92 results about "Vanadium phosphate" patented technology

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 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.

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 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 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 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 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 preparation method comprises the following steps: S1, taking Cr < 3 + >-doped VO2 powder, a sodium source, a phosphorus source and a carbon source, adding absolute ethyl alcohol, and putting the mixture into a ball mill for ball milling to obtain uniformly mixed slurry; s2, carrying out spray drying on the slurry to obtain a sodium vanadium phosphate precursor; and S3, performing heat treatment on the sodium vanadium phosphate precursor in an atmosphere furnace, cooling, and treating by a jet mill to obtain 2-10 [mu] m powder particles, namely the Cr < 3 + > doped sodium vanadium phosphate positive electrode material. According to the method, the Cr < 3 + >-doped VO2 powder is used as a low-valence vanadium source, the toxicity problem of pentavalent vanadium is avoided, meanwhile, the Cr < 3 + > element obtained through precipitation in the sodium-process vanadium leaching solution can be directly utilized, an external Cr source is not needed, and the uniformity problem easily existing in external doping elements is avoided; through synergistic modification of carbon coating and Cr doping, the electrochemical performance of the sodium vanadium phosphate material can be remarkably improved.

This invention discloses a bimetallic ion-doped sodium vanadium fluorophosphate cathode material and its preparation method, belonging to the technical field of secondary battery cathode materials. The chemical formula of the sodium vanadium fluorophosphate cathode material of this invention is Na. 3‑x Mg x V 2‑y Ti y (PO4)2F3, where 0.01≤x≤0.03, 0.025≤y≤0.075. This invention, through synergistic optimization of the composition and preparation method of sodium vanadium fluorophosphate cathode material, promotes selective titanium doping at vanadium sites and selective magnesium doping at sodium sites, effectively improving the specific capacity, cycle stability, and rate performance of the cathode material. Therefore, sodium-ion batteries assembled using the cathode material of this invention exhibit superior overall performance, demonstrating good capacity retention under both high and low current density conditions, providing an effective way to improve the performance of sodium-ion battery cathode materials.

The invention relates to the field of battery manufacturing, in particular to a carbon-co-oxide-coated sodium vanadium fluorophosphate composite positive electrode material and a preparation method thereof and a sodium ion battery composite positive electrode. The preparation method comprises the steps that a carbon source is added into mixed acid for reaction, then KMnO4 is added for water bath reaction, and the carbon-co-oxide-coated sodium vanadium fluorophosphate composite positive electrode material is obtained; finally, adding a hydrogen peroxide solution for a co-oxidation reaction, and washing and drying after the reaction to obtain a co-oxidation carbon source; wherein the carbon source is a mixture of a one-dimensional carbon source and a two-dimensional carbon source; mixing and grinding the co-oxidation carbon source obtained in the step 1 with a vanadium source, a sodium source, phosphate and a fluorine source to obtain precursor powder, and presintering the precursor powder to obtain a sodium vanadium fluorophosphate intermediate product; and sintering the sodium vanadium fluorophosphate intermediate product at high temperature to obtain the carbon-co-oxide-coated sodium vanadium fluorophosphate composite positive electrode material. The prepared positive electrode material has the advantages of high conductivity, high magnification, high discharge capacity, high power and good cycle stability, and can be used for preparing a sodium ion battery composite positive electrode.

The invention discloses a preparation method of monoclinic sodium vanadium fluorophosphate, which comprises the following steps: taking carbon-coated sodium vanadium phosphate as a crystal nucleus, further mixing the carbon-coated sodium vanadium phosphate with a vanadium fluoride raw material, and carrying out non-aqueous solvent thermal reaction to obtain a reaction product containing the monoclinic sodium vanadium fluorophosphate material, carbon-coated sodium vanadium trifluorophosphate is used as a crystal nucleus and is further mixed with a vanadium phosphate raw material, and a reaction product containing the monoclinic sodium vanadium fluorophosphate material is obtained through a non-aqueous solvent thermal reaction. The synthesis method disclosed by the invention is simple and convenient, and effectively solves the problem of generation of an impurity phase caused by loss of a fluorine element in a solid-phase reaction high-temperature calcination process of traditional monoclinic sodium vanadium fluorophosphate; 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.

The present invention relates to a method for preparing hydrocarbon double acids using a cyclic hydrocarbon oxidation catalyst, wherein adipic acid and dodecanedioic acid may be produced with high yield while solving the problem of environmental pollution, the adipic acid and the dodecanedioic acid being prepared by using an oxidation reaction of a cyclohexane-cyclohexanone mixture and an oxidation reaction of a cyclododecane-cyclododecanone mixture, respectively, in the presence of a vanadium phosphate oxide-based catalyst and / or a cobalt-manganese oxide-based catalyst.

The invention discloses a high-power lithium vanadium phosphate battery cell, an energy storage module and a new energy vehicle. The system is characterized in that a positive electrode material is a first mixed material based on lithium vanadium phosphate; the first mixed material also comprises a binder and a conductive agent; the mass ratio of the lithium vanadium phosphate to the binder to the conductive agent is 80: 8: 12; the negative electrode material is a second mixed material based on graphite or a hard carbon composite material; the second mixed material also comprises a binder and a conductive agent; the mass ratio of the graphite or hard carbon composite material to the binder to the conductive agent is 80: 8: 12; a three-dimensional conductive network based on lithium vanadium phosphate provides a rapid transmission channel for lithium ions, the internal resistance of the negative electrode is further reduced based on a porous structure and excellent conductivity of GrHC, meanwhile, the positive electrode and the negative electrode are in more uniform and compact contact with a diaphragm through a lamination assembly process, rapid migration of the lithium ions is guaranteed through high ionic conductivity of electrolyte, and the lithium ion battery is more stable in performance. And the battery cell has high-power output capability.

This invention relates to the field of sodium-ion battery technology, and in particular to a polyanion-doped sodium vanadium manganese phosphate cathode material, its preparation method, and a sodium-ion battery. The general chemical formula of the polyanion-doped sodium vanadium manganese phosphate cathode material provided by this invention is Na₄VMn(PO₄). 3‑x (SiO4) x Where x is 0.01~0.08; SiO4 4‑ PO4 in the crystal framework is located by isomorphous substitution. 3‑ Site. The polyanion-doped sodium manganese phosphate cathode material of the present invention, SiO4 4‑ Partial PO4 substitution 3‑ The site can directly expand the migration channel size of sodium ions from a crystallographic perspective, effectively reducing the diffusion barrier of sodium ions; the stronger Si-O bond energy enhances the overall stability of the crystal structure. This synergistic effect of expanding channels and strengthening the framework effectively inhibits structural degradation during cycling, especially alleviating the degradation of Mn. 3+ The Jahn-Teller effect.

This invention provides ammonium vanadium oxyphosphate, its preparation method, and a method for preparing vanadium phosphate oxides using it. The preparation method of ammonium vanadium oxyphosphate includes the following steps: adding a reducing agent to a vanadium-containing leachate to reduce the vanadium in the solution to an average valence state of 4.5; then adding a phosphorus source and an ammonium source; reacting to form a precipitate; filtering; and washing to obtain ammonium vanadium oxyphosphate NH4(VOPO4)2. The reaction steps of this invention are simple, the reaction conditions are mild, and the reaction process is easily controlled. This invention also discloses a method for preparing vanadium phosphate oxides using ammonium vanadium oxyphosphate, comprising the following steps: reducing and calcining ammonium vanadium oxyphosphate to prepare vanadium pyrophosphate and / or vanadium phosphate; and then oxidizing and calcining to prepare vanadium oxyphosphate. The vanadium oxyphosphate (VOPO4) prepared by this invention has high crystallinity and a large specific surface area (8-20 μm²). 2 / g), which is beneficial to improving the activity of the catalyst.

The invention relates to the technical field of sodium batteries, in particular to a modified sodium vanadium phosphate positive electrode material and a preparation method and application thereof. The anion-doped sodium vanadium phosphate / carbon positive electrode material is constructed by introducing carbon and various anion-doped elements into the sodium vanadium phosphate positive electrode material, and the surface of the anion-doped sodium vanadium phosphate / carbon positive electrode material is further coated with poly-p-phenylene ethylene, so that a coating layer with a compact and stable structure is formed; the ionic conductivity, electronic conductivity and structural stability of the positive electrode material are enhanced, dissolution of vanadium metal in sodium vanadium phosphate and side reaction between the positive electrode and electrolyte can be inhibited, and the positive electrode material has excellent cycle performance and rate capability.

The invention belongs to the technical field of battery positive electrode materials, and particularly relates to a sodium vanadium pyrophosphate composite material, a preparation method, a sodium ion battery and application, and the preparation method comprises the following steps: crushing a sodium source, a vanadium source, a phosphorus source and a carbon source to obtain first-grade powder, carrying out low-temperature sintering on the first-grade powder in an inert atmosphere to obtain carbon-coated sodium vanadium pyrophosphate, and drying the carbon-coated sodium vanadium pyrophosphate to obtain the carbon-coated sodium vanadium pyrophosphate. The mass ratio of the carbon source to the sodium vanadium pyrophosphate is (0.05-0.1): 1; mixing the carbon-coated sodium vanadium pyrophosphate with the mixed solution, drying to obtain secondary powder, and sintering the secondary powder in an inert atmosphere at 550-800 DEG C to obtain a sodium vanadium pyrophosphate composite material; the lithium ion battery provided by the invention has relatively high first discharge gram capacity and relatively excellent cycle performance and rate capability.

The invention provides a niobium-titanium co-doped lithium vanadium fluorophosphate positive electrode material as well as a preparation method and application thereof. The chemical general formula of the niobium-titanium co-doped lithium vanadium fluorophosphate positive electrode material is LiV < 1-a-b > Nb Ti PO < 4 > F / C, wherein a is the doping molar weight, 0 lt, of the Nb element; a < = 0.05; b is the doping molar weight of the Ti element, 0 lt; b < = 0.05; the content of carbon in the niobium and titanium co-doped lithium vanadium fluorophosphate positive electrode material is 1.5-2.0 wt%. According to the niobium-titanium co-doped lithium vanadium fluorophosphate positive electrode material, niobium (Nb) and titanium (Ti) ions are co-doped, so that the electronic conductivity, the lithium ion diffusion rate and the cycle structure stability of the material are remarkably improved. The niobium-titanium co-doped lithium vanadium fluorophosphate positive electrode material disclosed by the invention has good application prospects and large-scale popularization potential in the field of positive electrode plates of lithium ion batteries.

The application discloses a preparation method of vanadium phosphate nanosheet and application thereof. The preparation method of the vanadium phosphate nanosheet comprises the following steps: A) dissolving a phosphate anion surfactant in a mixed solution of ethanol and water to obtain a solution I; B) mixing a compound containing vanadium ions with the solution I to perform ion adsorption, and through hydrothermal reaction, centrifugation, freezing, drying and annealing treatment, ordered mesoporous vanadium phosphate nanosheet is obtained; the vanadium ions are selected from at least one of divalent, trivalent, tetravalent and pentavalent. When the ordered mesoporous vanadium phosphate nanosheet is used as a positive electrode material of a quasi-solid-state lithium metal battery, the ordered mesoporous vanadium phosphate nanosheet has super-high specific capacity and excellent rate performance, and can realize stable multi-electron reaction. The preparation method has the advantages of low raw material cost, simple process, simple equipment, high efficiency, high repeat efficiency, and important application prospect of the prepared lithium ion battery.

The invention discloses a rare earth monatomic loaded sodium ferrovanadium phosphate positive electrode material, a preparation method and application, and relates to the technical field of sodium ion battery positive electrode materials, rare earth salt is added in the synthesis process, and positive electrode material powder with high product purity and good particle size uniformity is obtained after calcination in a tubular furnace. The synthesis process is simple and convenient to operate, and large-scale synthesis is easy to put into commercial application. Monatomic rare earth elements are respectively loaded on the surface of sodium ferrovanadium phosphate, so that a sodium ion transmission channel is expanded, and the sodium ion diffusion rate and the sodium ion storage performance are further improved. The sodium ion battery prepared from the positive electrode material shows excellent charge-discharge performance, has high charge-discharge specific capacity and good cycle stability under different multiplying powers of 1 C, 2 C, 5 C, 10 C, 20 C, 30 C and 50 C, and provides a new thought and solution for further realization of wide commercialization of sodium ions in the future.

The invention relates to the technical field of positive electrode materials, in particular to a copper-doped carbon nanotube coated sodium vanadium phosphate positive electrode material and a preparation method thereof.The copper-doped carbon nanotube coated sodium vanadium phosphate positive electrode material comprises a sodium vanadium phosphate matrix and a copper-doped carbon nanotube layer coating the surface of the sodium vanadium phosphate matrix; the doping amount of copper in the copper-doped carbon nanotube layer is 1-5% of the mass of the carbon nanotube; the pipe diameter of the copper-doped carbon nanotube is 5 to 20 nm, and the length of the copper-doped carbon nanotube is 100 to 500 nm; the particle size of the sodium vanadium phosphate matrix is 0.5-2 [mu] m; the thickness of the copper-doped carbon nanotube layer is 10 to 50 nm; a large number of experimental studies show that the doping amount of copper in the copper-doped carbon nano tube is controlled to be 1-5% of the mass of the carbon nano tube, in this range, extra carriers can be introduced into crystal lattices of the carbon nano tube through the copper element, the intrinsic resistivity of the carbon nano tube is reduced, the electron conduction efficiency is improved, and it can be avoided that the copper is excessively agglomerated to form an insulating phase; when the copper doping amount is about 3%, the carrier concentration is optimal.

The invention discloses an organic oximic acid sodium supplementing agent and a preparation method and application thereof, the organic sodium supplementing agent has a structure as shown in a general formula I. The organic oximic acid sodium supplementing agent is synthesized for the first time and is used in a sodium ion secondary battery system. The organic sodium supplementing agent is used in a sodium ion total battery system composed of a sodium vanadium phosphate (Na3V2 (PO4) 3) positive electrode and a hard carbon (HC) negative electrode, the battery is completely decomposed and releases sodium ions during first-circle charging, the sodium ions are converted into a product which can be dissolved in an electrolyte, and no gas is generated in the process. The organic oximic acid sodium supplementing agent provided by the invention is simple and convenient in preparation process, high in yield and excellent in stability in air, the theoretical sodium decomposition rate is 90%, the sodium release specific capacity can reach 330 mAh g <-1 > at most, and the actual capacity of a whole battery is improved by supplementing sodium ions consumed by a negative electrode in forming an SEI film or other side reactions; the cycle life and coulombic efficiency of the sodium-ion battery are improved, and the sodium-ion battery electrolyte is an organic sodium-supplementing agent with great potential.

The application provides a light-driven solid-state electrolyte membrane and an integrated flexible light-assisted solid-state sodium metal battery based on the same, and belongs to the technical field of batteries. The battery comprises a light-driven solid-state electrolyte membrane and a photoelectrochemical storage positive electrode. The light-driven solid-state electrolyte membrane comprises polyethylene oxide, a heterojunction filler, a wood fiber soft filler and a sodium salt, wherein the heterojunction filler is a composite material of copper oxide and indium oxide. The photoelectrochemical storage positive electrode comprises an indium selenium oxide film, titanium dioxide and sodium vanadium phosphate. By incorporating a trace amount of heterojunction into the polyethylene oxide electrolyte, the application utilizes the photogenerated electric field generated by the light-driven mechanism to reduce the interface impedance, effectively improves the ionic conductivity and the sodium ion transfer number; and in combination with the energy level matched photoelectrochemical storage positive electrode, the application maximizes the use of photogenerated carriers and enhances the interface compatibility between the electrolyte and the positive electrode; and the battery assembled by the application exhibits excellent cycle stability.

The application relates to a preparation method and application of a rich-pore nanospherical manganese-doped sodium vanadium fluorophosphate positive electrode material. The preparation method is as follows: a vanadium source, hydrogen peroxide and a solvent are uniformly mixed to obtain a mixed solution A; then, a sodium source, a phosphorus source and a fluorine source are added to obtain a mixed solution B; after the mixed solution B is transferred into a reaction kettle and high-temperature reaction, solid powder A is obtained through washing and drying, then, inert gas heating sintering is carried out, and the rich-pore nanospherical fluorophosphate of vanadium is obtained. The material has a rich-pore structure, can effectively shorten the electron and ion transmission path, the multi-pore structure can effectively buffer the volume change of the material in the charging and discharging process, guarantees the structural stability of the material, meanwhile, manganese doping further improves the intrinsic conductivity of the material, stabilizes the structure of the material, and improves the cycle performance of the material. Therefore, the material exhibits excellent long cycle performance as a sodium ion battery positive electrode.

This invention relates to the field of sodium-ion battery technology and discloses a method for preparing a modified sodium vanadium phosphate cathode material, comprising the following steps: Step 1: Add 1-4g of ammonium metavanadate and 0.8-2.6g of oxalic acid to 50-200mL of deionized water, stir and react at 60-120℃ for 20-80min, and after slight cooling, add sodium phosphate; after stirring, add cobalt sulfate heptahydrate, and then dry and grind the solution to obtain precursor powder. Step 2: Calcine the precursor powder in a high-temperature tubular furnace at 600-1200℃ for 8-24h to obtain the modified sodium-ion battery cathode material powder. This invention uses a chemical synthesis method to prepare the precursor and employs an energy-saving calcination process to prepare a cobalt particle-filled sodium vanadium phosphate cathode material for the first time. This process has the advantages of mild reaction conditions, high product purity, good particle size uniformity, and easy control of the proportion of each component, and can be continuously prepared and synthesized in large quantities.