Negative electrode structure of friction nano-generator and preparation method and application of negative electrode structure

Abstract

The invention provides a friction nanometer generator negative electrode structure and a preparation method and application thereof. The preparation method comprises the following steps: mixing a PDMS prepolymer, a curing agent and ZnS: Cu particles to form a PDMS solution I, putting the PDMS solution I into a mold I, and drying to obtain a luminescent film; a PDMS prepolymer, a curing agent and magnetic powder are mixed to form a second PDMS solution, the light-emitting film is flatly laid in a second mold, then the second PDMS solution is placed in the second mold, drying treatment is conducted after magnetizing, a magnetic field in the preset direction is set during drying treatment, the magnetic powder grows upwards to form a whisker-shaped magnetized microcilium array, and the friction nanometer generator negative electrode structure is obtained. Through the mode, the PDMS film which can emit light in the pressing and stretching process and is provided with the whisker-shaped magnetized micro-cilia array on the surface can be prepared with a simple method and low cost, so that the PDMS film can be applied to a friction nano-generator as a negative electrode structure, and the output electrical performance of the friction nano-generator is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of triboelectric nanogenerators, and particularly to a negative electrode structure of a triboelectric nanogenerator, a preparation method thereof, and an application thereof. Background Art

[0002] With the development of the Internet of Things (IoT), smart devices, wearable technologies, and electronic products, they consume a large amount of electricity and are difficult to operate for a long time. Therefore, it is necessary to frequently charge these devices for a long time, which hinders their wide application. Currently, we are using excessive energy from fossil fuels and various metals, which have caused serious environmental problems on the earth, such as barren land, climate change, global warming, and increased carbon emissions. In order to reduce carbon emissions and protect our environment, renewable energy harvesting technologies will become the key solutions in the near future. Among them, the triboelectric nanogenerator (TENG) is one of the most promising mechanical energy harvesters for contact electrification. Due to its ability to harvest abundant wasted mechanical energy, and having a series of advantages such as wide material availability and selection range, relatively simple device configuration, and low processing cost, it is currently experiencing explosive development.

[0003] The triboelectric nanogenerator mainly utilizes the triboelectric effect, which is the coupled effect of contact electrification and electrostatic induction between two opposite surface-charged materials, causing charge generation from friction. In electromagnetic devices, electromagnetic induction is the key to converting mechanical energy into electrical energy. These mechanical-to-electrical conversion mechanisms can provide a good platform for sensor and energy harvesting applications, generating renewable transparent electrical energy using the available mechanical input sources in the use environment.

[0004] In the prior art, the patent with the publication number CN115242119A provides a preparation method and device for a triboelectric nanogenerator with a microcone nanoparticle structure. This patent uses a precision engraving machine to machine a conical microcolumn array on the top of an acrylic plate to prepare a microcone structure template, uses the template method to assist the self-assembly of a vertical downward magnetic field to prepare a carbonyl iron powder / polydimethylsiloxane (PDMS) composite microcone film, uses the dip coating method to assist adsorption to prepare a microcone nanoparticle structure composite film, and connects the microcone nanoparticle structure composite film with an external circuit printed circuit board through a current collector wire to prepare a triboelectric nanogenerator for collecting distributed energy. However, this method requires pre-preparing a microcone structure template, the preparation method is complex and the cost is higher, and the formed microcone structure can only increase the contact area between the friction material pairs to a certain extent, and the improvement of the electrical output performance of the triboelectric nanogenerator is not obvious enough. How to prepare the corresponding negative electrode structure in a lower-cost and more convenient operation manner, and more effectively improve the output electrical performance of the triboelectric nanogenerator is still an urgent problem to be solved currently.

[0005] In view of this, it is necessary to design an improved negative electrode structure of a triboelectric nanogenerator, its preparation method and application to solve the above problems. Summary of the Invention

[0006] Aiming at the defects of the above-mentioned prior art, the purpose of the present invention is to provide a negative electrode structure of a triboelectric nanogenerator, its preparation method and application. By doping ZnS:Cu particles in a thin film substrate to form a light-emitting film, and loading a PDMS solution containing magnetic powder on the surface of the light-emitting film, a whisker-shaped magnetized microfibril array can be formed on the surface under the induction of a magnetic field, so that the prepared negative electrode structure can emit light during the pressing and stretching process, and realize the separation between the positive and negative electrodes of the triboelectric nanogenerator device, effectively improving the output electrical performance of the triboelectric nanogenerator.

[0007] To achieve the above object, the present invention provides a preparation method of a negative electrode structure of a triboelectric nanogenerator, including the following steps:

[0008] S1. Mix PDMS prepolymer, curing agent and ZnS:Cu particles evenly according to a predetermined mass ratio to obtain PDMS solution one;

[0009] S2. Place the PDMS solution one in mold one, and obtain a light-emitting film after drying;

[0010] S3. Mix PDMS prepolymer, curing agent and magnetic powder evenly according to a predetermined mass ratio to obtain PDMS solution two;

[0011] S4. Lay the light-emitting film flat in mold two, then place the PDMS solution two in mold two, perform drying treatment after magnetization, and set a magnetic field in a predetermined direction during the drying treatment so that the magnetic powder grows upward to form a whisker-shaped magnetized microfibril array, obtaining a negative electrode structure of a triboelectric nanogenerator.

[0012] As a further improvement of the present invention, in step S1, in the PDMS solution one, the mass ratio of the PDMS prepolymer to the curing agent is 10:1, and the mass ratio of the PDMS prepolymer to the ZnS:Cu particles is 1:9 - 8:2.

[0013] As a further improvement of the present invention, the mass ratio of the PDMS prepolymer to the ZnS:Cu particles is 3:7 - 7:3.

[0014] As a further improvement of the present invention, in step S2, the average thickness of the light-emitting film is 0.12 - 0.36 mm.

[0015] As a further improvement of the present invention, in step S3, in the second PDMS solution, the mass ratio of the PDMS prepolymer to the curing agent is 10:1, and the mass fraction of the magnetic powder in the PDMS prepolymer is 40% to 70%.

[0016] As a further improvement of the present invention, in step S4, in step S4, the bottom diameter of the whisker-shaped magnetized microcilia is 1.1 to 2.3 mm, and the height is 4.4 to 6.5 mm; the average distance between adjacent whisker-shaped magnetized microcilia is 1.1 to 2.0 mm.

[0017] As a further improvement of the present invention, the dosage ratio of the first PDMS solution to the second PDMS solution is 1:2.

[0018] As a further improvement of the present invention, the size of the second mold is larger than that of the first mold.

[0019] The present invention also provides a triboelectric nanogenerator negative electrode structure prepared by any one of the above technical solutions.

[0020] The present invention also provides an application of the above triboelectric nanogenerator negative electrode structure in a triboelectric nanogenerator.

[0021] The beneficial effects of the present invention are:

[0022] The preparation method of the triboelectric nanogenerator negative electrode structure provided by the present invention forms a light-emitting film by doping ZnS:Cu particles in a thin film substrate, and loads a PDMS solution containing magnetic powder on the surface of the light-emitting film, and then forms a PDMS film with a whisker-shaped magnetized microcilia array on the surface by the induction of a magnetic field. As the triboelectric nanogenerator negative electrode structure, the PDMS film can not only emit light during the pressing and stretching process, realizing excellent handwriting input performance to display different input contents; but also can be used as the friction layer material of the triboelectric nanogenerator in the triboelectric nanogenerator. The whisker-shaped magnetized microcilia array on its surface can not only effectively increase the contact area of the friction layer during the friction process, but also realize the separation between the positive and negative electrodes of the triboelectric nanogenerator device, enabling the triboelectric nanogenerator to generate electricity through the vertical separation mode, effectively improving the output electrical performance of the triboelectric nanogenerator. Moreover, the preparation method provided by the present invention is simple and easy to operate, has a low cost, high controllability, and the prepared triboelectric nanogenerator negative electrode structure can effectively improve its output electrical performance when applied to the triboelectric nanogenerator, and has better wearable performance, meeting the requirements of practical applications. Description of the Drawings

[0023] Figure 1 3D microscope image of the triboelectric nanogenerator negative electrode structure prepared in Example 1.

[0024] Figure 2 The luminescence effect diagram of the negative electrode structure of the triboelectric nanogenerator prepared in Example 1.

[0025] Figure 3 The overall schematic diagram of the TENG device.

[0026] Figure 4 The output voltage diagram of the TENG assembled with the negative electrode structure of the triboelectric nanogenerator prepared in Example 1.

[0027] Figure 5 The stability test result diagram of the TENG assembled with the negative electrode structures of the triboelectric nanogenerators prepared in Comparative Example 1, Example 2, and Example 3 under the conditions of a frequency of 5 Hz and a pressing depth of 100%. Detailed implementation manners

[0028] In order to make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] Here, it should also be noted that in order to avoid obscuring the present invention due to unnecessary details, only the structures and / or processing steps closely related to the solution of the present invention are shown in the drawings, while other details less related to the present invention are omitted.

[0030] In addition, it should also be noted that the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0031] The present invention provides a preparation method for a negative electrode structure of a triboelectric nanogenerator, comprising the following steps:

[0032] S1. Mix PDMS prepolymer, curing agent, and ZnS:Cu particles evenly according to a predetermined mass ratio to obtain PDMS solution I;

[0033] S2. Place the PDMS solution I in mold I, and obtain a luminescent film after drying;

[0034] S3. Mix PDMS prepolymer, curing agent, and magnetic powder evenly according to a predetermined mass ratio to obtain PDMS solution II;

[0035] S4. Lay the luminescent film flat in mold II, then place the PDMS solution II in mold II, perform magnetization after charging and then drying treatment, and set a magnetic field in a predetermined direction during the drying treatment so that the magnetic powder grows upward to form a whisker-shaped magnetized microfibril array, and obtain a PDMS thin film, which is the negative electrode structure of the triboelectric nanogenerator.

[0036] In the above - mentioned way, on the one hand, ZnS:Cu particles can be doped into the thin - film substrate, enabling triboluminescence between PDMS and ZnS:Cu. Under such conditions, when operations such as pressing and stretching are performed on the thin film, the ZnS:Cu particles can rub against PDMS, causing energy - level transitions in ZnS:Cu and generating light of different wavelengths. On the other hand, by inducing the directional movement of magnetic powder during the drying process, a whisker - shaped magnetized micro - fibril array can be formed on the surface of the thin film. When this PDMS thin film is applied to a triboelectric nanogenerator, this whisker - shaped magnetized micro - fibril array can not only effectively increase the contact area of the friction layer during the friction process but also realize the separation between the positive and negative electrodes of the triboelectric nanogenerator device, enabling the triboelectric nanogenerator to generate electricity through a vertical separation mode. By using the contact - separation of the positive and negative electrodes to make the positive electrode carry positive charges and the negative electrode carry negative charges, electricity is generated through the potential difference, effectively improving the output electrical performance of the triboelectric nanogenerator.

[0037] Specifically, in step S1, the mass ratio of the PDMS prepolymer to the curing agent in PDMS solution one is 10:1, and the mass ratio of the PDMS prepolymer to ZnS:Cu particles is 1:9 - 8:2, and preferably 3:7 - 7:3 to achieve a better light - emitting effect. Among them, ZnS:Cu is zinc sulfide doped with copper elements, and the particle size of the ZnS:Cu particles is preferably 20μm. When blending the PDMS prepolymer, the curing agent, and ZnS:Cu, ultrasonic treatment for 5 - 15 min is preferably used to mix them evenly.

[0038] In step S2, the preferred drying conditions are drying in an oven at 70 - 90°C for 1.5 - 2.5 h. By controlling the dosage of PDMS solution one and the size of mold one, the average thickness of the light - emitting film is regulated to 0.12 - 0.36 mm. With such settings, it has the effects of good light - emitting intensity and raw material saving.

[0039] In step S3, the mass ratio of the PDMS prepolymer to the curing agent in PDMS solution two is 10:1, and the mass fraction of the magnetic powder in the PDMS prepolymer is 40% - 70%. Among them, the type of magnetic powder is preferably NdFeB bonded magnetic powder, and the average particle size of the magnetic powder is preferably 40 - 420μm.

[0040] Preferably, when preparing this PDMS, the dosage ratio of PDMS solution one to PDMS solution two is controlled to be 1:2, and the size of mold two is made larger than the size of mold one. With such settings, the thickness of the negative electrode can be effectively controlled to achieve the effect of increasing the voltage. When blending the PDMS prepolymer, the curing agent, and the magnetic powder, mechanical stirring for 5 - 15 min is preferably used, and the stirring speed is controlled at 80 - 120 rpm to mix them evenly.

[0041] In step S4, the conditions for the drying treatment are preferably drying in an oven at 70-90 °C for 1.5-2.5 h. During this drying treatment process, the set magnetic field strength is preferably 90-130 T.

[0042] By adjusting parameters such as the mass fraction of magnetic powder, magnetic field strength, and drying conditions, the present invention can control the size of the formed whisker-shaped magnetized microcilia. Preferably, the bottom diameter of the whisker-shaped magnetized microcilia is 1.1-2.3 mm, and the height is 4.4-6.5 mm; the distance between adjacent whisker-shaped magnetized microcilia is 1.1-2.0 mm. Under these conditions, the formed whisker-shaped magnetized microcilia have a relatively high height and can increase the density, thereby generating a greater frictional effect between the cilia and the positive electrode.

[0043] Based on the above method, the negative electrode structure of the triboelectric nanogenerator prepared by the present invention can be applied to the preparation of triboelectric nanogenerators.

[0044] The following specifically describes the negative electrode structure of the triboelectric nanogenerator provided by the present invention, its preparation method and application, in combination with specific examples and comparative examples.

[0045] Example 1

[0046] This example provides a preparation method for the negative electrode structure of a triboelectric nanogenerator, including the following steps:

[0047] S1. Mix the PDMS prepolymer, curing agent, and ZnS:Cu particles, and then ultrasonically treat for 10 min to make them evenly mixed, obtaining PDMS solution I. Among them, the mass ratio of the PDMS prepolymer to the curing agent is 10:1, and the mass ratio of the PDMS prepolymer to the ZnS:Cu particles is 6:4; the particle size of the ZnS:Cu particles used in this example is 20 μm.

[0048] S2. Spread PDMS solution I with a glass rod in a square mold I surrounded by cover glasses, place it in an oven at 80 °C and dry for 2 h, then cut open the surroundings with a knife and take it out to obtain a light-emitting film. The average thickness of this light-emitting film is 0.24 mm.

[0049] S3. Mix the PDMS prepolymer, curing agent, and magnetic powder, and then mechanically stir at a speed of 100 rpm for 10 min to make them evenly mixed, obtaining PDMS solution II. Among them, the mass ratio of the PDMS prepolymer to the curing agent is 10:1, and the mass fraction of the magnetic powder in the PDMS prepolymer is 60%; the type of magnetic powder used in this example is NdFeB neodymium iron boron bonded magnetic powder, and the average particle size of this magnetic powder is 50 μm; the dosage ratio of PDMS solution I to PDMS solution II is 1:2.

[0050] S4. Lay the light-emitting film flat in Mold 2, where the size of Mold 2 is larger than that of Mold 1. Then, place the PDMS solution 2 in Mold 2. After magnetization, put it into an oven at 80 °C for drying treatment for 2 h, and place a magnet on the oven during the drying treatment to form a magnetic field with a strength of 110 T, so that the magnetic powder grows upward to form a whisker-like magnetized microfiber array, obtaining a PDMS thin film, which is the negative electrode structure of the triboelectric nanogenerator. Its 3D microscope image is as shown in Figure 1 shown.

[0051] It can be seen from Figure 1 that the negative electrode structure of the triboelectric nanogenerator prepared in this embodiment includes a PDMS base film with a thickness of about 0.5 mm and a whisker-like magnetized microfiber array perpendicular to the surface of the base film. The bottom diameter of the whisker-like magnetized microfiber is about 1.1 - 2.3 mm, and the height is about 4.4 - 6.5 mm; the spacing between adjacent whisker-like magnetized microfibers is about 1.1 - 2.0 mm.

[0052] Press and stretch the negative electrode structure of the triboelectric nanogenerator prepared in this embodiment, and it can emit light. The light-emitting effect is as shown in Figure 2 shown.

[0053] This embodiment also provides the application of the prepared negative electrode structure of the triboelectric nanogenerator in a triboelectric nanogenerator (TENG), which specifically includes the following steps:

[0054] Weave the yarn into a core-shell structured yarn with Cu as the core and the yarn as the shell through a simple weaving structure, and prepare it into a fabric as the positive electrode. Then, use the prepared PDMS thin film as the negative electrode to assemble a triboelectric nanogenerator. Among them, the assembly method of the positive electrode and the negative electrode includes winding and covering the negative electrode on the outside of the positive electrode, or laying the negative electrode flat on the positive electrode fabric, with the magnetized microfibers in the negative electrode facing the positive electrode. Its schematic diagram is as shown in Figure 3 shown. By pressing and patting the triboelectric nanogenerator, an electrical signal can be generated.

[0055] Specifically in this embodiment, the yarn used is cotton thread. In other embodiments, yarns of other materials such as nylon thread and polyurethane fiber can also be selected; in this embodiment, the negative electrode is laid flat on the positive electrode fabric. In other embodiments, other assembly methods can also be used, as long as the magnetized microfibers in the negative electrode face the positive electrode, and the positive electrode and the negative electrode generate electricity through the vertical separation mode.

[0056] Connect the TENG assembled in the above steps to a circuit board. The pressing test results at a frequency of 5 Hz are as shown in Figure 4 shown. It can be seen from Figure 4 that the TENG assembled in this embodiment has good output electrical performance.

[0057] Comparative Example 1

[0058] This comparative example provides a method for preparing the negative electrode structure of a triboelectric nanogenerator. Compared with Example 1, the difference lies in that when preparing PDMS solution II in step S3, magnetic powder was not added, and the remaining steps are the same as those in Example 1, which will not be elaborated here.

[0059] The surface of the negative electrode structure of the triboelectric nanogenerator prepared in this comparative example has no whisker-shaped magnetized microcilia array.

[0060] Examples 2 - 3

[0061] Examples 2 - 3 respectively provide a method for preparing the negative electrode structure of a triboelectric nanogenerator. Compared with Example 1, the difference lies in changing the mass ratio of PDMS prepolymer and ZnS:Cu particles in PDMS solution I, and the mass fraction of magnetic powder in PDMS prepolymer in PDMS solution II. The remaining steps are the same as those in Example 1, which will not be elaborated here.

[0062] Among them, in Example 2, the mass ratio of PDMS prepolymer and ZnS:Cu particles is 5:5, and the mass fraction of magnetic powder in PDMS prepolymer is 40%; in Example 3, the mass ratio of PDMS prepolymer and ZnS:Cu particles is 6:4, and the mass fraction of magnetic powder in PDMS prepolymer is 60%.

[0063] The surfaces of the negative electrode structures of the triboelectric nanogenerators prepared in Examples 2 - 3 all have whisker-shaped magnetized microcilia arrays. Moreover, the higher the mass fraction of magnetic powder, the larger the size and the higher the height of the formed whisker-shaped magnetized microcilia. The size of the whisker-shaped magnetized microcilia on the surface of the negative electrode structure prepared in Example 3 is similar to that in Example 1, indicating that the structure of the whisker-shaped magnetized microcilia is mainly related to the mass fraction of magnetic powder in PDMS prepolymer in PDMS solution II and has nothing to do with the mass ratio of PDMS prepolymer and ZnS:Cu particles in PDMS solution I.

[0064] According to the same assembly method as in Example 1, the negative electrode structures of the triboelectric nanogenerators prepared in Comparative Example 1 and Examples 2 - 3 were respectively assembled into TENGs, and under the same test conditions, the output voltage performance of the TENGs assembled in Comparative Example 1 and Examples 2 - 3 was tested. The results are as Figure 5 shown.

[0065] From Figure 5It can be seen that as the mass fraction of magnetic powder increases, the output electrical performance of the TENG assembled based on the negative electrode structure of this triboelectric nanogenerator is higher, indicating that the influence of the mass fraction of magnetic powder on the size of magnetized microcilia will further act on the output electrical performance of the TENG. The larger the size of the whisker-like magnetized microcilia and the higher the height. However, if the mass fraction of magnetic powder is further increased to 70%, the voltage will be unstable, the magnetic film will rupture after being tapped for a short time, and the voltage will decrease.

[0066] In summary, the present invention provides a negative electrode structure of a triboelectric nanogenerator, a preparation method thereof and an application. The preparation method includes: mixing a PDMS prepolymer, a curing agent and ZnS:Cu particles to form a first PDMS solution, and placing it in a first mold, and drying to obtain a light-emitting film; mixing a PDMS prepolymer, a curing agent and magnetic powder to form a second PDMS solution, laying the light-emitting film flat in a second mold, then placing the second PDMS solution in the second mold, performing a drying treatment after magnetization, and setting a magnetic field in a predetermined direction during the drying treatment, so that the magnetic powder grows upward to form a whisker-like magnetized microcilia array, and a negative electrode structure of a triboelectric nanogenerator is obtained. In the above manner, the present invention can prepare a PDMS film that can emit light during pressing and stretching and has a whisker-like magnetized microcilia array on its surface by a simple method and at a low cost, so that it can be used as a negative electrode structure in a triboelectric nanogenerator, effectively improving its output electrical performance.

[0067] 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 the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A preparation method of a negative electrode structure of a triboelectric nanogenerator, characterized in that, It includes the following steps: S1. Mix the PDMS prepolymer, curing agent and ZnS:Cu particles evenly according to a predetermined mass ratio to obtain the first PDMS solution; S2. Place the first PDMS solution in the first mold, and obtain a light-emitting film after drying; S3. Mix the PDMS prepolymer, curing agent and magnetic powder evenly according to a predetermined mass ratio to obtain the second PDMS solution; S4. Lay the light-emitting film flat in the second mold, then place the second PDMS solution in the second mold, perform a drying treatment after magnetization, and set a magnetic field in a predetermined direction during the drying treatment so that the magnetic powder grows upward to form a whisker-shaped magnetized microfibril array, thereby obtaining a triboelectric nanogenerator negative electrode structure.

2. The preparation method of the negative electrode structure of the triboelectric nanogenerator according to claim 1, wherein: In step S1, in the first PDMS solution, the mass ratio of the PDMS prepolymer to the curing agent is 10:1, and the mass ratio of the PDMS prepolymer to the ZnS:Cu particles is 1:9 to 8:

2.

3. The preparation method of the negative electrode structure of the triboelectric nanogenerator according to claim 2, characterized in that: The mass ratio of the PDMS prepolymer to the ZnS:Cu particles is 3:7 to 7:

3.

4. The preparation method of the negative electrode structure of the triboelectric nanogenerator according to claim 1, characterized in that: In step S2, the average thickness of the light-emitting film is 0.12 to 0.36 mm.

5. The preparation method of the negative electrode structure of the triboelectric nanogenerator according to claim 1, characterized in that: In step S3, in the second PDMS solution, the mass ratio of the PDMS prepolymer to the curing agent is 10:1, and the mass fraction of the magnetic powder in the PDMS prepolymer is 40% to 70%.

6. The preparation method of the negative electrode structure of the triboelectric nanogenerator according to claim 1, wherein: In step S4, the bottom diameter of the whisker-shaped magnetized microfibril is 1.1 to 2.3 mm, and the height is 4.4 to 6.5 mm; the average distance between adjacent whisker-shaped magnetized microfibrils is 1.1 to 2.0 mm.

7. The preparation method of the negative electrode structure of the triboelectric nanogenerator according to claim 1, characterized in that: The dosage ratio of the first PDMS solution to the second PDMS solution is 1:

2.

8. The preparation method of the negative electrode structure of the triboelectric nanogenerator according to claim 1, characterized in that: The size of the second mold is larger than that of the first mold.

9. A negative electrode structure of a triboelectric nanogenerator, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 8.

10. Application of the negative electrode structure of the triboelectric nanogenerator according to claim 9, characterized in that: The triboelectric nanogenerator negative electrode structure is used for the preparation of a triboelectric nanogenerator.

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