A synergistically regulated evaporation-driven power generation hydrogel, its preparation method and application

Abstract

This invention belongs to the field of energy materials and water evaporation power generation technology, specifically disclosing a synergistically regulated evaporation-driven power generation hydrogel, its preparation method, and its application. The hydrogel comprises a polymer matrix and alkali metal ions dispersed in the polymer matrix; the polymer matrix is ​​a polyacrylamide hydrogel or a polyvinyl alcohol hydrogel, and the alkali metal ions are Li... + Na + or K + One or more of the above, including reduced graphene oxide dispersed in a polymer matrix. This invention employs the above-mentioned synergistically regulated evaporation-driven power generation hydrogel, its preparation method, and its application. Based on ion-specific effects and photothermal synergistic regulation, it enhances power generation performance, maintains stable performance ranking in simulated seawater / sewage, and possesses strong environmental adaptability.

Description

Technical Field

[0001] This invention relates to the field of energy materials and water evaporation power generation technology, and in particular to a synergistically regulated evaporation-driven power generation hydrogel, its preparation method, and its application. Background Technology

[0002] The depletion of resources and environmental pollution caused by traditional fossil fuels have made the research of efficient conversion technologies for low-grade environmental energy a hot topic in the energy field. Water evaporation occurs in daily life, and this phase transition process contains abundant energy. Evaporation-driven power generation devices, with their advantages of simple equipment and environmental friendliness, provide a feasible approach to energy development during water evaporation. Among many materials (carbon-based materials, semiconductor materials, polymer materials), hydrogel materials have unique advantages; their three-dimensional hydrophilic network provides an ideal environment for ion transport and energy conversion. However, existing technologies suffer from unclear ion regulation mechanisms, unknown synergistic effects of functional fillers, and poor adaptability to complex environments, limiting their application. Summary of the Invention

[0003] The purpose of this invention is to provide a synergistically regulated evaporation-driven power generation hydrogel, its preparation method, and its application. Based on the ion-specific effect and photothermal synergistic regulation, it enhances power generation performance, maintains stable performance ranking in simulated seawater / sewage, and has strong environmental adaptability.

[0004] To achieve the above objectives, the present invention provides a synergistically regulated evaporation-driven power generation hydrogel, comprising a polymer matrix and alkali metal ions dispersed in the polymer matrix; the polymer matrix is ​​a polyacrylamide hydrogel or a polyvinyl alcohol hydrogel, and the alkali metal ions are Li... + Na + or K + One or more of them.

[0005] Preferably, it also includes reduced graphene oxide dispersed in a polymer matrix.

[0006] This invention also provides a method for preparing a synergistically regulated evaporation-driven power generation hydrogel, which uses free radical polymerization to prepare a chemically cross-linked alkali metal ion composite polyacrylamide hydrogel, comprising the following steps: S1. Preparation of hydroxypropyl cellulose solution (HPC solution): By weight, add 0.8 to 1 part of hydroxypropyl cellulose powder to 80 to 100 parts of deionized water preheated to 60°C, mechanically stir for 15 minutes to fully disperse it, and then continue stirring at room temperature for 6 hours to ensure complete dissolution. S2. Preparation of the hydrogel precursor solution: Dissolve 1-2 parts by weight of acrylamide, 0.01-0.02 parts by weight of N,N'-methylenebisacrylamide, and 0.02-0.03 parts by weight of initiator in deionized water, then add a certain volume of alkali metal ion solution and 1 mL of the hydroxypropyl cellulose solution obtained in S1; wherein the alkali metal ion solution is one or more of LiCl, NaCl, or KCl solution, and the concentration of LiCl, NaCl, or KCl solution is 0.01-0.02 mol·L⁻¹. -1 ; S3. By weight, add 0.001~0.002 parts of N,N,N',N'-tetramethylethylenediamine to the hydrogel precursor solution obtained in S2 to initiate a polymerization reaction and obtain an alkali metal ion composite polyacrylamide hydrogel.

[0007] Preferably, before S3, the method further includes adding 0.02 to 0.04 parts by weight of reduced graphene oxide to the hydrogel precursor solution obtained in S2.

[0008] Preferably, the initiator includes ammonium persulfate or potassium persulfate.

[0009] This invention also provides a method for preparing a synergistically regulated evaporation-driven power generation hydrogel, which uses a cyclic freeze-thaw method to prepare a physically cross-linked alkali metal ion composite polyvinyl alcohol hydrogel, comprising the following steps: Step 1: Prepare polyvinyl alcohol (PVA) solution: By weight, slowly add 10-12 parts of PVA powder to 80-100 parts of alkali metal ion solution, stir gently to disperse and wet it evenly, let it stand for more than 30 minutes to allow it to swell fully, and then place it in an oil bath at 90-100℃ and stir continuously at 600 rpm for 4 hours to ensure complete dissolution. Step 2: After the polyvinyl alcohol solution prepared in Step 1 has been left to stand for 12 hours, it is poured into the mold. Then, the mold containing the PVA solution is placed in a low temperature freezer at -15~-30℃ and frozen for 12 hours. The completely frozen sample is then transferred to room temperature and thawed for 4 hours until the frozen sample is completely melted into an elastic gel, thus obtaining an alkali metal ion composite polyvinyl alcohol hydrogel.

[0010] This invention also provides an application of a synergistically regulated evaporation-driven hydrogel in generating electricity under infrared or natural light irradiation.

[0011] Preferably, under infrared light irradiation, a hydration radius of 0.36 nm and an ion mobility range of (5.0~5.5)×10⁻⁶ are used. -8 m 2 ·V -1 ·s -1 , containing Na +The aforementioned evaporation-driven power-generating hydrogel generates electricity through infrared light-induced instantaneous evaporation, the establishment of an ion concentration gradient, and network relaxation efficiency, with an infrared light intensity range of 500~1000 W·m. -2 The evaporation rate of the hydrogel surface is 1.5~2.5; Alternatively, preferably, under natural light irradiation, a hydration radius of 0.33 nm and an ion mobility range of (7.4~7.8)×10⁻⁶ are used. -8 m 2 ·V -1 ·s -1 Contains K + The aforementioned evaporation-driven power-generating hydrogel generates electricity through continuous evaporation under natural light, the establishment of an ion concentration gradient, and network relaxation efficiency, with a natural light intensity range of 100~300 W·m. -2 The evaporation rate of the hydrogel surface is 0.3~0.8 kg·m. -2 ·h -1 .

[0012] Preferably, a hydration radius of 0.38 nm and an ion mobility range of (3.8~4.2)×10⁻⁶ are used. -8 m 2 ·V -1 ·s -1 Li + The evaporation-driven power-generating hydrogel described herein generates electricity through a concentration threshold effect.

[0013] Preferably, the evaporation-driven power-generating hydrogel uses alkali metal ions and reduced graphene oxide, with the alkali metal ion molar number being higher than 0.003 mol·L⁻¹. -1 It generates electricity through the photothermal enhancement effect of reduced graphene oxide.

[0014] Therefore, the present invention employs the above-mentioned synergistically regulated evaporation-driven power generation hydrogel, its preparation method, and its application, with the following beneficial effects: This invention clarifies the ion-specific regulation mechanism: the hydration radius, ion mobility, and interaction strength of alkali metal ions with the hydrogel network jointly determine the carrier migration rate and power generation performance; the ion concentration regulates the network crosslinking density, forming an electrical performance threshold effect. This mechanism holds true in both chemically crosslinked (polyacrylamide, AH) and physically crosslinked (polyvinyl alcohol, PVA) hydrogel systems. AH hydrogels exhibit high crosslinking density and strong structural rigidity, providing a high initial carrier concentration even at low concentrations, resulting in a higher overall initial current. PVA hydrogels utilize dynamic hydrogen bonding crosslinking, resulting in greater network flexibility, smoother current decay time fluctuations, and a more moderate decay rate increase, allowing for the selection of suitable substrates based on different application scenarios.

[0015] This invention establishes a correlation between light-evaporation-current response, forming a performance optimization scheme for ion-light matching: achieving differentiated control of power generation dynamics by light mode, with infrared light (500~1000 W·m) -2 The process is dominated by "instantaneous high-intensity evaporation," with an evaporation rate of 1.5~2.5 kg·m³. -2 ·h -1 Fast current response; natural light (100~300W·m) -2 The following is characterized by "continuous weak evaporation", with an evaporation rate of 0.3~0.8 kg·m³. -2 ·h -1 The output is more stable. Furthermore, under infrared light irradiation, Na-containing... + The system exhibits the best initial current (average 1.268 mA), significantly higher than other systems; under natural light irradiation, it contains K... + The system exhibits superior overall power generation performance due to its high mobility; Li-containing + The system exhibits a unique concentration threshold effect, with a jump in current when the network porous-dense structure is reversed.

[0016] This invention achieves dual enhancement of photothermal and electrical conductivity through modified reduced graphene oxide (rGO): introducing rGO as a functional filler simultaneously provides enhanced photothermal conversion and auxiliary conductivity, significantly improving the initial current of the device. This is particularly relevant in the high ion concentration range (>0.003 mol·L⁻¹). -1 The photothermal gain effect dominates, significantly improving the initial current of the device; in the low ion concentration range (<0.002 mol·L⁻¹), the initial current of the device is significantly increased. -1 rGO aggregates can easily interfere with the hydrogel network structure, resulting in lower initial current in some systems than in the unmodified system, providing a quantitative basis for the rational addition of functional fillers.

[0017] This invention exhibits excellent adaptability to complex aquatic environments: the device demonstrates stable power generation performance in pure water, simulated seawater, and simulated wastewater. Organic impurities and competition with multiple ions only cause changes in the overall current amplitude without disrupting the ion-specific regulation. Among them, the medium-concentration LiCl system (AH-LiCl-3) maintains optimal initial current and evaporation rate in complex aquatic environments due to the "porous-dense structure reversal," and can be directly applied to synergistic scenarios of seawater desalination, wastewater treatment, and low-grade environmental energy capture.

[0018] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0019] Figure 1This is a comparison of current-time curves of the device in Embodiment 1 of the present invention under different alkali metal ions and light irradiation, where a is the LiCl system under infrared light irradiation, b is the NaCl system under infrared light irradiation, c is the KCl system under infrared light irradiation, d is the LiCl system under natural light irradiation, e is the NaCl system under natural light irradiation, and f is the KCl system under natural light irradiation. Figure 2 This is a comparison diagram of the initial current of the device in Embodiment 1 of the present invention under different alkali metal ions and light irradiation, where a is infrared light irradiation and b is natural light irradiation; Figure 3 The device of Embodiment 1 of the present invention exhibits current decay characteristics under infrared / natural light, where a is the current decay amount under infrared light irradiation, b is the current decay amount under natural light irradiation, c is the current decay time under infrared light irradiation, and d is the current decay time under natural light irradiation. Figure 4 These are the initial currents of the device in different ion systems according to Embodiment 2 of the present invention, where a is the initial current under infrared light irradiation, b is the initial current under natural light irradiation, c is a comparison of the initial currents of PVA and AH under infrared light irradiation, and d is a comparison of the initial currents of PVA and AH under natural light irradiation. Figure 5 These are the initial current enhancement effect diagrams of the device in different ion systems according to Embodiment 2 of the present invention, where a is the initial current under infrared light irradiation, b is the initial current under natural light irradiation, c is the comparison of the initial current of rGO under infrared light irradiation, and d is the comparison of the initial current of rGO under natural light irradiation. Figure 6 This is a comparison chart of the power generation performance of the power generation device of Embodiment 1 of the present invention in simulated seawater / sewage, where a is the initial current of each system in simulated seawater, b is the evaporation rate of each system in simulated seawater, c is the initial current of each system in simulated sewage, and d is the evaporation rate of each system in simulated sewage. Detailed Implementation

[0020] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0022] Example 1 A synergistically regulated evaporation-driven power generation hydrogel, specifically a polyacrylamide (AH) hydrogel-based power generation device, was prepared by preparing polyacrylamide hydrogels containing different types and concentrations of alkali metal ions, and testing their initial current and current decay characteristics under infrared light and natural light.

[0023] 1. Device fabrication: Preparation of hydroxypropyl cellulose (HPC) solution: Add 0.9g of hydroxypropyl cellulose powder to 90mL of deionized water preheated to 60℃, stir mechanically for 15min to fully disperse it, and then continue stirring at room temperature for 6h to obtain a uniform and transparent HPC solution.

[0024] Precursor solution preparation: Dissolve 1.5 g acrylamide, 0.015 g N,N'-methylenebisacrylamide, and 0.025 g ammonium persulfate initiator in 80 mL of deionized water. Add 1 mL, 2 mL, 3 mL, 4 mL, and 5 mL of 0.01 mol·L⁻¹ solution to the mixture, respectively. -1 LiCl, NaCl, or KCl solutions (corresponding to ion molar numbers of 1×10⁻⁶) -5 mol, 2×10 -5 mol, 3×10 -5 mol, 4×10 -5 mol, 5×10 -5 Add 1 mL of the prepared HPC solution (mol), and stir until homogeneous.

[0025] Polymerization reaction: 0.0015 g of N,N,N',N'-tetramethylethylenediamine (TEMED) was added to the above precursor solution. After rapid stirring, the mixture was poured into a 2 cm × 2 cm × 0.5 cm mold and allowed to stand at room temperature for 2 h to complete the polymerization, resulting in polyacrylamide hydrogel-based power generation devices, which were labeled as AH-LiCl-n, AH-NaCl-n, and AH-KCl-n (n=1-5), respectively.

[0026] 2. Alkali metal ions Li + Na + K + The intrinsic parameters range as follows: their hydration radii are 0.38 nm, 0.36 nm, and 0.33 nm, respectively, and their ion mobilities range from (3.8 to 4.2) × 10⁻⁶. -8 m 2 ·V -1 ·s -1 (5.0~5.5)×10 -8 m 2 ·V -1 ·s -1 and (7.4~7.8)×10 -8 m 2 ·V -1 ·s -1 The infrared light intensity range is 500~1000 W·m. -2 The evaporation rate of the hydrogel surface can reach 1.5~2.5 kg·m. -2 ·h -1Natural light intensity ranges from 100 to 300 W·m. -2 The evaporation rate is approximately 0.3~0.8 kg·m³. -2 ·h -1 .

[0027] 3. Performance Testing: Illumination conditions: Infrared light intensity 800 W·m -2 Natural light intensity 200 W·m -2 ; Test parameters: Record the current change of the device within 0-600s, and extract the initial current (current value at t=0s), current decay (the difference between the initial current and the current at 600s), and decay time (the time required for the current to decay to 50% of the initial value).

[0028] 4. Experimental Results and Analysis: 4.1 Current-time curves of polyacrylamide hydrogel-based evaporation-driven power generation devices under different alkali metal ions and light irradiation are shown below. Figure 1 As shown; the initial current comparison results are as follows Figure 2 As shown: Under infrared light irradiation, the average initial current of the AH-NaCl system reached 1.268 mA, significantly higher than that of the AH-LiCl system (1.069 mA) and the AH-KCl system (0.972 mA). This difference stems from the presence of Na+. + The hydration radius (0.36 nm) has the best matching degree with the pore size of the polyacrylamide network, and the interaction strength between it and the network is moderate, resulting in the highest carrier migration rate.

[0029] Under natural light: the AH-KCl system exhibits the best overall power generation performance, with an average initial current of 0.892 mA, higher than the AH-NaCl (0.785 mA) and AH-LiCl (0.673 mA) systems. This is due to the slower evaporation rate under natural light (0.5 kg·m³). 2 ·h -1 ), ion mobility becomes the dominant factor, K + The ion mobility (7.4~7.8×10) -8 m 2 ·V -1 ·s -1 It is significantly higher than the other two ions.

[0030] Concentration effect: The AH-LiCl system at a molar number of ions of 3 × 10⁻⁶ -5 A current jump occurred at mol, corresponding to the inversion of the hydrogel network from a porous structure to a dense structure, verifying the Li... + The system has a unique concentration threshold effect.

[0031] 4.2 Comparison of current decay characteristics of polyacrylamide hydrogel-based evaporation-driven power generation devices under infrared / natural light is as follows: Figure 3 As shown: Under infrared light: the current decay rate of all systems is relatively fast, with the decay time concentrated between 150-250 seconds, and the decay amount is 40%-60% of the initial current. This is because of the "instantaneous strong evaporation" under infrared light (evaporation rate 2.0 kg·m³). -2 ·h -1 This leads to the rapid establishment of an ion concentration gradient, while the rapid contraction and relaxation of the hydrogel network hinders the continuous migration of ions.

[0032] Under natural light: the current decay rate slows down significantly, the decay time is extended to 300-450s, and the decay amount is only 20%-35% of the initial current. The "continuous weak evaporation" mode makes the ion concentration gradient more gradual, the network relaxation efficiency is higher, and the output is more stable.

[0033] Example 2 A synergistically regulated evaporation-driven power generation hydrogel, specifically a reduced graphene oxide (rGO) modified polyacrylamide hydrogel-based power generation device, was prepared by fabricating rGO-modified polyacrylamide hydrogels and studying the enhancing effect of functional fillers on power generation performance and their concentration thresholds.

[0034] 1. Device fabrication: PVA solution preparation: Slowly add 11g of PVA powder to 90mL of a 0.01mol·L⁻¹ solution. -1 Disperse and wet the PVA solution evenly in LiCl, NaCl, or KCl salt water, and let it stand for 30 minutes to allow it to swell fully. Then place it in a 95℃ oil bath and stir continuously at 600 rpm for 4 hours to obtain a homogeneous and transparent PVA solution. Let it stand for 12 hours to remove bubbles.

[0035] Physical cross-linking molding: PVA solution was injected into a 2cm×2cm×0.5cm mold and placed in a -20℃ low temperature freezer for 12h. After being taken out, it was thawed at room temperature for 4h to complete one freeze-thaw cycle, and polyvinyl alcohol hydrogel-based power generation devices were obtained, which were labeled as PVA-LiCl-n, PVA-NaCl-n, and PVA-KCl-n (n=1-5).

[0036] 2. Performance Testing: Illumination conditions: Infrared light intensity 800 W·m -2 Natural light intensity 200 W·m -2 ; Test parameters: Record the current change of the device within 0-600s and extract the initial current (the current value at t=0s).

[0037] 3. Experimental Results and Analysis: The initial current results of polyacrylamide hydrogel-based evaporation-driven power generation devices and polyvinyl alcohol hydrogel-based evaporation-driven power generation devices in different ionic systems are as follows: Figure 4 As shown: Overall performance differences: The initial current of PVA hydrogels is lower than that of AH hydrogels in all ionic systems. For example, the initial current of PVA-NaCl-3 under infrared light is 0.875 mA, only 66.1% of that of AH-NaCl-3 (1.324 mA). This is because AH hydrogels are covalently chemically cross-linked, with high cross-linking density and strong structural rigidity, providing a high initial carrier concentration even at low concentrations; while PVA hydrogels are physically cross-linked by hydrogen bonds, with strong network flexibility, resulting in a more significant ion binding effect at low concentrations and lower carrier release efficiency.

[0038] Verification of common patterns: The ion-specific patterns of the PVA system are highly consistent with those of the AH system: the PVA-NaCl system has the best initial current under infrared light, the PVA-KCl system has the best performance under natural light, and the PVA-LiCl system also has the best performance at 3×10⁻⁶. -5 A current threshold appears at a mol ion concentration.

[0039] Differences in decay characteristics: The current decay time of the PVA system fluctuates more smoothly, and the increase in decay amount is more moderate. For example, under infrared light, the decay amount of PVA-NaCl-5 is 38% of the initial current, lower than that of AH-NaCl-5 (56%). This is due to the self-healing ability of the dynamic hydrogen bond network of PVA, which can alleviate the hindrance of ion migration to network contraction caused by evaporation.

[0040] Example 3 A synergistically regulated evaporation-driven power generation hydrogel, specifically a polyvinyl alcohol (PVA) hydrogel-based power generation device, was prepared by preparing PVA hydrogels containing different alkali metal ions and comparing them with polyacrylamide hydrogels to verify the influence of crosslinking mode on power generation performance.

[0041] 1. Device fabrication: The difference from Example 1 is that, in the precursor solution preparation step, an additional 0.03g of reduced graphene oxide powder is added and ultrasonically dispersed for 30min to ensure uniform dispersion; The remaining steps are the same as in Example 1, and rGO modified hydrogel devices are obtained, which are labeled as AH-LiCl-n-rGO, AH-NaCl-n-rGO, and AH-KCl-n-rGO (n=1-5).

[0042] 2. Performance Testing: Illumination conditions: Infrared light intensity 800 W·m -2 Natural light intensity 200 W·m -2 ; Test parameters: Record the current change of the device within 0-600s, and extract the initial current (current value at t=0s), current decay (the difference between the initial current and the current at 600s), and decay time (the time required for the current to decay to 50% of the initial value).

[0043] 3. Experimental Results and Analysis: Results of the initial current enhancement effect of reduced graphene oxide modified polyacrylamide hydrogel-based evaporation-driven power generation device in different ionic systems are as follows: Figure 5 As shown: Photothermal enhancement: The introduction of rGO significantly improves the initial current of high ion concentration systems. For example, the initial current of AH-NaCl-5-rGO reaches 1.872 mA, which is 32.3% higher than that of unmodified AH-NaCl-5 (1.415 mA). This is because rGO has excellent photothermal conversion performance, which can increase the surface temperature of the hydrogel and accelerate the evaporation rate. At the same time, its conductive network can assist in carrier transport.

[0044] Concentration threshold effect: High ion concentration range (ion moles > 3 × 10⁻⁶) -5 mol, corresponding to a system ion concentration > 0.003 mol·L⁻¹ -1 The photothermal gain effect dominates, and the initial current of all modified systems is higher than that of the unmodified system; in the low ion concentration range (ion moles < 2 × 10⁻⁶), the initial current is higher. -5 mol, corresponding to an ion concentration of <0.002 mol·L⁻¹ in the system. -1 rGO aggregates interfere with the hydrogel network structure, leading to a decrease in the performance of some systems. For example, the initial current of AH-LiCl-1-rGO is 0.721 mA, which is lower than that of unmodified AH-LiCl-1 (0.785 mA).

[0045] Ion specificity is maintained: rGO modification does not change the ion specificity law. Under infrared light, the initial current of the AH-NaCl-n-rGO system is still optimal, which verifies the stability of the core regulation mechanism.

[0046] Test Using pure water, simulated seawater, and simulated sewage as water sources, the initial current and evaporation rate of the devices AH-LiCl-1, AH-LiCl-3, AH-NaCl-2, AH-NaCl-5, AH-KCl-1, and AH-KCl-5 in Example 1 were tested under infrared light to evaluate their power generation performance in complex aquatic environments, thus verifying their environmental adaptability.

[0047] 1. Test water source preparation: Simulated seawater: Prepare an aqueous solution containing 3.5 wt% NaCl; Simulated wastewater: 0.5wt% glucose, 0.2wt% urea, 0.1wt% MgCl2, and 0.1wt% CaCl2 were added to deionized water to simulate the organic impurities and multi-ion environment in domestic sewage.

[0048] 2. The initial current of each system in the simulated seawater is as follows: Figure 6 As shown in 'a', the evaporation rates of each system in the simulated seawater are as follows: Figure 6 As shown in b, the initial current of each system in the simulated wastewater is as follows: Figure 6 As shown in c, the evaporation rates of each system in the simulated wastewater are as follows: Figure 6 As shown in d.

[0049] Depend on Figure 6 It can be seen that in both simulated seawater and simulated wastewater, the power generation performance ranking is AH-NaCl-5 > AH-LiCl-3 > AH-KCl-5 > AH-NaCl-2 > AH-LiCl-1 > AH-KCl-1, which is completely consistent with the pure salt system. The competition between organic impurities and multiple ions only leads to a decrease in the overall current amplitude (approximately 25% decrease in simulated seawater and approximately 35% decrease in simulated wastewater), but does not disrupt the ion-specific regulation. AH-LiCl-3 still exhibits the best overall performance in complex aquatic environments, with an initial current of 0.942 mA and an evaporation rate of 1.87 kg·m³ in simulated seawater. -2 ·h -1 The performance was significantly higher than other systems. This is attributed to the "porous-dense structure inversion" at certain concentrations, which ensured both sufficient water transport channels and a high carrier concentration. The device can operate stably for more than 6 hours in complex aquatic environments without significant performance degradation, indicating that it can be directly applied to synergistic scenarios of seawater desalination, wastewater treatment, and low-grade environmental energy capture.

[0050] Therefore, the present invention employs the above-mentioned synergistically regulated evaporation-driven power generation hydrogel, its preparation method and application, which enhances power generation performance based on ion specificity effect and photothermal synergistic regulation, maintains stable performance ranking in simulated seawater / sewage, and has strong environmental adaptability.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A synergistically regulated evaporation-driven power generation hydrogel, characterized in that: Includes the polymer matrix and alkali metal ions dispersed in the polymer matrix; The polymer matrix is ​​polyacrylamide hydrogel or polyvinyl alcohol hydrogel, and the alkali metal ion is Li. + Na + or K + One or more of them.

2. The hydrogel for synergistically regulated evaporation-driven power generation according to claim 1, characterized in that: It also includes reduced graphene oxide dispersed in a polymer matrix.

3. A method for preparing a synergistically regulated evaporation-driven power generation hydrogel as described in any one of claims 1 to 2, characterized in that, The preparation of chemically cross-linked alkali metal ion composite polyacrylamide hydrogels using free radical polymerization includes the following steps: S1. Preparation of hydroxypropyl cellulose solution: Add 0.8 to 1 part by weight of hydroxypropyl cellulose powder to 80 to 100 parts of preheated deionized water and stir. S2. Preparation of hydrogel precursor solution: Dissolve 1-2 parts acrylamide, 0.01-0.02 parts N,N'-methylenebisacrylamide and 0.02-0.03 parts initiator in deionized water by weight, and then add alkali metal ion solution and 1 mL of hydroxypropyl cellulose solution obtained in S1. S3. By weight, add 0.001~0.002 parts of N,N,N',N'-tetramethylethylenediamine to the hydrogel precursor solution obtained in S2 to initiate a polymerization reaction and obtain an alkali metal ion composite polyacrylamide hydrogel.

4. The method for preparing a synergistically regulated evaporation-driven power generation hydrogel according to claim 3, characterized in that, In S2, the alkali metal ion solution is one or more of LiCl, NaCl, or KCl solutions, and the concentration of each LiCl, NaCl, or KCl solution is 0.01~0.02 mol·L⁻¹. -1 ; Initiators include ammonium persulfate or potassium persulfate.

5. The method for preparing a synergistically regulated evaporation-driven power generation hydrogel according to claim 3, characterized in that, Before S3, the process also includes adding 0.02 to 0.04 parts by weight of reduced graphene oxide to the hydrogel precursor solution obtained in S2.

6. A method for preparing a synergistically regulated evaporation-driven power generation hydrogel as described in any one of claims 1 to 2, characterized in that, The preparation of physically cross-linked alkali metal ion composite polyvinyl alcohol hydrogels using a cyclic freeze-thaw method includes the following steps: Step 1: Prepare polyvinyl alcohol solution: By weight, slowly add 10-12 parts of PVA powder to 80-100 parts of alkali metal ion solution, stir, let stand, and then place in an oil bath at 90-100℃ and stir continuously at 600 rpm. Step 2: After the polyvinyl alcohol solution obtained in Step 1 has been allowed to stand, it is poured into the mold. Then, the mold containing the PVA solution is placed in a low temperature freezer at -15~-30℃ and frozen. The completely frozen sample is then transferred to room temperature and thawed to obtain an alkali metal ion composite polyvinyl alcohol hydrogel.

7. The application of an evaporation-driven power generation hydrogel prepared by the method of preparing the synergistically regulated evaporation-driven power generation hydrogel according to any one of claims 1 to 2 or the synergistically regulated evaporation-driven power generation hydrogel according to any one of claims 3 to 6 in power generation under infrared light or natural light irradiation.

8. The application according to claim 7, characterized in that, Under infrared light irradiation, a hydration radius of 0.36 nm and an ion mobility range of (5.0~5.5)×10⁻⁶ were used. -8 m 2 ·V -1 ·s -1 , containing Na + The aforementioned evaporation-driven power-generating hydrogel generates electricity through infrared light-induced instantaneous evaporation, the establishment of an ion concentration gradient, and network relaxation efficiency, with an infrared light intensity range of 500~1000 W·m. -2 The evaporation rate of the hydrogel surface is 1.5~2.5 kg·m. -2 ·h -1 ; Alternatively, under natural light irradiation, a hydration radius of 0.33 nm and an ion mobility range of (7.4~7.8)×10⁻⁶ can be used. - 8 m 2 ·V -1 ·s -1 Contains K + The aforementioned evaporation-driven power-generating hydrogel generates electricity through continuous evaporation under natural light, the establishment of an ion concentration gradient, and network relaxation efficiency, with a natural light intensity range of 100~300 W·m. -2 The evaporation rate of the hydrogel surface is 0.3~0.8 kg·m. -2 ·h -1 .

9. The application according to claim 7, characterized in that, A hydration radius of 0.38 nm and an ion mobility range of (3.8~4.2)×10⁻⁶ were used. -8 m 2 ·V -1 ·s -1 Li + The evaporation-driven hydrogel generates electricity through a concentration threshold effect.

10. The application according to claim 7, characterized in that, The evaporation-driven power-generating hydrogel employs alkali metal ions and reduced graphene oxide, wherein the molar number of alkali metal ions is higher than 0.003 mol·L⁻¹. -1 It generates electricity through the photothermal enhancement effect of reduced graphene oxide.

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