CN116706056A - Based on ultra-small particles Na x Fe y M z (SO 4 ) 3 Non-destructive quick-charging positive electrode material, and preparation method and application thereof - Google Patents

Based on ultra-small particles Na x Fe y M z (SO 4 ) 3 Non-destructive quick-charging positive electrode material, and preparation method and application thereof Download PDF

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CN116706056A
CN116706056A CN202310700076.4A CN202310700076A CN116706056A CN 116706056 A CN116706056 A CN 116706056A CN 202310700076 A CN202310700076 A CN 202310700076A CN 116706056 A CN116706056 A CN 116706056A
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sodium
positive electrode
electrode material
sulfate
ferric
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陈冲
姚文娇
许欢
吴南中
唐永炳
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Shenzhen Institute of Advanced Technology of CAS
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Shenzhen Institute of Advanced Technology of CAS
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G49/00—Compounds of iron
    • C01G49/009—Compounds containing, besides iron, two or more other elements, with the exception of oxygen or hydrogen
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G51/00—Compounds of cobalt
    • C01G51/006—Compounds containing, besides cobalt, two or more other elements, with the exception of oxygen or hydrogen
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00—Compounds of nickel
    • C01G53/006—Compounds containing, besides nickel, two or more other elements, with the exception of oxygen or hydrogen
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/03—Particle morphology depicted by an image obtained by SEM
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/64—Nanometer sized, i.e. from 1-100 nanometer
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Abstract

The invention belongs to the field of electrode materials, and particularly discloses an ultra-small particle Na-based electrode material x Fe y M z (SO 4 ) 3 Is a lossless fast-charging positive electrode material, and a preparation method and application thereof. The molecular formula of the positive electrode material is Na x Fe y M z (SO 4 ) 3 Wherein x is more than or equal to 1.0 and less than or equal to 3.0,0.5, y is more than or equal to 2.0,0.5 and z is more than or equal to 1.5, and M is transition metal; and the particle size of the positive electrode material is between 10 and 80 nm. The invention synthesizes the ultra-small particle Na by the methods of low-temperature solvothermal, flash drying and low-temperature calcination x Fe y M z (SO 4 ) 3 The non-destructive fast-charging positive electrode material is used in a sodium ion battery, and the ultra-small particle size is favorable for shortening the diffusion paths of ions and electrons, so that the fast transmission of sodium ions is realized; in addition, the partial substitution of the transition metal ions further improves the reactivity of the material, thereby improving the rate capability of the material.

Description

Based on ultra-small particles Na x Fe y M z (SO 4 ) 3 Non-destructive quick-charging positive electrode material, and preparation method and application thereof
Technical Field
The invention belongs to the field of electrode materials, and particularly relates to an ultra-small particle Na-based electrode material x Fe y M z (SO 4 ) 3 Is a lossless fast-charging positive electrode material, and a preparation method and application thereof.
Background
Lithium ion batteries are widely used in the fields of portable electronic devices, electric automobiles and the like due to small size, light weight and high energy density, but the large-scale development of the lithium ion batteries is limited due to lack of global lithium resources and uneven distribution. The structure and the working mechanism of the sodium ion battery are similar to those of the lithium ion battery, and the sodium ion battery is based on a rocking chair type electrochemical energy storage mechanism; in addition, sodium resources are abundant and low in cost, so that the development and heating of a sodium ion battery are accelerated. The positive electrode material of the sodium ion battery is the most important link of the whole sodium ion battery system, and determines the performance of the sodium ion battery to a great extent, including cost, energy density, multiplying power, cycle life and the like. The ideal battery positive electrode material should have the following characteristics: first, active sodium ions can be provided. Second, having the appropriate valence-changing element provides a relatively high redox potential in order to achieve a high battery operating voltage and energy density. Third, it is desirable to be able to safely store in air and be non-toxic, which is a trend of green chemistry, and is a mainstream of future development, while stable storage is greatly advantageous for uniformity of the battery. The development of sodium ion anode materials with low cost, high electrochemical reversibility and long cycle life is the difficulty, key point and hot spot of current domestic and foreign research.
In recent years, reports on positive electrode materials of sodium ion batteries mainly include layered oxides, prussian blue systems, and polyanion systems. Layered oxides such as Na x VO 2 ，Na x MnO 2 And the like, because the layered frameworks are connected by only weak ionic bonds, irreversible phase change easily occurs in the electrochemical process, and the cycle performance is insufficient. Prussian blue systems, e.g. Na 1.72 MnFe(CN) 6 Etc. are easily formed in the structure [ Fe (CN) 6 ]Vacancies and are easily occupied by crystal water, resulting in poor cell cycle performance and low coulombic efficiency. The vanadium sodium phosphate anode material in the polyanion system has a certain resource shortage risk due to the scarcity of the required vanadium element crust resource, and the vanadium is not friendly to the environment, so that the use risk is increased. Therefore, there is a need for a positive electrode material of a sodium ion battery capable of satisfying industrial production, being environment-friendly, having low cost and having excellent electrochemical properties to satisfy the application requirements of the sodium ion battery.
The sodium element, the iron element and the sulfur element required by the sodium iron sulfate are all elements rich in crust resources, so the sodium iron sulfate has the intrinsic advantage of low raw material cost. In addition, due to sulfate to Fe 2+ /Fe 3+ The strong induction effect is that the sodium ferric sulfate has the working voltage of 3.8V in the iron-based polyanion type positive electrode material, and the proper theoretical specific capacity of 120mAh g -1 The theoretical energy density of the positive electrode material is as high as 456Wh/kg, and is inferior to that of the lithium iron phosphate positive electrode. However, the particle size of the sodium ferric sulfate material synthesized by the prior art is larger, the material utilization rate is low, the poor multiplying power performance, the circulation stability, the low sodium storage specific capacity and the like of the material are caused, and the industrialization process is seriously influenced.
In order to further promote the practical application of the sodium iron sulfate as the positive electrode material of the sodium ion battery, the modification of the sodium iron sulfate is important. In recent years, many researches have been carried out to regulate the electrochemical properties of sodium iron sulfate materials through strategies such as ion doping, coating and the like. Cao et al spray-dried on three-dimensional graphene micro-netWherein the Na coated by the graphene is constructed 2.4 Fe 1.8 (SO 4 ) 3 And (3) nanoparticles. The unique micro-nano structure and component advantages of the material enable the electrode to show better multiplying power property and long cycle life, but the whole preparation process takes too long, lasts about 48 hours, and requires more severe conditions, and requires processes such as spray drying (J.energy chem.,2021,54,564). The Chinese patent publication No. CN 106058251A discloses a core-shell structure Na 2 Fe 2 (SO 4 ) 3 The preparation method of the @ alumina composite material has good physical and chemical properties, but the addition of the alumina can lead to the reduction of the energy density of the material, and the discharge specific capacity of the final electrode is 69mAh g -1 Left and right. In addition, the existing synthetic method of the sodium iron sulfate material needs higher temperature and has low safety coefficient; and the prepared material has larger particle size, so that the material has lower utilization rate and poorer electrical property, and the requirement of high-rate charge and discharge is difficult to meet.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems in the prior art described above. For this purpose, the invention proposes a process based on ultra-small particles Na x Fe y M z (SO 4 ) 3 The lossless fast-charging positive electrode material, the preparation method and the application thereof synthesize the ultra-small particle Na through the methods of low-temperature solvothermal, flash drying and low-temperature calcination x Fe y M z (SO 4 ) 3 The non-destructive fast-charging positive electrode material is used in a sodium ion battery, and the ultra-small particle size is favorable for shortening the diffusion paths of ions and electrons, so that the fast transmission of sodium ions is realized; in addition, the partial substitution of the transition metal ions further improves the reactivity of the material, thereby improving the rate capability of the material.
To solve the above problems, a first aspect of the present invention provides a positive electrode material having a molecular formula of Na x Fe y M z (SO 4 ) 3 Wherein x is more than or equal to 1.0 and less than or equal to 3.0,0.5, y is more than or equal to 2.0,0.5 and z is more than or equal to 1.5, and M is transition metal; the particle size of the positive electrode material is between 10 and 80 nm.
Specifically, the particle size of the positive electrode material is in the nanometer level, and the electrode material with the nanometer structure has a shorter ion diffusion path and a larger specific surface area, is beneficial to the rapid transmission of sodium ions, can provide rich active energy storage sites, and improves the specific capacity of the material. Meanwhile, the nano structure of the positive electrode material is beneficial to relieving volume expansion caused in the process of sodium ion intercalation and deintercalation, so that the cycle performance is improved. In addition, the invention utilizes transition metal ions to partially replace iron ions so as to further improve the reactivity of the material, thereby improving the rate capability of the material.
Preferably, the transition metal is selected from at least one of Sc, ti, V, cr, mn, co, ni, cu, zn, ag, pt, au, hg.
More preferably, x=2.0, y=1, z=1; and the transition metal is at least one of Mn and Ni.
A second aspect of the present invention provides a method for preparing a positive electrode material, for preparing the positive electrode material according to the first aspect, comprising the steps of:
(1) Dispersing a sodium source, an iron source, a transition metal source and a sulfur source in a solvent to obtain a suspension;
(2) Heating the suspension to perform solvothermal reaction; separating, washing and flash drying the product of the solvothermal reaction in sequence after cooling to obtain Na-based catalyst x Fe y M z (SO 4 ) 3 Is a powder particle of (2);
(3) And calcining the powder particles under the protection of inert gas atmosphere to obtain the anode material.
Specifically, the invention synthesizes the ultra-small particle Na by adopting the methods of low-temperature solvothermal, flash drying and low-temperature calcination x Fe y M z (SO 4 ) 3 Is used for lossless and rapid charging of the positive electrode material. Compared with the severe conditions of high preparation temperature, long time and the like in the prior art, the preparation method provided by the invention is simple and feasible, has low energy consumption, material cost and equipment requirements, and is more suitable for large-scale industrial production. Wherein the precursor can be heated in a solvent at a low temperatureThe mixture in the solvent is more uniform, so that the uniformity of the synthesized product is ensured; the reaction activity of the product can be further improved by adding a transition metal source; flash drying is beneficial to reducing the content of crystal water in the product in batches and rapidly, promoting a large amount of nucleation of solid substances and preventing crystal growth, so that a precursor of ultra-small particles is formed; calcination in an inert gas atmosphere can promote the reaction of the precursors to produce the product and improve the recycling performance of the product.
Preferably, the sodium source is selected from the group consisting of sodium sulfate, sodium bisulfate, sodium carbonate, sodium bicarbonate, sodium acetate, sodium chloride, sodium phosphate, sodium nitrate, sodium phosphite, sodium formate, sodium propionate, sodium acrylate, sodium benzoate, sodium hypochlorite, sodium chlorate, sodium thiosulfate, sodium persulfate, sodium silicate, sodium bromate, sodium bromide, sodium iodide, sodium fluoride, sodium bisulfate, sodium nitrite, sodium oxalate, sodium persulfate, sodium hydroxide, sodium pyrosulfate, sodium dihydrogen phosphate, disodium hydrogen phosphate, sodium metabisulfite, sodium pyrophosphate, sodium hydrogen phthalate, sodium hydrogen oxalate, sodium sulfite, sodium sorbate, trisodium phosphate, sodium gluconate, sodium oleate, and hydrates of at least one of the foregoing.
More preferably, the sodium source is at least one of sodium sulfate, sodium bisulfate, and sodium bicarbonate.
Preferably, the iron source is selected from the group consisting of ferric sulfate, ferrous oxide, ferric chloride, ferric nitrate, ferric acetate, ferrous bromide, ferrous nitrate, ferrous phosphate, ferrous iodide, ferrous acetate, ferric metasilicate, ferric metatitanate, ferric disodium sulfate, ferrous ammonium sulfate, ferrous carbonate, ferrous chloride, ferrous sulfate, ferrous hydroxide, ferric oxide, ferric dioxide, ferric trichloride, ferric hydroxide, and hydrates of at least one of the foregoing.
More preferably, the iron source is ferrous sulfate.
Preferably, the transition metal source is selected from soluble salts of scandium, titanium, vanadium, chromium, manganese, cobalt, nickel, copper, zinc, silver, platinum, gold, mercury, and hydrates of at least one of the foregoing.
More preferably, the transition metal source is at least one of manganese sulfate and nickel sulfate.
Preferably, the sulfur source is selected from the group consisting of iron sulfate, ferrous sulfate, sodium bisulfate, potassium sulfate, iron dithionite, iron thiosulfate, iron dithionite, iron tetrasulfide, sodium sulfate, sodium sulfite, sodium dithionite, sulfurous acid, sulfuric acid, ammonium persulfate, potassium persulfate, sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, and hydrates of at least one of the foregoing.
More preferably, the sulfur source is ferrous sulfate and/or sodium bisulfate.
Preferably, the molar ratio of the sodium source, the iron source, the transition metal source and the sulfur source is (1-3): (0.5-2): (0.5-1.5): 3.
more preferably, the molar ratio of the sodium source, the iron source, the transition metal source and the sulfur source is 2:1:1:3.
preferably, the solvent is at least one selected from water, methanol, ethanol, acetone, ethylene glycol, and pyridine.
More preferably, the solvent is water.
Preferably, in the step (2), the temperature of the solvothermal reaction is 40-220 ℃; more preferably, the solvothermal reaction temperature is 40-220 ℃.
Preferably, in the step (2), the solvothermal reaction time is 4-12h; more preferably, the solvothermal reaction time is 4-8 hours.
Preferably, in step (2), the flash-dried inlet material has a water content of from 5 to 40wt%; more preferably, the flash-dried inlet material has a water content of from 5 to 15wt%.
Preferably, in step (2), the flash drying chamber has a size of 0.5-10m 3 The method comprises the steps of carrying out a first treatment on the surface of the More preferably, the flash drying chamber has a size of 1-3m 3 。
Preferably, in the step (2), the flash drying temperature is 120-350 ℃; more preferably, the flash drying temperature is 120-200 ℃.
Preferably, in the step (2), the flash drying time is 0.2-6h; more preferably, the flash drying time is 0.2 to 1 hour.
Preferably, in the step (2), the gas flow rate of the flash drying is 1-30m/s; more preferably, the flash-dried gas flow rate is 1-10m/s.
Preferably, in the step (3), the temperature of the calcination treatment is 200-400 ℃; more preferably, the temperature of the calcination treatment is 250-350 ℃.
Preferably, in the step (3), the temperature rising rate of the calcination treatment is 0.5-10 ℃/min; more preferably, the temperature rise rate of the calcination treatment is 1 to 4 ℃/min.
Preferably, in the step (3), the calcination treatment time is 2-48 hours; more preferably, the calcination treatment is for a period of 4 to 12 hours.
Preferably, in step (3), the inert gas is at least one of nitrogen, argon, a mixed gas of argon and hydrogen.
The third aspect of the invention provides a positive electrode plate of a sodium ion battery, which comprises a current collector and a positive electrode material layer coated on the surface of the current collector; the positive electrode material layer contains a positive electrode active material, and the positive electrode active material is the positive electrode material according to the first aspect.
Preferably, the positive electrode material layer further contains a conductive agent and a binder.
The invention has no special requirements on the conductive agent and the adhesive, and the conductive agent (such as conductive carbon black, conductive carbon spheres, conductive graphite, conductive carbon fibers, graphene, reduced graphene oxide and the like) and the adhesive (such as polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl alcohol, carboxymethyl cellulose, SBR rubber, polyolefin and the like) which are commonly used for the positive electrode plate of the sodium ion battery are adopted.
A fourth aspect of the invention provides a sodium ion battery comprising the positive electrode sheet of the sodium ion battery of the third aspect.
A fifth aspect of the invention provides the use of a sodium ion battery as described in the fourth aspect.
Preferably, the application comprises a mobile electronic communication device, an electric vehicle, an electric bicycle, an energy storage battery, a power battery or an energy storage power station.
Compared with the prior art, the technical scheme of the invention has at least the following technical effects or advantages:
(1) The anode material of the invention is transition metal partially substituted sodium iron sulfate Na x Fe y M z (SO 4 ) 3 The material has the particle size of nanoscale ultra-small particles, greatly shortens the diffusion distance of ions/electrons, electrolyte and other substances, reduces the diffusion barrier of sodium ions, is favorable for the rapid diffusion of the sodium ions, and realizes the rapid charging and rapid discharging of the electrode material. In addition, the product has smaller crystal grains, so that gaps among the crystal grains are sufficient, deformation stress generated by embedding/releasing sodium ions is relieved, the circulation stability of the product is improved, and the nondestructive charging and discharging of the product are realized. Meanwhile, the material has larger specific surface area, can provide rich active energy storage sites and promotes the exertion of specific capacity of the material. In addition, the partial substitution of the transition metal ions further improves the reactivity of the material, thereby improving the rate capability of the material.
(2) The sodium ion battery anode material adopts the methods of low-temperature solvothermal, flash evaporation drying and low-temperature calcination in preparation, has simple and easy operation process, low energy consumption, material cost and equipment requirements, and is suitable for large-scale industrial production.
Drawings
FIG. 1 is a FESEM image of the positive electrode material prepared in example 1;
FIG. 2 is a FESEM image of the positive electrode material prepared in comparative example 1;
FIG. 3 is a graph showing the cycle performance of the positive electrode materials prepared in example 1 and comparative examples 1-2;
fig. 4 is a graph showing the ratio performance of the positive electrode materials prepared in example 1 and comparative examples 1-2.
Detailed Description
The present invention is described in detail below with reference to examples to facilitate understanding of the present invention by those skilled in the art. It is specifically pointed out that the examples are given solely for the purpose of illustration of the invention and are not to be construed as limiting the scope of the invention, since numerous insubstantial modifications and variations of the invention will be within the scope of the invention, as described above, will become apparent to those skilled in the art. Meanwhile, the raw materials mentioned below are not specified, and are all commercial products; the process steps or preparation methods not mentioned in detail are those known to the person skilled in the art.
Example 1
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material comprises the following steps:
(1) Respectively weighing 0.05mol of sodium bicarbonate, 0.1mol of ferrous sulfate, 0.1mol of manganese sulfate and 0.1mol of sodium sulfate, dispersing in 50 ml of water, and magnetically stirring until the sodium bicarbonate, the ferrous sulfate, the manganese sulfate and the sodium sulfate are completely dissolved to obtain a suspension;
(2) Placing the suspension prepared in the step (1) into a hydrothermal kettle with a lining volume of 80mL, and performing solvothermal reaction for 4 hours at 100 ℃; naturally cooling to room temperature, centrifuging, washing with ethanol and deionized water to obtain a primary product with water content of about 20%, and placing the primary product in a drying chamber with volume of 1m 3 Flash drying at 200deg.C and gas flow rate of 2m/s for 0.5h to obtain Na-based material 2 FeMn(SO 4 ) 3 Is a powder particle of (2);
(3) Calcining the powder particles prepared in the step (2) for 8 hours at 350 ℃ under the protection of argon atmosphere, wherein: the temperature rise rate is 1 ℃/min, and the Na of the embodiment is obtained 2 FeMn(SO 4 ) 3 And a positive electrode material.
Fig. 1 is a Field Emission Scanning Electron Microscope (FESEM) image of the cathode material prepared in example 1, and it can be seen from fig. 1 that the size of the prepared cathode material is relatively uniform, and the particle size is about 10-80nm.
Example 2
A positive electrode material has a chemical formula: na (Na) 3 Fe 0.5 Mn(SO 4 ) 3 . The preparation method of the positive electrode material is different from that of example 1 in that 0.1mol of ferric sulfate and 0.1mol of sodium sulfate used in step (1) are replaced by 0.05mol of ferric sulfate and 0.15Sodium sulfate was used in the same manner as in example 1.
Example 3
A positive electrode material has a chemical formula: naFeMn 1.5 (SO 4 ) 3 . The preparation method of the positive electrode material was different from that of example 1 in that 0.1mol of manganese sulfate, 0.1mol of sodium sulfate used in step (1) was replaced with 0.15mol of manganese sulfate, 0.05mol of sodium sulfate, and the rest was the same as in example 1.
Example 4
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material was different from that of example 1 in that 0.05mol of sodium bicarbonate used in step (1) was replaced with 0.05mol of sodium acetate, and the rest was the same as that of example 1.
Example 5
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the cathode material is different from that of example 1 in that 0.1mol of ferrous sulfate used in step (1) is replaced by 0.05mol of ferric sulfate, the dosage of sodium bicarbonate and sodium sulfate is changed to 0.15mol and 0.05mol respectively, and the rest is the same as example 1.
Example 6
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material is different from that of example 1 in that 0.1mol of ferrous sulfate and 0.1mol of manganese sulfate used in step (1) are replaced by 0.15mol of ferrous sulfate and 0.05mol of manganese sulfate, and the rest is the same as that of example 1.
Example 7
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material was different from that of example 1 in that 0.05mol of sodium bicarbonate and 0.1mol of sodium sulfate used in step (1) were replaced with 0.25mol of sodium bicarbonate and 0.1mol of ammonium sulfate, and the rest was the same as example 1.
Example 8
A positive electrode material has a chemical formula: na (Na) 3 FeMn 0.5 (SO 4 ) 3 . The method comprisesThe positive electrode material was prepared in the same manner as in example 1, except that 0.1mol of manganese sulfate, 0.1mol of sodium sulfate, and 0.05mol of manganese sulfate were used in the step (1) instead of 0.15mol of sodium sulfate.
Example 9
A positive electrode material has a chemical formula: na (Na) 2 Fe 1.5 Mn 0.5 (SO 4 ) 3 . The preparation method of the positive electrode material is different from that of example 1 in that 0.1mol of ferrous sulfate and 0.1mol of manganese sulfate used in step (1) are replaced by 0.15mol of ferrous sulfate and 0.05mol of manganese sulfate, and the rest is the same as that of example 1.
Example 10
A positive electrode material has a chemical formula: na (Na) 2 Fe 0.5 Mn 1.5 (SO 4 ) 3 . The preparation method of the positive electrode material is different from that of example 1 in that 0.1mol of ferrous sulfate and 0.1mol of manganese sulfate used in step (1) are replaced by 0.05mol of ferrous sulfate and 0.15mol of manganese sulfate, and the rest is the same as that of example 1.
Example 11
A positive electrode material has a chemical formula: na (Na) 2 FeNi(SO 4 ) 3 . The preparation method of the positive electrode material was different from that of example 1 in that 0.1mol of manganese sulfate used in step (1) was replaced with 0.1mol of nickel sulfate, and the rest was the same as in example 1.
Example 12
A positive electrode material has a chemical formula: na (Na) 2 FeNi(SO 4 ) 3 . The preparation method of the positive electrode material was different from that of example 1 in that 0.1mol of manganese sulfate used in step (1) was replaced with 0.1mol of nickel fluoride, and the rest was the same as in example 1.
Example 13
A positive electrode material has a chemical formula: na (Na) 2 FeNi(SO 4 ) 3 . The preparation method of the positive electrode material was different from that of example 1 in that 0.1mol of manganese sulfate used in step (1) was replaced with 0.1mol of nickel nitrate, and the rest was the same as in example 1.
Example 14
Positive electrodeThe material has a chemical formula: na (Na) 2 FeCo(SO 4 ) 3 . The positive electrode material was prepared in the same manner as in example 1, except that 0.1mol of manganese sulfate used in step (1) was 0.1mol of cobalt sulfate.
Example 15
A positive electrode material has a chemical formula: na (Na) 2 FeCo(SO 4 ) 3 . The positive electrode material was prepared in the same manner as in example 1, except that 0.1mol of manganese sulfate used in step (1) was 0.1mol of cobalt fluoride.
Example 16
A positive electrode material has a chemical formula: na (Na) 2 FeCo(SO 4 ) 3 . The preparation method of the positive electrode material was different from that of example 1 in that 0.1mol of manganese sulfate used in step (1) was 0.1mol of cobalt nitrate, and the rest was the same as in example 1.
Example 17
A positive electrode material has a chemical formula: na (Na) 2 FeZn(SO 4 ) 3 . The positive electrode material was prepared in the same manner as in example 1, except that 0.1mol of manganese sulfate used in step (1) was 0.1mol of zinc sulfate.
Example 18
A positive electrode material has a chemical formula: na (Na) 2 FeZn(SO 4 ) 3 . The positive electrode material was prepared in the same manner as in example 1, except that 0.1mol of zinc fluoride was used as 0.1mol of manganese sulfate in step (1).
Example 19
A positive electrode material has a chemical formula: na (Na) 2 FeZn(SO 4 ) 3 . The positive electrode material was prepared in the same manner as in example 1, except that 0.1mol of manganese sulfate used in step (1) was 0.1mol of zinc nitrate.
Example 20
A positive electrode material has a chemical formula: na (Na) 2 Fe 1.5 Mn 0.5 (SO 4 ) 3 . Preparation method of positive electrode materialThe process differs from example 1 in that in step (1) the sodium source: iron source: transition metal source: the sulfur source provided a molar ratio of 2.5:1.5:0.5:3, the specific raw materials were 0.05mol of sodium hydrogencarbonate, 0.15mol of ferrous sulfate, 0.05mol of manganese sulfate and 0.1mol of sodium sulfate, and the rest was the same as in example 1.
Example 21
A positive electrode material has a chemical formula: na (Na) 2 Fe 0.5 Mn 1.5 (SO 4 ) 3 . The preparation method of the positive electrode material is different from that of example 1 in that in step (1), a sodium source: iron source: transition metal source: the sulfur source provided a molar ratio of 2.5:0.5:1.5:3, the specific raw materials were 0.05mol of sodium hydrogencarbonate, 0.05mol of ferrous sulfate, 0.15mol of manganese sulfate and 0.1mol of sodium sulfate, and the rest was the same as in example 1.
Example 22
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material is different from that of example 1 in that the solvent used in step (2) is ethanol, and the rest is the same as that of example 1.
Example 23
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material is different from that of example 1 in that the solvothermal temperature used in step (2) is 40 ℃, and the rest is the same as example 1.
Example 24
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material was different from that of example 1 in that the solvothermal temperature used in step (2) was 80℃and the rest was the same as in example 1.
Example 25
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material is different from that of example 1 in that the solvothermal temperature used in step (2) is 160℃and the rest is the same as in example 1.
Example 26
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material is different from that of example 1 in that the solvothermal temperature used in step (2) is 220 ℃, and the rest is the same as that of example 1.
Example 27
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material is different from that of example 1 in that the solvothermal reaction time used in step (2) is 2h, and the rest is the same as example 1.
Example 28
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material is different from that of example 1 in that the solvothermal reaction time used in step (2) is 6 hours, and the rest is the same as example 1.
Example 29
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material is different from that of example 1 in that the solvothermal reaction time used in step (2) is 8 hours, and the rest is the same as example 1.
Example 30
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material is different from that of example 1 in that the solvothermal reaction time used in step (2) is 12 hours, and the rest is the same as example 1.
Example 31
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material is different from that of the example 1 in that the water content of the inlet material in the step (2) is 10%, and the rest is the same as the example 1.
Example 32
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material is different from example 1 in the steps of(2) The water content of the medium inlet material was 30%, and the rest was the same as in example 1.
Example 33
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material is different from example 1 in that the volume size of the drying chamber in the step (2) is 0.5m 3 The remainder was the same as in example 1.
Example 34
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material is different from example 1 in that the volume of the drying chamber in the step (2) is 2m 3 The remainder was the same as in example 1.
Example 35
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material was different from that of example 1 in that the drying chamber temperature in the step (2) was 120℃and the rest was the same as in example 1.
Example 36
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material was different from that of example 1 in that the drying chamber temperature in the step (2) was 150℃and the rest was the same as in example 1.
Example 37
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material was different from that of example 1 in that the drying chamber temperature in the drying chamber in the step (2) was 250℃and the rest was the same as in example 1.
Example 38
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material is different from that of example 1 in that the drying time in the step (2) is 0.2h, and the rest is the same as that of example 1.
Example 39
Positive electrode materialThe chemical formula of the material is as follows: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material is different from that of example 1 in that the drying time in step (2) is 1h, and the rest is the same as that of example 1.
Example 40
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material was different from that of example 1 in that the flow rate of the gas in the drying chamber in step (2) was 1m/s, and the rest was the same as in example 1.
Example 41
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material was different from that of example 1 in that the flow rate of the gas in the drying chamber in step (2) was 5m/s, and the rest was the same as in example 1.
Example 42
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material was different from that of example 1 in that the temperature of the calcination treatment in step (3) was 200℃and the rest was the same as in example 1.
Example 43
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material was different from that of example 1 in that the temperature of the calcination treatment in step (3) was 300℃and the rest was the same as in example 1.
Example 44
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material was different from that of example 1 in that the temperature of the calcination treatment in step (3) was 400℃and the rest was the same as in example 1.
Example 45
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material is different from example 1 in that the temperature rising rate of the calcination treatment in the step (3) is 0.5 ℃/min, whichThe remainder was the same as in example 1.
Example 46
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material was different from that of example 1 in that the temperature rise rate of the calcination treatment in step (3) was 2 ℃/min, and the rest was the same as in example 1.
Example 47
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material was different from that of example 1 in that the temperature rise rate of the calcination treatment in step (3) was 4 ℃/min, and the rest was the same as in example 1.
Example 48
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material was different from that of example 1 in that the calcination treatment time in step (3) was 2 hours, and the rest was the same as in example 1.
Example 49
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material was different from that of example 1 in that the calcination treatment time in step (3) was 24 hours, and the rest was the same as in example 1.
Example 50
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The preparation method of the positive electrode material was different from that of example 1 in that the calcination treatment time in step (3) was 48 hours, and the rest was the same as in example 1.
Example 51
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The method for producing the positive electrode material was different from example 1 in that the gas atmosphere for the calcination treatment in step (3) was nitrogen, and the remainder was the same as in example 1.
Example 52
A positive electrode material has a chemical formula: na (Na) 2 FeMn(SO 4 ) 3 . The method for producing the positive electrode material was different from example 1 in that the atmosphere of the calcination treatment in step (3) was a mixed gas of argon and hydrogen (volume ratio: 9.5:0.5), and the rest was the same as in example 1.
Example 53
A positive electrode active material of a sodium ion battery is the positive electrode material Na prepared in example 1 2 FeMn(SO 4 ) 3 . The preparation method of the sodium ion battery comprises the following steps:
(1) Preparing a battery anode: na is mixed with 2 FeMn(SO 4 ) 3 Adding powder, carbon black and polyvinylidene fluoride into proper amount of N-methyl pyrrolidone according to the mass ratio of 8:1:1, and fully grinding to obtain uniform slurry; then uniformly coating the slurry on the surface of an aluminum foil and then vacuum drying; cutting the electrode plate obtained by drying into a wafer with the diameter of 10mm, compacting and taking the wafer as a battery anode plate for standby;
(2) Preparing a battery cathode: pressing sodium metal into slices, cutting into wafers with the diameter of 12mm, and taking the wafers as a battery negative electrode plate for standby;
(3) And (3) battery assembly: and (3) using a glass fiber film as a diaphragm, dissolving 1M sodium hexafluorophosphate in a solvent of propylene carbonate and fluoroethylene carbonate (volume ratio of 95:5) to serve as electrolyte, sequentially and tightly stacking the battery positive electrode plate prepared in the step (1), the diaphragm and the battery negative electrode plate prepared in the step (2) in a glove box protected by inert gas, dripping the electrolyte to completely infiltrate the diaphragm, and then sealing the stacked part into a button cell casing to complete battery assembly.
Examples 54 to 104
The positive electrode materials used in the sodium-ion batteries of examples 54 to 104 correspond to the positive electrode materials prepared in examples 2 to 52, respectively, and the preparation method of each sodium-ion battery was the same as that of example 53.
Comparative example 1
A sodium ion battery was prepared as compared with example 53 in that, when preparing the positive electrode of the battery, the positive electrode material was changed to Na prepared by ball milling 2 FeMn(SO 4 ) 3 Positive electrode material particlesThe remainder was the same as in example 53. The preparation method comprises the following steps: drying 0.05mol of sodium bicarbonate, 0.1mol of ferrous sulfate, 0.1mol of manganese sulfate and 0.1mol of sodium sulfate, directly mixing, and ball-milling in a ball-milling tank for 12 hours to fully and uniformly mix all the powders; then transferring the ball-milled material into a magnetic boat, placing the magnetic boat in a tube furnace, calcining for 8 hours in an argon atmosphere at 350 ℃, heating at a speed of 1 ℃/min, and grinding after calcining to obtain Na 2 FeMn(SO 4 ) 3 Positive electrode material particles.
FIG. 2 is a FESEM image of a cathode material prepared by a ball milling method of comparative example 1. As can be seen from FIG. 2, na is prepared by a ball milling method 2 FeMn(SO 4 ) 3 The particle size of the positive electrode material is in the range of 1-5 mu m, the size is larger, and agglomeration is easy to occur, so that a block material is formed.
Comparative example 2
A sodium ion battery was prepared by a method differing from example 53 in that, when preparing a positive electrode, the positive electrode material was changed to Na 2 Fe 2 (SO 4 ) 3 The positive electrode material was the same as in example 53. Wherein Na is 2 Fe 2 (SO 4 ) 3 The positive electrode material was prepared in the same manner as in example 1 except that the ferrous sulfate was 0.2mol, and that manganese sulfate was not added.
Comparative example 3
A sodium ion battery was prepared by a method differing from example 53 in that, when preparing a positive electrode, the positive electrode material was changed to Na 2 Fe 2 (SO 4 ) 3 The positive electrode material was the same as in example 53. Wherein Na is 2 Fe 2 (SO 4 ) 3 The preparation method of the cathode material is different from that of example 1 in that ferrous sulfate is 0.2mol, manganese sulfate and sodium bicarbonate are not added, a solvent evaporation method is used in the drying process, and the mixed solution is dried under the magnetic force continuous stirring at 130 ℃; the remainder was the same as in example 1.
Comparative example 4
A sodium ion battery was prepared by a method differing from example 53 in that, when a positive electrode was prepared, the positive electrode was preparedMaterial change to Na 2 FeMn(SO 4 ) 3 The positive electrode material was the same as in example 53. Wherein Na is 2 FeMn(SO 4 ) 3 The preparation method of the cathode material is different from example 1 in that sodium bicarbonate is not added, a solvent evaporation method is used in the drying process, and the mixed solution is dried under magnetic force continuous stirring at 130 ℃. The remainder was the same as in example 1.
Comparative example 5
A sodium ion battery was prepared by a method differing from example 53 in that, when preparing a positive electrode, the positive electrode material was changed to Na 2 FeNi(SO 4 ) 3 The positive electrode material was the same as in example 53. Wherein Na is 2 FeNi(SO 4 ) 3 The positive electrode material was prepared by the method which was different from example 1 in that nickel sulfate was 0.1mol, manganese sulfate and sodium bicarbonate were not added, a solvent evaporation method was used in the drying process, and the mixed solution was dried at 130 ℃ with magnetic force under continuous stirring. The remainder was the same as in example 1.
Performance testing
The sodium ion batteries prepared in examples 53 to 104 and comparative examples 1 to 5 were subjected to performance tests in which: a BTSDA test system of Xinwei electronic Co Ltd in Shenzhen city is adopted for constant current charge and discharge test, the environment is a constant temperature and humidity room (25 ℃ and 35%), and the test voltage range is 2-4.5V. The cells were cycled 500 cycles at current densities of 1C and 10C, respectively, (1 c=120 mAh/g), with the test results shown in table 1.
Table 1: electrochemical performance test comparative tables of examples 53 to 104 and comparative examples 1 to 5
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As can be seen from table 1, the sodium ion batteries assembled from the positive electrode materials prepared in examples 1 to 52 of the present invention (examples 53 to 104) were more excellent in specific discharge capacity and rate properties than comparative examples 1 to 5.
Wherein: examples 2 to 10 use different molar ratios of Na, fe and S to Na source, iron source and sulfur source x Fe y Mn z (SO 4 ) 3 Positive electrode materials, examples 54 to 62 were sodium ion batteries assembled by using the positive electrodes obtained in examples 2 to 10, and found that ultra-small particles of Na obtained by reacting different sodium sources, iron sources, and sulfur sources x Fe y Mn z (SO 4 ) 3 The positive electrode material has little effect on the electrochemical performance of the battery because different types of sodium sources, iron sources and sulfur sources only provide sodium ions, iron ions and sulfate ions, and the rest of the ions do not participate in the reaction. While Na: fe: the S molar ratio has a certain influence on the product. When the sodium source ratio is too high or too low, the conversion rate and purity of the product are lowered, resulting in degradation of the cycle performance of the battery.
Examples 11 to 19 use of Na from different transition metal sources 2 Fe y M z (SO 4 ) 3 Positive electrode materials, examples 63-71 are sodium-ion batteries assembled with the positive electrode materials obtained in examples 11-19, and found that ultra-small particles of Na obtained by the reaction of different kinds of transition metals 2 Fe y M z (SO 4 ) 3 The positive electrode material has a certain influence on the electrochemical performance of the battery, and the capacity performance of a product generated by taking Fe and Ni as transition metal ions is superior to that of Co and Zn ions, because the reactivity of different ions and the chemical and coordination environments generated in the product are different, so that the electrochemical performance of the product is different. Different salt solutions of the same kind of transition metal ions have little effect on the electrochemical properties of the product, since the salt solutions only provide the transition metal ions required for the reaction, the remaining ions not taking part in the reaction.
Examples 20 to 21 are Na obtained by a molar ratio reaction of different sodium sources, iron sources, transition metal sources and sulfur sources 2 Fe y Mn z (SO 4 ) 3 Positive electrode material, examples 72-73 are sodium ion batteries assembled by using the positive electrode materials obtained in examples 20-21, and found that the sodium ion batteries are prepared by mixing sodium sources, iron sources, transition metal sources and sulfur sources to obtain ultra-small particles 2 Fe y Mn z (SO 4 ) 3 The cathode material has a certain influence on the electrochemical performance of the battery, and when the ratio of the transition metal ions is too high or too low, the cycle performance of the battery is reduced. As too high or too low a transition metal ion ratio will have an effect on the active energy storage sites of the product.
Example 22 is Na obtained by reaction with different solvents 2 FeMn(SO 4 ) 3 Positive electrode material, example 74 is a sodium-ion battery assembled with the positive electrode material obtained in example 13, and the ultra-small particles obtained by the reaction of different solvents were found to be Na 2 FeMn(SO 4 ) 3 The positive electrode material has a certain influence on the electrochemical performance of the battery, ethanol is used as a solvent, and the electrochemical performance of the product is drastically reduced. The reason is that the solubility of the reactant in the ethanol solvent is very low, the purity and conversion rate of the product are very low, and the performance of the product is affected.
Examples 23 to 26 are Na obtained by reactions at different hydrothermal temperatures 2 FeMn(SO 4 ) 3 Positive electrode materials, examples 75-78 are sodium-ion batteries assembled with the positive electrode materials obtained in examples 23-26, and were found to have ultra-small particles of Na obtained by different hydrothermal temperature reactions 2 FeMn(SO 4 ) 3 The cathode material has a certain influence on the electrochemical performance of the battery, when the hydrothermal temperature is too low at 40-80 ℃ or too high at 220 ℃, the cycle performance of the battery is reduced, and when the hydrothermal temperature is between 100-160 ℃, the electrochemical performance of the product is not greatly different. The reason is that at temperatures between 100-160 ℃, the provided growth environment already meets the growth requirements of the product. Too high or too low a hydrothermal temperature can easily cause damage to the crystalline form of the product.
Examples 27 to 30 are Na obtained by reactions with different hydrothermal reaction times 2 FeMn(SO 4 ) 3 Examples 79 to 82 are employed for the positive electrode material27-30, and found that the ultra-small particles obtained by different hydrothermal reaction time reactions are Na 2 FeMn(SO 4 ) 3 The positive electrode material has a certain influence on the electrochemical performance of the battery, when the reaction time is too low and is 2 hours, the cycle performance of the battery is reduced, and when the reaction time is 6-12 hours, the electrochemical performance of the battery is not greatly different. The reason is that the reaction time is insufficient, and the degree of progress of the reaction is insufficient.
Examples 31 to 32 are Na obtained by drying with different water contents of the inlet material 2 FeMn(SO 4 ) 3 Positive electrode materials, examples 83-84 are sodium ion batteries assembled by using the positive electrode materials obtained in examples 31-32, and the sodium ion batteries are prepared by finding ultra-small particles obtained by drying different inlet materials with water contents 2 FeMn(SO 4 ) 3 The positive electrode material has little influence on the electrochemical performance of the battery.
Examples 33-34 are Na obtained by drying with different drying chamber volumes 2 FeMn(SO 4 ) 3 Positive electrode materials, examples 85-86 are sodium ion batteries assembled using the positive electrode materials obtained in examples 33-34, and were found to be ultra-small particles of Na obtained by drying in different drying chamber volumes 2 FeMn(SO 4 ) 3 The positive electrode material has little influence on the electrochemical performance of the battery.
Examples 35-37 are Na obtained by drying at different drying chamber temperatures 2 FeMn(SO 4 ) 3 Positive electrode materials examples 87 to 89 were sodium ion batteries assembled using the positive electrode materials obtained in examples 35 to 37, and found that ultra-small particles of Na obtained by drying at different dry room temperatures 2 FeMn(SO 4 ) 3 The positive electrode material has little influence on the electrochemical performance of the battery.
Examples 38 to 39 are Na obtained by drying with different drying times 2 FeMn(SO 4 ) 3 Positive electrode materials, examples 90 to 91 are sodium ion batteries assembled using the positive electrode materials obtained in examples 38 to 39, and the ultra-small particles obtained by drying at different drying times were found to be Na 2 FeMn(SO 4 ) 3 The positive electrode material has little influence on the electrochemical performance of the battery.
Examples 40 to 41 are Na obtained by drying with different gas flow rates in the drying chamber 2 FeMn(SO 4 ) 3 Positive electrode materials, examples 92-93 were sodium ion batteries assembled using the positive electrode materials obtained in examples 40-41, and were found to be ultra-small particles of Na dried at different gas flow rates 2 FeMn(SO 4 ) 3 The positive electrode material has little influence on the electrochemical performance of the battery.
Examples 42-44 are Na obtained by reaction at different calcination treatment temperatures 2 FeMn(SO 4 ) 3 Positive electrode materials, examples 94-96 are sodium ion batteries assembled using the positive electrode materials obtained in examples 42-44, and were found to react at different calcination treatment temperatures to give ultra-small particles of Na 2 FeMn(SO 4 ) 3 The cathode material has a certain influence on the electrochemical performance of the battery, and the electrochemical performance of the product with lower calcination temperature is reduced. The reason is that the lower annealing temperature, the lower crystallization degree of the product and the unstable material structure.
Examples 45-47 are Na obtained by reactions with different heating rates 2 FeMn(SO 4 ) 3 Positive electrode materials, examples 97 to 99 were sodium ion batteries assembled using the positive electrode materials obtained in examples 45 to 47, and found that ultra-small particles of Na obtained by reaction at different heating rates 2 FeMn(SO 4 ) 3 The positive electrode material has little influence on the electrochemical performance of the battery.
Examples 48 to 50 are Na obtained by time reactions with different calcination treatments 2 FeMn(SO 4 ) 3 Positive electrode materials, examples 100-102 are sodium ion batteries assembled using the positive electrode materials obtained in examples 48-50, and the ultra-small particles obtained by the reaction at different calcination times were found to be Na 2 FeMn(SO 4 ) 3 The cathode material has a certain influence on the electrochemical performance of the battery, and the electrochemical performance of the product is reduced after shorter calcination time. The reason is that the shorter annealing time period leads to lower crystallization degree of the product and unstable structure.
Examples 51 to 52 are Na obtained by reaction in different calcination gas atmospheres 2 FeMn(SO 4 ) 3 Positive electrode materials, examples 103 to 104 were sodium ion batteries assembled using the positive electrode materials obtained in examples 51 to 52, and found that ultra-small particles of Na obtained by reaction in different calcined gas atmospheres 2 FeMn(SO 4 ) 3 The positive electrode material has little influence on the electrochemical performance of the battery.
Comparative example 1 is Na prepared by ball milling calcination 2 FeMn(SO 4 ) 3 As can be seen from FIG. 2, the positive electrode material of the positive sodium ion battery has larger particles, is easy to agglomerate, has low material utilization rate, and has lower discharge specific capacity and lower capacity retention rate after 500 circles of circulation.
Comparative example 2 is Na without transition metal substitution 2 Fe 2 (SO 4 ) 3 The positive electrode material can be seen to have lower initial coulombic efficiency and poorer capacity and cycle performance, because the transition metal substitution is probably lost, and the reactivity is reduced.
Comparative example 3 is Na prepared by solvent evaporation 2 Fe 2 (SO 4 ) 3 The positive electrode material has poor capacity and cycle performance, probably because grains are agglomerated in the reaction process to form secondary particles, and no transition metal is substituted, so that the reaction activity of the product is reduced.
Comparative example 4 is Na prepared by solvent evaporation 2 FeMn(SO 4 ) 3 The cathode material is poor in cycle performance, probably due to agglomeration of the electrode material during the reaction process, and secondary particles are formed.
Comparative example 5 is Na prepared by solvent evaporation 2 FeNi(SO 4 ) 3 The cathode material is poor in cycle performance, probably due to agglomeration of the electrode material during the reaction process, and secondary particles are formed.
FIG. 3 is a graph showing comparison of cycle performance of sodium iron sulfate-based cathode materials prepared by different methods of example 1 and comparative examples 1-2, as can be seen from FIG. 3, the ultra-small particles of Na prepared in example 1 2 FeMn(SO 4 ) 3 Non-destructive quick-charging positive electrode material with stable circulation performance and capacity retentionThe retention rate is higher. The sodium iron sulfate-based positive electrode material prepared in comparative examples 1-2 has poor cycle performance and low capacity retention rate.
FIG. 4 is a graph showing the comparison of the rate performance of the sodium iron sulfate-based cathode materials prepared in example 1 and comparative examples 1-2, as can be seen from FIG. 4, the ultra-small particles of Na prepared in example 1 2 FeMn(SO 4 ) 3 The lossless fast-charging positive electrode material has better cycle performance, high capacity retention rate and better multiplying power property under different current densities. The sodium iron sulfate-based positive electrode material prepared in comparative examples 1-2 has poor rate capability and low capacity retention rate.
It will be apparent to those skilled in the art that several simple deductions or substitutions may be made without departing from the inventive concept. Accordingly, it is intended that all such modifications as would be within the scope of this invention be included within the scope of this invention. The above embodiments are preferred embodiments of the present invention, and all similar processes and equivalent modifications are intended to fall within the scope of the present invention.

Claims (13)

1. A positive electrode material is characterized in that the molecular formula of the positive electrode material is Na x Fe y M z (SO 4 ) 3 Wherein x is more than or equal to 1.0 and less than or equal to 3.0,0.5, y is more than or equal to 2.0,0.5 and z is more than or equal to 1.5, and M is transition metal; the particle size of the positive electrode material is between 10 and 80 nm.
2. The positive electrode material according to claim 1, wherein the transition metal is selected from at least one of Sc, ti, V, cr, mn, co, ni, cu, zn, ag, pt, au, hg.
3. A method for preparing the positive electrode material according to claim 1 or 2, comprising the steps of:
(1) Dispersing a sodium source, an iron source, a transition metal source and a sulfur source in a solvent to obtain a suspension;
(2) Heating the suspension to perform solvothermal reaction; separating, washing and flash drying the product of the solvothermal reaction in sequence after cooling to obtain a Na-based catalyst x Fe y M z (SO 4 ) 3 Is a powder particle of (2);
(3) And calcining the powder particles under the protection of inert gas atmosphere to obtain the positive electrode material.
4. The method according to claim 3, wherein the sodium source is selected from the group consisting of sodium sulfate, sodium bisulfate, sodium carbonate, sodium bicarbonate, sodium acetate, sodium chloride, sodium phosphate, sodium nitrate, sodium phosphite, sodium formate, sodium propionate, sodium acrylate, sodium benzoate, sodium hypochlorite, sodium chlorate, sodium thiosulfate, sodium persulfate, sodium silicate, sodium bromate, sodium bromide, sodium iodide, sodium fluoride, sodium bisulfate, sodium nitrite, sodium oxalate, sodium persulfate, sodium hydroxide, sodium pyrosulfate, sodium dihydrogen phosphate, disodium hydrogen phosphate, sodium metabisulfite, sodium pyrophosphate, sodium hydrogen phthalate, sodium hydrogen oxalate, sodium sulfite, sodium sorbate, trisodium phosphate, sodium gluconate, sodium oleate, and hydrates of at least one of the foregoing;
And/or the iron source is selected from at least one of ferric sulfate, ferrous oxide, ferric chloride, ferric nitrate, ferric acetate, ferrous bromide, ferrous nitrate, ferrous phosphate, ferrous iodide, ferrous acetate, ferric metasilicate, ferric metatitanate, ferric disodium sulfate, ferric ammonium sulfate, ferrous carbonate, ferrous chloride, ferrous sulfate, ferrous hydroxide, ferric oxide, ferric trichloride, ferric hydroxide, and hydrates of the foregoing;
and/or the transition metal source is selected from soluble salts of scandium, titanium, vanadium, chromium, manganese, cobalt, nickel, copper, zinc, silver, platinum, gold, mercury and hydrates of at least one of the foregoing;
and/or the sulfur source is selected from at least one of ferric sulfate, ferrous sulfate, sodium bisulfate, potassium sulfate, ferric dithionite, ferric thiosulfate, ferric dithionite, sodium sulfate, sodium sulfite, sodium dithionite, sulfurous acid, sulfuric acid, ammonium persulfate, potassium persulfate, sodium dodecyl sulfate, sodium dodecyl benzene sulfonate and hydrates of the above.
5. The method for producing a positive electrode material according to claim 3 or 4, wherein the molar ratio of the sodium source, the iron source, the transition metal source and the sulfur source is (1-3): (0.5-2): (0.5-1.5): 3.
6. The method for producing a positive electrode material according to claim 3, wherein the solvent is at least one selected from the group consisting of water, methanol, ethanol, acetone, ethylene glycol, and pyridine.
7. The method for producing a positive electrode material according to claim 3, wherein in the step (2), the solvothermal reaction temperature is 40 to 220 ℃; and/or the solvothermal reaction time is 4-12h.
8. The method for producing a positive electrode material according to claim 3, wherein in the step (2), the flash drying temperature is 120 to 350 ℃; and/or the flash drying time is 0.2-6h.
9. The method for producing a positive electrode material according to claim 3, wherein in the step (3), the temperature of the calcination treatment is 200 to 400 ℃; and/or the calcination treatment is carried out for 2-48 hours.
10. The method according to claim 3, wherein in the step (3), the inert gas is at least one of a mixed gas of nitrogen, argon and hydrogen.
11. The positive pole piece of the sodium ion battery is characterized by comprising a current collector and a positive pole material layer coated on the surface of the current collector; the positive electrode material layer contains a positive electrode active material, and the positive electrode active material is the positive electrode material according to claim 1 or 2.
12. A sodium ion battery comprising the positive electrode sheet of the sodium ion battery of claim 11.
13. Use of the sodium ion battery of claim 12 in a mobile electronic communication device, an electric vehicle, an electric bicycle, an energy storage battery, a power battery or an energy storage power station.
CN202310700076.4A 2023-06-13 2023-06-13 Based on ultra-small particles Na x Fe y M z (SO 4 ) 3 Non-destructive quick-charging positive electrode material, and preparation method and application thereof Pending CN116706056A (en)

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