Self-gradient hydrogel humidity power generation device for intelligent agriculture and preparation method

Abstract

The invention provides a self-gradient hydrogel humidity power generation device for intelligent agriculture and a preparation method, and belongs to the technical field of humidity power generation, the self-gradient hydrogel humidity power generation device comprises a supporting layer, a first electrode layer, a power generation layer and a second electrode layer, the first electrode layer is arranged on the surface of one side of the supporting layer, and the power generation layer is arranged on the surface of one side, away from the supporting layer, of the first electrode layer; the second electrode layer is arranged on the surface of the side, away from the first electrode layer, of the power generation layer, and multiple sets of through holes are formed in the second electrode layer. Directional migration of water and ions is promoted through a self-gradient structure, efficient and continuous power generation is achieved, a single device can generate 1.68 V voltage, the short-circuit current density reaches 22.1 mA / cm < 2 >, the power density reaches 3.2 mW / cm < 2 >, the continuous power output time is long, and the device has the advantages of being low in material cost, easy to obtain, free of pollution to the human body and the environment and capable of achieving large-scale preparation and has a wide application prospect. The problems that an existing device is high in cost, low in performance output and poor in continuous output capacity are solved.

Description

Technical Field

[0001] This invention relates to the field of humidity power generation technology, and in particular to a self-gradient hydrogel humidity power generation device for smart agriculture and its preparation method. Background Technology

[0002] Energy is the material foundation for human survival and development. Developing sustainable energy technologies is a crucial path to alleviating global energy shortages, and extracting energy from the environment is a promising method to meet decentralized energy demands and promote the transition to a low-carbon economy. The ubiquitous moisture in ambient air provides a natural energy reservoir; energy generation, conversion, and transfer occur during moisture adsorption and desorption. Humidity-based power generation, as an emerging energy conversion technology, aims to utilize atmospheric moisture to generate electricity, providing humanity with an environmentally friendly and sustainable energy source.

[0003] Humidity generator technology primarily relies on the interaction between hygroscopic substances and water molecules in the atmosphere, utilizing the energy released during the phase change of water from gas to liquid to generate electricity. However, the materials used for generating electricity through moisture are relatively limited, mainly consisting of graphene oxide films, organic polymers, protein nanowires, and their composites. These materials are expensive, difficult to obtain, have complex manufacturing processes, and cause environmental pollution. Furthermore, the power generation capacity of a single humidity generator device is insufficient to meet the demands of actual electrical equipment.

[0004] Therefore, there is an urgent need for a humidity power generation device and manufacturing method with high stable power output to make up for the shortcomings of existing humidity power generation. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, the present invention aims to provide a self-gradient hydrogel humidity power generation device and its preparation method for intelligent agriculture. The self-gradient structure promotes the directional migration of water and ions, achieving efficient and continuous power generation. A single device can generate a voltage of 1.68V and a short-circuit current density of 22.1mA / cm². 2 With a power density as high as 3.2 mW / cm³, 2 It has the advantages of long continuous power output time, low material cost, easy availability, no pollution to human body and environment, and large-scale preparation capability, which solves the problems of high cost, low performance output and poor continuous output capability of existing devices.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] A self-gradient hydrogel humidity power generation device for smart agriculture includes, from bottom to top, a support layer, a first electrode layer, a power generation layer, and a second electrode layer. The first electrode layer is disposed on the surface of the support layer on one side, the power generation layer is disposed on the surface of the first electrode layer away from the support layer, and the second electrode layer is disposed on the surface of the power generation layer away from the first electrode layer. The second electrode layer is provided with a plurality of through holes.

[0008] Preferably, the support layer is a flexible material layer, which includes one or more of cotton fabric, polyimide film, polyester fabric or film.

[0009] Preferably, the material of the power generation layer is composed of polymer, carbon material and inorganic salt.

[0010] Preferably, the first electrode layer and the second electrode layer are each independently selected from metal electrodes or carbon-based material electrodes, and the first electrode layer and the second electrode layer are connected by wires, and the wires are externally connected to the detection device.

[0011] Preferably, the material of the metal electrode includes one or more of aluminum, nickel, silver, and copper; the material of the carbon-based electrode includes one or more of conductive carbon and carbon nanotubes.

[0012] The present invention also provides a method for preparing the above-mentioned self-gradient hydrogel humidity power generation device for smart agriculture, comprising the following steps:

[0013] S1. Prepare the support layer by selecting a flexible material and cutting it to the required size;

[0014] S2. A first electrode layer is prepared on one side surface of the support layer, and the electrode material is adhered to the surface of one side of the support layer by screen printing.

[0015] S3. Prepare the power generation layer by mixing a polymer, carbon material and inorganic salt to form a mixed solution, casting the mixed solution into a mold, and heating it to obtain a self-gradient hydrogel. Then, the self-gradient hydrogel is placed on the surface of the first electrode layer away from the support layer.

[0016] S4. Prepare a second electrode layer by selecting an electrode material with several sets of through holes and placing it on the surface of the power generation layer away from the first electrode layer, so that the second electrode layer is bonded to the power generation layer to obtain a self-gradient hydrogel humidity power generation device.

[0017] Preferably, the polymer comprises one or more of polyacrylamide, N,N'-methylenebisacrylamide, glycerol, and sodium dodecyl sulfate.

[0018] Preferably, the carbon material includes one or more of activated carbon, graphene oxide, and carbon black.

[0019] Preferably, the inorganic salt includes one or more of lithium chloride, sodium chloride, calcium chloride, ammonium persulfate, and magnesium chloride.

[0020] This invention also provides an integrated humidity power generation device, which is obtained by integrating multiple self-gradient hydrogel humidity power generation devices as described above through series integration, parallel integration, or series-parallel integration. Specifically, in the series integration method, the first electrode layer of the humidity power generation device is connected to the second electrode layer of an adjacent humidity power generation device through a conductive material such as conductive silver paste, carbon conductive tape, or copper tape; in the parallel integration method, the first electrode layer of the humidity power generation device is connected to the first electrode layer of an adjacent humidity power generation device through a conductive material such as conductive silver paste, carbon conductive tape, or copper tape; and in the series-parallel integration method, after connecting the first electrode layer of the humidity power generation device to the second electrode layer of an adjacent humidity power generation device, the first and second electrode layers at both ends of all the series integrated combinations are then connected through conductive silver paste, carbon conductive tape, or copper tape, respectively.

[0021] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0022] (1) In terms of material selection and environmental friendliness, the power generation layer material of this invention is composed of polymer, carbon material and inorganic salt. Among them, the polymer can be polyacrylamide, the carbon material can be activated carbon, and the inorganic salt can be lithium chloride. These materials are low in cost, easy to obtain, non-toxic and harmless, and do not pollute the human body and the environment. They are in line with the concept of green development and are suitable for agricultural environments in most parts of the world, overcoming the defects of traditional power generation materials that are expensive and pollute the environment.

[0023] (2) The humidity power generation device provided by the present invention consists of a support layer, a first electrode layer, a power generation layer and a second electrode layer from bottom to top. The second electrode layer is provided with several sets of through holes, while the first electrode layer is not. This structure enables the power generation layer to form a concentration gradient with the upper part wet and the lower part dry in a humid environment. After the amide groups and other groups in the gradient hydrogel absorb moisture, they ionize and release mobile ions. Under the action of the concentration gradient, they migrate in a direction, accelerate the accumulation of charge, and realize continuous and efficient power generation. Compared with traditional homogeneous materials, the power generation efficiency is greatly improved.

[0024] (3) Regarding the power generation performance parameters, a single device of this invention can generate a voltage of 1.68V and a short-circuit current density of 22.1mA / cm². 2 With a power density as high as 3.2 mW / cm³, 2 Furthermore, it provides continuous power output for a long time, which can stably power sensors and other equipment in smart agriculture. It also further enhances moisture absorption capacity and ion content, and strengthens voltage and current output.

[0025] (4) The preparation method provided by the present invention is simple and controllable, which is conducive to large-scale production and solves the problems of high cost, low performance output and poor continuous output capability of existing devices. At the same time, the integrated humidity power generation device can be obtained by integrating multiple independent humidity power generation devices through series, parallel or series-parallel connection, which can flexibly improve the output voltage and current to meet different power requirements and provide a feasible solution for large-scale power supply in smart agriculture. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the structure of a self-gradient hydrogel humidity power generation device for smart agriculture according to the present invention.

[0028] Figure 2 This is a test diagram of the power generation performance of the self-gradient hydrogel humidity power generation device provided in Embodiment 1 of the present invention;

[0029] Figure 3 This is a test diagram of the power generation performance of the self-gradient hydrogel humidity power generation device provided in Embodiment 2 of the present invention;

[0030] Figure 4 This is a test diagram of the power generation performance of the self-gradient hydrogel humidity power generation device provided in Embodiment 3 of the present invention;

[0031] Figure 5 This is a test diagram of the power generation performance of the self-gradient hydrogel humidity power generation device provided in Embodiment 4 of the present invention;

[0032] Figure 6 This is a test diagram of the power generation performance of the self-gradient hydrogel humidity power generation device provided in Embodiment 5 of the present invention;

[0033] Figure 7 This is a test diagram of the power generation performance of the self-gradient hydrogel humidity power generation device provided in Embodiment 6 of the present invention;

[0034] Figure 8 Voltage and current test diagrams of the self-gradient hydrogel humidity power generation device under different humidity conditions provided by the present invention;

[0035] Figure 9 Voltage and current test diagrams of the self-gradient hydrogel humidity power generation device at different temperatures provided by the present invention;

[0036] Figure 10The power generation performance test diagram of the self-gradient hydrogel humidity power generation device under long-term operation provided by the present invention;

[0037] Figure 11 The output power test diagram of the self-gradient hydrogel humidity power generation device provided by the present invention;

[0038] Figure 12 A schematic diagram of the scalable integrated self-gradient hydrogel humidity power generation device provided by the present invention;

[0039] Figure 13 Voltage test diagram of the scalable integrated self-gradient hydrogel humidity power generation device provided by the present invention;

[0040] Figure 14 Current test diagram of the scalable integrated self-gradient hydrogel humidity power generation device provided by the present invention;

[0041] Figure 15 A schematic diagram illustrating the application of the self-gradient hydrogel humidity power generation device provided by this invention in smart agriculture;

[0042] Explanation of reference numerals in the attached figures:

[0043] 1. Support layer; 2. First electrode layer; 3. Power generation layer; 4. Second electrode layer; 5. Through hole. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0045] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0046] like Figure 1 As shown, this invention provides a self-gradient hydrogel humidity power generation device for smart agriculture, comprising, from bottom to top, a support layer 1, a first electrode layer 2, a power generation layer 3, and a second electrode layer 4. The first electrode layer 2 is disposed on one side of the support layer 1, the power generation layer 3 is disposed on the side of the first electrode layer 2 away from the support layer 1, and the second electrode layer 4 is disposed on the side of the power generation layer 3 away from the first electrode layer 2. The second electrode layer 4 has several sets of through holes 5. The through holes 5 are 100-200 mesh to ensure that moisture can pass through the second electrode layer 4 into the power generation layer 3.

[0047] In a preferred embodiment, the support layer 1 is a flexible material layer with a thickness of 0.1 to 1 mm to ensure good sealing and flexibility; the flexible material layer includes one or more of cotton cloth, polyimide film, polyester cloth or film.

[0048] In a preferred embodiment, the power generation layer 3 is composed of a polymer, carbon material, and inorganic salt. Specifically, the polymer, carbon material, and inorganic salt are mixed uniformly to obtain a polymer-carbon-inorganic salt solution. This solution is then cast into a mold and heated to 60°C to obtain a self-gradient hydrogel, thus preparing a power generation layer 3 with a thickness of 1–10 mm. The self-gradient hydrogel contains a large number of amide, hydroxyl, and carboxyl groups, enabling it to absorb water molecules in humid environments. Compared to traditional homogeneous materials using isotropic adsorption and diffusion modes, the design of the self-gradient hydrogel facilitates the directional migration of water and ions, thereby accelerating charge accumulation and continuous power generation. After asymmetric water absorption by the upper and lower membranes, the amide, hydroxyl, and carboxyl groups can ionize and move ions, which migrate under the influence of the concentration gradient to generate voltage. Specifically, the second electrode layer 4 has multiple through-holes 5, while the first electrode layer 2 does not. Under humid conditions, the upper surface of the membrane absorbs moisture while the lower surface cannot, resulting in a wet upper surface and a dry lower surface, forming a concentration gradient.

[0049] Furthermore, the polymeric material includes one or more of polyacrylamide, N,N'-methylenebisacrylamide, glycerol, and sodium dodecyl sulfate; the carbon material includes one or more of activated carbon, graphene oxide, and carbon black; and the inorganic salt includes one or more of lithium chloride, sodium chloride, calcium chloride, ammonium persulfate, and magnesium chloride.

[0050] Furthermore, the preparation process of the polymer-carbon-inorganic salt solution is as follows: the polymer, carbon material and inorganic salt are dissolved in water and stirred in a magnetic stirrer at a temperature of 25-40°C and a speed of 500-1000 r / min for 0.5-2 hours to form a transparent and uniform polymer-carbon-inorganic salt solution.

[0051] In a preferred embodiment, the first electrode layer 2 and the second electrode layer 4 are each independently selected from metal electrodes or carbon-based material electrodes. The first electrode layer 2 and the second electrode layer 4 are connected by wires, such as double-sided copper wires, conductive silver paste, or conductive connecting wires, and the wires are externally connected to the detection equipment.

[0052] Furthermore, the material of the metal electrode includes one or more of aluminum, nickel, silver, and copper; the material of the carbon-based electrode includes one or more of conductive carbon and carbon nanotubes.

[0053] The following specific embodiments will further illustrate the above content. The examples listed are only some of the embodiments of the present invention and do not include all the embodiments of the present invention.

[0054] Example 1

[0055] In this embodiment, a method for preparing a self-gradient hydrogel humidity power generation device for smart agriculture is provided, comprising the following steps:

[0056] To prepare the support layer, flexible materials such as polyester film were selected and cut to a thickness of 1 mm.

[0057] A first electrode layer is prepared on one side surface of the support layer, and electrode material is adhered to the surface of one side of the support layer by screen printing. In this embodiment, the first electrode layer is an inert material layer, and the conductive material of the inert material layer is preferably conductive carbon, but it can also be graphene, carbon nanotubes, silver, or gold, etc., with a thickness of 0.3 mm and an area of ​​1 cm². 2 It is adhered to the upper surface of the support layer by screen printing.

[0058] To prepare the power generation layer, a mixed solution is formed by mixing a polymer, carbon material and inorganic salt. The mixed solution is then cast into a mold and heated to obtain a self-gradient hydrogel. Subsequently, the self-gradient hydrogel is disposed on the surface of the first electrode layer away from the support layer.

[0059] Specifically, in this embodiment, glycerol, activated carbon, lithium chloride, and sodium dodecyl sulfonate are dispersed in deionized water, and then a magnetic stirrer is set to a speed of 500 r / min and stirred for 1 hour to obtain a uniformly dispersed solution. Acrylamide, ammonium persulfate, and N,N'-methylenebisacrylamide are then added to the above solution and stirred for another hour to obtain a uniformly dispersed solution. The solution is then cast into a polytetrafluoroethylene mold, placed in an oven at 60°C, and dried for 1 hour to obtain a self-gradient hydrogel. This hydrogel is then transferred to the first electrode layer to obtain the power generation layer.

[0060] A second electrode layer is prepared by selecting an electrode material with several sets of through holes and placing it on the surface of the power generation layer away from the first electrode layer, thereby bonding the second electrode layer to the power generation layer to obtain a self-gradient hydrogel humidity power generation device. In this embodiment, the second electrode layer is a metal material layer, preferably made of aluminum, but also nickel, copper, or silver. The through holes are 100 mesh with an area of ​​1 cm². 2 The power generation layer and the second electrode layer are directly pressed and bonded together, while the through holes ensure that moisture enters the power generation layer through the second electrode layer.

[0061] The power generation performance of the device in this embodiment was tested, and the test results are as follows: Figure 2As shown, the results indicate that the device's voltage output stabilizes at 1.68V through the synergistic incorporation of glycerol, activated carbon, and lithium chloride; the current density exhibits significant differences under varying humidity conditions. Specifically, the short-circuit current density reaches 14.1 mA / cm² under 50% RH conditions. 2 The short-circuit current density was further increased to 22.1 mA / cm² under high humidity conditions of 80% RH. 2 The power density reaches 3.2 mW / cm². 2 This performance is attributed to the moisturizing properties of glycerol, the adsorption-enhancing effect of activated carbon, and the high ion dissociation characteristics of lithium chloride. These three factors work synergistically to promote the directional migration of ions and charge accumulation in the self-gradient hydrogel, enabling the device to achieve efficient and stable power generation in agricultural environments with varying humidity levels.

[0062] Example 2

[0063] This embodiment provides a method for preparing a self-gradient hydrogel humidity power generation device for smart agriculture. The overall steps are the same as in Embodiment 1, including the preparation of a support layer, the preparation of a first electrode layer, the preparation of a power generation layer, and the preparation of a second electrode layer. Each layer is the same as in Embodiment 1. The main difference is that the type of inorganic salt is changed in the preparation of the power generation layer, that is, lithium chloride is replaced with calcium chloride, magnesium chloride, sodium chloride, or zinc chloride.

[0064] Specifically, in preparing the power generation layer, this embodiment replaces the lithium chloride in Example 1 with an equal mass of calcium chloride, while keeping the other raw materials and proportions unchanged: glycerol, activated carbon, calcium chloride, and sodium dodecyl sulfonate are dispersed in deionized water and stirred at 500 r / min for 1 hour; then acrylamide, ammonium persulfate, and N,N'-methylenebisacrylamide are added and stirred for another hour to obtain a uniform mixed solution; the solution is cast into a polytetrafluoroethylene mold and heated in a 60°C oven for 1 hour to form a self-gradient hydrogel, which is then placed on the surface of the first electrode layer.

[0065] This embodiment modifies the type of inorganic salt, utilizing calcium chloride, which is cheaper, non-toxic, and biodegradable than lithium chloride. Calcium chloride, due to its high hygroscopic capacity and ion migration efficiency, can achieve higher power density output in humidity gradient power generation. This embodiment can also replace lithium chloride in Example 1 with magnesium chloride, utilizing its dissociation characteristics in hydrogels—its ion mobility is slightly lower than lithium chloride but its stability is higher—to enable the device to exhibit superior performance stability in agricultural environments with large temperature fluctuations. Simultaneously, lithium chloride can be replaced with sodium chloride, as sodium chloride has moderate ion dissociation, making the device stable in moderate humidity field environments. Finally, this embodiment can also replace lithium chloride with zinc chloride, which has strong ionic conductivity, enabling the device to achieve an output voltage of 1.60V and a short-circuit current density of 2.3mA / cm². 2However, its hygroscopicity is slightly lower than that of lithium chloride, making it more suitable for agricultural scenarios in arid regions with low humidity.

[0066] The power generation performance of devices prepared with different inorganic salts in this embodiment was tested, and the test results are as follows: Figure 3 As shown, the results indicate that under the same experimental conditions, different chloride salts have little effect on the voltage output of the device, but a significant effect on the short-circuit current. Specifically, the device using lithium chloride (LiCl) from Example 1 still exhibits the best current output performance, with a significantly higher short-circuit current density than the calcium chloride, magnesium chloride, sodium chloride, and zinc chloride groups. This difference stems from the stronger ion dissociation ability and water absorption of lithium chloride, which makes it easier to form a stable ion migration gradient in the self-gradient hydrogel, thereby promoting more charge accumulation under the same humidity conditions.

[0067] Example 3

[0068] This embodiment provides a method for preparing a self-gradient hydrogel humidity power generation device for smart agriculture. The overall steps are the same as in Embodiment 1, including the preparation of a support layer, the preparation of a first electrode layer, the preparation of a power generation layer, and the preparation of a second electrode layer. Each layer is the same as in Embodiment 1. The main difference is that the amount of activated carbon is increased in the preparation of the power generation layer.

[0069] Specifically, in preparing the power-generating layer, this embodiment increases the amount of activated carbon used in Example 1: glycerol, the adjusted amount of activated carbon, lithium chloride, and sodium dodecyl sulfonate are dispersed in deionized water according to a specific ratio and stirred for 1 hour; then acrylamide, ammonium persulfate, and N,N'-methylenebisacrylamide are added and stirring continues for 1 hour to obtain a homogeneous mixed solution; after casting and heating to form a self-gradient hydrogel, it is placed on the surface of the first electrode layer. By increasing the amount of activated carbon, its larger specific surface area enhances its adsorption capacity for water and ion adsorption, accelerating charge transfer efficiency.

[0070] The power generation performance of devices with different activated carbon dosages was tested, and the test results are as follows: Figure 4 As shown, the results indicate that the amount of activated carbon has a significant impact on the device's current output. As the amount increases from 5 wt% to 9 wt%, the short-circuit current initially increases and then decreases. Specifically, the device achieves optimal performance when the activated carbon content is 7 wt%, with the short-circuit current density increasing by 12% compared to 5 wt%, while the voltage remains stable at around 1.65 V. However, when the content exceeds 7 wt%, the excessive activated carbon leads to an overly dense pore structure within the hydrogel, hindering directional ion migration and causing an 8% decrease in current density. This result demonstrates that a 7 wt% activated carbon content can maximize the synergistic effect of adsorption and conductivity while ensuring unobstructed ion migration channels, making it suitable for most humidity-fluctuating environments in agriculture.

[0071] Example 4

[0072] The difference between this embodiment and Embodiment 1 is that only the thickness (1-10 mm) of the material cast into the polytetrafluoroethylene mold is changed. Everything else is the same as in Embodiment 1. By increasing the thickness of the power generation layer, the diffusion path of moisture and the migration distance of ions in the hydrogel are extended, thereby enhancing the charge accumulation effect.

[0073] Performance tests were conducted on devices with power generation layers of different thicknesses, and the test results are as follows: Figure 5 As shown, the results indicate that the hydrogel thickness significantly affects the device's current output. As the thickness increases from 2 mm to 8 mm, the short-circuit current exhibits a trend of first increasing and then decreasing. Specifically, the device achieves optimal performance at a thickness of 4 mm, with the short-circuit current density increasing by 18% compared to 2 mm, and the voltage remaining stable at around 1.70 V. However, when the thickness exceeds 4 mm, the excessively thick hydrogel leads to a longer moisture diffusion path and increased resistance to ion migration, causing the current density to decrease by 15% compared to 4 mm. This result demonstrates that a 4 mm power generation layer thickness achieves an optimal balance between moisture adsorption efficiency and ion migration resistance, making it suitable for the humidity conditions in most agricultural scenarios.

[0074] Example 5

[0075] The difference between this embodiment and Embodiment 1 is that only the area (0.16–16 cm²) of the material cast into the PTFE mold is changed. 2 The rest is the same as in Example 1. By increasing the area of ​​the power generation layer, the contact area with ambient moisture is increased, thereby improving the total amount of ion migration.

[0076] Performance tests were conducted on devices with different areas of power generation layers, and the test results are as follows: Figure 6 As shown, the results indicate a significant positive correlation between the area of ​​the power generation layer and the device's output current. Specifically, when the area increases from 0.16 cm², the output current increases significantly. 2 Gradually expand to 16cm 2 At that time, the device output current increased linearly from 1.11mA to 76.55mA, while the voltage remained stable at around 1.68V. This phenomenon is due to the fact that as the area is increased, the contact area between the power generation layer and the ambient moisture increases synchronously, the total amount of ion migration increases accordingly, and the uniformity of the self-gradient structure ensures the stability of the performance per unit area.

[0077] Example 6

[0078] The difference between this embodiment and Embodiment 1 lies in the use of different electrodes (nickel, copper, and silver) in the second electrode layer. Everything else is the same as in Embodiment 1. Nickel mesh electrodes offer superior corrosion resistance compared to aluminum electrodes, reducing electrode oxidation loss in high-humidity, high-salt agricultural environments. Furthermore, replacing the nickel mesh in this embodiment with copper or silver mesh of equal specifications achieves similar results: copper mesh electrodes are less expensive than nickel mesh electrodes, making them suitable for low-cost, large-scale applications; silver mesh electrodes offer better conductivity, increasing output current density.

[0079] Performance tests were conducted on devices using different electrode materials, and the test results are as follows: Figure 7 As shown, the results indicate that, under the same experimental conditions, the device using an aluminum mesh as the second electrode exhibits the best performance. Specifically, its output voltage is stably maintained at 1.68V, and its short-circuit current density reaches 22.1 mA / cm². 2 This significantly outperforms devices with nickel, copper, and silver mesh electrodes. This result stems from the better-matched interfacial contact characteristics between the aluminum mesh and the self-gradient hydrogel power generation layer, as well as the synergistic effect of the electrode redox reaction. This ensures that moisture can efficiently enter the power generation layer through the vias while reducing interfacial impedance during charge transport, thus achieving an optimal balance between voltage stability and current output efficiency.

[0080] In addition, to further verify the performance stability of the self-gradient hydrogel humidity power generation device of the present invention under different humidity environments, the voltage performance of the device prepared in Example 1 was tested under different humidity conditions, and the results are as follows. Figure 8 As shown, the open-circuit voltage of the device remains stable at around 1.67V within a relative humidity range of 20% to 98%. This stability stems from the dynamic moisture regulation capability of the self-gradient hydrogel: at low humidity, the hydrogel maintains the moisture required for ion migration through the strong adsorption force of polar groups; at high humidity, excess moisture diffuses naturally through the gradient structure, avoiding dilution of ion concentration, thereby maintaining a stable charge accumulation efficiency within different humidity ranges.

[0081] Subsequently, during the tests within the aforementioned humidity range, the changes in the short-circuit current of the device were monitored simultaneously, and the results are as follows: Figure 8 As shown, the current initially increases and then decreases with humidity, reaching its optimal state at 80% RH. This is because in the low humidity stage (20%–80% RH), as the ambient humidity increases, the number of water molecules adsorbed by the hydrogel through polar groups (amide groups, hydroxyl groups) increases, promoting the dissociation of inorganic salts into more mobile ions. Driven by the concentration gradient, the directional migration rate accelerates, leading to a continuous increase in current. However, when the humidity exceeds 80% RH, the excess water dilutes the ion concentration inside the hydrogel, and the driving force of ion migration in the gradient structure weakens, resulting in a slight decrease in current.

[0082] To further verify the adaptability of the self-gradient hydrogel humidity power generation device of the present invention to extreme temperature environments, the device prepared in Example 1 was subjected to performance tests at different temperatures, and the results are as follows: Figure 9 As shown. In Figure 9 In voltage stability tests, the open-circuit voltage remained stable at around 1.62V at -40℃. This is attributed to the antifreeze properties of glycerol in the hydrogel, which prevents ion migration channels from being blocked by freezing at low temperatures. Figure 9 In the current output test, the device's output current first increased and then decreased with temperature, reaching its optimal value at 60℃. This is because the thermal motion of ions is slow at low temperatures, limiting the current; at 60℃, the ion dissociation and migration rates reach an optimal balance, resulting in the best current performance; after the high temperature exceeds the thermal stability threshold of the hydrogel, the degradation of some polymer chain segments leads to damage to the ion channels, causing the current to decrease accordingly.

[0083] After verifying the device's temperature adaptability, its long-term operational stability, power output characteristics, and scalable integration potential were further tested, and the results are as follows: Figure 10 , Figure 11 As shown. (Refer to...) Figure 10 The device maintained a voltage of 1.08V after more than 740 hours of continuous operation, approximately 64.26% of its initial peak voltage. This is because the three-dimensional network formed by the polymer effectively suppressed moisture evaporation and ion loss, while the synergistic effect of the carbon material and inorganic salt maintained long-term ion migration capability. (Reference) Figure 11 The output voltage of the device initially increases and then decreases with increasing load resistance. When the load resistance is 300Ω, the device can achieve 3.23mW / cm². -2 Peak output power density.

[0084] To further achieve higher power output to adapt to large-scale agricultural scenarios, this invention also proposes a scalable device fabrication scheme, such as... Figure 12 As shown, the device employs laser processing of an aluminum mesh to fabricate a second electrode array, template casting to prepare a hydrogel power generation layer array, and screen printing of conductive carbon ink onto a polyester film to form highly conductive carbon electrodes as the first electrode array. Multiple device units are then integrated in series and / or parallel to form a modular power system. Experiments have shown that this invention can scalably integrate self-gradient hydrogel devices, integrating 870 device units over a large area (186cm × 30cm).

[0085] Based on the proposed scalable device fabrication scheme, the voltage and current output performance of the integrated device were further tested, and its application value was verified. The results are as follows: Figure 13 , Figure 14 and Figure 15 As shown. (Refer to...) Figure 13Series integration testing was performed on the device described in Example 1. The results showed that the output voltage of the integrated MEG increased linearly with the number of series units, reaching approximately 192V with 100 series devices. This characteristic stems from the superposition effect of the voltages of each unit in the series structure, and the uniformity of the self-gradient hydrogel ensures no significant voltage loss. (Refer to...) Figure 14 The current increases linearly with the number of parallel units. When 100 units are connected in parallel, the peak current reaches 398mA.

[0086] like Figure 15 As shown, the self-gradient hydrogel humidity power generation device of the present invention can be integrated through series and parallel connections to achieve diversified power supply in smart agriculture scenarios. Simultaneously, the self-gradient hydrogel humidity power generation device provided by the present invention can also power wireless sensing devices, specifically real-time data acquisition from wireless temperature, humidity, and light sensors, providing data support for adjusting the optimal growth environment for crops; additionally, it can power black lights, with the integrated device generating sufficient power to directly drive a 5W black light, which helps to trap pests in crops.

[0087] Therefore, the self-gradient hydrogel humidity power generation device and its preparation method for intelligent agriculture described above promote the directional migration of water and ions through the self-gradient structure, achieving efficient and continuous power generation. A single device can generate a voltage of 1.68V and a short-circuit current density of 22.1mA / cm². 2 With a power density as high as 3.2 mW / cm³, 2 It has the advantages of long continuous power output time, low material cost, easy availability, no pollution to human body and environment, and large-scale preparation capability, which solves the problems of high cost, low performance output and poor continuous output capability of existing devices.

[0088] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0089] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A self-gradient hydrogel humidity power generation device for smart agriculture, characterized by, The self-gradient hydrogel humidity power generation device comprises a support layer, a first electrode layer, a power generation layer and a second electrode layer from bottom to top, the first electrode layer is arranged on one side of the support layer, the power generation layer is arranged on the side of the first electrode layer away from the support layer, the second electrode layer is arranged on the side of the power generation layer away from the first electrode layer, and a plurality of groups of through holes are arranged on the second electrode layer.

2. The self-gradient hydrogel humidity generator device for intelligent agriculture according to claim 1, characterized in that, The support layer is a flexible material layer, and the flexible material layer comprises one or more of cotton cloth, polyimide film, polyester cloth or film. 3.The self-gradient hydrogel humidity generator for intelligent agriculture of claim 1, wherein, The material of the power generation layer is composed of a high polymer, a carbon material and an inorganic salt. 4.The self-gradient hydrogel humidity generator for intelligent agriculture of claim 1, wherein, The first electrode layer and the second electrode layer are each independently selected from a metal electrode or a carbon-based material electrode, the first electrode layer and the second electrode layer are connected by a wire, and the wire is circumscribed on a detection device. 5.The self-gradient hydrogel humidity generator for intelligent agriculture of claim 4, wherein, The material of the metal electrode comprises one or more of aluminum, nickel, silver and copper; and the material of the carbon-based material electrode comprises one or more of conductive carbon and carbon nanotubes.

6. A method for producing the self-gradient hydrogel humidity generator for smart agriculture according to any one of claims 1 to 5, characterized by, The method comprises the following steps: S1, preparing a support layer, selecting a flexible material and cutting it to a desired size; S2, preparing a first electrode layer on one side of the support layer, and adhering an electrode material to the side of the support layer by silk screen printing; S3, preparing a power generation layer, mixing a high polymer, a carbon material and an inorganic salt to form a mixed solution, pouring the mixed solution into a mold, and obtaining a self-gradient hydrogel after heating treatment, and then arranging the self-gradient hydrogel on the side of the first electrode layer away from the support layer; S4, preparing a second electrode layer, selecting an electrode material provided with a plurality of groups of through holes, arranging the electrode material on the side of the power generation layer away from the first electrode layer, and adhering the second electrode layer to the power generation layer to obtain a self-gradient hydrogel humidity power generation device.

7. The method for preparing a self-gradient hydrogel humidity power generation device for intelligent agriculture according to claim 6, characterized in that, The high polymer comprises one or more of polyacrylamide, N,N'-methylene bisacrylamide, glycerol and sodium dodecyl sulfate.

8. The method for preparing a self-gradient hydrogel humidity power generation device for intelligent agriculture according to claim 6, characterized in that, The carbon material comprises one or more of activated carbon, graphene oxide and carbon black.

9. The method for preparing a self-gradient hydrogel humidity power generation device for intelligent agriculture according to claim 6, characterized in that, The inorganic salt comprises one or more of lithium chloride, sodium chloride, calcium chloride, ammonium persulfate and magnesium chloride.

10. An integrated moisture power generator device, characterized by, A plurality of self-gradient hydrogel humidity power generation devices according to any one of claims 1 to 5 are obtained by series integration, parallel integration or series-parallel integration.

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