309results about How to "Low resistivity" patented technology

The invention discloses a composite positive electrode material and a preparation method thereof, a positive plate and a lithium ion battery. The composite positive electrode material comprises lithium iron phosphate and a carbon coating layer coating the surface of the lithium iron phosphate, wherein the integral intensity ratio ID / IG of a D peak to a G peak of the carbon coating layer in a Raman spectrum is 0.2-0.9, and the resistivity of the composite positive electrode material is 0.1-10 omega.cm. According to the preparation method, the graphitization degree of the carbon coating layer is controlled within a proper range (ID / IG is 0.2-0.9), so that good conductivity is ensured, and structural instability caused by excessive graphitization is avoided. The moderate graphitization degree is beneficial to formation of an ordered carbon layer structure, provides more electron transport channels and reduces the potential barrier of electron migration, so that the conductivity of the composite material is greatly improved, and the resistivity is reduced to an excellent level of 0.1-10 omega.cm.

The invention relates to an anti-static PP composite material and a preparation method thereof, and belongs to the technical field of high polymer materials. The antistatic PP composite material is prepared from the following components in parts by weight: 60 to 80 parts of PP resin, 10 to 20 parts of glass fiber, 0.1 to 0.5 part of a lubricant, 0.3 to 2 parts of a modified antistatic agent, 0.5 to 1.5 parts of a modified flame retardant and 0.2 to 0.8 part of an antioxidant, in the modified antistatic agent, an alkanolamide bond intermediate forms a conductive film, so that the resistivity is reduced, static dissipation is promoted, the material is endowed with lubricity, and the generation of static electricity is reduced; in addition, maleic anhydride forms a conductive layer and cooperates with quaternary ammonium salt to enhance hydrophilicity and accelerate charge transfer; a piperazine pyrophosphate derivative in the modified flame retardant and a phosphorus-nitrogen flame retardant cooperate to construct an expanded carbon layer to isolate a fire source and oxygen, so that the service life is prolonged; the anti-static PP composite material prepared by the invention not only has a good anti-static effect, but also has excellent flame-retardant and tensile properties.

The invention belongs to the technical field of crystal growth, and provides a low-resistivity silicon carbide single crystal growth method and system and a single crystal, silicon carbide powder is uniformly paved at the bottom of a graphite crucible, metal carbide material particles are uniformly paved on the surface of the silicon carbide powder, and silicon carbide seed crystals are adhered to the top of the graphite crucible; the graphite crucible is sealed, and the interior of the graphite crucible is vacuumized; heating the graphite crucible subjected to vacuumizing treatment, filling carrier gas into the graphite crucible, then slowly replacing the carrier gas with doped source gas, slowly increasing the growth pressure to a set pressure, and growing a buffer layer; after the growth of the buffer layer is completed, changing the growth condition to grow the heavily doped silicon carbide single crystal; and after the growth of the crystal is completed, cooling the graphite crucible subjected to vacuumizing treatment, so that the crystal is naturally cooled, and the low-resistivity silicon carbide single crystal is obtained. The doping concentration of the silicon carbide single crystal can be improved, and the resistivity of the silicon carbide material can be reduced.

The invention discloses an impact-resistant and distortion-resistant outdoor polyethylene power cable, and relates to the technical field of cables, the impact-resistant and distortion-resistant outdoor polyethylene power cable comprises a cable core, four annularly distributed wire cores are arranged in the cable core, each wire core is composed of an inner-layer conductor, an outer-layer conductor, a heat conduction enhancement layer, an inner enhancement layer and an inner insulation layer, a shielding combination layer is arranged outside a wrapping layer, and a shielding layer is arranged outside the wrapping layer. The shielding combination layer is composed of a high-conductivity metal thin film layer, a nanometer shielding layer and a protective coating, the anti-impact combination layer is arranged outside the shielding combination layer, the anti-impact combination layer is composed of an impact dispersion layer and an energy absorption layer, the anti-distortion combination layer is arranged outside the anti-impact combination layer, and the anti-distortion combination layer is composed of an impact dispersion layer and an energy absorption layer. The anti-distortion combination layer is composed of a core layer and an elastic buffer layer, an outer sheath is arranged outside the anti-distortion combination layer, and the outer sheath is composed of a reinforcing layer, a blocking layer and an outer protective layer, so that the problems that the power cable is poor in impact resistance and distortion resistance and inconvenient to maintain are solved.

The invention belongs to the technical field of oxide target materials, and particularly discloses an indium gallium titanium oxide target material and a preparation method and application thereof. The indium gallium titanium oxide target material is prepared from the following raw materials in parts by mass: 95 to 99 parts of indium oxide, 0.5 to 2 parts of gallium oxide and 0.6 to 3 parts of titanium dioxide. According to the preparation method, gallium oxide and titanium dioxide in a proper proportion are doped in the indium oxide-based target material, so that an oxide film prepared from the target material has excellent light transmittance on the premise of keeping relatively low resistivity of the target material, and the oxide film prepared from the target material has relatively good mechanical flexibility, and can be applied to the field of organic light-emitting devices, such as organic light-emitting devices, organic light-emitting devices, organic light-emitting devices, organic light-emitting devices, organic light-emitting devices and organic light-emitting devices. And the method can be better applied to flexible OLEDs. The invention also provides a preparation method of the indium gallium titanium oxide target material.

The invention provides a positive pole piece, a preparation method thereof and a lithium ion battery. The positive pole piece comprises a positive current collector and a negative current collector, the first active coating is arranged on the surface of at least one side of the positive electrode current collector; the raw materials of the first active coating comprise a first main material, a first conductive agent and a low-swelling binder; the second active coating is arranged on the surface of one side, relatively far away from the positive electrode current collector, of the first active coating; and raw materials of the second active coating comprise a second main material, a second conductive agent and a high-swelling binder. Different types of binders are introduced into the first active coating and the second active coating, so that the tortuosity and porosity of the pole piece are changed, the diffusion rate of lithium ions is effectively improved, the concentration polarization of the surface layer of the pole piece is reduced, and the rate and cycle performance of the battery are remarkably improved. Particularly, the positive pole piece can achieve the goal of improving the multiplying power and the cycle performance without increasing the proportion of the conductive agent.

The invention discloses composite powder with a core-shell structure and a preparation method of the composite powder. The preparation method comprises the steps of pretreatment, titanium dioxide coating treatment, plating solution treatment and silver coating treatment. The titanium dioxide coating treatment comprises the following steps: after ultrasonically stirring butyl titanate and absolute ethyl alcohol, adding dilute acid to prepare a reaction solution; nickel powder is added into the reaction liquid for a constant-temperature reaction, and titanium dioxide coated nickel powder is obtained after the reaction; the plating solution treatment comprises the steps that titanium dioxide coated nickel powder, a solvent and a dispersing agent are subjected to ultrasonic stirring and then subjected to constant-temperature stirring, a reducing agent and a sodium hydroxide solution are added, and a dispersed solution is obtained after reaction; the silver coating treatment comprises the following steps: ultrasonically stirring and dispersing silver nitrate and deionized water, and then adding a complexing agent for complexing reaction; and pouring into the dispersion solution under a stirring state, and reacting to obtain the composite powder. According to the method, the stability of the nickel powder and the compactness of the coating layer in the preparation process of the composite powder can be effectively improved, and then the conductivity of the composite powder can be improved.

The invention relates to the technical field of perovskite solar cell preparation, in particular to a bulk phase passivation perovskite light absorption layer, a solar cell and a preparation method, the bulk phase passivation perovskite light absorption layer is prepared by adopting a perovskite layer prefabricated liquid, the perovskite layer prefabricated liquid comprises (FA 0.95 MA0.05) 0.95 Cs0.05 Pb (I 0.95 Br0.05) 3 and m-F-PEACl, the molar concentration ratio of the (FA 0.95 MA0.05) 0.95 Cs0.05 Pb (I 0.95 Br0.05) 3 to the m-F-PEACl is 1.5: (0.1-1), m-F-PEACl and (FA < 0.95 > MA0. 05) < 0.95 > Cs0. 05Pb (I < 0.95 > Br0. 05) 3 are matched to form a bulk phase passivated perovskite layer, so that organic cations in the m-F-PEACl interact with uncoordinated lead ions or other defect sites in the (FA < 0.95 > MA0. 05) < 0.95 > Cs0. 05Pb (I < 0.95 > Br0. 05) 3 to form a stable complex or compound, the defect concentration in perovskite is reduced, comprehensive and effective passivation is realized, and the performance of the perovskite is improved. Therefore, the photoelectric property and the stability of the perovskite material are improved. The problem that comprehensive and effective passivation cannot be achieved through a perovskite thin film passivation method in the prior art is solved.

The invention relates to the technical field of lithium batteries, in particular to a binder composition and application thereof, a negative electrode material, a negative electrode plate and a lithium ion battery. The binder composition comprises the following components in parts by weight: 100 parts of a binder; 0.1 to 10 parts of conductor polymer; 0-20 parts of a functional polymer; the conductor polymer is selected from one or more of imine covalent organic framework polymers; the functional polymer is selected from one or more of polymers capable of forming dynamic hydrogen bonds with the binder and / or the conductor polymer. The binder composition is used for the silicon-based lithium ion battery, can maintain the complete structures of the negative electrode of the lithium ion battery and an SEI membrane, and can improve the electrochemical performance of the lithium ion battery.

The invention provides a self-supporting carbon-based material loaded with iron nanoparticles as well as a preparation method and application of the self-supporting carbon-based material, and belongs to the technical field of preparation and application of an electrocatalyst for removing nitrate in sewage. The preparation method of the self-supporting carbon-based material loaded with the iron nanoparticles comprises the following steps: providing a carbon felt subjected to acid pickling and water bath heating; the method comprises the following steps: mixing an iron precursor and urea in a solvent to obtain a mixed solution containing iron salt; and mixing the carbon felt with the mixed solution containing the iron salt, and carrying out a hydrothermal reaction to obtain the self-supporting carbon-based material loaded with the iron nanoparticles. When the iron nanoparticle-loaded self-supporting carbon-based material provided by the invention is used as a cathode for electro-catalysis of nitrate-containing wastewater, a good removal rate and ammonia nitrogen selectivity are achieved, and the catalyst can keep relatively high nitrate nitrogen removal and ammonia nitrogen production effects under the conditions of acidity, neutrality, alkalinity and different initial nitrate concentrations; the method has the advantages of high removal efficiency, good ammonia nitrogen selectivity, strong stability and the like.

The invention relates to the technical field of lithium ion batteries, and provides a lithium iron phosphate battery positive pole piece, a preparation method and a lithium ion battery. The positive pole piece of the lithium iron phosphate battery comprises a foil layer, the positive electrode coatings are coated on the front and back surfaces of the foil layer, and comprise a first positive electrode coating close to the foil layer and a second positive electrode coating far away from the foil layer; wherein the first positive electrode coating comprises a first positive electrode active material, a first conductive agent and a first binder, and the first positive electrode active material is a lithium iron phosphate material; the second positive electrode coating comprises a second positive electrode active material, a second conductive agent and a second binder, and the second positive electrode active material comprises a lithium iron phosphate material and a ternary lithium material. Through a double-layer coating technology, a ternary material with good conductivity is introduced as an outer layer, so that the conductivity of an outer layer system is improved, the resistivity of the pole piece is reduced, and the problems of large internal resistance and poor dynamic performance of a positive electrode thick coating are solved.

According to the grounding resistance reducing device of the oil-immersed transformer and the using method of the grounding resistance reducing device, the grounding resistance reducing device is arranged on one side of a body of the oil-immersed transformer, the oil-immersed transformer is provided with a grounding wire, the grounding wire is connected with a grounding electrode inserted into the ground, and a resistance reducing device is arranged over the grounding electrode. The resistance reduction device comprises a rainwater collection pool located on the ground, a conductive material chamber arranged in the rainwater collection pool and a plurality of liquid distribution pipes communicated with the rainwater collection pool, the liquid distribution pipes are inserted underground and located around the grounding electrode, a plurality of liquid outlet holes facing the grounding electrode are formed in the liquid distribution pipes, and soil monitoring units are arranged on the lower portions of the liquid distribution pipes; a first automatic discharging valve is arranged on the lower portion of the rainwater collecting pool, a water level monitoring unit is arranged in the first automatic discharging valve, the first automatic discharging valve is provided with a liquid outlet located in the lower portion, and the upper portions of the liquid distribution pipes are all communicated with the liquid outlet. Rainwater in the rainwater collecting pool is discharged through the first automatic discharging valve, and the rainwater flows to the position near the grounding electrode through the multiple liquid distribution pipes, so that the conductivity of soil is improved.

The invention discloses a lithium-doped silicon-carbon composite material, a preparation method and application, and belongs to the technical field of preparation of lithium ion battery negative electrode materials. According to the lithium-doped silicon-carbon composite material disclosed by the invention, metal lithium is doped in porous carbon, and nano silicon is deposited on the surface of the porous carbon, so that the resistivity of the composite material is reduced; the rate capability of the lithium ion battery is improved; the surface of the nanometer silicon is coated with carbon twice through passivation gas and carbon source gas, so that the defects of the surface of the nanometer silicon are reduced, and the nanometer silicon is prevented from being in direct contact with an electrolyte, thereby reducing the side reaction of a negative electrode interface of the lithium ion battery, reducing the decomposition of the electrolyte, reducing the gas production and improving the first efficiency.

The invention belongs to the technical field of semiconductor graphite materials, and particularly relates to a semiconductor graphite material and a preparation method thereof. The semiconductor graphite material comprises the following raw materials in percentage by mass: 23-33% of pitch coke powder, 23-33% of green petroleum coke powder, 5-15% of artificial graphite powder, 3-8% of natural graphite powder and the balance of modified pitch. The semiconductor graphite material disclosed by the invention has relatively high breaking strength, compressive strength, hardness and density; the prepared ceramic has low resistivity, porosity and ash content, the preparation process is simpler, and the production cost is reduced.

The invention belongs to the technical field of target material production, and discloses a ZMO target material which is prepared from zinc oxide, magnesium oxide and doped metal oxide. Wherein the doped metal oxide is selected from at least one of tantalum pentoxide, cerium dioxide, titanium dioxide, niobium pentoxide, manganese sesquioxide and chromium sesquioxide, the mass ratio of metal elements in zinc oxide to metal elements in magnesium oxide is (73-91): (9-27), and meanwhile, the metal elements in the doped metal oxide account for 1000-10000 ppm of the total mass of the metal elements in the target material. Through the design, on one hand, the relative density of the target material is improved, and on the other hand, higher carrier concentration or more excellent carrier migration capability is provided for the target material by doping the metal oxide, so that the resistivity of the target material is reduced; in addition, the invention also discloses a preparation method of the ZMO target material.

The invention discloses a preparation method of a TCO film with good electroplate liquid corrosion resistance, which comprises the following steps: weighing ABCD powder according to the mass percentage, mixing the ABCD powder, grinding, carrying out compression molding, carrying out cold isostatic pressing molding, sintering in a high-temperature atmosphere and the like to obtain a target material, and carrying out sputtering coating by using the target material through a direct-current magnetron sputtering coating machine to obtain the TCO film. The TCO thin film prepared by the method has good electroplate liquid corrosion resistance, low resistivity and good conductivity, the sheet resistance of the thin film is only slightly increased and the transmittance is only slightly reduced after the thin film is soaked for 10 minutes, and the TCO thin film shows excellent electroplate liquid corrosion resistance, is used as an electrode material of a novel crystalline silicon heterojunction solar cell and has good application prospects. The TCO thin film electroplating copper electrode is used for replacing a traditional silk-screen printing silver paste electrode, complete silver removal is achieved, and the non-silicon cost of a heterojunction cell is reduced.

The invention discloses a preparation method of low-resistivity barium titanate-based PTC (Positive Temperature Coefficient) ceramic, which comprises the following steps: by taking BaCO3, TiO2, SrCO3, CaCO3, Nb2O5, Y2O3 and MnO2 as raw materials, carrying out ball-milling mixing, drying and pre-sintering on the raw materials to obtain a calcined material; mixing the calcined material with sintering aids SiO2 and Al2O3, and carrying out secondary ball milling and secondary drying to obtain a secondary material; and mixing the secondary material with an adhesive, granulating, pressing the granulated powder into a biscuit by using a mold, and carrying out adhesive removal and sintering on the biscuit by using a high-temperature furnace to obtain the low-resistivity barium titanate-based PTC ceramic. The barium titanate-based PTC ceramic obtained by the invention has extremely low resistivity (50-60 omegamm) at room temperature, the Curie point of the barium titanate-based PTC ceramic is adjustable in the range of 80-150 DEG C, and the lift-drag ratio rhomax / rho25 exceeds 100. The barium titanate-based PTC ceramic prepared by the preparation method disclosed by the invention has extremely low room-temperature resistivity and an adjustable Curie point, and has a relatively excellent PTC effect.

The invention belongs to the technical field of aqueous zinc metal batteries, provides a composite negative electrode material for an aqueous zinc metal battery and a preparation method thereof, and aims to improve the cycle performance of the aqueous zinc metal battery and promote commercial application of the aqueous zinc metal battery. The composite negative electrode material is of a three-layer coating structure and is composed of zinc powder, carbon balls and bismuth nanosheets, the carbon balls are of an egg yolk shell structure, the zinc powder is coated with the carbon balls, and the surfaces of the carbon balls are coated with the bismuth nanosheets; the unique structure of the composite negative electrode not only can provide a rich continuous interface to promote efficient transfer of electrons, but also can reduce volume expansion and shrinkage generated in the repeated electroplating / stripping process of zinc metal, so that the electric contact loss of the zinc negative electrode is effectively inhibited; and the outer bismuth nanosheet not only can inhibit the hydrogen evolution reaction of a zinc metal / electrolyte interface, but also can enhance the transmission of ions in the electrochemical process, and induce the Zn (002) crystal face to be deposited on the surface of the electrode, so that the formation of zinc dendrites can be effectively inhibited through the plane deposition mechanism.

The invention discloses a resin-based hard carbon composite material and application thereof in button type half-cell preparation. The method comprises the following steps: melting phenol, and adding a formaldehyde solution to prepare a mixed solution A; dispersing the carbon nano tube powder and hexadecyl trimethyl ammonium bromide in pure water, and grinding to obtain carbon nano tube dispersed slurry B; and adding the carbon nanotube dispersion slurry B into the mixed solution A to obtain a mixed solution C, adjusting the pH value to prepare a phenolic resin precursor solution, carrying out cross-linking curing to prepare a phenolic resin cured precursor, carrying out mechanical grinding, and putting the phenolic resin cured precursor into a tubular furnace to finally prepare the resin-based hard carbon composite material. Conductive carbon is introduced to the condensation polymerization end of phenol and formaldehyde, a communicated conductive network is formed in the composite material by regulating and controlling the material composition, the electron transmission distance between particles is shortened, the intrinsic conductivity of original resin carbon is improved, and the composite material has the advantages of high capacity, high first efficiency, high magnification and low ash content; wide application prospects are realized in the field of lithium ion battery negative electrode materials.

The invention belongs to the technical field of ceramic preparation, and particularly relates to a tin oxide ceramic material and a preparation method and application thereof. According to the invention, oxygen vacancies are introduced into the conductive doped oxide, so that the conductivity of tin oxide is greatly improved; the sintering aid promotes liquid-phase sintering of the biscuit in the sintering process, so that the problem of sintering difficulty caused by volatilization of tin oxide at a high temperature of 1200 DEG C is solved, particle rearrangement and mass transfer processes are greatly promoted, and sintering densification of tin oxide is promoted; due to the introduction of gallium oxide, not only is pinning at the tin oxide grain boundary to prevent grain growth and obtain uniform and fine grain size, but also the conductivity of the ceramic material is further improved. The tin oxide ceramic material obtained by the invention has the characteristics of high density, low resistivity and uniform and fine crystal grains. Meanwhile, the preparation process is simple and suitable for industrial production.

The invention discloses a preparation method of a sodium manganese titanium phosphate positive electrode material for a sodium-ion battery and a vehicle, belongs to the technical field of synthesis of the sodium-ion battery positive electrode material, and particularly relates to the preparation method of the sodium manganese titanium phosphate positive electrode material for the sodium-ion battery. The preparation method comprises the following steps: mixing a sodium source, a phosphorus source, a carbon source, a titanium source, a manganese source and a high-entropy metal source, then adding a slurry binder, stirring and dispersing at a high speed, and carrying out sanding treatment, spray drying and high-temperature calcination to prepare the sodium titanium manganese phosphate positive electrode material for the sodium-ion battery. The slurry binder at least comprises a polyarylene ether nitrile derivative, and the polyarylene ether nitrile derivative has a sulfur element and a cyano group. The invention provides the preparation method of the sodium manganese titanium phosphate positive electrode material for the sodium-ion battery, which is high in first cycle reversible capacity, low in resistivity, long in cycle life and excellent in rate capability, and the prepared sodium manganese titanium phosphate positive electrode material for the sodium-ion battery is applied to preparation of vehicles.

The invention relates to a shield gate trench MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) device structure and a manufacturing method thereof. The structure comprises a substrate and an epitaxial layer, the epitaxial layer comprises a first epitaxial layer and a second epitaxial layer which are sequentially grown on the substrate; at least one MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) device unit is arranged in the epitaxial layer; the MOSFET device unit comprises two groups of first grooves and a second groove positioned between the two groups of first grooves; a shield gate structure is arranged in the first groove, and an active polycrystalline silicon structure grows in the second groove; body regions are doped on the two sides of the first groove and between the first groove and the second groove. Under the requirement of the same breakdown voltage, the doping concentration of the second epitaxial layer can be increased, so that the resistivity is reduced, the on-resistance Ron is reduced, and the power loss of the MOSFET device can be reduced.

The invention discloses a preparation method of a negative pole piece of a lithium ion battery, which is used for solving the technical problem that the overall performance of the battery is influenced due to the increase of the resistance of the negative pole piece caused by the adsorption of CMC (Carboxymethyl Cellulose) on the surface of a negative active material in the preparation process of the existing negative pole piece. The method specifically comprises the following steps: uniformly stirring a negative electrode active material, SBR, a conductive agent and CMC to obtain negative electrode slurry; uniformly coating a negative electrode current collector with the negative electrode slurry, and performing drying, rolling and striping to obtain a negative electrode plate; and placing the negative pole piece in a high-temperature furnace, and carrying out heat preservation for a preset time according to a set temperature, so that the CMC is decomposed and carbonized at a high temperature to form a conductive structure. In the steps, after the negative pole piece is heated in the high-temperature furnace for the preset time, the CMC is decomposed and carbonized at high temperature to form a conductive structure, chain-shaped coating of the negative active material is realized, and the resistivity of the negative pole piece is greatly reduced.

The invention provides a coating composition, a preparation method, a water-based antistatic coating and application, and belongs to the field of coatings. The coating composition is prepared from the following components in parts by weight: 35 to 55 parts of water-based hydroxy acrylic resin, 0.1 to 0.3 part of amine neutralizer, 0.2 to 0.5 part of defoaming agent, 0.5 to 1 part of dispersing agent, 0.1 to 0.8 part of polysilicate magnesium aluminum, 10 to 15 parts of conductive mica powder, 20 to 30 parts of titanium dioxide, 0.5 to 1 part of silane coupling agent, 0.5 to 1 part of graphene, 0.2 to 0.5 part of thickening agent and 8 to 15 parts of solvent. According to the embodiment of the invention, the composition of the coating composition is reasonably designed, so that the adhesive force and the antistatic force of a coating layer formed by the coating on the CFRTP surface are improved at the same time.

The invention belongs to the technical field of conductive materials, and particularly discloses graphene conductive paste and a preparation method and application thereof. The graphene conductive paste is prepared from the following raw materials in parts by weight: 1 to 10 parts of graphene, 0.5 to 10 parts of conductive carbon black, 0.5 to 1 part of a dispersing agent, 0.5 to 2 parts of a stabilizer, 80 to 90 parts of a solvent, 0.5 to 1.5 parts of a surfactant, 1 to 5 parts of a modified silane coupling agent and 0.5 to 1 part of an adhesive, the molecular structure of the modified silane coupling agent contains fluorine element and phosphorus element, and also contains phenolic hydroxyl group, and various groups have synergistic interaction, so that the performance of the graphene conductive paste is improved together; the invention also discloses a preparation method and application of the graphene conductive paste. The graphene conductive paste provided by the invention has excellent conductivity, cohesiveness, corrosion resistance, dispersity and thermal stability, and can be widely applied to preparation of lead-acid batteries, sodium-ion batteries and lithium-ion batteries.

The invention discloses a preparation method and application of a resin-based hard carbon composite material, the preparation method comprises the following steps: melting phenol, adding a formaldehyde solution, adding carbon nanotube powder, and adjusting the pH value to 8-10 by using triethylamine to prepare a phenolic resin precursor solution; carrying out cross-linking curing reaction on the phenolic resin precursor solution to obtain a phenolic resin cured precursor; and mechanically grinding the phenolic resin curing precursor, and putting the phenolic resin curing precursor into a tubular furnace to finally prepare the resin-based hard carbon composite material with the conductivity of more than 30S / cm. Conductive carbon is introduced to the condensation polymerization end of phenol and formaldehyde, a communicated conductive network is formed in the composite material by regulating and controlling the material composition, the electron transmission distance between particles is shortened, the intrinsic conductivity of original resin carbon is improved, and the composite material has the advantages of high capacity, high first efficiency, high magnification and low ash content; wide application prospects are realized in the field of lithium ion battery negative electrode materials.

The embodiment of the invention relates to the technical field of monocrystalline silicon preparation, and provides a crystal pulling control method which at least can improve the axial resistivity uniformity of a monocrystalline silicon rod. The control method comprises the following steps: acquiring a prediction curve, wherein the prediction curve is expressed as a change curve of resistivity corresponding to different equal-diameter lengths of a silicon single crystal rod comprising a first dopant; obtaining a preset isodiametric slope table based on the prediction curve, the preset isodiametric slope table and corresponding preset process parameters, wherein the preset process parameters comprise a power ratio of the set power of the upper heater to the set power of the lower heater; the preparation method comprises the following steps: preparing a target monocrystalline silicon rod, adding a silicon material and a first dopant into a crucible, sequentially carrying out a melting process, a seeding process, a shouldering process and an equal-diameter process to obtain an initial monocrystalline silicon rod, adjusting process parameters of the equal-diameter process according to preset process parameters, and after the equal-diameter length of the initial monocrystalline silicon rod reaches a target length, carrying out continuous casting on the target monocrystalline silicon rod to obtain the target monocrystalline silicon rod. And entering an ending process to obtain the target single crystal silicon rod.

The invention relates to a composite resistance reducing agent and a preparation method and application thereof, and belongs to the technical field of grounding materials of electric power protection systems. The composite resistance reducing agent provided by the invention is prepared from the following components in parts by weight: 20 to 40 parts of bentonite, 20 to 30 parts of conductive cement, 20 to 30 parts of graphite and 5 to 15 parts of conductive mica powder. The bentonite, the conductive cement, the graphite and the conductive mica powder are reasonably compounded, so that the composite resistance reducing agent has good water absorption and water retention, the lower resistivity of the resistance reducing agent is kept for a long time, meanwhile, the composite resistance reducing agent can well permeate and diffuse into surrounding soil, and long-term stable work of the composite resistance reducing agent can also be guaranteed in different climatic environments. The composite resistance reducing agent does not contain inorganic salt, does not corrode various electrode materials, is non-toxic and does not have negative influence on the surrounding environment.

The invention discloses a silicon carbide ceramic material and a preparation method thereof, and relates to the technical field of ceramics. When the silicon carbide ceramic material is prepared, firstly, apricot shell carbon, nano silicon dioxide and sodium salt are mixed and calcined in a nitrogen atmosphere, and a modified silicon carbide composite nanowire is prepared; modifying the modified silicon carbide composite nanowire and praseodymium powder by a molten salt method to prepare a praseodymium modified silicon carbide composite nanowire; liquid polycarbosilane, the praseodymium modified silicon carbide composite nanowire, a modification additive, silicon carbide particles and a sintering additive are subjected to wet ball milling, mixing and curing, and then composite sintering powder is prepared; and sintering the composite sintered powder by a spark plasma sintering method, and then annealing in an argon atmosphere to prepare the silicon carbide ceramic material. The silicon carbide ceramic material prepared by the invention has the advantages of high thermal conductivity, electromagnetic shielding, high strength and high compactness.

The present invention belongs to the technical field of electrode material preparation, and specifically relates to a lithium iron phosphate positive electrode material, a preparation method and an application thereof. The K value of the lithium iron phosphate positive electrode material is ≤1, and K is calculated by the grain size and b-axis length of the lithium iron phosphate positive electrode material. The positive electrode material has excellent properties such as low resistivity, high conductivity, high compaction density and high capacity. The inventor found in the research process that the lithium iron phosphate positive electrode material K≤1 can ensure that it has excellent properties such as high conductivity, low resistivity, high compaction density and high capacity. The powder resistivity of the lithium iron phosphate positive electrode material is less than 10Ω·cm, and the compaction density is greater than 2.2g / cm 3 , 0.1C discharge capacity is greater than 160mAh / g, 1C discharge capacity is greater than 150mAh / g, it has the advantage of high capacity.