Preparation method of flexible DAFC / strain sensor packaging integrated bionic composite device

Abstract

The invention discloses a preparation method of a flexible [mu] DAFC / strain sensor packaging integrated bionic composite device, and the method prepares an energy supply / sensing integrated composite electronic skin device which highly simulates the function and structure of human skin. The design of the packaging / polar plate / diffusion layer integrated muDAFC membrane electrode is innovatively developed; a super-wetting carbon aerogel material is adopted to carry out solid-state supply structure design of liquid alcohol fuel, micro regulation and control in the fuel supply process are achieved, and the reliability of the flexible mu DAFC is improved. On the other hand, in-situ preparation of a sensor sensitive array structure is innovatively and directly carried out in a muDAFC flexible packaging material, namely, two different microstructures of a micro fuel cell electrode and a sensor electrode are realized on a flexible substrate, and a high-performance strain / temperature sensor array can be realized without a packaging process; the self-powered electronic skin device with high integration level is realized.

Description

Technical Field

[0001] The present invention relates to a bionic composite device, in particular to a flexible bionic composite device which is integrated with a micro direct alcohol fuel cell (μDAFC) and a strain sensor package. Background Art

[0002] Electronic skin (e-skin) is a novel microsystem that mimics the sensory functions of human skin. Its high flexibility and adaptability make it an ideal interface between electronic devices and robotic bodies. However, one of the technical bottlenecks it faces is distributed in-situ energy harvesting and generation. Traditional rigid energy supply structures such as lithium-ion batteries and zinc-air batteries are not compatible with the ultra-thin and flexible structure of e-skin. In-situ power generation devices such as vibration energy harvesters and nano-friction generators have too low output performance to meet the energy needs of e-skin. Furthermore, as robots continue to shrink in size and the demand for control precision continues to increase, the functional units of e-skin need to achieve various functions such as sensing, data acquisition and transmission, and power supply within a very small size.

[0003] μDAFC offers advantages such as easy fuel replenishment and high energy density. It can not only meet the energy needs of electronic skin data acquisition / analysis, signal transmission, but also output power to power other robot components. If coupled with efficient and precise fuel supply and mass transfer management and a flexible packaging solution, it will be more suitable for the distributed in-situ energy generation needs of robotic electronic skin. Building on this foundation, the development of a structurally integrated composite device based on a flexible direct alcohol fuel cell and robotic tactile sensors (such as pressure, strain, vibration, temperature, and humidity) will further reduce device size and improve control precision. Laser-induced graphene (LIG) technology has been widely used in the design of flexible electronic devices. Its ability to pattern graphene on flexible polymer substrates makes it ideally suited for the design of flexible μDAFC packaging structures. In situ fabrication of three-dimensional porous graphene within the polymer can be used to construct self-encapsulated strain sensor sensitive structures. The characteristics of LIG technology offer a new approach for the integrated integration of flexible micro fuel cells and flexible strain sensors. Summary of the Invention

[0004] This invention addresses the need for distributed, high-performance in-situ energy supply technology and highly integrated structural and functional integration for robotic electronic skin. By simulating the structural characteristics of human skin and subcutaneous muscle for integrated energy supply and sensing, this invention provides a method for fabricating a flexible, micro-DAFC / strain sensor packaged and integrated biomimetic composite device. This invention conducts research on the design of a flexible, thin-film, all-solid-state micro-DAFC structure. Simultaneously, incorporating laser-induced graphene technology, the invention also investigates the design of a flexible strain sensor within the micro-DAFC package. This breakthrough in the integrated packaging and integration of micro-DAFC / strain sensor composite devices allows for the realization of an electronic skin device with integrated energy supply and sensing.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] A method for preparing a flexible μDAFC / strain sensor package integrated bionic composite device comprises the following steps:

[0007] Step 1, preparation of flexible sensing structure: (1) Using laser-induced graphene as the sensitive material of the strain sensor, adding a nanomaterial solution when preparing a graphene precursor polymer film to form a polymer-modified material composite layer, wherein the nanomaterial is one of other two-dimensional materials such as molybdenum disulfide, black phosphorus, MXene, etc.; (2) Using an optical device to regulate the incident laser so that the generated sensor electrode is inside the polymer, that is, forming a self-encapsulated sensor sensitive structure, the optical device needs to be transparent to the CO2 laser band and have a higher refractive index than the polymer, such as zinc selenide glass; (3) Using the negative temperature characteristics of laser-induced graphene to prepare an independent temperature sensor inside the device;

[0008] Step 2. Preparation of microstructure of high-reliability flexible μDAFC: (1) Design of integrated package / electrode plate / diffusion layer structure: Generate three-dimensional graphene electrode on polyimide film by CO2 laser irradiation using laser-induced graphene technology; Use carbon aerogels with different hydrophilic and hydrophobic properties as carriers to prepare Pt and PtRu nanocatalysts by microwave-assisted ethylene glycol method and nanocapsule method; Deposit microporous layer and catalytic layer on graphene electrode by spraying / brushing, and optimize the hydrophilic and hydrophobic properties of microporous layer and catalytic layer and microporous structure by microstructure and wetting properties of carbon glue. (2) hot pressing a three-dimensional graphene electrode loaded with an anode catalyst layer and a cathode catalyst layer and a proton exchange membrane into a sandwich structure to obtain a flexible μDAFC package / plate / membrane electrode integrated device; (3) performing solid-state storage of the alcohol solution and regulating the vaporization process: selecting an activated carbon material as an adsorption carrier for the alcohol solution, and designing a fuel supply structure using a flexible polymer as a packaging material to achieve flexible μDAFC on-demand regulation of the fuel supply structure, wherein the flexible polymer is one of PDMS (polydimethylsiloxane) and PET (polyethylene terephthalate);

[0009] Step 3. Preparation and packaging integration of flexible μDAFC / sensing structure and function integration: (1) Place the strain sensor on the outside of the flexible μDAFC cathode electrode, and place the temperature sensor on the anode side which is less affected by strain; (2) Use laser internal carbonization and conductive silver paste to achieve electrical connection in the flexible μDAFC / sensing structure and function integration device; (3) Use PDMS or ion polymer membrane solution casting and curing to prepare the fuel chamber of the μDAFC battery, use plasma to treat the connection between each component, and use laser ablation to etch through holes inside the device as mass transfer channels; (4) Use bonding, chemical grafting or hot pressing to carry out integrated packaging integration.

[0010] Compared with the prior art, the present invention has the following advantages:

[0011] This invention fabricates an integrated power supply / sensing composite electronic skin device that closely mimics the functions and structure of human skin. Laser-induced graphene technology is employed to innovatively design a micro-DAFC membrane electrode with an integrated package / electrode plate / diffusion layer. Furthermore, super-wettable carbon aerogels are employed to design a solid-state supply structure for liquid alcohol fuels, enabling microscopic control of the fuel supply process and improving the reliability of the flexible μDAFC. Furthermore, this invention innovatively fabricates a sensor array directly within the μDAFC flexible packaging material. This allows for the creation of two distinct microstructures, a micro fuel cell electrode and a sensor electrode, on a flexible substrate. This eliminates the need for packaging, resulting in a high-performance strain / temperature sensor array and a highly integrated, self-powered electronic skin device. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 Design schematic diagram for the temperature sensing unit of the composite device;

[0013] Figure 2 Schematic diagram of the flexible μDAFC / strain sensor integrated structure design;

[0014] Figure 3 Schematic diagram of the overall structure of the flexible μDAFC / strain sensor package integrated integrated bionic composite device. DETAILED DESCRIPTION

[0015] The technical solution of the present invention is further described below with reference to the accompanying drawings, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention that does not depart from the spirit and scope of the technical solution of the present invention should be included in the scope of protection of the present invention.

[0016] The present invention provides a method for preparing a flexible μDAFC / strain sensor package integrated integrated bionic composite device, the method comprising the following steps:

[0017] Step 1. Preparation of flexible sensing structure: (1) Graphene based on laser induction is used as the sensitive material of the strain sensor, and other two-dimensional materials such as molybdenum disulfide, black phosphorus, MXene, etc. are used to modify the graphene to improve the sensitivity of the strain sensor and expand its detection range; therefore, when preparing the graphene precursor polymer film, the corresponding material solution is added to form a polymer-modified material composite layer, and finally a double-layer polymer film is prepared; (2) Optical devices such as zinc selenide glass are used to control the incident laser so that the generated sensor electrode is inside the polymer, that is, a self-encapsulated sensor sensitive structure is formed; (3) The negative temperature characteristic of laser-induced graphene makes it a sensitive material for temperature sensors. In order to distinguish the influence of mechanical strain and device operating temperature on graphene resistance, that is, to achieve decoupling between strain signals and temperature signals, an independent temperature sensor is designed inside the device. The data collected by the temperature sensor is used for strain sensor data correction to improve the accuracy of the strain sensor.

[0018] Step 2: Preparation of microstructure of high-reliability flexible μDAFC: (1) First, design the integrated structure of package / plate / diffusion layer: Use laser-induced graphene technology to generate three-dimensional graphene electrodes on polyimide membranes by CO2 laser irradiation. During the process, the microstructure can be optimized by adjusting the thickness and characteristics of the PI membrane, laser processing process and other parameters to optimize the mass transfer process of alcohol water vapor, oxygen, carbon dioxide, etc. in the electrode; Use carbon aerogels with different hydrophilic and hydrophobic properties as carriers, and prepare Pt and PtRu nanocatalysts by microwave-assisted ethylene glycol method and nanocapsule method; Deposit microporous layer and catalytic layer on the graphene electrode by spraying / brush printing, and optimize the hydrophilic and hydrophobic properties of microporous layer and catalytic layer and microporous structure by microstructure and wetting properties of carbon glue. (2) The three-dimensional graphene electrode loaded with anode catalyst layer and cathode catalyst layer is hot pressed with proton exchange membrane in a sandwich structure to obtain a flexible μDAFC package / plate / membrane electrode integrated device. (3) Finally, the solid-state storage and vaporization process of the alcohol solution are regulated: activated carbon materials with polar functional groups that can regulate the relative volatility of the methanol solution are selected as the adsorption carrier of the alcohol solution, and flexible polymers such as PDMS (polydimethylsiloxane) and PET (polyethylene terephthalate) are used as packaging materials to design the fuel supply structure, so as to realize the flexible μDAFC to regulate the fuel supply structure on demand.

[0019] Step 3: Flexible μDAFC / sensor structure functional integration preparation and packaging integration: (1) The key to the design of the flexible μDAFC / sensor composite integrated structure is to simultaneously realize the design and production of the flexible sensor in the flexible μDAFC battery packaging structure. The LIG technology used in the present invention will greatly simplify the electrode preparation process, thereby realizing the integrated structure design. After the sensor is completed, the battery is manufactured on this basis. The strain sensor is placed on the outside of the flexible μDAFC cathode electrode, and the temperature sensor is placed on the anode side which is less affected by the strain. Figures 1 to 3 (2) The electrical connection in the flexible μDAFC / sensor structure and function integrated device is achieved by laser internal carbonization and conductive silver paste. (3) The fuel chamber of the μDAFC battery is cast and solidified using PDMS or ion polymer membrane solution. The connection points of each component are treated with plasma. Through holes are etched inside the device by laser to serve as mass transfer channels. After that, the integrated packaging is carried out by gluing, chemical grafting or hot pressing.

[0020] Example:

[0021] Step 1. Preparation of flexible sensing structure: (1) Using laser-induced graphene as the sensitive material of the strain sensor, when preparing the graphene precursor polymer film, add molybdenum disulfide solution to modify the graphene to form a polymer-modified material composite layer; (2) Using zinc selenide glass to regulate the incident laser, in addition to being transparent to the CO2 laser band, its refractive index is higher than that of the polymer, so that the generated sensor electrode is inside the polymer, that is, a self-encapsulated sensor sensitive structure is formed; (3) Using the negative temperature characteristics of laser-induced graphene to prepare an independent temperature sensor.

[0022] Step 2. Preparation of flexible μDAFC / sensing structure and function integration. Preparation of high reliability flexible μDAFC microstructure: The specific steps are as follows: (1) Generate three-dimensional graphene electrodes on polyimide membranes by CO2 laser irradiation; (2) Use carbon aerogels with different hydrophilic and hydrophobic properties as carriers to prepare Pt and PtRu nanocatalysts by microwave-assisted ethylene glycol method and nanocapsule method; (3) Deposit microporous layers and catalytic layers that can optimize the gas-liquid two-phase mass transfer structure on the graphene electrodes by spraying; (4) Place the three-dimensional graphene electrodes loaded with anode catalytic layers and cathode catalytic layers on the proton exchange membrane. Sandwich structure hot pressing; (5) In order to carry out solid-state storage of alcohol solution and control of vaporization process, phenolic resin is selected as the main precursor, and nitrogen-containing compounds are added at the same time. The following process flow is adopted to prepare carbon aerogel: first, the hydrogel precursor is prepared by hydrothermal method. In order to keep the microstructure in the colloid from collapsing, it is freeze-dried. Then, the obtained dry gel is subjected to high-temperature carbonization treatment under ammonia conditions at 800°C to obtain carbon aerogel; the prepared carbon aerogel is used as the adsorption carrier of the alcohol solution and PDMS is used as the packaging material, thereby realizing the flexible μDAFC on-demand fuel supply structure.

[0023] Step 3: Integrated device packaging and integration based on flexible μDAFC batteries: (1) To realize the flexible μDAFC / sensor composite integrated structure, the flexible battery is manufactured based on the completed sensor, wherein the strain sensor is located on the outside of the flexible μDAFC cathode electrode, and the temperature sensor is located on the anode side which is less affected by strain; (2) LIG technology is used to directly prepare LIG on the side of the membrane electrode to realize the electrical connection and packaging structure design of the flexible μDAFC battery; (3) PDMS casting and curing is used to prepare the fuel cavity of the μDAFC battery, and the connection points of each component are treated with plasma, and then the battery is integrated and packaged by gluing; (4) Through holes are formed inside the device by laser ablation as mass transfer channels.

Claims

1. A method for preparing a flexible μDAFC / strain sensor package integrated biomimetic composite device, characterized in that The method comprises the following steps: Step 1: Preparation of flexible sensing structure: (1) Using laser-induced graphene as the sensitive material of the strain sensor, adding a nanomaterial solution when preparing a graphene precursor polymer film to form a polymer-modified material composite layer; (2) Using an optical device to control the incident laser so that the generated sensor electrode is inside the polymer, that is, forming a self-encapsulated sensor sensitive structure; (3) Using the negative temperature characteristics of laser-induced graphene to prepare an independent temperature sensor inside the device; Step 2. Preparation of microstructure of high-reliability flexible μDAFC: (1) Design of package / plate / diffusion layer integrated structure: Generate three-dimensional graphene electrode on polyimide membrane by CO2 laser irradiation using laser-induced graphene technology; Use carbon aerogels with different hydrophilic and hydrophobic properties as carriers to prepare Pt and PtRu nanocatalysts by microwave-assisted ethylene glycol method and nanocapsule method; Deposit microporous layer and catalytic layer on graphene electrode by spraying / brush printing, and optimize the hydrophilic and hydrophobic properties of microporous layer and catalytic layer and microporous structure by microstructure and wetting properties of carbon glue; (2) Hot press the three-dimensional graphene electrode loaded with anode catalyst layer and cathode catalyst layer and proton exchange membrane into a sandwich structure to obtain flexible μDAFC package / plate / membrane electrode integrated device; (3) Solid-state storage of alcohol solution and regulation of vaporization process: Select activated carbon materials as adsorption carriers of alcohol solution and flexible polymers as packaging materials to design fuel supply structure, so as to realize flexible μDAFC to regulate fuel supply structure on demand; Step 3. Preparation and packaging integration of flexible μDAFC / sensing structure functions: (1) Place the strain sensor on the outside of the flexible μDAFC cathode electrode, and place the temperature sensor on the anode side which is less affected by strain; (2) Use laser internal carbonization and conductive silver paste to achieve electrical connection in the flexible μDAFC / sensing structure function integrated device; (3) Prepare the fuel chamber of the μDAFC battery, use plasma to treat the connection points of each component, and use laser ablation to etch through holes inside the device as mass transfer channels; (4) Perform integrated packaging integration.

2. The method for preparing the flexible μDAFC / strain sensor package integrated integrated bionic composite device according to claim 1, characterized in that In the step 1, the nanomaterial is one of molybdenum disulfide, black phosphorus, and MXene.

3. The method for preparing the flexible μDAFC / strain sensor package integrated integrated bionic composite device according to claim 1, characterized in that In the step 1, the optical device needs to be transparent to the CO2 laser wavelength band and have a higher refractive index than the polymer.

4. The method for preparing the flexible μDAFC / strain sensor package integrated integrated bionic composite device according to claim 3, characterized in that The optical device is zinc selenide glass.

5. The method for preparing the flexible μDAFC / strain sensor package integrated integrated bionic composite device according to claim 1, characterized in that In the step 2, the flexible high molecular polymer is one of PDMS and PET.

6. The method for preparing the flexible μDAFC / strain sensor package integrated integrated biomimetic composite device according to claim 1, characterized in that In the step three, the fuel chamber of the μDAFC battery is prepared by solution casting and curing of PDMS or ion polymer membrane.

7. The method for preparing the flexible μDAFC / strain sensor package integrated integrated bionic composite device according to claim 1, characterized in that In the step three, the integrated packaging is performed by gluing, chemical grafting or hot pressing.

8. A flexible μDAFC / strain sensor package integrated bionic composite device prepared by the method according to any one of claims 1 to 7.

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