46results about How to "Improve sodium storage performance" patented technology

The invention provides a preparation method of a multi-element doped asphalt-based hard carbon material for a negative electrode of a sodium-ion battery, which comprises the following steps: (S1) mixing and crushing asphalt and zinc salt of organic acid, and pre-oxidizing in an oxygen-containing atmosphere to obtain pre-oxidized asphalt particles; (S2) uniformly mixing the pre-oxidized asphalt particles, N-containing aromatic polyaldehyde and 1-hydroxyethylidene-1, 1-diphosphonic acid, and carrying out heating reaction in an inert atmosphere to obtain modified asphalt particles; and (S3) carrying out high-temperature carbonization on the modified asphalt particles in an inert atmosphere to obtain the multi-element doped asphalt-based hard carbon material. Firstly, an asphalt precursor and organic acid zinc are mixed and then pre-oxidized, then a cross-linking agent containing N and a cross-linking agent containing P are added for cross-linking, the obtained hard carbon material has a short-range ordered structure, and the sodium storage capacity and the sodium ion transmission capacity are both improved. The hard carbon material obtained by the preparation method has high specific capacity and first coulombic efficiency, and the rate capability is also improved.

The invention discloses low-impurity biomass hard carbon as well as a preparation method and application thereof. The low-impurity biomass hard carbon is prepared from biomass raw material powder through impurity removal and carbonization; the invention discloses a preparation method of low-impurity biomass hard carbon. The preparation method comprises the following steps: mixing biomass raw material powder with a strain of macro fungi, and culturing until the macro fungi grow sporocarp; the application of the low-impurity biomass hard carbon is that the low-impurity biomass hard carbon is used for preparing a sodium ion battery negative electrode material. According to the method provided by the invention, impurities such as inorganic salts and metal elements in the biomass raw material for preparing the biomass hard carbon can be effectively removed, and meanwhile, the microporous structure of the biomass hard carbon material is maintained, so that the sodium storage performance and the cycling stability of the biomass hard carbon material serving as a sodium-ion battery negative electrode material are improved.

The invention relates to the technical field of waste sodium-ion battery recovery, and discloses a water-based solution-based waste sodium-ion battery hard carbon material recovery and regeneration method and application of the water-based solution-based waste sodium-ion battery hard carbon material recovery and regeneration method. Comprising the following steps: disassembling and separating the waste sodium-ion battery to obtain a hard carbon negative pole piece; stripping the hard carbon active material from the surface of the current collector, and collecting hard carbon negative electrode powder in the waste battery; removing side reaction products on the surface of the hard carbon negative electrode powder by adopting a water-based solution treatment method, and carrying out solid-liquid separation, washing and drying to obtain a primary regenerated hard carbon material; according to the specific failure mechanism and failure degree of the hard carbon material in the battery, the primary regenerated hard carbon is further subjected to annealing treatment, and the high-performance value-added recycled hard carbon material is obtained. The method adopts a water-based solution recovery technology, and has the advantages of safety, environmental protection and low cost; and meanwhile, the recovery process is simple, convenient and feasible, and has higher economic benefits. The performance of the regenerated hard carbon material is remarkably recovered, and the regenerated hard carbon material can be reused for manufacturing the sodium-ion battery.

The invention discloses a multi-stage pickling and impurity removal method for a coal-based hard carbon precursor for sodium storage, comprising the following steps: pickling and impurity removal of coal-based material powder according to a mixed acid secondary pickling and impurity removal method or a single acid tertiary pickling and impurity removal method to obtain pickled coal-based material powder; sintering the pickled coal-based material powder at 500-800°C for 0-4h in an inert atmosphere, then carbonizing at 800-1450°C for 0.5-18h, and cooling to room temperature to obtain a coal-based sodium ion battery hard carbon material. The sodium ion battery prepared from the coal-based sodium ion battery hard carbon material has a first-cycle charge specific capacity of 270-300mAh / g, a first-cycle discharge specific capacity of 300-320mAh / g, a first-cycle coulomb efficiency greater than 90%, and trace metal elements and magnetic substances in the coal-based sodium ion battery hard carbon material meet the national standard for sodium ion battery hard carbon.

The invention discloses a soft carbon coated sulfur-nitrogen co-doped coal-based hard carbon material and a preparation method thereof.The preparation method comprises the steps that firstly, bituminous coal powder and thiourea particles are dissolved in absolute ethyl alcohol, fully stirred and mixed to be uniform, and after drying, bituminous coal-thiourea mixed powder is prepared; carrying out primary carbonization treatment on the bituminous coal-thiourea mixed powder in an inert atmosphere to prepare a sulfur-nitrogen co-doped coal-based hard carbon material; and depositing asphalt on the surface of the sulfur and nitrogen co-doped coal-based hard carbon material, and carrying out secondary carbonization treatment on the product to prepare the soft carbon coated sulfur and nitrogen co-doped coal-based hard carbon material, a sodium ion battery based on the soft carbon coated sulfur-nitrogen co-doped coal-based hard carbon material has high sodium storage specific capacity and first coulombic efficiency and high potential platform area sodium storage capacity proportion.

The invention relates to the technical field of sodium ion battery negative electrode material preparation, in particular to a melamine resin modified negative electrode material for a sodium ion battery. The material is prepared according to the following steps: mixing and grinding melamine resin and sulfur in an agate mortar; then putting the ground substance into a porcelain boat; putting the porcelain boat into a micro power-assisted tube furnace, and calcining in an argon environment; and after calcining, grinding the product into fine particles, and sieving to obtain the melamine resin modified negative electrode material for the sodium-ion battery. According to the invention, the melamine resin is used as a matrix to prepare the hard carbon material, and the melamine resin is used as a nitrogen source to prepare the hard carbon material with excellent cycle rate capability and high reversible specific capacity; the hard carbon precursor used in the past has fixed chemical components, and the sulfur is introduced to modify the resin, so that the storage of sodium is increased, and a new thought is provided for the negative electrode material of the sodium-ion battery.

The application relates to the technical field of battery materials, and discloses a sodium-philic carbon-based material, a negative-electrode-free current collector, a preparation method of the sodium-philic carbon-based material and a sodium metal battery. The preparation method of the sodium-philic carbon-based material comprises the following steps: providing a mixed solution, wherein the mixed solution comprises carbon source powder, an iron source and a solvent; fully reacting the mixed solution in a protective atmosphere at 160-240 DEG C; obtaining a carbon-loaded sodium-philic material after solid-liquid separation; fully calcining the carbon-loaded sodium-philic material in an inert atmosphere at 700-900 DEG C to obtain a porous sodium-philic precursor; and treating the porous sodium-philic precursor in a reaction gas atmosphere at 400-700 DEG C for 1-3 hours to obtain the sodium-philic carbon-based material. The reaction gas atmosphere is an ammonia gas and inert gas mixed atmosphere or an ammonia gas atmosphere. The material is coated on the surface of the negative-electrode-free sodium metal battery current collector, and can enhance the electrochemical performance of the battery.

The invention discloses a nitrogen-phosphorus-oxygen doped soft / hard carbon nanofiber composite material as well as a preparation method and application thereof. The nitrogen-phosphorus-oxygen doped soft / hard carbon nanofiber composite material is prepared from lignin, petroleum coke, polyacrylonitrile, phosphoric acid and other raw materials. Wherein the diameter of the nitrogen, phosphorus and oxygen doped soft / hard carbon nanofiber composite material is 140-230 nm; the mass fraction of carbon is 65.47%-77.86%, the mass fraction of nitrogen is 8.79%-13.24%, the mass fraction of phosphorus is 3.24%-6.11%, and the mass fraction of oxygen is 9.57%-15.43%; the BET specific surface area is 37.26 to 57.49 m < 2 > g <-1 >. The nitrogen-phosphorus-oxygen doped soft / hard carbon nanofiber composite material disclosed by the invention is applied to a sodium-ion battery negative electrode material, has the advantages of high specific capacity and long cycle life, and is wide in raw material source, simple to operate and convenient for large-scale production. The invention also discloses a preparation method and application of the nitrogen-phosphorus-oxygen doped soft / hard carbon nanofiber composite material.

The present invention relates to the technical field of sodium ion battery electrode materials, specifically a single-phase ternary iron-based sulfide selenide composite material and its preparation method and application, wherein the preparation method is to use sodium alginate with abundant reserves as a precursor; utilize the abundant carboxyl and hydroxyl groups in the structure to crosslink the chelation between iron ions in one step to form a gel of sodium alginate wrapped metal; after the gel is refrigerated, it is simultaneously sulfide-selenized with sulfur and selenium sources by vapor deposition in an inert atmosphere, and the corresponding single-phase ternary iron-based sulfide selenide composite material can be obtained after cooling to room temperature. The present invention has the characteristics of improving material structure and performance, improving the electrochemical properties of such negative electrode materials, including material conductivity, structural stability, specific capacity, cycle stability and rate performance of sodium ion batteries, and significantly improving the cycle performance and rate performance of sodium ion batteries.

The invention belongs to the technical field of hard carbon materials, and particularly relates to a preparation method and application of a polyurethane-based hard carbon material. The preparation method comprises the following steps: carrying out roasting carbonization and post-treatment on a solid polyurethane material at 900-1400 DEG C to obtain a powdery polyurethane-based hard carbon material; the solid polyurethane material is a polyurethane product prepared from reaction raw materials including isocyanate, non-phosphorus-containing polyol and phosphorus-containing polyol through a reaction. According to the invention, the polyurethane material is prepared by adding the phosphorus-containing polyol, and the polyurethane material is applied to the field of batteries as a negative electrode raw material, so that high carbonization yield can be maintained, and excellent performances such as initial coulombic efficiency, energy density, cycle capacity retention rate and the like of the battery can be realized.

The present invention belongs to the technical field of negative electrode materials, and specifically relates to a high-performance biomass-based hard carbon negative electrode material and a preparation method thereof, the preparation method comprising the following steps: pre-immersing the biomass raw material in an anhydrous ethanol / deionized water mixed solution, and obtaining clean biomass after washing and drying; then immersing in a diammonium hydrogen phosphate solution, and obtaining a biomass-based hard carbon precursor after drying, pre-oxidation cross-linking curing, pickling and other treatments; finally, obtaining a biomass-based hard carbon negative electrode material through high-temperature carbonization, purification, drying and other processes. The present invention uses diammonium hydrogen phosphate as a cross-linking curing agent and a heteroatom N and P element doping source, and obtains a biomass-based hard carbon negative electrode material through a pre-oxidation cross-linking curing reaction combined with a high-temperature carbonization process, providing a way and method for the preparation of high-capacity biomass-based hard carbon negative electrode materials, and effectively solving the problems of low loading of traditional hard carbon active substances and low stacking density.

The application relates to a sodium titanate nanofiber / reduced graphene oxide composite electrode material and a preparation method and application thereof. The composite electrode material has a two-dimensional sheet structure, the particle size is 1-6 mu m, the thickness is 10-20 nm, is composed of a few-layer reduced graphene oxide and sodium titanate nanofibers with a diameter of 5-10 nm loaded on the reduced graphene oxide, and is prepared by taking the few-layer reduced graphene oxide as a template, uniformly loading titanium dioxide particles, and then carrying out hydrothermal treatment in an alkali solution. Compared with the prior art, the synthesis method is simple in process, easy to scale up, and high in controllability. As a negative electrode of a sodium ion battery or a positive electrode of a sodium battery, the sodium titanate nanofiber / reduced graphene oxide composite electrode material has the advantages of high initial coulomb efficiency, low working voltage, high capacity, excellent rate characteristics and cycle stability, and has a broad market application prospect.

The invention provides a sodium ferric sulfate positive electrode material and a preparation method thereof, a sodium ion battery and electric equipment, and relates to the technical field of new energy. The preparation method of the sodium ferric sulfate positive electrode material comprises the following steps: mixing ferrous sulfate, sodium sulfate, boron nitride and a carbon material through ball milling to obtain a mixture; and sintering the mixture in an inert atmosphere to obtain the sodium ferric sulfate positive electrode material. The preparation method disclosed by the invention is simple in process and convenient for expanded production, and the synthesized sodium ferric sulfate has relatively high conductivity, relatively good sodium storage performance and relatively good rate capability. According to the sodium ion battery and the electric equipment, due to the fact that the sodium ferric sulfate positive electrode material prepared through the method is adopted, the first charge capacity can reach 102.27 mAh / g, the first discharge capacity can reach 100.03 mAh / g, the capacity retention rate can reach 96.24% after 1000 cycles under the 5C multiplying power, and the capacity retention rate can reach 81.41% under the 20C multiplying power.

The present invention relates to the field of sodium ion battery electrode materials, specifically a selenium-induced defect copper-based sulfur / selenide material and its preparation method and application, and a novel copper-based metal organic framework compound Cys-Cu precursor is preferentially prepared by a coprecipitation strategy; the precursor and a selenium source are then pyrolyzed and selenized under an inert atmosphere, and then naturally cooled to room temperature to obtain a product. The preparation method makes full use of the advantages of heteroatoms such as S / N in the ligand in the precursor, and a copper-based sulfur-selenide composite material with rich vacancies is obtained only by the preparation and selenization of the precursor, and the manufacturing process is simple and efficient, the cycle is short, and the stability is good. The composite material obtained by the method contains rich cation vacancies and a heterogeneous interface spontaneously constructed by copper-based sulfide and selenide, which can not only improve the material conductivity, promote effective electron / ion transport, but also create more sodium storage active sites, and further improve the material sodium storage capacity and structural stability.

The invention relates to a composite diaphragm, a preparation method thereof and a battery, and belongs to the technical field of battery materials, the composite diaphragm comprises a base membrane and a coating distributed on the surface of the base membrane; the coating comprises sodium super-ionic conductor type phosphate, a single-arm carbon nano tube and a binding agent, the mass ratio of the sodium super-ion conductor type phosphate to the single-arm carbon nanotube is (20-80): 1. The composite diaphragm provided by the invention has excellent heat shrinkage resistance, electrolyte infiltration performance and liquid absorption capability, and relatively high ionic conductivity and puncture strength, and the battery comprising the composite diaphragm has relatively high capacity and excellent cycle performance.

The present invention discloses a sodium ion battery positive electrode material precursor and a preparation method and application thereof. The sodium ion battery positive electrode material precursor includes a positive electrode material precursor and a NASICON type material precursor; the NASICON type material precursor is a substance that is converted into a NASICON type material after calcination. The present invention uses the NASICON type material precursor and the positive electrode material precursor in combination to effectively improve the sodium ion migration efficiency and sodium storage performance. Preferably, the NASICON type material is coated on the surface of the positive electrode material to improve the uniformity of the coating layer, thereby greatly improving the cycle performance and rate performance of the material. At the same time, the present invention solves the disadvantages of poor air and water stability of the coating in the sintering stage of the rear-end positive electrode material by using an ordinary positive electrode material precursor and a NASICON type material precursor in combination at the precursor end, reduces the complexity of the subsequent process, and reduces the production cost.

The invention provides a coconut shell biomass hard carbon material for a negative electrode of a sodium-ion battery and a preparation method of the coconut shell biomass hard carbon material, and belongs to the technical field of battery materials. The coconut shell biomass hard carbon material for the negative electrode of the sodium-ion battery is prepared by the following steps: soaking in alkali liquor and acid liquor, removing impurities, drying coconut shell powder which is washed to be neutral by utilizing a flash evaporation method to obtain a coconut shell powdery precursor, and sequentially carrying out low-temperature pre-oxidation and Joule thermal method oxygen-free high-temperature pyrolysis treatment on the coconut shell powdery precursor, so as to obtain the coconut shell biomass hard carbon material for the negative electrode of the sodium-ion battery, the coconut shell biological hard carbon negative electrode material prepared by the invention is rich in pore structure, sodium ions can be effectively de-intercalated in a negative electrode when the coconut shell biological hard carbon negative electrode material is applied to a battery, and a sodium ion battery assembled by the prepared sodium ion battery negative electrode has the advantages of high specific capacity, obvious first-effect improvement, good cycle performance and the like.

The present invention provides a preparation method and application of a hard carbon negative electrode material for a sodium ion battery, and belongs to the technical field of secondary batteries. The preparation method of the hard carbon negative electrode material for a sodium ion battery provided by the present invention comprises: mixing a carbon source precursor and an acid solution to obtain a mixed solution, allowing the mixed solution to circulate under the action of a circulating pump, completing the pickling of the carbon source precursor, filtering, washing, and drying, and then carbonizing the carbon source precursor under an inert atmosphere. The preparation method provided by the present invention can improve the effective contact between the carbon source precursor and the acid solution, greatly improve the pickling efficiency and pickling effect, and the prepared negative electrode material has excellent sodium storage performance, high reversible specific capacity and first-cycle coulomb efficiency, and the method is simple, which can greatly reduce production time and cost, and is suitable for the preparation of large-scale hard carbon negative electrode materials.

The invention discloses a preparation method of a liquid-phase oxidized starch-based hard carbon material, the hard carbon material and application of the hard carbon material, and belongs to the technical field of battery materials. Starch, an oxidizing agent and a solvent medium react in a sealed reaction kettle at the temperature of 25-90 DEG C, a reaction product is sequentially subjected to water washing, drying and carbonization, and the hard carbon material is obtained.According to the method, the starch is treated through a liquid-phase oxidation method, the problem of volume expansion occurring in the starch carbonization process can be effectively inhibited, and the yield of the hard carbon material is improved. Meanwhile, fine regulation and control on the growth process of carbon microcrystals are realized, and the obtained hard carbon material has high compaction density and low resistivity, shows excellent sodium storage performance when being used for a sodium ion battery, and has high first-circle coulombic efficiency.

The invention discloses a Co2P-coated hollow carbon sphere composite material for a sodium-ion battery negative electrode material and a preparation method thereof, and relates to the technical field of electrochemical energy storage materials.The preparation method comprises the steps that firstly, glucose, P123 and sodium oleate are dissolved in deionized water to obtain a preformed sphere precursor solution; placing the pre-balling precursor solution in a reaction kettle for hydro-thermal treatment to finally obtain a pre-carbonized carbon sphere material; respectively dissolving cobalt nitrate hexahydrate and 2-methylimidazole in a DMF (Dimethyl Formamide) solution, and mixing with the pre-carbonized carbon sphere material to obtain a carbon sphere material mixed solution with a zeolite imidazole skeleton; putting the mixed solution of the carbon sphere material with the zeolite imidazole skeleton into a reaction kettle for hydrothermal treatment to finally obtain a pre-carbonized carbon sphere material with the zeolite imidazole skeleton; and putting the pre-carbonized carbon sphere material with the zeolite imidazole skeleton and sodium hypophosphite into a tubular furnace, and simultaneously performing carbonization and phosphating treatment in an inert gas atmosphere to obtain the Co2P coated hollow carbon sphere composite material.

The invention provides a durian shell biological hard carbon material for a negative electrode of a sodium-ion battery and a preparation method of the durian shell biological hard carbon material, and belongs to the technical field of battery materials. The durian shell biological hard carbon material disclosed by the invention is prepared by the following steps: cleaning fresh durian shells, drying, crushing, soaking in alkali, soaking in acid, then washing to be neutral, carrying out low-temperature freeze-drying treatment, and then sequentially carrying out low-temperature pre-oxidation and Joule hot-process anaerobic high-temperature calcination treatment, so that the durian shell biological hard carbon material is obtained. The durian shell biological hard carbon negative electrode material prepared by the method has good sodium storage capacity, sodium ions can be effectively de-intercalated in a negative electrode when the durian shell biological hard carbon negative electrode material is applied to a battery, and a sodium ion battery assembled by the prepared sodium ion battery negative electrode has the advantages of high specific capacity, first efficiency improvement, excellent cycle performance and the like.

The invention belongs to the technical field of sodium-ion batteries, and discloses a preparation method of a hard carbon negative electrode material for a sodium-ion battery, which comprises the following steps: taking biomass as a raw material, and carrying out coarse grinding, acid treatment activation, pre-carbonization, graphite oxide compounding, fine grinding and high-temperature carbonization to obtain the hard carbon negative electrode material. Biomass is adopted as a raw material, the raw material is subjected to acid liquor activation treatment in advance, the microstructure of the carbon material is adjusted, the disorder degree and the sodium storage performance of the material are improved, meanwhile, the preparation process (activation treatment-pre-carbonization-crushing-high-temperature carbonization) is shortened, the yield is improved, and the preparation cost is further reduced; and large-scale industrial production is facilitated.

The invention discloses phenolic resin hard carbon and a preparation method and application thereof.The preparation method of the phenolic resin hard carbon comprises the following steps that S1, 3-aminophenol is dissolved in a mixed solvent to prepare a 3-aminophenol solution, and the mixed solvent is a mixed solution of 1, 6-hexanediol, 1, 4-butanediol, ethylene glycol, ethyl alcohol and water; s2, adding a formaldehyde solution into the 3-aminophenol solution, and carrying out condensation polymerization to prepare phenolic resin; and S3, performing pyrolysis on phenolic resin to prepare phenolic resin hard carbon. By adjusting the proportion of 3-aminophenol to formaldehyde, the variety and proportion of the solvent, the reaction temperature and the reaction time, the morphology and the particle size of the prepared phenolic resin microspheres can be regulated and controlled, micron-sized spherical phenolic resin is prepared, and the micron-sized spherical phenolic resin hard carbon particles have excellent sodium storage performance when being used as the negative electrode of the sodium-ion battery; high capacity, high first efficiency, high magnification and high cycle performance of the sodium ion battery are realized by preparing the phenolic resin hard carbon microspheres with proper particle size.

The invention discloses a method for preparing sodium ion hard carbon from lignin modified phenolic resin doped with S in situ, and belongs to the technical field of lignin modification, phenolic resin synthesis and sodium ion negative electrode hard carbon material preparation. Anhydrous sodium sulfite is added through a hydrothermal method, lignin is doped with an S element in situ and then is copolymerized with a phenolic prepolymer, lignin sulfonate phenolic resin is obtained, and lignin sulfonate modified phenolic resin-based hard carbon is prepared through curing and high-temperature carbonization treatment. By in-situ doping of the S element, the conductivity of the material can be improved, the specific surface area of the material is affected, the electrochemical performance of the material is improved, and oriented regulation and control of the sulfonated lignophenolic resin structure are realized. The problem of poor storage performance caused by small spacing, poor conductivity and large specific surface area of lignin phenolic resin hard carbon layers is solved.

The present invention belongs to the technical field of new energy secondary battery material processing, specifically a high carbon yield nitrogen-doped sodium ion battery hard carbon negative electrode material and a preparation method thereof. The method comprises the following steps: (1) physically mixing amino-containing biomass A, hydroxyl-containing biomass B and a cross-linking agent to obtain a uniformly mixed mixture; (2) transferring the mixture to a homogeneous reactor, performing a cross-linking reaction at a certain temperature, and obtaining a cross-linked mixture C with a stable structure; (3) performing low-temperature pretreatment and high-temperature carbonization on the cross-linked mixture C to obtain a high carbon yield nitrogen-doped sodium ion battery hard carbon negative electrode material. The hard carbon negative electrode material of the present invention has the advantages of high carbon yield, high specific capacity, good rate performance and stable cycle performance, a wide source of raw materials, low cost, and a simple preparation process. Since the carbon yield is significantly improved, the cost is significantly reduced, the production capacity is also significantly improved, the product has good technical and economic benefits, and it is easy to realize large-scale industrial production.

The invention relates to preparation of a sodium-ion battery negative electrode material, and discloses a preparation method and application of a sodium-ion battery hard carbon negative electrode material with a rich closed-pore structure. Porous carbon with a high specific surface area (more open pores) is modified by asphalt, and the modified hard carbon negative electrode material has fewer open pores and abundant closed pores, so that the low voltage (lt) of the negative electrode material can be greatly improved; 0.1 V) platform capacity, and the first coulombic efficiency of the negative electrode material is also effectively improved. The preparation method has the characteristics that the raw material asphalt is low in cost and easy to obtain, the carbon product yield is high, the preparation process method is simple, environment-friendly and the like, and large-scale industrial production is facilitated.

The invention relates to the technical field of electrode materials, and provides a preparation method and application of a nitrogen-doped closed-pore structure petroleum coke negative electrode material, and the preparation method comprises the following steps: grinding, crushing and mixing petroleum coke and an alkali activator, and then carrying out high-temperature activation pretreatment to obtain a carbon material with a developed open-pore structure; then, the carbon material with the developed open pore structure is mixed with dopamine hydrochloride, a stirring reaction is performed in an alkaline environment, polydopamine formed by polymerization of dopamine hydrochloride can block the open pore structure of the carbon material, and meanwhile, uniform nitrogen doping in petroleum coke-based porous carbon is achieved; and further performing high-temperature carbonization treatment to obtain the nitrogen-doped closed-pore structure carbon material. Through activation pore-forming and doping coating treatment, nitrogen element uniform doping and closed pore structure construction of the petroleum coke material are realized, and high sodium storage capacity and coulombic efficiency can be shown. The method provided by the invention is simple in preparation process, realizes high value-added development and utilization of petroleum coke, and has good application and development prospects.

The invention discloses a tungsten sulfide / carbon composite negative electrode material and a preparation method and application thereof, and belongs to the technical field of sodium ion battery negative electrode materials. The preparation method comprises the following steps: taking bagasse as a raw material, preparing a spherical carbon material through pretreatment, acidic hydrothermal treatment and high-temperature calcination, coating polyaniline through in-situ chemical oxidation polymerization, and then carrying out secondary polymerization and calcination to obtain a carbon matrix CNS (at) PAN (at) CS; and then carrying out hydrothermal reaction and high-temperature calcination on the carbon substrate, a tungsten source and a sulfur source, and growing WS2 nanosheets on the surface of the carbon substrate in situ to form a multi-dimensional network structure. The method is simple in process, low in cost and environment-friendly, provides a new method for large-scale application of the sodium ion battery, and has a good application prospect.

The invention provides a preparation method of a high-performance sodium storage composite material based on a carbon-coated nickel disulfide core-shell nano-box structure, and belongs to the technical field of preparation of sodium ion battery negative electrode materials. The invention aims to alleviate volume expansion of a transition metal sulfide (TMSs) electrode material in a circulation process and solve the problem of relatively poor conductivity through the design of a sodium ion battery negative electrode material structure. The preparation method comprises the following steps: firstly, carrying out electrostatic spinning on a nickel-based metal organic compound (Ni-MOC) precursor synthesized by an oil bath method, and then carrying out sulfuration treatment in an argon atmosphere to obtain the carbon-coated NiS2 core-shell nano-box structure composite material. By utilizing the unique hollow interior and protective carbon layer structure, the volume expansion of NiS2 in the charging and discharging process is effectively adapted, and meanwhile, the conductivity and structural stability of the material are remarkably improved, so that excellent electrochemical performance is obtained.

The invention discloses a hard carbon material prepared based on highland barley straw and a preparation method and application thereof, and particularly relates to the technical field of negative electrode materials. Comprising the following steps: preparing highland barley straw powder; pre-oxidizing the highland barley straw powder to obtain pre-oxidized highland barley straw powder, soaking the pre-oxidized highland barley straw powder in a phosphoric acid solution, and preparing the highland barley straw powder pretreated by phosphoric acid; sequentially activating and carbonizing the highland barley straw powder pretreated by the phosphoric acid to obtain the hard carbon material based on the highland barley straw. The obtained hard carbon material has short-range ordered graphite-like microcrystals and a rich closed-pore structure, the short-range ordered graphite-like microcrystals can promote rapid and high-density de-intercalation of sodium ions, and the closed-pore structure increases storage sites and transmission space of the sodium ions, so that the hard carbon material has excellent sodium storage performance as a negative electrode material.