Carbon aerogel, carbon aerogel-based elastomer as well as preparation method and application of carbon aerogel-based elastomer

Abstract

The invention discloses carbon aerogel, a carbon aerogel-based elastomer as well as a preparation method and application of the carbon aerogel-based elastomer. The preparation method of the carbon aerogel comprises the following steps: placing cotton soaked in a nickel salt solution in a high-temperature area of a double-temperature-area tubular furnace, placing powdered sulfur and polyolefin in a low-temperature area of the double-temperature-area tubular furnace, and heating to obtain the carbon aerogel. A carbon aerogel-based elastomer obtained by packaging the prepared carbon aerogel and an elastomer shows a wide deformation range and near-linear electromechanical response characteristics, and shows high sensitivity in adhesive force detection and joint movement monitoring; the strain direction and amplitude can be reliably distinguished, and meanwhile the wide bidirectional strain range and the high sensitivity are achieved.

Description

Technical Field

[0001] This invention specifically relates to a carbon aerogel, a carbon aerogel-based elastomer, its preparation method, and its application. Background Technology

[0002] Flexible sensors, as core components of flexible electronic systems, demonstrate immense application potential in fields such as smart electronic skin, wearable devices, medical health monitoring, and human-computer interaction by detecting external physical stimuli or physiological parameters. Compared to traditional rigid sensors, their manufacturing process is relatively simple, and they possess excellent production efficiency and reliable output performance. They are particularly adept at adapting to irregular or dynamically changing test surfaces, thus becoming an important development direction for next-generation intelligent sensing devices. Among them, flexible mechanical sensors capable of measuring signals such as stress, strain, and pressure are crucial for constructing intelligent soft robots, wearable motion monitoring, and advanced human-computer interaction systems. However, current technological development still faces key challenges: many sensors struggle to simultaneously achieve high sensitivity and a wide linear response range, and their stability, reliability, and fatigue resistance under long-term cyclic use need improvement. Therefore, developing novel sensitive materials that combine excellent mechanical properties with stable electrical responses has become a core breakthrough driving progress in this field.

[0003] Natural cotton fibers, composed of twisted and entangled cellulose filaments, possess a hollow internal structure, high aspect ratio, and good elasticity, making them an ideal three-dimensional scaffold material for constructing multi-level sensing architectures. However, the controllable growth of secondary nanostructures on carbonized cotton substrates still faces challenges: traditional transition metal catalysts (such as Fe, Co, and Ni) are prone to sintering or carbon encapsulation during preparation, leading to catalyst deactivation and structural inhomogeneity, which can cause growth heterogeneity and form non-uniform conductive paths, thus limiting sensor performance. Therefore, developing new methods that can precisely control the growth of nanostructures and achieve multi-level ordered construction is of great significance for constructing high-performance multimodal sensing layers. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a carbon aerogel, a carbon aerogel-based elastomer, its preparation method, and its applications. The preparation method of this invention is simple and can transform waste into valuable resources, achieving high-value-added plastic recycling. The carbon aerogel-based elastomer, after encapsulation with an elastomer, exhibits a wide deformation range and near-linear electromechanical response characteristics, demonstrating high sensitivity in adhesion force detection and joint motion monitoring. It can reliably distinguish strain direction and amplitude while possessing a wide bidirectional strain range and high sensitivity, solving the trade-off between bidirectional strain range and sensitivity, and holds promise for applications in wearable electronic devices and human-machine interfaces.

[0005] This invention uses natural cotton fiber as a three-dimensional structural framework, and grows carbon nanofibers (Ni-S) in situ on the surface of biomass-derived elastic carbonized cotton fiber. x As an interface-controlled catalyst, waste plastics (polyolefins) are used as a sustainable carbon source. Through a one-step chemical vapor deposition process, a uniform hierarchical carbon structure is formed, and carbon nanofibers of nearly uniform length are grown in situ on the surface of carbonized cotton fibers, constructing a stretchable and compressible carbon nanofiber-carbonized cotton fiber aerogel. This method effectively suppresses the unevenness of catalyst coating and carbon deposition, and constructs a multi-level conductive network with a consistent structure.

[0006] The present invention solves the above-mentioned technical problems through the following technical solutions:

[0007] This invention provides a method for preparing carbon aerogel, which includes the following steps:

[0008] Cotton soaked in nickel salt solution was placed in the high-temperature zone of a dual-temperature zone tube furnace, while sulfur powder and polyolefin were placed in the low-temperature zone of the same furnace. The carbon aerogel was then obtained after heating.

[0009] In this invention, the nickel salt may include one or more of nickel sulfide, nickel nitrate, nickel chloride, and nickel sulfate, preferably including nickel sulfide and a water-soluble nickel salt, wherein the water-soluble nickel salt is one or more of nickel nitrate, nickel chloride, and nickel sulfate. The solvent in the nickel salt solution may be a solvent capable of dissolving the nickel salt, such as ethanol and / or deionized water. The concentration of the nickel salt solution may be 5 mM to 2 M, for example, 8 mM, 10 mM, 20 mM, 50 mM, 100 mM, 0.5 M, 1 M, or 2 M.

[0010] In this invention, the ratio of the molar amount of nickel in the nickel salt to the mass of the cotton can be (0.1 mmol-5 mol) / g, for example 0.2 mmol / g, 0.5 mmol / g, 1 mmol / g, 2 mmol / g, 5 mmol / g, 10 mmol / g, 20 mmol / g, 50 mmol / g, 0.1 mol / g, 0.5 mol / g, 1 mol / g, or 2 mol / g.

[0011] In this invention, the soaking time can be conventional in the art, generally sufficient to allow the nickel salt solution to be completely absorbed by the cotton. The method for preparing the cotton soaked in the nickel salt solution can also be conventional in the art, generally involving simply immersing the cotton in the nickel salt solution.

[0012] In some preferred embodiments, the concentration of the nickel salt solution is 5-200 mM, and the ratio of the molar amount of nickel in the nickel salt to the mass of the cotton is (0.1-50) mmol / g.

[0013] In one specific embodiment, the concentration of the nickel salt solution is 10 mM, and the ratio of the molar amount of nickel in the nickel salt to the mass of the cotton is 1 mmol / g.

[0014] In this invention, when the nickel salt includes nickel sulfide and water-soluble nickel salt, the nickel sulfide and water-soluble nickel salt can be immersed in cotton separately or simultaneously. The method for preparing cotton soaked in nickel salt solution preferably includes the following steps: first, immersing the cotton in water-soluble nickel salt solution, then adding sodium sulfide solution and / or thiourea solution, allowing it to stand at room temperature, and then drying it.

[0015] The solvents in the sodium sulfide solution and the thiourea solution can be conventional in the art, such as deionized water; the concentrations in the sodium sulfide solution and the thiourea solution can be 5 mM-1 M, for example 8 mM, 10 mM, 20 mM, 50 mM, 100 mM, 0.2 M, 0.5 M, 1 M, or 2 M. The molar ratio of sulfur in the sodium sulfide solution and / or the thiourea solution to nickel in the water-soluble nickel salt solution can be 1:(5-20), for example 1:8, 1:10, or 1:15.

[0016] When the nickel salt includes nickel sulfide and soluble nickel salt, the prepared carbon aerogel will have better performance.

[0017] In this invention, according to conventional practice, the cotton soaked in the nickel salt solution generally needs to be dried before heating. The drying is typically carried out in an oven; the drying temperature can be 60-120°C, for example 70°C, 80°C, or 100°C; and the drying time can be 6-24 hours, for example 12 hours.

[0018] In this invention, the molar ratio of nickel in the nickel salt to sulfur in the sulfur powder can be 1:(2-100), preferably 1:(5-30), for example 1:10, 1:15, 1:18, 1:18.8, 1:20, or 1:25. When the amount of sulfur is excessive, the catalyst Ni in the carbon aerogel... 0 Peak intensity weakens, Ni-S x The limited reducibility inhibits the growth of carbon nanofibers.

[0019] In this invention, the polyolefin is preferably polypropylene and / or polyethylene.

[0020] The melt index of the polypropylene can be 10-40 g / 10min, for example 35 g / 10min.

[0021] The melt index of the polyethylene can be 10-40 g / 10min, for example 25 g / 10min.

[0022] In this invention, the mass ratio of the cotton to the polyolefin can be 1:(2-20), for example 1:4, 1:6, 1:8, 1:10 or 1:15.

[0023] In this invention, the sulfur powder and the polyolefin are generally mixed before being placed into a tube furnace.

[0024] In this invention, the high-temperature zone temperature of the dual-temperature zone tube furnace is preferably 750-950℃, for example, 800℃, 820℃, 850℃, 880℃, or 900℃; the low-temperature zone temperature of the dual-temperature zone tube furnace is preferably 300-600℃, more preferably 350-550℃, for example, 380℃, 400℃, 420℃, 450℃, 480℃, 500℃, or 520℃; the heating holding time can be 1-6 hours, for example, 2 hours, 3 hours, or 4 hours; the heating rate to the high-temperature zone temperature can be 3-20℃ / min, for example, 5℃ / min, 10℃ / min, or 15℃ / min; the heating rate to the low-temperature zone temperature can be 3-20℃ / min, for example, 5℃ / min, 10℃ / min, or 15℃ / min. When the high-temperature zone temperature is low, carbon source cracking and Ni... 0 Insufficient reduction leads to a limited density of catalytic active sites, ultimately resulting in short and thin carbon nanofibers. When the temperature is too high, more complete reduction of Ni and rapid decomposition of carbon source will accelerate carbon dissolution and precipitation, causing a continuous carbon layer to form on the surface of cotton fibers, which inhibits the growth of one-dimensional carbon nanofibers.

[0025] In this invention, the dual-temperature zone tubular furnace typically consists of a gas supply unit and two independently heated quartz tubular reactors. According to conventional practice, after heating, the furnace generally needs to be naturally cooled to room temperature. According to conventional practice, the high-temperature zone and low-temperature zone of the dual-temperature zone tubular furnace can each be set with their own calcination temperature and heating rate, and both zones are heated simultaneously with the same holding time; generally, both the high-temperature zone and low-temperature zone of the dual-temperature zone tubular furnace can be heated to their respective target temperatures before holding. During the heating process, volatile substances in the low-temperature zone are typically transported from the low-temperature zone to the high-temperature zone by a carrier gas. During the reaction process, the reactants are generally placed in the central area of ​​the tubular furnace.

[0026] In this invention, the carrier gas used during the heating process is generally a mixture of inert gas and hydrogen.

[0027] The flow rate of the carrier gas can be 60-250 sccm, for example 80 sccm, 100 sccm, 115 sccm, 120 sccm, or 130 sccm. The flow rate of the inert gas can be 50-150 sccm, for example 60 sccm, 80 sccm, 100 sccm, 110 sccm, or 120 sccm. The flow rate of the hydrogen gas can be 5-50 sccm, for example 10 sccm, 15 sccm, 20 sccm, or 30 sccm.

[0028] The inert gas can be conventional in the art, such as argon. The flow rate ratio of the inert gas to the hydrogen can be 100:(5-30), for example, 100:10, 100:15 or 100:20.

[0029] In one specific implementation, the carrier gas is a mixture of 100 sccm argon and 15 sccm hydrogen.

[0030] In some preferred embodiments, the temperature of the high-temperature zone of the dual-temperature zone tube furnace is 800-900°C, the temperature of the low-temperature zone of the dual-temperature zone tube furnace is 350-550°C, and the heating holding time is 1-6 hours.

[0031] In one specific embodiment, the temperature of the high-temperature zone of the dual-temperature zone tube furnace is 850°C, the temperature of the low-temperature zone of the dual-temperature zone tube furnace is 400°C, 450°C or 500°C, and the heating holding time is 2 hours.

[0032] The present invention also provides a carbon aerogel prepared by the preparation method described above.

[0033] The present invention also provides a carbon aerogel having a carbonized cotton fiber skeleton, on which carbon nanofibers are uniformly distributed, and a nickel catalyst comprising Ni-S is present on top of the carbon nanofibers. x Components and Ni 0 .

[0034] In this invention, the top of the carbon nanofiber refers to the end that is not in contact with the carbonized cotton fiber.

[0035] In this invention, the carbon aerogel preferably has a foxtail grass-like hierarchical structure. That is, the middle core is carbonized cotton fiber, and carbon nanofibers are uniformly distributed on the core.

[0036] In this invention, the Ni-S x The composition preferably includes Ni3S2. Further, the Ni-S... x The components may also include Ni7S6.

[0037] In this invention, the carbonized cotton fiber skeleton is generally composed of twisted and entangled cellulose filaments, with a hollow internal structure. The aspect ratio of the carbonized cotton fibers in the carbonized cotton fiber skeleton can be conventional in the art; the average diameter can be 1-10 micrometers, for example 2 micrometers, 4 micrometers or 6 micrometers.

[0038] In this invention, the length of the carbon nanofiber can be 10-80 micrometers, for example 15 micrometers, 20 micrometers, 30 micrometers, 40 micrometers or 50 micrometers.

[0039] The present invention also provides a carbon aerogel-based elastomer, which includes the carbon aerogel as described above and silicone coated on the surface of the carbon aerogel.

[0040] In this invention, the silicone can be one or more of Dragon Skin silicone, Ecoflex, and PDMS. The thickness of the silicone can be conventional in the art, generally 1-15mm, for example 5mm, 8mm, or 10mm.

[0041] The present invention also provides a method for preparing a carbon aerogel-based elastomer as described above, which includes the following steps: casting silicone onto the surface of the carbon aerogel and heating and curing it at 60-120°C for 10-120 min.

[0042] In this invention, the silicone can be a conventional two-component silicone rubber. Components A and B of the silicone are generally flowable liquids; component A mainly consists of a catalyst (e.g., a platinum catalyst) and vinyl silicone oligomers, while component B mainly consists of a crosslinking agent and vinyl silicone oligomers; the two components need to be cured by heating after mixing; the mass ratio of component A to component B is, for example, 1:1.

[0043] In this invention, according to conventional practice in the art, the silicone generally needs to be vacuumed to remove air bubbles before use.

[0044] In this invention, according to the conventions of the art, the casting is generally carried out in a mold.

[0045] In this invention, after the pouring is completed, it is generally necessary to let it stand at room temperature for 6-20 hours, according to the conventions in the art.

[0046] In this invention, the heating and curing temperature is preferably 70-100°C, for example 80°C.

[0047] In this invention, the heating and curing time is preferably 10-60 min, for example 30 min.

[0048] The present invention also provides an application of the carbon aerogel-based elastomer as described above in the field of flexible electronics.

[0049] In this invention, the flexible electronics are preferably stretchable electrodes, flexible sensors, or electrophysiological sensors.

[0050] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0051] The reagents and raw materials used in this invention are all commercially available.

[0052] The positive and progressive effects of this invention are as follows:

[0053] The preparation method of this invention is simple and can turn waste into treasure, realizing the upgrading and recycling of high-value-added polyolefins; the carbon aerogel-based elastomer obtained by encapsulating the prepared carbon aerogel with elastomer exhibits a wide deformation range and near-linear electromechanical response characteristics, showing high sensitivity in adhesion force detection and joint motion monitoring; it can not only reliably distinguish the strain direction and amplitude, but also has a wide bidirectional strain range and high sensitivity, solving the trade-off problem between bidirectional strain range and sensitivity, and is expected to be applied in the fields of wearable electronic devices and human-machine interfaces. Attached Figure Description

[0054] Figure 1 SEM image of the carbon aerogel prepared in Example 1;

[0055] Figure 2 High-resolution SEM image of the carbon aerogel prepared in Example 1;

[0056] Figure 3 SEM image of the Ni-catalyzed carbon aerogel prepared in Comparative Example 1;

[0057] Figure 4 XRD patterns of the carbon aerogels prepared in Example 1 and Comparative Example 1;

[0058] Figure 5 The graphs show the tensile-recovery response of the carbon aerogel-based elastomer prepared from the carbon aerogel of Example 1 under tensile strain of 0-100% and the compression-recovery response under compressive strain of 0-40%.

[0059] Figure 6 The graph shows the signal reliability and repeatability of the carbon aerogel-based elastomer prepared from the carbon aerogel of Example 1 under cyclic tensile strain of 10%-60% at a fixed frequency of 0.1 Hz.

[0060] Figure 7 The graph shows the signal reliability and repeatability of the carbon aerogel-based elastomer prepared from the carbon aerogel of Example 1 under cyclic compression of 10%-30% at a fixed frequency of 0.1 Hz. Detailed Implementation

[0061] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0062] The cotton (degreased cotton) used in the following experiments was purchased from Shandong Dingtai Information Technology Co., Ltd.; the silicone DragonSkin 20 was purchased from SmoothOn; the polypropylene was purchased from Aladdin, melt index: 35g / 10min; the polyethylene was purchased from Aladdin, melt index: 25g / 10min (190℃ / 2.16kg); and the sulfur powder was purchased from Sinopharm Reagent. The dual-temperature zone tubular furnace consisted of a gas supply unit and two independently heated quartz tube reactors (inner diameter: 10cm).

[0063] Example 1

[0064] 1 g of degreased cotton was immersed in 100 mL of a 10 mM Ni(NO3)2 / ethanol solution. After complete absorption, the sample was dried at 70 °C for 12 hours to obtain Ni-exchange cotton fibers. The Ni-exchange cotton fibers were placed in the high-temperature zone of a dual-temperature tube furnace, while 0.6 g of sulfur powder and 8 g of polypropylene (PP) were placed in the low-temperature zone. Both zones were heated simultaneously. The high-temperature zone was heated at 10 °C / min. -1 The heating rate was increased to 850℃, while in the low-temperature region it was increased at a rate of 10℃·min. -1 The temperature was increased to 450℃ at a heating rate. The reaction was carried out in an Ar / H2 atmosphere (100 sccm / 15 sccm). After both regions reached the target temperature, they were held at that temperature for 2 hours. After cooling to room temperature, Ni-S was obtained. x Catalytic carbon aerogel.

[0065] Example 2

[0066] 1 g of degreased cotton was immersed in 100 mL of a 10 mM Ni(NO3)2 / ethanol solution. After complete absorption, the sample was dried at 70 °C for 12 hours to obtain Ni-exchange cotton fibers. The Ni-exchange cotton fibers were placed in the high-temperature zone of a dual-temperature tube furnace, while 0.6 g of sulfur powder and 8 g of polyethylene (PE) were placed in the low-temperature zone. The two zones were heated simultaneously. The high-temperature zone was heated at 10 °C / min. -1 The heating rate was increased to 850℃, while in the low-temperature region it was increased at a rate of 10℃·min. -1 The temperature was increased to 450℃ at a heating rate. The reaction was carried out in an Ar / H2 atmosphere (100 sccm / 15 sccm). After both regions reached the target temperature, they were held at that temperature for 2 hours. After cooling to room temperature, Ni-S was obtained. x Catalytic carbon aerogel.

[0067] Example 3

[0068] 1 g of degreased cotton was immersed in 100 mL of a 10 mM Ni(NO3)2 / ethanol solution. After complete absorption, the sample was dried at 70 °C for 12 hours to obtain Ni-exchange cotton fibers. The Ni-exchange cotton fibers were placed in the high-temperature zone of a dual-temperature tube furnace, while 0.6 g of sulfur powder and 8 g of polypropylene (PP) were placed in the low-temperature zone. Both zones were heated simultaneously. The high-temperature zone was heated at 10 °C / min. -1 The heating rate was increased to 850℃, while in the low-temperature region it was increased at a rate of 10℃·min. -1 The temperature was increased to 400℃ at a heating rate. The reaction was carried out in an Ar / H2 atmosphere (100 sccm / 15 sccm). After both regions reached the target temperature, they were held at that temperature for 2 hours. After cooling to room temperature, Ni-S was obtained. x Catalytic carbon aerogel.

[0069] Example 4

[0070] 1 g of degreased cotton was immersed in 100 mL of a 10 mM Ni(NO3)2 / ethanol solution. After complete absorption, the sample was dried at 70 °C for 12 hours to obtain Ni-exchange cotton fibers. The Ni-exchange cotton fibers were placed in the high-temperature zone of a dual-temperature tube furnace, while 0.6 g of sulfur powder and 8 g of polypropylene (PP) were placed in the low-temperature zone. Both zones were heated simultaneously. The high-temperature zone was heated at 10 °C / min. -1 The heating rate was increased to 850℃, while in the low-temperature region it was increased at a rate of 10℃·min. -1 The temperature was increased to 500℃ at a heating rate. The reaction was carried out in an Ar / H2 atmosphere (100 sccm / 15 sccm). After both regions reached the target temperature, they were held at that temperature for 2 hours. After cooling to room temperature, Ni-S was obtained. x Catalytic carbon aerogel.

[0071] Example 5

[0072] 1 g of degreased cotton was immersed in 100 mL of a 10 mM Ni(NO3)2 / ethanol solution, and then 10 mL of a 10 mM sodium sulfide aqueous solution was slowly added dropwise. After the solution was completely absorbed, the sample was allowed to stand at room temperature for 2 hours, and then dried at 100 °C for 12 hours to obtain Ni-exchange cotton fibers. The nickel-exchange cotton fibers were placed in the high-temperature zone of a dual-temperature zone tube furnace, while 0.6 g of sulfur powder and 8 g of polypropylene (PP) were placed in the low-temperature zone. The two zones were heated simultaneously. The high-temperature zone was heated at 10 °C / min. -1 The heating rate was increased to 850℃, while in the low-temperature region it was increased at a rate of 10℃·min. -1 The temperature was increased to 450℃ at a heating rate. The reaction was carried out in an Ar / H2 atmosphere (100 sccm / 15 sccm). After both regions reached the target temperature, they were held at that temperature for 2 hours. After cooling to room temperature, Ni-S was obtained. x Catalytic carbon aerogel.

[0073] Example 6

[0074] The carbon aerogels prepared in Examples 1-5 were cut into 10mm × 10mm × 10mm blocks and placed in a mold (15mm × 15mm × 20mm). Component A and component B of the silica gel were mixed at a mass ratio of 1:1 and poured onto the surface of the carbon aerogel blocks. The mold was then heated at 80°C for 30 minutes to obtain a Ni-S aerogel with a fully cured silica gel coating. x Catalytic carbon aerogel / silicone rubber (carbon aerogel-based elastomer).

[0075] Comparative Example 1

[0076] 0.5 g of degreased cotton was immersed in 50 mL of a 10 mM Ni(NO3)2 / ethanol solution. After complete absorption, the sample was dried at 60 °C for 12 hours to obtain Ni-exchange cotton fibers. The Ni-exchange cotton fibers were placed in the high-temperature zone of a dual-temperature tube furnace, while 4 g of polypropylene (PP) was placed in the low-temperature zone. Both zones were heated simultaneously. The high-temperature zone was heated at 10 °C / min. -1 The heating rate was increased to 850℃, while in the low-temperature region it was increased at a rate of 10℃·min. -1 The temperature was increased to 300℃ at a controlled heating rate, and then the low-temperature region was further heated to 450℃ to trigger the pyrolysis of PP and generate carbonaceous products. The reaction was carried out in an Ar / H2 atmosphere (100 sccm / 15 sccm) for 2 hours. After cooling to room temperature, Ni-catalyzed carbon aerogel composite material was obtained.

[0077] Effect Example

[0078] (1) Morphological and structural characterization

[0079] Figure 1 and Figure 2 The image shows an SEM image of the carbon aerogel prepared in Example 1. As can be seen from the image, the carbon nanofibers are uniformly distributed on the surface of the carbonized cotton fibers, without any obvious aggregation or local carbon deposition. The internal carbonized cotton fiber scaffold has a unidimensional high aspect ratio structure with an average diameter of about 4 micrometers. Figure 3 The image shows a SEM image of the Ni-catalyzed carbon aerogel prepared in Comparative Example 1. As can be seen from the image, there is a clear catalyst encapsulation phenomenon inside the carbon nanofibers, which leads to catalyst deactivation.

[0080] SEM analysis of the carbon aerogels prepared in Examples 1, 3, and 4 revealed that the catalysts maintained stable catalytic activity under different carbon source conditions and achieved controllable dissolution and precipitation of carbon on their surface. A uniform carbon nanofiber network structure continuously formed on the surface of the Ni3S2 catalyst.

[0081] Figure 4The XRD patterns of the carbon aerogels prepared in Example 1 and Comparative Example 1 are shown. According to the test results, the carbon aerogel prepared in Example 1 exhibits characteristic diffraction peaks of Ni3S2 and Ni... 0 The peak originates from the active metal Ni under a reducing carbon source. 0 The formation of [the structure]; while the carbon aerogel prepared in Comparative Example 1 was dominated by graphitic carbon signals, indicating that metallic Ni [was present]. 0 It plays a key role in the carbon precipitation and graphitization process.

[0082] Nitrogen adsorption-desorption tests showed that the carbon aerogel prepared in Example 1 exhibited a more hierarchical pore structure due to its uniformly distributed carbon nanofiber network and open framework, with pore sizes distributed in 10-12 Å, 12-15 Å and 15-19 Å.

[0083] (2) Stretchable electrode test and mechanical signal test

[0084] The carbon aerogel-based elastomer prepared from the carbon aerogels of Examples 1-5 was used as a stretchable mechanical sensor for strain-electrical performance testing: the two ends of the carbon aerogel-based elastomer were fixed in a tensile fixture, and liquid metal was used as the lead-out electrode to connect to copper foil. An electrochemical workstation was used as a signal acquisition device to collect and record electrical signals in real time.

[0085] according to Figure 5 It can be seen that the sensor prepared from the carbon aerogel in Example 1 exhibits a stable and reversible resistance response in the compressive strain range of 0-40% and the tensile strain range of 0-100%, indicating the controllable reconstruction and recovery capability of the conductive network during deformation, as well as good electromechanical properties over a wide strain range. This carbon aerogel-based elastomer sensor exhibits a strain coefficient GF of 7.9 at 82% tensile strain and GF of 1.7 at 28% compressive strain (Table 1). The device maintains stable performance even after undergoing more than 2000 tensile-compression cycles within a strain range of ±10%. Figure 6 and Figure 7 The cyclic testing results at different strain amplitudes show that the signal exhibits good repeatability and stability within the range of 10-30% compressive strain and 10-60% tensile strain. Furthermore, this carbon aerogel-based elastomer sensor can identify biological surfaces with different adhesion properties, such as apple peels, human skin, glutinous rice, and chewing gum. When integrated onto a finger, pressing and lifting a sticky object allows for simultaneous and accurate recording of the compressive response during pressing and the tensile response upon separation. Moreover, when used for human motion detection, the sensor outputs stable, periodic electrical signals, clearly reflecting the direction and amplitude of the movement.

[0086] Table 1. Strain coefficients of different embodiments at 82% tensile and 28% compressive strain.

[0087]

[0088] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A method for preparing carbon aerogel, characterized in that, Includes the following steps: Cotton soaked in nickel salt solution was placed in the high-temperature zone of a dual-temperature zone tube furnace, while sulfur powder and polyolefin were placed in the low-temperature zone of the same furnace. The carbon aerogel was then obtained after heating.

2. The method for preparing carbon aerogel as described in claim 1, characterized in that, The preparation method satisfies one or more of the following conditions: (1) The nickel salt includes one or more of nickel sulfide, nickel nitrate, nickel chloride and nickel sulfate, preferably including nickel sulfide and water-soluble nickel salt; (2) The solvent in the nickel salt solution is a solvent that can dissolve the nickel salt, such as ethanol and / or deionized water; (3) The concentration of the nickel salt solution is 5mM-2M, for example 8mM, 10mM, 20mM, 50mM, 100mM, 0.5M, 1M or 2M; (4) The ratio of the molar amount of nickel in the nickel salt to the mass of the cotton is (0.1 mmol - 5 mol) / g, for example 0.2 mmol / g, 0.5 mmol / g, 1 mmol / g, 2 mmol / g, 5 mmol / g, 10 mmol / g, 20 mmol / g, 50 mmol / g, 0.1 mol / g, 0.5 mol / g, 1 mol / g or 2 mol / g; (5) The molar ratio of nickel in the nickel salt to sulfur in the sulfur powder is 1:(2-100), preferably 1:(5-30), for example 1:10, 1:15, 1:18, 1:18.8, 1:20 or 1:25; (6) The polyolefin is polypropylene and / or polyethylene; (7) The mass ratio of the cotton to the polyolefin is 1:(2-20), for example 1:4, 1:6, 1:8, 1:10 or 1:

15.

3. The method for preparing carbon aerogel as described in claim 2, characterized in that, When the nickel salt includes nickel sulfide and water-soluble nickel salt, the preparation method of the cotton soaked in the nickel salt solution includes the following steps: first soaking the cotton in the water-soluble nickel salt solution, then adding sodium sulfide solution and / or thiourea solution, letting it stand at room temperature, and then drying it. Preferably, the concentrations of the sodium sulfide solution and the thiourea solution are 5 mM to 1 M; the molar ratio of sulfur in the sodium sulfide solution and / or the thiourea solution to nickel in the water-soluble nickel salt solution is preferably 1:(5-20).

4. The method for preparing carbon aerogel as described in claim 1, characterized in that, The high-temperature zone temperature of the dual-temperature zone tube furnace is 750-950℃, for example, 800℃, 820℃, 850℃, 880℃ or 900℃. And / or, the low-temperature zone temperature of the dual-temperature zone tube furnace is 300-600℃, preferably 350-550℃, for example 380℃, 400℃, 420℃, 450℃, 480℃, 500℃ or 520℃. And / or, the heating and heat preservation time is 1-6 hours, for example 2 hours, 3 hours or 4 hours.

5. The method for preparing carbon aerogel as described in claim 1, characterized in that, The concentration of the nickel salt solution is 5-200 mM, and the ratio of the molar amount of nickel in the nickel salt to the mass of the cotton is (0.1-50) mmol / g. And / or, the temperature of the high-temperature zone of the dual-temperature zone tube furnace is 800-900℃, the temperature of the low-temperature zone of the dual-temperature zone tube furnace is 350-550℃, and the heating holding time is 1-6h.

6. A carbon aerogel prepared by a method according to any one of claims 1-5.

7. A carbon aerogel, characterized in that, It has a carbonized cotton fiber skeleton, on the surface of which carbon nanofibers are uniformly distributed, and a nickel catalyst, comprising Ni-S, is present on top of the carbon nanofibers. x Components and Ni 0 ; Wherein, the Ni-S x The composition preferably includes Ni3S2; the average diameter of the carbonized cotton fibers in the carbonized cotton fiber skeleton is preferably 1-10 micrometers; and the length of the carbon nanofibers is preferably 10-80 micrometers.

8. A carbon aerogel-based elastomer, characterized in that, Includes the carbon aerogel as described in claim 6 or 7 and the silicone coating on the surface of the carbon aerogel.

9. A method for preparing a carbon aerogel-based elastomer as described in claim 8, characterized in that, The process includes the following steps: pouring silicone onto the surface of the carbon aerogel as described in claim 6 or 7, and heating and curing it at 60-120°C for 10-120 minutes.

10. An application of the carbon aerogel-based elastomer as described in claim 8 in the field of flexible electronics; The flexible electronics are preferably stretchable electrodes, flexible sensors, or electrophysiological sensors.

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