128results about How to "Improve sodium storage performance" patented technology

The invention discloses a preparation method of a sodium-ion battery cathode material Na3V2(PO4)3. The method comprises the following steps: (1) mixing a sodium salt, a vandic salt, phosphate, a complexing agent, a high-molecular compound and a solvent to obtain a Na3V2(PO4)3 spinning solution; (2) carrying out electrostatic spinning on the Na3V2(PO4)3 spinning solution to obtain a Na3V2(PO4)3 spinning precursor; and (3) collecting the Na3V2(PO4)3 spinning precursor, carrying out thermal treatment on the Na3V2(PO4)3 spinning precursor in an inert atmosphere and cooling the Na3V2(PO4)3 spinning precursor to obtain the sodium-ion battery cathode material Na3V2(PO4)3. According to the sodium-ion battery cathode material Na3V2(PO4)3 prepared by the method disclosed by the invention, high-capacity charging and discharging of the battery can be realized; and the cycle stability of the battery can be improved.

The invention discloses a sodium ion battery negative electrode material and a preparation method thereof, and the preparation method comprises a preparation method (1) or a preparation method (2). The preparation method (1) is: firstly activating the soft carbon and then coating the hard carbon; the preparation method (2) is: firstly activating the hard carbon and then coating the soft carbon. The preparation method firstly introduces a large number of developed pore structures by activating the soft carbon / hard carbon to provide more storage space for sodium ions, which is favorable for theincrease of material capacity; then the coating of a hard carbon / soft carbon precursor can effectively cover the defects and edge faces caused by the activation, reduce the irreversible capacity losscaused by the insertion and removal of sodium ions, and effectively improve the first-week coulomb efficiency. The sodium ion battery negative electrode material of the invention has the advantages oflow cost, high capacity and high first-week coulomb efficiency, and high cost performance; in addition, the preparation method of the invention is simple and suitable for commercial application.

The invention belongs to the field of sodium ion battery materials, and particularly relates preparation of a high-capacity molybdenum selenide-chlorella derived carbon less-layer compound battery cathode material. The preparation comprises the steps of: firstly adding chlorella and a molybdenum source in distilled water; carrying out stirring at a room temperature for a certain time and then carrying out centrifugal drying; and further carrying out calcination and selenylation to obtain a less-layer molybdenum selenide-chlorella derived carbon compound. Results show that the sodium ion battery cathode material has excellent electrochemical property. The molybdenum selenide in the material is a less-layer structure (1-4 layers) and the distance between adjacent layers is about 0.66 nm, sothat the volume expansion in the charging / discharging process can be effectively buffered; and the chlorella derived carbon has in-situ N and P heteroatim doping, so that the less-layer molybdenum selenide structure can be effectively fixed and then the sodium storage performance is improved. The preparation is simple in process, strong in operability, wide in raw material source, low in cost andsuitable for large-scale production, and accords with environment requirements.

The invention discloses a dual-layer porous carbon nanometer tubular material and a preparation method and application thereof. The material has a coaxial dual-layer hollow tubular structure, wherein a carbon material taking high graphitized carbon as main is arranged at an inner layer, and a carbon material taking amorphous carbon as main is arranged at an outer layer. The preparation method comprises the steps of preparing a transition metal nanowire by a hydrothermal method, coating an organic carbon source on a surface of the transition metal nanowire to obtain a precursor by a liquid phase deposition method, and carbonizing and pickling the precursor to obtain the material. The method has the advantages of available raw material, simple preparation process and good repeatability, and the prepared material has relatively large inter-layer distance, rich porous structure, large specific area and favorable conductivity, shows high cycle efficiency, high specific capacity and rate performance when applied to a sodium ion battery, and has wide industrial application prospect.

The invention discloses a method for preparing a flexible MoS2 / CNFs sodium ion battery negative electrode material by combining electrostatic spinning and a hydrothermal method, and a product. The method comprises the following steps of 1) synthesizing carbon nanofibers by utilizing an electrostatic spinning technology; 2) taking the carbon nanofibers as a precursor, carrying out a hydrothermal reaction in an aqueous solution comprising a molybdenum source and a sulfur source to obtain a MoS2 / CNFs compound; and 3) performing high-temperature annealing treatment to obtain a MoS2 / CNFs compositematerial. The MoS2 / CNFs composite material is simple in preparation process, the cost is low, the processing is easy, and the method can be used for large-scale production. By virtue of the expanded layer spacing of the material and the stable three-dimensional conductive network, the electrochemical performance of the material is improved, the material can be used as a negative electrode materialof the sodium ion battery, and the transfer rate of electrons and sodium ions can be accelerated. The MoS2 / CNFs composite material is high in capacity, long in cycle life and excellent in rate performance, and has a high prospect in future commercial application.

The invention relates to an oxygen and nitrogen co-doped graded porous carbon nanosheet electrode material as well as a preparation method and an application thereof. The preparation method comprisesthe following steps: mixing animal bones, scales, shells, metal alkali or metal salt; carrying out thermal treatment in a low temperature condition of 250-650 DEG C; and then carrying out acid pickling to obtain the electrode material. The material is composed of the carbon nanosheets, has graded porous structures of micropores, mesopores and macropores, and has the characteristics of being many in defect, large in carbon interlamellar spacing, high in specific surface area, rich in doped oxygen and nitrogen atoms and the like. The electrode material serving as a cathode of a sodium ion capacitor has a high reversible capacity and excellent cycling stability and rate capability.

The invention discloses a FeS-coated Fe3O4 nanometer composite material and application of the same in a sodium ion battery negative electrode material. The FeS-coated Fe3O4 nanometer composite material comprises an inner core and an outer shell, wherein the inner core is Fe3O4, and the outer shell is FeS. The FeS-coated Fe3O4 nanometer composite material provided by the invention comprises two preparation methods, the first preparation method comprises the step of preparing the nanometer composite material by surface vulcanization, and the second preparation method comprises the step of preparing the nanometer material by surface coating. The preparation methods are simple, are low cost in raw material and uniform in morphology, and can be used for preparation on a large scale; the nanometer composite material shows excellent sodium storage performance, particularly cycle stability when used as the sodium ion battery negative electrode material, which is benefited from a synergistic effect generated by the Fe3O4 in the composite material and the FeS outside the composite material; and the nanometer composite material combines the characteristics of excellent cycle property of the Fe3O4 and high capacity of the FeS, and is the sodium ion battery negative electrode material expected to be used.

The invention discloses a carbon-coated NiS2 material, a preparation method thereof and an application thereof as a negative electrode material of a sodium ion battery. The preparation process of thecarbon-coated NiS2 material comprises the steps of synthesizing a Ni ( DMG) 2 rodlike structure through coordination reaction for butanedione oxime and nickel salt; coating the surface of the rod-shaped structure of the Ni ( DMG) 2 with polyaniline through in-situ polymerization, to obtain a Ni ( DMG) 2 rod-like structure @ polyaniline compound; mixing the Ni ( DMG) 2 rodlike structure @ polyaniline compound with the elemental sulfur, then placing them under a protective atmosphere, and carrying out calcining treatment to obtain the carbon-coated NiS2 material. The material is used as a sodium-ion battery negative electrode material, exhibiting excellent electrochemical performance, and still has a capacity of 581 mAh g / 1 after being charged and discharged at a current density of 0.1 A g-1 after 100 cycles. The preparation method of the carbon-coated NiS2 material is simple, easy to control the conditions, shorting the production cycle, lowering the cost, and is applicable to industrial production.

The invention relates to carbon-coated MoSe2 / graphene nanofibers prepared by electrospining and a preparation method thereof. The nanofibers are composed of coated carbon, MoSe2 and graphene. The preparation method comprises the following steps: dissolving water soluble molybdenum salt and a high polymer in a mixed solution of deionized water and ethylene glycol, heating the mixed solution till a stable transparent sol is formed, adding the graphene into the molybdenum salt solution to form an electrospining solution; electrospining the electrospining solution to obtain hybridized fibers; and then vacuum sintering the hybridized fibers obtained in the step 2 and zero valent selenium powder in a tubular furnace to obtain a carbon-coated MoSe2 / graphene nanofiber material. The fibers are uniform in shape and length, and MoSe2 crystals are uniformly distributed in the fibers and are coated by amorphous carbon; and the graphene as a conductive network is uniformly distributed in the fibers. According to the carbon-coated MoSe2 / graphene nanofibers provided by the invention, the raw materials are easily available, the preparation process is simple and controllable reaction conditions are mild, and the obtained product has a relatively high specific surface area, excellent conductivity and structural stability and can be used as an ideal lithium / sodium ion battery cathode material and a high performance electrocatalytic material.

The invention discloses an exotic atom-doped carbon material and a preparation method and an application thereof. The doped carbon material prepared according to the method is a honeycomb three-dimensional multi-level porous structure material, wherein macropores are constructed by mutually cross-linked flakes, the flakes are stacked by nanoparticles, and random mesopores and micropores are distributed between the nanoparticles. The preparation method comprises the steps of firstly dissolving polyacrylonitrile into an N, N-dimethylformamide solution, then adding one or more reagents containingtarget doping atoms into the solution, conducting a solvothermal reaction to obtain a precursor, placing the precursor in a protective atmosphere for calcination so as to obtain a single or multi-atom doped carbon material with uniform nanometer size and excellent electrochemical performance. Sodium-ion batteries show high specific capacity, excellent rate performance and ultra-long cycle stability when the exotic atom-doped carbon material is used as a negative electrode material of the sodium-ion batteries.

The invention provides a negative electrode material used for a sodium ion battery. The negative electrode material has a chemical formula of Ni3B2O6, an orthorhombic crystal system crystal structure and belongs to a Pnnm space group. The invention also provides a preparation method for the negative electrode material used for the sodium ion battery; a nickel source and a boron source are mixed uniformly to be calcined in an oxidization atmosphere condition; and then steps of cooling, washing and drying are performed to prepare a pure-phase nickel borate material. The negative electrode material has the characteristics of wide raw material resource, low preparation cost, simple preparation technological process, low equipment performance requirement, high product purity, high safety and the like; and when the prepared nickel borate material is applied to the sodium ion battery, high sodium storage capability and excellent electrochemical performance are shown.

The invention discloses a method for improving the sodium storage performance of a vanadium pentoxide electrode material through zinc ion pre-embedding. Firstly, commercial vanadium pentoxide (V2O5) powder is used as a vanadium source, zinc nitrate hexahydrate (Zn(NO3)2.6H2O) is used as a zinc source, hydrogen peroxide (H2O2) is used as a cosolvent, a Zn<2+> pre-embedded V2O5.nH2O precursor is prepared by combining a sol-gel method with a vacuum freeze-drying technology, and then annealing treatment is carried out in air to obtain the Zn<2+> pre-embedded V2O5.nH2O electrode material. The cyclic stability and rate capability of V2O5.nH2O serving as a sodium ion battery positive electrode material can be obviously improved through the Zn<2+> pre-embedded V2O5.nH2O, and meanwhile, the methodalso has the advantages of simple preparation method, low cost, high yield, easiness in reaction condition control and the like.

The invention discloses a sodium battery positive electrode material containing ferric acid nickel porous nanotubes and a preparation method of the sodium ion battery positive electrode materials. The preparation method includes: preparing an MIL-88B-Fe2Ni precursor with a one-step hydrothermal synthesis method and then annealing in the air to obtain porous NiFe2O4 nanotubes; mixing the porous NiFe2O4 nanotubes with Arabic gum and acetylene black to obtain the sodium ion battery positive electrode material. Coordination cooperation of organic ligands involved in reaction with Fe<3+> and Ni<2+> is applied ingeniously to form a metal-organic framework with special morphology, and the NiFe2O4 nanotubes are finally annealed in the air atmosphere; the porous NiFe2O4 nanotubes derived from the metal-organic framework serves as the sodium battery positive electrode material, and relatively high specific capacity and good cycling stability are achieved.

The invention relates to a reduced graphene oxide modified antimony trisulfide battery anode material. The battery anode material is prepared by following steps: (1) adding Sb2S3 powder into anhydrousethanol, then dispersing the solution into a graphene oxide solution, and stirring the mixed solution until the mixed solution becomes uniform and stable to obtain a precursor solution; (2) transferring the precursor solution obtained in the step (1) to a hydrothermal reactor, heating the hydrothermal reactor to carry out reactions, and cooling the reactor to the room temperature to obtain suspension; and (3) filtering the suspension obtained in the step (2), washing, and drying to obtain the target product. Compared with the prior art, an Sb2S3 nano rod is prepared by a hydrothermal method,the preparation method is simple, the process is easy to control, the raw materials are easily available, and the cost is low. The prepared reduced graphene oxide modified Sb2S3 nano composite structure has an excellent electrochemical sodium storage performance and is a good sodium ion battery anode material.

The invention discloses a preparation method of a carbon electrode material of a porous structure sodium-ion battery. The preparation method comprises the steps of firstly, washing leaves of cirsium segestum with deionized water, and carrying out freeze-drying and grinding to obtain ground dried leaves of cirsium segestum; secondly, placing an activator and the ground dried leaves of cirsium segestum into distilled water according to a mass ratio of (0.5 to 5):1, stirring to form mixed suspension, then performing a hydrothermal reaction, and after the reaction is ended, concentrating the obtained mixture to obtain a slurry product, wherein 1 to 5g of dried leaves of cirsium segestum is added into each 50ml of distilled water; then carrying out calcination on the slurry product in protective gas to obtain a calcined product; and finally, removing the activator in the calcined product, then washing the product with deionized water, and until filtrate is neutral, carrying out drying to obtain the carbon electrode material of the porous structure sodium-ion battery. The carbon material prepared by the preparation method disclosed by the invention has a large specific surface area and a unique three-dimensional pore structure, shows excellent electrochemical performance, and is simple in preparation process, low in cost and easy to implement industrialization.

The invention discloses a preparation method for a carbon-loaded iron nitride compound sodium ion battery negative electrode material doped with nitrogen. The preparation method comprises the steps of firstly, dissolving a nitrogen source, a carbon source and an iron source in deionized water according to a mass ratio being 40:1:(10-40), and performing uniform stirring, wherein 6g nitrogen source is added into the deionized water per 40mL; secondly, freezing and drying the mixture to obtain a product A; thirdly, performing pyrolysis reaction on the product A to obtain a product B; and finally, washing the product B with the deionized water and ethyl alcohol, thereby obtaining the carbon-loaded iron nitride compound sodium ion battery negative electrode material doped with the nitrogen. The product is prepared from a conventional and cheap compound by a one-step pyrolysis method, the method is simple, is low in cost and is easy to operate, and mass production is expected to be achieved.

The invention discloses a preparation method of a sodium-ion battery modified titanium dioxide-graphene anode material. The preparation method comprises following steps: 1, tetrabutyl titanate is added into absolute ethyl alcohol, a graphene aqueous solution is added, and uniform stirring is carried out at normal temperature; 2, an obtained uniformly mixed solution from step 1 is subjected to centrifugal operation so as to obtain a precipitate, and the precipitate is subjected to freeze drying so as to obtain titanium dioxide / graphene composite nanometer sheets; 3, the titanium dioxide / graphene composite nanometer sheets are subjected to high temperature phosphatization processing in a phosphorus-containing atmosphere so as to obtain phosphor doped titanium dioxide / graphene composite nanometer sheets. According to the preparation method, graphene nanometer sheets are taken as a template so as to obtain the titanium dioxide / graphene composite nanometer sheets, the electric conductivityof the composite electrode material is improved; and phosphor doping is capable of improving titanium dioxide surface sodion transmission capability, and improving the sodium storage performance of the titanium dioxide / graphene composite electrodes.

The invention belongs to the technical field of sulfide nano-materials, and discloses a preparation method and an application of cobalt sulfide having a nano-lamella assembled three-dimensional annular micro-nano structure. The preparation method comprises the following steps: dissolving CoCl2.6H2O in ethylene diamine, adding thioacetamide, transferring the above obtained solution into a reaction kettle, and washing and drying the obtained product to obtain the cobalt sulfide having a nano-lamella assembled three-dimensional annular micro-nano structure. The method has the advantages of simplicity in operation, easiness in preparation, high controllability, cheap synthesis raw materials and high yield. The cobalt sulfide having a nano-lamella assembled three-dimensional annular micro-nano structure has good electrochemical performances. The initial discharge specific capacity of the cobalt sulfide is 745 mAh / g when the current density is 100 mA / g, and the capacity of the cobalt sulfide still reaches up to 392 mAh / g after 200 cycles when the current density is 1 A / g, so the cobalt sulfide has a good cycle stability, is a sodium ion battery negative electrode material having excellent performances, and has a wide application prospect in the energy storage field.

The invention belongs to the technical field of new energies and discloses a novel negative electrode material of a sodium-ion battery as well as a preparation method and an application of the novel negative electrode material. The preparation method comprises the following steps: dissolving a carbon source and a molybdenum source in a solvent, heating to ensure a reaction to obtain a precursor Mo3(BTC)2, implementing in-situ carbonization to obtain a composition of a carbonization-molybdenum nanoparticle and an ultrathin graphene shell. The specific structure of the negative electrode material is that the carbonization-molybdenum nanoparticle is coated by the ultrathin graphene shell, wherein the diameter of the carbonization-molybdenum nanoparticle is 1-10nm. In the electrochemical reaction process of the negative electrode material with sodium, the conversion reaction with a sodium ion achieves disembedding of the sodium ion, the reversible disembedding sodium capacity, the excellent sodium storage performance, higher reversible capacity and better cycle performance are achieved, the preparation method is simple, the cost is low, the preparation method is environmentally friendly and can be applied to the sodium-ion battery, and more possibilities for the exploration of the negative electrode material of the sodium-ion battery are provided.

The invention discloses a polyimide material as well as a preparation method and application thereof. The polyimide material is generated by taking N, N-dimethylformamide, N-methylpyrrolidone and thelike as solvents and reacting anhydrides such as 1, 4, 5, 8-naphthalenetetracarboxylic dianhydride, pyromellitic dianhydride and 1, 2, 4, 5-cyclohexane tetracarboxylic dianhydride with urea. The polyimide material shows relatively high specific capacity and stable cycle index in an aqueous lithium ion half battery. In the future, the material can be matched with more mature positive electrode materials to construct a high-energy-density aqueous lithium ion total battery.

The invention discloses a preparation method for a carbon nano-sheet matrix material and an application of the carbon nano-sheet matrix material in a sodium-ion battery. The method comprises the following steps: adopting lignin, resorcinol, formaldehyde and sodium carbonate for preparing a lignin gel according to a solution method; carbonizing the lignin gel at 400-1600 DEG C; activating with magnesium chloride at 600-1000 DEG C, thereby acquiring the carbon nano-sheet matrix material. The method has the advantages that the raw materials are easily acquired, the preparation process is simple and the repeatability is high. The prepared carbon nano-sheet matrix material has the advantages of low degree of graphitization, regular sheet structure, large specific area, abundant reaction active sites, moderate interlayer spacing, high electrical conductivity, and the like. When the carbon nano-sheet matrix material is applied to the sodium-ion battery, an excellent battery performance can be presented.

The invention discloses a preparation method of an in-situ carbon conductive agent-coated tin-nickel alloy and an application of the in-situ carbon conductive agent-coated tin-nickel alloy as a cathode material for a sodium-ion battery. The method comprises the following steps: respectively dissolving stannic chloride and nickel potassium cyanide into water solutions into which a carbon conductive agent is dispersed, and then mixing the water solutions of the stannic chloride and the nickel potassium cyanide to form Sn(IV)-Ni(II) cyano coordination polymer hydrogel of the in-situ immobilized carbon conductive agent; and with a composite hydrogel system as a precursor, adding sodium borohydride as a reducing agent, reacting for 0.1-24 hours, and washing and drying a product to obtain the in-situ carbon conductive agent-coated tin-nickel alloy. The carbon conductive agent is coated with the tin-nickel alloy in situ in the composite hydrogel reduction process; and uniform distribution of the carbon conductive agent and tin-nickel alloy active materials at the nanoscale can be achieved, so that the structure stability and the charge transport capacity of the tin-nickel alloy as the cathode material for the sodium-ion battery are effectively improved.

The invention discloses a selenium-coated tin dioxide / graphene nano composite material and an application thereof in a cathode material of a sodium-ion battery. The selenium-coated tin dioxide / graphene nano composite material is characterized in that 1) two types of SnO2 of different crystal phases (SnO2 of a tetragonal system and SnO2 of an orthorhombic system) tightly grow together to form nanoscale particles; 2) the formed nanoscale particles are uniformly combined on the surface of three-dimensional graphene; and 3) unordered selenium uniformly coats the surface of the tin dioxide / graphenenano structure. The selenium-coated tin dioxide / graphene nano composite material provided by the invention is simple in preparation method, cheap in raw material and uniform in shape, can be preparedon a large scale, and shows an excellent sodium storage property as the cathode material of the sodium-ion battery, benefited by the selenium coating. The two tin dioxide heterostructures in the composite material and the three-dimensional conducting network of graphene have a synergistic effect, so that the material is quite expected to be applied to the cathode material of the sodium-ion battery.

The invention provides a bimetallic selenide carbon microsphere composite material as well as a preparation method and application thereof. In the bimetallic selenide carbon microsphere composite material, two kinds of metal selenide are cross-linked with each other through the carbon matrix and are uniformly combined to form microspheres; in the two kinds of metal selenide, the metal valence state of one is relatively high, and the metal valence state of the other is relatively low. By introducing the high-valence metal, the electron and ion transmission effect of the low-valence metal can be improved, and the synergistic effect of the double metals is generated, so that the activity and the sodium storage performance of the material are improved. The carbon matrix not only provides a conductive network, but also limits the volume expansion of the material.

The invention discloses a method for improving sodium storage performance of vanadium pentoxide electrode material through copper ion pre-embedding. The method comprises the following steps of firstly, taking commercial vanadium pentoxide (V2O5) powder as a vanadium source, taking copper nitrate trihydrate as a copper source, taking hydrogen peroxide as a cosolvent, and preparing Cu2+ pre-embeddedV2O5.nH2O precursor through a sol-gel method by combination of a vacuum freeze-drying technology; and next, carrying out annealing treatment in the air to obtain a Cu2+ pre-embedded V2O5.nH2O electrode material. Through Cu2+ pre-embedded V2O5.nH2O, the sodium storage performance of the V2O5.nH2O electrode material can be obviously improved. When the prepared Cu2+ pre-embedded V2O5.nH2O electrodematerial is used as the positive electrode material of a sodium ion battery, relatively high rate capability and cycling stability are shown; and meanwhile, the method also has the advantages of beingsimple in preparation method, low in cost, high in yield, easy to control reaction conditions and the like.

The invention specifically discloses a three-dimensional porous carbon material, belonging to the field of sodium ion battery materials. The three-dimensional porous carbon material is composed of carbon nanosheets and has a specific surface area of 100-2000 m<2> / g, and the thickness of the carbon nanosheets is in a range of 10-100 nm. The invention also discloses a preparation method for the three-dimensional porous carbon material. The preparation method comprises the following steps: subjecting dopamine and montmorillonite to a polymerization reaction in a solution to obtain a precursor;subjecting the precursor to heat treatment and washing to obtain a layered carbon nanosheet material; and subjecting the layered carbon nanosheet material to a hydrothermal reaction in a solution witha positive surfactant dissolved therein, and then carbonizing a hydrothermal reaction product so as to obtain the three-dimensional porous carbon material. The method uses easily available raw materials, is simple in preparation process and has good repeatability; and the prepared three-dimensional porous carbon material has the advantages of rich pores, a high degree of cross-linking, stable structure, a large specific surface area, good conductivity and the like, and shows good battery performance when applied to sodium ion batteries.

The invention provides a preparation method of a hollow carbon nanosphere confinement tin nanocluster composite material, and belongs to the technical field of new materials. The method comprises the following steps: S1, uniformly dispersing stannous chloride dihydrate and thiourea in a water solvent to obtain stannic oxide sol; S2, uniformly dispersing a reaction monomer, a surfactant and the stannic oxide sol prepared in S1 into a water solvent, and performing polymerization reaction under the condition of 0 DEG C and the action of an initiator to prepare a hollow polymer loaded stannic oxide precursor; and S3, in an inert gas or nitrogen atmosphere, the precursor is subjected to carbonization treatment, and the hollow carbon nanosphere confined tin nanocluster composite material is obtained. The superfine tin nano-cluster is successfully confined to the hollow carbon nanosphere wall through the micelle interfacial polymerization technology, and the method has the advantages that the steps are simple and convenient, the loaded tin nano-particles are fine and uniform, and the method is environmentally friendly.

The invention discloses a preparation method for a vanadium pentoxide / graphene composite positive electrode material of a high-performance sodium ion battery. The commercial vanadium pentoxide (V2O5)powder is used as a vanadium source, graphene aqueous dispersion liquid is used as a composite material, hydrogen peroxide (H2O2) is used as a cosolvent, and sol-sol is adopted. The preparation methodcomprises the following steps: preparing a V2O5*NH2O / graphene composite electrode material precursor by combining a sol-gel method with a vacuum freeze-drying technology, and then carrying out annealing treatment in air to obtain the V2O5*NH2O / graphene composite electrode material. The in-situ compounding method is adopted, so that graphene is uniformly distributed between V2O5*NH2O material layers. The method has the advantages that the sodium storage performance is good, the preparation method is simple, the cost is low, the yield is high, the reaction conditions are easy to control, and the like.

The invention discloses a tremella-shaped nanosphere material assembled by inlaying molybdenum dioxide nanoparticles into carbon nanosheets, preparation of the tremella-shaped nanosphere material andapplication of the tremella-shaped nanosphere material in a sodium ion battery. In the material, MoO2 nanoparticles are inlaid in amorphous carbon nanosheets, the carbon nanosheets are interwoven andassembled into tremella-shaped nanospheres, and a large number of mesopores and other pores exist between the carbon nanosheets. The preparation method comprises the following steps of polymerizing ammonium molybdate and dopamine hydrochloride to form a precursor, and calcining to decompose and carbonize, thereby obtaining the final product. The electrochemical activity, the structural stability and the cycling stability of MoO2 can be improved, so that MoO2 has higher specific capacity and more stable cycling performance. The tremella-shaped nanosphere assembled by inlaying MoO2 nanoparticlesinto carbon nanosheets has a remarkable application value when being used as an electrode material of a sodium-ion battery.

The invention relates to an in-situ carbon-coating hexagon K0.7[Fe0.5Mn0.5]O2 nano material as well as a preparation method and an application thereof. The material can serve as a sodium-ion battery positive active material which is formed by coating K0.7[Fe0.5Mn0.5]O2 hexagonal nano crystals with graphitized carbon layers; the diameter of the hexagonal nano crystals is 100-350nm; the thickness of the graphitized carbon layers is 6-10nm. The in-situ carbon-coating hexagon K0.7[Fe0.5Mn0.5]O2 nano material has the beneficial effects that the nano material with relatively uniform shape is finally prepared by combining methods of drying solutions and calcinating atmosphere; the material serves as a sodium-ion battery positive material active substance and shows relatively high specific discharge capacity and excellent cycling stability; on the other hand, the process is simple; the in-situ carbon-coating hexagon K0.7[Fe0.5Mn0.5]O2 nano material is prepared by simply drying and calcinating the solution; the energy consumption is relatively low.