Water-induced power generation composite material and preparation method thereof, and power generation device

Abstract

The present application relates to the technical field of functional materials, in particular to a water-induced power generation composite material, a preparation method thereof and a power generation device. The composite material of the present application is sequentially loaded with metal salt and a deposited polymer material layer on the surface, forming a porous positive structure on the surface of the substrate. Meanwhile, one end of the composite material of the present application is coated with a hydrophobic layer, and the other end is a hydrophilic end. When the porous structure of the hydrophilic end interacts with water, the hydrophobic end forms a buffer zone to prevent water from entering. The hydrophilic end and the hydrophobic end automatically form a dry-wet asymmetric structure. After the hydrophilic end contacts water, the metal salt continuously dissociates. The hydrophilic end and the hydrophobic end form an ion concentration gradient, generating electric energy. Compared with the traditional hydrophilic and hydrophobic structure on the upper and lower surfaces, the composite material of the present application has one end hydrophilic and one end hydrophobic on the left and right ends. The ion concentration gradient between the positive and negative electrodes can be maintained for a long time, the chemical energy in water can be continuously and stably converted into electric energy, and the defects of the prior art are overcome.

Description

Technical Field

[0001] This invention relates to the field of functional materials technology, specifically to a water-induced power generation composite material, its preparation method, and a power generation device. Background Technology

[0002] In traditional methods of generating energy from liquid water, the potential energy of water is converted into mechanical energy as it passes through a dam, driving a generator to produce electricity. Water-induced power generation, however, directly converts the chemical energy in water into electrical energy, representing a novel energy harvesting method. Due to the increasingly severe energy shortage problem, the research and application of water-induced power generation has received widespread attention. Water-induced power generation relies on a functional charged porous material that promotes water permeation and proton accumulation on its surface, creating an electrical double layer within capillary channels, thereby generating electricity through a potential difference between the positive and negative electrodes. Compared to traditional piezoelectric materials and triboelectric nanogenerators, it has advantages such as stability and environmental adaptability.

[0003] Water-induced power generation materials are gaining increasing attention because they do not require external mechanical energy to generate electricity, and the electricity they produce is not instantaneous. Currently, such power generation methods largely rely on graphene or carbon-based materials, such as the porous heterogeneous graphene oxide film disclosed in patent WO2020006942A1, the various polymer films disclosed in patent WO2020147443A1 for power generation, the use of protein nanowires to generate electricity from ambient moisture in patent WO2020069523A1, and an innovative polymer material that can be applied to saltwater power generation in patent CN202210577026.7.

[0004] In practical applications, water-induced power generation materials need to maintain a continuous ion concentration gradient to sustain high energy output. When the sample is wetted by water and loses its water gradient, the ion concentration gradient disappears, and its power generation performance rapidly decreases. Therefore, how to maintain an ion concentration gradient within the material to achieve continuous power generation is an urgent problem that water-induced power generation technology needs to solve. A good structural design plays an important role in maintaining continuous power generation. Patent CN 202210472778.7 discloses a method of spraying CB / PVDF onto one side of absorbent paper to form a hydrophobic layer, while the opposite side retains its water-absorbing properties. Water molecules are continuously transported upwards through the hydrophilic surface. Although this top-bottom structure design, with a hydrophobic upper layer and a hydrophilic lower layer, can maintain a dry state for a short period of time, thus maintaining an ion concentration gradient within the material and generating electricity, over a long period of time, water will wet the hydrophobic surface through capillary forces, making it impossible to maintain power output in the long term.

[0005] Therefore, innovative structural design to improve the sustainability and efficiency of water-induced power generation has significant economic and industrial value for expanding the application scope of water-induced power generation materials and collecting energy sources. Summary of the Invention

[0006] In order to overcome the shortcomings of the prior art, one of the objectives of the present invention is to provide a water-induced power generation composite material that, after interacting with water, maintains dry-wet asymmetry for a long time and has continuous and stable water-induced power generation performance.

[0007] The second objective of this invention is to provide a method for preparing water-induced power generation composite materials that is simple to operate and easy to industrialize.

[0008] The third objective of this invention is to provide a power generation device made using the composite material of this invention, which can be applied to power generation in saltwater or freshwater.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] A water-induced power generation composite material includes a substrate, wherein a metal salt is loaded and a polymer layer is deposited on the interior and upper and lower surfaces of the substrate from the inside to the outside; a hydrophobic layer is also provided on the surface of the polymer layer on the upper and lower surfaces of one end of the composite material, while no hydrophobic layer is provided on the upper and lower surfaces of the other end; wherein the polymer layer is formed by in-situ polymerization of metal salt as an initiator.

[0011] Optionally, the metal salt is ferric chloride.

[0012] Optionally, the polymer layer is polypyrrole (PPy).

[0013] Optionally, the hydrophobic layer is an organosilicon coating.

[0014] Optionally, the substrate is a flexible substrate; optionally, the substrate is microfiber nonwoven fabric (MNF); optionally, the thickness of the substrate is 2-5 mm.

[0015] The preparation method of the above-mentioned composite material capable of simultaneously generating electricity and collecting water includes the following steps:

[0016] 1) Substrate pretreatment: Immerse the microfiber nonwoven fabric (MNF) in deionized water and ethanol, ultrasonically treat it to remove surface dirt, dry it, and set it aside;

[0017] 2) Surface modification: The microfiber nonwoven fabric (MNF) treated in step 1) is first soaked in ferric chloride ethanol dispersion and then dried.

[0018] 3) Surface deposition polymerization: The dried nonwoven fabric and pyrrole after step 2) are placed in the same sealed container, and a polypyrrole PPy coating is formed on the surface of the microfiber nonwoven fabric MNF by chemical vapor deposition to obtain PPy@MNF;

[0019] 4) Repeat steps 2) to 3) 3 to 5 times with the PPy@MNF obtained in step 3) to obtain the conductive layer coated composite material.

[0020] 5) Asymmetric modification: The conductive layer obtained in step 4) is coated on one end of the composite material and immersed in an organosilicon solution and dried to obtain the water-induced power generation composite material.

[0021] Optionally, the concentration of the ferric chloride dispersion is 80-100 mg / ml, the soaking time is 3-5 minutes each time, the drying temperature is 50-70℃ each time, and the time is 40-80 minutes.

[0022] Optionally, the volume of pyrrole in the closed chemical vapor deposition container is 8–10 ml;

[0023] Optionally, the vapor deposition polymerization time is 18–24 hours;

[0024] Optionally, the repeated chemical vapor deposition polymerization is performed 3 to 5 times;

[0025] Optionally, the silicone soaking time is 10 to 20 seconds, and it is dried in an oven at 60°C for 5 to 7 hours.

[0026] A power generation device includes multiple power generation units connected in series or in parallel. Each power generation unit includes the aforementioned composite material, wherein the hydrophobic end of the composite material is connected to a first electrode, and the opposite end is connected to a second electrode.

[0027] The composite material provided by this invention features metal salt and polymer layers deposited on the interior and surface of the substrate, forming a surface micro / nano structure that imparts a porous structure and positive charge to the composite material. Simultaneously, this invention incorporates hydrophobic layers on the upper and lower surfaces of one end of the composite material, resulting in one end being hydrophilic and the other hydrophobic. When the hydrophilic end interacts with water, it automatically forms a wet-dry asymmetric structure. After surface modification, the hydrophilic end can continuously dissociate metal salt ions upon contact with water, such as Fe from ferric chloride. 3+ Ions and Cl - The separation of hydrophilic and hydrophobic ends creates an ion concentration gradient on the surface of the composite material. The potential difference generated by the migration of ions on the surface of the composite material allows electrons to flow between the two electrodes through an external circuit, thereby generating electrical energy. In addition, this invention uses metal salts as initiators to form a polymer layer through in-situ polymerization, doping the polymer with metal salt ions to improve the power generation performance of the composite material. Specifically, as an example, the PPy nanolayer prepared by vapor deposition in this invention is doped with ferric chloride ions, which can effectively increase the ion concentration and ion migration rate on the surface of the material during water-induced power generation, thereby improving its performance.

[0028] The conductive coating on the surface of the composite material of this invention, as an example, is a positively charged coating formed by polypyrrole (PPy) and ferric chloride. This coating can adsorb anions in water to form an electrical bilayer, enabling it to induce power generation from both freshwater and saltwater sources. This overcomes the shortcomings of some existing water-induced power generation materials, which rely solely on a single energy source for power generation from saltwater and lack good environmental adaptability.

[0029] Traditional water-induced power generation materials have a hydrophobic layer on the upper surface and a water-absorbing layer on the lower surface, creating an asymmetric ion concentration difference between the two surfaces to generate electricity. When these materials are laid flat on water, the hydrophobic layer on the upper surface remains dry for a short period, maintaining the ion concentration difference between the two surfaces. However, after a while, water wets the hydrophobic surface through capillary action, and the ion concentration difference disappears, making continuous power generation impossible. This invention's composite material breaks away from the structural design of traditional water-induced power generation materials, forming hydrophilic and hydrophobic ends on the left and right sides. The hydrophilic ends, after interacting with water, can maintain the asymmetry between dry and wet for a long time, enabling continuous and stable power generation using fresh or salt water. Specifically, after the hydrophilic ends absorb water, the hydrophobic ends formed by the silicone coating, etc., create a buffer zone that prevents water from continuously transporting upwards, maintaining the ion concentration gradient between the positive and negative electrodes for a long time, achieving a continuous and stable conversion of chemical energy in water into electrical energy, overcoming the shortcomings of existing technologies. Attached Figure Description

[0030] Figure 1 A schematic diagram of the composite material preparation process provided in Example 1;

[0031] Figure 2 Scanning electron microscope image of the composite material provided in Example 1;

[0032] Figure 3 A schematic diagram showing the verification results of the freshwater induced power generation performance of the composite material provided in Example 1;

[0033] Figure 4 A schematic diagram showing the verification results of the salt water induced power generation performance of the composite material provided in Example 1;

[0034] Figure 5 This is a schematic diagram of the verification results of the salt water induced power generation performance of the composite material provided in Example 2;

[0035] Figure 6 This is a schematic diagram of the power generation device assembled from composite materials provided in Example 3;

[0036] Figure 7 A schematic diagram showing the verification results of the salt water induced power generation performance of the composite material provided in Comparative Example 1;

[0037] Figure 8A schematic diagram showing the verification results of the salt water induced power generation performance of the composite material provided for Comparative Example 2. Detailed Implementation

[0038] The present invention will be further described in detail below with reference to specific embodiments. Unless otherwise specified, the equipment and reagents used in the embodiments and test examples are commercially available. MNF is a household microfiber nonwoven fabric.

[0039] Example 1

[0040] This embodiment provides a composite material for water-induced power generation, using 3mm thick MNF as the substrate, with ferric chloride loaded on the surface and PPy coating deposited thereon; an organosilicon hydrophobic layer is formed on the surface of the PPy coating on the upper and lower surfaces of one end of the composite material, while no hydrophobic layer is provided on the other end.

[0041] The composite material provided in this embodiment can be used for freshwater or saltwater power generation, and its preparation process is as follows: Figure 1 As shown, the specific operation steps are as follows:

[0042] 1) MNF cleaning treatment:

[0043] Cut 3mm thick microfiber nonwoven fabric (MNF) into 20mm*40mm rectangles, then place them in deionized water and ethanol and sonicate for 20 minutes to remove dirt from the MNF surface. Then dry them in an oven at 70℃ for later use.

[0044] 2) Surface modification: Ferric chloride was ultrasonically dispersed in ethanol for 10 min to form ferric chloride ethanol dispersion with a concentration of 100 mg / mL;

[0045] After cleaning in step 1), the MNF was immersed in ferric chloride ethanol dispersion for 5 minutes to immerse its upper and lower surfaces in a layer of ferric chloride ethanol dispersion, and then dried in an oven at 70°C for 60 minutes.

[0046] 3) Surface deposition polymerization: The dried nonwoven fabric after step 2) was placed in a sealed large petri dish, and then a small petri dish containing 10 ml of pyrrole was placed in the large petri dish for vapor deposition polymerization of PPy for 24 hours to obtain PPy@MNF;

[0047] 4) Repeat steps 2) to 3) 4 times to obtain a conductive layer coated composite material sample.

[0048] 5) Asymmetric modification: Immerse one end of the water-induced power generation composite material obtained in step 4) in an organosilicon solution for 10 seconds, and dry it in an oven at 60°C for 5 hours to obtain the composite material.

[0049] Test case

[0050] 1. Surface structure characterization:

[0051] like Figure 2 As shown in the comparison of scanning electron microscope images of the hydrophilic region (opposite end of the organosilicon layer) and the hydrophobic region (end of the organosilicon layer) of the composite material provided in Example 1, the hydrophilic region has a large number of capillary channels, and the pores of the organosilicon layer end are covered. When the hydrophilic end interacts with water, the positively charged nanoparticles in the capillary channels adsorb anions in the water to form an electric bilayer. The organosilicon layer end prevents water from continuously transporting upward, and maintains the dry-wet asymmetry. A proton concentration gradient is generated between the hydrophilic end and the hydrophobic end, which can realize continuous power generation.

[0052] 2. Power generation performance characterization:

[0053] 1) Freshwater induced power generation:

[0054] Using the composite material provided in Example 1, the hydrophilic end and hydrophobic end are connected to the positive and negative electrodes respectively to assemble a power generation unit. The output voltage signal of the hydrophilic end interacting with fresh water is as follows: Figure 3 As shown, the composite material provided in this embodiment can achieve freshwater-induced continuous power generation.

[0055] 2) Saltwater power generation:

[0056] Using the composite material provided in Example 1, the hydrophilic end and hydrophobic end are connected to the positive and negative electrodes respectively to assemble a power generation unit. After the hydrophilic end reacts with a 3.5% sodium chloride aqueous solution, the output current signal is as follows: Figure 4 As shown, the composite material provided in this embodiment can achieve saltwater-induced continuous power generation.

[0057] Example 2

[0058] This embodiment provides a composite material for water-induced power generation, using MNF with a thickness of 2mm as the substrate, with ferric chloride loaded on the surface and PPy coating deposited thereon; an organosilicon hydrophobic layer is formed on the surface of the PPy coating on the upper and lower surfaces of one end of the composite material, while no hydrophobic layer is provided on the other end.

[0059] The composite material provided in this embodiment can be used for freshwater or saltwater power generation, and its preparation process is as follows: Figure 1 As shown, the specific operation steps are as follows:

[0060] 1) MNF cleaning treatment:

[0061] The 3mm thick microfiber was cut into 20mm*40mm rectangles, then placed in deionized water and ethanol and sonicated for 20 minutes to remove dirt from the MNF surface. It was then dried in an oven at 70℃ for later use.

[0062] 2) Surface modification: Ferric chloride was ultrasonically dispersed in ethanol for 10 min to form ferric chloride ethanol dispersion with a concentration of 80 mg / mL;

[0063] After cleaning in step 1), the MNF was immersed in ferric chloride ethanol dispersion for 4 minutes to immerse its upper and lower surfaces in a layer of ferric chloride ethanol dispersion, and then dried in an oven at 70°C for 60 minutes.

[0064] 3) Surface deposition polymerization: The dried nonwoven fabric after step 2) was placed in a sealed large petri dish, and then a small petri dish containing 8 ml of pyrrole was placed in the large petri dish for vapor deposition polymerization of PPy for 18 hours to obtain PPy@MNF;

[0065] 4) Repeat steps 2) to 3) 5 times to obtain a conductive layer coated composite material sample.

[0066] 5) Asymmetric modification: Immerse one end of the water-induced power generation composite material obtained in step 4) in an organosilicon solution for 10 seconds, and dry it in an oven at 60°C for 7 hours to obtain the composite material.

[0067] Experimental Example 2

[0068] Power generation performance characterization:

[0069] 1) Freshwater induced power generation:

[0070] Using the composite material provided in Example 2, the hydrophilic end and the hydrophobic end are connected to the positive and negative electrodes respectively to assemble a power generation unit. The hydrophilic end interacts with fresh water, and the power generation data tested is shown in Table 1, indicating that the composite material provided in this example can achieve stable and continuous power generation induced by fresh water.

[0071] Table 1

[0072] sample <![CDATA[V oc ]]> <![CDATA[I sc ]]> Duration Example 2 0.62V 160μA 1 hour

[0073] 2) Saltwater power generation:

[0074] Using the composite material provided in Example 2, the output voltage signal after the hydrophilic end reacts with a 3.5% sodium chloride aqueous solution is as follows: Figure 5 As shown, the composite material provided in this embodiment can achieve stable and continuous power generation induced by salt water.

[0075] Example 3

[0076] This embodiment provides a composite material for water-induced power generation, using 5mm thick MNF as the substrate, with ferric chloride loaded on the surface and PPy coating deposited thereon; an organosilicon hydrophobic layer is formed on the surface of the PPy coating on the upper and lower surfaces of one end of the composite material, while no hydrophobic layer is provided on the other end.

[0077] The composite material provided in this embodiment can be used for freshwater or saltwater power generation, and its preparation process is as follows: Figure 1 As shown, the specific operation steps are as follows:

[0078] 1) MNF cleaning treatment:

[0079] The 3mm thick microfiber was cut into 20mm*40mm rectangles, then placed in deionized water and ethanol and sonicated for 20 minutes to remove dirt from the MNF surface. It was then dried in an oven at 70℃ for later use.

[0080] 2) Surface modification: Ferric chloride was ultrasonically dispersed in ethanol for 10 min to form ferric chloride ethanol dispersion with a concentration of 90 mg / mL;

[0081] After cleaning in step 1), the MNF was immersed in ferric chloride ethanol dispersion for 4 minutes to immerse its upper and lower surfaces in a layer of ferric chloride ethanol dispersion, and then dried in an oven at 70°C for 65 minutes.

[0082] 3) Surface deposition polymerization: The dried nonwoven fabric after step 2) was placed in a sealed large petri dish, and then a small petri dish containing 9 ml of pyrrole was placed in the large petri dish for vapor deposition polymerization of PPy for 20 hours to obtain PPy@MNF;

[0083] 4) Repeat steps 2) to 3) three times with the PPy@MNF obtained in step 3) to obtain a conductive layer coated composite material sample.

[0084] 5) Asymmetric modification: Immerse one end of the water-induced power generation composite material obtained in step 4) in an organosilicon solution for 10 seconds, and dry it in an oven at 60°C for 6 hours to obtain the composite material.

[0085] Experimental Example 3

[0086] Power generation performance characterization:

[0087] Using the composite material provided in Example 3, the hydrophilic end and hydrophobic end are connected to the positive and negative electrodes respectively to assemble a power generation unit, which is further assembled into... Figure 6 The power generation device shown can drive the calculator to operate stably after the hydrophilic end interacts with a 3.5% sodium chloride aqueous solution, indicating that the composite material provided in this embodiment can achieve stable and continuous power generation induced by salt water.

[0088] The results of the examples and experiments show that the composite material provided by the present invention can continuously collect the minute energy generated when water interacts with fabric, exhibiting high performance and high stability in water-induced power generation, thus increasing the pathway for converting chemical energy in water into electrical energy. Comparative Example 1

[0089] This comparative example provides a composite material for water-induced power generation, using 3mm thick MNF as the substrate, with ferric chloride and PPy coating sequentially loaded on the surface.

[0090] The composite material provided in this comparative example can only generate electricity for a short time. The specific operating steps are as follows:

[0091] 1) MNF cleaning treatment:

[0092] Cut 3mm thick microfiber into 20mm*40mm rectangular shapes, then place them in deionized water and ethanol and sonicate for 20 minutes to remove dirt from the surface of the microfiber nonwoven fabric. Dry them in an oven at 70℃ for later use.

[0093] 2) Surface modification: Ferric chloride was ultrasonically dispersed in ethanol for 10 min to form ferric chloride ethanol dispersion with a concentration of 100 mg / mL;

[0094] The ultrafine nonwoven fabric after cleaning in step 1) was immersed in ferric chloride ethanol dispersion for 5 minutes, so that the upper and lower surfaces were immersed in a layer of ferric chloride ethanol dispersion, and then dried in an oven at 70°C for 60 minutes.

[0095] 3) Surface deposition polymerization: The dried nonwoven fabric after step 2) was placed in a sealed large petri dish, and then a small petri dish containing 10 ml of pyrrole was placed in the large petri dish for vapor deposition polymerization of PPy for 24 hours to obtain PPy@MNF;

[0096] 4) The PPy@MNF obtained in step 3) is repeated 4 times according to steps 2) to 3) to obtain the composite material.

[0097] Comparative Example 1

[0098] Power generation performance characterization:

[0099] Using the composite material provided in Comparative Example 1, a power generation unit was assembled by connecting the positive and negative electrodes at the top and bottom ends, respectively, for testing. The hydrophilic end was reacted with a 3.5% sodium chloride aqueous solution, such as... Figure 7 As shown, its voltage drops rapidly to 200mV after reaching 600mV, and can only maintain power generation for a short time, indicating that the asymmetric structure plays an important role in maintaining high voltage output.

[0100] Comparative Example 2

[0101] This comparative example provides a composite material for water-induced power generation, using MNF with a thickness of 3 mm as the substrate, on which ferric chloride is loaded and PPy coating is deposited sequentially; residual ferric chloride is removed, and then an organosilicon hydrophobic layer is formed on the surface of the PPy coating on the upper and lower surfaces of one end of the composite material, while no hydrophobic layer is provided on the other end.

[0102] The composite material provided in this comparative example has low power generation performance. The specific operating steps are as follows:

[0103] 1) MNF cleaning treatment:

[0104] Cut 3mm thick microfiber into 20mm*40mm rectangular shapes, then place them in deionized water and ethanol and sonicate for 20 minutes to remove dirt from the surface of the microfiber nonwoven fabric. Dry them in an oven at 70℃ for later use.

[0105] 2) Surface modification: Ferric chloride was ultrasonically dispersed in ethanol for 10 min to form ferric chloride ethanol dispersion with a concentration of 100 mg / mL;

[0106] The ultrafine nonwoven fabric after cleaning in step 1) was immersed in ferric chloride ethanol dispersion for 5 minutes, so that the upper and lower surfaces were immersed in a layer of ferric chloride ethanol dispersion, and then dried in an oven at 70°C for 60 minutes.

[0107] 3) Surface deposition polymerization: The dried nonwoven fabric after step 2) was placed in a sealed large petri dish, and then a small petri dish containing 10 ml of pyrrole was placed in the large petri dish for vapor deposition polymerization of PPy for 24 hours. The resulting composite material sample was then placed in deionized water and ultrasonically cleaned for 30 min to remove residual ferric chloride. Finally, it was placed in an oven at 70°C for 5 h to obtain PPy@MNF.

[0108] 4) Repeat steps 2) to 3) 4 times to obtain a conductive layer coated composite material sample.

[0109] 6) Asymmetric modification: Immerse one end of the water-induced power generation composite material obtained in step 5) in an organosilicon solution for 10 seconds, and dry it in an oven at 60°C for 5 hours to obtain the composite material.

[0110] Comparative Example 2

[0111] Power generation performance characterization:

[0112] Using the composite material provided in Comparative Example 2, the hydrophilic and hydrophobic ends were connected to the positive and negative electrodes respectively to assemble a power generation unit. The hydrophilic end reacted with a 3.5% sodium chloride aqueous solution, and the tested power generation data are as follows: Figure 8 As shown, its power generation current is low, indicating that the presence of metal salts, such as ferric chloride, in this invention is crucial for improving power generation performance.

[0113] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A water-induced power-generating composite material, characterized by, The composite material comprises a substrate, the inside and upper and lower surfaces of the substrate are sequentially loaded with metal salt and a polymer layer deposited in-situ, and a hydrophobic layer is arranged on the surface of the polymer layer on one end of the composite material, and no hydrophobic layer is arranged on the upper and lower surfaces of the opposite end. The polymer layer is formed by in-situ polymerization of the metal salt as an initiator, specifically, the substrate is soaked in a dispersion liquid containing the metal salt to complete the loading of the metal salt, and then the polymer layer is formed by in-situ polymerization and deposition on the surface of the substrate, and no cleaning treatment is performed on the surface. The metal salt is ferric chloride, and the polymer layer is a polypyrrole PPy layer.

2. The water-induced power-generating composite material of claim 1, wherein, The substrate is a flexible substrate.

3. The water-induced power-generating composite material of claim 2, wherein, The substrate is a microfiber non-woven fabric MNF.

4. The water-induced power-generating composite material of claim 3, wherein, The thickness of the substrate is 2mm-5mm.

5. The water-induced power-generating composite material according to claim 3 or 4, wherein, The hydrophobic layer is an organic silicon coating.

6. A method of preparing a water-induced power-generating composite material as claimed in claim 5, characterized by, The method comprises the following operation steps: 1) substrate pretreatment: the microfiber non-woven fabric MNF is immersed in deionized water and ethanol, ultrasonic treatment is performed, surface dirt is removed, and drying is performed, and the microfiber non-woven fabric MNF is prepared for use; 2) surface modification: the microfiber non-woven fabric MNF treated in step 1) is first soaked in a ferric chloride ethanol dispersion liquid, and drying treatment is performed; 3) surface deposition and polymerization: the microfiber non-woven fabric MNF treated and dried in step 2) and pyrrole are placed in the same sealed container, a polypyrrole PPy coating is formed on the surface of the microfiber non-woven fabric MNF by chemical vapor deposition polymerization, and a PPy@MNF is obtained; 4) the PPy@MNF prepared in step 3) is repeatedly cycled 3-5 times according to steps 2) to 3) to obtain a conductive layer coated composite material; 5) asymmetric modification: one end of the conductive layer coated composite material prepared in step 4) is soaked in an organic silicon solution, and drying treatment is performed, and the water-induced power generation composite material is prepared.

7. The method for preparing the water-induced power generation composite material as described in claim 6, characterized in that, In step 2), the concentration of the ferric chloride dispersion liquid is 80-100mg / ml, the soaking time is 3-5 minutes each time, and the drying temperature is 50-70°C, and the time is 20-30 minutes.

8. The method for preparing the water-induced power generation polymer material as described in claim 7, characterized in that, In step 3), the chemical vapor deposition polymerization time is 18-24 hours; in step 4), the number of repeated cycles of chemical vapor deposition polymerization is 3-5 times; the organic silicon soaking time is 10-20 seconds, and the organic silicon is placed in an oven at 60°C for drying for 5-7 hours.

9. A power generation device characterized by comprising: The power generation unit comprises the composite material as claimed in any one of claims 1-4, and one end of the composite material is connected with a first electrode, and the opposite end is connected with a second electrode.

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