed of any two or more monomers. The shell porosity is 30%-80%, the shell pore size distribution is 0.1-5 μm, and the shell thickness is 20-100 μm. This can be achieved by polymer material spraying. The specific porosity and shell thickness can be controlled by adjusting the spraying amount and polymer concentration.

[0039] The following are preferred embodiments of the present invention. Unless otherwise specified, the reagents involved in the examples are commercially available reagents, and the experimental methods used are techniques that are well known to those skilled in the art.

[0040] Example 1

[0041] Core layer preparation: Poly(acrylic acid) (PAA) was selected as the negatively charged polyelectrolyte and dissolved in an acetate-sodium acetate buffer solution at pH = 4, with a concentration of 0.1 mol / L. Poly(ethyleneimine) (PEI) was selected as the positively charged polyelectrolyte and dissolved in an ammonia-ammonium chloride buffer solution at pH = 9, with a concentration of 0.1 mol / L. The two solutions were mixed at a volume ratio of 1:1 and reacted at 30°C and a stirring speed of 500 rpm for 30 minutes (the pH of the reaction system was between 7.5 and 8.5) to form a composite aggregate. Subsequently, 5% carbon nanotubes (CNTs) were added to the composite aggregate as a functional additive, and stirring was continued for 10 minutes. Vacuum filtration was performed using a polytetrafluoroethylene filter membrane with a pore size of 0.22 μm to remove excess dispersion media (such as unreacted solvent and free small molecules) from the system, retaining the solid fraction. During filtration, a vacuum of 0.08 MPa was maintained until the filtrate drip rate was ≤1 drop / 3 seconds, ensuring that free liquid in the aggregate network structure was fully removed. The filtered solids were transferred to a vacuum drying oven and dried at 60°C and a vacuum of 0.09 MPa for 6 hours. The material was turned over every 2 hours during drying to prevent local agglomeration. Finally, a 100 nm thick indium tin oxide (ITO) film was deposited on the surface of the composite aggregate using electrochemical deposition to form an internal potential.

[0042] Shell preparation: Poly(methyl methacrylate-co-butyl acrylate) (P(MMA-co-BA)) was selected as the shell material and dissolved in toluene at a concentration of 0.2 mol / L. The shell material was sprayed onto the core layer, and after drying, a shell with a thickness of 50 μm, a porosity of 62%, and a pore size distribution of 1-3 μm was formed.

[0043] Example 2

[0044] Core layer preparation: 0.1 mol / L polydiallyldimethylammonium chloride (PDDA, pH=8.0) was selected as the positively charged polyelectrolyte, and 0.1 mol / L polystyrene sulfonic acid (PSS, pH=4.0) was selected as the negatively charged polyelectrolyte. They were mixed at a volume ratio of 1:1 and reacted at 35℃ and a stirring speed of 600 rpm for 25 minutes to form a composite aggregate (the pH of the reaction system was between 6.0 and 6.5). Lithium chloride (LiCl, with an embedded potential material) at 4% of the aggregate mass was added to the composite aggregate dispersion, and after stirring for 5 minutes, carbon nanotubes at 5% of the mass were added, and stirring was continued for 10 minutes. The mixture was then vacuum filtered through a 0.22 μm polytetrafluoroethylene membrane (vacuum degree 0.08 MPa), and the solid was placed in a vacuum drying oven and dried at 60℃ and 0.09 MPa for 5 hours (stirring every 2 hours). An indium tin oxide (ITO) thin film with a thickness of 120 nm was deposited on its surface using an electrochemical deposition method to obtain the core layer.

[0045] Shell preparation: Polypropylene (PP) was selected as the shell material and dissolved in xylene to prepare a 0.22 mol / L solution. The core surface was coated by spraying, and after drying, a shell with a thickness of 45 μm was formed (porosity of 65%, pore size distribution of 1-3 μm).

[0046] Example 3

[0047] Core layer preparation: 0.15 mol / L polyallylamine hydrochloride (PAH, pH=7.5) was selected as the positively charged polyelectrolyte, and 0.15 mol / L polyacrylic acid (PAA, pH=5.0) was selected as the negatively charged polyelectrolyte. They were mixed at a volume ratio of 1:1 and reacted at 30℃ and a stirring speed of 500 rpm for 30 minutes to form a composite aggregate (the pH of the reaction system was between 6.2 and 6.8). Lithium fluoride (LiF, with an embedded potential material) at 2% by mass was added to the composite aggregate dispersion, and after stirring evenly, graphene quantum dots at 5% by mass were added, and stirring was continued for 10 minutes. After vacuum filtration (0.08 MPa), the mixture was vacuum dried at 60℃ for 6 hours. A 150 nm thick ITO film was deposited on the surface using electrochemical deposition to obtain the core layer.

[0048] Shell preparation: Polytetrafluoroethylene (PTFE) dispersion (concentration 0.25 mol / L) was selected as the shell material and sprayed onto the core surface. After drying, a shell with a thickness of 50 μm, a porosity of 70%, and a pore size distribution of 2-4 μm were formed.

[0049] Example 4

[0050] Core layer preparation: 0.12 mol / L polyethyleneimine (PEI, pH=9.0) was selected as the positively charged polyelectrolyte, and 0.12 mol / L polyacrylic acid (PAA, pH=5.5) was selected as the negatively charged polyelectrolyte. They were mixed at a volume ratio of 2:1 and reacted at 28℃ and a stirring speed of 550 rpm for 35 minutes to form a composite aggregate (the pH of the reaction system was between 7.0 and 7.5). Lithium iodide (LiI, an embedded potential material) at 3% by mass was added to the composite aggregate dispersion, and after stirring for 5 minutes, graphene quantum dots at 7% by mass were added, and stirring was continued for 10 minutes. After vacuum filtration (0.08 MPa), the mixture was vacuum dried at 60℃ for 6 hours to obtain the core layer (with an embedded potential material introduced only internally).

[0051] Shell preparation: Acrylonitrile-styrene copolymer (SAN) was dissolved in N,N-dimethylformamide (concentration 0.18 mol / L) and sprayed onto the core surface. After drying, a shell with a thickness of 55 μm, a porosity of 55%, and a pore size distribution of 0.3-1 μm were formed.

[0052] Example 5

[0053] Core layer preparation: 0.12 mol / L polyethyleneimine (PEI, pH=8.5) was selected as the positively charged polyelectrolyte, and 0.12 mol / L polystyrene sulfonic acid (PSS, pH=4.5) was selected as the negatively charged polyelectrolyte. They were mixed at a volume ratio of 1:1 and reacted at 33℃ and a stirring speed of 580 rpm for 28 minutes to form a composite aggregate (the pH of the reaction system was between 6.5 and 7.0). Lithium bromide (LiBr, with an embedded potential material) at 3% by mass was added to the composite aggregate dispersion, and after stirring for 5 minutes, carbon nanotubes at 5% by mass were added, and stirring was continued for 10 minutes. The mixture was then vacuum filtered through a 0.22 μm polytetrafluoroethylene membrane (0.08 MPa vacuum). The solid was placed in a vacuum drying oven and dried at 60℃ and 0.09 MPa for 6 hours (stirring every 2 hours). An indium tin oxide (ITO) film with a thickness of 110 nm was deposited on its surface using electrochemical deposition to obtain the core layer.

[0054] Shell preparation: Polystyrene (PS) was selected as the shell material and dissolved in toluene to prepare a 0.2 mol / L solution. The core surface was coated by spraying, and after drying, a shell with a thickness of 40 μm, a porosity of 67%, and a pore size distribution of 0.8-2.5 μm was formed.

[0055] Example 6

[0056] Core layer preparation: 0.1 mol / L polydiallyldimethylammonium chloride (PDDA, pH=8.2) was selected as the positively charged polyelectrolyte, and 0.1 mol / L polyacrylic acid (PAA, pH=5.2) was selected as the negatively charged polyelectrolyte. They were mixed at a volume ratio of 1:1.1 and reacted at 31℃ and a stirring speed of 650 rpm for 28 minutes to form a composite aggregate (the pH of the reaction system was between 6.3 and 6.8). Lithium nitrate (LiNO3) at 4% of the aggregate mass was added to the composite aggregate dispersion, and after stirring evenly, graphene quantum dots (5-8 nm particle size) at 8% by mass were added, and stirring was continued for 12 minutes. After vacuum filtration (0.08 MPa), the mixture was dried at 60℃ and 0.09 MPa for 5 hours (stirring every 2 hours) to obtain the core layer.

[0057] Shell preparation: Maleic anhydride-methyl acrylate copolymer (mass ratio 3:7) was selected as the shell material and dissolved in ethyl acetate to prepare a 0.22 mol / L solution. Ultrasonic-assisted spraying (350 W power, nozzle distance 12 cm from the core surface, spraying rate 1.2 mL / min) was used on the core surface. After drying, a shell with a thickness of 70 μm, a porosity of 75%, and a pore size distribution of 1.2–3.8 μm was formed.

[0058] Comparative Example 1 (without two different electroactive polyelectrolytes)

[0059] Core layer preparation: Compared with Example 1, only polyethyleneimine (PEI) was dissolved in a pH=9 buffer solution (concentration 0.1mol / L) and directly dried to form aggregates (no composite aggregates). 5% carbon nanotubes were added, and a 100nm ITO film was deposited on the surface.

[0060] Shell preparation: Same as in Example 1, forming a 50 μm thick P (MMA-co-BA) shell.

[0061] Comparative Example 2 (without electrochemically depositing built-in potential)

[0062] Core layer preparation: Same as the polyelectrolyte mixing and carbon nanotube addition steps in Example 1, but without ITO film deposition (no built-in surface potential).

[0063] Shell preparation: Same as in Example 1.

[0064] Comparative Example 3 (without adding built-in potential material)

[0065] Core layer preparation: the same polyelectrolyte mixing and carbon nanotube addition steps as in Example 2, but without depositing an ITO film or introducing lithium salt (no built-in potential material).

[0066] Shell preparation: Same as in Example 1.

[0067] Comparative Example 4 (without adding carbon nanotubes)

[0068] Core layer preparation: Same as the polyelectrolyte mixing and ITO deposition steps in Example 1, but without adding carbon nanotubes (no conductive material).

[0069] Shell preparation: Same as in Example 1.

[0070] Comparative Example 5 (adding graphene quantum dots)

[0071] No graphene quantum dots were added to the core layer; otherwise, it was the same as in Example 3.

[0072] Comparative Example 6 (without shell layer)

[0073] Core layer preparation: The core layer preparation steps are the same as in Example 1 (including polyelectrolyte composite, carbon nanotubes and ITO film), but the shell layer is not prepared.

[0074] Comparative Example 7 (hydrophilic shell layer)

[0075] Core layer preparation: Same as the core layer preparation steps in Example 1.

[0076] Shell preparation: A polyvinyl alcohol (PVA, a hydrophilic material) solution (concentration 0.2 mol / L) was sprayed onto the core surface and dried to form a 50 μm thick shell.

[0077] Test Example

[0078] Performance testing includes output voltage, power density, cycle stability, and response time.

[0079] The testing standards or methods are as follows: 1. Output voltage: Under 65% RH humidity, the open-circuit voltage of the generator was measured using a Keithley 2450 source meter, and the stable value was recorded; 2. Power density: Calculate the ratio of maximum output power to device area by connecting external loads with different resistance values ​​(1kΩ-100MΩ); 3. Cyclic stability: After repeated switching within the 30%-90% RH humidity range (1000 cycles), the output voltage retention rate was tested. 4. Response time: The time from the start of a step change in humidity (30%→90% RH) until the output voltage reaches a stable value.

[0080] The above embodiments and comparative test results are shown in Table 1.

[0081] Table 1:

[0082] As can be seen from the test results in Table 1, Examples 1-6 all exhibit excellent overall performance, with output voltages all above 0.43V, power densities reaching 4.6μW / cm² or higher, performance retention exceeding 85% after 1000 cycles, and response times all controlled within 20s. This fully demonstrates that the core-shell structure design, the condensate formed by oppositely charged polyelectrolytes, the introduction of built-in potential materials, and the selection of hydrophobic porous shells employed in this invention can synergistically improve the power generation efficiency, structural stability, and response speed of the moisture-driven generator, effectively solving the bottleneck problems of existing technologies.

[0083] Comparative Example 1 (composite aggregation without using two polyelectrolytes with different charges): Using only a single polyelectrolyte to form aggregates, the output voltage was only 0.12V, the power density was 1.1μW / cm², the performance retention rate after 1000 cycles was 60%, and the response time was as long as 45s. The performance was significantly worse than that of the examples, indicating that composite aggregates formed by oppositely charged polyelectrolytes through electrostatic attraction are the basis for achieving efficient charge separation and stable structures, and that a single polyelectrolyte cannot construct an effective charge transport network and a stable matrix structure.

[0084] Comparative Example 2 (without electrochemical deposition of built-in potential): Compared to Example 1, the lack of a surface indium tin oxide film resulted in a decrease in output voltage to 0.28V and power density to 2.7μW / cm², indicating a significant performance degradation. This demonstrates that the surface-deposited metal oxide film, as a built-in potential material, can effectively enhance the directional movement of charges and improve charge collection efficiency, which is crucial for improving power generation efficiency.

[0085] Comparative Example 3 (without built-in potential material): Lacking both internal ionic conductive compounds and surface metal oxide films, the output voltage was only 0.18V, and the power density was 1.5μW / cm², making it one of the worst-performing samples among all tested samples. This verifies that built-in potential materials (whether internally introduced ionic compounds or surface-deposited films) are the core factor promoting directional charge migration and improving energy conversion efficiency. The lack of built-in potential leads to disordered charge transport and a sharp decrease in power generation efficiency.

[0086] Comparative Example 4 (without carbon nanotubes): Due to the absence of carbon nanotubes as a conductive material, the power density decreased to 3.0 μW / cm², and the response time increased to 25 s. This indicates that nanofiber-based conductive materials can construct efficient conductive networks, reduce charge transport resistance, and accelerate charge migration, significantly contributing to improved power density and shortened response time.

[0087] Comparative Example 5 (without graphene quantum dots): Compared to Example 3 with graphene quantum dots, the power density decreased to 2.2 μW / cm², and the response time increased to 30 s. This indicates that nanoparticle-based conductive materials can promote charge transport through mechanisms such as enhanced local electric fields. Their absence leads to a decrease in charge migration efficiency, thereby affecting the generator's output performance.

[0088] Comparative Example 6 (without shell): The core layer is directly exposed, and the performance retention rate after 1000 cycles is only 50%, far lower than the 92% of Example 1. This shows that the shell can provide physical protection for the core layer and reduce structural damage to the core layer during humidity cycling, which is the key to maintaining the long-term stable operation of the generator. Without a shell, the structural stability will deteriorate sharply.

[0089] Comparative Example 7 (using a hydrophilic material as the shell): Using hydrophilic polyvinyl alcohol as the shell, the output voltage was 0.15V, the power density was 1.3μW / cm², and the cycle stability was only 55%. Excessive moisture absorption by the hydrophilic shell led to core swelling, disrupting the charge transport path and structural integrity. This demonstrates the importance of a hydrophobic porous shell in regulating the moisture permeation rate and protecting the core structure; the hydrophilic shell could not meet the generator's performance requirements.

[0090] In summary, this invention, through the innovative design of a core-shell structure moisture-driven generator and its fabrication method, successfully overcomes the bottlenecks of existing technologies in terms of energy conversion efficiency, structural stability, and response speed.

[0091] This invention uses a composite condensate formed by oppositely charged polyelectrolytes as the core layer, and constructs a directional charge migration driving force by introducing built-in potential materials (ionic conductive compounds or conductive oxide films), and adds nanofibers / particles to enhance the conductive network; at the same time, it uses a hydrophobic porous polymer as the shell layer to precisely control the moisture adsorption and diffusion rate, forming a synergistic mechanism of "shell mass transfer - core charge separation - potential directional driving".

[0092] Experimental data show that the generator of this invention can output voltage of 0.43-0.55V, power density of 4.6-6.1μW / cm², performance retention rate of over 85% after 1000 humidity cycles, and response time shortened to 10-20s. Compared with traditional technology, it achieves an output efficiency improvement of more than 10 times, a stability improvement of more than 50%, and a response speed improvement of more than 60%.

[0093] This technology not only expands the material system and structural design ideas for moisture-driven power generation, but also provides a brand-new solution for micro power supplies in wearable electronics, environmental monitoring and other fields due to its high efficiency, stability and adaptability to various humidity environments, and has significant scientific value and industrial application prospects.

[0094] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A moisture-driven generator, characterized in that, The drive generator has a core-shell structure. The core layer includes an internal potential material and a condensate formed by polyelectrolytes with opposite charges; the shell layer is a hydrophobic porous material.

2. The moisture-driven generator according to claim 1, characterized in that, The aggregate is obtained by composite aggregation of a positively charged polyelectrolyte and a negatively charged electrolyte; the positively charged polyelectrolyte is selected from polyethyleneimine and / or polydiallyldimethylammonium chloride; the negatively charged polyelectrolyte includes, but is not limited to, polystyrene sulfonic acid and / or polyacrylic acid.

3. The moisture-driven generator according to claim 1, characterized in that, The built-in potential material is selected from conductive oxide films and / or ionic conductive compounds.

4. The moisture-driven generator according to claim 1, characterized in that, The condensate contains conductive materials, including nanofibers or nanoparticles.

5. The moisture-driven generator according to claim 1, characterized in that, The hydrophobic porous material is selected from any one or more polymers with acrylate, acrylonitrile, acrylamide, polytetrafluoroethylene, polypropylene, polystyrene or maleic anhydride as monomers, or copolymers composed of any two or more monomers.

6. The moisture-driven generator according to claim 1, characterized in that, The porosity of the shell is 30%-80%; And / or, the shell pore size distribution is 0.1-5 μm; And / or, the shell thickness is 20-100 μm.

7. The method for preparing the core-shell structure moisture-driven generator according to claim 1, characterized in that the step include: S1. Agglomerates were prepared using a solvent method; S2. A core layer is obtained by introducing a material with built-in potential into the interior or surface of the condensate; S3. A hydrophobic porous material solution is sprayed onto the surface of the core layer and dried to obtain a core-shell structure moisture-driven generator.

8. The preparation method according to claim 7, characterized in that, The amount of conductive material added is 1-10% of the mass of the aggregate; And / or, the process of introducing a built-in potential material onto the surface of the aggregate is based on electrochemical deposition.

9. The application of the moisture-driven generator according to any one of claims 1-6, or the moisture-driven generator obtained by the preparation method according to any one of claims 7-8, characterized in that, The application is to drive power generation in a humid environment, wherein the humid environment is above 20%RH.

10. An electronic device, characterized in that, It includes electrical equipment, and a moisture-driven generator as described in any one of claims 1-6 or a moisture-driven generator obtained by the preparation method described in any one of claims 7-8; the moisture-driven generator provides power to the electrical equipment.

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