51results about "Carbon fluorides" patented technology

The invention belongs to the technical field of new energy batteries, and particularly relates to a fluorine-doped graphdiyne material and a preparation method and application thereof. The preparation method of the fluorine-doped graphdiyne material comprises the following steps: in a solvent system, mixing graphdiyne and a solid fluorine source, and drying to obtain a composite precursor; under the protective atmosphere, the composite precursor is annealed, so that the fluorine source is decomposed to release hydrogen fluoride and fluorine free radicals, the hydrogen fluoride or the fluorine free radicals are combined with carbon sites on graphdiyne through nucleophilic substitution, C-F bonds are formed, and the fluorine-doped graphdiyne material is obtained; the mass ratio of graphdiyne to the solid fluorine source is 30: (1-4). The fluorine-doped graphdiyne has the advantages that the defects are increased, the disorder is reduced, and the lithium storage capacity of the graphdiyne is improved, so that the long-term cycle performance and the high-rate performance are improved.

The invention relates to the technical field of gas purification, in particular to a carbon tetrafluoride purification system and method, and the purification system comprises a precooling unit, a low-boiling tower and a high-boiling tower; packing layers in array distribution are arranged in the low-boiling tower and the high-boiling tower, a distribution disc is arranged between the packing layers, and telescopic mass transfer parts in array distribution are arranged on the distribution disc; a low-boiling condenser and a high-boiling condenser are arranged at the tops of the low-boiling tower and the high-boiling tower respectively, and refrigerants of the low-boiling tower and the high-boiling tower are introduced into the telescopic mass transfer part through an input pipe after condensation operation is completed and then are discharged through an output pipe; the flow meter is used for detecting the gas discharge amount and the liquid backflow amount of the rectifying tower, the backflow ratio change of the rectifying tower is calculated according to the gas discharge amount and the liquid backflow amount of the rectifying tower, and then the amount of refrigerants introduced into the telescopic mass transfer part can be adjusted and controlled by adjusting the operation power of the booster fan and the opening size of the adjusting valve; therefore, the top height of the telescopic mass transfer part is adjusted.

The invention discloses a preparation method and application of a Ni-NH2-MOF-coated HPP-COF composite material for adsorbing and separating perfluorocarbon gas / nitrogen, and belongs to the field of gas separation. The method comprises the following steps: 1, preparing HPP-COF powder; 2, preparing Ni-NH2-MOF (Metal Organic Framework) powder; and 3, compounding. According to the invention, Ni-NH2-MOF and HPP-COF are introduced into the field of gas adsorption, and a method for combining COF and MOF materials is creatively provided by utilizing the interaction of specific recognition of a perfluorinated compound and an amino group and a polymerization reinforcing structure on the surface of HPP-COF; a PFCs / N2 mixed gas separator meeting actual production requirements is prepared, the high adsorption capacity of MOF and the high stability of COF are combined, the problems that a traditional static porous material is poor in selectivity, stability and acid resistance are solved, specific adsorption of MOF to PFCs is enhanced, and selectivity is improved.

The invention belongs to the technical field of hydrogen storage materials, and particularly relates to a metal borohydride composite material, a preparation method thereof and a hydrogen storage material. The preparation method comprises the following steps: activating the carbon-based carrier by adopting an alkaline substance; performing gas-phase fluorination treatment on the activated carbon-based carrier; the carbon fluoride-based carrier is mixed with a metal source, a boron source and a solvent, a solvothermal reaction is driven by hydrogen, metal borohydride is synthesized in situ on the surface of the carbon fluoride-based carrier, metal atoms in the generated metal borohydride react with F atoms in the carbon fluoride-based carrier to form a metal-F bridging phase, and meanwhile, the metal borohydride generates metal vacancies. The metal affinity of fluorine in the carbon fluoride-based carrier is utilized to induce nucleation loading of the metal borohydride in the synthesis process of the metal borohydride, and meanwhile, an interface chemical reaction is carried out to generate vacancies and bridging phases. Vacancies weaken B-H bonds, the hydrogen absorption and desorption heat / dynamics of the material are improved, and the bridging phase improves the structural stability and hydrogen absorption and desorption cycle performance of the material.

The invention relates to a method and a device for separating and refining nitrogen trifluoride and carbon tetrafluoride. The crude nitrogen trifluoride gas enters an adsorber in an adsorption state, an adsorbent selectively adsorbs carbon tetrafluoride, and a high-purity nitrogen trifluoride product is obtained at an outlet; meanwhile, hot inert gas is utilized to purge the adsorber in a desorption state, outlet regenerated gas enters a compressor after being cooled, and the regenerated gas enters a membrane separation assembly after being compressed; carbon tetrafluoride is used as permeation gas to permeate through the separation membrane, and residual waste gas is discharged to an incinerator. Main equipment comprises an adsorber in an adsorption state, an adsorber in a desorption state, a regeneration gas heater, a regeneration gas cooler, a compressor, a membrane separation assembly and the like. According to the method, nitrogen trifluoride and carbon tetrafluoride are separated through temperature swing and pressure swing adsorption, carbon tetrafluoride is efficiently and selectively adsorbed through the adsorbent to obtain the high-purity nitrogen trifluoride product, carbon tetrafluoride is separated and recycled through the membrane separation assembly, and the method has the advantages of being high in product purity and yield, low in cost and simple in process.

The invention relates to a carbon fluoride material and a preparation method thereof, an electrode plate and a battery. The preparation method comprises the following steps: S1, carrying out carbonization treatment on a vulcanized polymer precursor in an inert atmosphere to obtain a heteroatom-doped hard carbon material; s2, placing the heteroatom-doped hard carbon material in a mixed atmosphere containing a protective gas and a fluorination reagent, and carrying out fluorination treatment at 300-600 DEG C to obtain a fluorinated material; the volume ratio of the fluorination reagent in the mixed atmosphere is below 40%. According to the invention, the carbon fluoride material with controllable doping, high fluorination degree and stable skeleton structure can be prepared, and as an active material of a positive plate of a lithium carbon fluoride battery, the carbon fluoride material can exert high specific capacity and improve the rate capability of the lithium carbon fluoride battery.

The invention belongs to the technical field of perfluorinated gas purification, and particularly relates to a perfluorinated gas purification method. The method comprises the following steps: by taking perfluorinated gas containing fluorine-containing impurity gas as a raw material, reacting in a fixed bed reactor under the action of a catalyst, washing with water and alkali, and separating and purifying to obtain purified perfluorinated gas; the catalyst is a metal oxide with a mesoporous structure; the preparation method of the catalyst comprises the following steps: dissolving a metal salt and a surfactant in water, adding ammonia water, continuously stirring until no precipitate is generated, washing, filtering, drying, roasting, granulating and forming to obtain the catalyst, the surface active agent is a cationic surface active agent and a nonionic surface active agent, and the molar ratio of the cationic surface active agent to the nonionic surface active agent is 1: (0.1-0.5); the metal salts are salts of Al, Mg and Sr. According to the method, various non-perfluorinated organic matters can be treated at the same time, high-purity perfluorinated gas is obtained, the reaction process is mild in condition, and the process is simple and easy to operate.

Provided are a carbon fluoride modification method, modified carbon fluoride and a lithium / carbon fluoride battery. The modification method comprises: mixing carbon fluoride with a composite solvent, subjecting same to a modification treatment, and then performing solid-liquid separation, so as to obtain modified carbon fluoride, wherein the composite solvent comprises water and an ether solvent. The composite solvent is used to modify carbon fluoride; and under the synergistic effect of water and the ether solvent, unstable components in a carbon fluoride material can be removed by means of reaction, thereby improving the chemical stability of the carbon fluoride material and reducing side reactions of carbon fluoride with an electrolyte solution, and therefore the storage stability of a lithium / carbon fluoride battery is improved. The modification method is simple and feasible, does not need the step of pre-charging, and is easy to implement and suitable for large-scale production.

The invention discloses a halide-doped carbon skeleton, a preparation method thereof and application of the halide-doped carbon skeleton in a negative-electrode-free lithium metal battery, and belongs to the technical field of secondary batteries. The preparation method of the halide-doped carbon skeleton comprises the following steps: placing a carbon skeleton in a halide solution, and standing to obtain the halide-doped carbon skeleton. According to the halide-doped carbon skeleton prepared by the invention, the growth of lithium dendrites can be effectively inhibited by utilizing the synergistic effect of the halide and the carbon skeleton, the problem of dead lithium is solved, the cycling stability and safety of the battery are improved, and a new solution is provided for the design of a high-performance current collector of a negative-electrode-free lithium metal battery.

The invention relates to methods for processing ammonium polyfluoride and producing nitrogen trifluoride (NF3). The technical result is the creation of a comprehensive, low-waste, explosion-proof technology for producing nitrogen trifluoride and, additionally, a group of inorganic fluorides: nitrogen trifluoride, carbon tetrafluoride, carbonyl fluoride, hydrogen fluoride and hydrofluoric acid. The proposed method envisages removing excess liquid ammonium polyfluoride from a reactor and sending it to be flaked or reacting it with oxygen, or with oxygen and carbon, or with oxygen and hydrogen-containing substances, or with oxygen and carbon and hydrogen-containing substances, or with fluorine, or with fluorine and hydrogen-containing substances, and recovering low-boiling substances by distillation and isolating hydrogen fluoride or hydrofluoric acid.

The invention discloses a catalyst for cracking hexafluoroethane in crude carbon tetrafluoride gas, a preparation method of the catalyst and a carbon tetrafluoride production device and method. The catalyst comprises a carrier, active metal and a structural aid. The carrier is gamma-Al2O3, the specific surface area is 180-250 m / g, and the particle size is 3-5 mm; the active metal is one or more of nickel, copper, iron, cobalt and the like, and the loading capacity is 15-20wt%; the structural additive is selected from one of magnesium, calcium or strontium, and the loading capacity is 0.5-2.5%. The catalyst is prepared by dipping the alkaline earth metal auxiliary agent, roasting, then introducing active metal, aging, drying, reducing and carrying out fluorination activation, and is applied to deep cracking of CF4 crude gas. The purity of the cracking gas is more than 99% after the cracking gas is subjected to water washing, alkali washing and drying. The catalyst has the advantages of high activity, long service life and the like.

The invention discloses a vertical graphene skeleton confinement silicon fluoride-based composite material as well as a preparation method and application thereof, and belongs to the field of inorganic materials. Putting Si into a tubular furnace, and heating to 1000-1200 DEG C at the speed of 10 DEG C / min in an argon environment; converting the atmosphere into a hydrogen / methane mixture for reaction to generate Si (at) G; then mixing and grinding the Si (at) G and tetrafluoroterephthalic acid, transferring the mixture to a tubular furnace, and finally performing heat treatment in an argon atmosphere to obtain a Si (at) G-F composite material; the composite material is of a core-shell type compact structure, and the surfaces of silicon particles are coated with vertically growing graphene sheets (VGs) in a self-adaptive mode to form a tightly-crosslinked three-dimensional network; dispersed sphere-like particles are formed, and the surfaces of the particles are tightly coated with the corrugated graphene sheet layers; the vertical graphene framework confinement silicon fluoride-based composite material Si (at) G-F composite material disclosed by the invention shows excellent electrochemical performance, and a feasible new way is provided for the development of high-energy-density lithium ion batteries.

The present invention discloses a method and apparatus for synthesizing CF4 by activating SF6 using a two-stage dielectric barrier discharge (DBD) plasma. The present invention proposes a two-stage DBD plasma activation method for degrading SF6 and introducing CO2 gas to synthesize CF4. The first-stage DBD plasma reactor degrades SF6 molecules, breaking them down into fluorine atoms and other low-fluorine and sulfur small molecules. This step not only effectively degrades SF6 but also provides the necessary fluorine source for subsequent CF4 synthesis. The second-stage DBD plasma reactor uses CO2 as a carbon source to react with the low-fluorine and sulfur small molecules produced in the first reaction to generate CF4 gas. The CF4-containing mixed gas undergoes a first-stage condensation process to condense some of the fluorine-containing acidic waste gas into a liquid state. The remaining mixed gas then undergoes a second-stage condensation process to condense the CF4 gas into a liquid state and collect it, achieving efficient product separation and purification. Some acidic gases that do not participate in the reaction are treated in an alkaline absorption tank to reduce environmental harm.

The present invention discloses a method for preparing a silicon-carbon composite material by plasma modification, the silicon-carbon composite material and its applications. It includes at least the following steps: Step S10) putting aminated porous carbon into a deposition chamber, passing silane gas through the deposition chamber to deposit nanosilicon on the aminated porous carbon to obtain a silicon-carbon precursor material; Step S20) transferring the silicon-carbon precursor material to a chamber for plasma modification, passing a halogen gas in the form of plasma, and depositing the generated halogen ions on the surface of the silicon-carbon precursor material to obtain a silicon-carbon precursor material coated with halogenated carbon; Step S30) stopping the passage of the halogen gas and passing a carbon source gas in the form of plasma. The prepared silicon-carbon composite material forms a structurally stable core-shell structure, greatly reduces the expansion problem of silicon, and can significantly improve the cycle performance of a battery applied therewith. In addition, the process of this application is simple, and by using the plasma method to modify the silicon-carbon material, it is easy to achieve mass preparation and large-scale industrialization.

The invention provides hard carbon secondary particles and a preparation method thereof, a negative electrode plate and a sodium battery. The hard carbon secondary particle is formed by aggregating a plurality of hard carbon primary particles, and the median particle diameter D50 of the hard carbon primary particles is larger than or equal to 200 nm and smaller than or equal to 500 nm.

The present application relates to a kind of chemical separation system and method, specifically to a kind of system and method for realizing Kr / CF4 separation using rectification-membrane separation coupling.The present application uses molecular sieve membrane as the key separation membrane material, and designs a whole set of Kr / CF4 separation and purification process, which solves the problems of Kr / CF4 purification and large amount of heat consumption.

Provided is a method for producing tetrafluoromethane through plasma pyrolysis of waste polytetrafluoroethylene (PTFE). The method includes: subjecting the waste PTFE to a plasma pyrolysis reaction to obtain a pyrolysis product, and subjecting the pyrolysis product to quenching and gas-solid separation in sequence to obtain a pyrolysis gas including the tetrafluoromethane, wherein the plasma pyrolysis reaction is performed at a temperature of 1,800 K to 5,000 K.

The invention relates to a preparation method of a high-power pulse type composite positive electrode material and a battery, and the core of the composite positive electrode material is as follows: activating a carbon fluoride nanotube, introducing the carbon fluoride nanotube into a silver salt solution, sequentially adding a reducing agent for gradient chemical plating, and finally loading nano-silver particles on the surface of the carbon fluoride nanotube to obtain the high-power pulse type composite positive electrode material. Meanwhile, the reductive defluorination effect is triggered in the growth process of the nano-silver, the carbon defect configuration in the fluorinated carbon nanotube is optimized, and the wettability of the material to an electrolyte is improved; the construction of an in-situ high-conductivity silver-carbon three-dimensional network and the reconstruction of an intrinsic structure are realized in one step, and the obtained composite material can meet the extreme requirements of ultrahigh-power pulse discharge on instantaneous electron conduction, rapid ion migration and low impedance at the same time. Severe polarization and impedance surge under large pulse current can be fundamentally inhibited, and the ultrahigh-rate pulse discharge capability which cannot be achieved by a traditional lithium / carbon fluoride battery is realized.

Provided are a carbon fluoride modification method, modified carbon fluoride and a lithium / carbon fluoride battery. The modification method comprises: mixing carbon fluoride with a composite solvent, subjecting same to a modification treatment, and then performing solid-liquid separation, so as to obtain modified carbon fluoride, wherein the composite solvent comprises water and an ether solvent. The composite solvent is used to modify carbon fluoride; and under the synergistic effect of water and the ether solvent, unstable components in a carbon fluoride material can be removed by means of reaction, thereby improving the chemical stability of the carbon fluoride material and reducing side reactions of carbon fluoride with an electrolyte solution, and therefore the storage stability of a lithium / carbon fluoride battery is improved. The modification method is simple and feasible, does not need the step of pre-charging, and is easy to implement and suitable for large-scale production.

The invention discloses a fluorocarbon-doped modified lithium ion battery ternary positive electrode material, a preparation method thereof and a battery. The preparation method comprises the following steps: mixing Ni < 0.838 > Co < 0.114 > Mn < 0.048 > (OH) < 2 > and LiOH.H2O, grinding, and sintering to obtain a high-nickel positive electrode material NCM; the preparation method comprises the following steps: grinding and mixing a high-nickel positive electrode material and polyvinylidene fluoride, dissolving in absolute ethyl alcohol, heating in a water bath, and stirring to obtain a gelatinous material; and drying the gel material in vacuum, grinding to obtain solid powder, and sintering for the second time in an inert gas atmosphere to obtain the fluorine-carbon doped modified lithium ion battery ternary positive electrode material. The fluorine-carbon-doped modified ternary positive electrode material is prepared by adopting a doping and coating dual-modification method and utilizing a high-temperature solid-phase method, and a TM-F bond with higher bond energy can be formed by F doping under high cut-off voltage, so that the fluorine-carbon-doped modified ternary positive electrode material has the advantages of improving the cycle performance and the rate capability of an NCM material, and improving the structural stability and the electrochemical performance of the high-nickel positive electrode material.

The application discloses a kind of sulfur selenium co-doped carbon fluoride materials, preparation method and application thereof, belong to carbon fluoride material field, a kind of sulfur selenium co-doped carbon fluoride material, including carbon fluoride, carbon fluoride surface doped with sulfur selenium compound, the mass fraction of sulfur selenium compound is 9.99%-30%.The sulfur selenium co-doped carbon fluoride material of the application, preparation method and application thereof synthesize a kind of sulfur selenium co-doped carbon fluoride material by simple heating treatment, can improve the discharge voltage and rate capability of carbon fluoride material under large rate.

The application discloses carbon fluoride directly using calcium fluoride as raw material and a preparation method and application thereof. The method mainly comprises the following steps: mixing a certain mass of calcium fluoride and hydrogen phosphate of alkali metal for 1h-48h, then adding a certain mass of carbon powder and continuing to mix for 1h-48h; placing the mixture into a fixed bed reactor, vacuumizing to 0.005-0.1kPa, and then introducing inert gas, and keeping the pressure of the reaction system to be 10kPa-95kPa; after heating to 200-1000 DEG C, the reaction is carried out for 2-48h, and then the reaction is stopped; the obtained product is soaked in sulfuric acid, cleaned with deionized water until neutral, and dried to obtain carbon fluoride material. The method directly uses calcium fluoride for fluorination, does not use hydrogen fluoride and fluorine source using hydrogen fluoride as an intermediate product for fluorination, can reduce energy demand, simplify the process, improve safety, and greatly reduce the production cost of carbon fluoride.

The present invention belongs to the field of battery technology and provides a method for modifying carbon fluoride, modified carbon fluoride, and a lithium / carbon fluoride battery. The modification method comprises mixing a carbon fluoride material, an acid anhydride, and a solvent, and performing a modification treatment to obtain the modified carbon fluoride. The present invention improves the stability of the carbon fluoride material itself by using an acid anhydride and a solvent to form a solution system containing an acid anhydride compound to modify the carbon fluoride material. This effectively removes free fluorine and active carbon-fluorine bonds in the carbon fluoride material, thereby improving the stability of the carbon fluoride material, resolving the problem of side reactions between the carbon fluoride and the electrolyte, and further improving the storage stability of the carbon fluoride battery.

The invention discloses a preparation method of a carbon fluoride positive electrode material based on an agar-based hierarchical pore structure, and belongs to the technical field of preparation of positive electrode materials. According to the method, biomass agar is used as a three-dimensional network skeleton raw material, potassium citrate is used as an activating agent, and the method is realized through three key steps of composite hydrogel preparation, graded pore biomass charcoal preparation and fluorination reaction. The preparation method specifically comprises the following steps: dissolving agar and 1-3g of potassium citrate at 95 DEG C to form composite hydrogel, carbonizing at 800 DEG C to obtain graded pore biomass charcoal, introducing fluorine / nitrogen mixed gas with the volume ratio of 3: 7, and carrying out fluoridation reaction at 200 DEG C for 4 hours to obtain a target material. By utilizing the gelation characteristic of agar at a high temperature, the composite gel with a three-dimensional network structure is firstly constructed, and the carbon precursor with a hierarchical pore structure is prepared after the carbonization treatment process, so that the discharge voltage of the carbon fluoride positive electrode is improved on one hand, and the volume expansion and heat release conditions of the positive electrode are reduced on the other hand.

The invention discloses a carbon fluoride dot photocatalyst, a preparation method thereof and application of the carbon fluoride dot photocatalyst in photocatalytic preparation of hydrogen peroxide. The carbon fluoride dot photocatalyst is synthesized by reacting tetrafluoroterephthalic acid and terephthalic acid or tetrafluoroterephthalic acid and p-phenylenediamine through a hydrothermal method, and has a graphene-like layered structure; c-F covalent bonds are formed in a carbon skeleton; the preparation method comprises the following steps: adding tetrafluoroterephthalic acid and terephthalic acid or tetrafluoroterephthalic acid and p-phenylenediamine into water, uniformly mixing, carrying out hydrothermal reaction, and filtering, purifying and drying a reaction product to obtain solid fluorinated carbon dot powder. According to the fluorinated carbon dot photocatalyst disclosed by the invention, through fluorination, the fluorinated carbon dot material has a wider light absorption range, more efficient carrier separation capability and more hydrophobic physical characteristics, so that the reaction efficiency of photocatalytic H2O2 production is improved.

This invention provides a method for producing carbon tetrafluoride using fluoroform as a raw material, and a pyrolysis and purification apparatus, which relate to the technical field of fluoroform resource utilization. Fluoroform is injected into a thermal plasma reactor and subjected to a pyrolysis reaction at 1500-5000 K to obtain carbon tetrafluoride. Compared to conventional tubular furnace pyrolysis or high-temperature muffle furnace pyrolysis, the thermal plasma reactor used in this invention relies on the synergistic effect of highly active electrons and heavy particles at high temperatures, resulting in significant electron excitation. This allows for efficient cleavage and directional reorganization of chemical bonds in fluoroform molecules without the use of catalysts or fluorine gas, resulting in high fluoroform conversion, high carbon tetrafluoride selectivity, and low energy consumption. Furthermore, the method provided by this invention has a short reaction time, large throughput, is safe and controllable, and the pyrolysis reaction products have a simple composition and are easy to separate and purify. It also consumes low cost and energy, making it suitable for industrial continuous scale-up production.

The application discloses a fluorinated carbon material and a preparation method and application thereof, and the method comprises the following steps: (1) putting a carbide into a fixed bed reactor, and vacuumizing to 0.005-0.1 kPa; the carbide is SiC; (2) after heating to 200-600 DEG C, inert gas is introduced, the pressure of the reaction system is kept to 10 kPa-95 kPa, then inert gas containing fluorinated reagent is continuously introduced, and reaction is carried out at 200-600 DEG C for 4-96 hours; the fluorinated reagent is a mixed gas of hydrogen fluoride and gas phase fluorinated substance; (3) the product obtained in the step (2) is soaked with an alkali solution, cleaned with deionized water until neutral, and dried to obtain the fluorinated carbon material. The preparation method can make the uniform distribution of fluorocarbon bonds in the fluorinated carbon material, and further improve the specific capacity of the fluorinated carbon material.

The invention discloses a high-energy-density carbon fluoride-sulfur-carbon composite positive electrode material and a preparation method thereof in the field of battery material preparation, the composite positive electrode material is mainly formed by compounding a carbon fluoride material and nano sulfur particles through a hydrothermal reaction, and the nano sulfur particles are uniformly distributed on the surface and between layers of carbon fluoride. In the carbon fluoride-sulfur-carbon composite positive electrode material, the open-circuit voltage of carbon fluoride is slightly higher than that of a sulfur-carbon material, the carbon fluoride material starts to discharge at the initial discharge stage of the composite material, and carbon fluoride discharge products mainly comprise lithium fluoride and conductive carbon and can provide a conductive agent effect for sulfur particles, so that the problem of low sulfur conductivity can be solved without adding the conductive agent. As an active substance, nano sulfur provides a large amount of capacity in the middle and later periods of discharge, so that the problem of material activity failure caused by lithium fluoride is solved, and the voltage platform and capacity in the later period of discharge are improved; and the actual energy density of the carbon fluoride-sulfur carbon composite positive electrode material is integrally improved.

The invention relates to the use of a carbon-based fiber sheet for improving the overvoltage of a lithium-sulfur battery. The lithium-sulfur battery includes: a positive electrode; a negative electrode; a separator interposed between the positive electrode and the negative electrode; and an electrolyte impregnated therein, in which the carbon-based fiber sheet is interposed between the positive electrode and the separator, in which the specific surface area of the carbon-based fiber sheet is 5 m2 / g to 500 m2 / g, nitrogen is doped in the carbon-based fiber sheet at a doping concentration of 10 wt% to 25 wt%, and the thickness of the carbon-based fiber sheet is 0.1 [mu] m to 100 [mu] m. The carbon-based fiber sheet for a lithium-sulfur battery according to the present invention is doped with a high concentration of nitrogen, thereby achieving an effect of preventing diffusion by adsorbing lithium polysulfide eluted from a positive electrode during charging and discharging, thereby suppressing a shuttle reaction, and thus improving the capacity, lifespan characteristics, and overvoltage of a lithium-sulfur battery.

This invention proposes a three-dimensional Li-type nanodiamond with fluorinated carbon as the substrate and nanodiamond as the binding site. 1.5 Na 1.5 V2(PO4)3 / NDs / CF x This invention relates to a cathode material and its preparation method, belonging to the technical field of cathode materials for lithium-ion batteries. The cathode material obtained by this invention exhibits good cycle stability when applied to the cathode of a lithium-ion battery. At 50 mA g... ‑1 The specific capacitance after 200 cycles at current density is 162 mA hg ‑1 ; at 1000mA g ‑1 At high current densities, it still achieves a significant 96 mA hg after 1000 cycles. ‑1 It exhibits long-term cycling stability and high capacity performance. The preparation method used in this invention has the advantages of simple process, easy implementation, and easy scale-up, and is expected to be mass-produced in the future.