41results about How to "Increase layer spacing" patented technology

This invention belongs to the field of hard carbon technology, specifically relating to a bamboo-based and lignin-based hard carbon composite material, its preparation method, and its applications. The process involves pretreating raw materials to obtain pretreated material; pretreating the pretreated material with an acidic oxidant to obtain acidic oxidant pretreated material; pre-oxidizing the acidic oxidant pretreated material to obtain pre-oxidized material; pre-carbonizing the pre-oxidized material under a protective atmosphere to obtain pre-carbonized material; pulverizing the pre-carbonized material to obtain pulverized material; acid washing followed by water washing to obtain purified material; soaking the purified material in acid, filtering, and drying to obtain soaked material; mixing the soaked material with a modifier, and high-temperature coating and carbonizing under a protective atmosphere to obtain bamboo-based coated hard carbon or lignin-based coated hard carbon. Mixing the two types of hard carbon and carbon coating yields a bamboo-based and lignin-based hard carbon composite material, which is used in negative electrode sheets and batteries. When applied to batteries, the hard carbon composite material of this invention can improve battery energy density.

This invention provides a hard carbon material, its preparation method, and its application. The preparation method includes the following steps: heating, mixing, and granulating a precursor, dopant, molten salt agent, and curing agent to obtain mixed particles; and carbonizing the mixed particles to obtain the hard carbon material. The preparation method of this invention, through the synergistic effect of heteroatom doping and molten salt etching, combined with mixed granulation, ensures the effectiveness of doping and etching, increases the interlayer spacing of the hard carbon material, introduces additional graphite microcrystal defects and active centers, and increases defects on the surface and edges of the carbon layer, thereby improving the cycle and rate performance of sodium-ion batteries.

The invention relates to amino acid modified red-mud-based magnesium-iron-aluminum hydrotalcite and a preparation method and application thereof.The preparation method comprises the following steps that red mud and inorganic acid are mixed and heated and leached under the stirring condition, an obtained leaching product is subjected to solid-liquid separation, and upper-layer acid leaching liquid containing iron and aluminum and residues are obtained; mixing the obtained upper-layer acid leaching solution with amino acid to obtain a mixed solution; adding magnesium salt into the obtained mixed solution, and carrying out coprecipitation reaction to obtain turbid liquid; and centrifuging, washing and drying the obtained turbid liquid to obtain the amino acid modified red mud-based magnesium-iron-aluminum hydrotalcite. Iron and aluminum elements in the red mud are directly extracted, the cost is reduced, and meanwhile the performance and the additional value of the hydrotalcite product prepared from the red mud are remarkably improved; amino acid molecules are introduced, the crystallinity, the specific surface area and the adsorption capacity of the magnesium-iron-aluminum hydrotalcite are improved, a co-precipitation reaction is adopted, the reaction temperature is low, the reaction time is short, and the prepared amino acid modified red-mud-based magnesium-iron-aluminum hydrotalcite can be used for treating phosphorus-containing wastewater.

The application belongs to the technical field of fertilizers, and particularly relates to a humic acid organic-inorganic compound fertilizer with slow release and improved fertilizer utilization rate and a preparation method thereof. The humic acid organic-inorganic compound fertilizer comprises the following raw materials in parts by weight: 22-30 parts of biogas residue, 35-55 parts of humic acid, 8-13 parts of fine columnar algae powder, 5-8 parts of urea, 12-17 parts of ammonium sulfate, 12-15 parts of superphosphoric acid calcium, 15-20 parts of potassium sulfate and 10-15 parts of slow release coating suspension. Test results show that the humic acid organic-inorganic compound fertilizer with slow release and improved fertilizer utilization rate prepared by the application can reduce the nitrogen and phosphorus release rates of the humic acid inorganic compound fertilizer, has better slow release effect, significantly promotes the plant height, stem diameter and root length of soybeans and corn, has obvious growth promotion effect, and has wide application prospect.

This application relates to the field of energy storage materials technology, and more particularly to a titanium-based active material, its preparation method, and its application. The titanium-based active material comprises a mixed oxide having a layered perovskite structure, the mixed oxide having the general chemical formula shown in Formula 1, M... 2± a La x‑y M1 y B n‑z M2 Z O (3n+1)‑δ Q δ Formula 1; in Formula 1, the M site includes H and / or an alkali metal element; the M1 site includes at least one of Mg, Ca, Sr, Ba, and rare earth elements; the M2 site includes a specified transition element and at least one of Al, Ga, In, Si, Sn, Sb, and Bi; the Q site includes at least one of F, Cl, Br, I, N, and S; the B site satisfies: Nb 2n‑3x‑z Ti 3x‑n Or Nb 2n‑3x Ti 3x‑n‑z This titanium-based active material possesses high energy density, ultra-fast charging capability, long cycle life, and intrinsic safety.

The invention provides graphene, a preparation method thereof and graphene slurry. The preparation method of the graphene comprises the following steps: obtaining graphite; carrying out acid treatment on the graphite to disperse the graphite in concentrated sulfuric acid to obtain a graphite dispersion liquid; carrying out oxidation treatment on graphite to enable the graphite dispersion liquid to be sequentially mixed with potassium permanganate and hydrogen peroxide for reaction, and carrying out suction filtration to obtain graphene oxide; carrying out solvation treatment on the graphene oxide, and adding the graphene oxide into a strong-polarity aprotic solvent to carry out purification modification, so as to obtain pretreated graphene oxide; and carrying out reduction operation on the pretreated graphene oxide. According to the preparation method of the graphene, the preparation of the graphene with relatively high conductivity and relatively good dispersion stability can be realized.

The application belongs to the field of nanomaterials and electrocatalysis, and specifically designs a single-atom electrocatalyst, which is formed by carbonizing a precursor mixed with nitrogen-containing organic matter and transition metal salt in a way parallel to single-atom generation. The nitrogen-doped carbon nanosheet prepared from the metal salt has the characteristics of rich pore structure, large specific surface area and high graphitization degree, and can capture single-atom metal to form a single-atom catalyst. In the preparation process, the transition metal salt acts as a template, a metal source and a pore-forming agent, and has a catalytic effect on the formed carbon material, thereby improving the graphitization degree of the carbon material. The single-atom catalyst prepared by the application has a high specific surface area and a developed pore size structure, which improves the exposure rate of active sites, and the carbon with a high graphitization degree not only improves the conductivity but also improves the corrosion resistance of the catalyst in an alkaline environment, thereby improving the stability of the catalyst.

This invention relates to the field of zinc-ion battery technology, and more particularly to a zinc-ion battery using vanadium pentoxide as the positive electrode material and its activation method. The activation method for a zinc-ion battery using vanadium pentoxide as the positive electrode material involves charging and discharging the battery at a temperature of 50-70°C. This invention performs a long-cycle rapid activation process in an oven at 50-70°C, altering the interlayer structure of vanadium pentoxide, thus expanding the interlayer spacing. This allows the vanadium pentoxide to exhibit an initial discharge specific capacity of 335 mAh / g in just two cycles at a current density of 0.2 A / g. This invention has advantages such as short reaction time, rapid capacity increase, and stable performance. When applied to the preparation of positive electrode materials for aqueous zinc-ion batteries, it can significantly improve production efficiency and material performance.

The invention relates to the technical field of magnesium phosphate cement materials, and particularly discloses a magnesium potassium phosphate cement-based material with high compactness and high salt corrosion resistance and application of the magnesium potassium phosphate cement-based material. The magnesium potassium phosphate cement-based material is prepared from the following components in parts by weight: 30 to 40 parts of dead burned magnesium oxide, 15 to 20 parts of monopotassium phosphate, 3 to 5 parts of retarder, 0.01 to 0.03 part of crystalline phosphate, 30 to 40 parts of fine aggregate and 8 to 13 parts of mixing water. Wherein the molecular formula of the crystalline phosphate is KNaMg2 (PO4) 2.14 H2O. By introducing the crystalline phosphate in a special structural form, the hydration evolution path and the microstructure of the magnesium potassium phosphate cement-based material in a salt erosion environment are effectively improved, and the salt erosion resistance is remarkably improved.

The invention discloses a preparation method and application of a bentonite-based adsorption material for sewage treatment, and belongs to the technical field of bentonite adsorption materials. The preparation method comprises the following steps: adding tannic acid and quercetin into deionized water, and uniformly stirring to obtain a composite solution; and uniformly mixing the modified bentonite and the modified activated carbon, adding the mixture into the composite solution, performing ultrasonic treatment, standing at room temperature, and performing suction filtration, washing, drying and grinding to obtain the bentonite-based adsorption material for sewage treatment. The bentonite is firstly modified, more active sites are introduced, the interlayer spacing is enlarged, and the specific surface area, the dispersity and the stability are improved, so that the adsorption performance of the bentonite is effectively improved. Then the modified bentonite and the modified activated carbon are mixed and then placed in a mixed solution of tannic acid and quercetin to be treated, and the adsorption performance of the material on heavy metal ions and organic pollutants is further enhanced.

The present application relates to the technical field of mineral material microcharacterization, and in particular to a method for dispersing clay mineral monolayer suitable for transmission electron microscope observation. The method for dispersing clay mineral monolayer based on stage alcohol intercalation and exfoliation comprises the following steps: dispersing clay mineral in deionized water to obtain a clay mineral suspension system by stirring; adding small molecule alcohol to the suspension system first and then adding macromolecular alcohol, and stirring to obtain a dilute dispersion system; performing ultrasonic treatment to make the clay mineral form a dispersion system mainly in monolayer or few-layer structure; dropping onto a carrier film for transmission electron microscope to make the lamella spread on the surface of the carrier film; and observing by using a transmission electron microscope. The present application is conducive to obtaining clay mineral monolayer samples with good dispersion and complete structure, and is suitable for morphology and structure characterization under transmission electron microscope.

The application relates to the technical field of batteries, in particular to a negative electrode material, a preparation method thereof and a battery. The negative electrode material comprises a substrate and a carbon coating layer coated on at least part of the surface of the substrate; wherein the substrate comprises hard carbon, the hard carbon is a biomass-based hard carbon material, and the hard carbon contains C elements and O elements, and the atomic ratio of O and C satisfies O:C=1:20-1:10. The preparation method of the negative electrode material comprises the following steps: soaking pretreated biomass material in a chloride solution, sintering to obtain a hard carbon precursor; mixing the hard carbon precursor with an acid solution, adding peroxodisulfate, and after mixing, separating and drying, obtaining a hard carbon material containing an epoxy group; performing carbon coating treatment on the hard carbon material containing the epoxy group to form a carbon coating layer on at least part of the surface of the hard carbon, and obtaining the negative electrode material. The application can improve the capacity and kinetic performance of the negative electrode material, and improve the capacity, initial efficiency and cycle performance of the battery.

The invention provides a lithium-rich manganese-based positive electrode material and a preparation method thereof, a positive plate and a battery. The lithium-rich manganese-based positive electrode material comprises a lithium-rich manganese-based core material and a coating layer coating the lithium-rich manganese-based core material, the alkali metal layer of the lithium-rich manganese-based core material at least comprises Mg element, and the coating layer comprises lithium fluoride. The lithium-rich manganese-based positive electrode material disclosed by the invention has high capacity, high structural stability and excellent interface durability, and can meet the performance requirements of a high-energy-density battery under complex working conditions.

The application provides a kind of sodium ion battery negative electrode material and its preparation method and application.The negative electrode material includes black phosphorus, carbon carrier and sodium salt;The morphology of the carbon carrier is the morphology of LDH template;The black phosphorus and sodium salt are compounded in the carbon carrier;The carbon carrier is also doped with double metal ions, and the double metal is the double metal element in the LDH template.The negative electrode material provided by the application has multiple bonding effects between the carbon carrier, phosphoric acid, double metal ions and sodium salt, which ensures the stability of the material interface and effectively inhibits the volume expansion of black phosphorus during the cycle process;And the interaction between each substance, synergistic effect, makes the negative electrode material have excellent cycle stability and high reversible capacity, and also has good rate performance.

The application discloses a sodium ion battery layered oxide positive electrode material based on a high ion potential doping element combination and a preparation method thereof. m N n O2, wherein m and n range from 0 to 1 and m+n=1, M is an element participating in charge compensation and is at least one of Ni, Fe, Mn and Co; Na is a base element; and N is an element not participating in charge compensation and is at least one of Mg, Ti, V, Cr B, Al, Ga, B and Ga. ‑1 The application selects more than one kind of doping high ion potential element to make the weighted ion potential of the doping element metal higher than a critical value 6 Å, so that the material has better sodium ion diffusion kinetics and rate performance.

This invention discloses a preparation method and application for improving the fast-charging performance of graphite composite materials. The preparation method involves mixing a graphite precursor with a catalyst and a conductive liquid, ball milling the mixture, followed by pre-carbonization, low-temperature graphitization, and acid washing to obtain a graphite precursor material. Then, the graphite precursor is mixed with a heteroatom polymer, a phosphorus compound, and an organotitanium compound, and heat-treated to obtain the graphite composite material. The graphite composite material prepared by this invention utilizes a catalyst to enhance the anisotropy of carbon during graphitization, and improves electronic conductivity through the conductive agent doped into the core. The titanium dioxide coating on the composite material's outer shell has the characteristics of large interlayer spacing, low expansion rate, and structural stability, which improves the lithium-ion insertion / extraction rate and rate performance. Since phosphorus itself has high specific capacity and a high voltage plateau, phosphorus doping improves the specific capacity and voltage plateau of the composite material, thus enhancing its fast-charging performance.

The application discloses a kind of core-shell structure fast charging long cycle artificial graphite, its preparation method, negative electrode material and purposes, including, petroleum coke or acicular coke aggregate D50 8~20 μm, non-biomass hard carbon raw material powder D50 1~10 μm and pitch are mixed according to the mass ratio hard carbon: pitch = 1:9~5:5, aggregate: composite coating agent = 95:5~85:15, pre-mixing S1 is carried out at 100~200 DEG C, 160~220 DEG C melt kneading granulation S2, carbonization S3 is carried out at 600~1000 DEG C, and graphitization S4 is carried out at 2800~3200 DEG C, and core-shell structure artificial graphite is prepared by one-step method.The shell layer is composed of uniformly dispersed graphitized hard carbon and soft carbon, and is densely coated outside the artificial graphite core.The first reversible specific capacity of the product is greater than or equal to 350 mAh / g, the first coulombic efficiency is greater than or equal to 93%, and the capacity retention rate at 5.0C / 0.2C is greater than or equal to 84%, with excellent fast charging performance and cycle stability, simple process and low cost.

The application relates to a high-strength glass fiber modified plastic and a preparation method thereof, and belongs to the technical field of high polymer composite materials. The glass fiber modified plastic comprises the following components in parts by weight: resin 40-90 parts, modified glass fiber 10-20 parts, lubricant 0.4-3 parts and antioxidant 0.5-2 parts; the modified glass fiber comprises a glass fiber matrix, a polydopamine layer coated on the surface of the glass fiber matrix and Sr-doped ZnS nanosheet layers formed on the surface of the polydopamine layer; by constructing a polydopamine / Sr-doped ZnS nanosheet composite interface layer on the surface of the glass fiber, the interface bonding force between the glass fiber and the plastic matrix is significantly improved, meanwhile, the composite material is endowed with excellent ultraviolet aging resistance, the obtained glass fiber modified plastic has high strength and high durability, and can be widely applied in the fields of automobile industry, aerospace, electronic appliances and the like.

The application discloses a preparation method of a regenerated in-situ doped positive electrode material, and comprises the following steps: (1) adding waste lithium ion battery positive electrode material into a mixed solution of 2-hydroxypropionic acid and quinic acid to perform a first reaction; (2) adding a solution of glucosamine and / or aminobutyric acid into the system after the first reaction to perform a second reaction, thereby obtaining a leaching solution rich in valuable metal ions; (3) adjusting the molar ratio of the valuable metal ions and M 2+ , adjusting the pH, and heating and evaporating and concentrating to form a gel; the ionic radius of M 2+ is 1.3-2.0 times the average ionic radius of Ni 2+ , Co 2+ , and Mn 2+ ; (4) performing step-by-step calcination on the gel to obtain a primary regenerated material doped in-situ; and (5) spraying and pyrolyzing the primary regenerated material in a surface treatment agent and then performing low-temperature heat treatment. The application further provides a regenerated in-situ doped positive electrode material.

The application discloses an organic matter intercalated vanadium pentoxide (V2O5) positive electrode composite material and a preparation method and application thereof, and belongs to the technical field of micro-nano materials and electrochemistry. The application uses V2O5 with a wide source as a raw material, and uses bis(4-nitrophenyl) phosphate, diphenyl phosphate, ethyl phosphate and triethyl phosphate as objects to be inserted into adjacent layers of the V2O5 to serve as a support. The application not only improves the interlayer spacing of the V2O5, overcomes the problem that zinc ions are difficult to be deintercalated in the interlayer of the V2O5 in a cycle process, but also improves the structural stability, and improves the capacity and cycle stability.

This application discloses a special graphite plate for fuel cells and its preparation process, relating to the field of fuel cell technology. The raw materials, by weight, include 78-82 parts pre-expanded graphite, 2-3 parts carbon black, 6-8 parts graphene-modified mesophase carbon microspheres, 1.5-2.5 parts silicon carbide whiskers, 4-6 parts borosilicate-modified phenolic resin, 0.3-0.5 parts silane coupling agent, and 20-30 parts anhydrous ethanol. The pre-expanded graphite, carbon black, graphene-modified mesophase carbon microspheres, and silicon carbide whiskers are added to a high-speed mixer for dry mixing. Then, borosilicate-modified phenolic resin and silane coupling agent are added, and high-speed shear mixing continues. Anhydrous ethanol is added, and after mixing, the materials are dried and crushed into powder. The obtained powder is placed in a mold and pressed into shape. The sample is then cured by stepped heating and pressing, and after cooling, the special graphite plate for fuel cells is obtained. The graphite plate provided by this application has excellent surface conductivity and mechanical strength.

This invention discloses a high-temperature resistant organic clay for drilling fluids, comprising the following components by weight: 50-80 parts sodium-based montmorillonite, 10-30 parts attapulgite, 10-30 parts long-chain quaternary ammonium salt, and 5-15 parts chelating agent. This invention uses a compound of montmorillonite and attapulgite as a modifying material to prevent the single layered structure of montmorillonite from discontinuing at high temperatures, thus affecting the high-temperature resistance of the organic clay. A long-chain quaternary ammonium salt is used as a primary intercalating agent to effectively penetrate the interlayers of montmorillonite, increasing the interlayer spacing. A chelating agent is then used as a secondary intercalating agent to connect adjacent montmorillonite layers using chemical bonds. Simultaneously, the primary intercalating agent and the montmorillonite are further connected to improve the problem of easy ionic bond desorption. This results in a high-temperature resistant organic clay for drilling fluids with a high temperature resistance exceeding 200℃, exhibiting a high colloidal content and good viscosity-enhancing and shear-lifting effects at this temperature.

This invention relates to the field of advanced petrochemical new materials technology, and discloses a luminescent composite material, its preparation method, and its application. The composite material comprises the following components: homopolymer polypropylene, polybutylene succinate, a compatibility modification system, double-modified rare-earth strontium aluminate luminescent powder, dispersant, antioxidant, weathering agent, toughening agent, nucleating agent, and silane coupling agent. This invention employs a compatibility modification system composed of maleic anhydride-grafted PP-g-PBS copolymer and double-modified nano-montmorillonite. The maleic anhydride-grafted PP-g-PBS copolymer constructs a chemical link between the polypropylene and polybutylene succinate molecular chains through a grafting reaction, reducing the interfacial tension between the two resins. The double-modified nano-montmorillonite, after ionic liquid intercalation and silane grafting treatment, exhibits increased interlayer spacing and improved surface activity, uniformly dispersed in the matrix, and acts as a physical crosslinking point, improving the compatibility of the matrix resin and preventing phase separation.

The invention belongs to the technical field of preparation of positive electrode materials, and particularly relates to a high-rate sodium vanadium phosphate positive electrode material, a preparation method thereof and a battery. The method comprises the following steps: S1, dissolving ammonium metavanadate and oxalic acid in water to form a solution A; s2, performing ultrasonic dispersion on CNT in absolute ethyl alcohol to obtain a dispersion B; s3, slowly dropwise adding the dispersion B into the solution A until a stable transparent blue solution C is formed; s4, sequentially introducing sodium dihydrogen phosphate and thioacetamide into the solution C, and stirring to form viscous gel; and S5, carrying out vacuum drying on the viscous gel to obtain a precursor, then carrying out high-temperature heat treatment on the precursor under the protection of a nitrogen atmosphere, and finally putting a product subjected to high-temperature heat treatment in a liquid nitrogen atmosphere for rapid cooling to obtain the high-rate sodium vanadium phosphate positive electrode material. The material has relatively low resistance and relatively large sodium ion diffusion coefficient, so that the reversible specific capacity is highest, and the rate capability is best.

This invention belongs to the field of inorganic nanoparticle preparation technology, and relates to a ball milling modification method for bifunctionalized thin-layer hexagonal boron nitride: Hexagonal boron nitride powder, guanidine hydrochloride, and urea are continuously heated and stirred to obtain a homogeneous mixture of a eutectic solvent formed by guanidine hydrochloride and urea and the hexagonal boron nitride powder; this mixture is poured into a ball mill jar containing grinding balls and a liner, and a certain amount of ethanol and water are added as dispersants for high-energy ball milling; after the material is separated from the grinding balls, the milled material is vacuum filtered, dried, and the resulting powder is dispersed in water, then ultrasonicated, allowed to stand, vacuum filtered, and dried to obtain bifunctionalized thin-layer hexagonal boron nitride. This invention not only has the advantages of readily available raw materials and simple process, but also high efficiency, environmental friendliness, and low energy consumption. The hexagonal boron nitride obtained by this method has thinner layers, good biocompatibility, low relative density, and good thermal conductivity.

The application discloses a preparation method of a biomass hard carbon negative electrode material, and comprises the following steps: (1) pre-carbonizing a biomass raw material, and then uniformly mixing the pre-carbonized biomass raw material with an alkali solution to obtain wet material; (2) high-temperature carbonizing the wet material in an inert atmosphere, and then rapidly cooling the high-temperature carbonized wet material to obtain carbonized biomass; the cooling rate is controlled to be 10-30 DEG C / min during the rapid cooling; and (3) physically stripping the crystalline substances on the surface of the carbonized biomass, and then crushing the carbonized biomass to obtain the biomass hard carbon negative electrode material. The biomass hard carbon needs high-temperature carbonization during processing, and the high-temperature carbonization process is used for impurity removal, so that the energy consumption is not additionally increased. The impurities are separated by using a physical method, and the process is simple and environment-friendly. Overall, the material prepared by the method has low impurity content, excellent sodium storage performance, low energy consumption in the preparation process, simple process and environment-friendly.

The invention relates to a high-capacity sodium-ion battery carbon negative electrode material and a preparation method and application thereof.The high-capacity sodium-ion battery carbon negative electrode material is prepared through the following steps that S1, petroleum coke is smashed to the target particle size, then mixed with hydrochloric acid and stirred at the constant temperature for t1, then a certain mass of a sodium tripolyphosphate aqueous solution x is added, constant-temperature stirring is continued for t2, filtering and washing are conducted, and precursor powder is obtained; and S2, mixing the precursor powder with a sodium tripolyphosphate aqueous solution y containing glucose, carrying out spray drying, mixing with high-softening-point asphalt, carrying out fusion granulation, carrying out gradient heating treatment in an inert atmosphere, and carrying out depolymerization and demagnetization on the obtained material to obtain the carbon negative electrode material. Compared with the prior art, the sodium ion battery carbon negative electrode material with high capacity and long cycle life is obtained.

This invention discloses a chloride-intercalated nickel-iron layered double hydroxide, its preparation method, and its application, belonging to the field of electrocatalytic materials technology. In this invention, chloride ions occupy the interlayer domains without disrupting the main layer structure, and the interlayer spacing is stably expanded through electrostatic interaction. The one-step hydrothermal method for preparing this material includes: immersing nickel foam in a mixed solution containing chloride salt, nickel salt, iron salt, and urea for a hydrothermal reaction, thereby obtaining an in-situ grown nanoflower-like array structure catalytic electrode. This catalytic electrode exhibits performance at 10 mA / cm² in alkaline water oxidation. ‑2 The overpotential is only 179 mV, allowing for stable operation for over 500 hours in anion exchange membrane water electrolysis devices. It also exhibits excellent electro-oxidation activity for biomass molecules such as glycerol, methanol, ethanol, and urea. This invention features a simple and low-cost preparation process, making it suitable for alkaline water electrolysis and biomass-assisted electrolysis hydrogen production.

This invention belongs to the field of new energy storage technology and discloses a method for preparing and applying anionic medium-entropy MXene electrode material. The chemical formula of the anionic medium-entropy MXene material is M. n+ 1X n T x The X site contains four anions: carbon, nitrogen, oxygen, and fluorine, forming a medium-entropy composition. The preparation method includes: mixing TiC, Ti, Al, TiN, Al2O3, and AlF3 in a specific molar ratio, and sintering at high temperature under an inert atmosphere to obtain the anionic medium-entropy MAX phase; then removing the Al layer by etching, followed by intercalation, ultrasonic exfoliation, and drying to obtain few-layer anionic medium-entropy MXene nanosheets. This invention achieves a medium-entropy effect by having multiple anions co-occupy the X site, and for the first time, by introducing highly electronegative fluorine (F) anions to co-occupy the X site with carbon, nitrogen, and oxygen, thus significantly regulating the interlayer dynamic hydrogen bond network and redox activity. In particular, the strong electron-withdrawing ability of F and its unique interaction with hydrogen bonds effectively suppress side reactions and stabilize the interlayer structure, resulting in high volumetric capacity, excellent rate performance, and long-term cycling stability.

The application discloses a kind of spherical sulfurized polyacrylonitrile-based hard carbon negative materials and preparation method and application thereof, and it is related to sodium ion negative material preparation technical field.The preparation method of the application includes: first, polyacrylonitrile and sulfur sublimate are added into ball mill jar in certain proportion and ball milled, then dried, finally placed in the tube furnace with inert atmosphere protection and carried out two-step heat treatment, finally obtain hard carbon negative material, the application also provides the application of the hard carbon negative material in the preparation of sodium ion battery.The application aims to prepare S-doped polyacrylonitrile-derived hard carbon material by sulfurizing treatment of polyacrylonitrile and sulfur sublimate, and then carbonizing at high temperature (>1200 DEG C).The preparation method provided by the application is simple, easy to operate, and the raw material carbon yield is high.The hard carbon negative electrode is prepared by ball milling and two-step heat preservation method, and has the advantages of high initial coulomb efficiency, good cycle performance and high rate performance.