201 results about "Vanadium phosphate" patented technology

The invention provides a lithium iron phosphate composite material and a preparation method thereof, a positive pole piece and a secondary battery, the lithium iron phosphate composite material comprises a core layer, the core layer comprises an inner core, a coating layer coating the inner core, and a mutual doping layer located between the coating layer and the inner core; wherein the material of the inner core comprises lithium iron phosphate, the material of the coating layer comprises sodium vanadium fluorophosphate, and the material of the mutual doping layer comprises vanadium-doped lithium iron phosphate. A core layer of the lithium iron phosphate composite material adopts lithium iron phosphate as an inner core, the inner core is coated with sodium vanadium fluorophosphate, and a mutual doping layer structure is arranged between the inner core and a coating layer, so that mixed migration of Li / Na ions is realized, and meanwhile, the lithium iron phosphate composite material has excellent ion diffusion efficiency, relatively high theoretical specific capacity and a relatively high voltage platform; the material has low powder resistivity, a stable charge-discharge platform and excellent cycle performance, and the electrochemical performance such as energy density and cycle performance is effectively improved.

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 preparation method of a sodium ferromanganese vanadium phosphate material of a sodium battery positive electrode. The preparation method comprises the following steps: S1, preparing a hydrophosphate solution and a manganous salt solution; and S2, adding the hydrophosphate solution into the manganous salt solution, and reacting to obtain the manganous hydrogen phosphate crystal nucleus slurry. And S3, filtering and washing the manganese hydrogen phosphate crystal nucleus slurry, adding water into the manganese hydrogen phosphate material to prepare slurry, heating to 85-95 DEG C, respectively adding a ferrous source and a phosphorus salt solution, and reacting to obtain the manganese iron hydrogen phosphate slurry. And S4, filtering, washing and drying the iron manganese hydrogen phosphate slurry, adding water into the dried slurry to prepare slurry, adding phosphoric acid, heating to 90-100 DEG C, reacting to obtain an iron manganese phosphate compound precipitate, and filtering, washing and drying the precipitate to obtain an iron manganese phosphate material. The sodium manganese iron vanadium phosphate product is prepared by adopting a coprecipitation method and high-temperature sintering, and the method has the advantages of short process flow, simple process, only one-time sintering, low energy consumption and the like.

The invention provides a sodium vanadium fluorophosphate in-situ coated sodium ferric sulfate / carbon composite material and a preparation method thereof.The preparation method comprises the steps that raw materials including a reducing agent, an iron source, a sodium source and a carbon source are added into absolute ethyl alcohol to be stirred, sanded and mixed, and after obtained slurry is subjected to spray drying, the slurry is sintered and cooled in the argon atmosphere to obtain the sodium ferric sulfate / carbon composite material; mixing the sodium ferric sulfate / carbon composite material dispersion liquid with the sodium vanadium fluorophosphate precursor solution, performing hydrothermal reaction, centrifuging, washing and drying to obtain the sodium vanadium fluorophosphate in-situ coated sodium ferric sulfate / carbon composite material. According to the preparation method, a sodium vanadium fluorophosphate coating layer is generated on the surface of sodium ferric sulfate in situ by combining a low-temperature solid-phase method with a hydrothermal method, so that the sodium vanadium fluorophosphate in-situ coated sodium ferric sulfate / carbon composite material is obtained, the electronic conductivity of the composite material is greatly improved, and the sodium ion diffusion rate is promoted by coating of sodium vanadium fluorophosphate; fe2 + is prevented from being oxidized into Fe3 + due to direct contact between the sodium ferric sulfate and air, so that the air stability of the sodium ferric sulfate is improved.

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.

The invention belongs to the technical field of sodium ion battery positive electrode materials, and discloses a preparation method and application of an iron ion doped sodium vanadium phosphate positive electrode material. Modification is carried out by doping iron ions in vanadium sites and taking citric acid as a carbon source for coating, iron nitrate nonahydrate serves as an iron source to participate in the modification process, meanwhile, citric acid is used for carrying out carbon coating on the material, and the citric acid and the doped iron ions synergistically increase the ionic conductivity, so that the problem that the sodium vanadium phosphate material is poor in conductivity is solved. Besides, in the sintering treatment process, the Na3V1.8 Fe0.2 (PO4) 3 / C positive electrode material obtained by doping 0.2 molar weight of iron ions and coating citric acid is always kept in the atmosphere of argon-hydrogen mixed gas, after circulation at the current density of 0.1 C to 20 C, the capacity recovery rate can reach up to 96.1%, and the capacity can still be kept to be 74.1% of the initial capacity at the high rate of 20 C; after 500 cycles under 1C current density, the capacity retention rate is 89.8%, while the capacity retention rate is only 72% after 500 cycles of pure NVP, the rate capability and cycling stability of the material are both improved, and the electrochemical performance of the material is effectively ensured.

The invention provides a preparation method of a carbon-coated manganese-titanium-doped sodium vanadium phosphate positive electrode material, which comprises the following steps: sequentially adding raw materials of a carbon source, a vanadium source, a phosphorus source, a sodium source, a manganese source and a titanium source into deionized water according to a molar ratio, stirring until the solution becomes clear, and carrying out high-temperature calcination through a sol-gel method and a tubular furnace to prepare a Na (4-x) MnV1-XTix (PO4) 3 / C positive electrode material. The target material is of a sea rock similar structure, the surface of the target material is provided with multiple holes, and due to the morphology, the specific surface area of the material is larger, multiple active sites are provided, and the reaction rate is increased. And the surface is coated with carbon, so that the conductivity of the material is greatly improved. Through a double-doping strategy of partially replacing transition metal vanadium sites with titanium and manganese doping, the prepared electrode material has relatively good cycle stability.

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.

The invention discloses a method for preparing lithium vanadium phosphate lithium battery cathode material by in-situ doping of Na<supgt;+< / supgt; in vanadium-containing ore. Using vanadium-containing ore as the initial raw material, through a hydrometallurgical process, a vanadium-containing sodium compound is prepared, and then it is mixed with lithium carbonate and ammonium dihydrogen phosphate and directly calcined. Through the method of in-situ doping in the liquid phase, sodium element is directly doped into the lithium vanadium phosphate material to produce a lithium vanadium phosphate material with good electrochemical performance. The sodium salt in this patent is the original one in the vanadium-containing ore and does not require additional addition; the sodium element is mixed and added in the liquid phase, which is easy to be evenly distributed, thus facilitating the electrochemical uniformity of the lithium vanadium phosphate electrode; using lithium carbonate as the lithium source has a lower cost compared with lithium fluoride. The invention organically combines the traditional metallurgical production process with the production process of the cathode material of new energy lithium-ion batteries, and has many advantages such as simplifying the preparation process of the material, reducing the production cost of the material, and being suitable for industrial production.

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.

The present invention discloses a sodium vanadium phosphate, a preparation method thereof and an application. The preparation method includes: adding an acid or a base to a vanadium-containing waste material or its dispersion liquid, dissolving, adjusting the pH value during dissolution, and then filtering to obtain a solution of the vanadium-containing waste material; adding a valence regulator to the solution of the vanadium-containing waste material to react until the vanadium ions react completely, so that all the vanadium ions in the obtained solution are in the +4 valence state; heating the solution until no obvious bubbles are precipitated; adding an alkali solution to the solution, stirring and reacting to obtain a precursor slurry; adding a phosphate to the precursor slurry to carry out an ion exchange reaction to obtain sodium vanadium phosphate. By the regulation of the valence regulator, the method of the present invention controls the uniformity of the vanadium valence states in different vanadium-containing waste materials, obtains a vanadium source solution with all vanadium in the +4 valence state, and then utilizes the ion exchange technology to realize the recycling of vanadium resources from vanadium-containing waste materials to nano-sodium vanadium phosphate. The prepared nano-sodium vanadium phosphate has good electrochemical properties.

A preparation method of sodium vanadium fluorophosphate as a cathode material for sodium-ion batteries based on spray drying. The present invention relates to a preparation method of a cathode material for sodium-ion batteries, and it aims to solve the problems of poor electronic conductivity and fluorine loss of sodium vanadium fluorophosphate as a cathode material for sodium-ion batteries. The method is as follows: dissolve a carbon source, a phosphorus source, a sodium source, and a vanadium source in water and then perform drying treatment in a spray dryer to obtain a precursor powder; then mix the precursor powder with a fluorine source evenly and calcine for 3 to 6 hours to obtain sodium vanadium fluorophosphate as a cathode material for sodium-ion batteries. It is micron-sized spherical particles with a core-shell structure, the particle size is about 8 μm, and the thickness of the spherical shell is about 200 nm. At a 1C rate, its initial discharge specific capacity is 110.60 mAh / g, and at 10C and 30C rates, its discharge specific capacities are 97.90 mAh / g and 74.70 mAh / g respectively. It can be used in the field of sodium-ion batteries.

The present application provides a positive electrode material and a preparation method thereof, a positive electrode plate and a sodium ion battery. It belongs to the field of sodium ion battery technology, wherein the positive electrode material has a core-shell structure, the core of the core-shell structure is a Prussian blue particle, and the shell of the core-shell structure includes a sodium ferrous vanadium phosphate layer and a carbon layer, wherein the sodium ferrous vanadium phosphate layer is coated on the Prussian blue particle, and the carbon layer is coated on the sodium ferrous vanadium phosphate layer. The positive electrode material of the present application adopts a core-shell structure design of Prussian blue particles, sodium ferrous vanadium phosphate layer and carbon layer from the inside to the outside, and adopts the synergistic effect of low-cost Prussian blue particles and carbon layer with high-cost sodium ferrous vanadium phosphate, while having low cost, and having excellent rate performance, cycle performance and safety.

The invention belongs to the technical field of sodium ion batteries, and particularly relates to a fluorine-nitrogen co-doped carbon-coated sodium vanadium phosphate material as well as a preparation method and application thereof. In order to solve the problems of poor conductivity, low gram volume and the like of a positive electrode material, sodium dihydrogen phosphate, vanadium pentoxide, L-alanine, gelatin, amine fluoride and tetrabutyl titanate are added into an ethanol / water mixed solvent according to a certain proportion, the mixture is transferred into a ball mill for reaction and dried, and uniform powder is obtained. And then, performing high-temperature solid-phase sintering on the powder in rapid Joule thermal equipment to obtain the fluorine-nitrogen co-doped carbon-coated sodium vanadium phosphate material. The method has the advantages of simplicity in operation, easiness in amplification, energy conservation, consumption reduction and the like. Meanwhile, the prepared powder is fluorine-nitrogen co-doped carbon uniformly-coated sodium vanadium phosphate single crystal, and is high in gram volume and excellent in rate capability and cycle performance.

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.