Three-dimensional self-coiled micro-supercapacitor and controllable preparation method thereof

Abstract

The application belongs to the technical field of three-dimensional micro-nano manufacturing and energy storage, and discloses a three-dimensional self-coiled micro super capacitor and a controllable preparation method thereof, which comprises the following steps: preparing a double-layer film substrate, wherein the double-layer film substrate comprises a top layer of a conductive functional layer with a negative thermal expansion coefficient and a bottom layer of a magnetic film substrate with a positive thermal expansion coefficient, and the magnetic film substrate is uniformly distributed with high remanence material and magnetic heat material; preparing a patterned interdigital electrode on the surface of the conductive functional layer; preparing a positive electrode on one side of the interdigital electrode and a negative electrode on the other side of the interdigital electrode on the surface of the conductive functional layer to obtain a composite type planar micro super capacitor; bending the composite type planar micro super capacitor in a magnetic field to obtain a self-coiled structure; and adding a liquid crystal state electrolyte into the self-coiled structure to obtain a three-dimensional self-coiled micro super capacitor. The application further reduces the projection area of the device, improves the space utilization of the device, and further improves the energy density per unit area of the device.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of three-dimensional micro-nano manufacturing and energy storage, and particularly relates to a three-dimensional self-curling micro-supercapacitor and a controllable preparation method thereof. BACKGROUND

[0002] Compared with lithium ion batteries, the interdigital micro-supercapacitor benefits from a physically isolated electrode structure, does not need to introduce a diaphragm, and will not cause obvious abnormal safety accidents in a collision or high-temperature environment, and thus has the characteristics of high safety, high power density, long service life, environmental friendliness and easy integration. However, the interdigital micro-supercapacitor urgently needs to break through the technical bottleneck of low energy density. SUMMARY

[0003] To solve the problems in the prior art, the purpose of the present application is to provide a three-dimensional self-curling micro-supercapacitor and a controllable preparation method thereof. The present application further reduces the projection area of the device, improves the space utilization of the device, and thus improves the energy density per unit area of the device.

[0004] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0005] A controllable preparation method of a three-dimensional self-curling micro-supercapacitor, comprising the following processes:

[0006] Preparation of a double-layer thin film substrate, the double-layer thin film substrate comprising a top layer of a conductive functional layer with a negative thermal expansion coefficient and a bottom layer of a magnetic thin film substrate with a positive thermal expansion coefficient, the conductive functional layer being arranged on the surface of the magnetic thin film substrate, and the magnetic thin film substrate uniformly distributing high remanence materials and magnetic heat materials;

[0007] Preparation of a patterned interdigital electrode on the surface of the conductive functional layer;

[0008] Preparation of a positive electrode on one side of the interdigital electrode and a negative electrode on the other side of the interdigital electrode on the surface of the conductive functional layer to obtain a composite type planar micro-supercapacitor;

[0009] Bending deformation of the composite type planar micro-supercapacitor in a magnetic field to obtain a self-curling structure;

[0010] Addition of a liquid crystal state electrolyte to the self-curling structure to obtain the three-dimensional self-curling micro-supercapacitor.

[0011] Preferably, the conductive functional layer adopts a graphene thin film, a carbon nanotube film or a graphene and carbon nanotube mixture thin film.

[0012] Preferably, the patterned interdigital electrode is prepared on the surface of the conductive functional layer by laser processing.

[0013] Preferably, the magnetic thin film substrate is made of a polydimethylsiloxane film doped with the high remanence material and the magnetocaloric material.

[0014] Preferably, the high remanence material is made of neodymium iron boron particles, and the magnetocaloric material is made of magnetite particles.

[0015] Preferably, the preparation process of the magnetic thin film substrate comprises the following steps:

[0016] The neodymium iron boron particles, the magnetite particles and a polydimethylsiloxane solution are mixed to obtain a magnetic solution, a curing agent is added to the magnetic solution, the magnetic solution is uniformly spin-coated on the surface of a silicon wafer by spin coating, and then solidified and formed to obtain the magnetic thin film substrate.

[0017] Preferably, the mixing ratio of the neodymium iron boron particles, the magnetite particles and the polydimethylsiloxane solution is (5-50) g:(5-50) g:100 ml.

[0018] The curing agent is hydrogen-containing silicone oil, and 1-10 ml of hydrogen-containing silicone oil is added to the magnetic solution.

[0019] Preferably, the positive electrode and the negative electrode are prepared by an electrochemical deposition method.

[0020] Preferably, when the composite planar micro-supercapacitor is bent and deformed in a magnetic field:

[0021] The winding direction, speed, number of turns and configuration of the composite planar micro-supercapacitor are controlled by adjusting the process parameters of the electro-magnetic field process.

[0022] The process parameters of the electro-magnetic field process include the frequency, amplitude and direction of the alternating current, the structure, number of turns, material and winding method of the coil.

[0023] Preferably, the liquid crystal state electrolyte is an electrolyte obtained by mixing liquid crystal state lauryl ether and phosphoric acid in a mass ratio of 1:(5-20), and the liquid crystal state electrolyte is placed in the self-winding structure by drop coating.

[0024] The application also provides a three-dimensional self-winding micro-supercapacitor, which is prepared by the controllable preparation method of the three-dimensional self-winding micro-supercapacitor.

[0025] Compared with the prior art, the application has at least the following beneficial technical effects:

[0026] In the controllable preparation method of the three-dimensional self-coiled micro supercapacitor, the self-coiling method used does not need to introduce a sacrificial layer and a selective etching process, simplifies the preparation process flow, improves the operation safety, and saves the reaction time. In addition, unlike the existing magnetic driving mode, the high remanence material and the magnetic heat material are uniformly distributed in the conductive functional layer in the application, so that the application introduces a driving force through the high-frequency electro-magnetic heat effect, and realizes the further driving and accurate control of the coiling deformation based on the flexible regulation of the size and direction of the low-frequency electro-magnetic force, which is expected to solve the problems of insufficient driving force and poor controllability in the prior art, and improve the process repeatability and stability. Compared with the commonly used liquid aqueous electrolyte and solid / quasi-solid gel electrolyte, the application adopts a liquid crystal electrolyte. The liquid crystal electrolyte retains good fluidity and continuity while still maintaining a relatively ordered mesoporous structure, providing favorable diffusion power and transport channels for electrolyte ions, effectively alleviating the problems of high freezing point of liquid aqueous electrolyte and slow ion diffusion of solid / quasi-solid electrolyte, and being more conducive to improving the electrochemical energy storage performance of the energy storage device. As can be seen from the above scheme, the application further reduces the projection area of the device, improves the space utilization of the device, and further improves the energy density per unit area of the device. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 A three-dimensional self-coiled micro supercapacitor controllable preparation process schematic diagram provided in the embodiments of the application is provided.

[0028] Figure 2 A three-dimensional self-coiled micro supercapacitor processing flow schematic diagram provided in the embodiments of the application is provided.

[0029] In the figure: 1 - functional layer negative thermal expansion coefficient material, 2 - bottom layer positive thermal expansion coefficient material, 3 - high remanence material, 4 - magnetic heat material, 5 - high-frequency electromagnetic heat stress, 6 - low-frequency electromagnetic force, 7 - different characteristic size self-coiling configuration, 8 - laser, 9 - interdigital electrode, 10 - positive electrode, 11 - negative electrode, 12 - planar micro supercapacitor, 13 - three-dimensional self-coiled micro supercapacitor, 14 - liquid crystal electrolyte. DETAILED DESCRIPTION

[0030] In the following, specific embodiments of the present application will be described in detail with reference to the accompanying drawings, and according to these detailed descriptions, those skilled in the art can clearly understand the present application and can implement the present application. The features in each different embodiment can be combined to obtain new implementation modes, or replace some features in some embodiments to obtain other preferred implementation modes, without departing from the principles of the present application.

[0031] The present application aims at the problem of low energy density of micro supercapacitors, and proposes a high-efficiency three-dimensional strategy for the overall structure of the device, namely a novel dual-mode electromagnetic driving-regulating integrated strong driving, high-precision and regulatable self-curling technology, studies the controllable preparation mechanism of the three-dimensional self-curling micro supercapacitor, solves the problems of poor energy density improvement effect caused by the limited increase range of the electrode height, and poor device stability caused by cracks and collapse of the electrode, develops a three-dimensional self-curling micro supercapacitor with high space utilization and high energy density, and further widens the application scenarios.

[0032] Reference Figure 1 The controllable preparation method of the three-dimensional self-curling micro supercapacitor of the present application comprises the following processes:

[0033] A double-layer thin film substrate is prepared, as shown in Figure 1 The double-layer thin film substrate comprises a top layer of a conductive functional layer with a negative thermal expansion coefficient and a bottom layer of a magnetic thin film substrate with a positive thermal expansion coefficient, the conductive functional layer is arranged on the surface of the magnetic thin film substrate, and the magnetic thin film substrate is uniformly distributed with high remanence materials and magnetic heat materials; under the action of high-frequency "electrically generated magnetic heat" thermal stress and low-frequency "electrically generated magnetic force", the double-layer thin film substrate of the present application is driven and accurately regulated to occur self-curling deformation, so that the double-layer thin film substrate of the present application has a self-curling function;

[0034] A patterned interdigital electrode 9 is prepared on the surface of the conductive functional layer, and the interdigital electrode 9 also simultaneously serves as a current collector and a conductive electrode;

[0035] As shown in Figure 2 A positive electrode 10 is prepared on one side of the interdigital electrode 9 and a negative electrode 11 is prepared on the other side of the interdigital electrode 9 on the surface of the conductive functional layer, to obtain a composite type planar micro supercapacitor;

[0036] The composite type planar micro supercapacitor is subjected to bending deformation in a magnetic field to obtain a self-curling structure;

[0037] Liquid crystal state electrolyte 14 is added to the self-curling structure to obtain the three-dimensional self-curling micro supercapacitor of the present application.

[0038] In the above scheme of the present application, the conductive functional layer can adopt a graphene film, a carbon nanotube film or a graphene and carbon nanotube mixture film. For such a conductive functional layer, a patterned interdigital electrode 9 can be prepared on the surface of the conductive functional layer by using a laser processing method. Specifically, by controlling the processing power and scanning rate of laser processing, the above conductive functional layer can be induced to produce.

[0039] In the scheme, the magnetic thin film substrate can be a polydimethylsiloxane film doped with the high remanence material and the magnetocaloric material.

[0040] The preparation process of the magnetic thin film substrate includes:

[0041] The neodymium iron boron particles, the magnetite particles and the polydimethylsiloxane solution are mixed to obtain a magnetic solution, a curing agent is added to the magnetic solution, the magnetic solution is uniformly spin-coated on the surface of the silicon wafer by spin coating, and then is cured and formed to obtain the magnetic thin film substrate.

[0042] The curing agent is hydrogen-containing silicone oil, and 1-10 ml of the curing agent hydrogen-containing silicone oil is added to the magnetic solution.

[0043] Typically, the negative electrode 11 of the positive electrode 10 can be prepared by an electrochemical deposition method, and the negative electrode 11 of the positive electrode 10 can be a porous positive / negative electrode material with a high specific surface area, such as a transition metal oxide, a plated metal phosphide, and a conductive polymer.

[0044] In the scheme, when the composite planar micro-supercapacitor is bent and deformed in a magnetic field:

[0045] The winding direction, speed, number of turns and configuration of the composite planar micro-supercapacitor are controlled by adjusting the process parameters of the electro-magnetic field, and the electro-magnetic field is a double-mode high-low frequency electro-magnetic field generated by a three-dimensional Helmholtz coil.

[0046] The process parameters of the electro-magnetic field include the frequency, amplitude and direction of the alternating current, the structure, number of turns, material and winding method of the coil.

[0047] The above parameters are obtained by designing multiple experiments, and the final optimized parameters are obtained by continuously adjusting the parameters.

[0048] In the scheme, the liquid crystal electrolyte is an electrolyte obtained by mixing liquid crystal lauryl ether and phosphoric acid in a mass ratio of 1: (5-20), and the liquid crystal electrolyte is placed in the self-coiling structure by drop coating.

[0049] The principle of the technical scheme is as follows:

[0050] In order to realize the controllable preparation of the three-dimensional self-coiled micro super capacitor, the application adopts a novel dual-mode electromagnetic driving-regulating integrated strong driving, high precision and controllable self-coiling scheme, and the preparation of the double-layer magnetic film (i.e. double-layer film substrate) is the key. The double-layer magnetic film comprises the upper functional layer negative thermal expansion coefficient material 1 and the bottom positive thermal expansion coefficient material 2 to which high remanence material 3 and magnetic heat material 4 are added. In order to introduce thermal stress in the double-layer magnetic film, the application adopts electromagnetic heating mode. The magnetic heat material such as ferrite (Fe3O4) will generate high hysteresis loss under the action of high-frequency electric magnetic field, thereby causing temperature change, forming high-frequency electromagnetic thermal stress 5 in the double-layer magnetic film, and driving the double-layer magnetic film to bend and deform. At the same time, the bottom high remanence material neodymium iron boron (NdFeB) particles further drive and accurately regulate the coiling process under the action of low-frequency electric magnetic force. By regulating the process parameters (such as alternating current frequency / amplitude / direction, coil structure / turns / material / winding mode) of the electric magnetic field, the controllable preparation of the self-coiling structure 7 with different characteristic sizes is realized.

[0051] In order to prepare the interdigital electrode 9, the laser 8 is used to act on the surface of the functional layer negative thermal expansion coefficient material 1 to realize the in-situ preparation of the patterned electrode. In order to prepare the high-performance composite micro super capacitor, the electrode materials corresponding to the positive electrode 10 and the negative electrode 11 are further in-situ deposited on both sides of the interdigital electrode 9 by electrochemical deposition method to form the planar micro super capacitor 12. Under the driving of the foregoing self-coiling scheme, the preparation of the three-dimensional self-coiled micro super capacitor 13 is realized. Further, the liquid crystal state lauryl ether / phosphoric acid electrolyte 14 is dropped into the three-dimensional self-coiled micro super capacitor 13 by the drop coating method for subsequent electrochemical performance test.

[0052] Embodiment

[0053] The embodiment provides a typical controllable preparation method of the three-dimensional self-coiled micro super capacitor of the application, and specifically comprises the following steps.

[0054] Step 1, preparation of magnetic film precursor solution: neodymium iron boron particles (NdFeB), ferrite (Fe3O4) particles and PDMS solution are mixed and stirred uniformly according to the ratio of 8 g:8 g:20 ml, then 2 ml of curing agent hydrogen-containing silicone oil is added, and the above solution is uniformly spin-coated on the surface of a clean silicon wafer by spin coating, and then cured at 100 DEG C for two hours, thereby successfully preparing the magnetic film substrate. The thickness of the magnetic film substrate is 160 microns.

[0055] Step 2, a graphene solution with a concentration of 1 mg / ml is prepared and spin-coated on the surface of the magnetic film substrate obtained in step 1, followed by drying treatment, to form a conductive functional layer on the surface of the magnetic film substrate, thereby obtaining a double-layer film substrate, and the thickness of the double-layer film substrate is 180 microns;

[0056] Step 3, the double-layer film substrate in step 2 is peeled off from the surface of the silicon wafer and cut into a strip-shaped film, and a patterned interdigital electrode is manufactured on the surface of the strip-shaped film by laser processing, and the processing power (13.5 W), scanning speed (10 cm / s -1 ) are set, and the laser is applied to the surface of the top functional layer (i.e. the conductive functional layer) in step 2 to realize in-situ preparation of the patterned graphene interdigital electrode 9;

[0057] Step 4, a layer of polyaniline conductive polymer is deposited on the surface of the electrode on one side of the interdigital electrode 9 in step 3 by electrochemical deposition as a positive electrode material, and a layer of redox graphene is deposited on the electrode on the other side of the interdigital electrode 9 as a negative electrode material, to realize the preparation of a composite planar micro-supercapacitor;

[0058] Step 5, a three-dimensional uniform magnetic field coil is constructed, a controllable uniform magnetic field platform is built, and alternating current is input by using an alternating current / direct current source to in-situ control the strength and direction of the electrically generated magnetic field;

[0059] Step 6, the composite planar micro-supercapacitor obtained in step 4 is placed in the controllable uniform magnetic field (50 μT) in step 5, and the bottom magnetic film substrate magnetic heat material Fe3O4 particles will generate high hysteresis loss under the action of high-frequency electrically generated magnetic field, thereby causing temperature change, forming a thermal stress difference in the double-layer film substrate, and driving the film to bend and deform; at the same time, the bottom high remanence material NdFeB particles further drive and accurately control the curling process under the action of low-frequency electrically generated magnetic field, and finally a self-curling structure is obtained;

[0060] Step 7, lauryl ether and phosphoric acid are mixed in a mass ratio of 1:8 to prepare an electrolyte, and a liquid crystal state electrolyte is prepared, and a drop coating method is used to place the electrolyte in the self-curling structure obtained in step 6, to realize the controllable preparation of a three-dimensional self-curling composite micro-supercapacitor.

[0061] After detection, the main technical indicators of the three-dimensional self-curling micro-supercapacitor obtained in this embodiment are as follows:

[0062] Electrochemical energy storage performance: the projected area of the device is reduced by 3 times, the capacitance and energy density are increased by 3 times, the electrochemical impedance is ≤100 Ω, and the energy storage area capacitance is 12.9 mF cm -2 , and the area energy density is 14.7 μWh cm -2

[0063] The successful development of the above self-coiling manufacturing new method and the new low-temperature-resistant liquid crystal state electrolyte can provide an effective strategy for the development of micro supercapacitors with high space utilization and high energy density, further promote the performance improvement of micro energy storage devices, and have important significance for accelerating the national "carbon peak and carbon neutral" process.

[0064] The above is only one embodiment of the present application, not all or only one embodiment, any equivalent transformation of the technical scheme of the present application adopted by a person skilled in the art by reading the present application is covered by the claims of the present application.

Claims

1. A controllable preparation method of a three-dimensional self-rolling micro supercapacitor, characterized in that: The process includes the following: Prepare a double-layer thin film substrate, the double-layer thin film substrate comprising a top conductive functional layer with a negative thermal expansion coefficient and a bottom magnetic thin film substrate with a positive thermal expansion coefficient, the conductive functional layer being disposed on the surface of the magnetic thin film substrate, and the magnetic thin film substrate having a high remanence material and a magnetocaloric material uniformly distributed therein; A patterned interdigitated electrode (9) is prepared on the surface of the conductive functional layer; On the surface of the conductive functional layer, a positive electrode (10) is prepared on one side of the interdigital electrode (9), and a negative electrode (11) is prepared on the other side of the interdigital electrode (9), thereby obtaining a composite planar micro-supercapacitor; Bending and deforming the composite planar micro-supercapacitor in a magnetic field to obtain a self-curling structure; Adding a liquid crystal electrolyte to the self-curling structure to obtain the three-dimensional self-curling micro supercapacitor; The conductive functional layer is made of a graphene film, a carbon nanotube film or a graphene and carbon nanotube mixture film; The high remanence material is made of neodymium iron boron particles, and the magnetocaloric material is made of ferroferric oxide particles; The liquid crystal electrolyte is an electrolyte prepared by mixing liquid crystal lauryl ether and phosphoric acid in a mass ratio of 1:(5-20), and the liquid crystal electrolyte is placed in the self-curling structure by drop coating.

2. The controllable preparation method of a three-dimensional self-rolling micro supercapacitor according to claim 1, characterized in that: Patterned interdigitated electrodes (9) are prepared on the surface of the conductive functional layer by laser processing.

3. The controllable preparation method of a three-dimensional self-rolling micro supercapacitor according to claim 1, characterized in that: The magnetic film substrate is a polydimethylsiloxane film doped with the high remanence material and the magnetocaloric material.

4. The controllable preparation method of a three-dimensional self-rolling micro supercapacitor according to claim 1, characterized in that: The preparation process of the magnetic film substrate includes: Mixing NdFeB particles, Fe3O4 particles and polydimethylsiloxane solution to obtain a magnetic solution, adding a curing agent to the magnetic solution, and evenly coating the magnetic solution on the surface of a silicon wafer by spin coating, and then curing to obtain the magnetic film substrate; The mixing ratio of the NdFeB particles, Fe3O4 particles and polydimethylsiloxane solution is (5-50) g: (5-50) g: 100 ml; The curing agent is hydrogenated silicone oil, and 1-10 ml of hydrogenated silicone oil is added to the magnetic solution.

5. The controllable preparation method of a three-dimensional self-rolling micro supercapacitor according to claim 1, characterized in that: The positive electrode (10) and the negative electrode (11) are prepared by electrochemical deposition.

6. The controllable preparation method of a three-dimensional self-rolling micro supercapacitor according to claim 1, characterized in that: When the composite planar micro supercapacitor is bent and deformed in a magnetic field: By adjusting the process parameters of the electromagnetism process, the curling direction, speed, number of turns and configuration of the composite planar micro supercapacitor are controlled. The process parameters of the electromagnetism process include: the frequency, amplitude, and direction of the alternating current, and the structure, number of turns, material, and winding method of the coil.

7. A three-dimensional self-rolling micro supercapacitor, characterized in that: The three-dimensional self-rolling micro supercapacitor is prepared by the controllable preparation method of the three-dimensional self-rolling micro supercapacitor according to any one of claims 1 to 6.

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