630 results about "Vanadium phosphate" patented technology

The invention discloses a lithium ion battery phosphatic composite cathode material and a preparation method thereof. The composite material is a multinuclear core shell structure composed of a plurality of cores and a housing layer, the cores are lithium iron phosphate particles wrapped by lithium vanadium phosphate and the housing layer is amorphous carbon. Preparation of the lithium iron phosphate particles wrapped by lithium vanadium phosphate comprises the following steps: preparing precursor sol with a sol gel method, adding lithium iron phosphate powder to disperse uniformly, carrying out spray drying on the above mixture, calcining the above resultant in inert gas, and followed by cooling and grinding to obtain the lithium iron phosphate particles wrapped by lithium vanadium phosphate. Preparation of the composite cathode material comprises the following steps: dissolving a carbon source compound into deionized water, adding core materials, dispersing the above resultant uniformly, carrying out second spray drying, calcining the above resultant in inert gas, and followed by cooling to obtain the composite cathode material. The composite material prepared in the invention has good electronic conduction performance, good ionic conduction performance and excellent electrochemistry performance. Because of existence of lithium vanadium phosphate, energetic density of a material is raised. Because of the multinuclear core shell structure like nano/micro structures, the composite material has good processing performance, and tap density of the material is greatly raised.

A preparation method of a carbon coated vanadium sodium phosphate positive electrode material comprises the steps: with glucose as a reducing agent and a carbon source and water as a dispersant, carrying out ball milling of NH4VO3, NaH2PO4.2H2O and glucose in water, carrying out spray drying, calcining, and thus obtaining the carbon coated vanadium sodium phosphate positive electrode material. The method has the advantages of low synthesis temperature, simple steps, easily obtained raw materials, and advantageous industrialization; the obtained carbon coated vanadium sodium phosphate positive electrode material has a structure with uniform primary particles, has the particle size of 100-200 nm, and has the characteristics of short sodium ion diffusion distance, fast transmission speed, high specific surface area, high electrical conductivity and fast ion transmission and the like. The obtained carbon coated vanadium sodium phosphate positive electrode material is assembled into a battery; in a voltage scope of 2.0-3.75 V and under 1 C multiplying power, the highest first charge and discharge capacity per gram can reach 93.5 mAh*g<-1>, the capacity retention rate can be up to 97.7% after cycling for 50 circles with the 1C multiplying power, and excellent electrochemical performance is showed.

The invention discloses material with mixture of ions with sodium vanadium phosphate cathode material coated by carbon and a preparing method thereof, characterized in that the general formula of sodium vanadium phosphate cathode material is Na3V2-xMx(PO4-y)3Y3y/C, wherein 0<x<=0.2, 0><y<=0.05, M is Al, Fe, Cr, Ni, Co, Mg, Zn, La, Cu, Mn, Ti, Mo, Sn, Sr, Nb, Ce or Y, Y is For Cl. Through the carbon coating and the doping modification with ions for sodium vanadium phosphate cathode material, the electron conductivity of the material is improved and the electron-chemical property of material can be improved obviously.

The present invention relates to the technical field of battery materials, and in particular relates to a preparation method of a three-dimensional porous vanadium phosphate sodium / carbon anode material. The method comprises the following steps: (1), dissolving a weighed vanadium source in a mixed solvent of deionized water and hydrogen peroxide, adding a sodium source, a phosphorus source and an organic complex until complete dissolution, pouring the reaction products in a reaction kettle for a hydrothermal reaction, wherein the molar ratio of Na:V:P is 3:2:3; and (2), after the hydrothermal reaction, drying the obtained three-dimensional precursor and then calcining in a gas mixture of argon and hydrogen (5%) at the temperature of 750 DEG C for 8h. The vanadium phosphate sodium / carbon composite material prepared by the invention has carbon coating to improve the electronic conductivity; and the three-dimensional structure porous structure improves the transmission efficiency of sodium ions between the electrode and the electrolyte, and plays a buffer role for deformation of sodium ions in the deintercalation process, and eventually greatly improves the cycle performance and rate performance of the material.

The invention discloses a lithium vanadium phosphate/graphene composite material and a preparation method thereof. The lithium vanadium phosphate/graphene composite material consists of lithium vanadium phosphate and graphene or graphene and other amorphous carbon. The preparation method comprises the following steps: mixing oxidized graphite and deionized water, performing ultrasonic treatment, or further adding a reducing agent and then performing ultrasonic treatment; and adding a material or colloidal sol precursor for synthesizing lithium vanadium phosphate, water bathing at 60-90 DEG C while stirring, continuing ultrasonic treatment, drying and grinding, performing heat treatment in the presence of inert or reducing gas, and naturally cooling to room temperature to obtain the lithium vanadium phosphate/graphene composite material. The composite material prepared by using the method disclosed by the invention is used as the lithium ion battery anode material, the specific capacity of the composite material is up to 115 mAh.g<-1> in case of charging/discharging at 10C multiplying factor, and the composite material has nearly no attenuation after 500 cycles. The method has simple synthesis process and good repetitiveness, and provides an anode material with high capacity and long service life for the application of high multiplying factor lithium ion batteries.

The invention relates to a preparation method of a lithium vanadium phosphate (Li3V2(PO4)3)/graphene composite material for a positive electrode of a lithium ion battery. The method comprises the steps that firstly, a mixed precursor solution is prepared; pretreatment of spray drying is conducted and a precursor is obtained; and then the lithium vanadium phosphate positive electrode material of the lithium ion battery is prepared through a calcination reaction under an inert atmosphere condition. Compared with the prior art, the preparation method has the advantages that the combination mode of the Li3V2(PO4)3 and the graphene, the contents of carbon and the graphene, and the particle size of the material are effectively controlled, thereby improving the stability and the electrical conductive performance of the material.

The invention discloses a lithium vanadium phosphate anode material used in a lithium battery and a preparation method thereof, and solves the technical problem that can improve the electrical conductivity and high-rate discharge property of the anode material. The inventive anode material comprises a matrix coated outside with a conductive nano-composite material with a particle size of 5-50 Mu m and a specific surface area of 5-25m<2>/g. The inventive anode material is prepared by the following steps: wet-method superfine ball mill, liquid-phase mixture reaction, spray drying, pretreatment, calcinations treatment, coating with conductive composite material, and fusion. Compared with the prior art, the invention can synthesize lithium vanadium phosphate anode material by the secondary molding liquid phase method of nanoparticles, and the product purity is high, the particle agglomeration is efficiently prevented. The synthetic lithium vanadium phosphate anode material has a discharge voltage about 4V, three discharge voltage platform zones, higher charge/discharge capacity, excellent rate discharge capability and loop stability, and low cost; and is suitable for the industrial production.

The present invention relates to a method for preparing a lithium vanadium phosphate material comprising mixing water, lithium dihydrogen phosphate, V₂O₃ and a source of carbon to produce a first slurry; wet blending the first slurry; spray drying the wet blended slurry to form a precursor composition; milling the precursor composition to obtain a milled precursor composition; compacting the milled precursor to obtain a compacted precursor; pre-baking the compacted precursor composition to obtain a precursor composition with low moisture content; and calcining the precursor composition with low moisture content at a time and temperature sufficient to produce a lithium vanadium phosphate. The lithium vanadium phosphate so produced can optionally be further milled to obtain the desired particle size. The electrochemically active lithium vanadium phosphate so produced is useful in making electrodes and batteries and more specifically is useful in producing cathode materials for electrochemical cells.

The invention discloses a lithium battery electrode material, comprising a plurality of uniformly distributed lithium iron phosphate/lithium vanadium phosphate composite particles. The material is characterized in that each lithium iron phosphate/lithium vanadium phosphate composite particle comprises a lithium vanadium phosphate particle and a lithium iron phosphate particle layer uniformly coated on the surface of the lithium vanadium phosphate particle, wherein, the lithium iron phosphate particle layer comprises a plurality of lithium iron phosphate particles.

The invention relates to an oxo-vanadium phosphate catalyst, and a preparation method and application thereof. The catalyst is prepared through the following steps: preparing a precursor by performing ionothermal synthesis on vanadium pentoxide or metavanadate and phosphate or biphosphate used as raw materials in ionic liquid or eutectic mixture solvent at 120-180 DEG C under normal pressure; and then roasting. The synthesis method is operated under normal pressure, is safe and convenient, and has low requirements for equipment. The catalyst prepared through the method has a special spherical or claviform shape, has high specific surface area and can be used for cyclohexanol oxidation reaction.

The invention belongs to the technical field of electrode materials and relates to sodium vanadium fluorophosphate as well as a low-temperature environment-friendly preparation method and use thereof. The preparation method comprises the steps of preparing a mixed water solution of a sodium source, a vanadium source, a phosphorus source and a fluorine source, reacting by virtue of the mixed water solution at 20-180 DEG C to obtain sodium vanadium fluorophosphate, wherein the vanadium source is a trivalent vanadium source and/or a tetravalent vanadium source; the chemical constitution of sodium vanadium fluorophosphate is Na3(VOxPO4)2F3-2x, and x is more than or equal to 0 and less than or equal to 1. According to the low-temperature environment-friendly preparation method, the mixed water solution of the sodium source, thephosphorus source, the fluorine source and the trivalent vanadium source and/or a tetravalent vanadium source can generate spontaneous reaction at 20-35 DEG C, the reaction can be accelerated at a temperature high than 35 DEG C and lower than 180 DEG C, and well-crystallized sodium vanadium fluorophosphate can be obtained. Sodium vanadium fluorophosphate can be used as an anode to be assembled into a battery, the specific discharge capacity is not lower than 100mAh/g, and the cycling stability is good.

The present invention provides for the two step preparation of lithium vanadium phosphate by pre-treatment of a mixture of precursor materials via high pressure at relatively low temperatures in water (hydrothermal pretreatment) and then calcining such hydrothermally pretreated precursors at relatively high temperatures for a period of time sufficient to produce lithium vanadium phosphate. The lithium vanadium phosphate so produced finds use in producing electrodes for electrochemical cells.

The invention discloses a doped and modified sodium vanadium fluorophosphate cathode material and a preparation method thereof. According to the cathode material, the problems that an existing sodiumvanadium fluorophosphate cathode material is poor in rate capability and instable in cycle performance are solved. The nominal molecular formula of the cathode material is Na3V2-xCax(PO4)2F3, whereinx is more than 0 and less than or equal to 0.2. The preparation method comprises the following steps: uniformly dissolving a sodium source, a calcium source, a vanadium source, phosphate and a carbonsource into a deionized water medium in a stoichiometric ratio so as to obtain a mixed solution, and drying, so as to obtain a sodium vanadium fluorophosphate precursor, wherein the carbon source is used for controlling a V valence state in a compound; and carrying out thermal treatment on the precursor at 300-400 DEG C in an inert atmosphere, and sintering at 600-700 DEG C, so as to obtain the doped and modified sodium vanadium fluorophosphate cathode material. The material has relatively high ionic conductivity and electronic conductivity and therefore has excellent rate capability; the cycling stability of the material in electrochemical charging and discharging processes are enhanced; and the preparation craft process is simple.

The present invention relates to a method for preparing a lithium vanadium phosphate material comprising forming a aqueous slurry (in which some of the components are at least partially dissolved) comprising a polymeric material, an acidic phosphate anion source, a lithium compound, V₂O₅ and a source of carbon; wet blending said slurry, spray drying said slurry to form a precursor composition; and heating said precursor composition to produce a lithium vanadium phosphate. In one embodiment the present invention relates to a method for preparing a lithium vanadium phosphate which comprises reacting vanadium pentoxide (V₂O₅) with phosphoric acid (H₃PO₄) to form a partially dissolved slurry; then mixing with an aqueous solution containing lithium hydroxide; adding a polymeric material and a source of carbon to form a slurry; wet blending said slurry; spray drying said slurry to form a precursor composition; and heating said precursor composition for a time and at a temperature sufficient to produce a lithium vanadium phosphate compound. In an alternative embodiment the present invention relates to a method for preparing a lithium vanadium phosphate which comprises preparing an aqueous solution of lithium hydroxide; partially dissolving vanadium pentoxide in said aqueous solution; adding phosphoric acid to the aqueous solution; adding a polymeric material and a source of carbon to the solution containing vanadium pentoxide to form a slurry; spray drying said slurry to form a precursor composition; and heating said precursor composition for a time and at a temperature sufficient to form a lithium vanadium phosphate. The electrochemically active lithium vanadium phosphate so produced is useful in making electrodes and batteries.

The invention provides a carbon-coated lithium vanadium fluorophosphate lithium ion battery positive electrode material and a preparation method thereof; the preparation method of the carbon-coated lithium vanadium fluorophosphate lithium ion battery positive electrode material comprises the following steps that a vanadium source, a phosphorus source and a carbon source are added into water to form a solution, and continuous stirring is carried out until a stable viscous solution is formed or rapid solidifying is performed; drying is performed on the viscous solution or the solid obtained in the last step, and heat treatment is performed in a non-oxidizing atmosphere, and then crushing and grinding are carried out to obtain the black carbon coated vanadium phosphate powder; mixing is carried out on the carbon-coated vanadium phosphate powder, lithium fluoride and a fluorine source to obtain precursor powder, and under the non-oxidizing atmosphere, sintering is carried out at 550-750 DEG C for 0.5-10h to obtain the carbon-coated lithium vanadium fluorophosphate material. The method is simple in process route, easy to operate, low in generating cost and capable of realizing large-scale production. The carbon-coated lithium vanadium fluorophosphate lithium ion battery positive electrode material prepared by the method is high in phase purity, uniform in particle sizes and excellent in electrochemical performance.

Disclosed are a porous spherical carbon-coated sodium vanadium phosphate composite positive electrode material and a preparation method thereof. The composite positive electrode material is prepared by the steps of (1) dissolving a vanadium source compound and a reducing agent into water, performing heating and then adding a phosphorus source compound and a sodium source compound to obtain a mixedsolution; (2) adding an organic solvent, wherein the polarity of the organic solvent is greater than that of water, and putting into a sealed container to be subjected to a heating reaction, and next, performing cooling, centrifuging, washing, depositing and drying to obtain precursor powder; and (3) performing mixing with glucose, and performing sintering and cooling on the mixture in protectiveatmosphere. The positive electrode material is spherical and has the primary granular diameter of 50-200nm; when the composite positive electrode material is assembled into a battery, the initial discharge capacity per gram at 0.2C and 10C within a voltage range of 2.0-3.8V can reach 110 mAh.g<-1> and 95 mAh.g<-1> respectively; the capacity retention rate can reach 99.47% at 10C rate after 100 cycles; and the method is simple and low in reaction temperature.

A vanadium sodium phosphate positive electrode material, a sodium ion battery, and a preparation method therefor and application thereof. The preparation method of the vanadium sodium phosphate positive electrode material comprises the following steps: (1) reacting an aqueous solution containing a vanadium source with a phosphorus source, a reducing agent, a sodium source, and a carbon source, the reaction comprising first performing a reaction of an aqueous solution of the vanadium source and the phosphorus source, and then perform a reaction with the reducing agent, or first performing a reaction of the aqueous solution of the vanadium source with the reducing agent and then performing a reaction with the phosphorus source; (2) drying and calcining the reaction liquid obtained in step (1). The vanadium sodium phosphate positive electrode material has a high dispersibility, and has stable circulation performance when used in a battery.

The invention provides a cathode material for a sodium-ion battery, a preparation method of the cathode material for the sodium-ion battery and the sodium-ion battery. The method that a metal oxide catalyzes carbon sources to grow graphene in situ provided by the invention realizes the free conversions of the carbon sources, thereby being beneficial to industrial mass production. Furthermore, a certain amount of organic carbon sources are added in the synthesis process of Na3V2 (PO4)3(Sodium Vanadium Phosphate), and catalyzed to generate graphene under the effect of metal oxide, namely vanadium oxide at low temperature, and the graphene is uniformly coated on the surfaces of vanadium phosphate sodium particles to form a uniform carbon network layer, so that the conductivities of the material ions and electrons are enhanced to improve electrochemical performance of the material.