High-conductivity aerogel powder as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of aerogel, and particularly relates to high-conductivity aerogel powder as well as a preparation method and application thereof. The preparation method comprises the following steps: firstly preparing a graphene / polypyrrole nanosheet composite material with a three-dimensional structure, and then preparing the polyimide / graphene / polypyrrole ternary hybrid conductive aerogel by taking a polyamide acid solution as a precursor through a solution dipping and freeze drying process. Polyimide is used as a framework of high-conductivity aerogel powder, excellent mechanical strength and structural integrity are provided, the common brittleness problem of a pure graphene carbon material or polypyrrole conductive polymer aerogel is solved, and the three-dimensional graphene / polypyrrole nanosheet composite material has excellent elasticity and toughness and can be used for preparing a composite material with high conductivity. The polyimide aerogel prepared by the method can be dispersed in a polyimide matrix as a nano reinforcement, can effectively transfer stress and prevent crack propagation, and endows the aerogel with higher mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of aerogel technology, specifically relating to a highly conductive aerogel powder, its preparation method, and its application. Background Technology

[0002] Aerogels are a class of porous materials formed by replacing the liquid phase in a gel with gas. They are characterized by ultra-low density, high porosity, and high specific surface area. Aerogels are often referred to as "the lightest solid in the world" or "solid smoke." Their structure is mainly composed of a network of nanoscale particles filled with gas, giving them unique physicochemical properties.

[0003] Aerogels can be classified into the following categories based on their constituent materials, preparation methods, and applications: According to inorganic components, they can be divided into inorganic aerogels, such as silica aerogels and alumina aerogels; those with organic components are organic aerogels, such as polyamide aerogels and polyurethane aerogels; aerogels prepared by combining two or more materials are classified as composite aerogels. Furthermore, according to function, they can be broadly classified into thermal insulation aerogels, flexible sensing aerogels, adsorption aerogels, and optical aerogels. The material types of aerogels can be extended to include inorganic, organic, and composite aerogels.

[0004] Aerogels are applied in various fields due to their different material types and functions. In the field of thermal insulation, aerogels, with their low thermal conductivity, are widely used in building, spacecraft insulation, and pipeline insulation. In environmental remediation, the high specific surface area and adsorption capacity of aerogels make them suitable for water pollution control and air purification. Biomedical aerogels show great potential in areas such as drug delivery carriers and tissue engineering scaffolds. In defense and aerospace, aerogels can be used in bulletproof materials and high-performance aerospace insulation. Even with the numerous applications of aerogels, their industrial application is limited by the high cost of their preparation processes, such as the sol-gel method and supercritical drying, which require advanced technology. Their high porosity and low density also limit their application in certain scenarios due to brittle mechanical strength issues. Traditional aerogels are difficult to process into large-scale, complex shapes, affecting their practicality. The diverse needs of different fields require aerogels, and further research is needed to achieve multifunctionality while maintaining low-cost preparation. Furthermore, the preparation of some aerogels uses organic solvents and energy-intensive processes, highlighting the need for further development of green preparation technologies.

[0005] Conductive aerogels are a class of multifunctional materials that combine ultra-low density, high porosity, excellent conductivity, and mechanical flexibility. In recent years, they have attracted much attention in fields such as flexible electronics, energy storage, sensors, environmental purification, and personal thermal management. Their development has evolved from traditional inorganic aerogels to graphene aerogels, and then to multifunctional composite aerogels, and there is still broad room for future development. CN120988341A discloses a method for preparing a cellulose acetate / thermoplastic polyurethane / polypyrrole composite conductive nanofiber aerogel composite material. The preparation method includes: (1) preparation of cellulose acetate and thermoplastic polyurethane spinning solution; (2) preparation of cellulose acetate / thermoplastic polyurethane composite nanofiber membrane; (3) preparation of cellulose acetate / thermoplastic polyurethane short nano-dispersion; (4) preparation of cellulose acetate / thermoplastic polyurethane / polypyrrole polymerization solution; (5) preparation of cellulose acetate / thermoplastic polyurethane / polypyrrole composite conductive nanofiber aerogel. This preparation method does not require a high-temperature thermal annealing process, and the prepared nanofiber composite aerogel has high conductivity, ultra-low bulk density, and high compressive deformation performance. CN118223293A provides a conductive aerogel fiber, its preparation method, and its application. The preparation method includes the following steps: wet spinning an aramid nanofiber dispersion, supercritical drying, and chemical metal plating to obtain the conductive aerogel fiber; the wet spinning includes extruding the aramid nanofiber dispersion through a spinneret to form fibers, followed by coagulation in a coagulation bath to obtain gel fibers. The provided conductive aerogel fiber exhibits excellent thermal insulation and good flexibility. When connected to a power source with conductive silver paste, an applied 5V current can generate an electrothermal effect, making it suitable for warmth and protection in extremely cold weather. However, the conductive aerogels prepared by existing technologies have low mechanical strength and poor structural stability, limiting their further applications. Summary of the Invention

[0006] To address the technical problems of poor conductivity and low mechanical strength in existing aerogel materials, this invention provides a highly conductive aerogel powder and its preparation method. First, using graphene oxide as a substrate and copper quantum dots as auxiliary materials, a three-dimensional highly conductive composite material with polypyrrole and graphene as the matrix is ​​prepared. Then, it is blended with a polyimide precursor solution. The porous structure of the three-dimensional highly conductive composite material promotes the wetting of the polyimide precursor solution, maintaining the high conductivity of the composite material and improving its structural stability. This conductive aerogel not only possesses lightweight and low density characteristics but also exhibits high conductivity and high porosity.

[0007] To achieve the above objectives, the present invention provides the following solution: A method for preparing a highly conductive aerogel powder includes the following steps: (1) First, prepare a mixed dispersion of copper quantum dots / graphene oxide, then add an oxidant and stir until homogeneous to obtain a reaction solution; (2) Add pyrrole monomer to the reaction solution and react under ice-water bath (0℃) conditions to obtain graphene oxide / polypyrrole composite dispersion; (3) The graphene oxide / polypyrrole composite dispersion was reduced, filtered, washed and dried to obtain a three-dimensional graphene / polypyrrole nanosheet composite material; (4) The three-dimensional graphene / polypyrrole nanosheet composite material was added to a polyamic acid solution, and after sonication, a chemical imidizing agent was added to partially imidize it; it was allowed to stand, and then solvent exchange was performed with deionized water to prepare a hydrogel. (5) The hydrogel was freeze-dried, thermally imidized, and pulverized to obtain a highly conductive gas gel powder.

[0008] Currently, commonly used conductive aerogels are mainly carbon aerogels and conductive polymer aerogels. Carbon-based aerogels are mainly obtained by high-conductivity carbon nanomaterials such as carbon nanotubes and graphene, as well as porous biomass materials or polymer materials, after high-temperature carbonization. Their practical applications are limited by problems such as poor dispersibility, difficult processing, complex reduction, and insufficient stability. Conductive polymers are a class of organic polymers that acquire conductive functions by adding conductive fillers or by doping themselves. They can be divided into composite or structural conductive polymers. In addition to having high conductivity similar to metals, conductive polymers also possess the good flexibility and plasticity of polymers. However, conductive polymers usually have low overall mechanical properties, making them difficult to apply in high-stress fields. Therefore, this invention first uses graphene oxide as a substrate and copper quantum dots as an auxiliary material to prepare a three-dimensional highly conductive composite material with polypyrrole and graphene as the matrix. Then, it is blended with a polyimide precursor solution and freeze-dried to prepare a polyimide / graphene / polypyrrole ternary hybrid conductive aerogel. This hybrid conductive aerogel not only has a high specific surface area and low density, but also possesses enhanced mechanical properties, good flexibility, and excellent conductivity due to its three-dimensional structure formed by graphene and polypyrrole nanosheets.

[0009] As a common conductive polymer material, polypyrrole is often used as a conductive filler for thermoplastic resins such as polyolefins, imparting a certain degree of conductivity to the resin. However, its practical application faces a series of significant drawbacks. First, polypyrrole has a rigid chain structure, resulting in poor compatibility with the non-polar polyolefin matrix. It is prone to phase separation and agglomeration, leading to uneven dispersion and difficulty in forming a conductive network. Although existing technologies enhance the interfacial compatibility between polypyrrole and polyolefins by surface modification, such as introducing alkyl chains, using surfactants, or graft copolymerization, the preparation process is cumbersome, and the mixing process of polypyrrole and resin usually requires mechanical stirring. The modified polypyrrole has reduced mechanical properties and can easily damage the mechanical properties of the matrix resin. In particular, existing technologies generally directly add polypyrrole nanoparticles as conductive fillers. Rigid particles may act as stress concentration points, reducing the toughness, ductility, and other mechanical properties of polyolefins, leading to deterioration of mechanical properties.

[0010] To address the aforementioned issues, the inventors previously employed aramid nanofibers as a carrier for polypyrrole (CN120865606A, CN120867096A) to improve the mechanical stability of polypyrrole. However, aramid nanofibers lack electrical conductivity, offering limited improvement to the resin's conductivity. Unlike simple one-dimensional polypyrrole nanorods or two-dimensional graphene conductive materials, existing three-dimensional conductive materials generally possess a three-dimensional structure, forming macroscopic materials integrated from two-dimensional graphene sheets and conductive nanowires / nanorobars. While inheriting the excellent properties of two-dimensional graphene, such as thinness, high conductivity, superior mechanical strength, flexibility, and elasticity, their porous structure enhances their flexibility and specific surface area compared to traditional two-dimensional graphene, resulting in superior mass transfer performance. However, traditional graphene-based three-dimensional conductive materials are typically composed of one-dimensional nanowires or nanorods combined with two-dimensional graphene. They primarily rely on point-to-point or point-to-surface contact, leading to high contact resistance and fragile pathways. Moreover, the small contact area between one-dimensional conductive materials and graphene makes them prone to breakage during processing, shearing, or external force, requiring a higher filler load to form a conductive network, resulting in poor network stability.

[0011] This invention uses graphene oxide as a substrate and copper quantum dots as an auxiliary material to polymerize pyrrole monomers in situ on the graphene oxide surface to form nanosheet structures. After reduction, the graphene oxide forms a three-dimensional highly conductive composite material with polypyrrole and graphene as the matrix. The polypyrrole nanosheets are vertically distributed on the graphene surface, which not only increases the porosity and specific surface area of ​​the composite material but also improves the mechanical properties of the polypyrrole, facilitating the maintenance of stable polypyrrole morphology during machining. Compared to traditional three-dimensional conductive materials composed of graphene-nanorobars / nanowires, the graphene-polypyrrole nanosheet three-dimensional conductive material prepared by this invention can form a multi-faceted interconnected network with "face-to-face" and "edge-to-face" contacts. The sidewalls of the vertically arranged polypyrrole nanosheets easily contact each other, forming numerous conductive nodes. The wide interface between the polypyrrole nanosheet substrate and graphene results in low interfacial resistance, allowing for easier formation of efficient, low-percolation-threshold conductive pathways within the polymer matrix, leading to superior conductivity. Meanwhile, the graphene-polypyrrole nanosheet three-dimensional conductive material possesses a high specific surface area, providing numerous active interfaces for charge storage (for supercapacitors), molecular adsorption (for sensing), or interaction with the polymer matrix, thus enhancing the electrochemical activity of polypyrrole. Furthermore, the sheet-like structure of polypyrrole acts like a "nanolock," allowing for better interpenetration and entanglement with polymer molecular chains, resulting in stronger mechanical interlocking. This not only inhibits filler agglomeration but also effectively transfers stress, leading to better enhancement or retention of the composite material's mechanical properties (strength, toughness).

[0012] Specifically, this invention uses graphene oxide rich in oxygen-containing functional groups as a substrate because it exhibits good dispersibility in water and can adsorb copper quantum dots through hydrogen bonding and electrostatic interactions, laying the foundation for subsequent catalyst sites. On the other hand, copper quantum dots, as nanoscale metal particles, typically have a particle size below 10 nm. Their high surface energy tends to cause nanoparticles to aggregate into larger particles, which significantly reduces active sites and lowers catalytic efficiency. In contrast, the surface of graphene oxide sheets is rich in various oxygen-containing functional groups, allowing high-surface-energy copper quantum dots to be adsorbed onto the graphene oxide surface through electrostatic interactions, achieving atomic-level uniform distribution and effectively preventing leaching or migration and aggregation of copper quantum dots during use.

[0013] The inventors previously used copper quantum dots as a catalyst to prepare spherical polyacrylamide (CN119119360A, CN119176912A, CN119219836A, CN119219839A, etc.). The polymerization of pyrrole monomers is typically an oxidative polymerization process, requiring an oxidant to capture electrons from the pyrrole monomers, generating free radical cations, which then initiate chain growth. Copper quantum dots not only possess a large specific surface area and abundant active sites, but also exhibit excellent electron supply and acceptance capabilities. They can be uniformly anchored on graphene oxide sheets, becoming numerous and evenly distributed polymerization "nucleation centers." This ensures that polypyrrole can grow uniformly on the graphene oxide surface, rather than agglomerating into large particles, thus forming an ideal vertical nanosheet structure.

[0014] In the presence of an oxidant, high-surface-energy copper quantum dots can act as a "catalytic platform," enriching the oxidant and promoting the transfer of electrons from pyrrole monomers to the oxidant. This leads to a localized increase in reactant concentration, optimized reaction pathways, and a significant reduction in the activation energy of the polymerization reaction, allowing polymerization to proceed rapidly under milder conditions. Unlike traditional free radical initiators, copper quantum dots do not initiate pyrrole polymerization "alone," but through catalysis, they synergistically work with the main oxidant to efficiently catalyze the oxidative polymerization of pyrrole. Copper quantum dots act as nanoscale "seeds," guiding the in-situ polymerization and uniform growth of polypyrrole on the graphene oxide surface. Uniformly distributed on the graphene oxide sheets, copper quantum dots become the "nucleation centers" for pyrrole polymerization. Pyrrole monomers are first oxidized and polymerized into oligomers around the copper quantum dots. Subsequently, polymer chains radiate outward from the copper quantum dots, generating vertical nanosheet structures that tightly adhere to the graphene oxide sheets and ultimately embed into the graphene oxide surface. Through physicochemical interactions, these structures enhance the structural stability and conductivity of the composite material. After the polymerization reaction is complete, the oxygen-containing functional groups on the surface of graphene oxide are removed by a reduction process, and it is converted into reduced graphene oxide, thus obtaining a three-dimensional graphene / polypyrrole nanosheet composite material.

[0015] Graphene oxide serves not only as a stabilizer to prevent the aggregation and oxidation of copper quantum dots, but also as a nanoplatform guiding their uniform distribution and catalytic function, and ultimately as the structural foundation for constructing high-performance three-dimensional composite materials. This integrated "carrier-catalyst" design is key to obtaining highly conductive functional materials. In this way, the high activity of copper quantum dots is fully realized and maintained over time, while the excellent performance of graphene oxide / reduced graphene oxide is activated and enhanced by the introduction of copper quantum dots and polypyrrole.

[0016] Using polyimide as the matrix resin for highly conductive aerogel powder provides excellent processability as a precursor. Polyimide, as the final skeleton of the highly conductive aerogel powder, offers superior mechanical strength, thermal stability, and structural integrity, solving the common brittleness problem of pure graphene carbon materials or polypyrrole conductive polymer aerogels. The prepared three-dimensional graphene / polypyrrole nanosheet composite material itself possesses excellent elasticity and toughness. Dispersed within the polyimide matrix as a nano-reinforcement, it effectively transfers stress, prevents crack propagation, and imparts compressibility and resilience to the aerogel. The aerogel powder provided by this invention combines solution processing and freeze-drying processes, resulting in a relatively simple process that allows for the simultaneous construction of an organic polymer skeleton and an inorganic / organic hybrid conductive network in a one-step molding process.

[0017] In one embodiment, the specific process steps of step (1) are as follows: add copper quantum dots to graphene oxide dispersion, stir evenly to obtain mixed dispersion; add oxidant to mixed dispersion, stir evenly again to obtain reaction solution; In one embodiment, when adding copper quantum dots to the graphene oxide dispersion in step (1), the stirring rate is 300-500 rpm. Furthermore, the stirring time is 0.1-1 h. Stirring promotes the dispersion of copper quantum dots and graphene oxide, improving the degree of dispersion of the raw materials.

[0018] In one embodiment, the mass ratio of copper quantum dots to graphene oxide in step (1) is 0.1%-1%. Specifically, it can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%. In particular, it can be 0.1%-0.6% or 0.2%-0.4%. An appropriate amount of copper quantum dots can be uniformly dispersed on the surface of graphene oxide. Graphene oxide, as a carrier of copper quantum dots, can not only improve the stability of copper quantum dots, but also promote their dispersion and prevent them from agglomerating and annihilating.

[0019] In one embodiment, deionized water is used as the dispersion solvent for the graphene oxide dispersion in step (1). Further, the concentration of the graphene oxide dispersion is 0.5-10 mg / mL. Compared to graphene, graphene oxide contains a large number of oxygen-containing functional groups, is highly hydrophilic, and can be stably dispersed in solvents such as water and alcohol, facilitating solution processing and making it suitable for large-scale production. More importantly, the surface of graphene oxide sheets is rich in various oxygen-containing functional groups, allowing high-surface-energy copper quantum dots to be adsorbed onto the graphene oxide surface through electrostatic interactions, achieving atomic-level uniform distribution and improving the stability of the copper quantum dots.

[0020] In one embodiment, the oxidant in step (1) is one or more of ammonium persulfate, potassium persulfate, sodium bisulfite, and azobisisobutyronitrile. By adding the oxidant to the graphene oxide mixed dispersion loaded with copper quantum dots, it is beneficial for the oxidant to be adsorbed and enriched in advance. Subsequently, the added pyrrole monomer is preferentially oxidized around the copper quantum dots and polymerized into oligomers. Then, the polymer chains radiate outward from the copper quantum dots as the center to generate a vertical nanosheet structure.

[0021] In one embodiment, the stirring rate in step (1) is 300-500 rpm. Further, the stirring time is 0.1-1 h.

[0022] In one embodiment, the mass ratio of pyrrole monomer to graphene oxide in step (2) is (3-8):1. Specifically, the mass ratio of pyrrole monomer to graphene oxide is 3:1, 4:1, 5:1, 6:1, 7:1, or 8:1. In particular, the mass ratio of pyrrole monomer to graphene oxide is (4-6):1. An appropriate amount of pyrrole monomer can ensure the integrity of the sheet structure and avoid the phenomenon of excessive growth of nanosheets and mutual adhesion caused by excessive polypyrrole. The graphene oxide sheets serve as a flexible two-dimensional conductive framework, and the polypyrrole nanosheets serve as fillers and bridging components dispersed on the surface of the graphene oxide to construct an interpenetrating network structure, which greatly reduces the overall resistance.

[0023] In one embodiment, the mass ratio of the oxidant in step (1) to the pyrrole monomer in step (2) is (0.5-5):1. Specifically, it can be 0.5:1, 1:1, 2:1, 3:1, 4:1, or 5:1. In particular, the mass ratio of the oxidant in step (1) to the pyrrole monomer in step (2) is (1-3):1. If the amount of oxidant is too small, a large amount of pyrrole monomer cannot be oxidized, resulting in low reaction conversion rate and poor structural strength. If the amount of oxidant is too large, it may lead to over-oxidation of the polypyrrole backbone, producing defects such as carbonyl groups, destroying the conjugated structure, and thus reducing conductivity.

[0024] In one embodiment, the reaction time in step (2) is 8-12 hours. After the reaction begins, the pyrrole monomers polymerize and grow in situ, firmly "stitching" the originally easily stacked graphene oxide sheets together, which not only prevents the re-aggregation of graphene oxide, but also enhances the structural toughness.

[0025] In one embodiment, the reduction in step (3) is performed using a chemical reduction method. The reducing agent used for reduction is one or more of hydrazine hydrate, hydroiodic acid, ascorbic acid, and sodium borohydride. Compared to thermal reduction, chemical reduction using a reducing agent can restore the conductive network of graphene more efficiently and controllably under milder conditions without damaging the structure of the three-dimensional conductive network.

[0026] In one embodiment, the mass ratio of reducing agent to graphene oxide in step (3) is (0.5-10):1.

[0027] In one embodiment, the reduction temperature in step (3) is 80-90°C and the time is 3.5-6h.

[0028] In one embodiment, the washing in step (3) is performed by alternating washing with ethanol and deionized water, and the drying is performed by drying in a vacuum drying oven.

[0029] In one embodiment, the polyamic acid solution in step (4) is prepared by polymerizing dianhydride monomer and diamine monomer in an organic solvent.

[0030] In one embodiment, the molar ratio of dianhydride monomer to diamine monomer in step (4) is (1-1.04):1.

[0031] In one embodiment, the temperature of the polyamic acid preparation process in step (4) is 25-35°C and the time is 6-12h.

[0032] In one embodiment, the mass ratio of the sum of the dianhydride monomers and diamine monomers to the mass ratio of the three-dimensional graphene / polypyrrole nanosheet composite material in step (4) is (2-4):1. Specifically, it can be 2:1, 2.5:1, 3:1, 3.5:1, or 4:1. In particular, the mass ratio of the sum of the dianhydride monomers and diamine monomers to the mass ratio of the three-dimensional graphene / polypyrrole nanosheet composite material is (2.5-3.5):1. An appropriate amount of polyimide can achieve both conductivity and reinforcement effects, and the residual ions in the polyimide matrix can further improve the conductivity of the gel powder.

[0033] In one embodiment, the imidizing agent in step (4) is a mixture of acetic anhydride and pyridine in a molar ratio of (1-3):1, and the mass of the mixture is 1-4 times the sum of the masses of the dianhydride monomer and the diamine monomer. Specifically, the degree of partial imidization of the polyamic acid can be 20%-60%. Further, the partial imidization time is 2-5 hours.

[0034] In one embodiment, the diamine monomer in step (4) is p-phenylenediamine, 2-trifluoromethyl-1,4-diaminobenzene, 5-methyl-1,3-diaminobenzene, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-diamino-3,3'-bis(trifluoromethyl)diphenylmethane, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenylmethane, etc. One or more of the following: 4,4'-bis(4-aminophenoxy)benzene, 4,4'-bis(3-aminophenoxy)benzene, 4,4'-diamino-2,2'-bis(trifluoromethyl)biphenyl, 4,4'-diamino-2,2'-dimethylbiphenyl, 4,4'-diaminobiphenyl, 4,4'-diamino-3,3'-dimethylbiphenyl, 4,4'-diamino-3,3'-bis(trifluoromethyl)biphenyl, or 4,4'-bis(4-aminophenoxy)biphenyl.

[0035] In one embodiment, the dianhydride monomer in step (4) is pyromellitic dianhydride, oxydiphthalic anhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride, 2,3,3',4'-biphenyltetracarboxylic dianhydride, diphenyl sulfone-3,4,3',4'-tetracarboxylic dianhydride, 2,3,3',4'-benzophenone tetracarboxylic dianhydride, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)methane dianhydride, 2,2-bis(3,4-dicarboxyphenyl)propane dianhydride, 2,2'-bis(3,4-dicarboxyphenyl)propane dianhydride, etc. One or more of the following: (4-dicarboxylic acid) hexafluoropropane dianhydride, m-terphenyl-3,4,3',4'-tetracarboxylic dianhydride, p-terphenyl-3,4,3',4'-tetracarboxylic dianhydride, 1,3-bis(3,4-dicarboxyphenoxy)phenyl dianhydride, 1,4-bis(3,4-dicarboxyphenoxy)biphenyl dianhydride, 2,2-bis[(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, and 1,4,5,8-naphthalenetetracarboxylic dianhydride.

[0036] In one embodiment, the organic solvent in step (4) is one or more of N,N-dimethylacetamide, acetone, acetonitrile, dimethyl sulfoxide, N,N-dimethylformamide, and N-methylpyrrolidone.

[0037] In one embodiment, the thermal imidization temperature in step (4) is 150-200°C and the time is 2-6 hours.

[0038] On the other hand, this invention also provides applications of highly conductive aerogel powder in the preparation of battery materials, sensor materials, capacitor materials, detector materials, conductive sheets, conductive pipes, and grouting materials. The highly conductive aerogel powder not only possesses excellent electrical conductivity but also a rich porous structure, making it widely applicable in the field of high conductivity technology. Specifically, two-dimensional graphene sheets and vertically grown polypyrrole nanosheets together construct a three-dimensional interpenetrating network. This structure facilitates the formation of efficient conductive pathways with low filler content compared to single graphene sheets or polypyrrole nanosheets. Polypyrrole adheres tightly to the graphene surface through in-situ polymerization, reducing interfacial contact resistance. Overall, graphene provides high conductivity and excellent mechanical properties, while polypyrrole provides good electrochemical activity and easily tunable surface morphology. By constructing a three-dimensional hierarchical conductive network, the transformation of polymers from insulators to conductors or semiconductors can be achieved with extremely low filler loadings, while maintaining good processability and mechanical properties.

[0039] The aerogel powder prepared by this invention has wide applications and can be used as a conductive reinforcing filler to improve the relevant properties of composite materials, and is widely used in battery materials, capacitors and other fields. Compared with directly using three-dimensional graphene / polypyrrole nanosheet composites as conductive reinforcing fillers for polyolefin resins, using aerogel powder as a conductive reinforcing filler has superior performance. Moreover, polyimide, as a polar resin and due to its hygroscopic nature, has a higher conductivity than polyolefins. When using three-dimensional graphene / polypyrrole nanosheet composites directly, due to compatibility and processing stability issues, it is randomly dispersed in the polyolefin melt, requiring a high filler content to allow it to contact and overlap with each other in the matrix to accidentally form conductive pathways. High filler content leads to increased cost, deteriorated processing fluidity, and brittleness of the composite material. However, after being prepared into aerogel, each aerogel powder particle itself is a complete, continuous, three-dimensional interconnected conductive network. When these conductive networks are dispersed in polyolefins, conductivity no longer depends on accidental contact between sheets, but on the contact between the entire conductive filler. Because each particle is highly conductive, a complete conductive network can be constructed within the polyolefin matrix with only a low particle size, significantly reducing the percolation threshold. Specifically, regarding mechanical properties, graphene, as an inorganic material, is prone to agglomeration in the polymer matrix when directly used in three-dimensional graphene / polypyrrole nanosheet composites, becoming stress concentration points and impairing mechanical properties. However, in aerogel powders, the three-dimensional graphene / polypyrrole nanosheet composite is in-situ fixed and separated by the polyimide framework, forming a stable three-dimensional structure. During blending, it is necessary to disperse aerogel particles with good strength and toughness, rather than the more brittle three-dimensional graphene / polypyrrole nanosheet composite, effectively avoiding the breakage and agglomeration of the three-dimensional graphene / polypyrrole nanosheet composite. Overall, the polyimide framework in the aerogel powder encapsulates and fixes brittle graphene and polypyrrole in its three-dimensional network, which not only improves the solvent resistance and aging resistance of polypyrrole, but also provides physical protection for the conductive pathway, making the composite material more stable in conductivity and mechanical properties and slower in decay during repeated deformation, friction or long-term use.

[0040] Furthermore, this invention provides a polyolefin composite material comprising the following components in parts by weight: 50-150 parts polyolefin resin, 10-50 parts highly conductive aerogel powder, and 1-10 parts processing aids. This polyolefin composite material exhibits high mechanical strength and high electrical conductivity, and can be applied in fields such as battery current collectors, packaging films, sensors, electromagnetic shielding materials, and conductive materials, showing broad application prospects. The type of raw material for the composite material is not particularly limited. Specifically, this invention uses recycled polyolefins as the base material to reduce costs. Processing aids may include lubricants, antioxidants, flow modifiers, light stabilizers, UV absorbers, coupling agents, colorants, heat stabilizers, and anti-hydrolysis agents. The polyolefin may include common types such as polyethylene, polypropylene, polystyrene, ethylene-vinyl alcohol copolymers, and ethylene-vinyl acetate copolymers. In particular, the raw materials used in this invention are all common types and can be prepared, purchased, or recycled materials. For example, Maoming Petrochemical T30S can be selected for polypropylene, and BASF antioxidant 1010 can be selected for antioxidants.

[0041] Beneficial effects: (1) In this invention, a three-dimensional highly conductive composite material based on polypyrrole and graphene was first prepared using graphene oxide as a substrate and copper quantum dots as an auxiliary material. Then, it was blended with a polyimide precursor solution and freeze-dried to prepare a polyimide / graphene / polypyrrole ternary hybrid conductive aerogel. This hybrid conductive aerogel not only has a high specific surface area and low density, but also possesses enhanced mechanical properties, good flexibility, and excellent conductivity due to the three-dimensional structure formed by graphene and polypyrrole nanosheets.

[0042] (2) Copper quantum dots supported on graphene oxide provide a “micro-reaction platform” for the polymerization of pyrrole monomers. Pyrrole monomers can be enriched around copper quantum dots, achieving high concentrations locally and greatly improving catalytic efficiency. Graphene oxide sheets themselves are ideal frameworks for constructing three-dimensional networks. After being loaded with copper quantum dots, they become the core of structure guidance in subsequent polymerization, ultimately forming a stable three-dimensional conductive composite material with graphene as the framework and polypyrrole as the connection points.

[0043] (3) The polyimide framework in the aerogel powder encapsulates and fixes the brittle graphene and polypyrrole in its three-dimensional network, which not only improves the solvent resistance and anti-aging properties of polypyrrole, but also provides physical protection for the conductive pathway, making the conductive and mechanical properties of the composite material more stable and slower to decay during repeated deformation, friction or long-term use.

[0044] (4) By constructing a three-dimensional hierarchical conductive network, the transformation of polyolefin resins from insulators to conductors or semiconductors can be achieved under a lower filler load, while maintaining good processability and mechanical properties. Using this highly conductive aerogel powder as a conductive filler for the resin further improves its conductivity while maintaining the high mechanical properties of the resin, thus solving the technical problem of reduced mechanical properties of composite materials caused by the addition of ordinary conductive fillers. Attached Figure Description

[0045] Figure 1 and Figure 2 The images shown are transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images of the three-dimensional graphene / polypyrrole nanosheet composite material prepared in Example 11.

[0046] Figure 3 The image shows a scanning electron microscope (SEM) image of the highly conductive aerogel powder prepared in Example 11.

[0047] Figure 4 and Figure 5 The images shown are transmission electron microscope (TEM) and scanning electron microscope (SEM) images of the graphene / polypyrrole composite material prepared in Comparative Example 1.

[0048] Figure 6 The image shows a scanning electron microscope (SEM) image of the aerogel powder prepared in Comparative Example 1. Detailed Implementation

[0049] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application. Unless otherwise specified, the raw material types of the following embodiments and comparative examples are the same.

[0050] Performance Testing: A polypropylene composite material comprising the following components by weight: 100 parts polypropylene resin, 30 parts aerogel powder (prepared in Examples 1-11 and Comparative Examples 1-2, respectively), 2 parts antioxidant 1010, and 2 parts polyethylene wax lubricant. The above components were added to a twin-screw extruder and melt-extruded into granules (extruder temperature 190°C). Standard samples were then prepared, and their mechanical and electrical properties were tested. Tensile strength was measured according to ASTM D638, flexural strength according to ASTM D790, and the volume resistivity of the samples was measured using a ohmmeter.

[0051] Example 1 A method for preparing a highly conductive aerogel powder includes the following steps: (1) Add copper quantum dots to a deionized water dispersion of graphene oxide and stir at 300 rpm for 0.5 h to obtain a mixed dispersion; the mass ratio of copper quantum dots to graphene oxide is 0.1%; the concentration of the deionized water dispersion of graphene oxide is 0.8 mg / mL; add ammonium persulfate as an oxidant to the mixed dispersion and stir at 300 rpm for 0.5 h to obtain a reaction solution; the mass ratio of oxidant to pyrrole monomer is 2.7:1. (2) Add pyrrole monomer to the reaction solution and react for 8 hours under ice-water bath (0℃) conditions to obtain graphene oxide / polypyrrole composite dispersion; the mass ratio of pyrrole monomer to graphene oxide is 3:1; (3) Add ascorbic acid as a reducing agent to the graphene oxide / polypyrrole composite dispersion, react at 80°C for 6 hours, filter, wash alternately with ethanol and deionized water, and dry in a vacuum drying oven to obtain the three-dimensional graphene / polypyrrole nanosheet composite material; the mass ratio of reducing agent to graphene oxide is 1:1. (4) The dianhydride monomer and diamine monomer were dispersed in the organic solvent N,N-dimethylacetamide and reacted at 30°C for 8 h to obtain a polyamic acid solution. Three-dimensional graphene / polypyrrole nanosheet composite material was added to the polyamic acid solution and ultrasonically dispersed until uniform. Then, an imidizing agent was added and reacted for 3 h to perform partial imidization. After standing, a hydrogel was prepared by solvent exchange with deionized water. The molar ratio of the dianhydride monomer to the diamine monomer was 1.02:1. The sum of the masses of the dianhydride monomer and the diamine monomer was equal to the mass of the three-dimensional graphene / polypyrrole nanosheet composite material. The mass ratio of the composite materials is 2:1; the mass ratio of the sum of the dianhydride monomers and the diamine monomers to the organic solvent is 4 wt%; the dianhydride monomers are a mixture of pyromellitic dianhydride and 3,3',4,4'-biphenyltetracarboxylic dianhydride in a molar ratio of 3:1; the diamine monomers are a mixture of 4,4'-diaminodiphenyl ether and 4,4'-diaminodiphenylmethane in a molar ratio of 1:1; the imidizing agent is a mixture of acetic anhydride and pyridine in a molar ratio of 2:1, and the mass of the mixture is 1.7 times the sum of the masses of the dianhydride monomers and the diamine monomers.

[0052] (5) The hydrogel was freeze-dried and then subjected to thermal imidization at 160℃ / 1h and 180℃ / 2h. After pulverization, a highly conductive aerogel powder was obtained. The corresponding polypropylene composite material was tested and found to have a tensile strength of 39.8 MPa, a flexural strength of 48.7 MPa, and a volume resistivity of 8.2 × 10⁻⁶. 6 Ω·m.

[0053] Example 2 A method for preparing a highly conductive aerogel powder includes the following steps: (1) Add copper quantum dots to a deionized water dispersion of graphene oxide and stir at 500 rpm for 0.5 h to obtain a mixed dispersion; the mass ratio of copper quantum dots to graphene oxide is 0.5%; the concentration of the deionized water dispersion of graphene oxide is 2.2 mg / mL; add ammonium persulfate as an oxidant to the mixed dispersion and stir at 500 rpm for 0.5 h to obtain a reaction solution; the mass ratio of oxidant to pyrrole monomer is 3.4:1. (2) Add pyrrole monomer to the reaction solution and react for 12 h in an ice-water bath (0℃) to obtain graphene oxide / polypyrrole composite dispersion; the mass ratio of pyrrole monomer to graphene oxide is 7.5:1; (3) Add ascorbic acid as a reducing agent to the graphene oxide / polypyrrole composite dispersion, react at 90°C for 3.5 h, filter, wash alternately with ethanol and deionized water, and dry in a vacuum drying oven to obtain the three-dimensional graphene / polypyrrole nanosheet composite material; the mass ratio of reducing agent to graphene oxide is 4:1. (4) The dianhydride monomer and diamine monomer were dispersed in the organic solvent N,N-dimethylacetamide and reacted at 30°C for 8 h to obtain a polyamic acid solution. A three-dimensional graphene / polypyrrole nanosheet composite material was added to the polyamic acid solution and ultrasonically dispersed until uniform. Then, an imidizing agent was added and reacted for 3 h to perform partial imidization. After standing, a hydrogel was prepared by solvent exchange with deionized water. The molar ratio of the dianhydride monomer to the diamine monomer was 1.02:1. The sum of the masses of the dianhydride monomer and the diamine monomer, along with the three-dimensional graphene / polypyrrole nanosheet composite material, was... The mass ratio of the materials is 3.5:1; the mass ratio of the sum of the dianhydride monomers and the diamine monomers to the organic solvent is 4 wt%; the dianhydride monomer is a mixture of pyromellitic dianhydride and 3,3',4,4'-benzophenone tetracarboxylic dianhydride in a molar ratio of 1:1; the diamine monomer is a mixture of 4,4'-diaminodiphenyl ether and 3,3'-diaminobenzophenone in a molar ratio of 2:1; the imidizing agent is a mixture of acetic anhydride and pyridine in a molar ratio of 2:1, and the mass of the mixture is 2.2 times the sum of the masses of the dianhydride monomers and the diamine monomers.

[0054] (5) The hydrogel was freeze-dried and then subjected to thermal imidization at 160℃ / 1h and 180℃ / 2h. After pulverization, a highly conductive aerogel powder was obtained. The corresponding polypropylene composite material was tested and found to have a tensile strength of 41.4 MPa, a flexural strength of 50.2 MPa, and a volume resistivity of 5.3 × 10⁻⁶. 7 Ω·m.

[0055] Example 3 A method for preparing a highly conductive aerogel powder includes the following steps: (1) Add copper quantum dots to a deionized water dispersion of graphene oxide and stir at 400 rpm for 0.5 h to obtain a mixed dispersion; the mass ratio of copper quantum dots to graphene oxide is 0.38%; the concentration of the deionized water dispersion of graphene oxide is 1.5 mg / mL; add ammonium persulfate as an oxidant to the mixed dispersion and stir at 400 rpm for 0.5 h to obtain a reaction solution; the mass ratio of oxidant to pyrrole monomer is 3:1. (2) Add pyrrole monomer to the reaction solution and react for 10 h in an ice-water bath (0℃) to obtain graphene oxide / polypyrrole composite dispersion; the mass ratio of pyrrole monomer to graphene oxide is 5:1; (3) Add ascorbic acid as a reducing agent to the graphene oxide / polypyrrole composite dispersion, react at 85°C for 4.5 h, filter, wash alternately with ethanol and deionized water, and dry in a vacuum drying oven to obtain the three-dimensional graphene / polypyrrole nanosheet composite material; the mass ratio of reducing agent to graphene oxide is 2:1. (4) The dianhydride monomer and diamine monomer were dispersed in the organic solvent N,N-dimethylacetamide and reacted at 30°C for 8 h to obtain a polyamic acid solution. The three-dimensional graphene / polypyrrole nanosheet composite material was added to the polyamic acid solution and ultrasonically dispersed evenly. Then, an imidizing agent was added and reacted for 3 h to perform partial imidization. After standing, a hydrogel was prepared by solvent exchange with deionized water. The molar ratio of the dianhydride monomer to the diamine monomer was 1.02:1. The ratio of the sum of the masses of the dianhydride monomer and the diamine monomer to the mass of the three-dimensional graphene / polypyrrole nanosheet composite material was... The ratio of the dianhydride monomer to the diamine monomer is 4:1; the mass ratio of the sum of the masses of the dianhydride monomer and the diamine monomer to the mass of the organic solvent is 4 wt%; the dianhydride monomer is a mixture of 3,3',4,4'-benzophenone tetracarboxylic dianhydride and 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride in a molar ratio of 1:2; the diamine monomer is a mixture of 4,4'-diaminobenzophenone and 4,4'-diaminodiphenyl sulfone in a molar ratio of 2:1; the imidizing agent is a mixture of acetic anhydride and pyridine in a molar ratio of 2:1, and the mass of the mixture is 2.1 times the sum of the masses of the dianhydride monomer and the diamine monomer.

[0056] (5) The hydrogel was freeze-dried and then subjected to thermal imidization at 160℃ / 1h and 180℃ / 2h. After pulverization, a highly conductive aerogel powder was obtained. The corresponding polypropylene composite material was tested and found to have a tensile strength of 42.1 MPa, a flexural strength of 52.3 MPa, and a volume resistivity of 8.5 × 10⁻⁶. 7 Ω·m.

[0057] Example 4 A method for preparing a highly conductive aerogel powder includes the following steps: (1) Add copper quantum dots to a deionized water dispersion of graphene oxide and stir at 350 rpm for 0.5 h to obtain a mixed dispersion; the mass ratio of copper quantum dots to graphene oxide is 0.15%; the concentration of the deionized water dispersion of graphene oxide is 2.1 mg / mL; add ammonium persulfate as an oxidant to the mixed dispersion and stir at 450 rpm for 0.5 h to obtain a reaction solution; the mass ratio of oxidant to pyrrole monomer is 3.3:1. (2) Add pyrrole monomer to the reaction solution and react for 9 h in an ice-water bath (0℃) to obtain graphene oxide / polypyrrole composite dispersion; the mass ratio of pyrrole monomer to graphene oxide is 6.5:1; (3) Add ascorbic acid as a reducing agent to the graphene oxide / polypyrrole composite dispersion, react at 80°C for 3.5 h, filter, wash alternately with ethanol and deionized water, and dry in a vacuum drying oven to obtain the three-dimensional graphene / polypyrrole nanosheet composite material; the mass ratio of reducing agent to graphene oxide is 2.5:1. (4) The dianhydride monomer and diamine monomer were dispersed in the organic solvent N,N-dimethylacetamide and reacted at 30°C for 8 h to obtain a polyamic acid solution. The three-dimensional graphene / polypyrrole nanosheet composite material was added to the polyamic acid solution and ultrasonically dispersed evenly. Then, an imidizing agent was added and reacted for 3 h to perform partial imidization. After standing, a hydrogel was prepared by solvent exchange with deionized water. The molar ratio of the dianhydride monomer to the diamine monomer was 1.02:1. The ratio of the sum of the masses of the dianhydride monomer and the diamine monomer to the mass of the three-dimensional graphene / polypyrrole nanosheet composite material was... The ratio of the dianhydride monomer to the diamine monomer is 2.2:1; the mass ratio of the sum of the masses of the dianhydride monomer and the diamine monomer to the organic solvent is 4 wt%; the dianhydride monomer is a mixture of 3,3',4,4'-biphenyltetracarboxylic dianhydride and 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride in a molar ratio of 1:3; the diamine monomer is a mixture of 4,4'-diaminodiphenyl ether and 4,4'-diaminodiphenyl sulfone in a molar ratio of 1:1; the imidizing agent is a mixture of acetic anhydride and pyridine in a molar ratio of 2:1, and the mass of the mixture is 1.8 times the sum of the masses of the dianhydride monomer and the diamine monomer.

[0058] (5) The hydrogel was freeze-dried and then subjected to thermal imidization at 160℃ / 1h and 180℃ / 2h. After pulverization, a highly conductive aerogel powder was obtained. The corresponding polypropylene composite material was tested and found to have a tensile strength of 41.2 MPa, a flexural strength of 50.8 MPa, and a volume resistivity of 1.7 × 10⁻⁶. 7 Ω·m.

[0059] Example 5 A method for preparing a highly conductive aerogel powder includes the following steps: (1) Add copper quantum dots to a deionized water dispersion of graphene oxide and stir at 400 rpm for 0.5 h to obtain a mixed dispersion; the mass ratio of copper quantum dots to graphene oxide is 0.6%; the concentration of the deionized water dispersion of graphene oxide is 1.5 mg / mL; add ammonium persulfate as an oxidant to the mixed dispersion and stir at 400 rpm for 0.5 h to obtain a reaction solution; the mass ratio of oxidant to pyrrole monomer is 3:1. (2) Add pyrrole monomer to the reaction solution and react for 10 h in an ice-water bath (0℃) to obtain graphene oxide / polypyrrole composite dispersion; the mass ratio of pyrrole monomer to graphene oxide is 5:1; (3) Add ascorbic acid as a reducing agent to the graphene oxide / polypyrrole composite dispersion, react at 85°C for 4.5 h, filter, wash alternately with ethanol and deionized water, and dry in a vacuum drying oven to obtain the three-dimensional graphene / polypyrrole nanosheet composite material; the mass ratio of reducing agent to graphene oxide is 2:1. (4) The dianhydride monomer and diamine monomer were dispersed in the organic solvent N,N-dimethylacetamide and reacted at 30°C for 8 hours to obtain a polyamic acid solution. A three-dimensional graphene / polypyrrole nanosheet composite material was added to the polyamic acid solution and ultrasonically dispersed until uniform. Then, an imidizing agent was added and reacted for 3 hours to perform partial imidization. After standing, a hydrogel was prepared by solvent exchange with deionized water. The molar ratio of the dianhydride monomer to the diamine monomer was 1.02:1. The mass ratio of the sum of the dianhydride monomer and the diamine monomer to the mass of the three-dimensional graphene / polypyrrole nanosheet composite material was... 2.8:1; the mass ratio of the sum of the dianhydride monomers and the diamine monomers to the organic solvent is 4 wt%; the dianhydride monomer is a mixture of 3,3',4,4'-benzophenone tetracarboxylic dianhydride and 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride in a molar ratio of 1:2; the diamine monomer is a mixture of 4,4'-diaminobenzophenone and 4,4'-diaminodiphenyl sulfone in a molar ratio of 2:1; the imidizing agent is a mixture of acetic anhydride and pyridine in a molar ratio of 2:1, and the mass of the mixture is 2.1 times the sum of the masses of the dianhydride monomers and the diamine monomers.

[0060] (5) The hydrogel was freeze-dried and then subjected to thermal imidization at 160℃ / 1h and 180℃ / 2h. After pulverization, a highly conductive aerogel powder was obtained. The corresponding polypropylene composite material was tested and found to have a tensile strength of 40.7 MPa, a flexural strength of 51.5 MPa, and a volume resistivity of 6.4 × 10⁻⁶. 7 Ω·m.

[0061] Example 6 A method for preparing a highly conductive aerogel powder includes the following steps: (1) Add copper quantum dots to a deionized water dispersion of graphene oxide and stir at 360 rpm for 0.5 h to obtain a mixed dispersion; the mass ratio of copper quantum dots to graphene oxide is 0.25%; the concentration of the deionized water dispersion of graphene oxide is 1.2 mg / mL; add ammonium persulfate as an oxidant to the mixed dispersion and stir at 380 rpm for 0.5 h to obtain a reaction solution; the mass ratio of oxidant to pyrrole monomer is 2.9:1. (2) Add pyrrole monomer to the reaction solution and react for 9 h in an ice-water bath (0℃) to obtain graphene oxide / polypyrrole composite dispersion; the mass ratio of pyrrole monomer to graphene oxide is 4.5:1; (3) Add ascorbic acid as a reducing agent to the graphene oxide / polypyrrole composite dispersion, react at 83°C for 5.2 h, filter, wash alternately with ethanol and deionized water, and dry in a vacuum drying oven to obtain the three-dimensional graphene / polypyrrole nanosheet composite material; the mass ratio of reducing agent to graphene oxide is 1.5:1; (4) The dianhydride monomer and diamine monomer were dispersed in the organic solvent N,N-dimethylacetamide and reacted at 30°C for 8 h to obtain a polyamic acid solution. Three-dimensional graphene / polypyrrole nanosheet composite material was added to the polyamic acid solution and ultrasonically dispersed until uniform. Then, an imidizing agent was added and reacted for 3 h to perform partial imidization. After standing, a hydrogel was prepared by solvent exchange with deionized water. The molar ratio of the dianhydride monomer to the diamine monomer was 1.02:1. The sum of the masses of the dianhydride monomer and the diamine monomer was equal to the mass of the three-dimensional graphene / polypyrrole nanosheet composite material. The mass ratio is 3:1; the mass ratio of the sum of the dianhydride monomers and the diamine monomers to the organic solvent is 4 wt%; the dianhydride monomers are a mixture of 3,3',4,4'-biphenyltetracarboxylic dianhydride and 3,3',4,4'-benzophenonetetracarboxylic dianhydride in a molar ratio of 2:1; the diamine monomers are a mixture of 4,4'-diaminodiphenylmethane and 4,4'-diaminodiphenyl sulfone in a molar ratio of 1:3; the imidizing agent is a mixture of acetic anhydride and pyridine in a molar ratio of 2:1, and the mass of the mixture is twice the sum of the masses of the dianhydride monomers and the diamine monomers.

[0062] (5) The hydrogel was freeze-dried and then subjected to thermal imidization at 160℃ / 1h and 180℃ / 2h. After pulverization, a highly conductive aerogel powder was obtained. The corresponding polypropylene composite material was tested and found to have a tensile strength of 40.3 MPa, a flexural strength of 49.8 MPa, and a volume resistivity of 9.3 × 10⁻⁶ MPa. 7 Ω·m.

[0063] Example 7 A method for preparing a highly conductive aerogel powder includes the following steps: (1) Add copper quantum dots to a deionized water dispersion of graphene oxide and stir at 400 rpm for 0.5 h to obtain a mixed dispersion; the mass ratio of copper quantum dots to graphene oxide is 0.38%; the concentration of the deionized water dispersion of graphene oxide is 1.5 mg / mL; add ammonium persulfate as an oxidant to the mixed dispersion and stir at 400 rpm for 0.5 h to obtain a reaction solution; the mass ratio of oxidant to pyrrole monomer is 3:1. (2) Add pyrrole monomer to the reaction solution and react for 10 h in an ice-water bath (0℃) to obtain graphene oxide / polypyrrole composite dispersion; the mass ratio of pyrrole monomer to graphene oxide is 8:1; (3) Add ascorbic acid as a reducing agent to the graphene oxide / polypyrrole composite dispersion, react at 85°C for 4.5 h, filter, wash alternately with ethanol and deionized water, and dry in a vacuum drying oven to obtain the three-dimensional graphene / polypyrrole nanosheet composite material; the mass ratio of reducing agent to graphene oxide is 2:1. (4) The dianhydride monomer and diamine monomer were dispersed in the organic solvent N,N-dimethylacetamide and reacted at 30°C for 8 hours to obtain a polyamic acid solution. A three-dimensional graphene / polypyrrole nanosheet composite material was added to the polyamic acid solution and ultrasonically dispersed until uniform. Then, an imidizing agent was added and reacted for 3 hours to perform partial imidization. After standing, a hydrogel was prepared by solvent exchange with deionized water. The molar ratio of the dianhydride monomer to the diamine monomer was 1.02:1. The mass ratio of the sum of the dianhydride monomer and the diamine monomer to the mass of the three-dimensional graphene / polypyrrole nanosheet composite material was... 2.8:1; the mass ratio of the sum of the dianhydride monomers and the diamine monomers to the organic solvent is 4 wt%; the dianhydride monomer is a mixture of 3,3',4,4'-benzophenone tetracarboxylic dianhydride and 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride in a molar ratio of 1:2; the diamine monomer is a mixture of 4,4'-diaminobenzophenone and 4,4'-diaminodiphenyl sulfone in a molar ratio of 2:1; the imidizing agent is a mixture of acetic anhydride and pyridine in a molar ratio of 2:1, and the mass of the mixture is 2.1 times the sum of the masses of the dianhydride monomers and the diamine monomers.

[0064] (5) The hydrogel was freeze-dried and then subjected to thermal imidization at 160℃ / 1h and 180℃ / 2h. After pulverization, a highly conductive aerogel powder was obtained. The corresponding polypropylene composite material was tested and found to have a tensile strength of 40.5 MPa, a flexural strength of 52.1 MPa, and a volume resistivity of 4.8 × 10⁻⁶. 7 Ω·m.

[0065] Example 8 A method for preparing a highly conductive aerogel powder includes the following steps: (1) Add copper quantum dots to a deionized water dispersion of graphene oxide and stir at 450 rpm for 0.5 h to obtain a mixed dispersion; the mass ratio of copper quantum dots to graphene oxide is 0.45%; the concentration of the deionized water dispersion of graphene oxide is 1.8 mg / mL; add ammonium persulfate as an oxidant to the mixed dispersion and stir at 450 rpm for 0.5 h to obtain a reaction solution; the mass ratio of oxidant to pyrrole monomer is 3.2:1. (2) Add pyrrole monomer to the reaction solution and react for 11 h in an ice-water bath (0℃) to obtain graphene oxide / polypyrrole composite dispersion; the mass ratio of pyrrole monomer to graphene oxide is 7:1; (3) Add ascorbic acid as a reducing agent to the graphene oxide / polypyrrole composite dispersion, react at 88°C for 4 hours, filter, wash alternately with ethanol and deionized water, and dry in a vacuum drying oven to obtain the three-dimensional graphene / polypyrrole nanosheet composite material; the mass ratio of reducing agent to graphene oxide is 3.5:1. (4) The dianhydride monomer and diamine monomer were dispersed in the organic solvent N,N-dimethylacetamide and reacted at 30°C for 8 h to obtain a polyamic acid solution. The three-dimensional graphene / polypyrrole nanosheet composite material was added to the polyamic acid solution and ultrasonically dispersed evenly. Then an imidizing agent was added and reacted for 3 h to perform partial imidization. After standing, the solution was exchanged with deionized water to prepare a hydrogel. The molar ratio of the dianhydride monomer to the diamine monomer was 1.02:1. The mass ratio of the sum of the dianhydride monomer and the diamine monomer to the mass of the three-dimensional graphene / polypyrrole nanosheet composite material was 3. The ratio of the total mass of the dianhydride monomer and the diamine monomer to the organic solvent is 2:1; the mass ratio of the sum of the masses of the dianhydride monomer and the diamine monomer to the organic solvent is 4 wt%; the dianhydride monomer is a mixture of 3,3',4,4'-benzophenone tetracarboxylic dianhydride and 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride in a molar ratio of 1.5:1; the diamine monomer is a mixture of 4,4'-diaminodiphenyl ether and 4,4'-diaminobenzophenone in a molar ratio of 1.5:1; the imidizing agent is a mixture of acetic anhydride and pyridine in a molar ratio of 2:1, and the mass of the mixture is 1.9 times the sum of the masses of the dianhydride monomer and the diamine monomer.

[0066] (5) The hydrogel was freeze-dried and then subjected to thermal imidization at 160℃ / 1h and 180℃ / 2h. After pulverization, a highly conductive aerogel powder was obtained. The corresponding polypropylene composite material was tested and found to have a tensile strength of 41.8 MPa, a flexural strength of 50.3 MPa, and a volume resistivity of 7.4 × 10⁻⁶ MPa. 7 Ω·m.

[0067] Example 9 A method for preparing a highly conductive aerogel powder includes the following steps: (1) Add copper quantum dots to a deionized water dispersion of graphene oxide and stir at 420 rpm for 0.5 h to obtain a mixed dispersion; the mass ratio of copper quantum dots to graphene oxide is 0.4%; the concentration of the deionized water dispersion of graphene oxide is 1.4 mg / mL; add ammonium persulfate as an oxidant to the mixed dispersion and stir at 380 rpm for 0.5 h to obtain a reaction solution; the mass ratio of oxidant to pyrrole monomer is 3.1:1. (2) Add pyrrole monomer to the reaction solution and react for 10.5 h in an ice-water bath (0 °C) to obtain graphene oxide / polypyrrole composite dispersion; the mass ratio of pyrrole monomer to graphene oxide is 4:1; (3) Add ascorbic acid as a reducing agent to the graphene oxide / polypyrrole composite dispersion, react at 86℃ for 5.5h, filter, wash alternately with ethanol and deionized water, and dry in a vacuum drying oven to obtain the three-dimensional graphene / polypyrrole nanosheet composite material; the mass ratio of reducing agent to graphene oxide is 2.8:1. (4) The dianhydride monomer and diamine monomer were dispersed in the organic solvent N,N-dimethylacetamide and reacted at 30°C for 8 hours to obtain a polyamic acid solution. A three-dimensional graphene / polypyrrole nanosheet composite material was added to the polyamic acid solution and ultrasonically dispersed until uniform. Then, an imidizing agent was added and reacted for 3 hours to perform partial imidization. After standing, a hydrogel was prepared by solvent exchange with deionized water. The molar ratio of the dianhydride monomer to the diamine monomer was 1.02:1. The mass ratio of the sum of the dianhydride monomer and the diamine monomer to the mass of the three-dimensional graphene / polypyrrole nanosheet composite material was... 3.5:1; the mass ratio of the sum of the dianhydride monomers and the diamine monomers to the organic solvent is 4 wt%; the dianhydride monomer is a mixture of 3,3',4,4'-benzophenone tetracarboxylic dianhydride and 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride in a molar ratio of 1:1; the diamine monomer is a mixture of 4,4'-diaminodiphenyl ether and 4,4'-diaminodiphenyl sulfone in a molar ratio of 1:4; the imidizing agent is a mixture of acetic anhydride and pyridine in a molar ratio of 2:1, and the mass of the mixture is 1.7 times the sum of the masses of the dianhydride monomers and the diamine monomers.

[0068] (5) The hydrogel was freeze-dried and then subjected to thermal imidization at 160℃ / 1h and 180℃ / 2h. After pulverization, a highly conductive aerogel powder was obtained. The corresponding polypropylene composite material was tested and found to have a tensile strength of 41.6 MPa, a flexural strength of 51.2 MPa, and a volume resistivity of 2.9 × 10⁻⁶. 7 Ω·m.

[0069] Example 10 A method for preparing a highly conductive aerogel powder includes the following steps: (1) Add copper quantum dots to a deionized water dispersion of graphene oxide and stir at 410 rpm for 0.5 h to obtain a mixed dispersion; the mass ratio of copper quantum dots to graphene oxide is 0.32%; the concentration of the deionized water dispersion of graphene oxide is 1.6 mg / mL; add ammonium persulfate as an oxidant to the mixed dispersion and stir at 380 rpm for 0.5 h to obtain a reaction solution; the mass ratio of oxidant to pyrrole monomer is 3.3:1. (2) Add pyrrole monomer to the reaction solution and react for 9.5 h in an ice-water bath (0 °C) to obtain graphene oxide / polypyrrole composite dispersion; the mass ratio of pyrrole monomer to graphene oxide is 5.5:1; (3) Add ascorbic acid as a reducing agent to the graphene oxide / polypyrrole composite dispersion, react at 88°C for 4.8 h, filter, wash alternately with ethanol and deionized water, and dry in a vacuum drying oven to obtain the three-dimensional graphene / polypyrrole nanosheet composite material; the mass ratio of reducing agent to graphene oxide is 1.9:1; (4) The dianhydride monomer and diamine monomer were dispersed in the organic solvent N,N-dimethylacetamide and reacted at 30°C for 8 h to obtain a polyamic acid solution. The three-dimensional graphene / polypyrrole nanosheet composite material was added to the polyamic acid solution and ultrasonically dispersed evenly. Then, an imidizing agent was added and reacted for 3 h to perform partial imidization. After standing, a hydrogel was prepared by solvent exchange with deionized water. The molar ratio of the dianhydride monomer to the diamine monomer was 1.02:1. The sum of the masses of the dianhydride monomer and the diamine monomer and the mass of the three-dimensional graphene / polypyrrole nanosheet composite material were... The ratio is 2.4:1; the mass ratio of the sum of the dianhydride monomers and the diamine monomers to the organic solvent is 4 wt%; the dianhydride monomers are a mixture of 3,3',4,4'-biphenyltetracarboxylic dianhydride and 3,3',4,4'-benzophenonetetracarboxylic dianhydride in a molar ratio of 2:1; the diamine monomers are a mixture of 4,4'-diaminobenzophenone and 4,4'-diaminodiphenyl sulfone in a molar ratio of 1:2; the imidizing agent is a mixture of acetic anhydride and pyridine in a molar ratio of 2:1, and the mass of the mixture is 2.1 times the sum of the masses of the dianhydride monomers and the diamine monomers.

[0070] (5) The hydrogel was freeze-dried and then subjected to thermal imidization at 160℃ / 1h and 180℃ / 2h. After pulverization, a highly conductive aerogel powder was obtained. The corresponding polypropylene composite material was tested and found to have a tensile strength of 42.3 MPa, a flexural strength of 50.7 MPa, and a volume resistivity of 6.2 × 10⁻⁶. 7 Ω·m.

[0071] Example 11 A method for preparing a highly conductive aerogel powder includes the following steps: (1) Add copper quantum dots to a deionized water dispersion of graphene oxide and stir at 400 rpm for 0.5 h to obtain a mixed dispersion; the mass ratio of copper quantum dots to graphene oxide is 0.38%; the concentration of the deionized water dispersion of graphene oxide is 1.5 mg / mL; add ammonium persulfate as an oxidant to the mixed dispersion and stir at 400 rpm for 0.5 h to obtain a reaction solution; the mass ratio of oxidant to pyrrole monomer is 3:1. (2) Add pyrrole monomer to the reaction solution and react for 10 h in an ice-water bath (0℃) to obtain graphene oxide / polypyrrole composite dispersion; the mass ratio of pyrrole monomer to graphene oxide is 5:1; (3) Add ascorbic acid as a reducing agent to the graphene oxide / polypyrrole composite dispersion, react at 85°C for 4.5 h, filter, wash alternately with ethanol and deionized water, and dry in a vacuum drying oven to obtain the three-dimensional graphene / polypyrrole nanosheet composite material; the mass ratio of reducing agent to graphene oxide is 2:1. (4) The dianhydride monomer and diamine monomer were dispersed in the organic solvent N,N-dimethylacetamide and reacted at 30°C for 8 hours to obtain a polyamic acid solution. A three-dimensional graphene / polypyrrole nanosheet composite material was added to the polyamic acid solution and ultrasonically dispersed until uniform. Then, an imidizing agent was added and reacted for 3 hours to perform partial imidization. After standing, a hydrogel was prepared by solvent exchange with deionized water. The molar ratio of the dianhydride monomer to the diamine monomer was 1.02:1. The mass ratio of the sum of the dianhydride monomer and the diamine monomer to the mass of the three-dimensional graphene / polypyrrole nanosheet composite material was... 2.8:1; the mass ratio of the sum of the dianhydride monomers and the diamine monomers to the organic solvent is 4 wt%; the dianhydride monomer is a mixture of 3,3',4,4'-benzophenone tetracarboxylic dianhydride and 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride in a molar ratio of 1:2; the diamine monomer is a mixture of 4,4'-diaminobenzophenone and 4,4'-diaminodiphenyl sulfone in a molar ratio of 2:1; the imidizing agent is a mixture of acetic anhydride and pyridine in a molar ratio of 2:1, and the mass of the mixture is 2.1 times the sum of the masses of the dianhydride monomers and the diamine monomers.

[0072] (5) The hydrogel was freeze-dried and then subjected to thermal imidization at 160℃ / 1h and 180℃ / 2h. After pulverization, a highly conductive aerogel powder was obtained. The corresponding polypropylene composite material was tested and found to have a tensile strength of 42.5 MPa, a flexural strength of 52.8 MPa, and a volume resistivity of 7.8 × 10⁻⁶. 6 Ω·m.

[0073] Comparative Example 1 A method for preparing aerogel powder includes the following steps: (1) Add copper quantum dots to a deionized water dispersion of graphene oxide and stir at 400 rpm for 0.5 h to obtain a mixed dispersion; the mass ratio of copper quantum dots to graphene oxide is 0.38%; the concentration of the deionized water dispersion of graphene oxide is 1.5 mg / mL; add pyrrole monomer to the mixed dispersion and stir at 400 rpm for 0.5 h to obtain a reaction solution; the mass ratio of pyrrole monomer to graphene oxide is 5:1. (2) Add ammonium persulfate as an oxidant to the reaction solution and react for 10 h in an ice-water bath (0 °C) to obtain a graphene oxide / polypyrrole composite dispersion; the mass ratio of oxidant to pyrrole monomer is 3:1. (3) Add ascorbic acid as a reducing agent to the graphene oxide / polypyrrole composite dispersion, react at 85°C for 4.5 h, filter, wash alternately with ethanol and deionized water, and dry in a vacuum drying oven to obtain the graphene / polypyrrole composite material; the mass ratio of reducing agent to graphene oxide is 2:1. (4) The dianhydride monomer and diamine monomer were dispersed in the organic solvent N,N-dimethylacetamide and reacted at 30°C for 8 hours to obtain a polyamic acid solution. Graphene / polypyrrole composite material was added to the polyamic acid solution and ultrasonically dispersed until uniform. Then, an imidizing agent was added and reacted for 3 hours to perform partial imidization. After standing, a hydrogel was prepared by solvent exchange with deionized water. The molar ratio of the dianhydride monomer to the diamine monomer was 1.02:1. The mass ratio of the sum of the dianhydride monomer and the diamine monomer to the mass of the graphene / polypyrrole composite material was 2.8:1. The total mass ratio of the dianhydride monomer and the diamine monomer to the organic solvent is 4 wt%; the dianhydride monomer is a mixture of 3,3',4,4'-benzophenone tetracarboxylic dianhydride and 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride in a molar ratio of 1:2; the diamine monomer is a mixture of 4,4'-diaminobenzophenone and 4,4'-diaminodiphenyl sulfone in a molar ratio of 2:1; the imidizing agent is a mixture of acetic anhydride and pyridine in a molar ratio of 2:1, and the mass of the mixture is 2.1 times the total mass of the dianhydride monomer and the diamine monomer.

[0074] (5) The hydrogel was freeze-dried and then subjected to thermal imidization at 160℃ / 1h and 180℃ / 2h. After pulverization, aerogel powder was obtained. The corresponding polypropylene composite material was tested and found to have a tensile strength of 38.3 MPa, a flexural strength of 47.5 MPa, and a volume resistivity of 8.5 × 10⁻⁶. 9 Ω·m.

[0075] Comparative Example 2 A method for preparing aerogel powder includes the following steps: (1) Add copper quantum dots to a deionized water dispersion of graphene and stir at 400 rpm for 0.5 h to obtain a mixed dispersion; the mass ratio of copper quantum dots to graphene is 0.38%; the concentration of the deionized water dispersion of graphene is 1.5 mg / mL; add ammonium persulfate as an oxidant to the mixed dispersion and stir at 400 rpm for 0.5 h to obtain a reaction solution; the mass ratio of oxidant to pyrrole monomer is 3:1. (2) Add pyrrole monomer to the reaction solution and react for 10 h in an ice-water bath (0℃) to obtain graphene / polypyrrole composite dispersion; the mass ratio of pyrrole monomer to graphene is 5:1; filter, wash alternately with ethanol and deionized water, and dry in a vacuum drying oven to obtain graphene / polypyrrole composite material. (4) The dianhydride monomer and diamine monomer were dispersed in the organic solvent N,N-dimethylacetamide and reacted at 30°C for 8 hours to obtain a polyamic acid solution. Graphene / polypyrrole composite material was added to the polyamic acid solution, and after ultrasonic dispersion, an imidizing agent was added and reacted for 3 hours to perform partial imidization. After standing, a hydrogel was prepared by solvent exchange with deionized water. The molar ratio of the dianhydride monomer to the diamine monomer was 1.02:1; the mass ratio of the sum of the dianhydride monomer and the diamine monomer to the mass of the graphene / polypyrrole nanosheet composite material was 2.8: 1; The mass ratio of the sum of the dianhydride monomers and the diamine monomers to the organic solvent is 4 wt%; the dianhydride monomer is a mixture of 3,3',4,4'-benzophenone tetracarboxylic dianhydride and 2,2'-bis(3,4-dicarboxylic acid)hexafluoropropane dianhydride in a molar ratio of 1:2; the diamine monomer is a mixture of 4,4'-diaminobenzophenone and 4,4'-diaminodiphenyl sulfone in a molar ratio of 2:1; the imidizing agent is a mixture of acetic anhydride and pyridine in a molar ratio of 2:1, and the mass of the mixture is 2.1 times the sum of the masses of the dianhydride monomers and the diamine monomers.

[0076] (5) The hydrogel was freeze-dried and then subjected to thermal imidization at 160℃ / 1h and 180℃ / 2h. After pulverization, aerogel powder was obtained. The corresponding polypropylene composite material was tested and found to have a tensile strength of 38.1 MPa, a flexural strength of 48.9 MPa, and a volume resistivity of 2.2 × 10⁻⁶. 9 Ω·m.

[0077] Figure 1 and Figure 2 The images shown are transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images of the three-dimensional graphene / polypyrrole nanosheet composite material prepared in Example 11. Figure 1 It can be seen that after the polymerization reaction, graphene still maintains its complete sheet structure, and the composite material has good dispersibility without agglomeration, indicating that the formation of polypyrrole nanosheets promotes the dispersion of graphene. Figure 2Scanning electron microscopy (SEM) images reveal the formation of regularly arranged, vertically aligned polypyrrole nanosheets on the graphene surface, with numerous voids between them. This void structure facilitates thorough wetting of the polyamic acid solution, enhancing the interfacial forces between the three-dimensional graphene / polypyrrole nanosheet composite and the polyimide resin. Figure 3 The image shows a scanning electron microscope (SEM) image of the highly conductive aerogel powder prepared in Example 11. As can be seen from the image, the aerogel has abundant porosity, indicating that the polyimide resin fully impregnates the three-dimensional graphene / polypyrrole nanosheet composite material. At the same time, the abundant porosity of the aerogel is conducive to the entry of polypropylene melt, thereby improving the interfacial force between the aerogel powder and polypropylene.

[0078] Figure 4 and Figure 5 The images shown are transmission electron microscope (TEM) and scanning electron microscope (SEM) images of the graphene / polypyrrole composite material prepared in Comparative Example 1. Figure 4 The layered structure of graphene is no longer visible, indicating that graphene agglomeration has occurred in the graphene / polypyrrole composite material. Furthermore, from... Figure 5 Scanning electron microscopy images show that adding pyrrole monomer first affects the dispersion of the oxidant, preventing the formation of polypyrrole nanosheet structures. Instead, it forms an irregular granular stacked structure on the graphene surface, which is not conducive to the fusion of graphene / polypyrrole composite material with polyamic acid solution. Figure 6The image shows a scanning electron microscope (SEM) image of the aerogel powder prepared in Comparative Example 1. The image reveals a significant decrease in porosity and a smaller specific surface area. This is because the graphene / polypyrrole composite material prepared in Comparative Example 1 lacks a three-dimensional porous structure. This results in weak interfacial bonding with polyimide and difficulty in dispersion within the polyimide precursor. During freeze-drying and thermal imidization, uneven stress occurs within the gel powder system, leading to pore wall collapse and reduced porosity. Polyimide, as a polar resin, possesses higher electrical conductivity than polyolefins. When the conductive filler is prepared into an aerogel, each aerogel powder particle itself constitutes a complete, continuous, three-dimensionally interconnected conductive network. When these conductive networks are dispersed in polyolefins, conductivity no longer depends on accidental contact between sheets, but rather on the contact between the entire conductive filler. Because each particle is highly conductive, only a low particle size is needed to construct a complete conductive network within the polyolefin matrix, significantly reducing the percolation threshold. Specifically, in terms of mechanical properties, the three-dimensional graphene / polypyrrole nanosheet composite material in the aerogel powder is fixed and separated in situ by the polyimide framework, forming a stable three-dimensional structure. During blending, it is necessary to disperse aerogel particles with good strength and toughness, rather than the more brittle three-dimensional graphene / polypyrrole nanosheet composite material, which can effectively avoid the cracking and agglomeration of the three-dimensional graphene / polypyrrole nanosheet composite material. Overall, the polyimide framework in the aerogel powder encapsulates and fixes the brittle graphene and polypyrrole in its three-dimensional network, which not only improves the solvent resistance and aging resistance of polypyrrole, but also provides physical protection for the conductive pathways, making the conductive and mechanical properties of the composite material more stable and slower to degrade during repeated deformation, friction, or long-term use.

[0079] Based on the relevant data, it can be seen that, compared with Example 11, Comparative Example 1 added pyrrole monomers to the mixed dispersion first, followed by the oxidant. The premature addition of pyrrole monomers affected the adsorption and enrichment of the oxidant by the copper quantum dots, which was detrimental to the co-catalytic effect of the copper quantum dots and prevented the formation of nanosheet structures. This led to the polymerization of pyrrole monomers on the surface of graphene oxide, which not only hindered the dispersion and reduction process of graphene oxide but also affected the formation of the conductive network in the aerogel powder, resulting in a decrease in the mechanical strength and electrical conductivity of the polyolefin composite material. In contrast, Comparative Example 2 used graphene as the starting carbon material. Compared with graphene oxide, graphene lacks oxygen-containing functional groups on its surface, resulting in poor dispersibility and hindering the adhesion of copper quantum dots, thus failing to play a carrier role and leading to a decrease in the performance of the composite material. The experimental data above demonstrate that the polyimide framework in the aerogel powder encapsulates and fixes brittle graphene and polypyrrole within its three-dimensional network. This not only improves the solvent resistance and aging resistance of polypyrrole but also provides physical protection for the conductive pathways, resulting in more stable electrical and mechanical properties and slower degradation of the composite material under repeated deformation, friction, or long-term use. By constructing a three-dimensional hierarchical conductive network, the transformation of resins such as polyolefins from insulators to conductors or semiconductors can be achieved with a lower filler load, while maintaining good processability and mechanical properties. Using this highly conductive aerogel powder as a conductive filler for resins further improves its conductivity while maintaining the high mechanical properties of the resin, solving the technical problem of reduced mechanical properties of composite materials caused by the addition of ordinary conductive fillers.

[0080] The above embodiments are not intended to limit the content of the composition of the present invention. Any minor modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention or the composition or content of the composition shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a highly conductive aerogel powder, characterized in that, Includes the following steps: (1) First, prepare a mixed dispersion of copper quantum dots / graphene oxide, then add an oxidant and stir until homogeneous to obtain a reaction solution; (2) Add pyrrole monomer to the reaction solution and react under ice-water bath conditions to obtain graphene oxide / polypyrrole composite dispersion; (3) The graphene oxide / polypyrrole composite dispersion was reduced, filtered, washed and dried to obtain a three-dimensional graphene / polypyrrole nanosheet composite material; (4) The three-dimensional graphene / polypyrrole nanosheet composite material was added to a polyamic acid solution, and after sonication, a chemical imidizing agent was added to partially imidize it; it was allowed to stand, and then solvent exchange was performed with deionized water to prepare a hydrogel. (5) The hydrogel was freeze-dried, thermally imidized, and pulverized to obtain a highly conductive gas gel powder.

2. The method for preparing a highly conductive aerogel powder as described in claim 1, characterized in that, In step (1), the oxidant is one or more of ammonium persulfate, potassium persulfate, sodium bisulfite, and azobisisobutyronitrile.

3. The method for preparing a highly conductive aerogel powder as described in claim 1, characterized in that, The reaction time in step (2) is 8-12 hours.

4. The method for preparing a highly conductive aerogel powder as described in claim 1, characterized in that, The reduction in step (3) is carried out by chemical reduction.

5. The method for preparing a highly conductive aerogel powder as described in claim 1, characterized in that, In step (4), the polyamic acid solution is prepared by polymerizing dianhydride monomer and diamine monomer in an organic solvent.

6. The method for preparing a highly conductive aerogel powder as described in claim 5, characterized in that, The molar ratio of dianhydride monomer to diamine monomer is (1-1.04):

1.

7. The method for preparing a highly conductive aerogel powder as described in claim 5, characterized in that, The polymerization process takes place at a temperature of 25-35℃ for 6-12 hours.

8. A highly conductive gas-conducting gel powder, characterized in that, It is prepared by the method for preparing a highly conductive aerogel powder according to any one of claims 1-7.

9. The application of the highly conductive aerogel powder as described in claim 8 in the preparation of battery materials, sensor materials, capacitor materials, detector materials, conductive plates, conductive pipes, and grouting materials.

10. A polyolefin composite material, characterized in that, The product comprises the following components in parts by weight: 50-150 parts of polyolefin resin, 10-50 parts of the highly conductive aerogel powder according to claim 8, and 1-10 parts of processing aids.

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