CN114203991B - Positive electrode material additive, positive electrode and lithium ion battery - Google Patents
Positive electrode material additive, positive electrode and lithium ion battery Download PDFInfo
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- CN114203991B CN114203991B CN202111465549.4A CN202111465549A CN114203991B CN 114203991 B CN114203991 B CN 114203991B CN 202111465549 A CN202111465549 A CN 202111465549A CN 114203991 B CN114203991 B CN 114203991B
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- lithium iron
- phosphate
- lithium
- iron phosphate
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- 239000007774 positive electrode material Substances 0.000 title claims abstract description 87
- 239000000654 additive Substances 0.000 title claims abstract description 59
- 230000000996 additive effect Effects 0.000 title claims abstract description 59
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 25
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 25
- DVATZODUVBMYHN-UHFFFAOYSA-K lithium;iron(2+);manganese(2+);phosphate Chemical compound [Li+].[Mn+2].[Fe+2].[O-]P([O-])([O-])=O DVATZODUVBMYHN-UHFFFAOYSA-K 0.000 claims abstract description 70
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 claims abstract description 65
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 35
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 20
- 239000011258 core-shell material Substances 0.000 claims abstract description 13
- 239000010405 anode material Substances 0.000 claims abstract description 7
- 239000000463 material Substances 0.000 claims description 41
- 239000010410 layer Substances 0.000 claims description 33
- 239000011248 coating agent Substances 0.000 claims description 25
- 238000000576 coating method Methods 0.000 claims description 25
- 239000000243 solution Substances 0.000 claims description 22
- 238000001027 hydrothermal synthesis Methods 0.000 claims description 20
- 238000002360 preparation method Methods 0.000 claims description 18
- 239000000843 powder Substances 0.000 claims description 11
- 238000003756 stirring Methods 0.000 claims description 11
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 claims description 10
- 239000011261 inert gas Substances 0.000 claims description 9
- 229910021393 carbon nanotube Inorganic materials 0.000 claims description 8
- 239000002041 carbon nanotube Substances 0.000 claims description 8
- 238000001816 cooling Methods 0.000 claims description 8
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 8
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 7
- 239000011230 binding agent Substances 0.000 claims description 7
- 239000006258 conductive agent Substances 0.000 claims description 7
- 229910052744 lithium Inorganic materials 0.000 claims description 7
- 239000012266 salt solution Substances 0.000 claims description 7
- 229910003481 amorphous carbon Inorganic materials 0.000 claims description 6
- 239000000725 suspension Substances 0.000 claims description 6
- 229910021389 graphene Inorganic materials 0.000 claims description 5
- 239000000203 mixture Substances 0.000 claims description 5
- 229910015645 LiMn Inorganic materials 0.000 claims description 4
- 229910019142 PO4 Inorganic materials 0.000 claims description 4
- 239000011267 electrode slurry Substances 0.000 claims description 4
- 239000011247 coating layer Substances 0.000 claims description 3
- 239000003792 electrolyte Substances 0.000 claims description 3
- 229910000428 cobalt oxide Inorganic materials 0.000 abstract description 5
- IVMYJDGYRUAWML-UHFFFAOYSA-N cobalt(ii) oxide Chemical compound [Co]=O IVMYJDGYRUAWML-UHFFFAOYSA-N 0.000 abstract description 5
- 238000000034 method Methods 0.000 description 17
- 238000001291 vacuum drying Methods 0.000 description 13
- 238000002474 experimental method Methods 0.000 description 9
- 239000002245 particle Substances 0.000 description 8
- 239000002131 composite material Substances 0.000 description 7
- 238000002156 mixing Methods 0.000 description 6
- 230000035484 reaction time Effects 0.000 description 6
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 5
- 239000002033 PVDF binder Substances 0.000 description 5
- 239000011572 manganese Substances 0.000 description 5
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 5
- FTXWZTQWJZKPTB-UHFFFAOYSA-H [Li+].P(=O)([O-])([O-])[O-].[Mn+2].[Li+].P(=O)([O-])([O-])[O-].[Fe+2] Chemical compound [Li+].P(=O)([O-])([O-])[O-].[Mn+2].[Li+].P(=O)([O-])([O-])[O-].[Fe+2] FTXWZTQWJZKPTB-UHFFFAOYSA-H 0.000 description 4
- 239000002002 slurry Substances 0.000 description 4
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 3
- 239000013543 active substance Substances 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 238000007599 discharging Methods 0.000 description 3
- 235000003891 ferrous sulphate Nutrition 0.000 description 3
- 239000011790 ferrous sulphate Substances 0.000 description 3
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 3
- 238000011056 performance test Methods 0.000 description 3
- 238000000967 suction filtration Methods 0.000 description 3
- 238000005406 washing Methods 0.000 description 3
- 229910032387 LiCoO2 Inorganic materials 0.000 description 2
- 229910052493 LiFePO4 Inorganic materials 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- HFCVPDYCRZVZDF-UHFFFAOYSA-N [Li+].[Co+2].[Ni+2].[O-][Mn]([O-])(=O)=O Chemical compound [Li+].[Co+2].[Ni+2].[O-][Mn]([O-])(=O)=O HFCVPDYCRZVZDF-UHFFFAOYSA-N 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 229910021383 artificial graphite Inorganic materials 0.000 description 2
- 238000001354 calcination Methods 0.000 description 2
- 239000006229 carbon black Substances 0.000 description 2
- 239000007795 chemical reaction product Substances 0.000 description 2
- QHGJSLXSVXVKHZ-UHFFFAOYSA-N dilithium;dioxido(dioxo)manganese Chemical compound [Li+].[Li+].[O-][Mn]([O-])(=O)=O QHGJSLXSVXVKHZ-UHFFFAOYSA-N 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 239000012065 filter cake Substances 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 239000011259 mixed solution Substances 0.000 description 2
- 239000007773 negative electrode material Substances 0.000 description 2
- 239000011255 nonaqueous electrolyte Substances 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- NLHHRLWOUZZQLW-UHFFFAOYSA-N Acrylonitrile Chemical compound C=CC#N NLHHRLWOUZZQLW-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910012851 LiCoO 2 Inorganic materials 0.000 description 1
- 229910010594 LiFe1−yMnyPO4 Inorganic materials 0.000 description 1
- 229910000668 LiMnPO4 Inorganic materials 0.000 description 1
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- 239000006183 anode active material 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
- 239000011889 copper foil Substances 0.000 description 1
- 230000001351 cycling effect Effects 0.000 description 1
- 230000007123 defense Effects 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- ILXAVRFGLBYNEJ-UHFFFAOYSA-K lithium;manganese(2+);phosphate Chemical compound [Li+].[Mn+2].[O-]P([O-])([O-])=O ILXAVRFGLBYNEJ-UHFFFAOYSA-K 0.000 description 1
- 230000014759 maintenance of location Effects 0.000 description 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
- 239000011268 mixed slurry Substances 0.000 description 1
- 239000012452 mother liquor Substances 0.000 description 1
- 239000002105 nanoparticle Substances 0.000 description 1
- 238000007500 overflow downdraw method Methods 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 239000002985 plastic film Substances 0.000 description 1
- 229920006255 plastic film Polymers 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 238000007873 sieving Methods 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000001694 spray drying Methods 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
- 238000003466 welding 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
- H01M4/36—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
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- 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
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
- H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
-
- 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
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
- H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
- H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
-
- 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
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Composite Materials (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
The application discloses an anode material additive, an anode and a lithium ion battery. In the application, the positive electrode material additive has a core-shell structure, wherein the core-shell structure comprises an inner core, a first shell layer coated on the surface of the inner core and a second shell layer coated on the surface of the first shell layer; the inner core comprises lithium iron manganese phosphate; the first shell layer comprises lithium iron phosphate; the second shell layer includes carbon. After the lithium ion battery added with the positive electrode material additive disclosed by the first aspect of the application is mixed with the lithium iron phosphate and the lithium manganese iron phosphate by the cobalt oxide, the lithium iron phosphate and the lithium manganese iron phosphate which contain P-O bonds with high stability in a system are difficult to decompose, so that the safety and the stability are improved, and the chain reaction under thermal runaway can be inhibited to a certain extent, so that the safety performance of the battery core is improved.
Description
Technical Field
The embodiment of the invention relates to the field of lithium ion batteries, in particular to an anode material additive, an anode and a lithium ion battery.
Background
The lithium ion battery is used as a novel renewable green energy source, and has been widely applied to small electronic equipment (mobile phones, notebook computers and the like) by virtue of the advantages of high specific energy, high voltage, long cycle life, green pollution-free property and the like, and gradually becomes one of the most main candidate power sources of the electric automobile; in addition, the lithium ion battery is widely applied in the field of national defense and military, and covers various army equipment such as land, sea, air, sky and the like. With the progress of technology, people put higher demands on lithium ion batteries, and the search for high-performance lithium ion batteries has very important practical significance.
The performance of the positive and negative electrode materials of the lithium ion battery has very important influence on the finished battery, and the positive electrode material is a key factor for limiting the further improvement of the performance of the lithium ion battery, so that the search for the positive electrode material of the lithium ion battery with high performance is very important. The existing positive electrode material is easy to generate thermal runaway chain reaction, so that safety experiments such as needling overcharge are difficult to carry out, and the safety performance of the battery cell cannot be guaranteed. To solve this problem, attempts have been made in the prior art to mix a small amount of LFMP (LiFe 1-yMnyPO4 (0.5. Ltoreq. Y < 1.0) positive electrode material) to achieve suppression of the chain reaction under thermal runaway of the positive electrode material to some extent. For example:
Therefore, there is still a need in the art to find a positive electrode material that has high safety and can inhibit the dissolution of Mn 2+ and Fe 3+ during cycling.
Disclosure of Invention
The invention aims to provide a positive electrode material additive, so that the safety performance and the electrochemical performance of a lithium ion battery prepared by using the positive electrode material additive are improved.
Another object of the present invention is to provide a positive electrode.
Another object of the present invention is to provide a lithium ion battery.
Another object of the present invention is to provide a method for preparing the positive electrode material additive.
In order to solve the technical problems, the first aspect of the invention provides a positive electrode material additive, which is provided with a core-shell structure, wherein the core-shell structure comprises a core, a first shell layer coated on the surface of the core and a second shell layer coated on the surface of the first shell layer;
The inner core comprises lithium iron manganese phosphate;
The first shell layer comprises lithium iron phosphate;
The second shell layer includes carbon.
In some preferred embodiments, the core-shell structure is composed of an inner core, a first shell layer coated on the surface of the inner core, and a second shell layer coated on the surface of the first shell layer;
The inner core is lithium iron manganese phosphate;
The first shell layer is lithium iron phosphate;
The second shell layer is carbon.
In some preferred embodiments, the lithium iron manganese phosphate is LiMn xFe1-xPO4, where x ranges from 0.2 to 0.8 (SOC 7/3), preferably from 0.5 to 0.7 (SOC 7/3), for example 0.7 (SOC 7/3).
In some preferred embodiments, the mass of the lithium iron manganese phosphate is 70 to 99% of the total mass of the positive electrode material additive; more preferably 80 to 90%.
In some preferred embodiments, the lithium iron phosphate comprises 1 to 15% by mass of the total mass of the positive electrode material additive.
In some preferred embodiments, the mass of the carbon is 2 to 10% of the total mass of the positive electrode material additive.
In some preferred embodiments, the lithium manganese iron phosphate has a D50 of 2 to 50 μm; preferably from 2 to 20. Mu.m.
In some preferred schemes, the specific surface area of the lithium iron manganese phosphate is more than or equal to 10.0m 2/g.
In some preferred embodiments, the preparation of the positive electrode material additive comprises the steps of:
and coating carbon source powder on the lithium iron manganese phosphate material coated with the lithium iron phosphate on the surface through a coating reaction to obtain the anode material additive.
In some preferred embodiments, the coating reaction comprises the steps of: roasting and cooling.
The temperature of the firing is not lower than 400 ℃ and not higher than 1000 ℃, preferably not lower than 500 ℃ and not higher than 800 ℃, more preferably not lower than 600 ℃ and not higher than 750 ℃, for example: 600-750 ℃.
The time of the calcination is not less than 1 hour and not more than 10 hours, more preferably not less than 2 hours and not more than 8 hours, for example, 4 to 6 hours.
The cooling cools the material at least to a temperature not higher than t, wherein 200 ℃ gtoreq.t.gtoreq.room temperature (room temperature 23 to 26 ℃, e.g. 25 ℃), more preferably 150 ℃ gtoreq.t.gtoreq.room temperature, e.g. 25 to 150 ℃.
In some preferred embodiments, the carbon source powder is selected from at least one of amorphous carbon, carbon nanotubes, and graphene.
In some preferred embodiments, the coating reaction is performed in the presence of an inert gas.
In some preferred embodiments, the temperature of the coating reaction is not less than 400 ℃ and not more than 1000 ℃, preferably not less than 500 ℃ and not more than 800 ℃, more preferably not less than 600 ℃ and not more than 750 ℃, for example: 600-750 ℃.
In some preferred embodiments, the coating reaction is for a period of time not less than 1 hour and not more than 10 hours, more preferably not less than 2 hours and not more than 8 hours, for example 4 to 6 hours.
In some preferred embodiments, the preparation of the lithium iron manganese phosphate material with the surface coated with lithium iron phosphate comprises the steps of:
And carrying out hydrothermal reaction on a reaction solution containing lithium iron manganese phosphate and lithium iron phosphate to obtain the lithium iron manganese phosphate material with the surface coated with the lithium iron phosphate.
In some preferred embodiments, the reaction temperature is 150-180 ℃, more preferably 160 ℃.
In some preferred embodiments, the reaction pressure is from 0.48 to 1.0Mpa, more preferably 0.6Mpa.
In some preferred embodiments, in the reaction solution, the mass ratio of the lithium iron manganese phosphate to the lithium iron phosphate is 1:9 to 4:6, more preferably 2:8.
In some preferred embodiments, the reaction solution further comprises a ferrous salt solution; such as a ferrous sulfate solution.
In some preferred embodiments, the hydrothermal reaction time is not less than 3 hours and not more than 60 hours, more preferably, the hydrothermal reaction time is not less than 5 hours and not more than 50 hours, and even more preferably, the hydrothermal reaction time is not less than 10 hours and not more than 36 hours.
In some preferred embodiments, the preparation of the lithium iron manganese phosphate material with the surface coated with lithium iron phosphate comprises the steps of:
And (3) dropwise adding a ferrous salt solution into the suspension mixed with the lithium iron manganese phosphate and the lithium iron phosphate solution in the presence of inert gas, stirring, and then placing the mixture into a high-pressure reaction kettle with the temperature of 150-180 ℃ and the pressure of 0.48-1.0 Mpa for hydrothermal reaction to obtain the lithium iron manganese phosphate material with the surface coated with the lithium iron phosphate.
In some preferred embodiments, the hydrothermal reaction further comprises a post-treatment step:
and carrying out suction filtration, washing and vacuum drying on the hydrothermal reaction product.
In some preferred embodiments, the temperature of the vacuum drying is not less than 70 ℃ and not more than 160 ℃; more preferably, the temperature of the vacuum drying is not lower than 80 ℃ and not higher than 120 ℃.
In some preferred embodiments, the time of the vacuum drying is not less than 1 hour and not more than 60 hours; more preferably, the time of the vacuum drying is not less than 2 hours and not more than 50 hours; more preferably, the time of the vacuum drying is not less than 3 hours and not more than 36 hours.
The second aspect of the present invention provides a positive electrode coated on a surface of a current collector with a positive electrode slurry including a positive electrode active material, a conductive agent, and a binder;
Wherein the positive electrode active material includes a positive electrode active material and the positive electrode material additive.
In some preferred embodiments, the mass ratio of the positive electrode active material to the positive electrode material additive is (90.0 to 99.9): 0.1 to 10.0, more preferably: (95.0 to 99.0): (1.0 to 5.0), for example: 99:1.
In some preferred embodiments, the positive electrode active material is selected from at least one of lithium cobaltate, lithium manganate, and lithium nickel cobalt manganate; lithium cobaltate is preferred.
In some preferred embodiments, the mass ratio of the positive electrode active material, the conductive agent, and the binder is l: m: n, where l is 95 to 99, m is 0.5 to 3, and n is 1 to 5, e.g.: 96:1.5:2.5.
In some preferred embodiments, the D50 of the positive electrode active material is 5 to 10um; more preferably 6 to 8 μm, for example 8 μm.
In some preferred embodiments, the specific surface area of the positive electrode active material is not less than 2.0m 2/g, more preferably 2.0 to 6.0m 2/g; for example 4.2m 2/g.
In some preferred embodiments, the conductive agent is carbon nanotubes, carbon black, graphite, or graphene.
In some preferred embodiments, the carbon nanotubes have a specific surface area of 200-300m 2/g.
In some preferred embodiments, the binder is PVDF, SBR, or PAA.
In some preferred embodiments, the PVDF has a specific surface area of 40-70m 2/g; more preferably 60-65. Mu.m.
The third aspect of the invention provides a lithium ion battery comprising the positive electrode, the negative electrode, the electrolyte and the separator provided in the second aspect of the invention.
According to a fourth aspect of the present invention, there is provided a method for preparing the positive electrode material additive according to the first aspect of the present invention, the method comprising the steps of:
Preparing a lithium iron manganese phosphate material coated with lithium iron phosphate on the surface; and
And coating carbon source powder on the lithium iron manganese phosphate material with the surface coated with the lithium iron phosphate through a coating reaction. In some preferred embodiments, the step of preparing a surface-coated lithium iron phosphate lithium manganese phosphate material comprises:
and carrying out hydrothermal reaction on the reaction solution containing the lithium iron manganese phosphate and the lithium iron phosphate to obtain the lithium iron manganese phosphate material with the surface coated with the lithium iron phosphate.
In some preferred embodiments, the step of preparing a surface-coated lithium iron phosphate lithium manganese phosphate material comprises: and (3) dropwise adding a ferrous salt solution into the suspension mixed with the lithium iron manganese phosphate and the lithium iron phosphate solution in the presence of inert gas, stirring, and then placing the mixture into a high-pressure reaction kettle with the temperature of 150-180 ℃ and the pressure of 0.48-1.0 Mpa for hydrothermal reaction to obtain the lithium iron manganese phosphate material with the surface coated with the lithium iron phosphate.
Compared with the prior art, the invention has at least the following advantages:
(1) According to the positive electrode material additive provided by the first aspect of the invention, the positive electrode material additive is added into the positive electrode material, the nano particles of the lithium iron manganese phosphate coated by the lithium iron phosphate are fixed on the surfaces of the particles of the cobalt oxide material by a mechanical fusion method to form a compact porous coating layer, so that the problem that the cobalt oxide material and the lithium manganese phosphate material are easy to segregate due to different densities when the mixed slurry of the cobalt oxide material and the lithium iron manganese phosphate material is obtained in a slurry mixing stage in the mixing process in the prior art is solved, the consistency of the positive electrode material is improved, and the material is easier to disperse;
(2) The positive electrode material additive provided by the first aspect of the invention has little influence on the capacity density of the battery;
(3) The lithium ion battery added with the positive electrode material additive disclosed by the first aspect of the invention has better multiplying power performance, good electric conductivity and small impedance;
(4) The anode material additive of the first aspect of the invention can inhibit Mn 2+ and Fe 3 + from dissolving out in the circulating process, even Mn 2+ can not be detected out, which is beneficial to the stability of battery voltage;
(5) After the lithium ion battery added with the positive electrode material additive disclosed by the first aspect of the invention is mixed with the lithium iron phosphate and the lithium manganese iron phosphate by the cobalt oxide, the lithium iron phosphate and the lithium manganese iron phosphate which contain P-O bonds with high stability in a system are difficult to decompose, so that the safety and the stability are improved, and the chain reaction under thermal runaway can be inhibited to a certain extent, so that the safety performance of the battery core is improved;
(6) LiFePO4 and lithium manganese iron phosphate particles can form a good solid solution according to any proportion, so that LiMnPO4 can be coated on the surfaces of the lithium manganese iron phosphate particles, and compared with pure lithium manganese iron phosphate particles, the lithium manganese iron phosphate particles coated with LiFePO4 are easier to coat carbon, lower in preparation cost, more uniform and compact in formed coating layer and better in battery cycle performance.
It is understood that within the scope of the present invention, the above-described technical features of the present invention and technical features specifically described below (e.g., in the examples) may be combined with each other to constitute new or preferred technical solutions. And are limited to a space, and are not described in detail herein.
Drawings
One or more embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings.
Fig. 1 is a graph showing the results of a battery needling warming experiment in comparative example 1 according to the present invention;
fig. 2 is a graph showing the results of the battery needling temperature increase experiment in example 4 according to the present invention.
Detailed Description
The inventor finds that the existing positive electrode material has poor safety performance, and Mn 2+ and Fe 3+ are dissolved out in the circulating process, so that the circulating performance of the battery is damaged. Therefore, the inventor develops a positive electrode material additive with a shell-core structure through detailed experiments, the positive electrode material additive is mixed with a positive electrode active substance, the dissolution of Mn 2+ and Fe 3+ in the battery circulation process can be greatly reduced, the circulation performance and the safety performance of the battery are improved, and in addition, the conductivity of a lithium ion battery prepared from a positive electrode containing the positive electrode material additive is also greatly improved.
Further, the inventors have found the mass of each shell layer of the positive electrode material additive of the above-mentioned shell-core structure; particle size and specific surface area of particles forming each shell layer; the method for preparing the shell-core structure has great influence on the performance of the finished battery, and the inventor speculates that the coating rate and the coating effect of the shell-core structure are different due to the process, so that the dynamic performance of the obtained positive electrode is different, and the circulation and the conductivity of the battery are further influenced.
Further, the inventors have found that the above-mentioned positive electrode material additive is different in compatibility with different positive electrode active materials, and even the same positive electrode active material, the difference in particle diameter, specific surface area and tap density affects its compatibility with the positive electrode material additive. On the basis of this, the inventors have conducted a large number of experiments, and found that the performance is best exhibited when the above positive electrode material additive and lithium cobaltate (positive electrode active material) are mixed. Further, the inventors have found that when the mass ratio of the above-described positive electrode material additive and positive electrode active material is different, the cycle and the conductivity of the resulting lithium ion battery are greatly different. Based on this, the inventors have conducted a lot of experiments, and found that the mass ratio of lithium cobaltate to the above positive electrode material additive is (90.0 to 99.9): 0.1 to 10.0, more preferably: (95.0 to 99.0): at a most preferred ratio of (1.0 to 5.0) to 99:1, the resulting battery exhibits optimum conductivity and cycle performance.
In some embodiments of the present invention, there is provided a positive electrode material additive having a core-shell structure including an inner core, a first shell layer coated on a surface of the inner core, and a second shell layer coated on a surface of the first shell layer;
The inner core comprises lithium iron manganese phosphate;
The first shell layer comprises lithium iron phosphate;
The second shell layer includes carbon.
In some preferred embodiments, the core-shell structure is composed of an inner core, a first shell layer coated on the surface of the inner core, and a second shell layer coated on the surface of the first shell layer;
The inner core is lithium iron manganese phosphate;
The first shell layer is lithium iron phosphate;
The second shell layer is carbon.
In some preferred embodiments, the lithium iron manganese phosphate is LiMn xFe1-xPO4, where x ranges from 0.2 to 0.8 (SOC 7/3), preferably from 0.5 to 0.7 (SOC 7/3), for example 0.7 (SOC 7/3).
In some preferred embodiments, the mass of the lithium iron manganese phosphate is 70 to 99% of the total mass of the positive electrode material additive; more preferably 80 to 90%.
In some preferred embodiments, the lithium iron phosphate comprises 1 to 15% by mass of the total mass of the positive electrode material additive.
In some preferred embodiments, the mass of the carbon is 2 to 10% of the total mass of the positive electrode material additive.
In some preferred embodiments, the lithium manganese iron phosphate has a D50 of 2 to 50 μm; preferably from 2 to 20. Mu.m.
In some preferred schemes, the specific surface area of the lithium iron manganese phosphate is more than or equal to 10.0m 2/g.
In some preferred embodiments, the preparation of the positive electrode material additive comprises the steps of:
and coating carbon source powder on the lithium iron manganese phosphate material coated with the lithium iron phosphate on the surface through a coating reaction to obtain the anode material additive.
In some preferred embodiments, the coating reaction comprises the steps of: roasting and cooling.
The temperature of the firing is not lower than 400 ℃ and not higher than 1000 ℃, preferably not lower than 500 ℃ and not higher than 800 ℃, more preferably not lower than 600 ℃ and not higher than 750 ℃, for example: 600-750 ℃.
The time of the calcination is not less than 1 hour and not more than 10 hours, more preferably not less than 2 hours and not more than 8 hours, for example, 4 to 6 hours.
The cooling cools the material at least to a temperature not higher than t, wherein 200 ℃ gtoreq.t.gtoreq.room temperature (room temperature 23 to 26 ℃, e.g. 25 ℃), more preferably 150 ℃ gtoreq.t.gtoreq.room temperature, e.g. 25 to 150 ℃.
In some preferred embodiments, the carbon source powder is selected from at least one of amorphous carbon, carbon nanotubes, and graphene.
In some preferred embodiments, the coating reaction is performed in the presence of an inert gas.
In some preferred embodiments, the temperature of the coating reaction is not less than 400 ℃ and not more than 1000 ℃, preferably not less than 500 ℃ and not more than 800 ℃, more preferably not less than 600 ℃ and not more than 750 ℃, for example: 600-750 ℃.
In some preferred embodiments, the coating reaction is for a period of time not less than 1 hour and not more than 10 hours, more preferably not less than 2 hours and not more than 8 hours, for example 4 to 6 hours.
In some preferred embodiments, the preparation of the lithium iron manganese phosphate material with the surface coated with lithium iron phosphate comprises the steps of:
And carrying out hydrothermal reaction on a reaction solution containing lithium iron manganese phosphate and lithium iron phosphate to obtain the lithium iron manganese phosphate material with the surface coated with the lithium iron phosphate.
In some preferred embodiments, the reaction temperature is 150-180 ℃, more preferably 160 ℃.
In some preferred embodiments, the reaction pressure is from 0.48 to 1.0Mpa, more preferably 0.6Mpa.
In some preferred embodiments, in the reaction solution, the mass ratio of the lithium iron manganese phosphate to the lithium iron phosphate is 1:9 to 4:6, more preferably 2:8.
In some preferred embodiments, the reaction solution further comprises a ferrous salt solution; such as a ferrous sulfate solution.
In some preferred embodiments, the hydrothermal reaction time is not less than 3 hours and not more than 60 hours, more preferably, the hydrothermal reaction time is not less than 5 hours and not more than 50 hours, and even more preferably, the hydrothermal reaction time is not less than 10 hours and not more than 36 hours.
In some preferred embodiments, the preparation of the lithium iron manganese phosphate material with the surface coated with lithium iron phosphate comprises the steps of:
And (3) dropwise adding a ferrous salt solution into the suspension mixed with the lithium iron manganese phosphate and the lithium iron phosphate solution in the presence of inert gas, stirring, and then placing the mixture into a high-pressure reaction kettle with the temperature of 150-180 ℃ and the pressure of 0.48-1.0 Mpa for hydrothermal reaction to obtain the lithium iron manganese phosphate material with the surface coated with the lithium iron phosphate.
In some preferred embodiments, the hydrothermal reaction further comprises a post-treatment step:
and carrying out suction filtration, washing and vacuum drying on the hydrothermal reaction product.
In some preferred embodiments, the temperature of the vacuum drying is not less than 70 ℃ and not more than 160 ℃; more preferably, the temperature of the vacuum drying is not lower than 80 ℃ and not higher than 120 ℃.
In some preferred embodiments, the time of the vacuum drying is not less than 1 hour and not more than 60 hours; more preferably, the time of the vacuum drying is not less than 2 hours and not more than 50 hours; more preferably, the time of the vacuum drying is not less than 3 hours and not more than 36 hours.
In some embodiments of the present invention, there is provided a positive electrode coated on a surface of a current collector with a positive electrode slurry including a positive electrode active material, a conductive agent, and a binder;
Wherein the positive electrode active material includes a positive electrode active material and the positive electrode material additive.
In some preferred embodiments, the mass ratio of the positive electrode active material to the positive electrode material additive is (90.0 to 99.9): 0.1 to 10.0, more preferably: (95.0 to 99.0): (1.0 to 5.0), for example: 99:1.
In some preferred embodiments, the positive electrode active material is selected from at least one of lithium cobaltate, lithium manganate, and lithium nickel cobalt manganate; lithium cobaltate is preferred.
In some preferred embodiments, the mass ratio of the positive electrode active material, the conductive agent, and the binder is l: m: n, where l is 95 to 99, m is 0.5 to 3, and n is 1 to 5, e.g.: 96:1.5:2.5.
In some preferred embodiments, the D50 of the positive electrode active material is 5 to 10um; more preferably 6 to 8 μm.
In some preferred embodiments, the specific surface area of the positive electrode active material is not less than 2.0m 2/g.
In some preferred embodiments, the conductive agent is carbon nanotubes, carbon black, graphite, or graphene.
In some preferred embodiments, the carbon nanotubes have a specific surface area of 200-300m 2/g.
In some preferred embodiments, the binder is PVDF, SBR, or PAA.
In some preferred embodiments, the PVDF has a specific surface area of 40-70m 2/g; more preferably 60-65. Mu.m.
In some embodiments of the invention there is provided a lithium ion battery comprising the positive electrode provided in the second aspect of the invention, a negative electrode, an electrolyte and a separator.
In some embodiments of the present invention, there is provided a method for preparing the positive electrode material additive according to the first aspect of the present invention, the method comprising the steps of:
Preparing a lithium iron manganese phosphate material coated with lithium iron phosphate on the surface; and
And coating carbon source powder on the lithium iron manganese phosphate material with the surface coated with the lithium iron phosphate through a coating reaction. In some preferred embodiments, the step of preparing a surface-coated lithium iron phosphate lithium manganese phosphate material comprises:
and carrying out hydrothermal reaction on the reaction solution containing the lithium iron manganese phosphate and the lithium iron phosphate to obtain the lithium iron manganese phosphate material with the surface coated with the lithium iron phosphate.
In some preferred embodiments, the step of preparing a surface-coated lithium iron phosphate lithium manganese phosphate material comprises: and (3) dropwise adding a ferrous salt solution into the suspension mixed with the lithium iron manganese phosphate and the lithium iron phosphate solution in the presence of inert gas, stirring, and then placing the mixture into a high-pressure reaction kettle with the temperature of 150-180 ℃ and the pressure of 0.48-1.0 Mpa for hydrothermal reaction to obtain the lithium iron manganese phosphate material with the surface coated with the lithium iron phosphate.
As used herein, unless otherwise indicated, "room temperature" refers to the temperature measured in a conventional laboratory using a celsius thermometer, preferably 23 to 26 ℃, such as 25 ℃ (kelvin being 298.15K).
The present invention will be further described with reference to specific embodiments in order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent. It is to be understood that these examples are illustrative of the present invention and are not intended to limit the scope of the present invention. The experimental methods, in which specific conditions are not noted in the following examples, are generally conducted under conventional conditions or under conditions recommended by the manufacturer. Percentages and parts are weight percentages and parts unless otherwise indicated. The experimental materials and reagents used in the following examples were obtained from commercial sources unless otherwise specified.
Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs, it is to be noted that the terms used herein are used merely to describe specific embodiments and are not intended to limit exemplary embodiments of the application.
Example 1 preparation of additive for three-layer core-shell cathode Material
(1) Preparation of lithium iron manganese phosphate (LiMn xFe1-x PO4, where X is between 0.2 and 0.8) material
Mixing lithium hydroxide aqueous solution, ferrous sulfate aqueous solution and phosphoric acid under stirring, sealing, heating to 150-180 ℃ within 0.5-2.0 hours, reacting for 0.5-4 hours under the pressure of 0.48-1.0 Mpa, cooling to below 80 ℃, and filtering to obtain a wet filter cake and mother liquor; drying the wet filter cake in air in a spray drying or flash drying mode to obtain lithium iron manganese phosphate powder; and discharging at the temperature below 150 ℃ to obtain the lithium iron manganese phosphate material.
(2) Lithium iron manganese phosphate composite material with surface coated with lithium iron phosphate
Step 1, weighing stoichiometry 7:3 LiOH H 2O、H3PO4 and FeSO 4·7H2 O are respectively dissolved in a proper amount of distilled water with the concentration of 1mol to prepare a lithium iron phosphate solution;
Step 2, adding a certain amount of 0.8mol of lithium iron manganese phosphate material into the prepared lithium iron phosphate solution, adding a proper amount of 0.05mol of dispersing agent, mixing, and fully stirring to uniformly disperse lithium iron manganese phosphate powder;
step 3, slowly dripping the lithium iron phosphate solution prepared in the step 1 into the rapidly stirred lithium iron manganese phosphate suspension;
Step 4, introducing protective gas into the mixed solution obtained in the step 3, introducing for 10-60 minutes, slowly dripping the FeSO 4·7H2 O solution prepared in the step 1 in a rapid stirring state, and rapidly stirring for 10-60 minutes;
step 5, pouring the mixed solution in the step 4 into a high-pressure reaction kettle, and placing the reaction kettle in an oven to react for 3-36 hours at a certain reaction temperature;
And 6, carrying out suction filtration and washing on the product in the step 5, and then carrying out vacuum drying at the temperature of 80-120 ℃ for 12-36 hours to obtain a lithium iron phosphate composite material with the surface coated with lithium iron phosphate, wherein the mass ratio of the lithium iron phosphate to the lithium iron phosphate in the obtained lithium iron phosphate composite material with the surface coated with the lithium iron phosphate is (60-90): (5-20).
(3) Preparation of three-layer core-shell positive electrode material additive
And (3) carrying out carbon coating on the lithium iron phosphate composite material with the surface coated with the lithium iron phosphate and carbon source composite powder (such as amorphous carbon), specifically carrying out mixing on the lithium iron phosphate composite material with the surface coated with the lithium iron phosphate and the amorphous carbon under the condition of inert gas (the mass ratio of the lithium iron phosphate composite material with the surface coated with the lithium iron phosphate to the amorphous carbon is (85-99) (1-15), roasting for 4-6 hours at 600-750 ℃, cooling to below 150 ℃, discharging, and sieving through a granulating procedure to obtain the three-layer core-shell anode material additive.
The method of preparing the positive electrode material additive in example 2 and example 3 was substantially the same as in example 1, except that the mass ratio of each layer of the three-layer core-shell positive electrode material additive was different, as shown in table 1.
TABLE 1
Example 4 preparation of Positive electrode sheet (D50 is 8 um)
Taking LiCoO2 with the D50 of 8um, the tap density of 2.2g/cm & lt 3 & gt and the specific surface area of 4.2m 2/g as a positive electrode active substance, dissolving the LiCoO2 into N-methylpyrrolidone solvent according to the proportion of 96% of positive electrode active substance (based on positive electrode mass), 2.5% of PVDF (based on positive electrode mass) and 1.5% of carbon nano tube (based on positive electrode mass), vacuumizing in a stirrer, stirring, mixing and dispersing to prepare uniform bubble-free slurry, adding the positive electrode material additive prepared in the first embodiment, wherein the mass ratio of the positive electrode material additive to LiCoO 2 is 1:99, and uniformly coating on an aluminum foil to prepare the positive electrode sheet.
In other examples and comparative examples, the method of preparing the positive electrode sheet was substantially the same as in example 4, except that each component and the amount of each component in the positive electrode sheet were different, as shown in table 2.
TABLE 2
Preparation of lithium ion batteries
(1) Preparation of negative electrode plate
Artificial graphite is used as a negative electrode active material, wherein the artificial graphite is aligned with I (002)/I (110) =4.8, the D50 is 6.5um, and the specific surface area is 2.1m 2/g. The preparation method comprises the steps of dissolving 94% of anode active material (based on anode mass), 2.8% of acrylonitrile multipolymer (based on anode mass) and 3.2% of conductive carbon black (based on anode mass) in deionized water, vacuumizing in a stirrer, stirring and dispersing to prepare uniform bubble-free slurry, and uniformly coating the slurry on copper foil to prepare the anode piece.
(2) Packaging and formation
The positive electrode plate, the diaphragm and the negative electrode plate prepared in the embodiment 4 are prepared into a battery cell in a lamination mode, the battery cell is provided with electrode lugs at the same side, the electrode lugs and a current collector are welded together by an ultrasonic welding machine, and then the battery cell is packaged by an aluminum plastic film.
And after baking the battery core, injecting the nonaqueous electrolyte into the battery core, and preparing the 4Ah lithium ion battery after the nonaqueous electrolyte is formed into a volume fraction.
The positive electrode sheets of examples 5 to 4 in table 2 above were prepared into lithium ion batteries according to the above-described battery preparation method for battery performance test.
Test case
The cell needling temperature rise test and the battery performance test were performed according to the following methods, and the results are recorded in table 3 below.
[ Electric core needling heating experiment method ]
(1) Charging the experimental battery to 4.2V with a constant current and a constant voltage of 1C until the current is 0.02C;
(2) The steel needle is penetrated from the direction vertical to the electrode plate of the electric core at the speed of (25+/-5) mm/s by using a height Wen Gangzhen (cone angle of needle tip is 45-60 degrees, needle surface is smooth and clean; rust-free; oxide layer and greasy dirt) of phi 5-8 mm, the penetrating position is preferably close to the geometric center of the penetrated surface, and the steel needle is remained in the electric core;
(3) Observing for 1h, and recording the state and temperature rise of the battery cell.
The results of the cell needling experiments of example 4 are shown in fig. 2, and those of the comparative example are shown in fig. 1. As can be seen from a comparison of fig. 1 and 2, the battery to which the positive electrode material additive according to the present invention is added is less prone to thermal runaway.
[ Battery Performance test method ]
(1) Charging the experimental battery cell to 4.2V at the constant current and constant voltage of 0.5C of the battery cell under the condition of 25+/-3 ℃ until the current is 0.02C;
(2) Standing for 30min;
(3) Under the condition of 25+/-3 ℃, discharging the 1C constant current to 3.0V, and recording the capacity D1 at the moment;
(4) Standing for 30min;
(5) Charging the battery cell to 4.2V at constant current and constant voltage under the condition of 25+/-3 ℃ until the current is 0.02 ℃;
(6) Placing for 20h at-40+/-3 ℃;
(7) 5C is discharged to 3.0V, and the capacity D2 is recorded at the moment;
the capacity retention d=d2/d1 is 100%.
TABLE 3 Table 3
It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples of carrying out the invention and that various changes in form and details may be made therein without departing from the spirit and scope of the invention.
Claims (9)
1. A positive electrode, wherein the positive electrode is coated on the surface of a current collector by a positive electrode slurry, and the positive electrode slurry comprises a positive electrode active material, a conductive agent and a binder;
The positive electrode active material comprises a positive electrode active material and a positive electrode material additive, wherein the positive electrode material additive is of a core-shell structure, and the core-shell structure comprises an inner core, a first shell layer coated on the surface of the inner core and a second shell layer coated on the surface of the first shell layer;
The inner core comprises lithium iron manganese phosphate;
The first shell layer comprises lithium iron phosphate;
the second shell layer comprises carbon;
wherein the positive electrode active material is lithium cobaltate;
The positive electrode active material additive is fixed on the surface of the positive electrode active material to form a porous coating layer;
The mass ratio of the positive electrode active material to the positive electrode material additive is (90.0 to 99.9): 0.1 to 5.0.
2. The positive electrode of claim 1, wherein the lithium iron manganese phosphate is LiMn xFe1-xPO4, wherein x ranges from 0.2 to 0.8.
3. The positive electrode according to claim 1, wherein the mass of the lithium iron manganese phosphate is 70 to 99% of the total mass of the positive electrode material additive;
And/or, the mass of the lithium iron phosphate accounts for 1 to 15% of the total mass of the positive electrode material additive;
and/or, the mass of the carbon is 2 to 10% of the total mass of the positive electrode material additive;
and/or the D50 of the lithium manganese iron phosphate is 2 to 50 μm;
And/or the specific surface area of the lithium iron manganese phosphate is more than or equal to 10.0 m 2/g.
4. The positive electrode according to claim 1, wherein the preparation of the positive electrode material additive comprises the steps of:
and coating carbon source powder on the lithium iron manganese phosphate material coated with the lithium iron phosphate on the surface through a coating reaction to obtain the anode material additive.
5. The positive electrode according to claim 4, wherein the coating reaction comprises the steps of: roasting and cooling;
And/or, the coating reaction is carried out in the presence of an inert gas;
And/or the carbon source powder is selected from at least one of amorphous carbon, carbon nanotubes and graphene.
6. The positive electrode according to claim 5, wherein the baking temperature is not lower than 400 ℃ and not higher than 1000 ℃;
and/or, the roasting time is not less than 1 hour and not more than 10 hours;
And/or, the cooling cools the material at least until the temperature of the material is not higher than t, wherein 200 ℃ is not less than t is not less than room temperature, and the room temperature is 23-26 ℃.
7. The positive electrode according to claim 4, wherein the preparation of the lithium iron manganese phosphate material coated with lithium iron phosphate on the surface comprises the steps of:
And carrying out hydrothermal reaction on the reaction solution containing the lithium iron manganese phosphate and the lithium iron phosphate to obtain the lithium iron manganese phosphate material with the surface coated with the lithium iron phosphate.
8. The positive electrode according to claim 4, wherein the preparation of the lithium iron manganese phosphate material coated with lithium iron phosphate on the surface comprises the steps of:
And (3) dropwise adding a ferrous salt solution into the suspension mixed with the lithium iron manganese phosphate and the lithium iron phosphate solution in the presence of inert gas, stirring, and then placing the mixture into a high-pressure reaction kettle with the temperature of 150-180 ℃ and the pressure of 0.48-1.0 Mpa for hydrothermal reaction to obtain the lithium iron manganese phosphate material with the surface coated with the lithium iron phosphate.
9. A lithium ion battery comprising the positive electrode, the negative electrode, the electrolyte, and the separator according to any one of claims 1 to 8.
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Citations (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102010006077A1 (en) * | 2010-01-28 | 2011-08-18 | Süd-Chemie AG, 80333 | Substituted lithium manganese metal phosphate |
WO2014077274A1 (en) * | 2012-11-14 | 2014-05-22 | 古河電気工業株式会社 | Positive electrode active material, production method for same, positive electrode for non-aqueous electrolyte secondary cell, and non-aqueous electrolyte secondary cell |
CN105810897A (en) * | 2014-12-31 | 2016-07-27 | 比亚迪股份有限公司 | Lithium ion battery composite material and preparation method thereof, and positive electrode material including composite material |
CN105990562A (en) * | 2015-02-11 | 2016-10-05 | 中国科学院宁波材料技术与工程研究所 | Nanometer lithium iron manganese phosphate composite material with core-shell structure, and preparation method and application thereof |
CN106340639A (en) * | 2016-10-28 | 2017-01-18 | 合肥国轩高科动力能源有限公司 | Lithium iron phosphate/carbon-coated core-shell lithium manganese iron phosphate composite cathode material and preparation method thereof |
CN106935808A (en) * | 2015-12-31 | 2017-07-07 | 比亚迪股份有限公司 | Positive electrode active materials and preparation method thereof and cell size and positive pole and lithium battery |
CN107546379A (en) * | 2017-08-18 | 2018-01-05 | 宁波知能新材料有限公司 | Iron manganese phosphate for lithium ternary material composite positive pole and preparation method thereof |
CN107895781A (en) * | 2017-10-27 | 2018-04-10 | 深圳市沃特玛电池有限公司 | A kind of composite positive pole of lithium ion battery and preparation method thereof |
CN109417162A (en) * | 2018-09-28 | 2019-03-01 | 宁波致良新能源有限公司 | Anode additive and preparation method thereof, anode and preparation method thereof and lithium ion battery |
CN110444744A (en) * | 2019-07-09 | 2019-11-12 | 上海华普汽车有限公司 | A kind of lithium battery composite positive pole and lithium battery preparation method |
CN110459749A (en) * | 2019-08-21 | 2019-11-15 | 中国科学院宁波材料技术与工程研究所 | A kind of composite positive pole and preparation method thereof |
CN110993894A (en) * | 2019-11-25 | 2020-04-10 | 宁波致良新能源有限公司 | Positive electrode additive and preparation method thereof, positive electrode and preparation method thereof, and lithium ion battery |
CN111740100A (en) * | 2020-05-25 | 2020-10-02 | 银隆新能源股份有限公司 | Positive electrode slurry and lithium ion battery |
CN112864360A (en) * | 2019-11-28 | 2021-05-28 | 珠海冠宇电池股份有限公司 | High-voltage positive pole piece and lithium ion secondary battery containing same |
-
2021
- 2021-12-01 CN CN202111465549.4A patent/CN114203991B/en active Active
Patent Citations (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102010006077A1 (en) * | 2010-01-28 | 2011-08-18 | Süd-Chemie AG, 80333 | Substituted lithium manganese metal phosphate |
WO2014077274A1 (en) * | 2012-11-14 | 2014-05-22 | 古河電気工業株式会社 | Positive electrode active material, production method for same, positive electrode for non-aqueous electrolyte secondary cell, and non-aqueous electrolyte secondary cell |
CN105810897A (en) * | 2014-12-31 | 2016-07-27 | 比亚迪股份有限公司 | Lithium ion battery composite material and preparation method thereof, and positive electrode material including composite material |
CN105990562A (en) * | 2015-02-11 | 2016-10-05 | 中国科学院宁波材料技术与工程研究所 | Nanometer lithium iron manganese phosphate composite material with core-shell structure, and preparation method and application thereof |
CN106935808A (en) * | 2015-12-31 | 2017-07-07 | 比亚迪股份有限公司 | Positive electrode active materials and preparation method thereof and cell size and positive pole and lithium battery |
CN106340639A (en) * | 2016-10-28 | 2017-01-18 | 合肥国轩高科动力能源有限公司 | Lithium iron phosphate/carbon-coated core-shell lithium manganese iron phosphate composite cathode material and preparation method thereof |
CN107546379A (en) * | 2017-08-18 | 2018-01-05 | 宁波知能新材料有限公司 | Iron manganese phosphate for lithium ternary material composite positive pole and preparation method thereof |
WO2019034105A1 (en) * | 2017-08-18 | 2019-02-21 | 宁波致良新能源有限公司 | Positive electrode material and preparation method thereof, positive electrode and lithium ion battery |
CN107895781A (en) * | 2017-10-27 | 2018-04-10 | 深圳市沃特玛电池有限公司 | A kind of composite positive pole of lithium ion battery and preparation method thereof |
CN109417162A (en) * | 2018-09-28 | 2019-03-01 | 宁波致良新能源有限公司 | Anode additive and preparation method thereof, anode and preparation method thereof and lithium ion battery |
CN110444744A (en) * | 2019-07-09 | 2019-11-12 | 上海华普汽车有限公司 | A kind of lithium battery composite positive pole and lithium battery preparation method |
CN110459749A (en) * | 2019-08-21 | 2019-11-15 | 中国科学院宁波材料技术与工程研究所 | A kind of composite positive pole and preparation method thereof |
CN110993894A (en) * | 2019-11-25 | 2020-04-10 | 宁波致良新能源有限公司 | Positive electrode additive and preparation method thereof, positive electrode and preparation method thereof, and lithium ion battery |
CN112864360A (en) * | 2019-11-28 | 2021-05-28 | 珠海冠宇电池股份有限公司 | High-voltage positive pole piece and lithium ion secondary battery containing same |
CN111740100A (en) * | 2020-05-25 | 2020-10-02 | 银隆新能源股份有限公司 | Positive electrode slurry and lithium ion battery |
Non-Patent Citations (3)
Title |
---|
A phytic acid derived LiMn0.5Fe0.5PO4/Carbon composite of high energy density for lithium rechargeable batteries;Yan Meng等;Scientific Reports;20190430;第9卷;第6665-(1-11)页 * |
磷酸铁锰锂正极材料的制备及性能研究进展;赵秋萍等;化工新型材料;20160915;第44卷(第09期);第53-55页 * |
锂离子电池正极材料的产业化现状与发展趋势;胡国荣;第一届全国储能科学与技术大会摘要集;20141231;第11-12页 * |
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