616 results about "Nitrogen doping" patented technology

The invention provides a preparation method of a porous carbon-silicon composite negative electrode material of a lithium battery. The preparation method comprises the following steps: constructing a multi-stage template system; carrying out carbon precursor impregnation and gradient temperature carbonization on the multistage template system; removing the template to form a gradient porous carbon carrier; carrying out gradient temperature zone silane deposition; and plasma-assisted carbon coating and nitrogen doping are carried out. According to the method, a silicon dioxide sphere hard template is combined with cetyltrimethylammonium bromide and a block copolymer soft template to form a porous carbon carrier with a micropore-mesopore-macropore three-stage structure, and gradient distribution of silicon in porous carbon is realized by utilizing a three-temperature-zone fluidized bed reactor and a pulse type deposition technology, so that the silicon-based porous carbon composite material is obtained. The problem of volume expansion of the silicon material is effectively relieved and the material cycling stability is improved. The porous carbon-silicon composite negative electrode material prepared by the invention has high specific surface area, excellent ion transmission channel and good structural stability, and can be applied to a high-energy-density lithium ion battery.

The invention discloses a preparation process of a modified porous carbon material catalyst. The preparation process comprises the following steps: (1) mixing and calcining a biomass precursor and a template agent to prepare graded porous carbon; (2) low-frequency plasma pretreatment and high-frequency plasma fluorination modification are adopted; (3) introducing the pulse plasma into a nitrogen doping site; (4) spraying ionic liquid and activating H2 plasma to form a B / F co-doped layer; and (5) loading alloy nanoparticles such as PtRu through pulse electrodeposition. According to the obtained catalyst, biomass derived porous carbon serves as a carrier, a fluorine / nitrogen co-doped active layer is constructed on the surface of the carrier through multi-frequency plasma synergistic modification and ionic liquid auxiliary modification, superfine precious metal nanoparticles are loaded, the hydrogen evolution overpotential of the catalyst is smaller than or equal to 28 mV under the current density of 10 mA / cm < 2 >, the activity attenuation is smaller than 5% after 1000 times of circulation, and the catalyst has a good catalytic activity. The water electrolysis hydrogen production device is suitable for a large-scale water electrolysis hydrogen production device.

The invention discloses a silicon-carbon negative electrode material, a preparation method thereof and a lithium ion battery, and relates to the technical field of lithium ion battery negative electrode materials. The material sequentially comprises a porous silicon core, a transition layer and a shell from inside to outside, the transition layer is a nitrogen-doped SiC / C composite layer, the shell comprises a graphene / carbon nanotube skeleton and MXene quantum dots, the MXene quantum dots are embedded in the graphene / carbon nanotube skeleton, boric acid ester bonds exist between carbon nanotubes and graphene, and the MXene quantum dots are embedded in the graphene / carbon nanotube skeleton. The silicon-carbon negative electrode material is based on dual-network dynamic bonding and stress gradient regulation and control, the cycle performance of the material can be remarkably improved, and the service life of the material can be remarkably prolonged.

The invention discloses a silicon-carbon material as well as a preparation method and application thereof. The silicon-carbon material comprises nitrogen-doped porous carbon and an amorphous carbon layer coating the nitrogen-doped porous carbon, and pores of the nitrogen-doped porous carbon are filled with boron-doped nano silicon. The nitrogen-doped porous carbon improves the affinity of silane gas while improving the electron conductivity, a high-conductivity and high-density silicon-carbon composite structure is realized, the boron-doped nano silicon and the nitrogen-doped porous carbon form a nano heterojunction site, and the migration rate of lithium ions is improved, so that electrochemical reaction kinetics is improved, and the electrochemical performance of the lithium ion battery is improved. The material has the advantages of high rate and long cycle performance.

The invention discloses a silk protein-MXene composite film and a preparation method thereof. The silk protein-MXene composite film sequentially comprises a conductive surface layer, a porous response layer and a supporting bottom layer from top to bottom, the invention relates to the technical field of composite films. According to the fibroin-MXene composite film and the preparation method thereof, a three-layer gradient structure is formed by the conductive surface layer, the porous response layer and the supporting bottom layer, good conductivity and electromagnetic shielding effectiveness are ensured by utilizing oriented arrangement of MXene of the conductive surface layer, gallic acid and MXene form a hydrogen bond network, and nitrogen-doped carbon quantum dots coat the surface of MXene to form a physical barrier, so that the electromagnetic shielding effect is improved, and the electromagnetic shielding effect is improved. Through double oxidation resistance of gallic acid and nitrogen-doped carbon quantum dots, a sponge body structure formed by the porous response layer is matched to endow the composite film with high-sensitivity response to external stimulation, the supporting bottom layer is crosslinked by hexamethylene diisocyanate and enhanced by nanocellulose, the tensile strength is improved, and the tensile strength of the composite film is improved. And the contradiction between the mechanical property and the conductivity of the traditional composite film is effectively solved.

The invention provides a super-hydrophobic passion fruit peel carbon aerogel VOCs adsorbent based on low-temperature plasma synergistic nitrogen doping modification and a preparation method thereof, and relates to the technical field of VOCs adsorbents. The super-hydrophobic passion fruit peel carbon aerogel VOCs adsorbent based on low-temperature plasma synergistic nitrogen doping modification is prepared by crushing passion fruit peel, mixing the crushed passion fruit peel with a nitrogen-containing compound to form gel, performing low-temperature plasma modification, performing freeze drying, performing high-temperature carbonization, and performing water washing and drying. The adsorbent is spherical, and the water contact angle is 115.8 degrees to 152.4 degrees. The adsorbent disclosed by the invention has the advantages of super hydrophobicity, high specific surface area, developed microporous structure, excellent VOCs adsorption performance, broad-spectrum adsorption capacity, good reusability and mechanical strength, the preparation method is simple in process, green and environment-friendly, low in cost and good in universality, a new technical scheme is provided for VOCs treatment in a high-humidity environment, and the adsorbent has a good application prospect.

An electrode structure for a solid-state or semi-solid-state battery is provided in which NCM electrode particles coated with an interphase layer and a nitrogen-containing carbon layer are disposed. [Solution] The NCM electrode particles comprise NCM (nickel-cobalt-manganese oxide) particles (15), primary particles (30) that coat the outer surfaces of the NCM particles, an interphase layer (16) that includes a glass phase layer (241) and a plurality of ceramic particles (242), and a nitrogen-containing carbon layer (35) that coats the exterior of the primary particles. Nitrogen-doped carbon molecules in the nitrogen-containing carbon layer aid in the conduction of electrons and lithium ions, modifying the electrical potential of the NCM particles. The nitrogen-containing carbon layer is formed by coating the surfaces of the primary particles with a nitrogen-containing polymer material and calcining the material in an inert atmosphere. Conjugated bonds are formed between the carbon and nitrogen, modifying the energy band structure, reducing the energy required for electrons to transition to the conduction band, and improving overall electronic conductivity.

The invention discloses a silicon / graphite / carbon-aluminum oxide composite negative electrode material and a green preparation method thereof, and belongs to the technical field of lithium ion batteries. Aiming at the problems of high volume expansion rate and poor cycling stability of a silicon-based negative electrode and high cost of a traditional process, the invention innovatively provides the following scheme: 1) waste photovoltaic silicon wafer ball-milling liquid and waste graphite are taken as core raw materials, and resource recycling is realized; (2) phenolic resin and chitosan are adopted as double carbon sources, a nitrogen-doped carbon layer (the nitrogen content is 3-5 wt.%) is formed through pH-induced self-assembly, and the conductivity and the Li < + > diffusion rate are synchronously improved; and 3) aluminum nitrate is introduced for pyrolysis to generate 2-5nm aluminum oxide for doping, so that the side reaction of the electrolyte is inhibited, and the volume expansion of silicon is relieved (the expansion rate is less than or equal to 120%). The preparation process comprises the steps of silicon / graphite dispersion, double-carbon-source compounding, ammonia water regulation and control precipitation and gradient calcination. Experiments show that the specific capacity of the optimized material under the current of 0.5 A / g reaches more than 800mAh / g, the 100-time cycle capacity retention ratio is more than 98%, the 1000-time cycle capacity retention ratio is more than 80%, the reversible specific capacity under the multiplying power of 3A / g is more than 550mAh / g, and the raw material cost is reduced by 40%. The invention has the advantages of high capacity, long service life, environmental protection and economy, and provides an innovative solution for the fields of power batteries and energy storage.

The present invention belongs to the technical field of battery materials, and particularly relates to a composite phosphate-based positive electrode material, and a preparation method therefor and the use thereof. The composite phosphate-based positive electrode material comprises a phosphate-based active core, wherein the outer surface of the phosphate-based active core is sequentially coated with a carbon coating layer, a nitrogen-doped carbon coating layer and a nitrogen-phosphorus co-doped carbon coating layer from inside to outside, wherein the carbon coating layer can improve the electronic and ionic conductivity of the composite positive electrode material, and optimize the particle size and morphology of the composite positive electrode material. The nitrogen-doped carbon coating layer improves the consistency and integrity of coating; and nitrogen-atom-doped carbon further enhances the electronic conductivity and lithium-ion diffusion of the carbon coating layer. Electron-rich clouds of P and N atoms in the nitrogen-phosphorus co-doped carbon coating layer can provide a rich conductive network, mutual contact is formed among different particles to form a series network, thus promoting the interfacial electron transport of the composite material during a charging and discharging process, and improving the cycling and rate performance of the composite phosphate-based positive electrode material during the charging and discharging process.

The invention provides a negative electrode active material and a preparation method thereof, a negative electrode for a sodium ion battery, the sodium ion battery and an electric device. The negative electrode active material comprises a nitrogen-doped carbon sphere matrix and manganese monoxide embedded into the nitrogen-doped carbon sphere matrix, the average particle size of the manganese monoxide is 1.5 nm to 2.5 nm. In the negative electrode active material, the quantum-dot-level MnO is embedded into the nitrogen-doped carbon sphere matrix, so that a tight embedded structure (non-surface loading) of the quantum-dot-level MnO and the nitrogen-doped carbon spheres can be realized, volume expansion when sodium ions are embedded and removed is effectively relieved, and an efficient electron / ion transmission channel is provided. Meanwhile, the quantum dot-level MnO has a larger specific surface area, and provides more adsorption sites with the nitrogen-doped carbon, so that the composite material shows a pseudocapacitance-dominated sodium storage behavior, and is endowed with ultrahigh rate capability and ultra-long cycle life.

The invention discloses a composite positive electrode material which comprises a layered oxide and a coating layer, the general formula of the layered oxide is NaMe < 1-x > Al < x > O < 2 >, Me is one or more of nickel, iron, manganese and cobalt, and x is greater than 0; the coating layer is coated outside the layered oxide, the coating layer sequentially comprises a first coating layer, a second coating layer and a third coating layer from inside to outside, the first coating layer is titanium aluminum carbide, the second coating layer is titanium nitride, the third coating layer is nitrogen-doped polymeric porous carbon, and the composite positive electrode material forms an Al-N bond. The invention also discloses a positive plate with the composite positive electrode material and a sodium ion battery. The cyclic expansion rate can be effectively controlled while the cyclic electrical performance is guaranteed.

The invention relates to a modified graphite felt, a preparation method thereof and application of the modified graphite felt in a vanadium redox flow battery, and belongs to the technical field of redox flow battery electrodes. The method comprises the following steps: mixing a graphite felt with a mixed solution, and carrying out thermal reaction to obtain a metal organic framework two-dimensional nanosheet loaded graphite felt; sintering the graphite felt loaded by the metal organic framework two-dimensional nanosheet to obtain a modified graphite felt; wherein the mixed solution comprises a nitrogen-containing organic ligand and a metal salt. According to the modified graphite felt, the surface of the modified graphite felt is coated with a layer of metal nitrogen-carbon two-dimensional nanosheets, the metal organic framework two-dimensional nanosheets are formed by the coordination reaction of the nitrogen-containing organic ligands and the metal salts, metal is uniformly dispersed in the organic framework two-dimensional nanosheets, and then the metal is uniformly dispersed in the metal nitrogen-carbon two-dimensional nanosheets; therefore, numerous metal active sites are uniformly distributed on the surface of the obtained modified graphite felt, nitrogen element doping is formed at the same time, and the electrochemical performance of the modified graphite felt electrode is improved.

The invention relates to the technical field of agricultural application of nano materials, and discloses a preparation method and application of a photosynthetic accelerant containing carbon quantum dots. Urea and citric acid are adopted as raw materials, and the nitrogen-carbon molar ratio and hydrothermal reaction parameters are optimized, so that efficient doping of nitrogen and accurate regulation and control of the particle size are achieved, and the photosynthetic accelerant containing the carbon quantum dots is obtained. The nitrogen-doped carbon quantum dot photosynthetic promoter with excellent upconversion performance is successfully synthesized, the promoter has good water solubility and biocompatibility, the photosynthetic efficiency of plants can be greatly improved within the concentration range of 0-100 mg / L, a safe application window is defined, and by establishing foliage spraying and water planting dual-mode application specifications, the application range of the nitrogen-doped carbon quantum dot photosynthetic promoter is widened, and the application range of the nitrogen-doped carbon quantum dot photosynthetic promoter is widened. The problems that current crops are insufficient in solar spectrum utilization and low in light energy conversion efficiency are solved in a targeted manner by utilizing an ultraviolet light-photosynthetically active radiation conversion function mediated by the carbon quantum dots and combining the targeted enrichment permeation characteristic of the carbon quantum dots in chloroplast.

The invention relates to a composite solid-state electrolyte membrane and a preparation method thereof, a lithium ion battery and an electric device, the composite solid-state electrolyte membrane comprises a lithium phosphorus oxygen nitrogen solid-state electrolyte, the general formula of the lithium phosphorus oxygen nitrogen solid-state electrolyte is LixPOyNz, x is greater than 2.7 and less than or equal to 3, zlt; 0.45, 3 < (y + z) < 4; along the thickness direction of the solid electrolyte membrane, the nitrogen doping ratio of the lithium-phosphorus-oxygen-nitrogen solid electrolyte in the composite solid electrolyte membrane is gradually increased, and the corresponding oxidation stoichiometric number is gradually reduced. According to the composite solid electrolyte membrane, the capacity retention ratio, the cycling stability and the safety of the lithium ion battery are improved.

The invention provides a preparation method of a gate oxide layer and a gate, and the method comprises the steps: carrying out the rapid thermal annealing treatment of a silicon-based substrate in a nitrogen-containing gas atmosphere, which belongs to a non-destructive nitrogen doping mode, and carrying out the nitrogen pre-doping on the surface of the silicon-based substrate, so as to reduce the doping amount needed by the subsequent plasma nitrogen doping; therefore, the damage of the plasma nitrogen doping process to the SiON gate oxide layer is reduced, and the interface defect between the SiON gate oxide layer and the silicon-based substrate interface is reduced. Besides, after the nitrogen pre-doped layer is formed, the thermal oxidation process is carried out on the silicon-based substrate to form the silicon dioxide gate oxide layer, so that the damage to the SiON gate oxide layer film is reduced, and the interface defect between the SiON gate oxide layer and the silicon-based substrate interface is further reduced; moreover, the laser rapid annealing treatment can remove the intrinsic oxide layer on the surface of the SiON gate oxide layer, repair the damage to the crystal lattice of the SiON gate oxide layer caused by the plasma nitrogen doping treatment process, improve the film quality and repair the interface.

The invention discloses a high-voltage single-crystal positive electrode material as well as a preparation method and application thereof, and belongs to the technical field of lithium ion batteries. The preparation method comprises the following steps: by taking MOFs (Metal Organic Frameworks) with a porous structure as a template, loading a ternary precursor in pore channels of the template by adopting a solvothermal method to prepare loaded MOFs; mixing the loaded MOFs with a lithium source, carbonizing and calcining in an inert atmosphere for high-temperature solid-phase reaction, carbonizing the template to form a nitrogen-doped porous carbon skeleton, and converting the ternary precursor into single-crystal NCM particles to prepare a calcined product; sequentially carrying out acid pickling, drying and airflow crushing treatment on the calcined product to obtain a composite material; the composite material is sequentially subjected to multi-section penetration type dry coating and sintering treatment, the high-voltage single-crystal positive electrode material is prepared, and the high-voltage single-crystal positive electrode material can balance the capacity, the cycle life and the safety under high voltage.

The invention relates to the technical field of power cables, in particular to a cross-linked polyethylene insulated power cable wrapped by a high-water-resistance buffer layer and a preparation method of the cross-linked polyethylene insulated power cable wrapped by the high-water-resistance buffer layer, and the cross-linked polyethylene insulated power cable is prepared from the following raw materials in parts by weight: 100 parts of ethylene-vinyl acetate copolymer; 15 to 25 parts of conductive carbon black; 20 to 30 parts of sodium polyacrylate; and 10 to 15 parts of nano montmorillonite. Through the high-water-resistance buffer layer and innovative process design, the problems existing in a traditional cable are solved, and the water-resistance layer effectively blocks a water permeation path through composite water absorption and a nano barrier; nitrogen doping and dispersion optimization of conductive carbon black ensure the stability of resistivity; a plasma interface activation and microcapsule cross-linking technology improves interlayer bonding force and cross-linking uniformity, gradient degassing and low-temperature cross-linking are adopted in the preparation process, the production cycle is shortened, energy consumption is reduced, meanwhile, material degradation is avoided, the cable has high water resistance and long service life, and reliability and safety of power grid operation are remarkably improved.

The invention relates to the technical field of lithium ion batteries, in particular to a chromium-molybdenum double-doped lithium iron phosphate material as well as a preparation method and application thereof. The preparation method is used for solving the problems of low capacity, low electronic conductivity and poor cycling stability of the existing lithium iron phosphate material. According to the preparation method, chromium-molybdenum is doped into lithium iron phosphate, and the bond energy of a Cr-O bond and a Mo-O bond is stronger than that of a Fe-O bond, so that the dissolution loss of Fe < 2 + > in long-term circulation is reduced, and the battery capacity and the intrinsic electron conductivity of the material are improved; lithium iron phosphate is coated with nitrogen-doped carbon nanotubes, and nitrogen is doped in graphite crystal lattices of the carbon nanotubes, so that additional free electrons are provided, the intrinsic conductivity is improved, the resistance is reduced, the rate capability is improved, and the cycle life is prolonged; the polyaniline coating layer forms a barrier layer on the surface of the lithium iron phosphate particles, so that the cycle performance and the battery capacity are improved; the three components cooperate to improve the capacity, conductivity, rate capability and cycling stability of the material.

The invention provides a phosphorus emitter passivation structure and a preparation method thereof, the passivation structure comprises a phosphorus emitter, the phosphorus emitter comprises silicon, phosphorus, hydrogen, carbon and / or nitrogen, the surface of the phosphorus emitter is provided with a nano silicon oxide layer, the phosphorus emitter comprises an electric injection region and a doped region, the electric injection region is provided with a conductive layer at a corresponding position, and the doped region is provided with a conductive layer at a corresponding position. The conductive layer is used for being connected with a metal electrode, a passivation anti-reflection layer is arranged at the corresponding position of the doped region, and the carbon and / or nitrogen concentration of the electric injection region is higher than that of the electric injection region. Partitioned passivation is performed on the surface of the phosphorus emitter, and carbon and / or nitrogen atoms are introduced into the doped region, so that the interface passivation effect is improved; the electric injection region is not subjected to carbon and nitrogen doping and is not provided with a passive film, so that the influence of passivation on the contact resistivity is reduced; a conductive channel is introduced into the electric injection region for electric injection, so that the defect state of the phosphorus emitter can be further eliminated, and the recombination current is reduced.

The invention belongs to the technical field of air purification, and discloses a nitrogen-doped MOF derived hollow porous carbon-rare earth metal doped MnO2-graphene aerogel composite material as well as a preparation method and application thereof. The preparation method provided by the invention comprises the following steps: taking a nitrogen-containing organic heterocyclic ligand, a nitrogen doping agent, a non-noble metal salt compound and chitosan, carrying out a first hydrothermal reaction, carrying out tannic acid etching and first calcination treatment, carrying out MnO2 in-situ growth on the obtained nitrogen-doped MOF derived hollow porous carbon material, and introducing a rare earth metal salt compound to obtain the nitrogen-doped MOF derived hollow porous carbon material. And finally, taking the obtained nitrogen-doped MOF derived hollow porous carbon-rare earth metal doped MnO2 composite material, graphene oxide and a reducing agent to carry out second hydrothermal reaction, ethanol soaking, freezing and freeze-drying treatment to obtain the nitrogen-doped MOF derived hollow porous carbon-rare earth metal doped MnO2 composite material. The nitrogen-doped MOF-derived hollow porous carbon-rare earth metal doped MnO2-graphene aerogel composite material has excellent adsorption and catalytic degradation activity on TVOC (Total Volatile Organic Compounds) such as formaldehyde and the like, and the composite material has a good application prospect in air purification.

The invention belongs to the technical field of lithium ion negative electrode materials, and particularly relates to a graphite negative electrode material and a preparation method thereof. The graphite negative electrode material comprises: (1) a three-dimensional porous graphite sheet layer matrix; (2) a nitrogen-doped amorphous carbon layer coated on the surfaces of the graphite particles, wherein the nitrogen element exists in the form of pyridine nitrogen and graphite nitrogen; and (3) after the material is subjected to CO2 atmosphere heat treatment, an aperture micropore structure is formed on the surface. The preparation method comprises the following steps: (1) carbonizing raw materials; (2) crushing treatment; (3) wrapping and granulating; (4) high-temperature treatment; and (5) performing subsequent treatment. According to the invention, the interface stability is obviously improved, the ion diffusion kinetics is optimized, the cycle life of the battery is obviously prolonged, the uniformity and process stability of the coating layer are improved, the energy consumption of high-temperature treatment is reduced, and the comprehensive performance and suitability of the battery are obviously optimized by reasonably controlling the capacity ratio of the positive electrode and the negative electrode and the content of a specific additive in the electrolyte.

This invention discloses a method for preparing a nitrogen-doped titanium dioxide and carbon hollow sphere heterojunction photocatalyst, comprising the following steps: 1) preparing a carbon hollow sphere core-shell structure sample based on melamine-formaldehyde nanospheres; 2) preparing a TiO2@carbon core-shell structure sample using the carbon hollow sphere core-shell structure and tetrabutyl titanate as the reaction system; 3) using a one-step method to simultaneously dope nitrogen into the TiO2@carbon core-shell structure to form an N-TiO2@N-doped carbon hollow sphere heterojunction. This invention provides a method for preparing a nitrogen-doped titanium dioxide@carbon hollow sphere heterojunction photocatalyst and its application. This method achieves uniform nitrogen doping and effective composite of TiO2 and carbon hollow spheres through specific steps, and the prepared photocatalyst exhibits excellent photocatalytic performance under both visible and ultraviolet light.

The invention belongs to the technical field of preparation of wave-absorbing materials, and particularly relates to a cobalt-based nitrogen-doped carbon nano composite material with a hollow cubic structure as well as a preparation method and application thereof. Comprising the following steps: taking ZnCo-ZIF with a nano cubic structure as a core, coating ZnCo-ZIF with polydopamine by adopting a precipitation method to form a precursor with a core-shell structure, and carbonizing the precursor at 800-900 DEG C to obtain the cobalt-based nitrogen-doped carbon nano composite material with the hollow cubic structure. According to the invention, the dielectric loss capability can be enhanced by using the conductivity and interface polarization effect of the coated carbon layer, and the Co particles introduce strong magnetic loss; meanwhile, due to interface polarization caused by abundant heterogeneous interfaces existing between the Co particles and the coating carbon layer, between the magnetic particles and the carbon nanotubes and between the carbon matrix and the carbon nanotubes in the composite material, the impedance matching characteristic can be improved, and high reflection loss and wide effective absorption bandwidth can be achieved under the low matching thickness.

The invention discloses a biomass nitrogen-doped derivative porous carbon material and a preparation method and application thereof, and belongs to the technical field of photo-thermal atmospheric water catching.The preparation method comprises the following steps that a carbon source and a nitrogen source are put into water to be subjected to an ultrasonic reaction, a reactant is subjected to hydrothermal treatment, and a solid product is obtained; carrying out steam etching and high-temperature annealing treatment on the solid product and metal salt in an inert atmosphere, and then sequentially carrying out acidizing treatment, grinding and drying to prepare the biomass nitrogen-doped derived porous carbon material. The biomass nitrogen-doped derivative porous carbon material prepared by the method has a rich pore structure and efficient adsorption-desorption performance, can replace an expensive MOFs material, optimizes the preparation path, improves the nitrogen doping efficiency and the material stability, remarkably reduces the cost and the environmental burden while ensuring the excellent atmospheric water collection performance, and has a wide application prospect. And the method shows more excellent industrialization prospects and sustainable development values.

The invention discloses a nitrogen-doped multilayer rose-shaped hard carbon material as well as a preparation method and application thereof, and belongs to the technical field of battery materials. A precursor of the nitrogen-doped multi-layer rose-shaped hard carbon material is prepared by adopting a solid-liquid self-assembly method, and then the precursor is calcined, so that the final nitrogen-doped multi-layer rose-shaped hard carbon material can be obtained. The prepared nitrogen-doped porous carbon material has more mesopores and defects, is unique in structure and uniform in shape, and can be used as a sodium ion battery negative electrode material. The nitrogen-doped multilayer rose-shaped hard carbon material prepared by the invention is a material with immunity to environmental influence, belongs to a mesoporous carbon material with stable chemical components and controllable shape in the porous field, has the advantages of regular structure, relatively good stability and the like, and has the properties of high capacity, good rate and the like as a negative electrode material.

The invention relates to the technical field of batteries, in particular to a low-hydrogen-evolution graphene material for a lead-acid battery and a preparation method thereof.The method comprises the steps that firstly, ethidene diamine is grafted to the surface of graphene oxide through a carbodiimide / active ester method, and aminated graphene is obtained; performing heat treatment in a nitrogen / ammonia gas atmosphere to realize nitrogen doping; compounding with titanium dioxide, and carrying out hydrothermal reaction to form a stable structure; then, sequentially grafting imidazolium silane and perfluorodecyl silane to carry out hydrophobic modification; and finally, stabilization and low-temperature re-nitridation curing are carried out through titanium tetrabutoxide. The graphene material prepared by the method endows the battery with excellent performance, and is low in direct-current internal resistance and high in capacity retention ratio.

The invention discloses a preparation method and application of nickel-cobalt bimetallic phosphide for in-situ growth of nitrogen-doped carbon nanotubes. The preparation method comprises the following steps: preparing a graphene oxide dispersion liquid; sequentially adding a cobalt source, a nickel source, a segmented copolymer, a phosphorus source and a nitrogen source into the graphene oxide dispersion liquid, and uniformly mixing to obtain a mixed solution; drying the mixed solution to obtain a precursor; and annealing the precursor in an inert atmosphere to obtain the product. According to the nitrogen-doped carbon material coated phosphide nano-particle composite material and the preparation method thereof, by regulating and controlling the ratio of Ni to Co, a carbon source grows on graphene in situ to form a carbon nano-tube, nickel-cobalt bimetal phosphide nano-particles are uniformly distributed on a nitrogen-doped carbon material to form the nitrogen-doped carbon material coated phosphide nano-particle composite material, and the nitrogen-doped carbon material coated phosphide nano-particle composite material is used as a modified diaphragm material of a lithium-sulfur battery. The preparation method disclosed by the invention has the advantages of mild reaction conditions and easiness in amplification and regulation, and the prepared composite material has a relatively high specific surface area and can be applied to the field of energy sources, especially the field of lithium-sulfur batteries.

The present invention discloses a negative electrode porous carbon material and a preparation method thereof, belonging to the technical field of negative electrode materials for sodium ion batteries. The carboxyl groups of acrylic acid react with the carboxyl groups of 2-hydroxyaniline, and the remaining hydroxyl groups combine with silanol groups generated by hydrolysis of 3-mercaptopropyltrimethoxysilane. Sulfonic acid-modified acrylic acid / aniline is obtained under the action of hydrogen peroxide. After calcination, sulfur- and nitrogen-doped conductive hollow carbon spheres are formed. Sulfur doping can participate in the formation of the SEI film, generate a stable interface layer, reduce electrolyte decomposition and irreversible consumption of active lithium, and improve the initial coulombic efficiency. Nitrogen doping can construct an electron high-speed channel and improve conductivity. The conductive hollow carbon spheres are coated with MXene nanosheets and deposited on the surface of foamed carbon. Through the three-level synergy of layered, hollow, and foamed forms, a rigid-flexible effect can be achieved while alleviating volume expansion.

The invention discloses a method for synthesizing a platinum-based nitrogen-doped graphdiyne catalyst based on an atomic layer deposition technology and application of the platinum-based nitrogen-doped graphdiyne catalyst. Firstly, hexabromobenzene and calcium carbide are subjected to vacuum ball milling, calcination and purification to obtain a graphdiyne carrier, then the graphdiyne carrier and melamine are mixed and calcined to achieve nitrogen doping of the carrier, and then loading of platinum nanoparticles is accurately controlled through an atomic layer deposition technology. According to the method, the characteristics of an atomic layer deposition technology are utilized, deposition parameters and the number of cycles are controlled, uniform distribution and size control of Pt nano-particles on porous graphdiyne are achieved, and a nitrogen-doped graphdiyne carrier and the platinum nano-particles have a synergistic effect. The platinum-based nitrogen-doped graphdiyne catalyst prepared by the invention has the specific surface area of 734.8 m < 2 > g < 1 > and the average pore size of 8.68 nm, and shows excellent electrocatalytic activity and dynamic performance in reaction.

The invention provides a magnetically soft alloy-based wave-absorbing composite material as well as a preparation method and application thereof, and belongs to the technical field of electromagnetic wave absorbing materials. The wave-absorbing composite material provided by the invention comprises various magnetically soft alloy substrates prepared from elements such as iron, cobalt, nickel and the like and nitrogen-doped carbon coating the surfaces of the magnetically soft alloy substrates. The coercive force of the soft magnetic alloy is relatively low, so that the magnetic domain wall movement and magnetic moment rotation resistance in the material are reduced, the magnetic conductivity is relatively high, and the nitrogen-doped carbon with high dielectricity is combined to construct a magnetic-dielectric structure, so that the impedance matching between the composite material and the space is improved, and the efficient absorption of electromagnetic waves is promoted. The magnetically soft alloy-based wave-absorbing composite material has the characteristics of strong electromagnetic wave absorption performance and wide absorption frequency band, and is simple in preparation technology and easy for large-scale production.