A crack-controlled flexible stretchable electrode based on a two-dimensional material composite sandwich and its preparation method

Abstract

This invention discloses a fatigue-resistant flexible stretchable composite electrode with crack-regulating function and its preparation method, aiming to solve the problems of crack propagation, conductivity instability, and short fatigue life of metal thin film electrodes during cyclic stretching. The method includes: forming a first gold electrode layer on a flexible elastomer substrate; dispersing graphene and molybdenum disulfide in a solvent and depositing them on the surface of the first gold electrode layer to form a composite interlayer; and then forming a second gold electrode layer, with the composite interlayer sandwiched between the two gold electrode layers. During stretching, the composite interlayer regulates the initiation and propagation of cracks in the gold layer, resulting in a more uniform crack distribution, reduced crack width, and delayed main crack penetration; graphene sheets bridge the cracks to form conductive pathways, synergistically maintaining the continuity of the conductive network. This electrode is flexible and stretchable, suitable for wearable electronics, electronic skin, flexible sensors, and implantable bioelectronics.

Description

Technical Field

[0001] This invention belongs to the field of flexible and stretchable electronic devices, specifically relating to a fatigue-resistant flexible and stretchable composite electrode with crack control function and its preparation method. Background Technology

[0002] Flexible and stretchable electronic devices can operate stably under complex mechanical deformation conditions and have broad application prospects in wearable health monitoring, electronic skin, soft robots, and implantable bioelectronics. Conductive electrodes, as a key component of flexible electronic devices, not only need excellent conductivity but also must maintain stable electrical properties during stretching, bending, and torsion. However, traditional metal thin-film electrodes exhibit significant mechanical mismatch with flexible substrates, easily leading to localized stress concentrations during cyclic stretching. This induces microcrack initiation and propagation, eventually forming through-cracks, resulting in interrupted conductive paths, increased resistance, and even electrode failure, severely limiting the reliability and lifespan of flexible electronic devices.

[0003] To improve the stretchability of metal thin-film electrodes, researchers have proposed various improvement strategies, including strain-releasing structures such as serpentine, wavy, and island-bridge designs, as well as constructing composite conductive networks using metal nanowires, carbon nanotubes, and graphene. In recent years, crack engineering has become an important design strategy for stretchable metal electrodes by utilizing microcracks formed during the tensile process of metal thin films to release local strain, thereby improving the stretchability of the electrodes while maintaining the high conductivity of the metal. However, existing microcracked electrodes still suffer from problems such as continuous crack propagation and gradual instability of the conductive pathway during long-term cyclic tensile testing, and their cyclic stability and fatigue resistance still need further improvement.

[0004] Two-dimensional materials (2D materials) possess excellent mechanical properties, layered structure, and good interfacial control capabilities, attracting widespread attention in flexible electronics, electrochemical devices, and conductive composites. Graphene, in particular, exhibits excellent electrical conductivity and mechanical strength, while molybdenum disulfide (MoD) possesses a layered structure and low interlaminar shear strength. Combining these two materials can improve interfacial stress transfer and regulate crack evolution. However, currently, 2D materials are mainly used as conductive fillers, functional layers, or interfacial modification layers in flexible electronic devices. Research on introducing graphene / MoD as a sandwich layer into bilayer metal thin-film electrodes for regulating microcrack evolution and improving cyclic tensile stability is still limited, and corresponding structural design and implementation methods are lacking. Therefore, developing a flexible and stretchable composite electrode capable of regulating the evolution of microcracks in metal thin films, maintaining the continuity of conductive pathways, and improving cyclic tensile stability is of great significance. Summary of the Invention

[0005] The purpose of this invention is to overcome the technical problems of existing flexible stretchable metal thin film electrodes, such as continuous microcrack propagation, easy instability of conductive pathways, poor fatigue resistance, and short cycle life during cyclic stretching. This invention provides a fatigue-resistant flexible stretchable composite electrode with crack control function and its preparation method. This invention constructs a "double-layer gold electrode-two-dimensional material composite sandwich" structure, utilizing the regulatory effect of two-dimensional materials on the initiation, propagation, and evolution of microcracks in the metal thin film. This achieves synergistic optimization of the crack control mechanism and the two-dimensional material sandwich structure, thereby improving the electrode's conductivity stability and service reliability under cyclic stretching conditions.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for preparing a fatigue-resistant flexible stretchable composite electrode with crack control function includes the following steps:

[0008] (1) The flexible elastomer substrate is cleaned and a first layer of gold electrode is deposited on its surface;

[0009] (2) Mix graphene powder and molybdenum disulfide powder in a set ratio and disperse them in a solvent to prepare a two-dimensional material composite dispersion;

[0010] (3) The two-dimensional material composite dispersion is deposited on the surface of the first gold electrode and dried and cured to form a two-dimensional material composite sandwich layer;

[0011] (4) A second gold electrode is formed on the surface of the two-dimensional material composite sandwich layer, and the two-dimensional material composite sandwich layer is sandwiched between the first gold electrode and the second gold electrode to form a double-layer gold electrode-two-dimensional material sandwich composite structure, thereby obtaining a fatigue-resistant flexible stretchable composite electrode with crack control function.

[0012] Furthermore, the flexible elastomer substrate is a flexible elastomer substrate such as SEBS, PDMS, TPU or Ecoflex.

[0013] Further, the flexible elastomer substrate is SEBS; the cleaning treatment of the SEBS substrate in step (1) includes: ultrasonic cleaning of the SEBS substrate in deionized water, anhydrous ethanol and acetone in sequence, and drying with nitrogen.

[0014] Furthermore, in step (1), the first gold electrode layer is prepared by thermal evaporation, electron beam evaporation or magnetron sputtering, and has a thickness of 20 nm to 200 nm.

[0015] Further, the solvent in step (2) is one or more of water, ethanol, isopropanol, N-methylpyrrolidone, and N,N-dimethylformamide; the graphene is graphene powder, and the molybdenum disulfide is molybdenum disulfide powder; the mass ratio of graphene to molybdenum disulfide is 1:10 to 10:1.

[0016] Further, in step (2), the total concentration of graphene and molybdenum disulfide in the two-dimensional material composite dispersion is 0.1 mg / mL to 10 mg / mL; the dispersion is ultrasonic dispersion, the ultrasonic dispersion time is 30 min to 360 min, and the ultrasonic power is 50 W to 500 W.

[0017] Further, the deposition method in step (3) is drop coating, spray coating, spin coating, scraping coating or other liquid phase deposition methods; the deposition amount is 1 μL / cm² to 500 μL / cm².

[0018] Further, the drying and curing conditions in step (3) are: temperature 20℃~80℃, time 0.1 h~1 h; the thickness of the two-dimensional material composite interlayer is 50 nm~10 μm.

[0019] Further, in step (4), the second gold electrode is prepared by thermal evaporation, electron beam evaporation or magnetron sputtering; after the second gold electrode is formed, it is assembled by pressure application, with a pressure of 0.1 MPa to 5 MPa and a holding time of 1 min to 30 min.

[0020] Furthermore, after the pressing assembly, an annealing treatment is performed at a temperature of 60℃ to 120℃ for a time of 30 min to 120 min.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) This invention introduces a graphene / molybdenum disulfide composite sandwich between two layers of gold electrodes. By regulating the initiation and propagation behavior of microcracks in the metal film, the distribution of microcracks formed during the stretching process becomes more uniform, the crack width is reduced, the main crack propagation is delayed, and the continuity of the conductive path is improved, thereby significantly enhancing the conductivity stability and fatigue resistance of the electrode under cyclic stretching conditions. Compared with a single-layer gold electrode, the two-layer gold electrode-two-dimensional material composite sandwich structure constructed in this invention can effectively disperse the local stress generated during the stretching process, regulate the spatial distribution and evolution behavior of microcracks, and thus reduce the risk of conductive failure caused by rapid crack propagation.

[0023] (2) In this invention, graphene and molybdenum disulfide synergistically construct a two-dimensional composite sandwich. Graphene, with its excellent mechanical properties and two-dimensional sheet structure, can form a bridging effect in the microcrack region, providing a continuous load transfer and conductive path for both sides of the crack. Molybdenum disulfide, as a layered two-dimensional material, helps improve the interfacial stress distribution of the composite sandwich and helps mitigate the aggregation and irreversible stacking of graphene sheets. The synergistic effect of the two is beneficial for optimizing the crack evolution process and improving the structural and electrical stability of the composite electrode during cyclic tensile testing.

[0024] (3) The present invention uses liquid phase deposition to construct two-dimensional material composite sandwich, which has a simple preparation process and does not require complex photolithography or micro-nano processing technology. It has the advantages of low cost and good repeatability, and is easy to achieve large-area preparation.

[0025] (4) The flexible elastomer substrate used in this invention has excellent flexibility and stretchability, and the resulting composite electrode can adapt to complex deformation environments and is suitable for the field of flexible electronic devices.

[0026] (5) This invention, through the synergistic design of two-dimensional material composite sandwich and double-layer gold electrode, effectively improves the conductivity stability and service life of the electrode under large strain cyclic stretching conditions while maintaining the high conductivity of the metal film, providing a new technical approach for the design and fabrication of highly reliable flexible stretchable electronic devices. Attached Figure Description

[0027] Figure 1 The graph shows the relative resistance change (R / R0) of bilayer gold electrodes with different graphene to molybdenum disulfide mass ratios as a function of strain during the stretching process.

[0028] Figure 2 The graph shows the relative resistance change (R / R0) of a single-layer gold electrode with a graphene / molybdenum disulfide composite sandwich layer on its surface as a function of strain during the stretching process.

[0029] Figure 3 This is a schematic diagram showing the resistance change of a graphene-molybdenum disulfide composite sandwich double-layer gold electrode with a graphene mass fraction of 67% after 10,000 cycles of stretching under 100% strain conditions.

[0030] Figure 4 This is a scanning electron microscope (SEM) image of a monolayer gold electrode under 100% tensile strain.

[0031] Figure 5 Scanning electron microscope (SEM) image of a monolayer gold electrode with a graphene / molybdenum disulfide composite sandwich layer on its surface under 100% tensile strain. Detailed Implementation

[0032] Example 1 (Best Implementation): The preparation method of a fatigue-resistant flexible stretchable composite electrode with crack control function in this example is carried out according to the following steps:

[0033] 1. Cleaning treatment of the flexible SEBS substrate: The SEBS substrate was ultrasonically cleaned in deionized water, anhydrous ethanol, and acetone for 10 min each, and then dried with nitrogen. A first gold electrode layer was formed on the cleaned SEBS substrate surface by thermal evaporation under the following conditions: vacuum degree 1.0 × 10⁻⁻⁻⁻⁶. 5 Pa, the evaporation rate is 1 Å / s, and the thickness of the first gold electrode layer is 100 nm;

[0034] 2. Graphene powder and molybdenum disulfide powder were mixed at a mass ratio of 3:1 and added to a mixed solvent of water and ethanol at a volume ratio of 1:1 to prepare a mixed dispersion with a total concentration of 1 mg / mL. The dispersion was ultrasonically dispersed for 60 min under an ultrasonic power of 200 W to obtain a two-dimensional material composite dispersion.

[0035] 3. The two-dimensional material composite dispersion obtained in step 2 is drop-coated onto the surface of the first gold electrode at a rate of 100 μL / cm², and dried and cured at 60°C for 0.5 h to form a two-dimensional material composite interlayer with a thickness of about 2 μm on the surface of the first gold electrode.

[0036] Fourth, a second gold electrode is formed by thermal evaporation (the evaporation conditions are the same as in step one, and the thickness is 100 nm) and placed on the two-dimensional material composite interlayer. A pressure of 1 MPa is applied for pressing and assembly and the pressure is held for 10 min, so that the two-dimensional material composite interlayer is sandwiched between the two gold electrodes. Then, it is annealed at 80°C for 60 min to obtain a fatigue-resistant flexible stretchable composite electrode with crack control function.

[0037] In the composite electrode prepared in this embodiment, the thickness of the SEBS substrate is about 0.5 mm, the thickness of the first gold electrode layer is 100 nm, the thickness of the second gold electrode layer is 100 nm, and the thickness of the two-dimensional material composite interlayer is about 2 μm.

[0038] Example 2: The difference between this example and Example 1 is that the mass ratio of graphene powder to molybdenum disulfide powder in step two is 2:1. Other steps and parameters are the same as in Example 1.

[0039] Example 3: The difference between this example and Example 1 is that the mass ratio of graphene powder to molybdenum disulfide powder in step two is 1:1. Other steps and parameters are the same as in Example 1.

[0040] Example 4: The difference between this example and Example 1 is that the mass ratio of graphene powder to molybdenum disulfide powder in step two is 1:2. Other steps and parameters are the same as in Example 1.

[0041] Example 5: The difference between this example and Example 1 is that the mass ratio of graphene powder to molybdenum disulfide powder in step two is 1:3. Other steps and parameters are the same as in Example 1.

[0042] Comparative Example 1 (Bilayer Au): The preparation method of a flexible and stretchable bilayer gold electrode in this comparative example is carried out according to the following steps:

[0043] 1. Cleaning treatment of flexible SEBS substrate: The SEBS substrate was ultrasonically cleaned in deionized water, anhydrous ethanol and acetone for 10 min in sequence, and then dried with nitrogen.

[0044] 2. The first gold electrode layer was formed on the cleaned SEBS substrate surface by thermal evaporation under the following conditions: vacuum degree of 1.0 × 10⁻ 5 Pa, evaporation rate of 1 Å / s, thickness of 100 nm;

[0045] 3. A second gold electrode (100 nm thick) is formed directly on the surface of the first gold electrode by thermal evaporation without setting a two-dimensional material composite interlayer. A pressure of 1 MPa is applied for pressing and assembly and the pressure is held for 10 min. Then, it is annealed at 80℃ for 60 min to obtain a bilayer gold electrode (denoted as Bilayer Au).

[0046] Comparative Example 2 (Au / Gr / Au): The preparation method of a flexible and stretchable composite electrode in this comparative example is carried out according to the following steps:

[0047] 1. Cleaning treatment of the flexible SEBS substrate: The SEBS substrate was ultrasonically cleaned in deionized water, anhydrous ethanol, and acetone for 10 min each, and then dried with nitrogen. A first gold electrode layer was formed on the cleaned SEBS substrate surface by thermal evaporation under the following conditions: vacuum degree 1.0 × 10⁻⁻⁻⁻⁶. 5 Pa, evaporation rate of 1 Å / s, thickness of 100 nm;

[0048] 2. Add graphene powder to a mixed solvent of water and ethanol in a volume ratio of 1:1 to prepare a dispersion with a concentration of 1 mg / mL. Disperse the dispersion by ultrasonication for 60 min at an ultrasonic power of 200 W to obtain the graphene dispersion.

[0049] 3. The graphene dispersion obtained in step 2 is drop-coated onto the surface of the first gold electrode at a rate of 100 μL / cm², and dried and cured at 60°C for 0.5 h to form a graphene interlayer on the surface of the first gold electrode.

[0050] Fourth, a second gold electrode (100 nm thick) is formed by thermal evaporation and placed on the graphene interlayer. A pressure of 1 MPa is applied for pressing and assembly and the pressure is held for 10 min. Then, it is annealed at 80°C for 60 min to obtain a composite electrode containing a single graphene interlayer (denoted as Au / Gr / Au).

[0051] Comparative Example 3 (Au / MoS2 / Au): The preparation method of a flexible and stretchable composite electrode in this comparative example is carried out according to the following steps:

[0052] 1. Cleaning treatment of the flexible SEBS substrate: The SEBS substrate was ultrasonically cleaned in deionized water, anhydrous ethanol, and acetone for 10 min each, and then dried with nitrogen. A first gold electrode layer was formed on the cleaned SEBS substrate surface by thermal evaporation under the following conditions: vacuum degree 1.0 × 10⁻⁻⁻⁻⁶. 5 Pa, evaporation rate of 1 Å / s, thickness of 100 nm;

[0053] 2. Add molybdenum disulfide powder to a mixed solvent of water and ethanol in a volume ratio of 1:1 to prepare a dispersion with a concentration of 1 mg / mL. Disperse the dispersion by ultrasonication for 60 min at an ultrasonic power of 200 W to obtain the molybdenum disulfide dispersion.

[0054] 3. The molybdenum disulfide dispersion obtained in step 2 is drop-coated onto the surface of the first gold electrode at a rate of 100 μL / cm², and dried and cured at 60°C for 0.5 h to form a molybdenum disulfide interlayer on the surface of the first gold electrode.

[0055] Fourth, a second gold electrode (100 nm thick) is formed by thermal evaporation and placed on the molybdenum disulfide interlayer. A pressure of 1 MPa is applied for pressing and assembly and the pressure is held for 10 min. Then, it is annealed at 80°C for 60 min to obtain a composite electrode containing a single molybdenum disulfide interlayer (denoted as Au / MoS2 / Au).

[0056] Comparative Example 4 (Au / Gr-MoS2): The preparation method of a flexible and stretchable composite electrode in this comparative example is carried out according to the following steps:

[0057] 1. Cleaning treatment of the flexible SEBS substrate: The SEBS substrate was ultrasonically cleaned in deionized water, anhydrous ethanol, and acetone for 10 min each, and then dried with nitrogen. A first gold electrode layer was formed on the cleaned SEBS substrate surface by thermal evaporation under the following conditions: vacuum degree 1.0 × 10⁻⁻⁻⁻⁶. 5 Pa, evaporation rate of 1 Å / s, thickness of 100 nm;

[0058] 2. Graphene powder and molybdenum disulfide powder were mixed at a mass ratio of 3:1 (the same ratio as in Example 1), and added to a mixed solvent of water and ethanol at a volume ratio of 1:1 to prepare a mixed dispersion with a total concentration of 1 mg / mL. The dispersion was ultrasonically dispersed for 60 min under an ultrasonic power of 200 W to obtain a two-dimensional material composite dispersion.

[0059] 3. The two-dimensional material composite dispersion obtained in step 2 is drop-coated onto the surface of the first gold electrode at a rate of 100 μL / cm², and dried and cured at 60°C for 0.5 h to form a two-dimensional material composite sandwich layer on the surface of the first gold electrode layer. No second gold electrode layer is set, resulting in a single-layer gold / two-dimensional material composite sandwich electrode (denoted as Au / Gr-MoS2).

[0060] Performance testing

[0061] (a) Tensile conductivity test: The electrode samples prepared in Examples 1-5 and Comparative Examples 1-4 were placed on a universal tensile testing machine for tensile testing. The relative resistance change (R / R0) was recorded in real time using a digital source meter. The tensile rate was 10 mm / min, and the samples were continuously stretched from the initial state. The resistance change with strain was recorded throughout the process. Each sample was tested three times, and the average value was taken. The test environment was room temperature (25 ± 2 ℃).

[0062] The curves showing the relative resistance change (R / R0) as a function of strain during the tensile process in Examples 1-5 and Comparative Examples 1-3 are as follows: Figure 1 As shown. From Figure 1 It can be seen that the R / R0 ratio of each embodiment increases with the increase of tensile strain. Among them, the R / R0 ratio of Example 1 (graphene:molybdenum disulfide = 3:1) remains at the lowest level, while the R / R0 ratio of Comparative Example 1 (Bilayer Au) is the highest. This indicates that the addition of two-dimensional materials improves the tensile conductivity of the bilayer gold electrode, and the mass ratio of graphene to molybdenum disulfide has a significant impact on the conductivity stability of the composite sandwich. The crack control effect of the composite sandwich is best at a ratio of 3:1.

[0063] The curve of relative resistance change (R / R0) as a function of strain during the tensile process for Comparative Example 4 (a monolayer gold electrode with a graphene / molybdenum disulfide composite coating on its surface) is shown below. Figure 2 As shown. From Figure 2 It can be seen that the relative resistance of the single-layer gold electrode with graphene / molybdenum disulfide composite coating on the surface continues to increase during the stretching process. Its R / R0 is significantly higher than that of Examples 1-5 and Comparative Examples 1-3 with double-layer gold electrode structure, indicating that the second layer gold electrode can effectively maintain the continuity of the conductive path and improve the conductivity stability of the composite electrode during the stretching process.

[0064] 10,000 Cyclic Tensile Test: The composite electrode prepared in Example 1 (graphene to molybdenum disulfide mass ratio of 3:1) was subjected to 10,000 cyclic tensile tests under 100% strain conditions, and the resistance change signal was recorded in real time. The results are as follows: Figure 3 As shown. From Figure 3 It can be seen that during 10,000 cycles under 100% tensile strain, the relative resistance change of the composite electrode remained within a small range, and no sudden change in resistance or conductivity failure occurred. This indicates that the double-layer gold / graphene-molybdenum disulfide composite sandwich structure constructed in this invention has excellent cycle stability and resistance to mechanical fatigue.

[0065] Microcrack morphology characterization: Unmodified monolayer gold electrodes and monolayer gold electrodes with a graphene / molybdenum disulfide composite coating were observed under 100% tensile strain using scanning electron microscopy (SEM). The results are as follows: Figure 4 and Figure 5 As shown.

[0066] from Figure 4 It can be seen that the unmodified monolayer gold electrode develops wide and deep cracks on its surface under 100% tensile strain, and the cracks are distributed throughout the surface. From Figure 5 It can be seen that, under the same tensile strain, the monolayer gold electrode modified with the graphene / molybdenum disulfide composite coating forms a large number of uniformly distributed fine cracks, with a significantly reduced crack width, and no penetrating main cracks were observed. Compared to Figure 4 The invention illustrates a wide and deep through-crack formed by an unmodified monolayer gold electrode. This invention disperses locally concentrated strain across multiple microcrack regions, reducing stress concentration at the tip of a single main crack. Simultaneously, graphene sheets distributed within the composite interlayer bridge the microcracks, providing additional conductive pathways to both sides of the crack, further inhibiting crack opening and penetration, thereby maintaining the continuity of the conductive pathways.

[0067] comprehensive Figures 1-5As can be seen, this invention achieves effective control over the initiation and propagation behavior of cracks in metal thin films by introducing a graphene / molybdenum disulfide composite interlayer between two layers of gold electrodes, forming a uniform and dense microcrack network and suppressing the formation of penetrating main cracks. Simultaneously, the graphene sheets cross the cracks to form bridging conductive pathways, synergistically maintaining the conductivity stability of the electrodes under tensile conditions, thereby significantly improving the conductivity stability and mechanical fatigue resistance of the composite electrode under high strain and cyclic tensile conditions.

Claims

1. A method for preparing a fatigue-resistant flexible stretchable composite electrode with crack control function, characterized in that, The preparation method is carried out according to the following steps:

1. The flexible elastomer substrate is cleaned, and a first layer of gold electrode is deposited on the surface of the cleaned flexible elastomer substrate.

2. Graphene and molybdenum disulfide are mixed in a certain proportion and dispersed in a solvent to prepare a two-dimensional material composite dispersion.

3. The two-dimensional material composite dispersion obtained in step 2 is deposited on the surface of the first gold electrode layer, and then dried and cured to form a two-dimensional material composite sandwich layer on the surface of the first gold electrode layer. Fourth, place the second gold electrode on the surface of the two-dimensional material composite sandwich layer, so that the two-dimensional material composite sandwich layer is sandwiched between the first gold electrode and the second gold electrode, forming a double-layer gold electrode-two-dimensional material composite sandwich layer structure, and obtain a fatigue-resistant flexible stretchable composite electrode with crack control function.

2. The preparation method according to claim 1, characterized in that, The flexible elastomer substrate is a flexible elastomer substrate such as SEBS, PDMS, TPU or Ecoflex; when the flexible elastomer substrate is SEBS, the cleaning treatment of the SEBS substrate in step one includes: ultrasonically cleaning the SEBS substrate in deionized water, anhydrous ethanol and acetone in sequence, and drying it with nitrogen.

3. The preparation method according to claim 1, characterized in that, In step one, the first gold electrode layer is prepared by thermal evaporation, electron beam evaporation or magnetron sputtering, with a thickness of 20 nm to 200 nm; in step four, the second gold electrode layer is prepared by thermal evaporation, electron beam evaporation or magnetron sputtering.

4. The preparation method according to claim 1, characterized in that, The solvent mentioned in step two is one or more of water, ethanol, isopropanol, N-methylpyrrolidone, and N,N-dimethylformamide; the graphene is graphene powder, and the molybdenum disulfide is molybdenum disulfide powder; the mass ratio of graphene to molybdenum disulfide is 1:10 to 10:1; the total concentration of graphene and molybdenum disulfide in the two-dimensional material composite dispersion is 0.1 mg / mL to 10 mg / mL.

5. The preparation method according to claim 1, characterized in that, The dispersion described in step two is ultrasonic dispersion, with an ultrasonic dispersion time of 30 min to 360 min and an ultrasonic power of 50 W to 500 W.

6. The preparation method according to claim 1, characterized in that, The deposition method described in step three is drop coating, spray coating, spin coating, blade coating or other liquid phase deposition methods; the deposition amount is 1 μL / cm² to 500 μL / cm²; the drying and curing conditions are: temperature 20℃ to 80℃, time 0.1 h to 1 h; the thickness of the two-dimensional material composite interlayer is 50 nm to 10 μm.

7. The preparation method according to claim 1, characterized in that, After placing the second gold electrode on the surface of the two-dimensional material composite sandwich layer in step four, a pressing assembly is performed, with a pressure of 0.1 MPa to 5 MPa and a holding time of 1 min to 30 min. After the pressing assembly, an annealing treatment is performed, with an annealing temperature of 60℃ to 120℃ and an annealing time of 30 min to 120 min.

8. A fatigue-resistant flexible stretchable composite electrode with crack control function, characterized in that, It is prepared by any one of claims 1 to 7.

9. The composite electrode according to claim 8, characterized in that, The composite electrode has a sandwich structure consisting of a flexible elastomer substrate, a first gold electrode layer, a graphene-molybdenum disulfide composite interlayer, and a second gold electrode layer; the graphene and molybdenum disulfide are dispersed in the two-dimensional material composite interlayer in a sheet-like form.

10. The application of the composite electrode of claim 8 or 9 in flexible electronic devices.

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