A moisture-generating device, its preparation method and application

Abstract

This invention relates to a moisture-generating device, its preparation method, and its application, belonging to the field of moisture-generating technology. The moisture-generating device of this invention includes a flexible substrate, an upper electrode, a lower electrode, and a power-generating active material; the power-generating active material is disposed between the upper electrode and the lower electrode; the power-generating active material has a core-sheath structure, with the sheath layer at the edge being a cross-linked hydrogel structure, and the core layer being a hydrogel precursor solution; the sheath layer restricts the shape of the hydrogel precursor solution in the core layer and is in contact with the atmosphere. The core-sheath structure of the power-generating active material is prepared by a one-step ultraviolet light-induced polymerization / gelation method. The moisture-generating device provided by this invention ensures stable and continuous power output and significantly improved moisture-to-electricity conversion efficiency. Furthermore, its miniaturized design offers significant advantages such as compact structure and ease of integration, and its convenient assembly facilitates large-scale production.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of wetness power generation, in particular to a wetness power generator, a preparation method and application thereof. BACKGROUND

[0002] Due to the bulky and rigid structure of traditional power sources (e.g. batteries), it is difficult to adapt to the rapid development of flexible and wearable electronic technology. Therefore, there is an increasing demand for lightweight, flexible power sources in the market. Such power sources need to be integrated with flexible electronic devices in a low-cost and high-efficiency manner to realize the self-power supply capability of the system. In recent years, through the use of various energy collection and conversion strategies, significant progress has been made in the development of self-powered flexible and wearable electronic devices. Among them, the water vapor-electric energy conversion is realized through a wetness power generator, which uses the moisture widely existing in the environment as energy to generate electricity, and has the advantages of environmental friendliness, low cost, simple device structure and no moving parts, etc., and is therefore considered to have broad prospects in the development of various self-powered, wearable electronic devices.

[0003] A single wetness power generator device is composed of an active material layer and a pair of asymmetric electrodes, and each component plays a different role in promoting the power generation process of the device. Several key factors of the wetness power generation active material layer are crucial to improving the power generation performance: the layer needs to have sufficient moisture absorption capacity, contain abundant positive and negative ion pairs to reduce resistance, and be able to establish and maintain an ion concentration gradient. After capturing water molecules from the environment, the ion pairs in the active layer will undergo hydrolysis and ionization, and at the same time the concentration gradient can drive the migration of charge carriers to generate electric energy. In order to improve the efficiency of water absorption and evaporation, promote directional water transport and enhance ion migration, existing researches strive to construct hybrid / composite active material layers by compounding strong / weak hydrophilic materials and complex preparation processes, to finely regulate their moisture absorption, ionization potential and ion conductivity, thereby significantly improving the overall performance of the power generation device. In recent years, in order to simplify the preparation process, the trend has shifted to using single-layer multifunctional active materials to develop power generation devices with sustained power output, such as protein nanofibers, titanium dioxide, fluorine / oxygen bonded graphene materials, silicon nanowire arrays and metal organic framework compounds. In addition, ion-conducting hydrogels have become an ideal active layer for constructing wetness power generation devices due to their excellent moisture absorption, adjustable composition, convenient preparation process and excellent formability. However, the preparation details of the hydrogel can significantly affect its performance, and as the crosslinking density and aging time increase, the viscosity, physical crosslinking density and crystallinity of the hydrogel also increase, leading to a decrease in its ion conductivity and water absorption capacity, thereby significantly reducing the power generation performance of the device. Therefore, using a single hydrogel as the active layer is not the best strategy to optimize the power performance of the wetness power generation device. Of course, the precursor solution before gelation, although it has higher ion conductivity, cannot be used directly due to its fluidity. SUMMARY

[0004] To address the aforementioned technical problems, this invention proposes a moisture-generating device, its preparation method, and its application. Specifically, it describes the preparation of a hydrogel-based moisture-generating device via a one-step ultraviolet curing method, and its application in a self-powered wearable sensor. Its power-generating active material has a "core-sheath" structure, comprising a core layer of a hydrogel precursor solution and a sheath layer of ultraviolet-cured hydrogel.

[0005] The moisture-generating device of this invention includes a pair of electrodes arranged vertically, an electrode support structure, and a power-generating active material with a core-sheath structure loaded between the upper and lower electrodes. The shape of the aqueous solution is constrained by an edge-crosslinked hydrogel structure, allowing it to contact the atmosphere. The moisture-generating device provided by this invention employs a miniaturized design, offering significant advantages such as compact structure and ease of integration. Its convenient assembly facilitates large-scale production, while ensuring stable and continuous power output and significantly improved moisture-to-electricity conversion efficiency.

[0006] This invention is achieved through the following technical solution:

[0007] The first objective of this invention is to provide a moisture-generating device, which includes a flexible substrate, an upper electrode, a lower electrode, and a power-generating active material; the power-generating active material is disposed between the upper electrode and the lower electrode; the power-generating active material covers the second electrode;

[0008] The power-generating active material has a core-sheath structure, with the sheath layer at the edge being a cross-linked hydrogel structure and the core layer being a hydrogel precursor solution; under the action of surface tension, the edge of the sheath layer is a meniscus.

[0009] The sheath restricts the shape of the hydrogel precursor solution in the core layer and exposes it to the atmosphere.

[0010] Furthermore, the power-generating active material is prepared by localized ultraviolet light-induced polymerization and gelation of the hydrogel precursor solution. The sheath layer is formed in situ at the edge of the hydrogel precursor solution.

[0011] The carrier mobility of the hydrogel precursor solution is 10. -3 -10 -2 cm² / (V·s), the carrier mobility of the edge-crosslinked hydrogel structure is 10. -4 -10 -3 cm² / (V·s).

[0012] Furthermore, the upper electrode and the lower electrode are each independently a disk-shaped planar electrode, and the power-generating active material is filled between the upper electrode and the lower electrode;

[0013] And / or, the diameter of the lower electrode is 4 mm-10 mm, which is the diameter of the moisture-generating device;

[0014] And / or, the diameter of the upper electrode is 3 mm-9 mm;

[0015] And / or, the diameter of the lower electrode is 1 mm to 3 mm larger than the diameter of the upper electrode;

[0016] And / or, the diameter ratio of the upper electrode to the lower electrode is 75%-85%;

[0017] And / or, the diameter of the power-generating active material is equal to the diameter of the lower electrode;

[0018] Furthermore, the sheath layer in the power-generating active material is obtained by ultraviolet light-induced polymerization and gelation of a hydrogel precursor solution.

[0019] Furthermore, it also includes a support structure located between the upper electrode and the lower electrode; one end of the support structure is connected to the upper electrode, and the other end is connected to the lower electrode; for supporting the upper electrode and the lower electrode;

[0020] And / or, the height of the support structure limits the distance between the first electrode and the second electrode to 0.5 mm-2 mm.

[0021] Furthermore, the supporting structure is made of an insulating polymer material;

[0022] And / or, the support structure is cylindrical; with a diameter of 1 mm-2 mm.

[0023] Furthermore, the upper electrode and the lower electrode are each an independent metal electrode, forming an asymmetric electrode pair; the metal electrodes are made of Pt, Au, Ag, Cu, or Al.

[0024] Furthermore, the hydrogel precursor solution includes one or more of polymers, small molecules, and solvents;

[0025] The content of polymers in the hydrogel precursor solution is 1 wt%-5 wt%;

[0026] The solvent content in the hydrogel precursor solution is ≥40 wt%;

[0027] The hydrogel precursor solution contains a component with an acid dissociation constant < 6.5; the content of the component with an acid dissociation constant < 6.5 accounts for ≥ 40% of the solid content.

[0028] Furthermore, the polymer includes polyacrylic acid, polymethacrylic acid, polyaspartic acid, etc.; the monomer includes acrylic acid, N-fluorenylmethoxycarbonyl-phenylalanine, phytic acid, dodecylbenzenesulfonic acid, hyaluronic acid, alginate, etc.; the solvent includes water, glycerol, ethylene glycol, etc. The solvent contains at least water.

[0029] Furthermore, the hydrogel precursor solution also includes a photoinitiator. The photoinitiator is used to drive UV-induced polymerization / gelation; the photoinitiator is selected from diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, 2-hydroxy-2-methylphenylacetone, lithium phenyl-2,4,6-trimethylbenzoylphosphonate, etc.

[0030] Furthermore, the photoinitiation wavelength is 250 nm-400 nm;

[0031] And / or, the photoinitiator accounts for 0.03%-2% of the solid content of the ion-conducting aqueous solution.

[0032] And / or, the light-induced radiative flux is 0.05 J / cm². 2 -5 J / cm 2 The preferred value is 0.2 J / cm. 2 The time is 2s-100s, preferably 2s-10s; if the time is too long, the degree of cross-linking will be too high and will not meet the requirements.

[0033] A second objective of this invention is to provide a method for preparing the aforementioned moisture-generating device, characterized by comprising the following steps:

[0034] S1. An upper electrode, a lower electrode, and a support structure located between the two electrodes are disposed on a flexible substrate;

[0035] S2. Prepare hydrogel precursor solution;

[0036] S3. Fill the gap between the upper and lower electrodes, which are constrained by the support structure obtained in step S1, with the hydrogel precursor solution obtained in step S2.

[0037] S4. Light is irradiated from above the upper electrode. The precursor solution in the region below the second electrode is shielded by the second electrode and does not receive ultraviolet light irradiation, thereby forming a power-generating active material with a core-sheath structure, thus obtaining a moisture power generation device.

[0038] A third objective of this invention is to provide the application of the aforementioned moisture-generating device in humidity detection.

[0039] A fourth objective of this invention is to provide the application of the aforementioned moisture-generating device in self-powered electronic devices.

[0040] Through the above design, the hydrogel precursor solution is sandwiched between a pair of electrodes. Upon ultraviolet irradiation, the edge region solidifies to form a hydrogel sheath, while the central region remains in solution state due to the upper electrode blocking light. The resulting core-sheath structure active material exhibits ionic conductivity and water absorption capacity comparable to the precursor solution. This structure maintains the high ionic conductivity and high water storage capacity of the precursor solution while preserving device integrity through the hydrogel sheath. Furthermore, it creates a non-uniform water retention and transport rate, facilitating the establishment of a water concentration gradient and promoting the directional migration of ion carriers, thereby improving the power generation performance of wet gas power generation. The sheath and core layers exhibit significant differences in charge storage capacity, thus affecting the device's open-circuit voltage and short-circuit current. The precursor solution in the core has low viscosity, high water content, and stronger ionization capability, resulting in a higher charge storage capacity than the sheath. Therefore, a higher core layer volume fraction contributes more to the double layer, thus exhibiting a higher open-circuit voltage. Compared to the gelled sheath, the hydrogel precursor solution of the core layer has a significantly weaker ability to maintain the ion concentration gradient and directional carrier migration due to its lower viscosity; however, also due to its low viscosity, the ionic conductivity of the core layer is much higher than that of the sheath. This competition between the two factors leads to a non-linear dependence of the short-circuit current on the sheath volume fraction: when the sheath volume fraction is high, the overall ionic conductivity of the active layer is low, resulting in a smaller short-circuit current; when the sheath volume fraction is low, the ion concentration gradient in the active layer is difficult to maintain, also causing a decrease in short-circuit current. Therefore, it is necessary to maintain the diameter ratio of the upper electrode to the lower electrode at 75%-85% to provide optimal power output (open-circuit voltage and short-circuit current).

[0041] The technical solution of the present invention has the following advantages compared with the prior art:

[0042] This invention provides a moisture-generating device, its preparation method, and its application. By combining asymmetric metal electrode pairs of different sizes under UV-induced polymerization / gelation, this invention successfully realizes a method for preparing a moisture-generating device based on a power-generating active material. The power-generating active material in this invention has a core-sheath structure, which can significantly improve the power performance of the hydrogel-based moisture-generating device. Furthermore, this device structure design enables the moisture-generating device to possess a compact size, good flexibility, and excellent power generation performance. It can be used as a self-powered sensing unit for environmental humidity and human respiration monitoring sensors, achieving integrated sensing and power supply functions; or it can be used solely as a power supply component, integrated with other sensing components, and applied in a self-powered sensing unit. Attached Figure Description

[0043] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein:

[0044] Figure 1This is a schematic diagram of the structure of the moisture-generating device in this invention;

[0045] Figure 2 This is a geometric structure and dimension diagram of the moisture-generating device in this invention;

[0046] Figure 3 This refers to the mass change of the hydrogel precursor solution during ultraviolet irradiation in this invention.

[0047] Figure 4 This is a comparison of the Bode impedance spectra of the moisture-generating device exposed to ultraviolet light and the device not exposed to ultraviolet light in this invention;

[0048] Figure 5 These are SEM images of the sheath (A) and core (B) of the freeze-dried power-generating active material in this invention;

[0049] Figure 6 This is a comparison of the water absorption behavior of Example 1 and the comparative example measured under conditions of 55% relative humidity and 25°C in this invention;

[0050] Figure 7 These are the open-circuit voltage measurement results of the wet gas power generation devices assembled using different electrode pairs in this invention;

[0051] Figure 8 This is a comparison of the open-circuit voltage values ​​of the wet gas power generation devices assembled with different electrode pairs in this invention.

[0052] Figure 9 It is the short-circuit current of the wet gas power generation device with Cu / Pt as the electrode pair in this invention;

[0053] Figure 10 This invention describes the cyclic charging and discharging behavior of a wet gas power generation device obtained by periodically switching open-circuit voltage and short-circuit current measurement modes.

[0054] Figure 11 This is the open-circuit voltage of the wet gas power generation device assembled with Cu / Pt electrode pairs of different diameters in this invention, tested under conditions of 55% relative humidity and 25°C.

[0055] Figure 12 This is the short-circuit current of the wet gas power generation device assembled with Cu / Pt electrode pairs of different diameters in this invention, tested under conditions of 55% relative humidity and 25°C.

[0056] Figure 13 This invention relates to the influence of Cu / Pt electrode diameter and ambient humidity on the power generation performance of the wet gas power generation device.

[0057] Figure 14 The results are the open-circuit voltage of the moisture generator obtained in Example 1 of this invention, tested at 25°C and under different relative humidity conditions.

[0058] Figure 15 The results are the short-circuit current of the wet gas power generation device obtained in Example 1 of this invention under conditions of 25°C and different relative humidity.

[0059] Figure 16 This invention relates to the influence of Cu / Pt electrode diameter and ambient humidity on the power generation performance of the wet gas power generation device.

[0060] Figure 17 This illustrates the humidity monitoring effect of the moisture-generating device in this invention; the illustration shows the relative humidity result simultaneously measured by a hygrometer.

[0061] Figure 18 This invention relates to the monitoring of respiration by a moisture-generating device; the illustration shows a schematic diagram of the test circuit, the device assembly method using double-sided tape for fixation, and its attachment position in the philtrum area;

[0062] Figure 19 This invention relates to the monitoring of hand gestures by a moisture-generating device; the illustration shows a schematic diagram of the test circuit, the structure of the device and the piezoresistive strain gauge assembled with double-sided tape, and its attachment position at the knuckle. Detailed Implementation

[0063] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0064] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the materials and reagents used are commercially available.

[0065] CAS No. for polyvinyl alcohol: 9002-89-5; CAS No. for acrylic acid: 79-10-7; CAS No. for phytic acid: 83-86-3; CAS No. for 2,4,6-trimethylbenzoyl diphenylphosphine oxide: 75980-60-8.

[0066] Example 1

[0067] This embodiment provides a method for preparing a moisture-generating device, the specific steps of which are as follows:

[0068] (1) Using a polyimide film (125 μm thick) as the substrate, a thin copper sheet (20 μm thick) with a diameter of 5 mm is used as the lower electrode, and a thin platinum sheet (10 μm thick, surface resistance of Pt electrode <50 Ω) with a diameter of 4 mm is used as the upper electrode, and a polymethyl methacrylate support structure (500 μm high) is set.

[0069] (2) Preparation of hydrogel precursor solution: 0.2 g polyvinyl alcohol was added to a mixture of 1.8 g deionized water and 2.2 g glycerol (99%), and stirred at 90 °C for 1 hour until the polyvinyl alcohol was completely dissolved. Then, 1.8 g acrylic acid and 3.9 g phytic acid (50% aqueous solution) were added to the solution, and stirring was continued at room temperature for 30 minutes to obtain the precursor solution.

[0070] Adding 0.6 wt.% of 2,4,6-trimethylbenzoyldiphenylphosphine oxide to the precursor solution yields a hydrogel precursor solution.

[0071] (3) Use a microsyringe to inject 5 μL of hydrogel precursor solution into the gap region between the upper and lower electrodes obtained in step (1). Under the action of capillary action and the viscoelasticity of the polymer solution, the hydrogel precursor solution naturally forms a thin film and remains in the gap, with its edge in the shape of a convex meniscus.

[0072] (4) After injecting the hydrogel precursor solution, ultraviolet light is irradiated from above the upper electrode; the power of the ultraviolet light source is 11 mW, the wavelength is 365 nm, and the irradiation time is 2 seconds; 2 seconds of ultraviolet exposure is sufficient for the hydrogel precursor solution at the edge to form a gel structure. The hydrogel precursor solution in the area below the upper electrode is shielded by the upper electrode and does not receive ultraviolet light irradiation, so no cross-linking reaction occurs. Thus, a power-generating active material with a core-sheath structure is formed, the sheath layer at the edge is a cross-linked hydrogel structure, and the inner core layer is an uncross-linked hydrogel precursor solution; thus forming a moisture-generating device. The structural schematic diagram of the obtained moisture-generating device is shown below. Figure 1 As shown, the geometric structure and dimensions are as follows: Figure 2 As shown.

[0073] Among them, the mass change of the hydrogel precursor solution during ultraviolet irradiation is as follows: Figure 3 As shown, the system weight loss during this rapid irradiation process is less than 1%.

[0074] Comparative Example 1

[0075] This comparative example provides a method for preparing a wet power generation device, which is similar to Example 1, except that the hydrogel precursor solution in step (4) is not irradiated with ultraviolet light.

[0076] Comparative Example 2

[0077] This comparative example provides a method for fabricating a device, which is similar to Example 1, except that: no upper electrode is set in step (1); and the hydrogel precursor solution is not irradiated with ultraviolet light in step (4).

[0078] Impedance spectra of the hydrogel precursor solution and the cross-linked gel sample were measured using an impedance analyzer to analyze their ionic conductivity behavior. Figure 4 As shown, 2 seconds of UV irradiation only caused a slight increase in the ionic resistance of the device. Due to the blocking of UV light by the top Pt electrode, the polymerization / gelation reaction of the hydrogel precursor solution only occurred in the edge region of the device, while the central region remained unpolymerized. Therefore, the ionic conductivity was not significantly affected by the decrease in carrier mobility caused by gelation.

[0079] The power-generating active material obtained in Example 1 was freeze-dried and then observed using a scanning electron microscope (SEM). Figure 5 As shown, the edge-crosslinked hydrogel structure (sheath) exhibits a porous structure, while the hydrogel precursor (core) displays a more uniform morphology. This is because, in the UV-irradiated edge region, acrylic acid polymerizes into polyacrylic acid, which forms an interpenetrating network with polyacrylamide, ultimately constructing a physically crosslinked three-dimensional gel structure. This gel network undergoes phase separation during freeze-drying, resulting in a porous structure. In contrast, no polyacrylic acid is generated in the central region of the device; therefore, even after freeze-drying, the originally uniform hydrogel precursor solution retains its homogeneous morphology. This result verifies its core-sheath structure and non-uniform gelation characteristics.

[0080] To monitor changes in sample mass, the water absorption performance of the device was measured using an electronic balance under conditions of 55 ± 5% relative humidity and 25 ± 2℃. For example... Figure 6 As shown, the water absorption kinetics of the power generation device with a core-sheath structure (Example 1) and the device without ultraviolet irradiation (Comparative Example 1) are almost identical. This phenomenon can be attributed to the fact that the volume fraction of the gel sheath layer in the active layer of the core-sheath structure is much smaller than the volume fraction of the precursor solution in the central region. Furthermore, the mass of both devices increases with increasing test time, indicating that the hydrogel precursor solution in the device continuously absorbs moisture from the environment under the test conditions (55% relative humidity, 25°C), regardless of whether it has been exposed to ultraviolet irradiation. This is because capillary action and its confinement effect play a crucial role in preventing moisture evaporation in the narrow gaps of the humidification power generation device, coupled with the excellent water absorption of the hydrogel precursor solution, resulting in the device's ability to continuously absorb water from the environment without reaching saturation.

[0081] The mass change of the control group device (Comparative Example 2) with the upper electrode removed was further measured under the same conditions. In this case, the upper surface of the solution in the device was completely exposed to the environment, and the gap confinement effect was greatly reduced. Figure 6 As shown, the mass of the topless electrode device gradually decreases with the test time, which confirms that the capillary action and confinement effect of the device play an important role in maintaining the water absorption capacity of the active layer of its core-sheath structure.

[0082] Example 2

[0083] This embodiment provides a method for preparing a moisture-generating device, which is similar to that of Embodiment 1, except that the lower electrode is a Pt electrode and the upper electrode is Ag.

[0084] Example 3

[0085] This embodiment provides a method for preparing a moisture-generating device, which is similar to that of Embodiment 1, except that the lower electrode is a Cu electrode and the upper electrode is Ag.

[0086] Comparative Example 3

[0087] This comparative example provides a method for preparing a moisture-generating device, which is similar to Example 1, except that the lower electrode is a Cu electrode and the upper electrode is Cu.

[0088] The open-circuit voltage and short-circuit current of the aforementioned moisture-generating devices (electrode pair combinations of Cu / Pt, Pt / Ag, Cu / Ag, and Cu / Cu) were measured using a digital multimeter. During the testing, the devices were placed in a temperature and humidity chamber with a relative humidity of 55% and a temperature of 25°C to evaluate their open-circuit voltage. The results are as follows: Figure 7 As shown, the devices in the embodiments can all output stable open-circuit voltages, the specific values ​​of which are summarized in [the table below]. Figure 8 Comparative Example 3 (Cu / Cu electrode) was 0 ± 0.3 mV, Example 3 (Cu / Ag electrode) was 177 ± 0.8 mV, Example 2 (Ag / Pt electrode) was 468 ± 2 mV, and Example 1 (Cu / Pt electrode) was 602 ± 4 mV.

[0089] The short-circuit current of the moisture-generating device obtained in Example 1 was evaluated at 55% relative humidity and 25°C. The results are as follows: Figure 9 As shown in the diagram, the short-circuit current gradually decreases from an initial high value of approximately 50 μA, eventually stabilizing at approximately 9 μA, corresponding to a volumetric current density of approximately 900 μA / cm³. Periodic (approximately 20-hour cycle) measurement mode switching (from open-circuit voltage to short-circuit current) was performed on this device (Cu / Pt electrode, 55% relative humidity, 25℃). The circuit diagram is shown below. Figure 10 As shown. From Figure 10 As can be seen, when the device is short-circuited (switching from open-circuit voltage to short-circuit current), its voltage and current outputs decrease simultaneously; while when switching back from short-circuit current to open-circuit voltage mode, the voltage and current gradually recover to their original levels, and this process can be repeated cyclically. During the discharge process (switching from open-circuit voltage to short-circuit current mode), the charge stored in the ion-conductive hydrogel active layer is released, generating a transient discharge current and causing a voltage drop; while during the charging process (switching back from short-circuit current to open-circuit voltage mode), the reverse process occurs, generating a transient charging current and causing the voltage to rise.

[0090] Example 4

[0091] This embodiment provides a method for preparing a moisture-generating device, which is similar to that of Embodiment 1, except that the diameter of the lower electrode is 4 mm and the diameter of the upper electrode is 3 mm.

[0092] Example 5

[0093] This embodiment provides a method for preparing a moisture-generating device, which is similar to that of Embodiment 1, except that the diameter of the lower electrode is 6 mm and the diameter of the upper electrode is 5 mm.

[0094] Comparative Example 4

[0095] This comparative example provides a method for preparing a moisture-generating device, which is similar to Example 1, except that the diameter of the lower electrode is 3 mm and the diameter of the upper electrode is 2 mm.

[0096] By fixing the width of the annular region irradiated by ultraviolet light at 0.5 mm, the volume fraction of the gel sheath layer in the active layer of the device can be adjusted by changing the diameters of the upper and lower electrodes. The larger the diameters of the upper and lower electrodes, the lower the volume fraction of the gel sheath layer (hydrogel) and the higher the volume fraction of the core layer (precursor solution). Figure 11 and Figure 12 The open-circuit voltage and short-circuit current results of the moisture-generating devices obtained in Examples 1, 4-5, and Comparative Example 4 are shown respectively under conditions of 55% relative humidity and 25°C. Figure 13 The relationship between the Cu electrode diameter and the open-circuit voltage and short-circuit current output was summarized. It can be seen that the open-circuit voltage gradually increases with increasing Cu electrode diameter (i.e., decreasing gel sheath volume fraction). Furthermore, there exists a ratio of the upper electrode diameter to the lower electrode diameter that maximizes the short-circuit current, yielding the optimal gel sheath volume fraction.

[0097] The open-circuit voltage and short-circuit current of the moisture generator obtained in Example 1 at different ambient humidity levels at room temperature were tested. Figure 14 and 15 ). Figure 16 The relationship between stable open-circuit voltage and short-circuit current output and relative humidity is shown. It can be seen that within the tested humidity range (40%–70% RH), the short-circuit current of the device increases linearly with relative humidity; while the open-circuit voltage remains stable at low relative humidity (<60% RH), but decreases with increasing humidity at high relative humidity (>60% RH).

[0098] In addition, when the gap between the upper and lower electrodes is too large, the liquid cannot be effectively confined within the gap through capillary action, resulting in the loss of the gap confinement effect. At the same time, due to the lack of sufficient surface tension and wetting effect, the liquid is also unable to form a stable meniscus structure, thus affecting the overall performance and response behavior of the device.

[0099] In active materials with core-sheath structures: if the sheath layer is too thick, the viscosity of its hydrogel system will be high, which will significantly limit the kinetic process of the material absorbing moisture from the ambient air and reduce the moisture absorption response rate; if the sheath layer is too thin, it will be difficult to effectively maintain the overall morphological stability of the core-sheath structure, and at the same time, it will be impossible to establish a sufficient humidity gradient inside the material, thereby weakening its power generation performance.

[0100] Application Example 1

[0101] The device exhibits a linear relationship between its short-circuit current and ambient relative humidity, making it suitable for use as a self-powered humidity sensor. A single device was placed in a laboratory environment, and humidity changes were continuously monitored over 120 hours. Figure 17 As shown, the fluctuations in relative humidity values ​​recorded by commercial hygrometers closely match the changes in short-circuit current output by the device prepared in this invention.

[0102] Application Example 2

[0103] The moisture-generating device of this invention exhibits excellent moisture response characteristics. Combined with its compact structure (height × diameter = 1 mm × 5 mm) and good flexibility, it is ideally suited as a self-powered wearable respiratory sensor for monitoring human respiratory status. Figure 18 As shown, the device is attached to the philtrum area using medical double-sided tape, and its short-circuit current is continuously monitored to record moisture fluctuations caused by exhalation and inhalation, providing a convenient way to monitor the subject's respiratory status. The device's short-circuit current signal changes periodically with respiratory movements: during inhalation, the decrease in local humidity leads to a decrease in the short-circuit current, while during exhalation, the increase in local humidity causes an increase in the short-circuit current. Therefore, respiratory rate and depth can be directly reflected by the periodic changes in the device's short-circuit current.

[0104] Application Example 3

[0105] A moisture-generating device is connected in series with a commercially available metal piezoresistive element to construct a self-powered wearable strain sensor. When the piezoresistive element undergoes mechanical deformation, its resistance changes, which in turn causes a change in the current of the generating device, thus achieving the required self-powered mechanical strain sensing function. It is secured to the index finger with double-sided tape for gesture monitoring demonstration. Figure 19As shown, it can be attached to the finger for gesture monitoring. Experiments show that when the finger repeatedly bends, holds, and returns to its original position at different speeds, the device's current output can respond well to these movements in sync, exhibiting high repeatability and low hysteresis.

[0106] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A wet-gas power generator characterized by comprising: The humidity generator comprises a flexible substrate, an upper electrode, a lower electrode and a power generation active material; the power generation active material is arranged between the upper electrode and the lower electrode; The power generation active material has a core-sheath structure, the sheath layer of the edge is a cross-linked hydrogel structure, and the core layer is a hydrogel precursor solution; The sheath layer limits the shape of the hydrogel precursor solution in the core layer and contacts the atmosphere; The diameter of the lower electrode is 4 mm-10 mm; The diameter of the upper electrode is 3 mm-9 mm; The diameter ratio of the upper electrode to the lower electrode is 75%-85%.

2. The moisture power generator according to claim 1, wherein The upper electrode and the lower electrode are each independently a planar electrode in the shape of a disc; And / or, the diameter of the lower electrode is 1 mm-3 mm larger than the diameter of the upper electrode; And / or, the diameter of the power generation active material is equal to the diameter of the lower electrode.

3. The moisture power generator according to claim 1, wherein The sheath layer is obtained by ultraviolet light-induced polymerization and gelation of the hydrogel precursor solution.

4. The moisture power generator according to claim 1, wherein A support structure is further included between the upper electrode and the lower electrode; one end of the support structure is connected to the upper electrode, and the other end is connected to the lower electrode; And / or, the height of the support structure is 0.5 mm-2 mm.

5. The moisture power generator according to claim 1, wherein The upper electrode and the lower electrode are each independently an asymmetric metal electrode; the material of the metal electrode is Pt, Au, Ag, Cu or Al.

6. The wet gas power generator according to claim 1 or 3, wherein The hydrogel precursor solution comprises one or more of a polymer, a small molecule and a solvent; The content of the polymer in the hydrogel precursor solution is 1 wt%-5 wt%; The content of the solvent in the hydrogel precursor solution is ≥40 wt%; The hydrogel precursor solution contains a component with an acid dissociation constant <6.5; the content of the component with the acid dissociation constant <6.5 accounts for ≥40% of the solid content.

7. The moisture power generator according to claim 1, wherein The hydrogel precursor solution further comprises a photoinitiator.

8. The method of producing a wet-type power generating device according to any one of claims 1 to 7, characterized by, The method comprises the following steps: S1, arranging an upper electrode, a lower electrode and a support structure between the two electrodes on a flexible substrate; S2, preparing a hydrogel precursor solution; S3, filling the hydrogel precursor solution obtained in step S2 into the gap between the upper electrode and the lower electrode limited by the support structure obtained in step S1; S4, performing light irradiation from above the upper electrode to form a power generation active material with a core-sheath structure, thereby obtaining a humidity generator.

9. Application of the humidity generator of any one of claims 1-7 in humidity detection.

10. Application of the humidity generator of any one of claims 1-7 in self-powered electronic devices.

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