Manufacturing method of laser-induced graphene supercapacitor

Abstract

The invention discloses a laser-induced graphene supercapacitor and a manufacturing method thereof, and aims to provide high-power-density energy storage equipment which can be directly formed on a flexible substrate. Laser is used for directly writing on the polyimide film, so that conversion from PI to porous graphene is realized, and an electrode with a high surface area is formed. The electrodes and a conductive copper strip are integrated on a stainless steel substrate to form a super capacitor layer. The manufacturing process includes inserting a microporous polypropylene separator immersed in a sodium sulfate solution between two electrodes to achieve ion exchange.

Description

Technical Field

[0001] The present invention relates to an integrated power supply packaging technology, in particular to a laser-induced graphene supercapacitor on a flexible substrate for packaging an integrated power supply and a related manufacturing method thereof. Background Art

[0002] As electronic devices move towards miniaturization and lightweight, especially in the fields of wearable medical and IoT devices, the demand for integrated power supplies is growing. Traditional energy storage devices, such as batteries and supercapacitors, perform well in certain applications, but they are usually not directly integrated into the device's packaging substrate, which limits the device's miniaturization and power transmission efficiency.

[0003] Therefore, it is particularly important to develop a new energy storage device and method that can be grown directly on a packaging substrate and has a high power density. Summary of the invention

[0004] The present invention provides a laser-induced graphene-based supercapacitor formed directly on a flexible substrate to achieve efficient power transmission and higher power density. The technology uses a CO2 laser to directly write on a polyimide (PI) film, converting PI into porous graphene to form high surface area electrodes. These electrodes are then integrated with copper tape on a stainless steel substrate to form a planar supercapacitor layer.

[0005] The present invention provides a method for manufacturing a laser-induced graphene supercapacitor on a flexible substrate for packaging an integrated power supply, the method comprising the following steps: a) Direct writing on polyimide film using CO2 laser to form porous graphene electrodes; b) integrating a conductive copper tape with the porous graphene electrode; c) A microporous polypropylene separator was inserted between the two electrodes, and the separator was soaked in 1 M sodium sulfate solution.

[0006] The operating parameters of the CO2 laser include a wavelength of 10-11 μm, 9-10% of the maximum power, and 4-5% of the maximum speed.

[0007] The supercapacitor obtained by the above method includes a porous graphene electrode formed by direct writing of a CO2 laser on a polyimide (PI) film, and a conductive copper tape integrated with the electrode.

[0008] The preparation process of the porous graphene electrode includes using a CO2 laser with a wavelength of 10.6 μm to scribble on a polyimide film to achieve the conversion of polyimide to porous graphene.

[0009] The pore size of the porous graphene electrode is about 4-5 microns.

[0010] The supercapacitor further includes a microporous polypropylene separator inserted between the two electrodes, and the separator is immersed in a 1M sodium sulfate (Na2SO4) solution to achieve ion exchange.

[0011] The technical solution of the present invention is described in more detail below.

[0012] 1) Preparation of graphene: A CO2 laser system (wavelength 10.6μm, maximum power 30W) is used to perform laser scribing on a polyimide (PI) film. By adjusting the laser power and scanning speed (optimized parameters are 9.5% of the maximum power and 4.5% of the maximum speed), the desired pattern is directly written on the PI film to achieve the conversion of PI to porous graphene. The local high temperature (>2500℃) generated in this process causes the CO, C=O and CN bonds in PI to break and quickly rearrange to form a graphite structure.

[0013] 2) Material characterization: Scanning electron microscopy (SEM), energy dispersive spectroscopy (SEM-EDS) and Fourier transform infrared spectroscopy (FTIR) were used to observe and analyze the morphology and chemical structure of laser-induced graphene (LIG). SEM analysis revealed the porous structure of LIG with a pore size of about 4 microns, while SEM-EDS and FTIR analysis confirmed that the material was mainly composed of carbon and oxygen, with functional groups such as hydroxyl, aromatic C═C stretching and CH bending, and the obtained material was mainly graphene oxide.

[0014] 3) Fabrication of supercapacitor: Two LIG electrodes were mounted on a glass slide via conductive copper tape and assembled face to face. A microporous polypropylene separator soaked in 1M sodium sulfate (Na2SO4) solution was inserted between the two electrodes to enable ion exchange. The supercapacitor was fabricated by welding wires at both ends as contact points for electrochemical characterization studies and sealing the entire device with polyimide tape.

[0015] Electrochemical Characterization: The supercapacitor was electrochemically characterized using a VMP-3 multi-channel potentiostat in a two-electrode configuration. Using 1 mol / L Na2SO4 solution as the electrolyte, the electrochemical performance and double-layer capacitance of the symmetrical cell were studied by time-domain cyclic voltammetry (CV), electrostatic charge-discharge (GCD), and frequency-domain electrochemical impedance spectroscopy (EIS). CV and GCD tests were performed in a voltage window of 0-0.8 V to evaluate the charge-discharge performance and capacitance density of the capacitor.

[0016] Electrochemical test results show that the LIG-based supercapacitor exhibits ideal electric double-layer capacitor (EDLC) performance with nearly rectangular CV curves and symmetrical linear GCD curves, indicating excellent reversibility and fast charge and discharge capabilities. The capacitance density is estimated to be 1.17 mF / cm at a scan rate of 50 mV / s. 2 Up to 1.2mF / cm 2 , showing comparable performance to existing technologies, but with a simpler and more economical manufacturing process. EIS analysis further confirmed the high conductivity and low charge transfer resistance of LIG supercapacitors, which are crucial for improving the performance of energy storage devices. Industrial Applicability

[0017] The present invention successfully prepared porous graphene electrodes on flexible polyimide films by laser induction technology, and developed a new type of supercapacitor based on this. This supercapacitor not only exhibits excellent electrochemical properties, including high capacitance density and low internal resistance, but also has a simple manufacturing process, low cost and environmental friendliness.

Claims

1. A method for manufacturing a laser-induced graphene supercapacitor on a flexible substrate for encapsulating an integrated power source, the method comprising the following steps: a) Direct writing on polyimide film using CO2 laser to form porous graphene electrodes; b) integrating a conductive copper tape with the porous graphene electrode; c) A microporous polypropylene separator was inserted between the two electrodes and the separator was immersed in a sodium sulfate solution.

2. The manufacturing method according to claim 1, characterized in that: The CO2 laser's operating parameters include a wavelength of 10-11 μm, 9-10% of maximum power, and 4-5% of maximum speed.

3. A supercapacitor obtained by any method of claims 1-2, characterized in that: The supercapacitor includes a porous graphene electrode formed by direct CO2 laser writing on a polyimide (PI) film, and a conductive copper tape integrated with the electrode.

4. The supercapacitor according to claim 3, characterized in that: The preparation process of the porous graphene electrode includes using a CO2 laser with a wavelength of 10.6 μm to scribble on a polyimide film to achieve the conversion of polyimide to porous graphene.

5. The supercapacitor according to claim 3 or 4, characterized in that: The pore size of the porous graphene electrode is about 4-5 microns.

6. The supercapacitor according to any one of claims 3 to 5, characterized in that: The supercapacitor further includes a microporous polypropylene separator inserted between the two electrodes, which is immersed in a 1M sodium sulfate (Na2S04) solution to achieve ion exchange.