45 results about "Solid phase reactions" patented technology

This invention discloses a high-entropy transition metal nitride ceramic material and its preparation method. The preparation method includes the following steps: mixing n kinds of transition metal nitride powders and m kinds of transition metal powders, vacuum drying to obtain a precursor; placing the precursor in a mold and performing pre-pressing treatment to obtain a pre-pressed sample; sintering the pre-pressed sample in a sealed environment at a temperature of 500–3500℃ and a pressure of 2–28 GPa to obtain the high-entropy transition metal nitride ceramic material; wherein n≥1, m≥0, and the total number of transition metal elements in the precursor is four or more. This invention improves the stability of the precursor and reduces the size and distance of particles within the precursor through two pressure treatments, achieving for the first time the synthesis of high-density, high-purity high-entropy transition metal nitride ceramic materials via solid-state reaction.

The application relates to a dual-phase high-entropy ceramic material for high-temperature thermal barrier coatings and a preparation method thereof, in particular to a dual-phase high-entropy ceramic (La 0.2 Nd 0.2 Gd 0.2 Y 0.2 Ho 0.2 )2Zr2O7 with low thermal conductivity and high thermal expansion coefficient, which is mainly used for thermal isolation, thermal barrier coatings and other applications in high-temperature environments. The application is prepared by adopting a solid-phase reaction sintering process through accurate design of the combination of rare earth elements, forms a stable dual-phase structure, effectively inhibits grain growth through grain boundary pinning, and thus maintains a nanoscale grain structure. Meanwhile, the material can efficiently block heat transfer at high temperatures through optimization of phase proportion, and the thermal expansion characteristics are matched with a metal base layer, effectively avoiding the falling risk caused by the difference in thermal expansion of the two, and thus greatly improving the service life and reliability of the material in a high-temperature environment. The high-entropy ceramic material of the application can be widely applied to fields with high demand for high-temperature thermal isolation in aerospace, aviation, automobile industry and the like, is especially suitable for thermal barrier coatings, high-temperature thermal insulation materials and other high-temperature thermal insulation applications, and has important engineering application value.

The application discloses a preparation method and system of sodium difluorophosphate. The preparation method of sodium difluorophosphate comprises the following steps: S100, in a water-free or low-water environment, a solid-phase reaction is generated between diphosphorus pentoxide and ammonium fluoride to obtain an ammonium difluorophosphate intermediate, and volatile substances generated in the reaction process are removed and recovered; S200, in a water-free organic solvent, the ammonium difluorophosphate intermediate obtained in the step S100 is reacted with a sodium salt to obtain sodium difluorophosphate. The preparation method of sodium difluorophosphate provided by the application uses diphosphorus pentoxide and ammonium fluoride as reaction raw materials to obtain an ammonium difluorophosphate intermediate, and then reacts to obtain sodium difluorophosphate. The obtained sodium difluorophosphate has high purity and few impurities. The preparation method of sodium difluorophosphate has the advantages of cheap and easily obtained raw materials, stable chemical properties, few by-products generated in the reaction, and easy recovery, and is a green and safe preparation method of sodium difluorophosphate.

The application provides a high-nickel ternary single-crystal positive electrode material and a preparation method, a positive electrode sheet and a lithium ion battery. The preparation method of the high-nickel ternary single-crystal positive electrode material comprises the following steps: providing a precursor, the porosity of the precursor being 30%-50%; mixing the precursor with a lithium source, and performing nitrogenization treatment under an ammonia atmosphere to prepare a nitrogenization treatment product; performing pre-oxidation treatment on the nitrogenization treatment product under an oxygen atmosphere to prepare a pre-oxidation treatment product; performing sintering treatment on the pre-oxidation treatment product under an oxygen atmosphere to prepare the high-nickel ternary single-crystal positive electrode material; and the temperature of the sintering treatment being 700 DEG C-900 DEG C. The preparation method of the high-nickel ternary single-crystal positive electrode material provided by the application reconstructs the solid-phase reaction path of the high-nickel material, suppresses the Li + / Ni 2+ mixing arrangement while realizing controllable preparation of single-crystal particles at a low temperature, so that the high-nickel ternary positive electrode material with high capacity retention rate and excellent cycle stability is obtained.

The application discloses a yttria-corundum-mullite composite material, which comprises the following chemical components in percentage by mass: mullite 34.3%-34.475%, corundum 63.7%-64.025% and yttria 1.5%-2%; the apparent porosity of the composite material is 17.13%-18.03%; the composite material comprises corundum phase, mullite phase and yttrium aluminum garnet phase, and the yttrium aluminum garnet phase is generated by solid phase reaction of yttria and corundum in a high-temperature sintering process; by adding 1.5%-2wt% yttria as a modifier, the bending strength of the composite material is up to 58.53MPa, and the strength is improved by 131.50% compared with that of the corundum-mullite material without adding yttria; the apparent porosity is reduced to 17.13%-18.03%, the bulk density is optimized to 2.4333g / cm3, and the densification degree is greatly improved.

This invention discloses a method and system for monitoring low-temperature solid-state reactions in gas-solid two-phase flow based on in-situ Raman spectroscopy, relating to the application of fiber optic sensing in solid-state reactions. The method includes: S1, designing the thickness t of the observation window glass on the top cover of the reaction chamber based on the volume of the gas-solid two-phase flow low-temperature solid-state reaction device; S2, installing the laser Raman probe in the in-situ Raman spectroscopy detection module at the location of the observation window glass; S3, adjusting the operating parameters of the gas-solid two-phase flow low-temperature solid-state reaction device and introducing high-pressure nitrogen gas into the reaction chamber; S4, starting the in-situ Raman spectroscopy detection module, setting the spectral acquisition parameters, and acquiring the Raman spectral characteristics of the substances within the reaction chamber through the laser Raman probe. Based on the acquired Raman spectral data, this invention can be used to analyze the solid-state reaction mechanism and reaction kinetics, and provide real-time feedback information for the optimized design of low-temperature solid-state reaction conditions in gas-solid two-phase flow.

The application provides a production process of a sodium ion battery electrolyte. The production process comprises the following steps: a) dissolving phosphorus pentachloride in a carbonate solvent under a protective atmosphere, then adding ammonium fluoride and performing a solid-phase reaction by heating; then, removing insoluble substances through solid-liquid separation to obtain solution A; b) dispersing a sodium source in a solvent to obtain solution B; c) adding solution B into solution A under a protective atmosphere to perform a reaction, then removing impurities through solid-liquid separation and removing the solvent introduced in step b) to obtain a crude sodium ion battery electrolyte; d) mixing the sodium ion battery electrolyte with an organic solvent to obtain a sodium ion battery electrolyte; the organic solvent is different from the carbonate solvent used in step a); wherein, steps a) and b) are not limited in sequence. The production process can directly prepare a sodium ion battery electrolyte with sodium hexafluorophosphate as a sodium salt, the process is simple and environmentally friendly, and the yield and purity of sodium hexafluorophosphate are relatively high.

This invention discloses a fluorescence emission-independent excitation carbon quantum dots and its preparation method. The method includes: Step 1, mixing o-phenylenediamine and boric acid at a molar ratio of 4 mmol:(1.2~4 mmol), grinding the mixture, transferring it to a square ceramic boat, and placing it in an oven. Under air atmosphere, the temperature is increased from room temperature to 100~135℃ at a heating rate of 5℃ / min, and the solid-phase reaction is carried out for 4~6 h. The mixture is then naturally cooled to room temperature to obtain a brownish-red solid; Step 2, dissolving the brownish-red solid in deionized water and sonicating it to obtain a yellowish-brown liquid; Step 3, filtering the yellowish-brown liquid to obtain a pure carbon quantum dot aqueous solution; Step 4, freeze-drying the carbon quantum dot aqueous solution to obtain carbon quantum dot powder. This invention simplifies the process flow, reduces energy consumption and post-processing complexity, and provides controllable reaction process. The prepared carbon quantum dots exhibit fluorescence emission-independent characteristics and long-wavelength orange fluorescence.

This invention relates to the field of relaxor ferroelectric ceramic dielectric energy storage materials, specifically to a sodium bismuth titanate-based relaxor ferroelectric ceramic and its preparation method, wherein the chemical composition of the sodium bismuth titanate-based relaxor ferroelectric ceramic is (1-x)BNLT. ‑x BAN, of which BNLT is 0.9Bi 0.5 Na 0.5 TiO3-0.1Bi 0.5 Li 0.5 TiO3, BAN is BaAl 0.5 Nb 0.5 The value of O3 and x ranges from 0.06 to 0.18. When x = 0.15, the ceramic exhibits excellent performance with a recoverable energy storage density (Wrec) of not less than 14.0 J / cm³ and an energy storage efficiency (η) of not less than 84% under an electric field of 775 kV / cm. This invention employs a solid-state reaction sintering process, which is simple to prepare and low in cost, making it suitable for high-performance energy storage capacitors in pulsed power systems.

The application discloses a group IIIA-VIA-VIA ternary compound semiconductor crystal and a preparation method and application thereof, and belongs to the technical field of semiconductor materials. x B 1‑x C3 or A x B 1‑x C, wherein A and B are selected from two of In, Sb, Bi, Ge and Sn, C is selected from S, Se and Te, and 0 The application provides a preparation method combining a solid phase reaction and a chemical gas phase transport, which comprises nanometerization pretreatment of raw materials, packaging according to an optimized molar ratio in an inert atmosphere, low-temperature solid phase reaction of a swing furnace, double-temperature-zone chemical gas phase transport growth, and post-processing and device integration. The method realizes controllable preparation of various group IIIA-VIA-VIA ternary compound high-quality single crystals, and solves the problem that high-quality single crystals are difficult to obtain by using a traditional method. The obtained crystal has obvious in-plane optical anisotropy, and an optoelectronic device prepared based on the crystal exhibits excellent polarized light detection performance in a wide spectral range at room temperature, and is suitable for the fields of encrypted communication, optoelectronic sensing and integrated optoelectronic devices.

This invention relates to the field of battery material preparation technology, and discloses a method and apparatus for preparing lithium battery materials. The method includes: conveying precursor powder and grinding beads into the interior of a kiln to form an infeed mixture; introducing a protective gas into the kiln to create a counter-current atmosphere; rotating the kiln and using a spiral guide rail to move the infeed mixture, causing the precursor powder to react and generate lithium battery material powder, which, together with the grinding beads, forms a sintering mixture; the sintering mixture enters a grinding bead separation system, the lithium battery material powder is discharged through a screen, and the grinding beads are returned to the grinding bead storage chamber via a grinding bead recycling system. This invention, by introducing grinding beads into the kiln, breaks up the agglomeration of the precursor powder during the solid-phase reaction stage, avoiding uneven sintering caused by localized temperature buildup; the counter-current atmosphere promotes the discharge of reaction gas; and the closed-loop recycling of the grinding beads ensures continuous operation of the preparation process.

The application discloses a conductive ceramic additive / solid electrolyte composite material and a preparation method thereof, and belongs to the technical field of solid electrolyte materials. The application solves the problem of low room temperature ionic conductivity of existing solid electrolyte materials. The material is of a chemical formula xLaNbO4-yNZSP / zLATP / alphaLLT / beta8YSZ or beta3YSZ / gammaSrTiO3, 0.5mol%<=x<=3mol%, and y, z, alpha, beta and gamma have only one of them being not 0; NZSP is Na 3.4 Zr2Si 2.4 P 0.6 O 12 , LATP is Li 1.5 Al 0.5 Ti 1.5 P3O 12 , LLT is Li 0.34 La 0.56 TiO3, and YSZ is 3YSZ or 8YSZ. The method is a solution assisted solid phase reaction method or a sol-gel esterification method. The process is simple, the cost is low, and the obtained solid electrolyte material has high ionic conductivity at room temperature.

The present application relates to the field of chemical heat generating material, in particular to a built-in self-heating food heating agent and a preparation method thereof.The built-in self-heating food heating agent provided by the present application comprises a solid phase reaction agent, the solid phase reaction agent comprises 65-85 parts of magnesium powder, 10-30 parts of iron powder and 2-10 parts of modified auxiliary agent by mass fraction; a liquid phase reaction agent, the liquid phase reaction agent comprises 200-300 parts of a salt aqueous solution with a concentration of 5%-20% w / w by mass fraction.By separating the hygroscopic electrolyte salt which is easy to cause reaction from the solid phase reaction agent completely, the solution is separately packaged.The solid phase reaction agent is only a mixture of magnesium powder, iron powder and modified auxiliary agent, and is not sensitive to air humidity without contacting the salt solution, which fundamentally eliminates the internal micro-battery reaction caused by salt moisture absorption, completely eliminates the safety hazards such as spontaneous heating, bag swelling and explosion during storage and transportation, and significantly prolongs the shelf life of the product.

The application discloses an ultralow dielectric loss aluminate microwave dielectric material and a preparation method thereof. A Zn 3‑x B x AlO7, wherein A =Sr, Ba, B =Co, Ni, 0<=x<=0.08. x Its preparation process is as follows: porcelain powder solid phase reaction method synthesis, ball milling, pressing forming, sintering into porcelain. The main crystal phase of the ultralow dielectric loss aluminate microwave dielectric material is a single-phase '114' configuration compound, has the advantages of low raw material cost, low dielectric constant (10-15), high Q f Value (102000-255000 GHz), simple preparation process, good reproducibility and the like, and can solve the time delay problem of microwave signals in high-frequency communication, improve the stability of microwave signal transmission, and is very suitable for manufacturing resonators, filters, dielectric substrates and dielectric antennas and the like.

This invention discloses a high-pressure compaction spherical lithium iron phosphate material, its preparation method, and its applications. In the initial ball milling process, a mixed solution of anhydrous ethanol and deionized water is selected as the dispersion solvent. The presence of deionized water facilitates the rapid dispersion of the carbon source and promotes the uniform coating of lithium iron phosphate with carbon materials, thereby improving the conductivity of the lithium iron phosphate material. Ammonium bicarbonate and polyvinyl alcohol are also added as dispersants. These dispersants prevent particle aggregation and reduce the particle size after the first ball milling, allowing for more complete solid-phase reactions. Furthermore, the dispersants reduce the nucleation rate during high-temperature calcination, resulting in a more uniform morphology of the prepared lithium iron phosphate. The gas generated during high-temperature calcination effectively prevents particle aggregation through gas ejection. In addition, the generated gas also protects the lithium iron phosphate from oxidation. When applied to lithium-ion batteries, this material exhibits high discharge specific capacity and good cycle performance.

This invention provides a method and application for synthesizing ceramic precursors using microwave field enhancement. The method includes: uniformly and densely mixing metal oxide powder and microwave absorbing medium powder to obtain a composite material; subjecting the composite material to microwave irradiation under a CO2 atmosphere at a temperature range of 300°C to 500°C; and cooling after the microwave irradiation reaction to obtain the ceramic precursor. This method is the first to propose and realize a novel approach for synthesizing ceramic precursors by directly conducting a large-scale solid-phase reaction between flowing CO2 and solid metal oxides under microwave field assistance and low-temperature (300°C to 500°C) conditions. Utilizing the unique effect of the microwave field, the method precisely activates oxygen or defect sites in the metal oxide lattice, significantly improving the solid-gas reaction rate and efficiency; and achieving one-step synthesis of ceramic precursors with specific morphology, high specific surface area, and uniform composition.

The application relates to the field of biological fertilizers, and particularly discloses a biomass-based slow-release biological fertilizer and a preparation method thereof. The biomass-based slow-release biological fertilizer comprises raw materials: a chemical fertilizer component, a functional fiber matrix, an inorganic cementing material, a composite synergist, a microbial agent and a chelating agent. The inorganic cementing material comprises solid-phase reactants and liquid-phase reactants in a mass ratio of 1-3:1. The solid-phase reactants and the liquid-phase reactants are used as the inorganic cementing material, a low-temperature chemical self-curing system is adopted, a firm crystal network is generated through in-situ reaction of the inorganic cementing material under mild conditions of 15-40 DEG C, the fertilizer particles are endowed with a mechanical strength of 8N or more, and powdering and transportation damage are effectively avoided. Meanwhile, the whole preparation process is low-temperature, and the activity of the microbial agent is ensured from being damaged, and the survival rate of the microbial agent is as high as 89% or more.

This invention discloses an adaptive upscaling method for multi-field coupled fracture evolution in thermal flow solidification, relating to the fields of unconventional oil and gas reservoir development and reservoir numerical simulation. The method includes: establishing fine-scale and coarse-scale models; establishing a simplified model and running it to obtain the temperature field; running the full physical coarse-scale model and correcting the predicted fine-scale temperature; iteratively calculating the fine-scale reaction rate and upscaling; adaptive dynamic correction of the reaction frequency factor of the coarse-scale model; coarse-scale multi-field coupled solution and thermally induced fracture identification; thermally induced fracture merging and evolution and updating of multi-field physical parameters; time stepping and simulation termination. The beneficial effects of this invention are that, while ensuring the accuracy of fine-scale calculations, it can significantly accelerate the simulation of multi-field coupled fracture dynamic evolution, and can be widely applied to field-scale numerical simulations of various underground energy engineering projects with solid-phase reactions as the main controlling mechanism, such as in-situ conversion of oil shale, underground coal gasification, and in-situ upgrading of oil sands.

The application belongs to the technical field of nanometer materials, and particularly relates to a laser induction heating combined preparation method for high-melting-point superfine nanoparticles. The high-melting-point superfine nanoparticles are titanium, tantalum, niobium metal materials or metal oxides with a particle size of 10 nm to 20 nm. The laser induction heating combined preparation method is to ablate a metal material block subjected to pre-treatment by induction heating by using a laser under an argon or air atmosphere, and to initiate a high-temperature gas-solid phase reaction. The high-melting-point metal superfine nanoparticles are collected by blowing in argon, the metal oxide superfine nanoparticles are collected by blowing in air, and then the collected nanoparticles are washed, frozen and dried to obtain the nanoparticles. The application solves the problems of existing fine-particle powder, such as difficult preparation, low powder yield and high content of other impurities. The application has the advantages of simple preparation operation, good biocompatibility, green and environment-friendly and non-toxic materials, and is suitable for the fields of biomedicine and the like.

This invention provides a lithium manganese nickel oxide cathode material and its preparation method. The preparation method involves a two-stage calcination process: low-temperature pre-calcination and high-temperature calcination in an oxidizing atmosphere. The solid-phase reaction temperature and oxidizing atmosphere are controlled to ensure that manganese ions on the material surface are fully oxidized to Mn. 4+ In the preparation process of lithium manganese nickel oxide cathode material, a Li2MnO3 nano-coating layer coherent with the bulk phase is formed in situ, transforming harmful Li2MnO3 impurities into a second phase that enhances capacity. The prepared lithium manganese nickel oxide cathode material has a higher capacity. The preparation method of lithium manganese nickel oxide cathode material provided in this application is simple and does not require additional coating processes. It can realize the in-situ Li2MnO3 coating structure and effectively improve the discharge capacity of lithium manganese nickel oxide cathode material.

This invention relates to the chemical industry, specifically to a transesterification reaction system and a method for co-producing battery-grade methyl ethyl carbonate and diethyl carbonate. The system includes: a raw material vaporization unit, an adiabatic reaction unit, and an alcohol-ester separation unit connected in series along the material flow direction; and a purification unit, the inlet of which is connected to the ester-containing stream outlet of the alcohol-ester separation unit via a pipeline. The technical solution of this invention, by employing a gas-solid phase reaction within an adiabatic reactor, improves the reaction rate and reactor production capacity, reduces energy consumption, extends catalyst lifespan, simplifies the process flow, and reduces production costs while ensuring product purity.

The present application relates to a kind of low dielectric loss and low temperature coefficient microwave dielectric ceramic and its preparation method, the preparation method includes the following steps: after mixing zinc lanthanum titanate, strontium source and auxiliary raw material, sequentially forming and sintering, the low dielectric loss and low temperature coefficient microwave dielectric ceramic is prepared;The auxiliary raw material includes any one or combination of at least two of calcium carbonate, manganese dioxide or barium carbonate.The present application selects zinc lanthanum titanate and strontium titanate with good microwave dielectric properties as basic raw material to ensure the basic performance of ceramic;Introduce appropriate amount of calcium carbonate, manganese dioxide and barium carbonate, effectively reduce the dielectric loss of ceramic, and improve its temperature characteristics;The present application reduces production cost and technical difficulty by solid phase reaction method, while ensuring the uniformity and stability of ceramic, effectively reduces the dielectric loss of microwave dielectric ceramic, and improves its temperature characteristics, further improves the performance of ceramic.

This application provides a method for the rapid preparation of lithium manganese iron phosphate (LFP) using molten salt-assisted synthesis, and its applications, relating to the field of lithium battery cathode materials technology. This invention prepares high-performance LFP cathode materials through a one-step, short-time, high-temperature calcination process by controlling the types and proportions of iron, manganese, transition metal, and carbon sources, using a multi-element inorganic salt as the liquid reaction environment for the solid-state reaction. The multi-element inorganic salt forms a molten salt liquid under high-temperature conditions, improving mass transfer kinetics, avoiding secondary calcination, shortening the solid-state sintering reaction time, and alleviating the problem of uneven mass transfer during solid-state sintering. Furthermore, the multi-element inorganic salt and solvent do not participate in the chemical reaction, ensuring the uniformity and stability of the material. This invention features simple process conditions, low equipment requirements, easy process control, and easy large-scale industrial production. The multi-element inorganic salt and solvent are recyclable, making it environmentally friendly, and it reduces the energy consumption and production costs of traditional high-temperature calcination processes, resulting in significant economic benefits.

The application discloses a europium-based molybdate material, a preparation method thereof and application of the europium-based molybdate material in a very low temperature magnetic refrigeration material, and relates to the field of magnetic refrigeration materials. The chemical structural formula of the europium-based molybdate material is EuMoO4, the europium-based molybdate material has a secondary magnetic phase change below 1K temperature, and can be applied to preparation of a very low temperature magnetic refrigeration material. The europium-based molybdate material has a secondary magnetic phase change under the condition of 1K temperature, and the volume magnetic entropy change of the europium-based molybdate material under a low magnetic field is obviously higher than the maximum volume magnetic entropy change of an existing magnetic refrigeration material under the same magnetic field change, so that the europium-based molybdate material is a very low temperature magnetic refrigeration material with excellent performance. The europium-based molybdate material is synthesized by using a solid phase reaction method, the preparation process is simple, energy consumption is low, and the europium-based molybdate material is suitable for large-scale industrial production.

The application discloses a perovskite thermistor material, a preparation method and application thereof. The perovskite thermistor material is prepared from barium carbonate, bismuth oxide, lead oxide, sodium carbonate and potassium carbonate as raw materials by a solid phase reaction method, and has a chemical formula of (Ba 1‑y Re y )(Bi 1‑x R x )O3. In the formula, Re=Pb, 0≤y≤0.1; R=Na, K, 0≤x≤0.15. The perovskite thermistor material has a single perovskite structure. The material can be sintered into a porcelain at a low temperature, and the oxygen vacancies can be effectively adjusted under different sintering atmospheres, so that the material constant and the resistivity of the thermistor ceramic can be significantly reduced, and the perovskite thermistor material can be used for measurement and control in a temperature range of 40-160K at a low temperature.

This invention relates to two-dimensional material preparation technology, specifically to a method for preparing high-quality oxide nanosheets and thin films based on liquid-phase exfoliation. The method involves synthesizing a layered precursor through a solid-phase reaction, followed by ion exchange using a protic acid to replace interlayer metal ions with hydrogen ions, thereby weakening the interlayer forces. Then, efficient and low-defect liquid-phase exfoliation is achieved through gentle mechanical oscillation with an organic base, yielding a single-layer or few-layer oxide nanosheet dispersion. Film formation is then achieved using two different methods: spin coating and layer-by-layer self-assembly. In summary, this invention avoids the damage to the material structure caused by traditional ultrasonic exfoliation and the harm to the human body caused by the use of highly toxic organic solvents. Furthermore, the process is simple, and the method for preparing two-dimensional oxide nanosheets and thin films has a certain degree of universality. The film formation is controllable, and the prepared thin films can be applied to fields such as memristors and optoelectronic devices.

The present application relates to a kind of cyclic solid-phase reaction column systems based on induction heating and its operating method.The system includes reaction column, liquid inlet pipeline, liquid outlet pipeline, circulation pipeline and diaphragm pump or plunger pump or plunger pump and valve arranged in each pipeline, reaction column is filled with solid beads or particles inside, copper induction coil is arranged on its outside, and is electrically connected with induction heating module.Circulation diaphragm pump or plunger pump or plunger pump is started under the condition that liquid inlet valve and liquid outlet valve are closed, to make aqueous solution form closed circulation in reaction column, utilize induction heating module to heat reaction column, realize the uniform circulation and heating of solution in reaction column.It can complete cleaning, reaction and product collection operation in the same reaction column, diaphragm pump or plunger pump can form fluid block in stop working state, with the function of pump and valve.The present application is simple in structure, high in heating efficiency, flexible in operation, and suitable for various solid-phase and aqueous reaction process.

The application belongs to the technical field of sodium ion batteries, and discloses a composite phosphate preparation method, which comprises the following steps: S1. Preparing phosphorus source material, iron source material and sodium source material according to the nominal chemical dosage ratio of Na4Fe3(PO4)2P2O7, and simultaneously preparing carbon source material; then wet ball milling the materials to mix them uniformly, and drying to obtain a precursor; S2. Mixing the precursor with sodium vanadium phosphate powder uniformly, and then performing heat treatment at a temperature of 450 DEG C to 650 DEG C under a protective atmosphere, so that a composite material of Na4Fe3(PO4)2P2O7 and sodium vanadium phosphate is obtained, and the composite material simultaneously comprises Na4Fe3(PO4)2P2O7 phase and sodium vanadium phosphate phase. By introducing sodium vanadium phosphate NVP (not NVP precursor) into the solid phase reaction of NFPP to participate in composite formation to form a composite phosphate, the application can effectively solve the problems of difficulty in synthesizing pure phase of the existing composite sodium iron phosphate, low average voltage, high cost of sodium vanadium phosphate and low capacity.