CN112186158A - Positive electrode composite material and preparation method and application thereof - Google Patents
Positive electrode composite material and preparation method and application thereof Download PDFInfo
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- 239000002131 composite material Substances 0.000 title claims abstract description 101
- 238000002360 preparation method Methods 0.000 title claims description 26
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 118
- 229910021389 graphene Inorganic materials 0.000 claims abstract description 57
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 50
- 239000007774 positive electrode material Substances 0.000 claims abstract description 40
- 239000010405 anode material Substances 0.000 claims abstract description 21
- 239000002245 particle Substances 0.000 claims abstract description 13
- 239000011247 coating layer Substances 0.000 claims abstract description 3
- 239000002002 slurry Substances 0.000 claims description 27
- 238000002156 mixing Methods 0.000 claims description 20
- 238000001694 spray drying Methods 0.000 claims description 19
- 238000003756 stirring Methods 0.000 claims description 19
- 238000000034 method Methods 0.000 claims description 16
- 239000002270 dispersing agent Substances 0.000 claims description 12
- 229910021393 carbon nanotube Inorganic materials 0.000 claims description 10
- 239000002041 carbon nanotube Substances 0.000 claims description 10
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims description 8
- 229910001416 lithium ion Inorganic materials 0.000 claims description 8
- 239000002904 solvent Substances 0.000 claims description 8
- 239000002033 PVDF binder Substances 0.000 claims description 7
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 7
- 229920000128 polypyrrole Polymers 0.000 claims description 7
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 7
- 229920000036 polyvinylpyrrolidone Polymers 0.000 claims description 7
- 239000001267 polyvinylpyrrolidone Substances 0.000 claims description 7
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 claims description 7
- 229920002134 Carboxymethyl cellulose Polymers 0.000 claims description 6
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 6
- 230000002572 peristaltic effect Effects 0.000 claims description 6
- 239000004372 Polyvinyl alcohol Substances 0.000 claims description 5
- 239000001768 carboxy methyl cellulose Substances 0.000 claims description 5
- 235000010948 carboxy methyl cellulose Nutrition 0.000 claims description 5
- 239000008112 carboxymethyl-cellulose Substances 0.000 claims description 5
- 238000002347 injection Methods 0.000 claims description 5
- 239000007924 injection Substances 0.000 claims description 5
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- 238000004519 manufacturing process Methods 0.000 claims description 4
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- 238000000576 coating method Methods 0.000 abstract description 11
- 239000000463 material Substances 0.000 abstract description 9
- 230000009286 beneficial effect Effects 0.000 abstract description 5
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- 238000007086 side reaction Methods 0.000 abstract description 3
- 230000000052 comparative effect Effects 0.000 description 29
- 239000010406 cathode material Substances 0.000 description 13
- 238000012360 testing method Methods 0.000 description 10
- 230000014759 maintenance of location Effects 0.000 description 7
- 239000000843 powder Substances 0.000 description 7
- 229910013716 LiNi Inorganic materials 0.000 description 6
- 239000007789 gas Substances 0.000 description 6
- 238000010438 heat treatment Methods 0.000 description 6
- 239000011572 manganese Substances 0.000 description 6
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 5
- 239000000523 sample Substances 0.000 description 4
- OMOVVBIIQSXZSZ-UHFFFAOYSA-N [6-(4-acetyloxy-5,9a-dimethyl-2,7-dioxo-4,5a,6,9-tetrahydro-3h-pyrano[3,4-b]oxepin-5-yl)-5-formyloxy-3-(furan-3-yl)-3a-methyl-7-methylidene-1a,2,3,4,5,6-hexahydroindeno[1,7a-b]oxiren-4-yl] 2-hydroxy-3-methylpentanoate Chemical compound CC12C(OC(=O)C(O)C(C)CC)C(OC=O)C(C3(C)C(CC(=O)OC4(C)COC(=O)CC43)OC(C)=O)C(=C)C32OC3CC1C=1C=COC=1 OMOVVBIIQSXZSZ-UHFFFAOYSA-N 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 239000013543 active substance Substances 0.000 description 2
- 238000010280 constant potential charging Methods 0.000 description 2
- 238000010277 constant-current charging Methods 0.000 description 2
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- 238000011161 development Methods 0.000 description 2
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- 101100317222 Borrelia hermsii vsp3 gene Proteins 0.000 description 1
- NIPNSKYNPDTRPC-UHFFFAOYSA-N N-[2-oxo-2-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)ethyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C(CNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 NIPNSKYNPDTRPC-UHFFFAOYSA-N 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 1
- NXPZICSHDHGMGT-UHFFFAOYSA-N [Co].[Mn].[Li] Chemical compound [Co].[Mn].[Li] NXPZICSHDHGMGT-UHFFFAOYSA-N 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000000498 ball milling Methods 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 238000007600 charging Methods 0.000 description 1
- QHGJSLXSVXVKHZ-UHFFFAOYSA-N dilithium;dioxido(dioxo)manganese Chemical compound [Li+].[Li+].[O-][Mn]([O-])(=O)=O QHGJSLXSVXVKHZ-UHFFFAOYSA-N 0.000 description 1
- 229910001873 dinitrogen Inorganic materials 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000005672 electromagnetic field Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
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- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 1
- FRMOHNDAXZZWQI-UHFFFAOYSA-N lithium manganese(2+) nickel(2+) oxygen(2-) Chemical compound [O-2].[Mn+2].[Ni+2].[Li+] FRMOHNDAXZZWQI-UHFFFAOYSA-N 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 229910001463 metal phosphate Inorganic materials 0.000 description 1
- 238000001000 micrograph Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910021392 nanocarbon Inorganic materials 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 239000010450 olivine Substances 0.000 description 1
- 229910052609 olivine Inorganic materials 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 238000001878 scanning electron micrograph Methods 0.000 description 1
- 229910052596 spinel Inorganic materials 0.000 description 1
- 239000011029 spinel Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/362—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
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—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
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—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
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- 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
- H01M4/624—Electric conductive fillers
- H01M4/625—Carbon or graphite
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- H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
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- H01M4/02—Electrodes composed of, or comprising, active material
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/028—Positive electrodes
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- 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
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Abstract
The invention relates to a positive electrode composite material, which comprises a cobalt-free positive electrode material and a composite carbon coating layer formed on the surface of the cobalt-free positive electrode material, wherein the particle size of the cobalt-free positive electrode material is 3-5 mu m, and the cobalt-free positive electrode material with the particle size within the range is more beneficial to coating composite carbon. The graphene is selected from the composite carbon, so that the ionic conductivity of the cobalt-free anode material can be effectively improved, the anode composite material can also effectively isolate electrolyte, the occurrence of side reactions is reduced, and the first charge-discharge capacity of the material is improved.
Description
Technical Field
The invention relates to the field of lithium ion batteries, in particular to a positive electrode composite material and a preparation method and application thereof.
Background
With the development of new energy automobiles, lithium ion power batteries are receiving attention as the hottest power batteries of electric vehicles. The development of a commercial graphite cathode which is mature and stable relatively is particularly urgent for the research and development of a cathode material which has high capacity, long service life, low cost, safety and environmental protection. Currently, commercially available lithium battery positive electrode materials mainly include lithium cobaltate with a layered structure, ternary materials, lithium manganate with a spinel structure, lithium iron phosphate with an olivine structure and cobalt-free positive electrode materials. The positive electrode material has the advantages of high specific capacity, energy density and power density and low cost, but the electrochemical performance, thermal stability and structural stability of the positive electrode material need to be further improved, and particularly, the problems are particularly obvious along with the improvement of nickel content under high-temperature and high-potential test environments. Therefore, it is important to modify the positive electrode material.
The current coating of the commercial positive electrode material comprises carbon, metal oxide, phosphate and anions, and although the coating prevents the direct contact of the lithium nickel manganese oxide material and the electrolyte, the coating has the problems of reducing specific capacity, corroding the surface of the material, increasing resistance and the like. The graphene is a two-dimensional sheet nano carbon material, and has excellent thermal, mechanical, optical and electrical properties and wide application prospects.
CN104538620A discloses a preparation method of a fluorinated graphene coated manganese cobalt lithium cathode material, in which ultrasonically dispersed fluorinated graphene and an active substance are stirred, and then subjected to centrifugal heat treatment to obtain a graphene coated product. The technology has the biggest defects that: because the specific surface of graphene is very large and is easy to agglomerate, simple stirring and centrifugal heat treatment cannot enable the graphene to be uniformly coated on the surface of the positive electrode material.
CN104393282A discloses a preparation method for mixing graphene and a positive electrode material by means of planetary ball milling, and then sintering the mixture at the constant temperature of 800 ℃ for 10-15h by heat treatment of high-purity nitrogen gas to obtain the graphene-coated multi-element positive electrode material. The drawbacks of this technique are: the oxidation problem of graphene is well avoided in the high-purity nitrogen environment of heat treatment, but the performance of the material is seriously influenced by the anode material which is synthesized by sintering in the oxygen environment and sintered at the constant temperature of 750-800 ℃ for 10-15h in the high-purity nitrogen environment. Meanwhile, under the high-temperature environment of 10-15h, the graphene possibly reacts with the anode material with oxide property to influence the performance of the finished product.
CN110299525A discloses a preparation method of a graphene-coated lithium ion battery positive electrode material, and provides a preparation method of a graphene-coated lithium ion battery positive electrode material. The first aspect of the invention provides a preparation method of a graphene-coated lithium ion battery anode material, which comprises the steps of mixing a substance A containing graphene, an organic solvent-1 and an anode active substance to form a substance B, and then carrying out spray drying on the substance B after the substance B acts on an electromagnetic field; wherein the weight ratio of the substance A to the positive electrode activity is (0.2-1): (99.6-99). The preparation of the cathode material also needs to be carried out after spray drying, and the process is complex.
CN105762345A discloses a method for performing heat treatment by spraying a mixture of a positive electrode material, graphene and organic carbon source dispersion liquid into a vertical calciner filled with a protective gas by using a sprayer, which has the disadvantages that a large amount of protective gas needs to be added, the production cost is increased, and an organic carbon source other than graphene needs to be added, which reduces the specific capacity of the whole composite material, the heat treatment time is too short, the organic carbon source is hard to carbonize, the coating on the surface of the positive electrode material increases the internal resistance of the material, and is not favorable for the exertion of the electrochemical performance of the positive electrode material.
In conclusion, it is important to develop a preparation method for coating a positive electrode material, which is simple and easy to operate and has low cost, and the positive electrode material obtained by the method can remarkably improve the conductivity and the thermal stability of the lithium ion battery.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide a positive electrode composite material, a preparation method and application thereof, and the battery obtained by using the positive electrode composite material is remarkably improved in conductivity and thermal stability.
In order to achieve the purpose, the invention adopts the following technical scheme:
in a first aspect, the present invention provides a positive electrode composite material comprising a cobalt-free positive electrode material and a composite carbon coating layer formed on the surface thereof;
the particle size of the cobalt-free cathode material is 3-5 μm, such as 3.5 μm, 4.0 μm, 4.5 μm and the like;
the composite carbon includes graphene.
The particle size of the cobalt-free anode material is 3-5 mu m, and the cobalt-free anode material with the particle size within the range is more beneficial to coating composite carbon. The electronic conductivity of the cobalt-free anode material can be effectively improved by the graphene in the composite carbon, the electrolyte can be effectively isolated by the cobalt-free anode material coated by the composite carbon, the occurrence of side reactions is reduced, and the first charge-discharge capacity of the material is improved.
Preferably, the graphene has a sheet diameter of 1-2 μm, such as 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm, and the like.
The sheet diameter of the graphene is 1-2 mu m, and the graphene with the sheet diameter in the range can better coat the cobalt-free anode material, is not easy to agglomerate, and is beneficial to improving the ionic conductivity of the cobalt-free anode material.
Preferably, the graphene has a thickness of less than 2nm, such as 1.5nm, 1.0nm, 0.5nm, and the like.
The thickness of the graphene is less than 2nm, and the graphene in the thickness range can well coat the cobalt-free anode material and reduce the self-aggregation of the graphene.
Preferably, the composite carbon further includes conductive carbon black (SP) and/or Carbon Nanotubes (CNT).
Preferably, the mass ratio of graphene, SP and CNT in the composite carbon is (1-3): (0.3-0.6), for example 1-3 may be 1.5, 2, 2.5, etc., 0.3-0.6 may be 0.4, 0.5, etc., preferably 2:0.5: 0.5.
Preferably, the mass ratio of the cobalt-free cathode material to graphene is (0.98-1.02): (0.01-0.04), for example, 0.98-1.02 may be 0.99, 1, 1.01, etc., 0.01-0.04 may be 0.02, 0.03, etc., preferably 1: 0.02.
The mass ratio of the cobalt-free cathode material to the graphene is preferably 1:0.02, because the cobalt-free cathode material and the graphene with the mass ratio can obtain a cathode material with a good coating effect.
In a second aspect, the present invention provides a method for preparing the positive electrode composite material according to the first aspect, the method comprising the steps of: and mixing the cobalt-free anode material with the composite carbon slurry, and spray-drying to obtain the anode composite material.
The anode composite material obtained by the spray drying method does not need to be calcined, is sintering-free, greatly reduces the production cost, is simple to operate, and can be produced in a large scale.
Preferably, the composite carbon slurry includes composite carbon, a dispersant and a solvent.
Preferably, the dispersant comprises any one or a combination of at least two of polyvinylpyrrolidone (PVP), carboxymethylcellulose (CMC), polyvinylidene fluoride (PVDF), polyvinyl alcohol (PVA) or polypyrrole (PPY), with typical but non-limiting combinations including combinations of PVP and CMC, PVDF, PVA and PPY, PVP, CMC, PVDF, PVA and PPY, and the like.
Preferably, the solvent comprises N-methylpyrrolidone (NMP).
Preferably, the mass percentage of the dispersant in the composite carbon slurry is 0.3% -0.7%, such as 0.4%, 0.5%, 0.6%, etc., preferably 0.5%.
Preferably, the mass percentage of the graphene in the composite carbon slurry is 0.2% to 0.5%, such as 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, etc., preferably 0.35%.
Preferably, the preparation method of the composite carbon slurry comprises the following steps:
and uniformly mixing the dispersing agent in the solvent, adding the graphene, the SP and the carbon nano tube, and stirring and mixing.
Preferably, the cobalt-free cathode material and the composite carbon slurry are mixed by stirring;
preferably, the rotation speed of the stirring is 800-.
Preferably, the stirring time is 20-40min, such as 25min, 30min, 35min, etc., preferably 30 min.
Preferably, the temperature of the air inlet of the spray drying is 180-210 ℃, such as 190 ℃, 200 ℃, 210 ℃ and the like, preferably 199 ℃.
Preferably, theThe air speed of the spray drying is 25-35m3H, e.g. 27m3/h、29m3/h、31m3/h、33m3H, etc., preferably 31m3/h。
Preferably, the injection peristaltic pump speed of the spray drying is 300-400mL/h, such as 325mL/h, 350mL/h, 375mL/h, etc., preferably 350 mL/h.
Preferably, the spray-dried gas flow is 5-15NL/min, e.g. 8NL/min, 10NL/min, 12NL/min, 14NL/min etc., preferably 10 NL/min.
As a preferred technical scheme, the preparation method comprises the following steps:
(1) preparation of composite carbon slurry
Uniformly mixing a dispersing agent in a solvent, adding SP, a carbon nano tube and graphene with the sheet diameter of 1-2 mu m and the thickness of less than 2nm, and stirring and mixing to obtain composite carbon slurry with the mass percentages of the dispersing agent and the graphene of 0.3-0.7% and 0.2-0.5%, respectively;
(2) preparation of positive electrode composite material
Adding a cobalt-free anode material with the mass ratio of (0.98-1.02) to (0.01-0.04) of 3-5 mu m to the obtained composite carbon slurry, stirring at the rotation speed of 1200rpm/min of 800-.
In a third aspect, the invention provides a use of the positive electrode composite material of the first aspect in a lithium ion battery.
Compared with the prior art, the invention has the following beneficial effects:
the particle size of the cobalt-free anode material is 3-5 mu m, and the cobalt-free anode material with the particle size within the range is more beneficial to coating composite carbon. The graphene is selected from the composite carbon, so that the ionic conductivity of the cobalt-free anode material can be effectively improved, the electrolyte can be effectively isolated by the cobalt-free anode material coated by the composite carbon, the occurrence of side reactions is reduced, and the first charge-discharge efficiency of the material is improved. The capacity retention rate of the composite carbon-coated cobalt-free anode material at a 4C rate is improved to 78-80%.
Drawings
FIG. 1 is a graph of 1C cycle performance for example 1 and comparative example 3;
FIG. 2 is a graph comparing the rate performance of example 1 and comparative example 3;
FIG. 3 is a graph of the electrical conductivity of the powders of example 1 and comparative example 3;
FIG. 4 is a graph of the AC impedance of example 1 and comparative example 3;
FIG. 5 is a schematic view of the spray drying principle of examples 1 to 10 and comparative examples 1 to 2;
FIG. 6 is a schematic view of the principle of the positive electrode composite material of example 1;
FIG. 7 is a scanning electron micrograph of a positive electrode composite material according to example 1.
Detailed Description
For the purpose of facilitating an understanding of the present invention, the present invention will now be described by way of examples. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.
The following examples and comparative examples use the following raw materials with the following detailed information:
example 1
This example provides a positive electrode composite material including a cobalt-free positive electrode material (LiNi) in a mass ratio of 1:0.020.75Mn0.25O2Particle size of 4 μm) and graphene (sheet size of 2 μm, thickness of 1.5 nm);
the invention also provides a preparation method of the anode composite material, which comprises the following steps:
(1) preparation of graphene slurry
Uniformly mixing PVP in NMP, adding graphene (the sheet diameter is 2 mu m and the thickness is 1.5nm), stirring and mixing to obtain composite carbon slurry with PVP and graphene respectively accounting for 0.5% and 0.35% in mass percentage;
(2) preparation of positive electrode composite material
LiNi with the mass ratio of 1:0.02 to graphene of 4 mu m0.75Mn0.25O2Adding into the obtained composite carbon slurry, stirring at 1000rpm/min for 30min at 199 deg.C of air inlet and 31m of air speed3And/h, carrying out spray drying under the conditions that the speed of a sample feeding peristaltic pump is 30% and the gas flow rate is 10NL/min (the schematic diagram of the spray drying principle is shown in figure 5), and obtaining the positive electrode composite material (the schematic diagram of the positive electrode composite material principle is shown in figure 6).
Example 2
This example provides a positive electrode composite material including a cobalt-free positive electrode material (LiNi) having a mass ratio of 0.98:0.01:0.00250.75Mn0.25O2Particle size of 3 μm), graphene (sheet size of 1 μm, thickness of 1nm), and CNT;
the invention also provides a preparation method of the anode composite material, which comprises the following steps:
(1) preparation of composite carbon slurry
Uniformly mixing CMC and PVDF in NMP, adding graphene (with the sheet diameter of 1 mu m and the thickness of 1nm) and CNT, stirring and mixing to obtain composite carbon slurry with the mass percentages of CMC, PVDF and graphene being 0.2%, 0.1% and 0.2%, respectively;
(2) preparation of positive electrode composite material
LiNi with the mass ratio of 0.98:0.01 to graphene of 4 mu m0.75Mn0.25O2Adding into the obtained composite carbon slurry, stirring at 800rpm/min for 40min at air inlet temperature of 180 deg.C and air speed of 25m3And h, carrying out spray drying under the conditions that the speed of a sample injection peristaltic pump is 25% and the gas flow is 5NL/min to obtain the anode composite material.
Example 3
The present embodiment provides a positive electrode composite material, which is a positive electrode composite materialThe material comprises a cobalt-free positive electrode material (LiNi) with the mass ratio of 1.02:0.04:0.010.75Mn0.25O2Particle size of 5 μm), graphene (sheet size of 2 μm, thickness of 0.5nm), and SP;
the invention also provides a preparation method of the anode composite material, which comprises the following steps:
(1) preparation of composite carbon slurry
Uniformly mixing PPY in NMP, adding graphene (with the sheet diameter of 2 mu m and the thickness of 0.5nm) and SP, stirring and mixing to obtain composite carbon slurry with the mass percentages of PPY and graphene being 0.7% and 0.5%, respectively;
(2) preparation of positive electrode composite material
LiNi with the mass ratio of 1.02:0.04 to graphene of 4 mu m0.75Mn0.25O2Adding into the obtained composite carbon slurry, stirring at 1200rpm/min for 20min at air inlet temperature of 210 deg.C and air speed of 35m3And h, carrying out spray drying under the conditions that the speed of a sample injection peristaltic pump is 40% and the gas flow is 15NL/min to obtain the anode composite material.
Examples 4 to 7
Examples 4 to 7 differ from example 1 only in the sheet diameters of graphene, which were 0.5 μm, 1 μm, 2 μm and 3 μm in examples 4 to 7, respectively.
Example 8
The present embodiment is different from embodiment 8 only in the thickness of graphene, which is 4nm in the present embodiment.
Examples 9 to 10
Examples 9 to 10 differ from the examples only in the particle size of the cobalt-free cathode material, which was 3 μm and 5 μm in examples 9 to 10, respectively.
Comparative examples 1 to 2
Comparative examples 1-2 differ from example 1 only in the particle size of the cobalt-free cathode material, which was 2 μm and 7 μm in comparative examples 1-2, respectively.
Comparative example 3
Comparative example 3 is different from example 1 in that the cobalt-free cathode material in comparative example 3 is not subjected to composite carbon coating.
Performance testing
(1)1C cycle Performance
The button cell prepared by the positive electrode composite materials in the examples 1 to 10 and the comparative examples 1 to 2 and the cobalt-free positive electrode material in the comparative example 3 was tested by using a blue tester, the voltage range was 3V to 4.4V, 0.1C was charged and discharged for one cycle, then 0.5C constant current and constant voltage charging was carried out, the cutoff current was 0.05C, 1C was used for constant current discharging, 50 cycles were carried out, and relevant data of parameters such as the first discharge capacity, the first coulombic efficiency, the 50 th cycle discharge capacity and the 50 th cycle capacity retention rate were obtained.
The test results are shown in table 1 and fig. 1.
(2) Rate capability
Testing the button cell prepared by the positive electrode composite materials in examples 1-10 and comparative examples 1-2 and the cobalt-free positive electrode material in comparative example 3 by using a blue tester, wherein the voltage range is 3V-4.4V, constant-current and constant-voltage charging is carried out at a current of 0.5C, and the charging cut-off current is 0.05C; constant current discharge was performed at 0.1C, 0.3C, 0.5C, 1C, 2C, 4C, and 0.1C currents, respectively, with a discharge cutoff voltage of 3V.
The test results are shown in table 2 and fig. 2.
(3) Electrical conductivity of powder
The positive electrode composites in examples 1 to 10 and comparative examples 1 to 2 and the cobalt-free positive electrode material in comparative example 3 were subjected to a powder conductivity test using a mitsubishi PD-51 four-probe powder tester under a pressure of 12KN, and data values were read.
The test results are shown in fig. 3.
(4) AC impedance
The positive electrode composites of examples 1-10 and comparative examples 1-2 and coin cells made with the cobalt-free positive electrode material of comparative example 3 were tested using a french Bio-Logic VMP3 multi-channel electrochemical workstation, with a frequency range of 0.1-10KHz and a sweep rate of 0.5 mV/S.
The test results are shown in fig. 4.
(5) Morphology of the positive electrode composite material:
the positive electrode composite materials in examples 1 to 10 and comparative examples 1 to 2 and the cobalt-free positive electrode material in comparative example 3 were subjected to morphology testing by using a scanning electron microscope.
The test results are shown in fig. 7.
Fig. 1 is a graph of 1C cycle performance of example 1 and comparative example 3, showing that the capacity retention of the positive electrode composite material after 50 cycles is increased from 95.27% to 98.95% compared to the cobalt-free positive electrode material, improving the cycle stability of the cobalt-free positive electrode material.
TABLE 1
Table 1 is data on cycle performance of examples 1 to 10 and comparative examples 1 to 3, and it can be seen from the table that the capacity retention rate of the positive electrode composite material after 50 cycles is improved to 98% to 99%.
TABLE 2
Table 2 is data relating to rate performance of examples 1-10 and comparative examples 1-3, and it can be seen from the table that the capacity retention of the positive electrode composite material at 4C rate is improved to 78% -80%.
Fig. 2 is a graph comparing the rate performance of example 1 and comparative example 3, wherein each rate has two sets of bars, the left side is comparative example 3, and the right side is example 1, and the graph shows that the capacity retention rate of the positive electrode composite material is improved from 72.5% to 78.8% compared with the cobalt-free positive electrode material 4C rate, which proves that the spray drying method can effectively improve the electronic conductivity and the ionic conductivity of the positive electrode material. The data show that the capacity retention rate of the positive electrode composite material under the 4C multiplying power is 78-80%.
FIG. 3 is a graph of the powder conductivities of example 1 and comparative example 3, showing that the powder conductivities of the positive electrode composite material compared to the cobalt-free positive electrode material can be varied from 2.48X 10-3The S/cm is increased to 1.19 multiplied by 10-2S/cm, the electronic conductivity of the anode composite material is effectively improved. The data show that the powder conductivity of the positive electrode composite material is 1-3X 10-2S/cm。
Fig. 4 is a graph of ac impedance of example 1 and comparative example 3, and the ac impedance of the positive electrode composite material can be reduced from 110 Ω to 39 Ω compared to the cobalt-free positive electrode material, demonstrating that the ionic conductivity of the cobalt-free positive electrode material can also be effectively improved using the spray drying method. The data show that the ac impedance of the positive electrode composite is 20-50 Ω.
Fig. 7 is a scanning electron microscope image of the cathode composite material of example 1, which shows that graphene achieves a good coating effect on a cobalt-free cathode material.
The applicant states that the present invention is illustrated in detail by the above examples, but the present invention is not limited to the above detailed methods, i.e. it is not meant that the present invention must rely on the above detailed methods for its implementation. It should be understood by those skilled in the art that any modification of the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.
Claims (10)
1. The positive electrode composite material is characterized by comprising a cobalt-free positive electrode material and a composite carbon coating layer formed on the surface of the cobalt-free positive electrode material;
the particle size of the cobalt-free anode material is 3-5 mu m;
the composite carbon includes graphene.
2. The positive electrode composite material according to claim 1, wherein the graphene has a sheet diameter of 1 to 2 μm;
preferably, the graphene is less than 2nm thick;
preferably, the composite carbon further comprises conductive carbon black and/or carbon nanotubes.
3. The positive electrode composite material according to claim 1 or 2, wherein the mass ratio of the cobalt-free positive electrode material to the graphene is (0.98-1.02): (0.01-0.04).
4. A method for preparing a positive electrode composite material according to claims 1-3, characterized in that it comprises the steps of: and mixing the cobalt-free anode material with the composite carbon slurry, and spray-drying to obtain the anode composite material.
5. The production method according to claim 4, wherein the composite carbon slurry comprises composite carbon, a dispersant, and a solvent;
preferably, the dispersing agent comprises any one or a combination of at least two of polyvinylpyrrolidone, carboxymethyl cellulose, polyvinylidene fluoride, polyvinyl alcohol or polypyrrole;
preferably, the solvent comprises N-methylpyrrolidone;
preferably, the mass percentage of the dispersant in the composite carbon slurry is 0.3% -0.7%, preferably 0.5%;
preferably, the mass percentage of the graphene in the composite carbon slurry is 0.2% -0.5%, and preferably 0.35%.
6. The method according to claim 4 or 5, wherein the method for preparing the composite carbon slurry comprises the steps of:
and uniformly mixing the dispersing agent in the solvent, adding the graphene, the conductive carbon black and the carbon nano tube, and stirring and mixing.
7. The production method according to any one of claims 4 to 6, wherein the mixing of the cobalt-free positive electrode material and the composite carbon slurry is stirring mixing;
preferably, the rotation speed of the stirring is 800-;
preferably, the stirring time is 20-40 min.
8. The method according to any one of claims 4 to 7, wherein the temperature of the air inlet of the spray drying is 180-210 ℃, preferably 199 ℃;
preferably, the air speed of the spray drying is 25-35m3H, preferably 31m3/h；
Preferably, the speed of the injection peristaltic pump for spray drying is 300-400mL/h, preferably 350 mL/h;
preferably, the spray-dried gas flow is 5-15NL/min, preferably 10 NL/min.
9. The method according to any one of claims 4 to 8, characterized by comprising the steps of:
(1) preparation of composite carbon slurry
Uniformly mixing a dispersing agent in a solvent, adding conductive carbon black, carbon nano tubes and graphene with the sheet diameter of 1-2 mu m and the thickness of less than 2nm, and stirring and mixing to obtain composite carbon slurry with the mass percentages of the dispersing agent and the graphene of 0.3-0.7% and 0.2-0.5%, respectively;
(2) preparation of positive electrode composite material
Adding a cobalt-free anode material with the mass ratio of (0.98-1.02) to (0.01-0.04) of 3-5 mu m into the obtained composite carbon slurry, stirring at the rotating speed of 1200rpm/min for 20-40min at the air inlet temperature of 180-210 ℃ and the air speed of 25-35m3And h, carrying out spray drying under the conditions that the speed of a sample injection peristaltic pump is 25% -40% and the gas flow is 5-15NL/min to obtain the anode composite material.
10. Use of a positive electrode composite material according to any one of claims 1 to 3 in a lithium ion battery.
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| Publication number | Priority date | Publication date | Assignee | Title |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105070888A (en) * | 2015-07-09 | 2015-11-18 | 山东玉皇新能源科技有限公司 | Coupled carbon nano tube-graphene composite three-dimensional network structure-coated ternary material and preparation method thereof |
| CN105826531A (en) * | 2016-03-25 | 2016-08-03 | 河南鹏辉能源科技有限公司 | Preparation method for in-situ carbon-coated lithium nickel manganese oxide anode material and product thereof |
| CN106299321A (en) * | 2016-11-11 | 2017-01-04 | 宁波富理电池材料科技有限公司 | A kind of modified lithium-rich manganese-based anode material and preparation method thereof |
| CN106328924A (en) * | 2015-07-03 | 2017-01-11 | 北京化工大学 | Carbon-coated lithium nickel manganese oxide positive electrode material with high potential and preparation method of positive electrode material |
| CN107275606A (en) * | 2017-06-13 | 2017-10-20 | 山东大学 | A kind of carbon coating spinel lithium manganate nano composite material and preparation method and application |
| CN109473642A (en) * | 2018-10-10 | 2019-03-15 | 国联汽车动力电池研究院有限责任公司 | A kind of modified lithium nickel cobalt manganese oxide positive electrode of nano-carbon material and preparation method |
| CN110299525A (en) * | 2019-07-02 | 2019-10-01 | 宁夏汉尧石墨烯储能材料科技有限公司 | A kind of preparation method of graphene coated anode material for lithium-ion batteries |
-
2020
- 2020-09-28 CN CN202011043389.XA patent/CN112186158A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106328924A (en) * | 2015-07-03 | 2017-01-11 | 北京化工大学 | Carbon-coated lithium nickel manganese oxide positive electrode material with high potential and preparation method of positive electrode material |
| CN105070888A (en) * | 2015-07-09 | 2015-11-18 | 山东玉皇新能源科技有限公司 | Coupled carbon nano tube-graphene composite three-dimensional network structure-coated ternary material and preparation method thereof |
| CN105826531A (en) * | 2016-03-25 | 2016-08-03 | 河南鹏辉能源科技有限公司 | Preparation method for in-situ carbon-coated lithium nickel manganese oxide anode material and product thereof |
| CN106299321A (en) * | 2016-11-11 | 2017-01-04 | 宁波富理电池材料科技有限公司 | A kind of modified lithium-rich manganese-based anode material and preparation method thereof |
| CN107275606A (en) * | 2017-06-13 | 2017-10-20 | 山东大学 | A kind of carbon coating spinel lithium manganate nano composite material and preparation method and application |
| CN109473642A (en) * | 2018-10-10 | 2019-03-15 | 国联汽车动力电池研究院有限责任公司 | A kind of modified lithium nickel cobalt manganese oxide positive electrode of nano-carbon material and preparation method |
| CN110299525A (en) * | 2019-07-02 | 2019-10-01 | 宁夏汉尧石墨烯储能材料科技有限公司 | A kind of preparation method of graphene coated anode material for lithium-ion batteries |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2023193826A1 (en) | 2022-06-30 | 2023-10-12 | 北京当升材料科技股份有限公司 | Positive electrode material, preparation method therefor, and application thereof |
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