Printing ink, electrode and micro-supercapacitor and preparation method and application thereof

Abstract

This invention belongs to the field of electronic device technology, specifically relating to a printing ink, electrodes, and a micro supercapacitor, as well as their preparation method and applications. This invention directly uses a physical mixture of transition metal sulfides and graphene as the printing ink. Under specific conditions, triboelectric additive printing can yield high-precision printed electrode materials. The preparation method provided by this invention has advantages such as high processing accuracy, no need for templates or additives, and high ink utilization, and can be adapted to various flexible substrates. The electrodes prepared according to the preparation method provided by this invention can be used to prepare micro supercapacitors, and the prepared micro supercapacitors exhibit excellent energy storage performance.

Description

Technical Field

[0001] This invention belongs to the field of electronic device technology, specifically relating to a printing ink, an electrode, and a micro supercapacitor, as well as their preparation methods and applications. Background Technology

[0002] With the rapid development of microelectronics technology, electronic devices are constantly evolving towards portability, wearability, foldability, and miniaturization, creating a more urgent demand for high-performance flexible micro energy storage devices. Micro supercapacitors, as an emerging and important electrochemical energy storage device, typically have their positive and negative electrodes arranged alternately in an interdigitated geometry on the same plane. They eliminate the need for traditional separator materials, achieving electrode isolation through spatial separation, thereby effectively shortening the charge transport path between the positive and negative electrodes and reducing internal resistance. Therefore, micro supercapacitors have significant advantages in power density, rate performance, cycle life, and frequency response, and can be integrated into microelectronic systems as modular energy storage devices, showing broad application prospects in micro / nano devices, portable electronic devices, wearable devices, and implantable devices.

[0003] However, existing methods for fabricating electrodes for flexible micro supercapacitors have several shortcomings. On the one hand, traditional micro-nano fabrication methods, such as photolithography, etching, and vacuum deposition, are complex, highly dependent on equipment, and costly, making them unsuitable for large-area, low-cost fabrication of flexible substrates. On the other hand, solution-based fabrication techniques such as inkjet printing and screen printing typically require the introduction of binders, surfactants, or organic solvents, increasing process complexity and potentially introducing electrochemically inert components into the electrodes, thus affecting their conductivity and electrochemical performance. Therefore, existing fabrication methods still fall short of meeting the practical application requirements of flexible micro supercapacitors in terms of process simplification, material versatility, composition tunability, and cost control. Based on these issues, developing a novel micro-nano manufacturing technology that is simple, efficient, economical, and possesses high precision has become crucial for realizing the large-scale production and industrial application of flexible microelectronic devices. Summary of the Invention

[0004] In view of this, the present invention provides a printing ink, an electrode, and a micro supercapacitor, as well as their preparation method and application. The preparation method provided by the present invention can directly print to form electrodes with high precision and can be used to prepare micro supercapacitors. The preparation method provided by the present invention is simple, efficient, economical, and the electrodes prepared have high precision.

[0005] To address the aforementioned technical problems, the present invention provides a printing ink comprising a dispersing solvent and a transition metal sulfide and graphene dispersed in the dispersing solvent; The mass concentration of transition metal sulfides in the printing ink is 1-10%; The mass concentration of graphene in the printing ink is 1-10%.

[0006] Preferably, the transition metal sulfide includes MoS2 and / or WS2; The dispersion solvent includes one or more of N-methylpyrrolidone, divalent esters, and deionized water.

[0007] The present invention also provides a method for preparing an electrode, comprising the following steps: Electrodes are obtained by performing triboelectric additive printing on the substrate surface; the ink used for triboelectric additive printing is the printing ink described in the above technical solution. The friction-driven additive printing head applies a load of 0.01~0.2N to the substrate.

[0008] Preferably, the diameter of the printhead ball for friction-driven additive printing is 0.2~1mm, and the sliding speed of the printhead is 500~10000μm / s; The sliding cycle of the friction-driven additive printing is 50 to 2000 times.

[0009] Preferably, the substrate includes a flexible substrate, which includes a polyethylene terephthalate substrate, a polyimide substrate, or a polydimethylsiloxane substrate; The electrodes may be in the form of interdigitated electrodes.

[0010] The present invention also provides an electrode, which is prepared according to the preparation method described in the above technical solution.

[0011] This invention also provides the application of the electrodes described in the above technical solution in the fabrication of micro supercapacitors.

[0012] This invention also provides a method for fabricating a miniature supercapacitor, comprising the following steps: A microelectrode is obtained by friction-driven additive printing on the substrate surface; the ink used for friction-driven additive printing is the printing ink described in the above technical solution; the load applied to the substrate by the print head of the friction-driven additive printing is 0.01~0.2N; An electrolyte is coated onto the surface of the microelectrode to obtain a micro supercapacitor.

[0013] Preferably, the electrolyte includes 1-ethyl-3-methylimidazolium tetrafluoroborate electrolyte, potassium hydroxide solution, or PVA-H2SO4 electrolyte.

[0014] The present invention also provides a micro supercapacitor prepared according to the preparation method described above.

[0015] This invention directly uses a physical mixture of transition metal sulfides and graphene as printing ink. Under specific conditions, triboelectric additive printing can yield high-precision printed electrode materials. The preparation method provided by this invention has advantages such as high processing accuracy, no need for templates or additives, and high ink utilization, and it can be adapted to various flexible substrates. The electrodes prepared according to the method provided by this invention can be used to fabricate micro supercapacitors, and the fabricated micro supercapacitors exhibit excellent energy storage performance. Attached Figure Description

[0016] Figure 1 An optical microscope image of the interdigitated electrode prepared in Example 1; Figure 2 An optical microscope image of the linear electrode prepared in Comparative Example 1; Figure 3 The image shows the Raman test results of the interdigitated electrode prepared in Example 4; Figure 4 The figure shows the XPS test results of the interdigitated electrode prepared in Example 4; Figure 5 SEM images and EDS results of linear micro / nano structures obtained by printing with the printing inks in Examples 1-3; Figure 6 The cyclic voltammetry curve of the flexible micro supercapacitor in Example 1; Figure 7 The cyclic voltammetry curve of the flexible micro supercapacitor in Example 2; Figure 8 The cyclic voltammetry curve of the flexible micro supercapacitor in Example 3; Figure 9 The cyclic voltammetry curve of the flexible micro supercapacitor in Example 4; Figure 10 The cyclic voltammetry curves are for the flexible micro supercapacitor of Example 5. Detailed Implementation

[0017] The present invention provides a printing ink comprising a dispersing solvent and a transition metal sulfide and graphene dispersed in the dispersing solvent.

[0018] In this invention, the transition metal sulfide may include MoS2 and / or WS2, specifically MoS2 or WS2; the transition metal sulfide may be particulates, and the average particle size may be 1~50 μm, specifically 5 μm, 10 μm, 20 μm, 30 μm or 40 μm; the mass concentration of the transition metal sulfide in the printing ink is 1~10%, specifically 3%, 5% or 8%. In this invention, the graphene may have a size of 10~50 μm, specifically 20 μm, 30 μm or 40 μm; the mass concentration of graphene in the printing ink is 1~10%, specifically 2.5%, 5% or 7%. In this invention, the total mass concentration of the transition metal sulfide and graphene in the printing ink may be 2~20%, specifically 7.5%, 10% or 15%.

[0019] The present invention can regulate the electrochemical performance of the electrode by adjusting the mass concentration of transition metal sulfides and graphene in the printing ink.

[0020] In this invention, the dispersion solvent may include one or more of N-methylpyrrolidone (NMP), divalent ester (DBE), and deionized water (DI), specifically N-methylpyrrolidone, divalent ester, or deionized water.

[0021] In this invention, the preparation method of the printing ink may include the following steps: dispersing transition metal sulfides and graphene in a dispersion solvent to obtain the printing ink; the dispersion may include sequential stirring and ultrasonic treatment. This invention does not have special requirements for the stirring and ultrasonic conditions, as long as uniform dispersion is achieved.

[0022] The present invention also provides a method for preparing an electrode, comprising the following steps: Electrodes are obtained by friction-driven additive printing on the substrate surface; the ink used for friction-driven additive printing is the printing ink described in the above technical solution.

[0023] In this invention, the printhead of the friction-driven additive printing applies a load of 0.01~0.2N to the substrate, specifically 0.03N, 0.05N, 0.1N or 0.15N.

[0024] In this invention, the substrate may include a flexible substrate, which may be a polyethylene terephthalate (PET) substrate, a polyimide (PI) substrate, or a polydimethylsiloxane (PDMS) substrate. Different flexible substrates have different mechanical properties, and different substrates can be selected to suit different application scenarios.

[0025] In this invention, the diameter of the printhead ball for friction-driven additive printing can be 0.2~1mm, specifically 0.3mm, 0.5mm, or 0.8mm; the sliding speed of the printhead can be 500~10000μm / s, specifically 1000μm / s, 200μm / s, 5000μm / s, or 7000μm / s; and the sliding cycle of friction-driven additive printing can be 50~2000 times, specifically 100 times, 200 times, 400 times, 1000 times, or 1500 times. This invention achieves controllable deposition of molybdenum disulfide and graphene dispersion as printing ink on the substrate surface by adjusting process parameters such as the applied load (the load applied by the printhead to the substrate), sliding speed, and sliding cycle, thereby constructing electrodes with specific patterns and micro / nano structures. This invention allows for the control of the printed micro / nano structure size through the combined effects of ball diameter, print head speed, and sliding cycle, thereby influencing the electrochemical performance of the electrodes and ultimately regulating the electrochemical energy storage performance of the micro supercapacitor.

[0026] The present invention does not impose any special limitation on the shape of the electrode, which can be set according to actual needs; in the embodiments of the present invention, the electrode is in the form of an interdigitated electrode.

[0027] This invention also provides an electrode, which is prepared according to the preparation method described above. The electrode provided by this invention has high precision, can be miniaturized and integrated, and can be used to prepare micro supercapacitors.

[0028] This invention also provides the application of the electrodes described in the above technical solution in the fabrication of micro supercapacitors.

[0029] This invention also provides a method for fabricating a miniature supercapacitor, comprising the following steps: A microelectrode is obtained by friction-driven additive printing on the substrate surface; the ink used for friction-driven additive printing is the printing ink described in the above technical solution; the load applied to the substrate by the print head of the friction-driven additive printing is 0.01~0.2N; An electrolyte is coated onto the surface of the microelectrode to obtain a micro supercapacitor.

[0030] This invention utilizes friction-driven additive printing on a substrate surface to obtain microelectrodes. In this invention, the substrate may include a flexible substrate, which may be a polyethylene terephthalate (PET) substrate, a polyimide (PI) substrate, or a polydimethylsiloxane (PDMS) substrate.

[0031] In this invention, the load applied to the substrate by the printhead in the friction-driven additive printing is 0.01~0.2N, specifically 0.03N, 0.05N, 0.1N, or 0.15N. In this invention, the diameter of the ball bearing in the printhead for friction-driven additive printing can be 0.2~1mm, specifically 0.5mm or 0.8mm; the sliding speed of the printhead can be 500~10000μm / s, specifically 1000μm / s, 200μm / s, 5000μm / s, or 7000μm / s; the sliding cycle of the friction-driven additive printing can be 50~2000 times, specifically 100 times, 200 times, 400 times, 1000 times, or 1500 times. In this invention, the printhead performs reciprocating friction printing according to the target program to obtain stable, high-quality micro / nano structures; the reasonable limitation of the sliding cycle is a key factor affecting the stability of micro / nano structure forming.

[0032] In this invention, the microelectrode can be an interdigitated electrode, the length of which can be 400~600μm, specifically 450μm, 500μm or 550μm; the electrode spacing of which can be 50~300μm, specifically 70μm, 100μm, 150μm or 200μm.

[0033] After obtaining the microelectrode, the present invention coats the surface of the microelectrode with an electrolyte to obtain a micro supercapacitor. Before coating with the electrolyte, the present invention may also pre-treat the microelectrode, which may include rinsing the microelectrode with ethanol followed by wiping; the wiping may be done with a non-woven fabric.

[0034] In this invention, the electrolyte may include 1-ethyl-3-methylimidazolium tetrafluoroborate electrolyte, potassium hydroxide solution, or PVA-H2SO4 electrolyte; the molar concentration of the potassium hydroxide solution may be 5~7 mol / L, specifically 6 mol / L.

[0035] The present invention has no special requirements for the coating; conventional methods in the art can be used.

[0036] The method for fabricating a micro supercapacitor provided by this invention has advantages such as simplified process flow, strong material adaptability, and low cost, while ensuring structural designability.

[0037] This invention also provides a micro supercapacitor prepared according to the preparation method described above. The micro supercapacitor provided by this invention has excellent energy storage performance.

[0038] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0039] Example 1 MoS2 particles with a particle size of 1~10μm, graphene with a size of 10~50μm and N-methylpyrrolidone were dispersed uniformly under stirring and ultrasonic conditions to obtain printing ink; the mass concentration of MoS2 in the printing ink was 5% and the mass concentration of graphene was 2.5%.

[0040] A triboelectric printhead and a PET film were mounted on a triboelectric printing device. Printing ink was added to the contact area between the triboelectric printhead and the PET substrate. The diameter of the printhead ball was 0.5 mm, the loading force of the printhead (the load applied by the printhead to the PET substrate) was set to 0.03 N, the sliding speed was 2000 μm / s, and the sliding cycle was 400 times. Triboelectric additive printing was performed on the surface of the flexible PET substrate to obtain interdigitated electrodes with a length of 500 μm and an electrode spacing of 100 μm. The prepared interdigitated electrodes were rinsed with ethanol and then wiped with a non-woven cloth. After wiping, H2SO4-PVA electrolyte was coated on the surface of the interdigitated electrodes to obtain a flexible micro supercapacitor.

[0041] Examples 2-5 Flexible micro supercapacitors were prepared according to the method of Example 1, with the differences shown in Table 1.

[0042] Table 1. Conditions and parameters for preparing flexible micro supercapacitors in Examples 1-5

[0043] Comparative Example 1 Linear electrodes were prepared according to the conditions of Example 3, except that a load of 0.25 N was applied, resulting in a discontinuous and non-dense micro / nano structure.

[0044] Figure 1 An optical microscope image of the interdigitated electrode prepared in Example 1; from Figure 1 As can be seen from the preparation method provided by the present invention, continuous and dense electrodes can be printed.

[0045] Figure 2 The image shows an optical microscope image of the linear electrode prepared in Comparative Example 1. The optical microscope image reveals exposed substrate at the micro / nano structure. Due to the discontinuity of the electrode, circuit breaks occur during testing, preventing successful electrochemical measurements. This indicates that excessively high loads can affect the performance of the printed electrode.

[0046] The interdigitated electrode prepared in Example 4 was subjected to Raman spectroscopy and XPS testing, and the results are as follows: Figures 3-4 As shown, where Figure 3 The image shows the results of the Raman test. Figure 4The image shows the XPS test results.

[0047] Depend on Figure 3 Characteristic Raman peaks corresponding to both graphene and MoS2 can be observed in the interdigitated electrodes, indicating that graphene and MoS2 can coexist in the micro-nano structure formed by triboprinting through direct physical mixing of graphene and MoS2 powders, thereby realizing the construction of composite structures.

[0048] Depend on Figure 4 It can be seen that characteristic peaks corresponding to graphene and MoS2 were detected simultaneously in the interdigitated electrode, further proving that graphene and MoS2 can be successfully introduced and retained in the formed micro-nano structure electrode by directly physical mixing graphene and MoS2 powders.

[0049] Printing inks were prepared according to the methods of Examples 1-3. Three types of printing inks were used to print linear micro / nano structures according to the method of Example 1. The different printing conditions are as follows: the diameter of the ball bearing of the friction print head is 0.5 mm, the loading force of the print head is set to 0.03 N, the sliding speed is 2000 μm / s, the sliding cycle is 400 times, and a linear micro / nano structure with a length of 1000 μm is prepared on the surface of the flexible substrate.

[0050] The prepared linear micro / nano structures were examined using scanning electron microscopy (SEM) to obtain SEM images and EDS results, as shown below. Figure 5 As shown, SEM images reveal the morphology of the linear micro / nanostructure, while EDS elemental analysis results indicate the simultaneous presence of Mo, S, and C elements within the corresponding micro / nanostructure regions, further verifying the composite distribution of graphene and MoS2 in the micro / nanostructure through direct physical mixing of powders.

[0051] At 0.02 mA / cm 2 0.03mA / cm 2 0.05mA / cm 2 0.07mA / cm 2 and 0.1 mA / cm 2 Cyclic voltammetry tests were performed on the flexible micro supercapacitors prepared in Examples 1-5 at different current densities, and the resulting cyclic voltammetry curves are shown below. Figures 6-10 As shown, where Figure 6 The cyclic voltammetry curves for Example 1 are shown below. Figure 7 The cyclic voltammetry curves for Example 2 are shown below. Figure 8 The cyclic voltammetry curves for Example 3 are shown below. Figure 9 The cyclic voltammetry curves for Example 4 are shown below. Figure 10 The cyclic voltammetry curves are from Example 5.

[0052] The areal capacitance of the flexible micro supercapacitors prepared in Examples 1-5 under different current densities was obtained based on the cyclic voltammetry curves, and the results are shown in Table 2.

[0053] Table 2. Area capacitance of flexible micro supercapacitors in Examples 1-5 at different current densities.

[0054] As can be seen from the test results in Table 2, the micro supercapacitor provided by this invention has excellent energy storage performance.

[0055] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A printing ink, characterized in that, Includes a dispersing solvent and transition metal sulfides and graphene dispersed in the dispersing solvent; The mass concentration of transition metal sulfides in the printing ink is 1-10%; The mass concentration of graphene in the printing ink is 1-10%.

2. The printing ink according to claim 1, characterized in that, The transition metal sulfides include MoS2 and / or WS2; The dispersion solvent includes one or more of N-methylpyrrolidone, divalent esters, and deionized water.

3. A method for preparing an electrode, characterized in that, Includes the following steps: Electrodes are obtained by friction-driven additive printing on the substrate surface; The friction-driven additive printing ink is the printing ink described in claim 1 or 2; The friction-driven additive printing head applies a load of 0.01~0.2N to the substrate.

4. The preparation method according to claim 3, characterized in that, The diameter of the ball bearing in the friction-driven additive printing printhead is 0.2~1mm, and the sliding speed of the printhead is 500~10000μm / s; The sliding cycle of the friction-driven additive printing is 50 to 2000 times.

5. The preparation method according to claim 3, characterized in that, The substrate includes a flexible substrate, which includes a polyethylene terephthalate substrate, a polyimide substrate, or a polydimethylsiloxane substrate; The electrodes may be in the form of interdigitated electrodes.

6. An electrode, characterized in that, The electrode is prepared according to the preparation method described in any one of claims 3 to 6.

7. The application of the electrode according to claim 6 in the fabrication of a micro supercapacitor.

8. A method for fabricating a micro supercapacitor, characterized in that, Includes the following steps: A microelectrode is obtained by friction-driven additive printing on the substrate surface; the ink used for friction-driven additive printing is the printing ink described in claim 1 or 2. The friction-driven additive printing head applies a load of 0.01~0.2N to the substrate; An electrolyte is coated onto the surface of the microelectrode to obtain a micro supercapacitor.

9. The preparation method according to claim 8, characterized in that, The electrolyte includes 1-ethyl-3-methylimidazolium tetrafluoroborate electrolyte, potassium hydroxide solution, or PVA-H2SO4 electrolyte.

10. A miniature supercapacitor prepared according to the preparation method of claim 8 or 9.

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