Normal-temperature and normal-pressure high-conductivity micro-nano material based on copper-doped lead apatite and preparation and application thereof

Abstract

The invention relates to a normal-temperature and normal-pressure high-conductivity micro-nano material based on copper-doped lead apatite as well as preparation and application thereof. The chemical general formula of the material is Pb10-XCux (PO4) 6O, x is more than 0.95 and less than 1.05, the material has a hexagonal system apatite structure, Cu < 2 + > occupies a lattice 4f site and forms a [CuO5] pyramid unit, strong electroacoustic coupling is realized through Jahn-Teller distortion, and the material shows excellent conductivity at normal temperature and normal pressure. The room temperature resistivity of the material is less than or equal to 0.05 mu omega.cm, the critical current density is greater than or equal to 1.2 * 10 < 6 > A / cm < 2 >, and the sulfur impurity content is less than or equal to 0.05 at% The invention further discloses a gradient sulfur control heat treatment method, and the purity and the conductive stability of the material are remarkably improved. The material is suitable for a power transmission system, is particularly suitable for a high-conductivity component without cooling, and has the advantages of high current carrying capacity, high environmental resistance, low cooling cost and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of materials science and functional materials, and particularly to a room-temperature and atmospheric-pressure highly conductive micro-nano material based on copper-doped lead apatite, as well as a preparation method of the material and its applications in fields such as power transmission. Specifically, the present invention belongs to the technical field of design, synthesis and integrated application of high-performance micro-nano structured conductive materials, and has broad application prospects in energy, power and electronic information engineering. Background Art

[0002] Under the background of the rapid development of current materials science and engineering technology, micro-nano materials have become key materials in many frontier application fields due to their remarkable size effect, surface effect and quantum size effect, etc., especially showing great application potential in high-end technology fields such as electronic devices, energy transmission and quantum computing.

[0003] Traditional highly conductive materials, such as copper-based or silver-based conductors, although having relatively high electrical conductivity, usually have many technical bottlenecks restricting their wide application. For example, when achieving extremely high conductivity, such materials often rely on a low-temperature (such as liquid nitrogen or liquid helium) environment to maintain their superconducting or quasi-superconducting state, resulting in huge pressure on the overall system in terms of energy consumption, operation and maintenance, and cost control. In addition, the preparation process of traditional materials is complex, with high requirements for environmental conditions and material purity, further increasing the difficulty and threshold of industrial application.

[0004] Under this background, researchers have begun to attempt to explore new micro-nano material systems based on doping modification in order to break through the limitations of traditional highly conductive materials in terms of structural stability, preparation feasibility and environmental adaptability. Among them, the apatite structure has become a potential material platform due to its unique crystal channels and adjustable lattice sites. However, existing copper-doped apatite materials mainly focus on non-electrical performance application fields such as catalysis, and the exploration and application in terms of conductivity are still blank.

[0005] In addition, in the existing literature reports, highly conductive micro-nano materials often need to work under high-temperature or high-pressure environments in practical applications to exhibit their excellent conductivity. This limitation seriously hinders their large-scale deployment in application scenarios such as portable devices, room-temperature electronic components, and power systems. At the same time, the structural stability, service life and reliability of the materials under different working environments have not been fully solved.

[0006] Therefore, there is an urgent need to develop a new type of micro-nano material system that can work stably under normal temperature and pressure conditions, has high electrical conductivity, simple preparation process, high controllability, and is applicable to a variety of environments and application scenarios. This material should not only solve the dependence of traditional conductive materials on extreme environments, but also improve its overall performance and application efficiency to promote the transition of related high-conductivity technologies from the laboratory to practical engineering and industrial applications. Summary of the Invention

[0007] Based on the technical problems existing in the structural controllability, resistivity control, process adaptability, etc. of the above-mentioned room-temperature high-conductive materials, the present invention provides a room-temperature and normal-pressure high-conductive micro-nano material based on copper-doped lead apatite. Through crystal structure regulation and doping design, this material achieves ultra-low resistivity and high critical current density under normal temperature and pressure conditions, effectively solving the problems of dependence of traditional high-conductive materials on low-temperature extreme conditions, poor stability of electrical conductivity, and high preparation difficulty.

[0008] In a possible implementation manner, the present invention provides a room-temperature and normal-pressure high-conductive micro-nano material based on copper-doped lead apatite. The chemical general formula of this material is Pb 10-X Cu x (PO4)6O, where 0.95 < x < 1.05; this component range ensures that the doping amount of copper ions is within the allowable range of the crystal structure, avoiding the formation of metal clusters or impurity phases and improving the stability of the main phase. The material has a hexagonal crystal system apatite structure, and the space group is P63 / m,

[0009] The lattice constants are a = 9.83 - 9.86 Å, c = 7.41 - 7.45 Å, constructing a quasi-one-dimensional electron channel formed along the c-axis direction, which is conducive to the stable migration of free carriers. The lattice constants are preferably a = 9.843 Å, c = 7.428 Å. And this material satisfies the following performance parameters:

[0010] Room temperature (300K) resistivity ≤ 0.05 μΩ·cm (measured by the four-probe method);

[0011] Critical current density ≥ 1×10 6 A / cm 2 (at 77K, under 0T magnetic field);

[0012] Sulfur impurity content ≤ 0.05 at% (detected by ICP-MS).

[0013] The above performance reflects that this material not only has the characteristic of low resistivity, but also has good anti-impurity interference ability, ensuring long-term stable operation in the high-conductive state.

[0014] In one possible embodiment, the copper ions in the material primarily occupy the 4f sites of the apatite lattice, forming a [CuO5] pyramidal structural unit with the surrounding pentacoordinate oxygen atoms, exhibiting pronounced Jahn-Teller distortion. This distortion effect modulates the local crystal field, inducing enhanced electroacoustic coupling and forming a strong electroacoustic coupling system with a coupling constant λ of 1.8. This mechanism provides a physical basis for achieving high electrical conductivity while breaking the traditional BCS theory's critical temperature limitation, enabling the material to exhibit quasi-zero resistance at room temperature and pressure.

[0015] In one possible embodiment, the material is further limited to other electrical parameters at 300K: the magnetic susceptibility X≤-0.98 (by SQUID test, applying a 1Oe magnetic field), indicating that the material has nearly completely diamagnetic Meissner behavior; the carrier concentration n is 1.1 to 1.3×10 22 cm -3 , the mobility μ is between 210 and 230 cm 2 / V·s, indicating that the material has a high free carrier density and good electron mobility. These indicators verify the reliability and advanced nature of the material's high conductivity from the perspective of microscopic charge transport mechanism.

[0016] In one possible embodiment, the present invention further provides a method for preparing a high-conductivity micro-nano material at room temperature and pressure based on copper-doped lead apatite, the method comprising the following steps:

[0017] Step 1: Synthesize Cu3P crystals. Cu and P are accurately weighed and mixed in a molar ratio, and then sealed in a vacuum sealed tube. The mixture is reacted at a constant temperature of 550°C for 48±0.5 hours to ensure the formation of pure Cu3P crystals as a stable intermediate for providing a Cu source.

[0018] Step 2: Synthesize the lead sulfate ore precursor by mixing PbO and PbSO4 powders in a mass ratio of 1:1 and heating them at 725°C in an air atmosphere for 24±0.5 hours to obtain a precursor with good crystallinity, which provides the Pb source and crystal skeleton for subsequent reactions.

[0019] Step 3: Grind and mix the Cu3P and lead sulfate ore precursor until the average particle size D50 is ≤ 5 μm. After improving the mixing uniformity, seal the mixture in a vacuum tube and perform the following gradient sulfur control process to accurately control the sulfur content:

[0020] S310: vacuum degree ≤5×10 -4 Under Torr conditions, heat to 600±20℃ at 5±1℃ / min and keep warm for 1 hour to promote SO2 volatilization and remove sulfur impurities;

[0021] S320: Switch to an argon environment with a purity of ≥99.9995%, continuously heat up to 925 ± 5 °C and hold for 15 hours to achieve high-temperature crystal transformation and complete the construction of phase stabilization.

[0022] Step 4: The sample after the aforementioned sulfur control treatment is annealed in an argon environment at 750 °C for 3 hours to further improve crystal integrity and reduce the density of grain boundary defects, and finally naturally cooled to room temperature to obtain the target material with high electrical conductivity.

[0023] In a possible implementation, the above sample is confirmed by three parallel ICP-MS detections, with a standard deviation ≤ 0.005 at%, and the residual sulfur content is stably controlled at ≤ 0.05 at%. This low sulfur residue level significantly avoids the interference of the Cu2S heterophase, effectively reduces the false conduction behavior and weak diamagnetic interference, and improves the overall purity and functional reliability of the material.

[0024] In a possible implementation, a specific application solution of the high-conductivity micro-nano material in the power transmission system is provided: using this material in cable conductors or connectors, making full use of its low-resistance characteristics under normal temperature and pressure conditions to improve energy transmission efficiency, significantly reducing the operating cost originally relying on a low-temperature cooling system, and promoting the construction of a green and energy-saving power system.

[0025] In a possible implementation, the material has excellent environmental adaptability and can stably maintain high electrical conductivity under extreme working conditions such as high temperature (>85 °C), high humidity (RH > 90%) or strong magnetic field (>2 T), ensuring its reliable application in complex power systems and special industrial environments.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] 1. Achieve high electrical conductivity at normal temperature and pressure: The most significant effect of the present invention is the successful realization of high electrical conductivity of the high-conductivity micro-nano material at normal temperature and pressure, breaking the problem that traditional high-conductivity materials must work at extremely low temperatures (such as liquid nitrogen or liquid helium temperatures). This means that the application of high-conductivity micro-nano materials no longer depends on expensive low-temperature cooling systems, greatly reducing the application cost of high-conductivity technology and improving the feasibility of practical applications.

[0028] 2. Improve electrical conductivity and stability: Under the design of the micro-nano structure, the high-conductivity micro-nano material exhibits higher electrical conductivity and better stability than traditional high-conductivity materials. This enables the high-conductivity micro-nano material to withstand a larger current density without loss or degradation, and still maintain stable high electrical conductivity especially in high-current and high-magnetic-field environments.

[0029] 3. Reduction in production cost: Through innovative preparation processes, the production cost of highly conductive micro-nano materials is significantly reduced compared to traditional low-temperature highly conductive materials. The more efficient preparation process also enables large-scale production.

[0030] 4. Good adaptability: The design of highly conductive micro-nano materials enables them to exhibit good adaptability in different environments and applications. They can operate stably under conditions such as high temperature, high humidity, and strong magnetic fields. This adaptability greatly expands the application scope of the materials.

[0031] 5. Efficiency improvement: Highly conductive micro-nano materials can be used as key materials in power transmission systems, with the remarkable effects of significantly reducing energy loss and improving transmission efficiency. A high-conductivity power transmission system operating at room temperature can greatly reduce heat loss during energy transmission, resulting in a substantial increase in power transmission efficiency.

[0032] 6. In this invention, a Cu doping amount of x > 0.9 causes the lattice constant a to shrink from 9.92 Å to 9.843 Å and the c-axis to expand from 7.40 Å to 7.428 Å, forming a more stable quasi-one-dimensional conductive channel. The critical current density increases by three orders of magnitude (from 10 3 A / cm 2 to 10 6 A / cm 2 ).

[0033] 7. The gradient sulfur control process precisely regulates the sulfur content through a two-step method: In the first step, vacuum heating (580 - 620 °C) promotes the volatilization of sulfur elements in the form of SO2, reducing the residual sulfur content to 0.5 at%. In the second step, high-temperature treatment (920 - 930 °C) in an argon environment further eliminates sulfur impurities at grain boundaries, reducing the sulfur residue to ≤ 0.05 at%. Comparative experiments show (see Table 1) that when the sulfur residue is reduced from 0.5 at% to 0.05 at%, the room-temperature resistivity of the material decreases by three orders of magnitude (from 1.2 μΩ·cm to 0.02 μΩ·cm), the critical current density increases to 1.2×10 6 A / cm 2 , the carrier concentration n = 1.2×10 22 cm -3 , and the mobility μ = 220 cm 2 / V·s.

[0034] In summary, the invention effects of the novel highly conductive micro-nano materials are manifested as the realization of high conductivity at normal temperature and pressure, the improvement of conductivity and stability, the significant reduction in production cost, and the extensive application potential in multiple fields. These achievements will promote the transition of the novel highly conductive micro-nano materials from the laboratory to practical applications, bringing revolutionary changes to fields such as energy, information technology, and transportation. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings illustrate various embodiments by way of example rather than limitation, and together with the description and claims are used to explain the embodiments of the invention. Where appropriate, the same reference numerals are used throughout the drawings to refer to the same or similar parts. Such embodiments are illustrative and are not intended to be exhaustive or exclusive embodiments of the device or method.

[0036] Figure 1 Schematic diagram of the crystal structure of the high-conductivity micro-nano material of the present invention;

[0037] Figure 2 Process flow chart for the preparation of the high-conductivity micro-nano material. Detailed implementation manners

[0038] To further illustrate the technical content of the present invention, the implementation manners of a copper-doped lead apatite high-conductivity micro-nano material are described in detail below in combination with structural design, process flow, and comparative experiments. It should be noted that the implementation manners are only used to explain the principle and feasibility of the present invention and do not limit its protection scope.

[0039] The material of the present invention adopts the chemical general formula Pb 10-X Cu x (PO4)6O, where (0.95 < x < 1.05), to dope Cu 2 + to construct a new type of conductive framework structure. Copper ions preferentially occupy the 4f lattice sites in the hexagonal apatite structure and form a [CuO5] pyramid structure unit with five surrounding oxygen atoms. This structure has obvious Jahn-Teller distortion characteristics, which is conducive to generating strong electron-phonon coupling. In the design of the present invention, the coupling constant λ reaches 1.8, breaking through the traditional limit of the BCS theory on the high-conductivity transition temperature, so that the material exhibits high conductivity under normal temperature and pressure conditions.

[0040] Provide a preparation method for a room-temperature and normal-pressure high-conductivity micro-nano material based on copper-doped lead apatite:

[0041] I. Design of the high-conductivity micro-nano material

[0042] Chemical composition design: The chemical general formula of the high-conductivity micro-nano material is Pb 10-X Cu x (PO4)6O, where (0.95 < x < 1.05), where Cu 2+ replaces Pb 2+Occupying the 4f lattice sites, with lattice constants a = 9.843 Å and c = 7.428 Å, it forms a [CuO5] pyramid structural unit arranged along the c-axis. This structure induces strong electron-phonon coupling (coupling constant λ = 1.8) through Jahn-Teller distortion, achieving a zero-resistance state at room temperature. Here, 0.9 < x < 1.1, and it is a copper-doped lead apatite structure compound. This design changes the electronic structure and physical properties of the material by introducing copper ions into the lead apatite structure, making it possible for the material to exhibit high conductivity characteristics.

[0043] Crystal structure design: The high-conductivity micro-nano material has a hexagonal crystal system structure similar to apatite, with a space group of P63 / m, and its lattice constants α = 9.843 Å and c = 7.428 Å. This crystal structure provides a specific atomic arrangement and chemical bonding mode for the material, which is conducive to electron conduction and the formation of a high-conductivity morphology.

[0044] II. Preparation process of high-conductivity micro-nano materials

[0045] We use the solid-phase method to synthesize high-conductivity micro-nano materials and prepare the raw materials for synthesis: PbO, PbSO4, Cu, and P.

[0046] To obtain lead sulfate ore, PbO and Pb(SO4) powders are uniformly mixed in a ceramic crucible at a ratio of 50% each. The mixed powder is heated in a furnace at 725 °C in air for 24 hours. During the heating process, a chemical reaction occurs in the mixed material to form lead sulfate ore.

[0047] To synthesize Cu3P, Cu and P powders are mixed in a crucible according to the component ratios. The mixed powder is sealed in a vacuum tube 20 cm long per gram, with a vacuum degree of 10 -3 Torr. The vacuum tube containing the mixed material is heated in a furnace at 550 °C for 48 hours. During this process, the mixed material undergoes a transformation to form Cu3P crystals.

[0048] The lead sulfate ore and Cu3P crystals are ground into powders and mixed in a crucible. Then, the mixed powder is sealed in a vacuum tube. When implementing the gradient sulfur control process, the following conditions need to be met: ① The mixed powder is ground to D50 ≤ 5 μm to ensure uniform distribution of sulfur elements; ② Vacuum stage: Evacuate to ≤ 5 × 10 -4 Torr, heat up to 600 ± 20 °C at a rate of 5 ± 1 °C / min, and hold for 1 hour; ③ Argon stage: Switch to argon with a purity ≥ 99.9995%, heat up to 925 ± 5 °C at a rate of 3 ± 0.5 °C / min, and hold for 15 hours; ④ Detection of sulfur residue: Use ICP-MS (detection limit 0.001 at%), and take the average value after parallel testing 3 times.

[0049] III. Post-treatment and Optimization of Highly Conductive Micro-Nano Materials

[0050] Annealing treatment: To improve the superconducting properties of the highly conductive micro-nano materials, the samples were annealed. The optimal annealing temperature was 750 °C (argon atmosphere), the annealing time was 3 hours, and the grain boundary defect density was reduced by 80%. The annealing treatment helps reduce the defects in the material and promotes the growth and arrangement of crystals.

[0051] Cooling process: During the cooling process after annealing, the material was gradually cooled to room temperature to avoid the accumulation of internal stress in the material caused by sudden temperature drop, which affects the high conductivity.

[0052] IV. Characterization and Testing

[0053] The synthesized highly conductive micro-nano materials were characterized using X-ray diffraction (XRD) technology to confirm their crystal structure and phase purity.

[0054] The Meissner effect was measured using a superconducting quantum interference device (SQUID). Complete diamagnetism (magnetic susceptibility χ = -1.0 ± 0.05) was observed at 300 K, confirming the existence of a high-conductivity state at room temperature.

[0055] After completing all the steps, the novel highly conductive micro-nano materials were fabricated.

[0056] Example 1:

[0057] As Figure 1 shown, the material is hexagonal, with a space group of P63 / m, lattice constants of a = 9.843 Å and c = 7.428 Å, and has a quasi-one-dimensional c-axis electron channel, providing a stable migration path for carriers. This structural design combines micro-nano scale characteristics, further enhancing the surface activity and conductivity efficiency.

[0058] In actual preparation, first, high-purity copper powder and red phosphorus powder were mixed at a molar ratio of 3:1, encapsulated in a quartz tube under argon protection, evacuated to 10 -3 Torr, and then heated at 550 °C for 48 hours to obtain Cu3P crystals. Subsequently, PbO and PbSO4 were mixed at a molar ratio of 1:1 and reacted in air at 725 °C for 24 hours to synthesize a lead sulfate mineral precursor. The two precursors were ball-milled and mixed and refined to D50 ≤ 5 μm to enhance the reaction activity.

[0059] The mixed precursor powder was placed in a quartz tube and subjected to the gradient-controlled sulfur heat treatment process as Figure 2 shown. First, in a vacuum environment (≤5 × 10 -4Heat to 600 °C under Torr and hold for 1 hour to volatilize the SO2 gas formed by the sulfur source, initially controlling the sulfur residue at about 0.5 at%. Subsequently, switch to high-purity argon (99.9995%) and heat to 925 °C and hold for 15 hours to further remove sulfur impurities at grain boundaries, so that the final sulfur residue ≤ 0.05 at%. Finally, the sample is annealed at 750 °C for 3 hours in an argon atmosphere and cooled with the furnace to reduce grain boundary defects and enhance crystal connectivity.

[0060] XRD testing was used to confirm that the crystal structure of the product was a pure hexagonal apatite phase, and no impurity phase peaks were detected. The sample was tested by ICP-MS in three parallel runs, and the sulfur residue was stably controlled within 0.05 at%, with a standard deviation ≤ 0.005 at%.

[0061] In terms of performance, the material of the embodiment of the present invention has a resistivity of 0.02 μΩ·cm at 300 K (four-probe method), and the critical current density is as high as 1.2×10 6 A / cm 2 (77 K, 0 T), and the magnetic susceptibility X = -1.0, showing complete diamagnetic properties. In addition, the carrier concentration n = 1.2×10 22 cm -3 , and the mobility μ = 220 cm 2 / V·s, showing significant metallic conduction characteristics and high carrier capacity.

[0062] To verify that the improvement in conductivity achieved by the technical solution of the present invention is significant, multiple comparative examples were set up. Except for adjustments in key variables (such as copper doping amount, sulfur content control, or heat treatment conditions), the preparation methods of the samples in each comparative example were the same as those of the embodiment of the present invention.

[0063] In Comparative Example 1, the sulfur control process was not used, and the sulfur residue in the material was about 0.5 at%. The test showed that the room temperature resistivity of this sample was 1.2 μΩ·cm, and the critical current density was only 10 3 A / cm 2 , two orders of magnitude lower than the sample of the present invention, and a weak diamagnetic signal appeared in the SQUID test, indicating that the impurity phase Cu2S caused a false conduction path.

[0064] In Comparative Example 2, the Cu doping amount was adjusted to x = 0.6, which was significantly deviated from the design range, and a impurity phase Pb3(PO 4)2 , and the resistivity increased to 10 4 ~10 5 μΩ·cm, showing an insulating state; the critical current density was almost zero, indicating that the conduction channel was not effectively formed.

[0065] In Comparative Example 3, the material was not fully annealed (750 °C, 3 hours), resulting in a high grain boundary defect rate. The resistivity reached 0.8 μΩ·cm, much higher than that of the samples of the present invention, and the magnetic susceptibility did not reach the completely diamagnetic state either.

[0066] The above experimental data clearly show that precise control of the Cu doping amount, suppression of the sulfur content, and annealing optimization play a decisive role in achieving high conductivity at room temperature. In contrast, the process flow adopted in the present invention can ensure the purity of the main phase, the continuity of the electron channels, and the crystal order simultaneously, thus achieving stable and excellent high conductivity performance.

[0067] In terms of applications, this material has high conductivity characteristics for operation at room temperature and is particularly suitable for high-efficiency power transmission systems, electronic interconnection structures, chip interconnection, connectors, high-power converters, etc. Compared with traditional superconducting materials that rely on liquid nitrogen cooling, the material of the present invention can obtain superconducting-like conductivity without increasing energy consumption and complex systems, significantly reducing the system operation and maintenance costs, and meeting the requirements of the high-efficiency and green development of modern energy systems. In addition, this material has good adaptability to temperature, humidity, and magnetic fields and is especially suitable for use in complex electromagnetic environments, such as rail transit, military equipment, quantum sensors, etc.

[0068] Table 1 Experimental data table

[0069]

[0070] Table 2 The influence of composition ratio and process method on the physical properties of the material

[0071]

[0072]

[0073] Table 3 Electrical properties under different processes

[0074]

[0075] Appendix 1 Note: When the sulfur residue amount decreases, the room temperature resistivity of the material decreases and the critical current density increases.

[0076] Appendix 2 Note: Differences in composition ratios (such as Cu doping amount, sulfur content, etc.) and process condition deviations will significantly affect the structure, impurity types, and physical properties of the material.

[0077] Appendix 3 Note: The corresponding electrical properties under different processes.

[0078] In summary, the present invention realizes a highly conductive micro-nano material that can operate at normal temperature and pressure by constructing a lead apatite micro-nano structure with quasi-one-dimensional [CuO5] conductive channels, in combination with a precise sulfur control process and optimized heat treatment. Compared with the prior art, it exhibits outstanding substantial features and remarkable progress in terms of material properties, process controllability, and application prospects, and has wide popularization value.

[0079] It should be noted that the above-described embodiments should be understood as illustrative and not limiting the protection scope of the present invention. The protection scope of the present invention is subject to the claims. For those skilled in the art, without departing from the essence and scope of the present invention, some non-essential improvements and adjustments made to the present invention still fall within the protection scope of the present invention.

Claims

1. A room-temperature and atmospheric-pressure highly conductive micro-nano material based on copper-doped lead apatite, characterized in that, The chemical general formula of the material is Pb 10-X Cu x (PO4)6O, where 0.95 < x < 1.05; The material has a hexagonal apatite structure with a space group of P63 / m, lattice constants a = 9.83 - 9.86 Å, c = 7.41 - 7.45 Å, and satisfies the following properties: Resistivity at room temperature (300 K) ≤ 0.05 μΩ·cm; Critical current density ≥ 1.2×10 6 A / cm 2 ; Sulfur impurity content ≤ 0.05 at%.

2. The ambient temperature and pressure highly conductive micro-nano material according to claim 1, characterized in that, In the material, copper ions occupy the lattice 4f sites and form [CuO5] pyramid structural units, and the electroacoustic coupling constant λ induced by Jahn-Teller distortion is 1.

8.

3. The room-temperature and atmospheric-pressure highly conductive micro-nano material according to claim 1 or 2, characterized in that, Under the conditions of 300 K and a magnetic field of 1 Oe, tested by SQUID, the magnetic susceptibility χ ≤ -0.98, and the carrier concentration n is 1.1 - 1.3×10 22 cm -3 , and the mobility μ is 210 - 230 cm 2 / V·s.

4. A method for preparing a room-temperature and atmospheric-pressure highly conductive micro-nano material according to any one of claims 1-3, characterized in that, It includes the following steps: Step S1: Synthesize Cu3P crystals. Mix Cu and P strictly according to a molar ratio of 3:1, and react in a vacuum-sealed tube at 550 °C for 48 ± 0.5 hours; Step S2: Synthesize a galena precursor. Mix PbO and PbSO4 powders according to a mass ratio of 1:1, heat in air to 725 °C, and keep warm for 24 ± 0.5 hours; Step S3: After grinding and mixing the above two precursors until D50 ≤ 5 μm, place them in a vacuum tube and perform the following gradient sulfur control process: S310: Heat up to 600 ± 20 °C under a vacuum of ≤ 5×10 -4 Torr and hold for 1 hour to volatilize SO2; S320: Transfer to an argon atmosphere with a purity ≥ 99.9995%, heat up to 925 ± 5 °C at a rate of 3 ± 0.5 °C / min, and keep warm for 15 hours; Step S4: Anneal the sulfur-controlled sample in an argon atmosphere at a temperature of 750 °C for 3 hours, and then cool naturally to room temperature to obtain the high-conductivity micro-nano material.

5. The preparation method according to claim 4, characterized in that, The sample is detected by ICP-MS in three parallel runs (standard deviation ≤ 0.005 at%), and the residual sulfur element content ≤ 0.05 at%.

6. Application of a high-conductivity micro-nano material based on copper-doped lead apatite in a power transmission system under normal temperature and pressure.

7. The application according to claim 6, characterized in that: The high-conductivity micro-nano material is applied to power cables or conductor connectors, and its low-resistance characteristics at normal temperature and pressure are used to achieve efficient electric energy transmission and reduce the system cooling cost.

8. The application according to claim 6, wherein: The material is suitable for power transmission systems in complex environments such as high temperature, high humidity, and strong magnetic fields.

Images