CN115196653B - Coated Prussian white and preparation method and application thereof - Google Patents
Coated Prussian white and preparation method and application thereof Download PDFInfo
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- CN115196653B CN115196653B CN202210914516.1A CN202210914516A CN115196653B CN 115196653 B CN115196653 B CN 115196653B CN 202210914516 A CN202210914516 A CN 202210914516A CN 115196653 B CN115196653 B CN 115196653B
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- prussian white
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- 238000002360 preparation method Methods 0.000 title claims abstract description 34
- 238000005406 washing Methods 0.000 claims abstract description 79
- 239000011734 sodium Substances 0.000 claims abstract description 56
- 239000000126 substance Substances 0.000 claims abstract description 55
- 239000012266 salt solution Substances 0.000 claims abstract description 45
- XAEFZNCEHLXOMS-UHFFFAOYSA-M potassium benzoate Chemical compound [K+].[O-]C(=O)C1=CC=CC=C1 XAEFZNCEHLXOMS-UHFFFAOYSA-M 0.000 claims abstract description 31
- 229910001415 sodium ion Inorganic materials 0.000 claims abstract description 29
- 229910001414 potassium ion Inorganic materials 0.000 claims abstract description 19
- FKNQFGJONOIPTF-UHFFFAOYSA-N Sodium cation Chemical compound [Na+] FKNQFGJONOIPTF-UHFFFAOYSA-N 0.000 claims abstract description 12
- 230000009471 action Effects 0.000 claims abstract description 8
- 238000000576 coating method Methods 0.000 claims description 42
- 239000011248 coating agent Substances 0.000 claims description 39
- OTYBMLCTZGSZBG-UHFFFAOYSA-L potassium sulfate Chemical compound [K+].[K+].[O-]S([O-])(=O)=O OTYBMLCTZGSZBG-UHFFFAOYSA-L 0.000 claims description 37
- 229910052939 potassium sulfate Inorganic materials 0.000 claims description 30
- 235000011151 potassium sulphates Nutrition 0.000 claims description 30
- 238000001035 drying Methods 0.000 claims description 29
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 claims description 21
- FGIUAXJPYTZDNR-UHFFFAOYSA-N potassium nitrate Chemical compound [K+].[O-][N+]([O-])=O FGIUAXJPYTZDNR-UHFFFAOYSA-N 0.000 claims description 12
- 239000001103 potassium chloride Substances 0.000 claims description 11
- 235000011164 potassium chloride Nutrition 0.000 claims description 11
- 235000010333 potassium nitrate Nutrition 0.000 claims description 6
- 239000004323 potassium nitrate Substances 0.000 claims description 6
- 239000001508 potassium citrate Substances 0.000 claims description 2
- 229960002635 potassium citrate Drugs 0.000 claims description 2
- QEEAPRPFLLJWCF-UHFFFAOYSA-K potassium citrate (anhydrous) Chemical compound [K+].[K+].[K+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O QEEAPRPFLLJWCF-UHFFFAOYSA-K 0.000 claims description 2
- 235000011082 potassium citrates Nutrition 0.000 claims description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 47
- 238000000034 method Methods 0.000 abstract description 16
- 241000046198 Triteleia hyacinthina Species 0.000 abstract description 3
- 238000004146 energy storage Methods 0.000 abstract description 3
- 239000000243 solution Substances 0.000 description 126
- 238000006243 chemical reaction Methods 0.000 description 88
- 239000012065 filter cake Substances 0.000 description 64
- 239000002002 slurry Substances 0.000 description 47
- 239000011247 coating layer Substances 0.000 description 40
- 239000000463 material Substances 0.000 description 40
- 239000001509 sodium citrate Substances 0.000 description 34
- NLJMYIDDQXHKNR-UHFFFAOYSA-K sodium citrate Chemical compound O.O.[Na+].[Na+].[Na+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O NLJMYIDDQXHKNR-UHFFFAOYSA-K 0.000 description 34
- 239000000264 sodium ferrocyanide Substances 0.000 description 34
- 235000012247 sodium ferrocyanide Nutrition 0.000 description 34
- GTSHREYGKSITGK-UHFFFAOYSA-N sodium ferrocyanide Chemical compound [Na+].[Na+].[Na+].[Na+].[Fe+2].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-] GTSHREYGKSITGK-UHFFFAOYSA-N 0.000 description 34
- 229940099596 manganese sulfate Drugs 0.000 description 27
- 239000011702 manganese sulphate Substances 0.000 description 27
- 235000007079 manganese sulphate Nutrition 0.000 description 27
- SQQMAOCOWKFBNP-UHFFFAOYSA-L manganese(II) sulfate Chemical compound [Mn+2].[O-]S([O-])(=O)=O SQQMAOCOWKFBNP-UHFFFAOYSA-L 0.000 description 27
- 239000000047 product Substances 0.000 description 25
- 238000003756 stirring Methods 0.000 description 23
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 22
- 230000000052 comparative effect Effects 0.000 description 17
- 230000032683 aging Effects 0.000 description 16
- 238000001914 filtration Methods 0.000 description 15
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 14
- 229910052708 sodium Inorganic materials 0.000 description 14
- 239000012535 impurity Substances 0.000 description 12
- 238000007254 oxidation reaction Methods 0.000 description 12
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 11
- 239000012452 mother liquor Substances 0.000 description 11
- 229910052757 nitrogen Inorganic materials 0.000 description 11
- 229910052700 potassium Inorganic materials 0.000 description 11
- 229960003975 potassium Drugs 0.000 description 11
- 239000011591 potassium Substances 0.000 description 11
- 238000001556 precipitation Methods 0.000 description 11
- 238000005086 pumping Methods 0.000 description 11
- 239000012792 core layer Substances 0.000 description 10
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 9
- 230000000694 effects Effects 0.000 description 6
- 229910052751 metal Inorganic materials 0.000 description 6
- 239000002184 metal Substances 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- 238000001878 scanning electron micrograph Methods 0.000 description 6
- 238000010521 absorption reaction Methods 0.000 description 5
- 239000008139 complexing agent Substances 0.000 description 5
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 5
- 239000007774 positive electrode material Substances 0.000 description 5
- 229910003321 CoFe Inorganic materials 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 3
- 229940044175 cobalt sulfate Drugs 0.000 description 3
- 229910000361 cobalt sulfate Inorganic materials 0.000 description 3
- KTVIXTQDYHMGHF-UHFFFAOYSA-L cobalt(2+) sulfate Chemical compound [Co+2].[O-]S([O-])(=O)=O KTVIXTQDYHMGHF-UHFFFAOYSA-L 0.000 description 3
- 239000003792 electrolyte Substances 0.000 description 3
- 239000011790 ferrous sulphate Substances 0.000 description 3
- 235000003891 ferrous sulphate Nutrition 0.000 description 3
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 3
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 3
- 239000011572 manganese Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000003786 synthesis reaction Methods 0.000 description 3
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 description 2
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 2
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 description 2
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 2
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 229910017052 cobalt Inorganic materials 0.000 description 2
- 239000010941 cobalt Substances 0.000 description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000006731 degradation reaction Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- 229910001416 lithium ion Inorganic materials 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 238000004537 pulping Methods 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- KCXVZYZYPLLWCC-UHFFFAOYSA-N EDTA Chemical compound OC(=O)CN(CC(O)=O)CCN(CC(O)=O)CC(O)=O KCXVZYZYPLLWCC-UHFFFAOYSA-N 0.000 description 1
- 240000002624 Mespilus germanica Species 0.000 description 1
- 235000017784 Mespilus germanica Nutrition 0.000 description 1
- 235000000560 Mimusops elengi Nutrition 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- OFOBLEOULBTSOW-UHFFFAOYSA-N Propanedioic acid Natural products OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 1
- KEAYESYHFKHZAL-UHFFFAOYSA-N Sodium Chemical compound [Na] KEAYESYHFKHZAL-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 235000007837 Vangueria infausta Nutrition 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- 239000010405 anode material Substances 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000010406 cathode material Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 description 1
- 229910052808 lithium carbonate Inorganic materials 0.000 description 1
- VZCYOOQTPOCHFL-UPHRSURJSA-N maleic acid Chemical compound OC(=O)\C=C/C(O)=O VZCYOOQTPOCHFL-UPHRSURJSA-N 0.000 description 1
- 239000011976 maleic acid Substances 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000002715 modification method Methods 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 239000002345 surface coating layer Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- VZCYOOQTPOCHFL-UHFFFAOYSA-N trans-butenedioic acid Natural products OC(=O)C=CC(O)=O VZCYOOQTPOCHFL-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
- C01C3/00—Cyanogen; Compounds thereof
- C01C3/08—Simple or complex cyanides of metals
- C01C3/12—Simple or complex iron cyanides
-
- 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
- H01M4/36—Selection of substances as active materials, active masses, active liquids
-
- 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
- H01M4/362—Composites
- H01M4/366—Composites as layered products
-
- 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
-
- 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
- C01P2004/80—Particles consisting of a mixture of two or more inorganic phases
- C01P2004/82—Particles consisting of a mixture of two or more inorganic phases two phases having the same anion, e.g. both oxidic phases
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/40—Electric properties
-
- 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
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Toxicology (AREA)
- General Health & Medical Sciences (AREA)
- Inorganic Chemistry (AREA)
- Organic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Composite Materials (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
The invention belongs to the technical field of novel energy storage batteries, and discloses a coated Prussian white hyacinth and a preparation method and application thereof. The chemical formula of the coated Prussian white is K x Na 2‑x AFe(CN) 6 Is represented by the chemical formula Na 2 AFe(CN) 6 The inner core and the chemical formula of (C) are K 2 AFe(CN) 6 Wherein x=0.06-0.6, a is Ni 2+ 、Co 2+ 、Mn 2+ Or Fe (Fe) 2+ At least one of them. The preparation method comprises washing Prussian white with potassium salt solution under the action of centrifugal force to replace at least part of sodium ions on the surface with potassium ions; the rotation frequency for generating centrifugal force is 10-60Hz. The coated Prussian white provided by the invention can reduce the water absorbability of the Prussian white, and can also greatly improve the rate capability of a sodium ion battery prepared by using the coated Prussian white; the preparation method is simple in preparation procedure and can greatly shorten the preparation time.
Description
Technical Field
The invention belongs to the technical field of novel energy storage batteries, and particularly relates to a coated Prussian white hyacinth and a preparation method and application thereof.
Background
As the price of lithium carbonate increases, the profit of lithium ion batteries is greatly compressed. Compared with the lithium ion positive electrode material, the sodium ion positive electrode material has lower manufacturing cost. Sodium is a common element in sodium cathode materials, which leads to significant reduction in manufacturing costs of the materials, and is increasingly favored in the energy storage industry. As one of the sodium ion positive electrode materials, prussian white has stronger water absorption, and has great influence on the cycle performance and the rate performance of the battery core, so that the reduction of the water content and the water absorption of the material has important significance.
Coating is a common material modification method, and more methods for coating Prussian white exist at present. The conventional coating reaction is generally to prepare a material to be coated through the procedures of liquid phase synthesis, filtration, washing, drying and the like, then the material to be coated is put back into a reaction kettle, water is added for pulping, a coating agent is added into the kettle for coating reaction, and the second filtering, washing and drying procedures are carried out to obtain a coated modified product. The whole process flow is tedious, the steps are repeated, the time is too long, and the loss rate is high. In some coating methods, in order to reduce the procedures and improve the yield, slurry containing a substance to be coated prepared by liquid phase synthesis reaction is left in a reaction kettle, a certain temperature is kept and stirred, and then a coating agent is added for reaction, so that the required coating modified material can be obtained only through one-time filtration, washing and drying procedures. However, this method has many drawbacks, such as that the slurry prepared by the synthesis reaction contains a large amount of salt impurities, which interfere with the coating reaction, thereby affecting the product performance. If the Prussian white is coated by the method, the purity of the Prussian white is necessarily influenced, and therefore the performance of the sodium ion battery is influenced.
Therefore, it is desirable to provide a coated Prussian white material, which has a simple preparation process, can greatly shorten the preparation time, and can improve the performance of a sodium ion battery.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems in the prior art described above. Therefore, the invention provides a coated Prussian white hyacinth and a preparation method and application thereof. The coated Prussian white provided by the invention can reduce the water absorbability of the Prussian white and improve the performance of a sodium ion battery; and the preparation process is simple, and the preparation time can be greatly shortened.
The first aspect of the invention provides coated Prussian white.
Specifically, a coated Prussian white with a chemical formula of K x Na 2-x AFe(CN) 6 The coating Prussian white has a chemical formula of Na 2 AFe(CN) 6 The inner core and the chemical formula of (C) are K 2 AFe(CN) 6 Wherein x=0.06-0.6, a is Ni 2+ 、Co 2+ 、Mn 2+ 、Fe 2+ At least one of them.
Preferably, in the formula, x=0.06 to 0.3.
Preferably, the coated Prussian white is prepared by washing Prussian white with a potassium salt solution under the action of centrifugal force to replace at least part of sodium ions on the surface of the Prussian white with potassium ions.
The second aspect of the invention provides a preparation method of coated Prussian white.
Specifically, the preparation method of the coated Prussian white comprises the following steps:
under the action of centrifugal force, washing Prussian white by adopting a potassium salt solution to replace at least part of sodium ions on the surface of the Prussian white by potassium ions; then washing and drying to obtain coated Prussian white; the rotation frequency for generating the centrifugal force is 10-60Hz.
Preferably, the rotational frequency at which the centrifugal force is generated is 15-50Hz; it is further preferred that the rotational frequency at which the centrifugal force is generated is 20-40Hz. Experiments find that when the Prussian white is washed by adopting a potassium salt solution, the control of centrifugal force is one of important factors influencing the coating effect. When the rotation frequency is too low during washing, the potassium salt solution is not enough in centrifugal force, so that Prussian white is difficult to infiltrate; the rotating frequency during washing is too high, namely the rotating speed is too high, the centrifugal effect is too strong, the potassium salt solution is easy to be quickly thrown away from the equipment, the contact time with Prussian white is too short, and a good coating effect cannot be achieved.
It will be appreciated that the apparatus for generating the centrifugal force is not limited and that centrifuges are commonly used in this process. The centrifugal machine can not only finish the process of washing Prussian white, but also carry out the subsequent water washing process, reduce the transfer times of materials and simplify the preparation process.
Preferably, the potassium salt in the potassium salt solution is at least one of potassium sulfate, potassium nitrate, potassium chloride or potassium citrate.
Preferably, the concentration of the potassium salt solution is 0.3-3mol/L; further, the concentration of the potassium salt solution is 0.5-2mol/L.
Preferably, the amount of the substance of the potassium salt solution is 20% -100% of the amount of the substance of Prussian white. Such as 20%, 25%, 30%, 35%, 40%, 50%, 60%, 70%, 80%, 90%.
Preferably, the washing time is 2-15 minutes; more preferably, the washing time is 5 to 10 minutes. The Prussian white is washed by adopting the potassium salt solution, and the degradation of the coating layer can be effectively prevented by controlling the washing time. After the potassium salt solution is added into Prussian white, almost complete reaction can be achieved within a few minutes, and after the reaction, good coating effect can be achieved through short aging (namely, the washing process comprises the reaction and the aging process). If the washing time is too long, potassium ions originally positioned on the surface coating layer of the material can migrate and diffuse into the material under the condition of aqueous solution, so that the coating layer is degraded, more holes appear on the surface of the material, and after the material is used for preparing a battery, the contact area of the material and electrolyte is increased, and the stability is reduced.
Preferably, the drying temperature is 150-180 ℃.
It can be appreciated that the Prussian white can be a directly purchased product or a product prepared by a conventional method.
Preferably, the Prussian white is prepared by the following method:
mixing a ferrocyanide salt solution, a metal salt solution and a complexing agent solution in a protective gas atmosphere, reacting at 40-95 ℃, aging the slurry obtained by the reaction for 6-48 hours, and centrifugally separating to remove the separation liquid to obtain the Prussian white.
Preferably, the concentration of the sodium ferrocyanide solution is 0.3-0.6mol/L.
Preferably, the metal salt in the metal salt solution is one or more of sulfate, nitrate, acetate and chloride of nickel, cobalt, manganese and ferrous.
Preferably, the concentration of the metal salt solution is 0.5-2mol/L.
Preferably, the reaction pH is controlled to be 6.5 to 9.5 when the reaction is carried out.
Preferably, the complexing agent is at least one of citric acid, maleic acid, medlar acid, ethylenediamine tetraacetic acid, sodium citrate and ammonia water.
Preferably, the complexing agent solution has a concentration of 0.5-5mol/L.
More specifically, the preparation method of the coated Prussian white comprises the following steps:
(1) Preparing a ferrocyanide salt solution, a metal salt solution and a complexing agent solution, introducing protective gas into a reaction kettle to prevent oxidization, increasing the temperature to 40-95 ℃, adding the ferrocyanide salt solution, the metal salt solution and the complexing agent solution into the reaction kettle, reacting, controlling the addition amount of the ferrocyanide salt solution, keeping the pH value at 6.5-9.5 during the reaction, aging the reacted slurry for 6-48 hours, and centrifuging to separate the separated liquid to obtain Prussian white;
(2) Placing the Prussian white in a centrifugal machine, controlling the rotation frequency of the centrifugal machine to be 10-60Hz, washing the Prussian white by adopting a potassium salt solution, enabling potassium ions to partially replace sodium ions on the surface of the Prussian white to form a coating layer, washing the Prussian white by water to remove impurities, and drying the Prussian white at 150-180 ℃ to obtain the coated Prussian white.
The third aspect of the invention provides an application of coated Prussian white.
Specifically, the coated Prussian white is applied to the preparation of a battery anode material.
A positive electrode sheet comprises the coated Prussian white.
In a fourth aspect, the invention provides a sodium ion battery.
Specifically, the sodium ion battery comprises the positive plate.
Preferably, the battery positive electrode material is a sodium ion battery positive electrode material.
According to the technical scheme provided by the invention, the potassium salt solution is adopted to wash the Prussian white under the action of centrifugal force, and when the potassium salt solution flows through the Prussian white, the potassium salt system Prussian white is K SP The potassium ions in the solution can partially replace sodium ions on the Prussian white surface (the actual utilization rate of potassium salt is 10% -30%, and finally potassium replaces 3% -30% of the sodium in Prussian white), a coating layer is formed on the material surface, and the structure of a material inner core is Na 2 AFe(CN) 6 The coating layer structure is K 2 AFe(CN) 6 A is one or more of nickel, cobalt, manganese and ferrous iron. In addition, a small amount of attachments are formed on the surface of the material, and the material is recrystallized after being dissolved, so that the structure of the material is consistent with that of the coating layer. On one hand, the radius of K ions is slightly larger than that of Na ions, and when K replaces Na, the lattice of the material is distorted, and the distance and the channel are reduced. When the uncoated Prussian white is taken out after being dried, the water in the air is easily absorbed, so that the water content of the product is higher; the water absorption of the material is greatly reduced when the material is dried and taken out, and the water content of the obtained product is obviously reduced. On the other hand, due to the existence of the coating layer, the structural stability of the material in the charge and discharge process can be effectively improved, the side reaction with electrolyte is reduced, the interface stability and the cycle performance are improved, the multiplying power performance of the material is also greatly improved, and the specific capacity of the material at high multiplying power is almost 2 times that of the uncoated material.
Compared with the prior art, the invention has the following beneficial effects:
(1) The invention washes Prussian white by adopting potassium salt solution under the action of centrifugal force, and well coats the Prussian white by controlling the rotation frequency and washing time for generating centrifugal force, and forms the inner core as Na 2 AFe(CN) 6 The coating layer is K 2 AFe(CN) 6 Is coated with Prussian white. The coating mode enables the lattice of the material to be distorted, the space and the channels to be reduced, the water absorption of Prussian white can be effectively reduced, and the stability of the battery material is improved; meanwhile, the rate performance of the sodium ion battery prepared by the method can be greatly improved, and the specific capacity of the battery (5C) at high rate is almost 2 times that of the battery without the coating material.
(2) The preparation method provided by the invention can also effectively avoid migration and diffusion of potassium ions in the coating layer to the interior of Prussian white, so that more holes appear on the surface of the material, the degradation risk of the coating layer is reduced, and the stability of the material is improved.
(3) The invention adopts the sylvite solution to wash Prussian white under the action of centrifugal force, and the coating process can be completed in a centrifugal machine, namely, in the normal washing step, the step of washing the sylvite solution is inserted, and the step of washing the sylvite solution is not required to be completed in a reaction kettle, so that the material transfer times are reduced, the preparation process is simplified, the preparation time is shortened, the manpower and material resources are greatly saved, and the production cost is reduced.
Drawings
Fig. 1 is a process flow diagram of the preparation of coated Prussian white of example 1;
fig. 2 is an SEM image of coated prussian white prepared in example 1;
fig. 3 is an SEM image of prussian white prepared in comparative example 1;
fig. 4 is an SEM image of coated prussian white prepared in comparative example 2.
Detailed Description
In order to make the technical solutions of the present invention more apparent to those skilled in the art, the following examples will be presented. It should be noted that the following examples do not limit the scope of the invention.
The starting materials, reagents or apparatus used in the following examples are all available from conventional commercial sources or may be obtained by methods known in the art unless otherwise specified.
Example 1
Coated Prussian white with a chemical formula of K 0.2 Na 1.8 MnFe(CN) 6 Comprises an inner core layer and a coating layer, wherein the inner core has a chemical formula of Na 2 MnFe(CN) 6 The chemical formula of the coating layer is K 2 MnFe(CN) 6 。
The preparation method of the coated Prussian white comprises the following steps:
(1) Prussian white was synthesized: 0.5mol/L sodium ferrocyanide solution, 1.6mol/L manganese sulfate solution and 2mol/L sodium citrate solution are prepared. Adding a proper amount of pure water into a reaction kettle, reaching the position of a stirring paddle, starting stirring, then introducing nitrogen into the reaction kettle to prevent oxidization, then raising the temperature to 65 ℃, and simultaneously pumping a sodium ferrocyanide solution, a manganese sulfate solution and a sodium citrate solution into the reaction kettle by using a metering pump, wherein the flow rate of the sodium citrate solution is 1.2 times that of the manganese sulfate solution. The solution is subjected to precipitation reaction in a reaction kettle, the flow of sodium ferrocyanide is controlled, the reaction pH is kept at 8.5, and the reacted slurry is aged for 18 hours. And leading the Prussian white slurry in the aging tank to a centrifugal machine for filtering, removing mother liquor in the slurry, and leaving a filter cake in the centrifugal machine.
(2) Coating Prussian white: and (3) keeping the centrifuge rotating at 20Hz, and then introducing 0.5mol/L potassium sulfate salt solution into the centrifuge to wash the filter cake, wherein the consumption of potassium sulfate is 50% of that of Prussian Bai Maer in the centrifuge, and calculating the flow of the potassium sulfate solution to enable the time for washing the Prussian white filter cake to be 8 minutes, and the potassium ions partially replace sodium ions on the Prussian white surface to form a coating layer. The coating utilization of potassium sulfate was tested to be about 20% with potassium replacing about 10% of the sodium.
(3) Washing and drying: and (3) continuously washing the filter cake which is coated by washing the potassium salt solution in the centrifugal machine by pure water to remove impurities in the filter cake, wherein the volume of washing water is 0.4 times that of the aged slurry. Drying the filter cake at 180deg.C to obtain coated Prussian white product with chemical formulaFor K 0.2 Na 1.8 MnFe(CN) 6 。
The process flow chart of the preparation method is shown in figure 1.
Example 2
Coated Prussian white with a chemical formula of K 0.1 Na 1.9 MnFe(CN) 6 Comprises an inner core layer and a coating layer, wherein the inner core has a chemical formula of Na 2 MnFe(CN) 6 The chemical formula of the coating layer is K 2 MnFe(CN) 6 。
The preparation method of the coated Prussian white comprises the following steps:
(1) Prussian white was synthesized: preparing 0.4mol/L sodium ferrocyanide solution, 2mol/L manganese sulfate solution and 2mol/L sodium citrate solution. Adding a proper amount of pure water into a reaction kettle, reaching the position of a stirring paddle, starting stirring, then introducing nitrogen into the reaction kettle to prevent oxidization, then raising the temperature to 75 ℃, and simultaneously pumping a sodium ferrocyanide solution, a manganese sulfate solution and a sodium citrate solution into the reaction kettle by using a metering pump, wherein the flow rate of the sodium citrate solution is 2 times that of the manganese sulfate solution. The solution is subjected to precipitation reaction in a reaction kettle, the flow of sodium ferrocyanide is controlled, the reaction pH is kept at 8.2, and the reacted slurry is aged for 12 hours. And leading the Prussian white slurry in the aging tank to a centrifugal machine for filtering, removing mother liquor in the slurry, and leaving a filter cake in the centrifugal machine.
(2) Coating Prussian white: and (3) keeping the centrifuge rotating at 20Hz, and then introducing 0.5mol/L potassium sulfate salt solution into the centrifuge to wash the filter cake, wherein the consumption of potassium sulfate is 25% of that of Prussian Bai Maer in the centrifuge, and calculating the flow of the potassium sulfate solution to enable the time for washing the Prussian white filter cake to be 6 minutes, and the potassium ions partially replace sodium ions on the Prussian white surface to form a coating layer. The coating utilization of potassium sulfate was tested to be about 20% with potassium replacing about 5% of the sodium.
(3) Washing and drying: and (3) continuously washing the filter cake which is coated by washing with the potassium sulfate solution in the centrifugal machine by using pure water to remove impurities in the filter cake, wherein the volume of washing water is 0.4 times that of the aged slurry. Drying the filter cake at 180 ℃ to obtain coated Prussian whiteThe chemical formula of the product is K 0.1 Na 1.9 MnFe(CN) 6 。
Example 3
Coated Prussian white with a chemical formula of K 0.08 Na 1.92 Fe[Fe(CN) 6 ]Comprises an inner core layer and a coating layer, wherein the inner core has a chemical formula of Na 2 Fe[Fe(CN) 6 ]The chemical formula of the coating layer is K 2 Fe[Fe(CN) 6 ]。
The preparation method of the coated Prussian white comprises the following steps:
(1) Prussian white was synthesized: preparing 0.5mol/L sodium ferrocyanide solution, 1.5mol/L ferrous sulfate solution and 2mol/L sodium citrate solution. Adding a proper amount of pure water into a reaction kettle, reaching the position of a stirring paddle, starting stirring, then introducing nitrogen into the reaction kettle to prevent oxidization, then raising the temperature to 75 ℃, and simultaneously pumping sodium ferrocyanide solution, ferrous sulfate solution and sodium citrate solution into the reaction kettle by using a metering pump, wherein the flow rate of the sodium citrate solution is 1.5 times that of the ferrous sulfate solution. The solution is subjected to precipitation reaction in a reaction kettle, the flow of sodium ferrocyanide is controlled, the reaction pH is kept at 8.1, and the reacted slurry is aged for 12 hours. And leading the Prussian white slurry in the aging tank to a centrifugal machine for filtering, removing mother liquor in the slurry, and leaving a filter cake in the centrifugal machine.
(2) Coating Prussian white: and (3) keeping the centrifuge to rotate at 30Hz, introducing 2mol/L potassium chloride salt solution into the centrifuge to wash the filter cake, wherein the consumption of potassium chloride is 60% of that of Prussian Bai Maer in the centrifuge, calculating the flow of the potassium chloride solution, and enabling the time for washing the Prussian white filter cake to be 5 minutes, wherein potassium ions partially replace sodium ions on the Prussian white surface, so as to form a coating layer. The coating utilization of potassium chloride was tested to be about 13% with potassium replacing about 4% of the sodium.
(3) Washing and drying: and (3) continuously washing the filter cake which is coated by washing with the potassium chloride solution in the centrifugal machine by using pure water to remove impurities in the filter cake, wherein the volume of washing water is 0.5 times that of the aged slurry. Drying the filter cake at 180deg.C to obtain coated Prussian white product with chemical formula of K 0.08 Na 1.92 Fe[Fe(CN) 6 ]。
Example 4
Coated Prussian white with a chemical formula of K 0.08 Na 1.92 CoFe(CN) 6 Comprises an inner core layer and a coating layer, wherein the inner core has a chemical formula of Na 2 CoFe(CN) 6 The chemical formula of the coating layer is K 2 CoFe(CN) 6 。
The preparation method of the coated Prussian white comprises the following steps:
(1) Prussian white was synthesized: preparing 0.4mol/L sodium ferrocyanide solution, 2mol/L cobalt sulfate solution and 2mol/L sodium citrate solution. Adding a proper amount of pure water into a reaction kettle, reaching the position of a stirring paddle, starting stirring, then introducing nitrogen into the reaction kettle to prevent oxidization, then raising the temperature to 85 ℃, and simultaneously pumping a sodium ferrocyanide solution, a cobalt sulfate solution and a sodium citrate solution into the reaction kettle by using a metering pump, wherein the flow rate of the sodium citrate solution is 2 times that of the cobalt sulfate solution. The solution is subjected to precipitation reaction in a reaction kettle, the flow of sodium ferrocyanide is controlled, the reaction pH is kept at 8.0, and the reacted material is aged for 18 hours. And leading the Prussian white slurry in the aging tank to a centrifugal machine for filtering, removing mother liquor in the slurry, and leaving a filter cake in the centrifugal machine.
(2) Coating Prussian white: and (3) keeping the centrifuge to rotate at 30Hz, introducing 2mol/L potassium chloride salt solution into the centrifuge to wash the filter cake, wherein the consumption of potassium chloride is 60% of that of Prussian Bai Maer in the centrifuge, calculating the flow of the potassium sulfate solution, and enabling the time for washing the Prussian white filter cake to be 5 minutes, wherein potassium ions partially replace sodium ions on the Prussian white surface to form a coating layer. The coating utilization of potassium sulfate was tested to be about 13% with potassium replacing about 4% of the sodium.
(3) Washing and drying: and (3) continuously washing the filter cake which is coated by washing with the potassium chloride solution in the centrifugal machine by using pure water to remove impurities in the filter cake, wherein the volume of washing water is 0.5 times that of the aged slurry. Drying the filter cake at 180deg.C to obtain coated Prussian white product with chemical formula of K 0.08 Na 1.92 CoFe(CN) 6 。
Example 5
Coated Prussian white with a chemical formula of K 0.1 Na 1.9 MnFe(CN) 6 Comprises an inner core layer and a coating layer, wherein the inner core has a chemical formula of Na 2 MnFe(CN) 6 The chemical formula of the coating layer is K 2 MnFe(CN) 6 。
The preparation method of the coated Prussian white comprises the following steps:
(1) Prussian white was synthesized: preparing 0.4mol/L sodium ferrocyanide solution, 2mol/L manganese sulfate solution and 2mol/L sodium citrate solution. Adding a proper amount of pure water into a reaction kettle, reaching the position of a stirring paddle, starting stirring, then introducing nitrogen into the reaction kettle to prevent oxidization, then raising the temperature to 75 ℃, and simultaneously pumping a sodium ferrocyanide solution, a manganese sulfate solution and a sodium citrate solution into the reaction kettle by using a metering pump, wherein the flow rate of the sodium citrate solution is 1.5 times that of the manganese sulfate solution. The solution is subjected to precipitation reaction in a reaction kettle, the flow of sodium ferrocyanide is controlled, the reaction pH is kept at 7.8, and the reacted slurry is aged for 12 hours. And leading the Prussian white slurry in the aging tank to a centrifugal machine for filtering, removing mother liquor in the slurry, and leaving a filter cake in the centrifugal machine.
(2) Coating Prussian white: and (3) keeping the centrifuge rotating at 20Hz, then introducing 1mol/L potassium nitrate solution into the centrifuge to wash the filter cake, wherein the consumption of potassium nitrate is 50% of that of Prussian Bai Maer in the centrifuge, calculating the flow of the potassium sulfate solution, and enabling the time for washing the Prussian white filter cake to be 10 minutes, wherein potassium ions partially replace sodium ions on the Prussian white surface, so as to form a coating layer. The coating utilization of potassium nitrate was tested to be about 20% with potassium replacing about 5% of the sodium.
(3) Washing and drying: and (3) continuously washing the filter cake which is coated by washing with the potassium nitrate solution in the centrifugal machine by using pure water to remove impurities in the filter cake, wherein the volume of washing water is 0.4 times that of the aged slurry. Drying the filter cake at 170 ℃ to obtain a coated Prussian white product with a chemical formula of K 0.1 Na 1.9 MnFe(CN) 6 。
Example 6
Coated PrussianShibai of the chemical formula K 0.16 Na 1.84 MnFe(CN) 6 Comprises an inner core layer and a coating layer, wherein the inner core has a chemical formula of Na 2 MnFe(CN) 6 The chemical formula of the coating layer is K 2 MnFe(CN) 6 。
The preparation method of the coated Prussian white comprises the following steps:
(1) Prussian white was synthesized: 0.5mol/L sodium ferrocyanide solution, 1.6mol/L manganese sulfate solution and 2mol/L sodium citrate solution are prepared. Adding a proper amount of pure water into a reaction kettle, reaching the position of a stirring paddle, starting stirring, then introducing nitrogen into the reaction kettle to prevent oxidization, then raising the temperature to 65 ℃, and simultaneously pumping a sodium ferrocyanide solution, a manganese sulfate solution and a sodium citrate solution into the reaction kettle by using a metering pump, wherein the flow rate of the sodium citrate solution is 1.2 times that of the manganese sulfate solution. The solution is subjected to precipitation reaction in a reaction kettle, the flow of sodium ferrocyanide is controlled, the reaction pH is kept at 8.5, and the reacted slurry is aged for 18 hours. And leading the Prussian white slurry in the aging tank to a centrifugal machine for filtering, removing mother liquor in the slurry, and leaving a filter cake in the centrifugal machine.
(2) Coating Prussian white: and (3) keeping the centrifuge rotating at 40Hz, and then introducing 0.5mol/L potassium sulfate salt solution into the centrifuge to wash the filter cake, wherein the consumption of potassium sulfate is 50% of that of Prussian Bai Maer in the centrifuge, and calculating the flow of the potassium sulfate solution to enable the time for washing the Prussian white filter cake to be 5 minutes, and the potassium ions partially replace sodium ions on the Prussian white surface to form a coating layer. The coating utilization of potassium sulfate was tested to be about 20% with potassium replacing about 8% of the sodium.
(3) Washing and drying: and (3) continuously washing the filter cake which is coated by washing the potassium salt solution in the centrifugal machine by pure water to remove impurities in the filter cake, wherein the volume of washing water is 0.4 times that of the aged slurry. Drying the filter cake at 180deg.C to obtain coated Prussian white product with chemical formula of K 0.16 Na 1.84 MnFe(CN) 6 。
Example 7
Coated Prussian white with a chemical formula of K 0.12 Na 1.88 MnFe(CN) 6 Comprises an inner core layer and a coating layer, wherein the inner core has a chemical formula of Na 2 MnFe(CN) 6 The chemical formula of the coating layer is K 2 MnFe(CN) 6 。
The preparation method of the coated Prussian white comprises the following steps:
(1) Prussian white was synthesized: 0.5mol/L sodium ferrocyanide solution, 1.6mol/L manganese sulfate solution and 2mol/L sodium citrate solution are prepared. Adding a proper amount of pure water into a reaction kettle, reaching the position of a stirring paddle, starting stirring, then introducing nitrogen into the reaction kettle to prevent oxidization, then raising the temperature to 65 ℃, and simultaneously pumping a sodium ferrocyanide solution, a manganese sulfate solution and a sodium citrate solution into the reaction kettle by using a metering pump, wherein the flow rate of the sodium citrate solution is 1.2 times that of the manganese sulfate solution. The solution is subjected to precipitation reaction in a reaction kettle, the flow of sodium ferrocyanide is controlled, the reaction pH is kept at 8.5, and the reacted slurry is aged for 18 hours. And leading the Prussian white slurry in the aging tank to a centrifugal machine for filtering, removing mother liquor in the slurry, and leaving a filter cake in the centrifugal machine.
(2) Coating Prussian white: and (3) keeping the centrifuge to rotate at 10Hz, then introducing 0.5mol/L potassium sulfate salt solution into the centrifuge to wash the filter cake, wherein the consumption of potassium sulfate is 50% of that of Prussian Bai Maer in the centrifuge, calculating the flow of the potassium sulfate solution, and enabling the time for washing the Prussian white filter cake to be 8 minutes, wherein potassium ions partially replace sodium ions on the Prussian white surface, so as to form a coating layer. The coating utilization of potassium sulfate was tested to be about 20% with potassium replacing about 6% of the sodium.
(3) Washing and drying: and (3) continuously washing the filter cake which is coated by washing the potassium salt solution in the centrifugal machine by pure water to remove impurities in the filter cake, wherein the volume of washing water is 0.4 times that of the aged slurry. Drying the filter cake at 180deg.C to obtain coated Prussian white product with chemical formula of K 0.12 Na 1.88 MnFe(CN) 6 。
Example 8
Coated Prussian white with a chemical formula of K 0.12 Na 1.88 MnFe(CN) 6 Comprises an inner core layer and a coating layer, wherein the inner core has the chemical formulaIs Na (Na) 2 MnFe(CN) 6 The chemical formula of the coating layer is K 2 MnFe(CN) 6 。
The preparation method of the coated Prussian white comprises the following steps:
(1) Prussian white was synthesized: 0.5mol/L sodium ferrocyanide solution, 1.6mol/L manganese sulfate solution and 2mol/L sodium citrate solution are prepared. Adding a proper amount of pure water into a reaction kettle, reaching the position of a stirring paddle, starting stirring, then introducing nitrogen into the reaction kettle to prevent oxidization, then raising the temperature to 65 ℃, and simultaneously pumping a sodium ferrocyanide solution, a manganese sulfate solution and a sodium citrate solution into the reaction kettle by using a metering pump, wherein the flow rate of the sodium citrate solution is 1.2 times that of the manganese sulfate solution. The solution is subjected to precipitation reaction in a reaction kettle, the flow of sodium ferrocyanide is controlled, the reaction pH is kept at 8.5, and the reacted slurry is aged for 18 hours. And leading the Prussian white slurry in the aging tank to a centrifugal machine for filtering, removing mother liquor in the slurry, and leaving a filter cake in the centrifugal machine.
(2) Coating Prussian white: and (3) keeping the centrifuge to rotate at 60Hz, then introducing 0.5mol/L potassium sulfate salt solution into the centrifuge to wash the filter cake, wherein the consumption of potassium sulfate is 50% of that of Prussian Bai Maer in the centrifuge, calculating the flow of the potassium sulfate solution, and enabling the time for washing the Prussian white filter cake to be 8 minutes, wherein potassium ions partially replace sodium ions on the Prussian white surface, so as to form a coating layer. The coating utilization of potassium sulfate was tested to be about 20% with potassium replacing about 6% of the sodium.
(3) Washing and drying: and (3) continuously washing the filter cake which is coated by washing the potassium salt solution in the centrifugal machine by pure water to remove impurities in the filter cake, wherein the volume of washing water is 0.4 times that of the aged slurry. Drying the filter cake at 180deg.C to obtain coated Prussian white product with chemical formula of K 0.12 Na 1.88 MnFe(CN) 6 。
Example 9
Coated Prussian white with a chemical formula of K 0.14 Na 1.86 MnFe(CN) 6 Comprises an inner core layer and a coating layer, wherein the inner core has a chemical formula of Na 2 MnFe(CN) 6 The chemical formula of the coating layer isK 2 MnFe(CN) 6 。
The preparation method of the coated Prussian white comprises the following steps:
(1) Prussian white was synthesized: 0.5mol/L sodium ferrocyanide solution, 1.6mol/L manganese sulfate solution and 2mol/L sodium citrate solution are prepared. Adding a proper amount of pure water into a reaction kettle, reaching the position of a stirring paddle, starting stirring, then introducing nitrogen into the reaction kettle to prevent oxidization, then raising the temperature to 65 ℃, and simultaneously pumping a sodium ferrocyanide solution, a manganese sulfate solution and a sodium citrate solution into the reaction kettle by using a metering pump, wherein the flow rate of the sodium citrate solution is 1.2 times that of the manganese sulfate solution. The solution is subjected to precipitation reaction in a reaction kettle, the flow of sodium ferrocyanide is controlled, the reaction pH is kept at 8.5, and the reacted slurry is aged for 18 hours. And leading the Prussian white slurry in the aging tank to a centrifugal machine for filtering, removing mother liquor in the slurry, and leaving a filter cake in the centrifugal machine.
(2) Coating Prussian white: and (3) keeping the centrifuge rotating at 20Hz, and then introducing 0.5mol/L potassium sulfate salt solution into the centrifuge to wash the filter cake, wherein the consumption of potassium sulfate is 50% of that of Prussian Bai Maer in the centrifuge, and calculating the flow of the potassium sulfate solution to enable the time for washing the Prussian white filter cake to be 3 minutes, and the potassium ions partially replace sodium ions on the Prussian white surface to form a coating layer. The coating utilization of potassium sulfate was tested to be about 20% with potassium replacing about 7% of the sodium.
(3) Washing and drying: and (3) continuously washing the filter cake which is coated by washing the potassium salt solution in the centrifugal machine by pure water to remove impurities in the filter cake, wherein the volume of washing water is 0.4 times that of the aged slurry. Drying the filter cake at 180deg.C to obtain coated Prussian white product with chemical formula of K 0.14 Na 1.86 MnFe(CN) 6 。
Example 10
Coated Prussian white with a chemical formula of K 0.24 Na 1.76 MnFe(CN) 6 Comprises an inner core layer and a coating layer, wherein the inner core has a chemical formula of Na 2 MnFe(CN) 6 The chemical formula of the coating layer is K 2 MnFe(CN) 6 。
The preparation method of the coated Prussian white comprises the following steps:
(1) Prussian white was synthesized: 0.5mol/L sodium ferrocyanide solution, 1.6mol/L manganese sulfate solution and 2mol/L sodium citrate solution are prepared. Adding a proper amount of pure water into a reaction kettle, reaching the position of a stirring paddle, starting stirring, then introducing nitrogen into the reaction kettle to prevent oxidization, then raising the temperature to 65 ℃, and simultaneously pumping a sodium ferrocyanide solution, a manganese sulfate solution and a sodium citrate solution into the reaction kettle by using a metering pump, wherein the flow rate of the sodium citrate solution is 1.2 times that of the manganese sulfate solution. The solution is subjected to precipitation reaction in a reaction kettle, the flow of sodium ferrocyanide is controlled, the reaction pH is kept at 8.5, and the reacted slurry is aged for 18 hours. And leading the Prussian white slurry in the aging tank to a centrifugal machine for filtering, removing mother liquor in the slurry, and leaving a filter cake in the centrifugal machine.
(2) Coating Prussian white: and (3) keeping the centrifuge rotating at 20Hz, and then introducing 0.5mol/L potassium sulfate salt solution into the centrifuge to wash the filter cake, wherein the consumption of potassium sulfate is 50% of that of Prussian Bai Maer in the centrifuge, and calculating the flow of the potassium sulfate solution to enable the time for washing the Prussian white filter cake to be 15 minutes, and the potassium ions partially replace sodium ions on the Prussian white surface to form a coating layer. The coating utilization of potassium sulfate was tested to be about 20% with potassium replacing about 12% of the sodium.
(3) Washing and drying: and (3) continuously washing the filter cake which is coated by washing the potassium salt solution in the centrifugal machine by pure water to remove impurities in the filter cake, wherein the volume of washing water is 0.4 times that of the aged slurry. Drying the filter cake at 180deg.C to obtain coated Prussian white product with chemical formula of K 0.24 Na 1.76 MnFe(CN) 6 。
Comparative example 1
Comparative document 1 is a non-coated Prussian white product prepared in the same manner as in example 1, except that the potassium salt solution was not used to wash the cake in step (2), and the chemical formula is Na 2 MnFe(CN) 6 。
Comparative example 2
The comparison document 2 is a method for preparing coated Prussian white by adopting a traditional coating method in a reaction kettle, and specifically comprises the following steps:
(1) Prussian white was synthesized: preparing 0.4mol/L sodium ferrocyanide solution, 2mol/L manganese sulfate solution and 2mol/L sodium citrate solution. Adding a proper amount of pure water into a reaction kettle, reaching the position of a stirring paddle, starting stirring, then introducing nitrogen into the reaction kettle to prevent oxidization, then raising the temperature to 75 ℃, and simultaneously pumping a sodium ferrocyanide solution, a manganese sulfate solution and a sodium citrate solution into the reaction kettle by using a metering pump, wherein the flow rate of the sodium citrate solution is 2 times that of the manganese sulfate solution. The solution is subjected to precipitation reaction in a reaction kettle, the flow of sodium ferrocyanide is controlled, the reaction pH is kept at 8.2, and the reacted slurry is aged for 12 hours. And leading the Prussian white slurry in the aging tank to a centrifugal machine for filtering, and removing mother liquor in the slurry to obtain a Prussian white filter cake.
(2) Coating Prussian white: adding Prussian white filter cake into a reaction kettle, adding water for pulping, starting stirring, and adding 0.5mol/L potassium sulfate solution into the kettle, wherein the consumption of potassium sulfate is 10% of that of Prussian Bai Maer in the reaction kettle. Coating is carried out in a reaction kettle, and the potassium sulfate almost completely reacts. Aging for 30min, filtering and washing the slurry in the reaction kettle in a centrifuge to obtain a filter cake, and drying the filter cake at 180deg.C to obtain coated Prussian white product with chemical formula of K 0.2 Na 1.8 MnFe(CN) 6 。
Product effect test
The Prussian white products prepared in examples 1-10 and comparative examples 1-2 were tested.
The specific test method and test results are as follows:
(1) The coated Prussian white prepared in example 1, comparative example 2, and the uncoated Prussian white product prepared in comparative example 1 were analyzed using a scanning electron microscope.
Fig. 2 is an SEM image of coated Prussian white prepared in example 1, and a small amount of coating was seen on the surface of the material when the coating process was performed in a centrifuge. FIG. 3 is an SEM image of uncoated Prussian white prepared in comparative example 1, the material was uncoated, the surface was smooth, and there was no attachment; fig. 4 is an SEM image of the coated Prussian white prepared in comparative example 2, in which the coating process was performed in a reaction kettle for 30min, a large number of holes appeared on the surface of the material, and the morphology was severely deteriorated, which was caused by etching the inside of the material with potassium ions, and also, there was a small amount of attachments formed by recrystallization after dissolution on the surface of the material.
(2) The Prussian white products prepared in examples 1 to 10 and comparative examples 1 to 2 were tested for particle size using a dry particle sizer.
(3) The Prussian white products prepared in examples 1 to 10 and comparative examples 1 to 2 were tested for moisture content (wt%) by drying at 150℃for 1 hour using an automatic moisture meter.
(4) The Prussian white products prepared in examples 1-10 and comparative examples 1-2 were used as positive electrode sheets, and sodium metal was used as negative electrode, naPF 6 The Ethylene Carbonate (EC)/diethyl carbonate (DEC) solution is used as electrolyte, and the button half-cell is assembled in a glove box. Then, the charge-discharge specific capacities of the batteries were tested at 0.1C and 5C rates, respectively, in a voltage range of 2.0-4.0V.
The test results are shown in Table 1.
Table 1 test results
As is clear from table 1, in example 1, the morphology of the material was less changed than that of comparative example 1, but the moisture content of the material after coating (coated Prussian white prepared in example 1) was significantly reduced, the specific discharge capacity at 0.1C was almost unchanged, but the specific discharge capacity at 5C was significantly improved. Compared with comparative example 1, the coated Prussian white surface obtained by the conventional method has a large number of holes, the moisture is not reduced and increased, the discharge specific capacities of 0.1C and 5C are greatly reduced, and the product performance is seriously deteriorated. The coated Prussian white prepared in examples 2-6 has similar effects to example 1, and has reduced moisture content and significantly improved specific 5C discharge capacity compared with comparative example 1. Compared with comparative example 1, the 5C discharge specific capacity of the coated Prussian white prepared in examples 7-10 is also significantly improved; the specific discharge capacity of 0.1C was comparable to that of examples 1-6, but the specific discharge capacity of water content was slightly inferior to that of 5C. Therefore, the coated Prussian white prepared by a washing mode under the action of centrifugal force can reduce the water absorption and the moisture content of the Prussian white, and the charge-discharge specific capacity of a sodium ion battery prepared by the coated Prussian white under the high-rate condition is remarkably improved; the rotational frequency and washing time for centrifugal force also affect the stability of sodium batteries, especially the specific discharge capacity at high rates (5C).
Claims (7)
1. A coated Prussian white is characterized in that the chemical formula of the coated Prussian white is K x Na 2-x AFe(CN) 6 The coating Prussian white has a chemical formula of Na 2 AFe(CN) 6 The inner core and the chemical formula of (C) are K 2 AFe(CN) 6 Wherein A is Ni 2+ 、Co 2+ 、Mn 2+ 、Fe 2+ At least one of (a) and (b);
in the chemical formula, x=0.06-0.3;
the preparation method of the coated Prussian white comprises the following steps:
under the action of centrifugal force, washing Prussian white by adopting a potassium salt solution to replace at least part of sodium ions on the surface of the Prussian white by potassium ions; then washing and drying to obtain coated Prussian white; the rotation frequency for generating the centrifugal force is 10-60Hz;
the washing time is 2-15 minutes.
2. The coated Prussian white according to claim 1, wherein the rotational frequency at which the centrifugal force is generated is 15-50Hz.
3. The coated Prussian white according to claim 1, wherein the potassium salt in the potassium salt solution is at least one of potassium sulfate, potassium nitrate, potassium chloride, and potassium citrate.
4. The coated Prussian white according to claim 1, wherein the concentration of the potassium salt solution is 0.3-3mol/L.
5. The coated Prussian white according to claim 1, wherein the time for washing the Prussian white with the potassium salt solution is 5-10 minutes.
6. A positive electrode sheet comprising the coated Prussian white according to claim 1.
7. A sodium ion battery comprising the positive electrode sheet of claim 6.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210914516.1A CN115196653B (en) | 2022-07-29 | 2022-07-29 | Coated Prussian white and preparation method and application thereof |
| PCT/CN2022/119466 WO2024021255A1 (en) | 2022-07-29 | 2022-09-16 | Coated prussian white, method for preparing same, and use thereof |
| FR2308156A FR3138425A1 (en) | 2022-07-29 | 2023-07-28 | COATED PRUSSIAN WHITE (PW) AND PREPARATION METHOD AND USE THEREOF |
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| CN202210914516.1A CN115196653B (en) | 2022-07-29 | 2022-07-29 | Coated Prussian white and preparation method and application thereof |
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Citations (4)
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| JP2020092086A (en) * | 2018-11-26 | 2020-06-11 | 学校法人東京理科大学 | Positive electrode material for potassium ion secondary battery and method of producing the same |
| CN112645354A (en) * | 2020-12-21 | 2021-04-13 | 电子科技大学 | Surface-modified sodium-manganese-iron-based Prussian blue material and preparation method and application thereof |
| CN114188502A (en) * | 2021-11-30 | 2022-03-15 | 湖南钠方新能源科技有限责任公司 | Prussian white composite material and preparation method and application thereof |
| CN114497472A (en) * | 2021-12-08 | 2022-05-13 | 电子科技大学长三角研究院(湖州) | Prussian blue positive electrode material with multilayer structure and preparation method and application thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| DE2366064C3 (en) * | 1973-12-10 | 1981-10-22 | Degussa Ag, 6000 Frankfurt | Production of Prussian blue by converting sodium ferrocyanide |
| US9130234B2 (en) * | 2011-06-22 | 2015-09-08 | Alveo Energy, Inc. | Stabilization of battery electrodes |
| JP2015079685A (en) * | 2013-10-18 | 2015-04-23 | 株式会社豊田中央研究所 | Aqueous solution-based secondary battery |
| CN106549155A (en) * | 2016-10-20 | 2017-03-29 | 河南师范大学 | A kind of potassium sodium ferromanganese base prussian blue electrode material and its preparation method and application |
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2022
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| JP2020092086A (en) * | 2018-11-26 | 2020-06-11 | 学校法人東京理科大学 | Positive electrode material for potassium ion secondary battery and method of producing the same |
| CN112645354A (en) * | 2020-12-21 | 2021-04-13 | 电子科技大学 | Surface-modified sodium-manganese-iron-based Prussian blue material and preparation method and application thereof |
| CN114188502A (en) * | 2021-11-30 | 2022-03-15 | 湖南钠方新能源科技有限责任公司 | Prussian white composite material and preparation method and application thereof |
| CN114497472A (en) * | 2021-12-08 | 2022-05-13 | 电子科技大学长三角研究院(湖州) | Prussian blue positive electrode material with multilayer structure and preparation method and application thereof |
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| CN115196653A (en) | 2022-10-18 |
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