153 results about "Vanadium phosphate" patented technology

The invention discloses a carbon-coated high-entropy NASICON positive electrode material as well as a preparation method and application thereof, and belongs to the technical field of sodium ion battery electrode materials. The method comprises the following steps: adding a vanadium source, a carbon source, a chromium source, an iron source, a manganese source, a zinc source, an aluminum source, a sodium source and a phosphorus source into deionized water, heating and dissolving to obtain a clear solution; and heating the solution to form gel, and then carrying out the steps of vacuum drying, crushing, pre-sintering, calcining and the like to obtain the Na3V2-y (CrFeMnZnAl) y (PO4) 3 / C (0 < y < 1) positive electrode material. The positive electrode material has a stable NASICON structure, and the morphology is of a scaly structure. According to the invention, a high-entropy doping mode is adopted to replace part of vanadium sites in sodium vanadium phosphate, and the conductivity of the positive electrode material is improved through carbon coating, so that the prepared positive electrode material has relatively good cycling stability and rate capability.

The invention discloses a composite positive electrode material for realizing sodium ion internal compensation based on electrochemical potential difference as well as a preparation method and application thereof, relates to a sodium ion battery composite positive electrode material as well as a preparation method and application thereof, and aims at solving the problems of polarization increase, capacity reduction and poor rate capability of the existing sodium ion battery positive electrode material at the discharge end and in a low-temperature environment. The composite positive electrode material is formed by compounding a main phase material A and an auxiliary phase material B with the electrochemical potential higher than that of the main phase material A in a physical mode; at the final stage of discharge or at low temperature and high rate, the auxiliary phase spontaneously releases sodium ions to the main phase based on the electrochemical potential difference of the two phases without the action of an external electric field, and the available capacity of the main phase is improved through internal compensation. The specific discharge capacity of the sodium vanadium fluorophosphate and sodium vanadium phosphate composite material is 119.2 mAh g <-1 >, the specific discharge capacities of the sodium vanadium fluorophosphate and sodium vanadium phosphate composite material are 76.4 mAh g <-1 > and 107.4 mAh g <-1 > at the multiplying power of 30 C and the multiplying power of-20 DEG C and the multiplying power of 0.1 C, and the sodium vanadium fluorophosphate and sodium vanadium phosphate composite material can be applied to the field of sodium ion batteries.

A method for preparing sodium vanadium fluorophosphate as a positive electrode material for sodium-ion batteries on the basis of spray drying, which method aims to solve the problems of poor electronic conductivity and fluorine loss in sodium vanadium fluorophosphate as a positive electrode material for sodium-ion batteries. The method comprises dissolving a carbon source, a phosphorus source, a sodium source and a vanadium source in water, and then drying same in a spray dryer to obtain a precursor powder; and then uniformly mixing the precursor powder with a fluorine source, and calcining the resulting mixture for 3-6 h to obtain sodium vanadium fluorophosphate, namely, a positive electrode material for sodium ion batteries. The material is made of micron spherical particles having a core-shell structure, the particle size is about 8 μm, the shell thickness is about 200 nm, the initial specific discharge capacity is 110.60 mAh / g at a rate of 1 C, and the specific discharge capacities are 97.90 mAh / g and 74.70 mAh / g at rates of 10 C and 30 C, respectively. The present invention can be used in the field of sodium-ion batteries.

The invention provides a sodium vanadium fluorophosphate positive electrode material and a preparation method and application thereof, and belongs to the technical field of sodium ion battery positive electrode materials. The preparation method comprises the following steps: mixing sodium salt, a vanadium source, a phosphorus source, villiaumite and a carbon source in water, obtaining xerogel by adopting a sol-gel method, calcining to obtain a carbon-coated sodium vanadium fluorophosphate positive electrode material, dispersing the carbon-coated sodium vanadium fluorophosphate positive electrode material in water to form a suspension, adding polyvinyl alcohol and manganese salt, uniformly stirring, heating to evaporate a solvent, and annealing in inert gas to obtain the carbon-coated sodium vanadium fluorophosphate positive electrode material. The carbon and manganese dioxide synergistically co-coated sodium vanadium fluorophosphate positive electrode material is obtained. A sol-gel method and a suspension coating technology are combined to construct the carbon and manganese dioxide dual-coated NVPF composite material, so that the problems of slow sodium ion diffusion kinetics, low electronic conductivity, interface side reaction and the like when the NVPF is used as a sodium ion battery positive electrode material are solved.

The invention belongs to the technical field of battery materials, and relates to a double-layer coated sodium vanadium phosphate positive electrode material as well as a preparation method and application thereof. The invention provides the double-layer coated sodium vanadium phosphate positive electrode material, the innovative design of the double-layer coated sodium vanadium phosphate positive electrode material remarkably improves the performance of the existing aqueous battery, and particularly provides an effective solution for the problems of short cycle life and low capacity of the traditional aqueous battery. The novel positive electrode material is composed of a sodium vanadium phosphate inner core, an aluminum oxide coating layer and a carbon coating layer, the electrochemical performance of the sodium vanadium phosphate inner core is further optimized by doping metal, so that the material not only has higher structural stability, but also can effectively improve the charge-discharge efficiency and capacity.

The application provides a preparation method of sodium vanadium fluorophosphate, which comprises the following steps: mixing a sodium source, a vanadium source, a phosphorus source and a fluorine source to form a first raw material, wherein the molar ratio of sodium element, vanadium element, phosphorus element and fluorine element in the first raw material is a:b:c:d, wherein a, b, c and d are real numbers greater than 0, and a / c≤1.5, a / b<1.5, a / d<1, or a / c≥1.5, c / b<1 and c / d<2 / 3; the first raw material is treated to obtain a first precursor; and the first precursor is dried and calcined to obtain sodium vanadium fluorophosphate. The preparation method can be used to prepare sodium vanadium fluorophosphate with few impurities, high purity and excellent performance, and is helpful to the use of sodium vanadium fluorophosphate. The application further provides a preparation method and application of carbon-coated sodium vanadium fluorophosphate.

The invention discloses a high-stability gel polymer electrolyte as well as a preparation method and application thereof, and relates to the technical field of metal batteries. The preparation method comprises the following steps: mixing a metal salt and a solvent to obtain a basic electrolyte; adding butyl acrylate, triallyl isocyanurate, a plasticizer and an initiator into the basic electrolyte to obtain a precursor solution; and carrying out polymerization reaction on the precursor solution to obtain the high-stability gel polymer electrolyte. The prepared gel polymer electrolyte has the characteristics of high ionic conductivity and high strength, and can be applied to a lithium metal battery and a sodium metal battery. The NVP gel polymer electrolyte Na metal battery assembled by adopting a polyanion positive electrode sodium vanadium phosphate (NVP), a sodium metal negative electrode and the gel polymer electrolyte disclosed by the invention can realize long cycle stability under high magnification.

The present application uses sodium source, vanadium source, reducing acid and phosphoric acid as raw materials, synthesizes Na(VO)2(PO4)2.4H2O through wet ball milling, and then obtains layered vanadium phosphate-based positive electrode material Na(VO)2(PO4)2 after low-temperature sintering of the synthesized material. The present application realizes synthesis of pure-phase layered vanadium phosphate-based positive electrode material Na(VO)2(PO4)2 at room temperature. Compared with other phosphate positive electrode materials, the material has obviously improved electrical conductivity, shows excellent discharge capacity without carbon coating, and the synthesis method has low synthesis temperature, simple operation, low cost, strong controllability, good repeatability and suitability for industrial production.

The invention discloses a preparation method of a soft-hard carbon coated sodium vanadium phosphate composite material and application of the soft-hard carbon coated sodium vanadium phosphate composite material in a sodium ion battery. The preparation method of the composite material comprises the following steps: mixing a sodium source, a vanadium source, a phosphorus source, a soft carbon source and a hard carbon source together, carrying out ball milling, and then carrying out high-temperature calcination to obtain the soft-hard carbon coated sodium vanadium phosphate composite material. The soft carbon can be used as a high-quality conducting medium for charge transfer, the hard carbon can provide defects to accelerate the sodium ion migration rate, and the electrochemical performance of the material can be improved under the synergistic effect of the soft-hard carbon. The composite material as a sodium ion battery positive electrode material has excellent electrochemical performance, and the preparation method is simple, short in process and low in cost, and has a great commercialization prospect.

The invention relates to the technical field of lithium batteries, in particular to a modified lithium iron phosphate positive active material, a preparation method thereof and a lithium battery. The modified lithium iron phosphate positive electrode active material comprises a main crystal phase, a conductive second phase dispersed and distributed at the crystal boundary of the main crystal phase, and a carbon coating layer located on the outer surface and coating the main crystal phase and the conductive second phase; the main crystalline phase material is lithium iron phosphate with an olivine structure; the conductive second phase material is lithium vanadium phosphate; the lithium battery disclosed by the invention adopts a modified lithium iron phosphate positive electrode active material which takes LiFeP as a main crystal phase, coexists with an L (P) conductive second phase and is externally coated with a low-content thin carbon layer, and is matched with a high-temperature stable electrolyte containing lithium difluorophosphate and / or lithium difluoro (oxalato) borate, lithium hexafluorophosphate and organophosphate; the problem of considering high rate and high-temperature storage safety of the lithium battery is solved synergistically from two aspects of a material phase structure and an electrolyte.

This invention provides a sodium vanadium phosphate composite material with a three-dimensional carbon network structure, its preparation method, and its application, relating to the field of sodium-ion battery electrode materials technology. The preparation method is as follows: vanadium source, sodium source, phosphorus source, reducing agent, and anhydrous ethanol are mixed and ground to obtain a mixed slurry; the mixed slurry is subjected to alternating solvothermal treatment and ball milling, followed by carbonization to obtain a sodium vanadium phosphate composite material with both surface carbon coating and an internal three-dimensional carbon skeleton. Solvothermal treatment coats the exterior with a carbon layer, while ball milling encapsulates a carbon conductive network within the sodium vanadium phosphate material. The alternating hydrothermal and ball milling processes, supplemented by solid-phase carbonization, cause the sodium vanadium phosphate particles to knead together, forming a three-dimensional conductive network on both the surface and inside the sodium vanadium phosphate grains. This not only improves the poor conductivity of sodium vanadium phosphate but also reduces the grain size, improves structural stability, and enhances the material's initial efficiency, specific capacity, and cycle life.

Described herein are carbon-coated sodium vanadium phosphate (NVP-C) microspheres, methods of synthesizing same, and batteries including same.

The invention discloses a lithium-sodium mixed positive pole piece, a preparation method thereof and a lithium metal battery, and belongs to the technical field of lithium batteries. The lithium-sodium mixed positive pole piece provided by the invention comprises a current collector and an active substance layer arranged on the current collector, the active material layer comprises a positive active material, a binder and a conductive agent; the positive active material comprises nickel cobalt lithium manganate and sodium vanadium phosphate, and the mass ratio of the nickel cobalt lithium manganate to the sodium vanadium phosphate is (60-92): (8-40). The lithium-sodium mixed positive electrode system constructed by the invention has a remarkable synergistic effect, not only has the advantages of high energy density and high power output of nickel cobalt lithium manganate, but also introduces excellent structural stability and safety characteristics of sodium vanadium phosphate, so that the finally prepared lithium metal battery has good low-temperature cycle performance, rate capability and safety performance.

The invention relates to a positive active material, a preparation method thereof and a battery, and belongs to the technical field of batteries. V ions in the lithium ferrovanadium phosphate active material enter LFP crystal lattices through doping to replace Fe < 2 + > sites to form lattice defects, and in order to maintain electric neutrality, the system spontaneously generates additional free electrons, so that the electronic conductivity is increased, and the rate performance of the lithium ferrovanadium phosphate active material applied to a battery is facilitated. And meanwhile, on the basis of doping the V element, the mass content of iron phosphide in the lithium ferrovanadium phosphate active material is controlled to be less than or equal to 800ppb, so that the probability of side reaction with an electrolyte when the lithium ferrovanadium phosphate active material is applied to a battery can be reduced, and the cycle performance is facilitated. And the lithium iron vanadium phosphate active material has two particles with specific volume median particle sizes, so that a relatively good particle size grading relationship can be formed, the lithium iron vanadium phosphate active material has relatively high compaction density, and the volume energy density of the lithium iron vanadium phosphate active material when the lithium iron vanadium phosphate active material is applied to a battery is facilitated.

The invention relates to a preparation method of a phosphorus defect bimetallic oxygen evolution catalyst. The preparation method comprises the following steps: S1, dissolving 2.4 mmol of nickel chloride hexahydrate, 0.8 mmol of vanadium chloride and 300mg of urea in 80ml of deionized water, and uniformly stirring for 10 minutes; s2, putting a product obtained in the step S1 and foamed nickel into a 100ml reaction kettle, reacting at 120 DEG C for 12 hours, and drying in a drying box after reaction; s3, putting the product in S2 and 0.8 g of sodium dihydrogen phosphate into a tubular furnace, heating to 350 DEG C at a heating rate of 3 DEG C / min in an argon atmosphere, and reacting for 3 hours to obtain nickel vanadium phosphide loaded foamed nickel; and S4, the product obtained in the S3 is put into a sodium borohydride solution to be soaked for 30 min, the product is taken out and dried, and a final product, namely the nickel vanadium phosphide loaded foamed nickel with the vacancy defect, is obtained.

A process for producing a nitrogen-doped peony-shaped molybdenum oxide, comprising the following steps: (1) adding a regulator to a molybdenum-containing solution for reacting, concentrating and thermally treating to obtain a peony-shaped molybdenum oxide; and (2) dissolving the peony-shaped molybdenum oxide in a conditioning agent and adding an amine source for standing, centrifuging, washing, and heat-treating, thereby obtaining the nitrogen-doped peony-shaped molybdenum oxide; wherein the regulator is at least one of the following: nitric acid, ammonium nitrate, sodium persulfate, ammonium persulfate, concentrated sulfuric acid, H2O2, ozone, sodium hypochlorite, wherein in step (2), the conditioning agent is at least one of the following: sodium acetate, ammonium acetate, sodium formate, diaminoethane, sodium oxalate, ammonium benzoate, sodium phenylacetate, sodium propionate, sodium tartrate, sodium citrate, ammonium citrate; and wherein in step (2) the amine source is at least one of the following: aniline, dimethylamine, trimethylamine, benzylamine, phenethylamine, ethylamine, diethylamine, propylamine, phenylenediamine, xylylenediamine, amphetamine.

The present invention provides lithium vanadium phosphate which is a single phase as seen in X-ray diffraction, particularly useful as a positive electrode active material for a lithium secondary battery or the like, by an industrially advantageous method. The present invention is a method for producing lithium vanadium phosphate having a sodium superion conductor (NASICON) structure, the method being characterized by comprising: a first step for preparing a mixed slurry by mixing a tetravalent or pentavalent vanadium compound, a phosphorus source, and a reducing sugar in an aqueous solvent; a second step in which the mixed slurry is heated and solubilized; a third step of adding a lithium source to the solution to prepare a raw material mixed solution; a fourth step for obtaining a reaction precursor by spray-drying the raw material mixed solution; and a fifth step in which the reaction precursor is subsequently fired at 500-1300 DEG C in an inert gas atmosphere or a reducing atmosphere.

The application provides an active material, a preparation method thereof, a lithium ion battery and a preparation method thereof. The active material comprises an inner core and a coating layer coated on at least part of the surface of the inner core; wherein the inner core comprises lithium vanadium phosphate, and the coating layer comprises a solid electrolyte material. In the lithium ion battery, a double-electrode lithium ion battery is constructed by taking lithium vanadium phosphate as the inner core of the active material, so that the lithium ion battery has good safety; and by coating the coating layer comprising the solid electrolyte material on the surface of the inner core of the active material, the electrochemical performance of the double-electrode lithium ion battery is improved.

The invention discloses a coated modified sodium vanadium phosphate composite positive electrode material as well as a preparation method and application thereof, and belongs to the technical field of sodium ion battery positive electrode materials. The coated modified sodium vanadium phosphate composite positive electrode material comprises a core material and a modified carbon source layer coated on the surface of the core material, and the coated modified sodium vanadium phosphate composite positive electrode material is spherical particles; the core material comprises sodium vanadium phosphate and a doped metal source, the metal source comprises alkaline earth metal and transition metal, the alkaline earth metal is selected from at least one of Mg, Ca and Sr, and the transition metal is selected from at least one of Fe, Mn, Co and Ni. The core of the coated modified sodium vanadium phosphate composite positive electrode material contains alkaline earth metal ions and transition metal elements which have a synergistic effect, so that crystal lattices in the composite positive electrode material are kept stable, and crystal lattice distortion in a circulation process can be inhibited; meanwhile, a carbon source in the modified carbon source layer is modified, so that the interfacial compatibility among the components is improved, and the cycling stability is further improved.

The present invention relates to a method for preparing a nanometer sodium vanadium phosphate material, comprising the following preparation steps: 1) weighing raw materials, the raw materials consisting of a tetravalent vanadium compound, a sodium phosphate salt and sodium fluoride, or the raw materials consisting of a tetravalent vanadium compound and a sodium phosphate salt; and 2) placing the raw materials in a high-speed homogenizing mill to complete a rapid nucleation process and control a crystal growth process. The present invention takes use of the principle of atom economy, and uses the milling device having a high power and a high rotation speed to perform efficient preparation of the nanometer sodium vanadium phosphate. The present invention achieves efficient atom utilization of the raw materials, and avoids generation of unnecessary waste materials and waste of the raw materials, which omits waste liquid treatment steps involved in solvent emission and washing processes, thereby achieving green preparation. On the basis of the milling device having a high power and a high rotation speed, high-speed collision is achieved to accelerate the reaction and to efficiently control the particle size of the product, thereby achieving nano-scale preparation. The present invention has the advantages of simple operation, high efficiency, easy industrial scale-up production and the like and helps to promote the research, popularization and application of the sodium vanadium phosphate material in the field of electrochemical energy storage.

A coated cathode material for lithium-ion batteries is disclosed. Methods and systems are further provided for applying a coating to an active cathode material for use in a lithium-ion battery. In one example, the coated cathode material may include a high-nickel content active cathode material, such as lithium nickel manganese cobalt oxide or lithium nickel aluminum cobalt oxide, coated with a coating including one or more high energy density active materials, such as lithium vanadium fluorophosphate and / or a lithium iron manganese phosphate compound. In some examples, the high-nickel content active cathode material may include greater than or equal to 60% nickel content.

The invention discloses a preparation method of monoclinic sodium vanadium fluorophosphate, which comprises the following steps: mixing carbon-coated sodium vanadium phosphate as a crystal nucleus with a solid vanadium fluoride raw material at high temperature (gt; (800 DEG C) vanadium fluoride is converted into a gaseous state, and the gaseous state and carbon-coated sodium vanadium phosphate are subjected to a chemical vapor deposition reaction to obtain a reaction product containing the monoclinic sodium vanadium fluorophosphate material; the synthesis method disclosed by the invention is simple and convenient, and effectively solves the problem of generation of an impurity phase caused by extremely easy loss of fluorine elements in a high-temperature calcination stage in a traditional solid-phase reaction process; meanwhile, a reaction mechanism is simple, conditions are controllable, and the prepared monoclinic sodium vanadium fluorophosphate material is good in consistency and high in purity; in conclusion, the obtained material has relatively high specific discharge capacity and excellent rate capability, so that the preparation method of the high-performance monoclinic sodium vanadium fluorophosphate material has a good application prospect in preparation of a sodium-ion battery material.

The invention discloses a manganese and polyanion (SiO4 / SO4) synergistically doped modified sodium vanadium phosphate composite material, a preparation method and application in a sodium ion battery positive electrode. The chemical general formula of the catalyst is Na < 3 + > x-h + kV < 2-k > Mnk (PO4) < 3-x-h > (SiO4) x (SO4) h / C, 0, hgt; 0, kgt; (x-h + k) is greater than or equal to-0.2 and less than or equal to 0.5; mn replaces a V site, SiO4 and SO4 partially replace a PO4 site in a compounding manner, and C is a carbon coating layer covering the surfaces of the particles. On the premise of ensuring the safety and large-scale preparation, the electronic conductivity of the material is improved, the charge transfer impedance is reduced, the Na < + > diffusion channel is optimized, and the structure recession is inhibited.

The application relates to the technical field of sodium-ion batteries, in particular to a sodium polyacrylate supported sodium vanadium phosphate positive electrode material and a preparation method and application thereof, which comprises the following steps: S1: polyacrylate sodium is added into deionized water I to obtain a polyacrylate sodium dispersion liquid; S2: a vanadium source is added into deionized water II to be stirred until the vanadium source is dissolved to obtain a vanadium source solution; S3: a reducing agent is added into the vanadium source solution to be reduced, then a sodium source and a phosphorus source are added and uniformly mixed to carry out a sol-gel reaction, so that a precursor solution is obtained; S4: the polyacrylate sodium dispersion liquid obtained in S1 is added into the precursor solution obtained in S3, and the solution is stirred to be adjusted to be weakly alkaline; S5: the obtained weakly alkaline precursor solution is dried to obtain a dried precursor; S6: the obtained dried precursor is placed into an inert atmosphere to be calcined at high temperature, so that the target product is obtained; the problems that the existing sodium vanadium phosphate material is limited in rate performance due to low electronic conductivity and low ionic conductivity are solved.

The invention relates to the technical field of lithium ion batteries, and discloses a lithium vanadium phosphate positive electrode material and a preparation method and application thereof, the lithium vanadium phosphate positive electrode material is an erbium-doped Li3V2 (PO4) 3 / C material, the structural formula of the lithium vanadium phosphate positive electrode material is Li3V2-xErx (PO4) 3 / C, and x is more than 0 and less than or equal to 0.12. The preparation method of the lithium vanadium phosphate positive electrode material comprises the following steps: (1) mixing lithium dihydrogen phosphate, a vanadium source, an erbium source and a carbon source to obtain a mixture; (2) carrying out ball milling on the mixture, and then carrying out drying treatment to obtain a dried material; and (3) sintering the dried material to obtain the lithium vanadium phosphate positive electrode material. According to the invention, the Li3V2 (PO4) 3 / C material is used as a basis and is doped with the erbium element to obtain the Li3V2-xErx (PO4) 3 / C material, and the erbium-doped Li3V2 (PO4) 3 / C material does not influence the crystal structure, the morphology, the particle size and the like, and can effectively improve the electronic conductivity, the specific discharge capacity and the cycling stability of the Li3V2 (PO4) 3 / C material, so that the Li3V2 (PO4) 3 / C material has better electrochemical performance.

The application discloses a kind of sodium vanadium phosphate positive electrode material, positive electrode sheet and preparation method, application thereof.The preparation method of the sodium vanadium phosphate positive electrode material mainly includes the following steps: (1) vanadium source, organic alkaline substance and ethanol are mixed, precursor is prepared by microwave method;(2) the mixture of precursor and sodium source, phosphorus source is calcined, and the sodium vanadium phosphate positive electrode material prepared by the application has one-dimensional nanowire structure, which is beneficial to optimize ion conductivity, when it is applied to battery, the battery has low internal resistance, high energy density, good rate performance and cycle performance.The raw materials used in the application are relatively cheap and easy to obtain, and the production time is significantly shortened, easy to realize, and has industrial application prospect.

The application belongs to the technical field of sodium ion battery electrode material preparation, and discloses a preparation method of a size-controllable sodium vanadium fluorophosphate-carbon composite positive electrode material, and the preparation steps comprise the following: firstly, an ionic liquid and carbon material mixed dispersion liquid is obtained through ultrasonic, then a sodium source, a vanadium source, a phosphorus source, a fluorine source and citric acid are added into the dispersion liquid, and after constant temperature stirring, a hydrothermal reaction is carried out, then solid-liquid separation, washing, drying and calcination are carried out, and the sodium vanadium fluorophosphate-carbon composite positive electrode material is obtained. + The application effectively solves the problem of large size of sodium vanadium fluorophosphate in the crystal growth process, and obtains small-sized sodium vanadium fluorophosphate, and the small particle size can shorten the Na + diffusion path and improve the performance of the material in the battery cycle process.

The invention discloses a sodium vanadium oxyfluorophosphate single crystal array self-supporting electrode and a preparation method and application thereof. A vanadium source and a carbon source are heated and reduced in a solvent, and then a sodium source, a phosphorus source and a fluorine source are added and stirred and mixed uniformly. A one-dimensional carbon material is added and ultrasonically dispersed to form a carbon film by filtration. The carbon film is hydroheated at 120-200° C. for 1-50 hours, and the obtained sodium vanadium oxyfluorophosphate single crystal array is annealed at 350-800° C. for 0.1-50 hours in an inert atmosphere to obtain an amorphous carbon-coated sodium vanadium oxyfluorophosphate single crystal array self-supporting electrode. The self-supporting electrode improves the energy density of the sodium vanadium fluorophosphate electrode through an electrode integration strategy of a single crystal array self-supporting structure and a flexible carbon material substrate, and changes the rigidity characteristics of a traditional electrode, which is of great significance for the application of the electrode in high-energy-density and flexible sodium-ion batteries.

The invention relates to the technical field of sodium ion positive electrode materials, in particular to a sodium vanadium phosphate composite positive electrode material and a preparation method thereof. The composite positive electrode material is Na < 3.1 > V2 (PO4) 2.9 (SiO4) 0.1 (at) NC-x, the sodium vanadium phosphate composite positive electrode material has a graded porous coralline structure, and mesopores and through pore channels are formed in the coralline structure. The sodium vanadium phosphate composite positive electrode material effectively widens the migration channel of sodium ions, enhances the structural stability of the material, constructs the nitrogen-doped amorphous carbon coating layer with moderate and uniform thickness, synergistically inhibits the corrosion of electrolyte and buffers the volume change, maintains high specific capacity, and also has a good application prospect. The problems of poor interface stability and ultra-high rate bottleneck are solved, and the electrochemical performance is good.