80 results about "Sodium ferrocyanide" patented technology

The invention provides a preparation method of a manganese-based Prussian blue sodium ion battery positive electrode material, which comprises the following steps: firstly, adding a mixed solution of a part of manganese salt and a chelating agent into a sodium ferrocyanide solution at a first flow rate in a protective atmosphere for reaction; and continuously adding the residual mixed solution of the manganese salt and the chelating agent into the reaction system in the previous step at a first flow rate, adding the mixed solution of the transition metal salt and the chelating agent at a second flow rate, reacting again, and aging to obtain the manganese-based Prussian blue sodium-ion battery positive electrode material. The chelating agent is used for assisting coprecipitation to synthesize the Prussian blue analogue coated manganese-based Prussian blue sodium ion battery positive electrode material with stable heterogeneous lattices, so that the volume change and particle cracking of the positive electrode material in the charging and discharging process can be effectively inhibited in the circulating process, and the structure collapse is prevented; the cycle stability of the positive electrode material in the charge-discharge process is effectively improved, and the cycle life of the battery is prolonged.

The invention belongs to the technical field of sodium-ion battery material preparation, and particularly relates to a sodium-ion battery positive electrode sodium supplementing additive and a preparation method and application thereof. According to the sodium ion battery positive electrode sodium supplement additive, sodium ferrocyanide is used as a main component of the sodium ion battery positive electrode sodium supplement additive, and the sodium ferrocyanide and the first conductive carbon with the specific surface area larger than 1000 m < 2 > / g are subjected to infiltration adsorption and ball-milling mixing with the second conductive carbon with better conductivity, so that the sodium ion battery positive electrode sodium supplement additive is obtained. When a battery positive electrode adopts the positive electrode sodium supplementing additive disclosed by the invention, dissolved metal ions M react with sodium ferrocyanide Na4 [Fe (CN) 6] adhered to the periphery of a positive electrode material to generate Prussian blue Na2M [Fe (CN) 6] small crystals, so that the sodium storage performance can be continuously exerted within a period of time, and the capacity and service life attenuation of the battery can be delayed; na < + > is released in the generation process of the small crystal Na2M [Fe (CN) 6], so that the effect of continuously supplementing sodium in the use process of the sodium-ion battery is achieved, and the capacity fading is further delayed.

This invention belongs to the field of sodium-ion battery material preparation technology, specifically relating to sodium-ion battery cathode sodium supplementation additives, their preparation methods, and applications. The sodium-ion battery cathode sodium supplementation additive of this invention uses sodium ferrocyanide as the main component, and has a specific surface area greater than 1000 m². 2 The first conductive carbon (g) is impregnated and adsorbed, and then ball-milled and mixed with a second conductive carbon with better conductivity to obtain a sodium-ion battery cathode additive. When the cathode of the battery uses the sodium-ion battery additive of this invention, the dissolved metal ions M react with sodium ferrocyanide Na4[Fe(CN)6] adhering to the cathode material to form Prussian blue Na2M[Fe(CN)6] small crystals, which can continuously exert sodium storage performance for a period of time, delaying the capacity and lifespan decay of the battery; and Na is released during the formation of small crystals Na2M[Fe(CN)6]. + It plays a role in continuously replenishing sodium during the use of sodium-ion batteries, further delaying capacity decay.

The present invention relates to a method for producing a composite adsorbent of ferrocyanide of a transition metal in the matrix of silica gel comprising the following steps: (i) preparing a first aqueous composition comprising at least the mixture of a sodium or potassium ferrocyanide with a sodium silicate solution so as to obtain the dissolution of salts; (ii) preparing a second composition comprising the mixture of at least: a transition metal salt chosen from one or more of the following compounds: nickel, copper, zinc, cobalt, and an inorganic acid; (iii) mixing the first aqueous composition with the second composition until a suspension is obtained; (iv) adding an inorganic acid or base so that the suspension obtained at the end of step (iii) has a pH ranging from 4 to 9;(v) demixing the suspension obtained at the end of step (iv) so as to obtain a precipitate within a liquid phase; (vi) separating said precipitate, rinsing and drying the precipitate, so as to obtain a solid precipitate, characterized in that the first aqueous composition comprises a soluble rubidium or cesium salt, and the second composition further comprises a soluble metal salt chosen from one or more of the following compounds: aluminum, titanium, zirconium.;

The invention belongs to the technical field of sodium ion batteries, and particularly relates to a Prussian blue sodium battery positive electrode material and a preparation method thereof.The preparation method comprises the steps that anhydrous sodium ferrocyanide, anhydrous manganese sulfate and a NaA molecular sieve are mixed and preliminarily ground, and a precursor mixture is obtained; placing the precursor mixture in a planetary ball mill for ball milling to obtain a primary reaction product; and washing the preliminary reaction product, and carrying out vacuum drying to obtain the Prussian blue sodium battery positive electrode material. The method is low in material loss and short in generation period, and the prepared Prussian blue sodium battery positive electrode material is low in crystal water content and has good cycle stability.

The invention discloses a lanthanide-doped Prussian blue positive electrode material and a preparation method and application thereof, and the preparation method comprises the following steps: mixing and dissolving sodium ferrocyanide and lanthanide metal salt to obtain a mixed solution; and under a protective atmosphere, dropwise adding the mixed solution into a mixed chelating agent salt solution through a peristaltic pump, and reacting to obtain the lanthanide-doped Prussian blue positive electrode material. The lanthanide metal in the lanthanide-doped Prussian blue positive electrode material occupies the Na site, the single iron source coprecipitation method is adopted for synthesis, the process concentration is uniform, the synthesized positive electrode material has fewer defects, the material structure is stable, the rate capability is excellent, the specific capacity is high, and the application prospect is very good.

The invention provides a preparation method and application of a sodium cobalt hexacyanoferrate composite material based on three-dimensional honeycomb MXene. The composite material is prepared through the following steps that 1, a Ti3AlC2 MAX phase reacts with a mixed solution of lithium fluoride (LiF) and concentrated hydrochloric acid (HCl), an Al atomic layer is removed through etching, and layered MXene is obtained; 2, mixing the layered MXene with a polymethyl methacrylate (PMMA) template, centrifuging, washing, drying and calcining to prepare three-dimensional honeycomb MXene; and 3, dispersing the three-dimensional honeycomb MXene in deionized water, sequentially adding a cobalt source and a sodium ferrocyanide (Na4Fe (CN) 6) solution, and carrying out an in-situ coprecipitation reaction to obtain the composite material. In the composite material, the sodium cobalt hexacyanoferrate is of a cubic structure and is uniformly embedded into a three-dimensional honeycomb MXene framework. The composite material disclosed by the invention is applied to a water-based sodium-ion battery positive electrode material, and has high conductivity, excellent rate capability and cycling stability.

The present invention discloses a Prussian blue-based sodium-ion battery positive electrode material, a preparation method, and applications thereof. The method comprises: mixing sodium ferrocyanide, oxalate, and a non-aqueous solvent, subjecting the mixture to a ball-milling reaction, and washing the product after the ball-milling reaction to remove unreacted raw materials and a portion of sodium oxalate generated by the reaction, thereby obtaining the Prussian blue-based sodium-ion battery positive electrode material. The present invention can synthesize Prussian blue-based compounds with low defects and low interstitial water molecule content, thereby improving the sodium storage performance and capacity utilization of such materials; it also reduces the probability of side reactions in the electrolyte causing cell bloating. In addition, the use of oxalate-based raw materials can also generate a sodium oxalate-based positive electrode sodium supplement during the synthesis of the Prussian blue-based compound, thereby replenishing sodium ion loss caused by SEI film formation or other side reactions during the initial charge.

The invention relates to a production process of a purple pigment with high color fidelity and dyeing uniformity. Comprising the following steps: 1) adding a copper sulfate solution into a dissolving solution containing basic purple 5BN and basic fuchsin, uniformly stirring, and heating to 78-85 DEG C to obtain a material A; (2) adding the sodium ferrocyanide solution into the material A in 70-90 minutes, maintaining the temperature, and uniformly stirring to obtain a material B; 3) adding the sodium sulfite solution into the material B, continuously stirring uniformly, adding the sodium ferrocyanide solution again, and stirring uniformly to obtain a material C; the preparation method comprises the following steps of 1, adding a material C into a reaction kettle, 2, adding ammonia water into the material C, adjusting the pH value to 7.5-8, and stirring for 25-35 min to obtain a material D, 5, maintaining the temperature of the material D, and carrying out emulsification dispersion treatment to obtain a material E, and 6, cooling the material E to a temperature below 60 DEG C to obtain a material F, and carrying out post-treatment on the material F to obtain the pink purple pigment. The pigment obtained through the above scheme has high purple color fidelity and dyeing uniformity.

The application discloses a nickel-based Prussian blue battery positive electrode material and a preparation method and battery thereof, and belongs to the technical field of batteries, wherein the preparation method of the nickel-based Prussian blue battery positive electrode material comprises the following steps: dissolving sodium citrate into a nickel chloride solution to obtain reagent A; dissolving sodium ferrocyanide in water to prepare a solution to obtain reagent B; dissolving polyvinylpyrrolidone in a sodium chloride solution to obtain reagent C; simultaneously and slowly adding the reagent A and the reagent B into the reagent C to obtain a suspension liquid and aging the suspension liquid; centrifugally separating the suspension liquid after aging, washing, drying and grinding to obtain the nickel-based Prussian blue battery positive electrode material; and the nickel-based Prussian blue battery positive electrode material prepared by the application has the characteristics of high capacity, low alternating current impedance and high long cycle stability, and has excellent electrochemical performance.

The invention belongs to the technical field of energy materials, and particularly relates to preparation and application of a high-crystallinity long-life Prussian blue and analogue positive electrode material thereof. Aiming at the defects in the prior art, the invention provides the preparation method of the high-crystallinity long-life Prussian blue and the analogue thereof, which comprises the following steps: 1) mixing soluble transition metal M salt and a solvent to obtain a solution A; 2) mixing sodium ferrocyanide salt, sodium salt and a solvent to obtain a solution B; adding a complexing agent or / and an acid for regulating and controlling the chelating ability into the solution A, adding a complexing agent or / and an acid for regulating and controlling the chelating ability into the solution B, and controlling the total molar ratio of the complexing agent to the acid for regulating and controlling the chelating ability in the solution A and the solution B to be (20-1): 1; and 3) dropwise adding the solution A into the solution B, reacting, aging, centrifuging, washing and drying to obtain the Prussian blue and the analogue thereof. The method disclosed by the invention greatly widens the selection range of the chelating agent in the production process of the Prussian blue analogue positive electrode.

The application discloses a kind of low-defect manganese-based prussian blue under solid-liquid dynamic balance fast preparation method, comprising the following steps: S1, sodium citrate is dissolved in deionized water, then add manganese acetate and ascorbic acid, form the solution A containing manganese complex;Wherein, the molar ratio of sodium citrate, manganese acetate and ascorbic acid is (4.5-5.5): 1:(0.3-0.4);S2, sodium ferrocyanide is added to deionized water, stirring is formed at a set temperature containing unsolved sodium ferrocyanide solid supersaturated suspension B;Wherein, the addition amount of sodium ferrocyanide is far more than its saturated solubility at the temperature, so that the system maintains solid-liquid two-phase equilibrium state;Crystalline integrity is higher: thanks to "whole process dynamic saturation" environment, the manganese-based prussian blue prepared by the application has more obvious monoclinic phase characteristics (corresponding XRD double peak is obvious, intensity is obvious, signal-to-noise ratio is good) compared with comparative document, lattice vacancy and coordination water content are significantly lower than comparative document scheme, and electronic conductivity is increased by nearly 50%.

The application relates to the technical field of sodium ion battery electrode materials, in particular to a polyaniline-coated Prussian blue analogue positive electrode material for a sodium ion battery and a preparation method thereof. The material is synthesized by using a room-temperature co-precipitation method combined with an in-situ oxidation polymerization method, and comprises the following steps: step one, dissolving ferrous sulfate heptahydrate and sodium citrate in deionized water to obtain solution 1; step two, dissolving sodium ferrocyanide decahydrate in deionized water to obtain solution 2. The PBA@PANI composite material is used as a positive electrode of a sodium ion battery, and in the cycle test, the PBA@PANI composite material exhibits a significantly improved capacity retention rate, excellent rate performance and a stable working voltage platform. Meanwhile, the polyaniline-coated Prussian blue analogue composite material prepared by the process has high specific capacity and long cycle life, and provides an efficient solution for the practical application of a high-performance and low-cost sodium ion battery positive electrode material.

The invention relates to a preparation method and application of a Prussian blue material, and belongs to the field of new battery materials. The method aims to solve the technical problems that an existing preparation method is long in reaction time and harsh in process condition and has the risk of cyanide generation. A mixed solution prepared from a chelate and a cyanogen source is placed in a microwave reactor, the temperature is raised to 20-180 DEG C at the speed of 1-10 DEG C / min, heat preservation is conducted for 1-60 min, the Prussian blue material is prepared, the chelate is selected from glycine and ethylenediamine tetraacetic acid, and the cyanogen source comprises compounds such as sodium ferrocyanide. The performance of the material is synergistically optimized by adding a sodium source, a reducing agent and a surfactant. According to the preparation method, the process energy consumption is low, the risk of cyanide generation is avoided, the obtained material shows excellent performance in a sodium ion battery, 67.39% of capacity is kept after 400 times of circulation under the current density of 200mA / g, and a rate test shows that the discharge specific capacity of 78.92 mAh / g is still kept at the discharge specific capacity of 800mA / g. According to the invention, efficient and safe preparation of the Prussian blue material and large-scale application of the Prussian blue material in energy storage devices are realized.

The invention discloses a vacancy content controllable Prussian blue crystal as well as a preparation method and application thereof, and belongs to the technical field of material synthesis. In order to solve the technical problems that the vacancy content of a prussian blue material is difficult to accurately control and a vacancy-free material is difficult to prepare, the invention provides a series of prussian blue crystals with controllable vacancy content, and the preparation method comprises the following steps: mixing sodium ferrocyanide, a complexing agent, a sodium salt and water to obtain a solution A; mixing soluble manganese salt, soluble ferrous salt, a complexing agent, sodium salt and water to obtain a solution B; and controlling the sodium ion concentration and the reaction atmosphere and temperature, adding the solution A into the solution B, reacting, and aging to obtain the Prussian blue crystal. According to the method, the sodium ion concentration, the reaction atmosphere and the temperature are regulated and controlled by changing the addition amount of the sodium salt and the like, and the crystal growth speed and the ion transmission speed in the coprecipitation reaction are controlled, so that the purpose of accurately controlling the vacancy content is achieved, and a material without vacancy and first-stage crystal water can be prepared.

The invention discloses a preparation method and application of a Prussian blue positive electrode material, and belongs to the field of sodium ion batteries. The preparation method comprises the following steps: dissolving sodium ferrocyanide, a coated surfactant, a weakly acidic complexing agent and an amphoteric organic compound in a mixed solvent of ethanol and water to prepare a precursor solution; and carrying out hydrothermal treatment on the precursor solution, centrifuging with a cleaning agent until the supernatant is clear, and drying to obtain the Prussian blue positive electrode material. The preparation method particularly pays attention to inhibition of generation of high-toxicity byproducts such as HCN and NaCN in the hydrothermal synthesis process, so that the purity of the Prussian blue is improved, and the Prussian blue positive electrode material has less internal crystal water and [Fe (CN) 6] < 4-> defect vacancy, so that the Prussian blue positive electrode material shows excellent high charge-discharge capacity and long-term cycle stability.

The application provides a single crystal type high-entropy Prussian blue positive electrode material and a preparation method and application thereof, and the preparation method comprises the following steps: mixing a transition metal salt solution, a sodium ferrocyanide solution, a complexing agent solution, a base solution and a precipitant, performing a co-precipitation reaction under the condition that the pH value is 10-13, then performing standing and aging, and sequentially performing filtration, washing and drying to obtain the single crystal type high-entropy Prussian blue positive electrode material. The single crystal type high-entropy Prussian blue positive electrode material obtained by the application has a high material thermal decomposition temperature and excellent thermal stability; vacancies in the positive electrode material and a small amount of water content can inhibit the dissolution of metals; in addition, the single crystal type high-entropy Prussian blue positive electrode material obtained by the application has excellent morphology.

The application provides a preparation method of a sodium-rich and low-water-content Prussian blue positive electrode material, which comprises the following steps: dissolving sodium ferrocyanide or a hydrate thereof and a complexing agent in deoxygenated water under an inert gas atmosphere and at a certain temperature to obtain a mixed solution A; dissolving a transition metal salt or a hydrate thereof, a sodium supplementing agent, a complexing agent and an auxiliary complexing agent in deoxygenated water under an inert gas atmosphere and at a certain temperature to obtain a mixed solution B; continuously stirring solution A and solution B by dropwise adding them into a container with a positive pressure inert gas atmosphere and at a certain temperature, continuing to stir for a period of time after the dropwise adding is completed, and then standing, centrifuging and vacuum drying to obtain the Prussian blue positive electrode material. The Prussian blue positive electrode material comprises a mixed phase structure of rhombic phases and cubic phases, has the characteristics of high sodium content and low water content. The battery assembled by using the positive electrode material obtained by the method has a theoretical specific capacity close to the theoretical specific capacity under a small current density and still has a high specific capacity under a large current density.

The preparation method comprises the following steps: (1) uniformly dispersing a carbon source / nitrogen source, an iron salt and a nickel salt in ethanol, drying, and calcining in an inert atmosphere to obtain FeNi-coated NCT; and (2) dispersing the FeNi-coated NCT in a sodium ferrocyanide aqueous solution, adjusting the pH value, standing, washing with deionized water, and drying to obtain the Prussian blue compound which is also known as FeNiPBA / NCT. The preparation method disclosed by the invention is simple, efficient, green, high in component adjustability, high in process expandability and easy to amplify. The high-crystallinity and high-conductivity Prussian blue compound prepared by the preparation method disclosed by the invention is used as a positive electrode material, so that the rate capability and the cycle life of a sodium ion battery are remarkably improved, the electrochemical performance of the Prussian blue compound is far better than that of a Prussian blue positive electrode material prepared by a conventional modification strategy, and the technical defects of the Prussian blue positive electrode material in the sodium ion battery at present are overcome.

The present invention relates to a process for producing a composite ferrocyanide adsorbent of a transition metal in the silica gel matrix comprising the following steps: (i) the preparation of a first aqueous composition comprising at least a mixture of a sodium or potassium ferrocyanide with a sodium silicate solution so as to obtain the dissolution of salts; (ii) the preparation of a second composition comprising a mixture of at least: a transition metal salt selected from one or more of the following compounds: nickel, copper, zinc, cobalt, and an inorganic acid; (iii) the mixing of the first aqueous composition with the second composition until a suspension is obtained; (iv) the addition of an inorganic acid or base so that the suspension obtained at the end of step (iii) has a pH ranging from 4 to 9;(v) the separation of the suspension obtained at the end of step (iv) so as to obtain a precipitate within a liquid phase; (vi) the separation of said precipitate, the rinsing and drying of the precipitate, so as to obtain a solid precipitate, characterized in that the first aqueous composition comprises a soluble salt of rubidium or cesium, and the second composition further comprises a soluble salt of metal selected from one or more of the following compounds: aluminium, titanium, zirconium.;

The molecular formula of the positive electrode material is NaxM [Fe (CN) 6] y (M is a transition metal ion, x is greater than or equal to 0 and less than or equal to 2, and y is greater than or equal to 0.9 and less than or equal to 1). The synthesis method comprises the following steps: dissolving transition metal salt, sodium salt and a complexing agent in deionized water to form a solution A; sodium ferrocyanide / sodium ferricyanide is dissolved in deionized water to form a solution B; and dropwise adding the solution A into the solution B, stirring / standing for aging, washing the obtained precipitate for multiple times, and drying to obtain the medium-entropy Prussian blue-based positive electrode material. According to the invention, a complexing agent assists a coprecipitation method to slow down the nucleation and growth rate of the material, so that the content of [Fe (CN) 6] anion vacancy and coordinated water molecules is obviously reduced, and controllable synthesis of the low-defect high-crystallization Prussian blue analogue material is realized; and the phase change behavior and the serious ginger-Taylor effect in the sodium ion storage process are effectively inhibited by the medium entropy stability and the multi-element synergistic effect, so that the positive electrode material has high reversible specific capacity, excellent rate capability and cycling stability.

A method for preparing a Prussian blue-based sodium-ion battery cathode material with both high capacity and long cycle performance, belonging to the field of sodium-ion batteries, includes the following steps: Step 1, preparing a sodium ferrocyanide solution, denoted as solution A; Step 2, dissolving a transition metal divalent ferric salt, a doped metal salt, ascorbic acid, and a complexing agent in deionized water, denoted as solution B; Step 3, preparing an aqueous solution of the complexing agent, denoted as solution C; Step 4, simultaneously adding solutions A and B in equal molar amounts to solution C for a co-precipitation reaction, aging the solution to obtain a suspension, separating the suspension to obtain the Prussian blue-based sodium-ion battery cathode material with both high capacity and long cycle performance. This invention proposes a synthesis method that only requires co-precipitation through a combination of slow crystallization and ion doping to obtain a low-cost, non-toxic, harmless, simple preparation process, short production cycle, and Prussian blue-based sodium-ion cathode material with both high capacity and long cycle performance.

The invention discloses a rapid preparation method of low-defect manganese-based Prussian blue under solid-liquid dynamic equilibrium, which comprises the following steps: S1, dissolving sodium citrate in deionized water, and then adding manganese acetate and ascorbic acid to form a solution A containing a manganese complex; wherein the molar ratio of the sodium citrate to the manganese acetate to the ascorbic acid is (4.5-5.5): 1: (0.3-0.4); s2, adding sodium ferrocyanide into deionized water, and stirring at a set temperature to form a supersaturated turbid liquid B containing an undissolved sodium ferrocyanide solid; wherein the addition amount of the sodium ferrocyanide far exceeds the saturation solubility of the sodium ferrocyanide at the temperature, so that the system is kept in a solid-liquid two-phase equilibrium state; benefited from the whole-process dynamic saturation environment, compared with a comparison file, the manganese-based Prussian blue prepared by the method has more obvious monoclinic phase characteristics (corresponding to obvious XRD double peaks, obvious strength and good signal-to-noise ratio), the lattice vacancy and coordinated water content are obviously lower than those of a comparison file scheme, and the electronic conductivity is increased by nearly 50%.

The invention provides a Prussian blue sodium ion material and a preparation method and application thereof.According to the method, the reversible adsorption characteristic of an MOF material on alkaline earth metal ions or transition metal ions is utilized, and the alkaline earth metal ions or transition metal ions are adsorbed into the MOF material; and reacting the MOF material adsorbed with the alkaline earth metal ions or the transition metal ions with sodium ferrocyanide to generate the Prussian blue sodium ion material. In the process of generating the Prussian blue sodium ion material, the MOF material can slowly release metal ions adsorbed in the MOF material into a reaction system, so that the generation speed of the Prussian blue sodium ion material is slowed down, and the lattice defects and the vacancy content of the Prussian blue sodium ion material are further controlled. According to the method, a chelating agent does not need to be additionally added, lattice defects and vacancy content in the Prussian blue sodium ion material can be effectively controlled on the premise of not increasing the cost, and when the Prussian blue sodium ion material is applied to the sodium ion battery, the capacity and cycling stability of the sodium ion battery can be effectively improved.

The invention discloses an anode catalyst as well as a rapid Joule heat preparation method and application thereof. Mixing the nickel ion solution with the iron ion solution to obtain a mixed metal ion solution; dropwise adding the mixed metal ion solution into a sodium ferrocyanide solution, mixing and dispersing, and carrying out centrifugal separation and drying to obtain a precursor material; the foamed nickel is sequentially subjected to ethanol ultrasonic treatment and then immersed in nitric acid for ultrasonic cleaning; and mixing the pretreated foamed nickel with the precursor material obtained in the step 1, carrying out rapid Joule heat treatment under the protection of inert gas, and cooling to obtain the anode catalyst. The anode catalyst material prepared through rapid Joule heat treatment shows excellent electrochemical (OER) oxygen evolution reaction catalytic performance, the overpotential reaches 220 mV under the current density of 10 mA cm <-2 >, and compared with a commercial anode catalyst material prepared through a traditional method, the overpotential is reduced by about 30-100 mV.

The application discloses hollow iron-based Prussian blue and a template-free preparation method and application thereof. The preparation method comprises the following steps: S1, preparing a sodium ferrocyanide solution to obtain solution A; S2, mixing a soluble divalent iron salt, sodium citrate and deionized water to obtain solution B; S3, quickly pouring solution B into solution A and mixing and stirring to obtain a Prussian blue suspension; and S4, aging and post-treating the suspension to obtain a material. The concentration of the sodium ferrocyanide in solution A is 0.02-0.04 mol / L; the molar ratio of the divalent iron salt in solution B to the sodium ferrocyanide in solution A is (1.4-1.5):1; and the molar ratio of the sodium citrate to the sodium ferrocyanide in solution A is (5-10):1. The iron-based hollow cubic Prussian blue is prepared through one-step co-precipitation without a template, has a large specific surface area, is beneficial to exposing more active sites, and has a shorter ion diffusion path.

The invention discloses a low-potential Prussian blue positive electrode material as well as a preparation method and application thereof. The preparation method comprises the following steps: mixing a precipitant solution and a metal salt solution to carry out coprecipitation reaction, filtering and washing to obtain a washed filter cake; and adding the washed filter cake into a treatment solution containing sodium ferrocyanide for pulping, carrying out high-temperature aging treatment under a stirring condition, and then carrying out filtering, washing and drying treatment to prepare the low-potential Prussian blue positive electrode material. In the washing process of a conventional coprecipitation method, the steps of pulping and high-temperature aging in a solution environment containing sodium ferrocyanide are introduced, and ferrocyanide vacancies in a lattice structure are reduced through curing and ion exchange; meanwhile, the method disclosed by the invention is based on an existing technological process, no additional working procedure is added, a solution environment containing sodium ferrocyanide is introduced into an inherent pulping flow of a washing working procedure, and only one-time drying is needed in the whole process.

The invention belongs to the technical field of sodium ion battery electrode materials, and particularly provides a preparation method for synthesizing a Prussian blue analogue sodium ion battery positive electrode material under the assistance of reduced iron powder. The process comprises the following core steps: respectively dissolving sodium ferrocyanide, an iron source compound, reduced iron powder and a complexing stabilizer in deionized water to prepare a precursor solution system; the target product is obtained through the procedures of aging treatment, solid-liquid separation, vacuum drying and the like after multiphase coprecipitation reaction. The material can be used as a high-performance positive electrode active material to be applied to a sodium ion secondary battery system. According to the scheme, a coordination regulation strategy is combined with a coprecipitation technology, precise construction of a material structure is realized by utilizing a regulation function (providing a reduction environment and regulating the valence state of iron in a reaction system) of reduced iron powder, the structural stability of the Prussian blue analogue compound in a long-cycle process is remarkably improved, defects are reduced, and the crystallinity is improved.

The present invention relates to a method for producing a composite adsorbent of ferrocyanide of a transition metal in a silica gel matrix, the method comprising the following steps: (i) preparing a first aqueous composition comprising at least the mixture of a sodium or potassium ferrocyanide with a sodium silicate solution so as to dissolve the salts; (ii) preparing a second composition comprising the mixture of at least: a salt of a transition metal selected from one or more of the following compounds: nickel, copper, zinc, cobalt and an inorganic acid; (iii) mixing the first aqueous composition with the second composition until a suspension is obtained; (iv) adding an inorganic acid or base such that the suspension obtained at the end of step (iii) has a pH ranging from 4 to 9; (v) demixing the suspension obtained at the end of step (iv) so as to obtain a precipitate in a liquid phase; (vi) separating the precipitate and rinsing and drying the precipitate so as to obtain a solid precipitate, characterised in that the first aqueous composition comprises a soluble salt of rubidium or cesium, and the second composition further comprises a soluble salt of a metal selected from one or more of the following compounds: aluminium, titanium, zirconium.

The present invention relates to a method for manufacturing a Prussian blue cathode material for sodium batteries using a Taylor reactor. More specifically, the method includes a first mixture preparation step of preparing a first mixture containing an aqueous iron chloride solution, a second mixture preparation step of preparing a second mixture containing an aqueous sodium ferrocyanide solution, a synthesis step of introducing the mixtures prepared in the first mixture preparation step and the second mixture preparation step into a Taylor reactor and reacting them under nitrogen injection conditions to synthesize a Prussian blue analog, a aging step of aging the Prussian blue analog prepared in the synthesis step, a washing and filtration step of washing and filtration the aged Prussian blue analog with a detergent, and a drying step of drying the washed and filtrated Prussian blue analog. The method for manufacturing a Prussian blue cathode material for sodium batteries using the above steps provides a Prussian blue cathode material that exhibits excellent production efficiency and provides sodium batteries with improved charge / discharge efficiency and capacity retention.