A gallium-based liquid metal, stretchable circuit lead, and method of making the same

Abstract

The application discloses a gallium-based liquid metal, a stretchable circuit lead and a preparation method thereof, and belongs to the technical field of materials. The product is provided with a protective layer composed of particles containing a gallium oxide shell. The product has ideal conductivity, thermal conductivity and fatigue resistance, and has high durability and reliability when applied to the stretchable circuit lead. Meanwhile, the printing precision of the liquid metal is high, and the design application range of the stretchable circuit lead is wide.

Description

Technical Field

[0001] This invention relates to the field of materials technology, specifically to a gallium-based liquid metal, a stretchable circuit lead, and a method for preparing the same. Background Technology

[0002] In the fabrication of flexible electronic devices, liquid metal has long been considered an ideal material for circuit lead fabrication due to its combination of conductivity and fluidity. However, traditional liquid metals are difficult to print with inks, generally requiring the doping of with modifying materials such as metals or graphite to reduce their surface tension. But this approach significantly reduces the intrinsic conductivity and thermal conductivity of the liquid metal, and the precision after ink printing is relatively low, making it difficult to apply in some high-precision patterned designs. In addition, doping modification also reduces the mechanical strength of the liquid metal itself, so even if the material is fabricated into stretchable flexible circuit leads, there is still a risk of severe deformation under external force, which greatly limits its application. Summary of the Invention

[0003] In view of the deficiencies of the existing technology, the purpose of this invention is to provide a gallium-based liquid metal. This product, by setting a protective layer composed of gallium oxide shell particles, not only has ideal electrical and thermal conductivity and fatigue resistance, but also has high durability and reliability when applied to stretchable circuit leads. At the same time, the liquid metal has high printing precision, and the design and application range of the stretchable circuit leads is wide.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A gallium-based liquid metal, including a gallium-based liquid alloy;

[0006] The gallium-based liquid alloy comprises a matrix alloy and gallium oxide;

[0007] The gallium-based liquid alloy has particles on its surface, and the particles contain a gallium oxide shell.

[0008] The average particle size of the particles is ≤8μm;

[0009] The gallium-based liquid metal contains ≥2% gallium oxide by mass.

[0010] In a second aspect, the present invention also provides a method for preparing gallium-based liquid metal, comprising the following steps:

[0011] Provides molten base alloy;

[0012] The base alloy was stirred in air to obtain gallium-based liquid metal.

[0013] In a third aspect, the present invention also provides a stretchable circuit lead comprising a substrate and a gallium-based liquid metal.

[0014] The beneficial effects of this invention are that it provides a gallium-based liquid metal. This product, by setting a protective layer composed of particles containing a gallium oxide shell, not only has ideal electrical and thermal conductivity and fatigue resistance, but also has high durability and reliability when applied to stretchable circuit leads. At the same time, the liquid metal has high printing precision, and the design and application range of the stretchable circuit leads is wide. Attached Figure Description

[0015] Figure 1 This is a morphological illustration of the particles in the gallium-based liquid metal obtained in Example 1 of the present invention.

[0016] Figure 2 These are magnified morphological observations of the products obtained in Embodiment 1 and Comparative Examples 1-2 of the present invention.

[0017] Figure 3 This is a schematic diagram of the fatigue resistance test performed on the stretchable circuit leads obtained in Embodiment 1 of the present invention.

[0018] Figure 4 The image shows the results of fatigue resistance testing on the stretchable circuit leads obtained in Embodiment 1 of the present invention. Detailed Implementation

[0019] To better illustrate the purpose, technical solution, and advantages of this invention, the invention will be further described below with reference to specific embodiments and comparative examples. The purpose of this description is to provide a detailed understanding of the invention, not to limit its scope. All other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this invention. Unless otherwise specified, the experimental reagents and instruments involved in the implementation of this invention are commonly used reagents and instruments.

[0020] In this invention, the technical features described in an open-ended manner include both closed-ended technical solutions composed of the listed features and open-ended technical solutions that include the listed features.

[0021] In this invention, numerical ranges are involved. Unless otherwise specified, the numerical ranges are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to an integer, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are included.

[0022] The present invention is further illustrated below with specific embodiments:

[0023] A gallium-based liquid metal, including a gallium-based liquid alloy;

[0024] The gallium-based liquid alloy comprises a matrix alloy and gallium oxide;

[0025] The gallium-based liquid alloy has particles on its surface, and the particles contain a gallium oxide shell.

[0026] The average particle size of the particles is ≤8μm;

[0027] The gallium-based liquid metal contains ≥2% gallium oxide by mass.

[0028] The use of liquid metal for the fabrication of stretchable circuit leads is not uncommon. However, the products prepared by these technologies have limited applications and low quality. The main reason is that the surface tension of liquid metal is too high when it is used for ink printing, making it difficult to achieve ideal printing accuracy. Currently, common liquid metal printing technologies are mainly divided into the following categories: (1) ink printing after doping modification, which is to mix liquid metal with other metals or graphite materials to reduce the printing difficulty. However, this approach will significantly affect the conductivity and thermal conductivity of the product; (2) direct printing technology, which is to print liquid metal without introducing any doping components, by setting special substrates and printing equipment, to maintain the conductivity and thermal conductivity of the liquid metal itself. However, this approach cannot achieve universality, has high requirements for equipment and processes, and is difficult to produce; (3) electrodeposition method, which is to set liquid metal on the substrate by electrodeposition, and solve the printing accuracy problem by setting precise programs and high integration. However, this approach is difficult to control the situation of coarse grains and uneven porosity of individual deposits, and the quality of the product is difficult to guarantee. Addressing the limitations of existing technologies, this invention utilizes a gallium-based liquid alloy as a substrate. By setting a protective layer on its surface with small-sized gallium oxide-containing particles, it effectively reduces the overall surface tension of the gallium-based liquid metal, improving its precision during ink printing. Simultaneously, it maintains ideal electrical and thermal conductivity, making it highly suitable for fabricating stretchable circuit leads. Furthermore, this stretchable circuit lead, based on this non-uniformly doped liquid metal design, exhibits high mechanical strength and durability, a long service life, and a high overall cost-performance ratio.

[0029] In some embodiments, the average particle size is 2 to 8 μm.

[0030] Specifically, the average particle size is a range of one or any two of the following: 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, and 8μm.

[0031] In some embodiments, the gallium oxide content in the gallium-based liquid metal is 2-4% by mass.

[0032] Specifically, the mass content of gallium oxide in the gallium-based liquid metal is one or any two of the following values: 2%, 2.2%, 2.5%, 2.8%, 3%, 3.2%, 3.5%, 3.8%, and 4%.

[0033] In some embodiments, the average particle size is 2-4 μm, and the gallium oxide content in the gallium-based liquid metal is 2-3% by mass.

[0034] The average particle size of the gallium oxide shell and the gallium oxide content in the product affect the relative thickness of the protective layer and the coverage and density of the liquid metal alloy. If the particles are too small or the gallium oxide content is too low, the surface tension of the gallium-based liquid metal will be too high, making it difficult to use for ink printing. However, if the particles are too large or the gallium oxide content is too high, the electrical and thermal conductivity of the gallium-based liquid metal may be reduced, affecting the intrinsic performance of the material. When the gallium oxide content and amount are selected within the above range, the overall performance of the gallium-based liquid metal is better.

[0035] In some embodiments, the average particle size and the mass content of gallium oxide in the gallium-based liquid metal can be determined by: pre-confirming the position and size of the particles using EDS, then switching to an optical microscope to locate the particles, measuring the particle size using image analysis software, testing 200 particles, and finally calculating the average value, which is the average particle size of gallium oxide; performing XPS analysis on the gallium-based liquid metal and confirming the mass content of gallium and oxygen elements in non-elemental valence states, thereby calculating the corresponding mass content of gallium oxide.

[0036] In some embodiments, the particle size is 0.5 to 10 μm.

[0037] In some embodiments, the viscosity of the gallium-based liquid metal is ≥1×10⁻⁶. 2 mPa.s.

[0038] Based on the oxide layer design, the viscosity of the gallium-based liquid metal described in this invention is significantly increased compared to that of pure gallium-based liquid alloys (the viscosity of general gallium-based liquid metals is less than 10 mPa·s), thus significantly improving printing accuracy.

[0039] In some embodiments, the viscosity of the gallium-based liquid metal is 1 × 10⁻⁶. 2 ~2×10 5 mPa.s.

[0040] In some embodiments, the viscosity test method of the gallium-based liquid metal is based on the national standard "Methods for Determination of Physical Properties of Liquid Metals Part 3: Determination of Density", and the corresponding test instrument is the NDJ-5S(8S) digital display viscometer.

[0041] In some embodiments, the conductivity of the gallium-based liquid metal is 0.5 × 10⁻⁶. 6 ~1.5×10 6 S / m, thermal conductivity 15.5×10 6 ~19×10 6 W / mK.

[0042] Specifically, in some embodiments, the conductivity of the gallium-based liquid metal is 0.5 × 10⁻⁶. 6 S / m, 0.6×10 6 S / m, 0.7×10 6 S / m, 0.8×10 6 S / m, 0.9×10 6 S / m, 1×10 6 S / m, 1.1×10 6 S / m, 1.2×10 6 S / m, 1.3×10 6 S / m, 1.4×10 6 S / m, 1.5×10 6 A value within the range of one or both of S / m, with a thermal conductivity of 15.5 × 10⁻⁶. 6 W / mK, 16×10 6 W / mK, 16.5×10 6 W / mK, 17×10 6 W / mK, 17.5×10 6 W / mK, 18×10 6 W / mK, 18.5×10 6 W / mK, 19×10 6 The range value of one or both of W / mK.

[0043] With the configuration of the structure described in this invention, the gallium-based liquid metal has ideal thermal conductivity and electrical conductivity, fully meeting the requirements for use of stretchable circuit leads in existing flexible electronic devices.

[0044] In some embodiments, the test method for the electrical conductivity of the gallium-based liquid metal refers to the national standard "Methods for Determination of Physical Properties of Liquid Metals Part 2: Determination of Electrical Conductivity", which adopts the DC four-probe method. The test instruments include an Agilent 34420A digital multimeter and a KEITHLEY-6221AC / DC current source. The test method for thermal conductivity refers to the ISO22007-2 test standard, which uses a Hot Disk TPS 2500S device.

[0045] In some embodiments, the base alloy includes at least one of gallium-indium alloy and gallium-indium-tin alloy.

[0046] In some embodiments, the mass content of gallium in the matrix alloy is ≥60%.

[0047] Specifically, when the matrix is ​​a gallium-indium alloy, the mass content of gallium is 60-80%; when the matrix is ​​a gallium-indium-tin alloy, the mass content of gallium is 60-70% and the mass content of indium is 25-30%.

[0048] In the experiment, the inventors discovered that different compositions of the base alloy result in different properties of the surface, such as viscosity, electrical conductivity, and thermal conductivity, after the protective layer is applied. In order to achieve better ink printing and usage effects, products prepared with base alloys within the above range have better performance.

[0049] Specifically, the base alloy is a gallium-indium-tin alloy, and the mass ratio of gallium, indium and tin in the base alloy is one or any two of the following: (70:25:5), (65:25:10) and (60:30:10).

[0050] In a specific embodiment, the present invention also discloses a method for preparing gallium-based liquid metal, comprising the following steps:

[0051] Provides molten base alloy;

[0052] The base alloy was stirred in air to obtain gallium-based liquid metal.

[0053] Traditional methods for preparing modified liquid metals often involve directly doping and mixing modifying substances into a liquid alloy. While this approach can improve the uniformity of the overall composition and printing efficiency, it also directly affects the intrinsic performance of the liquid metal. To overcome this drawback, the present invention uses a molten base alloy to dope the product with oxides through surface oxidation. Simultaneously, the protective layer containing gallium oxide particles does not penetrate into the base alloy, thus improving the overall surface tension of the material while maintaining high levels of electrical and thermal conductivity. The preparation method is simple to operate and can be scaled up for industrial production.

[0054] In some embodiments, the molten matrix alloy is obtained by heating and melting a single metal and then ultrasonically treating it.

[0055] Specifically, the temperature during heating and melting is 500–700°C, the temperature during ultrasonic treatment is set to 70–100°C, and the ultrasonic treatment time is 0.5–1 hour.

[0056] Specifically, the elemental metal includes at least one of gallium, indium, and tin.

[0057] In some embodiments, the base alloy is stirred in air until the viscosity of the gallium-based liquid metal reaches 1 × 10⁻⁶. 2 ~2×10 5 mPa.s.

[0058] Specifically, the stirring process is a magnetic stirring process.

[0059] Specifically, the temperature during the stirring process is 20–30°C.

[0060] Specifically, the stirring speed during the stirring process is ≥300 rpm.

[0061] In some embodiments, the stirring speed during the stirring process is 300 to 600 rpm.

[0062] Micro-oxidation of a liquid matrix alloy can be achieved by stirring without the need for special equipment. However, the stirring speed affects the flow of the liquid alloy. To ensure that the liquid matrix alloys on different layers participate in the micro-oxidation reaction and that the reaction degree is similar, the stirring speed cannot be too low. Studies have found that stirring at the speed mentioned above can result in better product quality.

[0063] In some embodiments, the stirring process takes 20 to 50 minutes.

[0064] During micro-oxidation treatment, the number of particles gradually increases over time, and the longer the treatment time, the greater the probability of particle agglomeration, ultimately leading to the formation of large particles. This not only affects the overall uniformity of the material but also directly impacts the product's electrical and thermal conductivity. Research has found that when using the stirring treatment time within the aforementioned range, the quality of the gallium oxide shell formation and the appropriate particle size are superior.

[0065] In some embodiments, the present invention also provides a stretchable circuit lead comprising the gallium-based liquid metal.

[0066] The gallium-based liquid metal described in this invention not only has good ink printing effect and high precision, but also retains high thermal conductivity and electrical conductivity. When applied to the preparation of stretchable circuit leads, it is far superior to existing similar doped and modified products in terms of production cost, production efficiency and product quality, and has a high overall cost performance.

[0067] In some embodiments, the stretchable circuit leads also include a substrate.

[0068] Specifically, the substrate includes at least one of a TPU substrate, a PDMS substrate, a VHB substrate, a PC substrate, and a polyamide substrate.

[0069] In some embodiments, the substrate includes a first substrate and a second substrate, and the gallium-based liquid metal is disposed between the first substrate and the second substrate.

[0070] Based on the superior printing and usage performance of the gallium-based liquid metal described in this invention, the stretchable circuit leads described in this invention can be constructed using a "sandwich structure". With the protection of the encapsulation sandwich between two substrates, the durability and reliability of the product can be effectively improved. After the sandwich design with elastic substrates, the circuit leads can still remain intact after various external force deformations, exhibiting high stability.

[0071] In some embodiments, the stretchable circuit leads are subjected to a tensile test at a tensile frequency of 0.125 Hz and a tensile rate of 100%, and the number of times the resistance value remains unchanged after stretching is ≥1000.

[0072] The product described in this invention is based on the selection of gallium-based liquid metal and the "sandwich structure" configuration design, which has high tensile strength and high resilience. It can maintain normal working performance after 1000 tensile treatments, has excellent fatigue resistance, and a long service life.

[0073] In some embodiments, the gallium-based liquid metal is deposited on a substrate by at least one of the following methods: scraping, brushing, printing, spin coating, inkjet printing, and 3D printing.

[0074] The present invention is further illustrated below with specific embodiments, which should not be construed as limiting the scope of protection claimed by the present invention:

[0075] Unless otherwise specified, all embodiments and comparative examples are commercially available products.

[0076] Example 1

[0077] An embodiment of the gallium-based liquid metal, stretchable circuit leads, and their fabrication method described in this invention includes the following steps:

[0078] (1) Set up the molten matrix alloy: weigh elemental gallium, elemental indium and elemental tin in a mass ratio of 70:25:5, grind off the surface oxide layer, mix them in a quartz crucible and heat to 800℃ under an inert protective atmosphere to melt. Then, place the crucible in an ultrasonic instrument and set it to 100℃ for 1h under an inert protective atmosphere to obtain the molten gallium-based liquid alloy.

[0079] (2) Particles are set on the surface of the matrix alloy by oxidation: 300g of gallium-based liquid alloy is placed in a beaker equipped with a magnetic stirrer, and then stirred at 500rpm for 20min for micro-oxidation to obtain the gallium-based liquid metal; the particles are as follows Figure 1 As shown, the interior is a liquid gallium-based metal alloy, while the outer layer is a gallium oxide layer formed by oxidation.

[0080] Example 2

[0081] An embodiment of the gallium-based liquid metal, stretchable circuit leads and their preparation method described in this invention differs from Embodiment 1 only in that the stirring time in step (2) is 30 min.

[0082] Example 3

[0083] An embodiment of the gallium-based liquid metal, stretchable circuit leads and their preparation method described in this invention differs from Embodiment 1 only in that the stirring time in step (2) is 40 min.

[0084] Example 4

[0085] An embodiment of the gallium-based liquid metal, stretchable circuit leads and their preparation method described in this invention differs from Embodiment 1 only in that the stirring time in step (2) is 50 min.

[0086] Example 5

[0087] An embodiment of the gallium-based liquid metal, stretchable circuit leads and their preparation method described in this invention differs from Embodiment 1 only in that, in step (1), elemental gallium, elemental indium and elemental tin are in a mass ratio of 65:25:10.

[0088] Example 6

[0089] An embodiment of the gallium-based liquid metal, stretchable circuit leads and their preparation method described in this invention differs from Embodiment 1 only in that, in step (1), elemental gallium, elemental indium and elemental tin are in a mass ratio of 60:30:10.

[0090] Comparative Example 1

[0091] A method for preparing gallium-based liquid metal differs from Example 1 only in that the stirring time in step (2) is 10 min.

[0092] Comparative Example 2

[0093] A method for preparing gallium-based liquid metal differs from Example 1 only in that the stirring time in step (2) is 60 min.

[0094] Comparative Example 3

[0095] A method for preparing gallium-based liquid metal differs from Example 1 only in that, in step (1), elemental gallium, elemental indium, and elemental tin are prepared in a mass ratio of 50:40:10.

[0096] Comparative Example 4

[0097] A method for preparing gallium-based liquid metal differs from Example 1 only in that the stirring rate in step (2) is 300 rpm.

[0098] Example of effect 1

[0099] To verify the properties of the gallium-based liquid metal described in this invention, the viscosity, electrical conductivity, and thermal conductivity of the products obtained in each embodiment and comparative example were tested (with the gallium-based liquid alloy prepared in Example 1 as a control). At the same time, the mass content of gallium oxide and the average particle size in the products were tested, and the results are shown in Table 1.

[0100] Table 1

[0101]

[0102] The test results clearly show that the gallium-based liquid metal described in this invention has a significantly lower surface tension and a much higher viscosity, several orders of magnitude higher, compared to pure gallium-based liquid alloys. Furthermore, the electrical and thermal conductivity of the product remains at the same order of magnitude, demonstrating excellent overall performance. The highest electrical conductivity of the product can reach 1.28 × 10⁻⁶.6 S / m, with a thermal conductivity reaching up to 17.12×10 6 W / mK. As can be seen from Examples 1-4 and Comparative Examples 1-2, the relative content of gallium oxide in the product gradually increases with increasing oxidation time. However, comparing the magnified morphology of the products from Comparative Example 1 (10 min), Example 1 (20 min), and Comparative Example 2 (60 min), as shown... Figure 2 As shown, with increasing oxidation time, the size of gallium oxide particles increased significantly, and even some agglomeration occurred. This affected the intrinsic electrical and thermal conductivity of the product, especially the electrical conductivity, which decreased to 0.2 × 10⁻⁶ compared to the product of Example 1. 6 The S / m value is almost at the critical order of magnitude, which is not conducive to its subsequent application in stretchable circuit leads.

[0103] Meanwhile, as can be seen from Examples 1, 5-6 and Comparative Example 3, the composition of gallium-based liquid alloys also affects the formation of gallium oxide. When the gallium content is too low, the surface formation probability of gallium oxide will also decrease. Even if the oxidation time is the same, the gallium oxide content in the product is far from meeting the corresponding standard (the inventors have verified that even if the stirring time of the process of Comparative Example 3 is extended to 60 minutes, it still cannot reach the level of Example 1 and does not meet the requirements of this invention). Although other metals will also generate oxides at this time, the degree of surface tension modification of the product is low, and the electrical conductivity and thermal conductivity of the product are still low when the gallium oxide content is low, so the application performance of the product cannot meet the standard.

[0104] Furthermore, if the stirring rate is too low during the product preparation process, the formation effect of gallium oxide in the product cannot meet the requirements of this invention. As shown in Comparative Example 4, the inventors have verified that even if the stirring time is extended to 60 minutes at this rate, the gallium oxide content in the product still cannot reach the ideal effect. In some cases, the individual gallium oxide particles agglomerate too much due to the slow stirring rate.

[0105] Example 2

[0106] To verify the effectiveness of the gallium-based liquid metal described in this invention, stretchable circuit leads were fabricated using the gallium-based liquid metals prepared in Examples 1-4 and Comparative Examples 1-3. A VHB substrate measuring 80×10×5mm was taken, using a 3M 4905 model. Gallium-based liquid metal was then poured onto a customized screen printing plate on one of the substrates. The customized pattern consisted of long lines with line widths ranging from 10 to 500 μm. A screen printing mesh count of 200 or higher was used, and the metal was repeatedly coated twice from top to bottom using a squeegee. The printed pattern size was 40×2×0.5mm. The printing resolution of each example and comparative example was confirmed, and the results are shown in Table 2. If any phenomenon occurred, such as the gallium-based liquid metal failing to pass through the screen printing plate, the printed pattern breaking, or the gallium-based liquid metal failing to adhere to the substrate, the result was not recorded and indicated by " / ".

[0107] Table 2

[0108]

[0109] The test results show that, corresponding to the viscosity of the product, the higher the viscosity, the higher the printing resolution of the product. All products in the examples can achieve a printing resolution of 20μm, which is highly accurate. However, the products in Comparative Examples 1 and 3 have lower viscosity due to insufficient gallium oxide content, and the printing accuracy of the products does not meet the requirements.

[0110] Subsequently, another identical substrate was overlaid on the printed pattern of Example 1 to form a stretchable circuit lead with a "sandwich structure." Fatigue resistance testing was then performed on the product. Figure 3 As shown, a test platform was built using a 57-56-8D25-2.5M stepper motor and an RXP45-L200 linear slider module. The test instruments were purchased from Chengdu Liandong Ruixin Technology Co., Ltd. Customized fixtures clamped the stretchable circuit leads, which were connected via copper foil. A benchtop multimeter (Keithley DAQ 6510) was connected to the copper foil to record the resistance change during the stretching process. The stretching frequency was 0.125Hz, the number of stretches was 1000, and the stretching deformation rate was 200%. The resistance value of the product was simultaneously measured. The results are as follows: Figure 4 As shown, after 1000 cycles of 200% tensile deformation, the product's resistance value hardly changes, and no cracks appear on the product's appearance, indicating that the product has high resilience and resistance to external forces, and excellent fatigue resistance.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A gallium-based liquid metal, characterized in that, Including gallium-based liquid alloys; The gallium-based liquid alloy comprises a matrix alloy and gallium oxide; The gallium-based liquid alloy has particles on its surface, and the particles contain a gallium oxide shell. The average particle size of the particles is ≤8μm; The gallium-based liquid metal contains ≥2% gallium oxide by mass.

2. The gallium-based liquid metal as described in claim 1, characterized in that, The average particle size of the particles is 2–8 μm.

3. The gallium-based liquid metal as described in claim 1, characterized in that, The gallium oxide content in the gallium-based liquid metal is 1-4% by mass.

4. The gallium-based liquid metal as described in claim 1, characterized in that, The viscosity of the gallium-based liquid metal is ≥1×10⁻⁶. 2 mPa.s.

5. The gallium-based liquid metal as described in claim 4, characterized in that, The viscosity of the gallium-based liquid metal is 1×10⁻⁶. 2 ~2×10 5 mPa.s.

6. The gallium-based liquid metal as described in claim 1, characterized in that, The conductivity of the gallium-based liquid metal is 0.5 × 10⁻⁶. 6 ~1.5×10 6 S / m; and / or, thermal conductivity of 15.5 × 10⁻⁶ 6 ~19×10 6 W / mK.

7. The gallium-based liquid metal as described in claim 1, characterized in that, The matrix alloy includes at least one of gallium-indium alloy and gallium-indium-tin alloy.

8. The gallium-based liquid metal as described in claim 7, characterized in that, In the matrix alloy, the mass content of gallium is ≥60%.

9. The gallium-based liquid metal as described in claim 1, characterized in that, The particle core comprises a matrix alloy, and the outer shell comprises gallium oxide.

10. The method for preparing gallium-based liquid metal according to any one of claims 1 to 8, characterized in that, Includes the following steps: Provides molten base alloy; The base alloy was stirred in air to obtain gallium-based liquid metal.

11. The method for preparing gallium-based liquid metal as described in claim 10, characterized in that, The base alloy was stirred in air until a viscosity of 1×10⁻⁶ was obtained. 2 ~2×10 5 Gallium-based liquid metal at mPa·s.

12. The method for preparing gallium-based liquid metal as described in claim 10, characterized in that, The stirring speed during the stirring process is ≥300 rpm; and / or the stirring time is 20 to 50 min.

13. A stretchable circuit lead, characterized in that, Includes the gallium-based liquid metal according to any one of claims 1 to 8.

14. The stretchable circuit lead as described in claim 13, characterized in that, The stretchable circuit leads also include a substrate.

15. The stretchable circuit lead as described in claim 14, characterized in that, The substrate includes a first substrate and a second substrate, and the gallium-based liquid metal is disposed between the first substrate and the second substrate.

16. The stretchable circuit lead as described in claim 15, characterized in that, The first substrate and / or the second substrate are any one of TPU substrate, PDMS substrate, VHB substrate, PC substrate and polyamide substrate.

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