CN116454283A - Potassium ion battery positive electrode additive and preparation method and application thereof - Google Patents
Potassium ion battery positive electrode additive and preparation method and application thereof Download PDFInfo
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- CN116454283A CN116454283A CN202310517745.4A CN202310517745A CN116454283A CN 116454283 A CN116454283 A CN 116454283A CN 202310517745 A CN202310517745 A CN 202310517745A CN 116454283 A CN116454283 A CN 116454283A
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- 229910001414 potassium ion Inorganic materials 0.000 title claims abstract description 114
- NPYPAHLBTDXSSS-UHFFFAOYSA-N Potassium ion Chemical compound [K+] NPYPAHLBTDXSSS-UHFFFAOYSA-N 0.000 title claims abstract description 101
- 239000000654 additive Substances 0.000 title claims abstract description 59
- 230000000996 additive effect Effects 0.000 title claims abstract description 59
- 238000002360 preparation method Methods 0.000 title abstract description 16
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims abstract description 42
- 239000011591 potassium Substances 0.000 claims abstract description 42
- 229910052700 potassium Inorganic materials 0.000 claims abstract description 42
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 37
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 25
- 239000011248 coating agent Substances 0.000 claims abstract description 20
- 238000000576 coating method Methods 0.000 claims abstract description 20
- 239000002245 particle Substances 0.000 claims description 28
- 239000000843 powder Substances 0.000 claims description 26
- 229910052782 aluminium Inorganic materials 0.000 claims description 17
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 17
- 238000000227 grinding Methods 0.000 claims description 16
- 238000000034 method Methods 0.000 claims description 15
- 239000002904 solvent Substances 0.000 claims description 14
- 238000001035 drying Methods 0.000 claims description 13
- 239000000243 solution Substances 0.000 claims description 13
- 239000003575 carbonaceous material Substances 0.000 claims description 11
- 238000002156 mixing Methods 0.000 claims description 11
- 238000005245 sintering Methods 0.000 claims description 11
- 239000000203 mixture Substances 0.000 claims description 9
- 239000002253 acid Substances 0.000 claims description 8
- -1 graphite alkyne Chemical class 0.000 claims description 7
- 229910021389 graphene Inorganic materials 0.000 claims description 6
- 239000011259 mixed solution Substances 0.000 claims description 6
- WQZGKKKJIJFFOK-GASJEMHNSA-N Glucose Natural products OC[C@H]1OC(O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-GASJEMHNSA-N 0.000 claims description 5
- 239000008103 glucose Substances 0.000 claims description 5
- 229910002804 graphite Inorganic materials 0.000 claims description 5
- 239000010439 graphite Substances 0.000 claims description 5
- 229910021393 carbon nanotube Inorganic materials 0.000 claims description 4
- 239000002041 carbon nanotube Substances 0.000 claims description 4
- WQZGKKKJIJFFOK-VFUOTHLCSA-N beta-D-glucose Chemical compound OC[C@H]1O[C@@H](O)[C@H](O)[C@@H](O)[C@@H]1O WQZGKKKJIJFFOK-VFUOTHLCSA-N 0.000 claims description 3
- 229910021385 hard carbon Inorganic materials 0.000 claims description 3
- 229910021384 soft carbon Inorganic materials 0.000 claims description 3
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 2
- 229940037179 potassium ion Drugs 0.000 description 84
- 239000011267 electrode slurry Substances 0.000 description 18
- 208000028659 discharge Diseases 0.000 description 11
- 239000003792 electrolyte Substances 0.000 description 11
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 8
- 239000000463 material Substances 0.000 description 8
- 230000008569 process Effects 0.000 description 8
- 238000005096 rolling process Methods 0.000 description 8
- 230000015572 biosynthetic process Effects 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 7
- 239000007774 positive electrode material Substances 0.000 description 7
- 239000006258 conductive agent Substances 0.000 description 6
- 238000005520 cutting process Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 239000011883 electrode binding agent Substances 0.000 description 5
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 4
- 239000006256 anode slurry Substances 0.000 description 4
- 239000003795 chemical substances by application Substances 0.000 description 4
- 239000011888 foil Substances 0.000 description 4
- 238000002347 injection Methods 0.000 description 4
- 239000007924 injection Substances 0.000 description 4
- 229910052744 lithium Inorganic materials 0.000 description 4
- 239000012528 membrane Substances 0.000 description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 229910001415 sodium ion Inorganic materials 0.000 description 4
- 230000001502 supplementing effect Effects 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 3
- FKNQFGJONOIPTF-UHFFFAOYSA-N Sodium cation Chemical compound [Na+] FKNQFGJONOIPTF-UHFFFAOYSA-N 0.000 description 3
- 239000011889 copper foil Substances 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 238000003801 milling Methods 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- 239000002033 PVDF binder Substances 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 2
- 239000004743 Polypropylene Substances 0.000 description 2
- DPXJVFZANSGRMM-UHFFFAOYSA-N acetic acid;2,3,4,5,6-pentahydroxyhexanal;sodium Chemical compound [Na].CC(O)=O.OCC(O)C(O)C(O)C(O)C=O DPXJVFZANSGRMM-UHFFFAOYSA-N 0.000 description 2
- 239000004411 aluminium Substances 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 239000001768 carboxy methyl cellulose Substances 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000000875 high-speed ball milling Methods 0.000 description 2
- 238000005184 irreversible process Methods 0.000 description 2
- 239000007773 negative electrode material Substances 0.000 description 2
- 231100000252 nontoxic Toxicity 0.000 description 2
- 230000003000 nontoxic effect Effects 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- 229920001155 polypropylene Polymers 0.000 description 2
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 2
- 230000002035 prolonged effect Effects 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 description 2
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 description 2
- 239000007784 solid electrolyte Substances 0.000 description 2
- 229920003048 styrene butadiene rubber Polymers 0.000 description 2
- 239000002562 thickening agent Substances 0.000 description 2
- 239000012498 ultrapure water Substances 0.000 description 2
- 229920000049 Carbon (fiber) Polymers 0.000 description 1
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 1
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 1
- 239000003929 acidic solution Substances 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 239000006183 anode active material Substances 0.000 description 1
- 239000010405 anode material Substances 0.000 description 1
- 239000003125 aqueous solvent Substances 0.000 description 1
- 229910021383 artificial graphite Inorganic materials 0.000 description 1
- 239000006229 carbon black Substances 0.000 description 1
- 239000004917 carbon fiber Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 230000001351 cycling effect Effects 0.000 description 1
- 238000009831 deintercalation Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000009830 intercalation Methods 0.000 description 1
- 230000002687 intercalation Effects 0.000 description 1
- DCYOBGZUOMKFPA-UHFFFAOYSA-N iron(2+);iron(3+);octadecacyanide Chemical class [Fe+2].[Fe+2].[Fe+2].[Fe+3].[Fe+3].[Fe+3].[Fe+3].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-] DCYOBGZUOMKFPA-UHFFFAOYSA-N 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000010030 laminating Methods 0.000 description 1
- 229910001416 lithium ion Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000012982 microporous membrane Substances 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 239000012454 non-polar solvent Substances 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 239000002798 polar solvent Substances 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 229920005569 poly(vinylidene fluoride-co-hexafluoropropylene) Polymers 0.000 description 1
- 229920000447 polyanionic polymer Polymers 0.000 description 1
- 229920000131 polyvinylidene Polymers 0.000 description 1
- 229940070017 potassium supplement Drugs 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Classifications
-
- 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
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F7/00—Compounds of aluminium
- C01F7/48—Halides, with or without other cations besides aluminium
- C01F7/50—Fluorides
- C01F7/54—Double compounds containing both aluminium and alkali metals or alkaline-earth metals
-
- 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
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
-
- 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
- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
-
- 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)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Organic Chemistry (AREA)
- Materials Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
The invention provides a positive electrode additive of a potassium ion battery, a preparation method and application thereof, wherein the positive electrode additive of the potassium ion battery at least comprises potassium hexafluoroaluminate, and the potassium hexafluoroaluminate has a carbon coating structure. The positive electrode additive of the potassium ion battery, the preparation method and the application thereof can make up the coulomb efficiency of the first cycle of the potassium ion battery and increase the cycle stability of the potassium ion battery.
Description
Technical Field
The invention relates to the technical field of power batteries, in particular to a positive electrode additive of a potassium ion battery, and a preparation method and application thereof.
Background
The potassium resources are abundant in reserves in the crust, are widely distributed, and compared with a sodium ion battery, the standard electrode potential of potassium is close to the standard electrode potential of lithium, so that the working voltage of the potassium ion battery is higher than that of the sodium ion battery, the radius of solvated potassium ions is smaller than that of the sodium ions, and the potassium ions have higher migration speed. Therefore, compared with lithium ion batteries and sodium ion batteries, the potassium ion batteries have relatively low production cost and are suitable for being used as large-scale energy storage equipment in the two-wheel vehicle market.
However, in the first charge and discharge stage of the potassium ion battery, a solid electrolyte interface (Solid Electrolyte Interface, SEI) is formed at the interface of the anode material, and the formation of an SEI film is an irreversible process, so that the active potassium is permanently lost, and the coulombic efficiency (Initial Coulombic Efficiency, ICE) of the first cycle of the potassium ion battery is reduced.
Disclosure of Invention
The invention provides a positive electrode additive of a potassium ion battery, a preparation method and application thereof, which can provide the positive electrode additive of the potassium ion battery, improve the energy density of the potassium ion battery, compensate the coulomb efficiency of the first cycle, increase the cycle stability of the potassium ion battery and improve the performance of a lithium battery.
In order to solve the technical problems, the invention is realized by the following technical scheme.
The invention provides a positive electrode additive of a potassium ion battery, which at least comprises potassium hexafluoroaluminate, wherein the potassium hexafluoroaluminate has a carbon coating structure.
In one embodiment of the invention, the carbon coating amount of the positive electrode additive of the potassium ion battery is 1% -5%.
In one embodiment of the invention, the particle size of the positive electrode additive of the potassium ion battery is less than 30 μm.
The invention also provides a method for preparing the positive electrode additive of the potassium ion battery, which comprises the following steps:
mixing a potassium source, an aluminum source and an acid solution in a solvent to obtain a mixed solution;
drying the mixed solution to form gel;
mixing the gel with a carbon material, and grinding to obtain powder particles; and
and sintering the powder particles under preset conditions, and grinding to obtain the carbon-coated potassium hexafluoroaluminate.
In one embodiment of the present invention, the size of the powder particles is less than 5 μm.
In one embodiment of the invention, the potassium source is selected from K 2 O、K 2 CO 3 、KOH、K 2 C 2 O 4 、KNO 3 、KCH 3 COO、K 2 SO 4 、K 2 SO 3 、KNO 2 、KS 2 O 3 、K 2 S 2 O 8 、KCl、K 3 PO 4 、KH 2 PO 4 、KClO 3 、KClO 4 、KSiO 3 NKF, KCN or K 3 [Fe(CN) 6 ]·H 2 And any one or more of O are mixed.
In one embodiment of the present invention, the aluminum source is selected from the group consisting of Al 2 O 3 、Al 2 (SO 4 ) 3 、AlCl 3 Or Al (NO) 3 ) 3 Any one or a mixture of a plurality of them.
In an embodiment of the present invention, the carbon material is selected from any one or a mixture of several of glucose, carbon nanotubes, graphene, graphite alkyne, soft carbon or hard carbon.
In one embodiment of the invention, the sintering temperature of the powder particles is 800-900 ℃ and the sintering time is 3-4 h.
The invention also provides an electrochemical device which comprises a positive electrode, a negative electrode and a diaphragm, wherein the positive electrode comprises the positive electrode additive of the potassium ion battery.
In summary, the invention provides a positive electrode additive for a potassium ion battery, a preparation method and application thereof, and the prepared positive electrode additive for the potassium ion battery is insensitive to humidity and can exist in air stably. The prepared positive electrode additive of the potassium ion battery can be used as a positive electrode potassium supplementing agent, gas is not released in the charging and discharging process, potassium ions consumed by forming an SEI film on the surface of a negative electrode are used for compensating the loss of first coulombic efficiency of the positive electrode and the negative electrode, and therefore the cycle stability of the potassium ion battery is improved, and the performance of a lithium battery is improved. Meanwhile, the material for preparing the positive electrode additive of the potassium ion battery is nontoxic, the preparation process is simple, and the cost is low.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a flow chart of the preparation of a positive electrode additive for a potassium ion battery according to an embodiment.
Detailed Description
Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention.
It should be understood that the present invention may be embodied in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Unless otherwise specified, "%" and "parts" shown in the following examples refer to "% by mass" and "parts by mass", respectively.
The technical solution of the present invention will be described in further detail below with reference to several embodiments and the accompanying drawings, and it is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In a potassium ion power battery, the battery negative electrode is polarized when charged for the first time, and an SEI film is formed on the surface of the negative electrode through precipitation. The formation of an SEI film is an irreversible process, which causes permanent loss of active potassium, resulting in a decrease in coulombic efficiency of the first cycle of the potassium ion battery. The positive electrode additive of the potassium ion battery, the preparation method and the application thereof provided by the invention have the advantages that the chemical property of the prepared positive electrode additive of the potassium ion battery is stable, the preparation process is simple, the material is nontoxic, the positive electrode additive is used as a positive electrode potassium supplementing agent of the potassium ion battery, potassium ions are released, the loss of the potassium ions forming an SEI film on the surface of a negative electrode is compensated, the effect of supplementing potassium is achieved, and the positive electrode additive can be used for preparing different types of potassium ion batteries and has excellent effect.
In one embodiment, the positive electrode additive of the potassium ion battery has the advantages of being insensitive to humidity, being stable in air, and not releasing gas during charge and discharge. In this embodiment, the positive electrode additive of the potassium ion battery is, for example, potassium hexafluoroaluminate (K) 3 AlF 6 ) The potassium hexafluoroaluminate is added into positive electrode slurry of a potassium ion battery, is assembled into the potassium ion battery, can play a role of serving as a positive electrode material, and takes off potassium ions preferentially to the positive electrode material when the potassium ion battery is charged and discharged for the first time, so that an SEI film is formed on the surface of a negative electrode, the loss of the potassium ions of the positive electrode material is reduced, and the reduction of the initial coulombic efficiency of the potassium ion battery is avoided.
In one embodiment, the positive electrode additive of the potassium ion battery is coated, for example, by a carbon material, in this embodiment, the carbon coating amount of the potassium hexafluoroaluminate is, for example, 1% -5%, and the particle size of the carbon coated potassium hexafluoroaluminate is, for example, less than 30 μm. The carbon coating treatment is carried out on the positive electrode additive of the potassium ion battery, and the carbon coating amount is set, so that the conductivity and corrosion resistance of the positive electrode additive of the potassium ion battery are improved, the polarization of an electrode is reduced, the thermal effect of the battery is reduced, and the service life of the potassium ion battery is prolonged. In this embodiment, the carbon-coated potassium hexafluoroaluminate is obtained by, for example, mixing and reacting a potassium source, an aluminum source, an acid solution, and a carbon material in a solvent, and grinding and pulverizing the mixture after the processes of filtering, washing, heating, drying, cooling, and the like.
As shown in FIG. 1, the invention also provides a specific preparation method of the positive electrode additive of the potassium ion battery, and the positive electrode additive of the potassium ion battery is obtained through steps S10-S40.
And step S10, mixing the potassium source, the aluminum source and the acid solution in a solvent to obtain a mixed solution.
And step S20, drying the mixed solution to form gel.
And step S30, mixing the gel with a carbon material, and grinding to obtain powder particles.
And S40, sintering and grinding the powder particles to obtain the carbon-coated potassium hexafluoroaluminate.
In one embodiment, as shown in fig. 1, in step S10, a potassium source, an aluminum source, and an acid solution are added to a solvent at a predetermined molar ratio and mixed. Wherein the potassium source is selected from K 2 O、K 2 CO 3 、KOH、K 2 C 2 O 4 、KNO 3 、KCH 3 COO、K 2 SO 4 、K 2 SO 3 、KNO 2 、KS 2 O 3 、K 2 S 2 O 8 、KCl、K 3 PO 4 、KH 2 PO 4 、KClO 3 、KClO 4 、KSiO 3 NKF, KCN or K 3 [Fe(CN) 6 ]·H 2 O, and an aluminum source selected from, for example, al 2 O 3 、Al 2 (SO 4 ) 3 、AlCl 3 Or Al (NO) 3 ) 3 Any one or a mixture of a plurality of acid solutionsFor example, an acidic solution having strong corrosiveness such as hydrofluoric acid is selected. In this embodiment, the potassium source is, for example, K 2 CO 3 The aluminium source being, for example, selected from Al 2 (SO 4 ) 3 The carbon material is, for example, glucose, and the acid solution is, for example, hydrofluoric acid. In other embodiments, the materials are, for example, different combinations of other choices.
As shown in fig. 1, in an embodiment, in step S10, the solvent is selected to be an aqueous solvent such as pure water, and the capacity of the solvent is set according to the content of the raw material, for example. The raw materials and the solvent are sequentially added into a reaction kettle to be stirred, wherein the stirring speed is 40 rpm/min-60 rpm/min, and the stirring time is 4 h-6 h, so that uniform solution is obtained. In this embodiment, the potassium source is, for example, K 2 CO 3 The aluminium source being, for example, selected from Al 2 (SO 4 ) 3 Acid solution, e.g. hydrofluoric acid, and K 2 CO 3 、Al 2 (SO 4 ) 3 And hydrofluoric acid, for example, at a molar ratio of 3:1:12.
in one embodiment, as shown in fig. 1, in step S20, the uniform solution obtained in step S10 is subjected to a drying treatment at, for example, 140 to 160 ℃ for, for example, 2 to 4 hours, to form a gel.
As shown in fig. 1, in an embodiment, in step S30, the gel and the carbon material obtained in step S20 are added to a grinding tank, and a grinding process is performed while adding a medium. The carbon material is selected from any one or a mixture of glucose, carbon nanotubes, graphene, graphite alkyne, soft carbon or hard carbon, the added medium is pure water, the grinding process is selected from one of high-speed ball milling, air flow milling, raymond mill, rod mill or vibration mill, and the grinding process is selected from high-speed ball ink in the embodiment. Grinding to obtain carbon-coated powder particles, drying the powder particles at 45-60 deg.c for 9-11 hr to obtain the powder particles with particle size smaller than 5 microns.
In one embodiment, as shown in fig. 1, in step S40, the powder particles in step S30 are subjected to sintering and grinding processes. The sintering temperature of the powder particles is 800-900 ℃ for example, and the sintering time is 3-4 hours for example. The milling process is, for example, one of a high speed ball mill, an air flow mill, a Raymond mill, a rod mill or a vibratory mill, and in this embodiment, the milling process is, for example, an air flow ink. And grinding the sintered powder particles for a preset time to obtain the potassium ion battery positive electrode additive, namely carbon-coated potassium hexafluoroaluminate powder, wherein the particle size of the ground potassium ion battery positive electrode additive is smaller than 30 mu m. The particle size of the powder particles is limited through a powder process, so that the specific surface area of the positive electrode additive of the potassium ion battery is increased, and the lithium intercalation/deintercalation rate of the positive electrode additive of the potassium ion battery in the first charge and discharge is improved.
The present invention also provides an electrochemical device, in this embodiment, the electrochemical device is, for example, a potassium ion battery, and is, for example, one of a liquid potassium ion battery and a solid potassium ion battery, and the potassium ion battery includes, for example, a positive electrode, a negative electrode, a separator and an electrolyte. The positive electrode comprises the positive electrode additive of the potassium ion battery, namely, the slurry containing the positive electrode additive of the potassium ion battery is coated on a positive electrode current collector of the potassium ion battery to prepare the potassium ion battery. The positive electrode additive of the potassium ion battery provided by the invention is used as a positive electrode potassium supplementing agent, potassium ions are provided in preference to the positive electrode of the battery in the first charge and discharge stage of the potassium ion battery when an SEI film is formed, so that the loss of positive electrode potassium ions is avoided, the loss of first coulombic efficiency of the positive electrode and the negative electrode is compensated, and the cycle stability of the potassium ion battery is improved. In one embodiment, the potassium-ion cell is obtained, for example, by steps S11-S14.
And S11, mixing the potassium ion positive electrode additive obtained in the steps S10-S40 with other positive electrode slurry materials to obtain positive electrode slurry, coating the positive electrode slurry on a positive electrode current collector, and obtaining a positive electrode sheet through drying, rolling and die cutting processes.
And step S12, mixing the anode slurry materials to obtain anode slurry, coating the anode slurry on an anode current collector, and obtaining an anode pole piece through drying, rolling and die cutting processes.
And S13, laminating the diaphragm and the pole piece according to a set sequence to obtain the potassium ion battery laminated core.
And S14, assembling the potassium ion battery core, the cover plate and the shell, and obtaining the potassium ion battery through the processes of liquid injection, standing, formation and the like.
In an embodiment, in step S11, the materials of the positive electrode slurry include, for example, a positive electrode active material, a positive electrode additive, a positive electrode binder, a positive electrode conductive agent, and a positive electrode solvent. For example, the positive electrode active material, the positive electrode additive, the positive electrode binder and the positive electrode conductive agent are mixed according to a certain proportion, and added into the positive electrode solvent to be mixed uniformly, so as to obtain the positive electrode slurry. The positive electrode active material is, for example, one or more of layered oxides, polyanion compounds or Prussian blue compounds are mixed, the positive electrode additive is, for example, carbon-coated potassium hexafluoroaluminate prepared by the steps S10-S40, the positive electrode binder is, for example, one or more of polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene or polyvinylidene fluoride-trifluoroethylene binders are mixed, the positive electrode conductive agent is, for example, conductive carbon black (Super P), conductive graphite, carbon fibers, carbon nano tubes, graphene and mixed conductive slurry thereof are selected, the positive electrode solvent is, for example, a polar solvent such as N-Methyl-2-pyrrrolone (NMP), and the environmental humidity of the slurry preparation is, for example, less than 10%.
In an embodiment, in step S11, the positive electrode slurry is coated on a positive electrode current collector, for example, an aluminum foil is selected, the thickness of the aluminum foil is for example, 10 μm to 12 μm, and the aluminum foil is provided with a conductive coating, for example, a composite material of graphene and carbon black. The coating density of the positive electrode slurry is, for example, 360g/m 2 ～400g/m 2 . After coating, the positive electrode sheet is subjected to a baking and rolling treatment, and the compacted density is, for example, 2.6g/cc to 2.7g/cc. And finally, performing die cutting treatment to obtain the positive electrode plate.
In an embodiment, in step S12, the materials of the anode slurry include, for example, an anode active material, an anode additive, an anode thickener, an anode conductive agent, and an anode solvent. For example, the negative electrode active material, the negative electrode additive, the negative electrode binder and the negative electrode conductive agent are mixed according to a certain proportion, and added into the negative electrode solvent to be uniformly mixed, so as to obtain the negative electrode slurry. The negative electrode active material is, for example, one or a mixture of carbon-based materials, alloy materials, or organic compound materials, the negative electrode thickener is, for example, sodium carboxymethyl cellulose, the negative electrode binder is, for example, an aqueous binder such as Styrene-butadiene rubber (SBR), and the negative electrode conductive agent is, for example, one or a mixture of conductive carbon black (Super P), conductive graphite, graphene, or the like. The negative electrode solvent is, for example, a nonpolar solvent such as high purity water.
In one embodiment, in step S12, a negative electrode slurry is coated on a negative electrode current collector, for example, a copper foil is selected, and the thickness of the copper foil is, for example, 5 μm to 7 μm, and the coating density of the negative electrode slurry is, for example, 140g/m 2 ～160g/m 2 . After coating, the negative electrode sheet is subjected to a drying and rolling treatment, and the compacted density is, for example, 1.6g/cc to 1.7g/cc. And finally, performing die cutting treatment to obtain the negative electrode plate.
In one embodiment, in step S13, the separator is, for example, one of a polyethylene separator, a polypropylene separator, and a composite multi-layer microporous membrane of a polyethylene separator and a polypropylene separator, and the porosity of the separator is, for example, 38-43%, so as to ensure the isolation effect of the separator on the positive electrode sheet and the negative electrode sheet and the permeation effect of potassium ions. And the membrane, the positive pole piece and the negative pole piece are sequentially overlapped and laminated according to the sequence of the membrane, the positive pole piece, the membrane, the negative pole piece and the membrane, so as to obtain the potassium ion battery cell.
In an embodiment, in step S14, the cover plate includes, for example, a positive cover plate and a negative cover plate, the outer shell is, for example, an aluminum shell, and the thickness of the aluminum shell is, for example, 0.25mm to 0.35mm. And assembling the potassium ion battery cell, the positive electrode cover plate, the negative electrode cover plate and the aluminum shell, and then carrying out liquid injection and formation treatment. In this embodiment, the electrolyte is injected twice, the volume of the electrolyte injected once is 80% of the volume of the electrolyte required, the electrolyte is subjected to high-temperature standing treatment after the electrolyte is injected once, and then the formation treatment is performed, and a stepped formation charging system is adopted, for example. Finally, secondary injection is carried out, and the volume of the electrolyte injected for the second time is 20% of the volume of the electrolyte required, so that the potassium ion battery is obtained.
Example 1
The preparation method of the potassium ion positive electrode additive comprises the following specific steps.
Step S10, K is taken 2 CO 3 Powder, al 2 (SO 4 ) 3 And HF in a molar ratio of 3:1:12 are sequentially added to a reaction vessel containing 200L of pure water, and stirred at 50rpm/min for 5 hours at 25℃to obtain a uniform solution.
Step S20, drying the solution obtained in step S10 at 150 ℃ for 2 hours to form gel.
And step S30, placing the gel obtained in the step S20 into a grinding tank, adding glucose, performing high-speed ball milling by taking pure water as a medium to obtain powder particles with the particle size smaller than 5 mu m, and drying the powder particles at 50 ℃ for 10 hours.
Step S40, sintering the powder particles obtained in the step S30 for 3 hours at 800 ℃, cooling to room temperature, and performing air flow grinding until the particle size is smaller than 30 mu m to obtain the carbon-coated potassium ion battery positive electrode additive, namely the carbon-coated K 3 AlF 6 And (3) powder.
The carbon-coated potassium hexafluoroaluminate obtained in the steps S10 to S40 is used as a positive electrode additive to prepare a potassium ion battery, and the preparation method of the potassium ion battery comprises the following specific steps.
Step S11, K is carried out 2 Ti 4 O 9 Carbon-coated K obtained in steps S10 to S40 3 AlF 6 The mass ratio of the powder, the conductive carbon black and the polyvinylidene fluoride is 93.5:3:1:2.5 mixing, adding N-methyl pyrrolidone, stirring uniformly to obtain positive electrode slurry, coating the positive electrode slurry on carbon-coated aluminum foil, and drying, rolling and die cutting to obtain positive electrode plate, wherein the coating surface density of the positive electrode slurry is 380g/m 2 The density after rolling was 2.68g/cc.
Step S12, artificial graphite, conductive carbon black, sodium carboxymethyl cellulose and styrene-butadiene rubber are mixed according to the mass ratio of 96:0.5:1:2.5 mixing, adding into high-purity water, stirringUniformly preparing negative electrode slurry, coating the negative electrode slurry on copper foil, and then drying, rolling and die cutting to obtain a negative electrode plate, wherein the coating surface density of the negative electrode slurry is 150g/m 2 The density after rolling was 1.63g/cc.
And S13, stacking the positive electrode plate obtained in the step S11, the negative electrode plate obtained in the step S12 and the diaphragm sequentially according to the sequence of the diaphragm, the positive electrode plate, the diaphragm, the negative electrode plate and the diaphragm, and obtaining the potassium ion battery stacked core.
And S14, assembling the potassium ion battery stack core obtained in the step S13 with the anode cover plate, the cathode cover plate and the shell, injecting the electrolyte once, injecting the electrolyte with the required volume Of 80% once, standing for 36h, charging to 8% Of the residual electric quantity (State Of Charge, SOC) at 0.05C (0.05 times Of the battery capacity), and charging to 40% Of the SOC at 0.15C, thereby completing the formation treatment. And finally, carrying out secondary injection, and injecting the electrolyte with the volume of 20% of the required volume to obtain the potassium ion battery.
The battery capacity of the potassium ion battery of example 1 after capacity division at 1/3C and the battery capacity after 1500 cycles of charge and discharge at 1C were measured using carbon-coated potassium hexafluoroaluminate as a positive electrode additive for the potassium ion battery are recorded in table 1.
Comparative example 1
By K 2 CO 3 The powder was used instead of carbon-coated potassium hexafluoroaluminate, and the other steps were the same as in example 1. The battery capacity of the potassium ion battery of comparative example 1 after capacity division at 1/3C and the battery capacity after 1500 cycles of charge and discharge at 1C were tested and recorded in table 1.
Table 1 shows the battery capacities of the potassium ion batteries of example 1 and comparative example 1 after capacity division at 1/3C, and after 1500 cycles of charge and discharge at 1C.
Table 1 battery capacity after capacity division at 1/3C and battery capacity after 1500 cycles of charge and discharge cycles at 1C of the potassium ion batteries of example 1 and comparative example 1
| Sequence number | Capacity after 1/3C capacity division | 1C charge-discharge cycle 1500 cycles back volume |
| Example 1 | 342.5mA·h/g | 289mA·h/g |
| Comparative example 1 | 337mA·h/g | 265mA·h/g |
As shown in table 1, the battery capacity of the potassium ion battery in example 1 was larger than that of the potassium ion battery in comparative example 1 after capacity division at 1/3C. Meanwhile, after 1500 cycles of charge-discharge at 1C, the remaining capacity of the potassium-ion battery in example 1 was still greater than that in comparative example 1. The carbon-coated potassium hexafluoroaluminate can be used for extracting potassium ions preferentially to the positive electrode material when the battery is formed and charged for the first time, so that potassium ions consumed by forming an SEI film on the surface of a negative electrode are reduced, capacity reduction of a potassium ion battery and reduction of battery capacity after charge and discharge cycles are reduced, and the cycle stability of the potassium ion battery is improved.
In summary, the invention provides the positive electrode additive of the potassium ion battery, the preparation method and the application thereof, and the potassium ion battery is prepared by adding the prepared potassium hexafluoroaluminate into the positive electrode slurry, and the potassium hexafluoroaluminate is used as a positive electrode potassium supplement agent to compensate the first coulombic efficiency loss of the positive electrode and the negative electrode, thereby improving the energy density of the potassium ion battery and the cycling stability of the potassium ion battery. Meanwhile, the conductive performance and the corrosion resistance of the potassium hexafluoroaluminate are improved by carrying out carbon coating treatment on the potassium hexafluoroaluminate, so that the service life of the potassium ion battery is prolonged.
The above description is only a preferred embodiment of the present invention and the description of the technical principle applied, and it should be understood by those skilled in the art that the scope of the present invention is not limited to the specific combination of the above technical features, but also covers other technical features formed by any combination of the above technical features or the equivalent features thereof without departing from the inventive concept, for example, the technical features disclosed in the present invention (but not limited to) are replaced with technical features having similar functions. Other technical features besides those described in the specification are known to those skilled in the art, and are not repeated here for the purpose of highlighting the innovative features of the present invention.
Claims (10)
1. The positive electrode additive of the potassium ion battery is characterized by at least comprising potassium hexafluoroaluminate, wherein the potassium hexafluoroaluminate has a carbon coating structure.
2. The positive electrode additive for potassium ion battery according to claim 1, wherein the carbon coating amount of the positive electrode additive for potassium ion battery is 1% to 5%.
3. The positive electrode additive for a potassium ion battery according to claim 1, wherein the positive electrode additive for a potassium ion battery has a particle size of less than 30 μm.
4. A method of preparing the positive electrode additive for a potassium ion battery of any one of claims 1 to 3, comprising:
mixing a potassium source, an aluminum source and an acid solution in a solvent to obtain a mixed solution;
drying the mixed solution to form gel;
mixing the gel with a carbon material, and grinding to obtain powder particles; and
and sintering the powder particles under preset conditions, and grinding to obtain the carbon-coated potassium hexafluoroaluminate.
5. The method of preparing a positive electrode additive for a potassium ion battery according to claim 4, wherein the powder particles have a size of less than 5 μm.
6. The method of preparing a positive electrode additive for a potassium ion battery of claim 4, wherein said potassium source is selected from the group consisting of K 2 O、K 2 CO 3 、KOH、K 2 C 2 O 4 、KNO 3 、KCH 3 COO、K 2 SO 4 、K 2 SO 3 、KNO 2 、KS 2 O 3 、K 2 S 2 O 8 、KCl、K 3 PO 4 、KH 2 PO 4 、KClO 3 、KClO 4 、KSiO 3 NKF, KCN or K 3 [Fe(CN) 6 ]·H 2 And any one or more of O are mixed.
7. The method of preparing a positive electrode additive for a potassium ion battery of claim 4, wherein said aluminum source is selected from the group consisting of Al 2 O 3 、Al 2 (SO 4 ) 3 、AlCl 3 Or Al (NO) 3 ) 3 Any one or a mixture of a plurality of them.
8. The method for preparing the positive electrode additive of the potassium ion battery according to claim 4, wherein the carbon material is selected from any one or a mixture of a plurality of glucose, carbon nanotubes, graphene, graphite alkyne, soft carbon or hard carbon.
9. The method for preparing a positive electrode additive for a potassium ion battery according to claim 4, wherein the sintering temperature of the powder particles is 800-900 ℃ and the sintering time is 3-4 h.
10. An electrochemical device comprising at least a positive electrode, a negative electrode and a separator, wherein the positive electrode comprises the positive electrode additive for a potassium ion battery according to any one of claims 1 to 3.
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