CN116053401A - Composite positive electrode plate, preparation method thereof and lithium battery - Google Patents
Composite positive electrode plate, preparation method thereof and lithium battery Download PDFInfo
- Publication number
- CN116053401A CN116053401A CN202211724123.0A CN202211724123A CN116053401A CN 116053401 A CN116053401 A CN 116053401A CN 202211724123 A CN202211724123 A CN 202211724123A CN 116053401 A CN116053401 A CN 116053401A
- Authority
- CN
- China
- Prior art keywords
- positive electrode
- composite
- slurry
- solid electrolyte
- electrolyte
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000002131 composite material Substances 0.000 title claims abstract description 195
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 18
- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 18
- 238000002360 preparation method Methods 0.000 title claims abstract description 11
- 239000002002 slurry Substances 0.000 claims abstract description 115
- 239000007784 solid electrolyte Substances 0.000 claims abstract description 111
- 239000003792 electrolyte Substances 0.000 claims abstract description 63
- 239000000203 mixture Substances 0.000 claims abstract description 25
- 239000000463 material Substances 0.000 claims description 75
- 239000002904 solvent Substances 0.000 claims description 43
- 238000001035 drying Methods 0.000 claims description 37
- 239000011230 binding agent Substances 0.000 claims description 36
- 238000000498 ball milling Methods 0.000 claims description 30
- 238000004519 manufacturing process Methods 0.000 claims description 19
- 238000000227 grinding Methods 0.000 claims description 17
- 238000002156 mixing Methods 0.000 claims description 16
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 15
- 239000011248 coating agent Substances 0.000 claims description 15
- 238000000576 coating method Methods 0.000 claims description 15
- 239000007774 positive electrode material Substances 0.000 claims description 15
- 239000006258 conductive agent Substances 0.000 claims description 14
- 239000004576 sand Substances 0.000 claims description 14
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 claims description 12
- 229910003002 lithium salt Inorganic materials 0.000 claims description 12
- 159000000002 lithium salts Chemical class 0.000 claims description 12
- 238000005245 sintering Methods 0.000 claims description 12
- 238000001354 calcination Methods 0.000 claims description 11
- 239000002245 particle Substances 0.000 claims description 11
- 239000002994 raw material Substances 0.000 claims description 11
- 239000000843 powder Substances 0.000 claims description 10
- 238000005303 weighing Methods 0.000 claims description 6
- 238000003801 milling Methods 0.000 claims description 4
- 239000003960 organic solvent Substances 0.000 claims description 4
- 229910052721 tungsten Inorganic materials 0.000 claims description 4
- 229910052725 zinc Inorganic materials 0.000 claims description 4
- 239000002227 LISICON Substances 0.000 claims description 3
- 239000005279 LLTO - Lithium Lanthanum Titanium Oxide Substances 0.000 claims description 3
- 239000002228 NASICON Substances 0.000 claims description 3
- 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 claims description 3
- QHGJSLXSVXVKHZ-UHFFFAOYSA-N dilithium;dioxido(dioxo)manganese Chemical compound [Li+].[Li+].[O-][Mn]([O-])(=O)=O QHGJSLXSVXVKHZ-UHFFFAOYSA-N 0.000 claims description 3
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 claims description 3
- 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 description 3
- 239000000126 substance Substances 0.000 claims description 3
- 238000000034 method Methods 0.000 abstract description 24
- 239000011267 electrode slurry Substances 0.000 abstract description 18
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 18
- 230000000052 comparative effect Effects 0.000 description 13
- MRELNEQAGSRDBK-UHFFFAOYSA-N lanthanum(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[La+3].[La+3] MRELNEQAGSRDBK-UHFFFAOYSA-N 0.000 description 10
- 230000008569 process Effects 0.000 description 10
- 238000012360 testing method Methods 0.000 description 10
- 229910052782 aluminium Inorganic materials 0.000 description 8
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 8
- 229910052593 corundum Inorganic materials 0.000 description 8
- 239000010431 corundum Substances 0.000 description 8
- 239000011888 foil Substances 0.000 description 8
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 description 8
- 229910052808 lithium carbonate Inorganic materials 0.000 description 8
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 description 8
- 229910001928 zirconium oxide Inorganic materials 0.000 description 8
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 7
- 229910001416 lithium ion Inorganic materials 0.000 description 7
- 238000011056 performance test Methods 0.000 description 6
- 239000002033 PVDF binder Substances 0.000 description 5
- 150000001875 compounds Chemical class 0.000 description 5
- 229920005569 poly(vinylidene fluoride-co-hexafluoropropylene) Polymers 0.000 description 5
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 5
- 150000003839 salts Chemical class 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- KWGKDLIKAYFUFQ-UHFFFAOYSA-M lithium chloride Chemical compound [Li+].[Cl-] KWGKDLIKAYFUFQ-UHFFFAOYSA-M 0.000 description 4
- IIPYXGDZVMZOAP-UHFFFAOYSA-N lithium nitrate Chemical compound [Li+].[O-][N+]([O-])=O IIPYXGDZVMZOAP-UHFFFAOYSA-N 0.000 description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 230000004048 modification Effects 0.000 description 4
- 238000012986 modification Methods 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 description 3
- 238000005520 cutting process Methods 0.000 description 3
- 239000002270 dispersing agent Substances 0.000 description 3
- 238000005265 energy consumption Methods 0.000 description 3
- 238000000265 homogenisation Methods 0.000 description 3
- 230000037427 ion transport Effects 0.000 description 3
- 229910003473 lithium bis(trifluoromethanesulfonyl)imide Inorganic materials 0.000 description 3
- QSZMZKBZAYQGRS-UHFFFAOYSA-N lithium;bis(trifluoromethylsulfonyl)azanide Chemical compound [Li+].FC(F)(F)S(=O)(=O)[N-]S(=O)(=O)C(F)(F)F QSZMZKBZAYQGRS-UHFFFAOYSA-N 0.000 description 3
- 238000005096 rolling process Methods 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- 229920003171 Poly (ethylene oxide) Polymers 0.000 description 2
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 2
- YRKCREAYFQTBPV-UHFFFAOYSA-N acetylacetone Chemical compound CC(=O)CC(C)=O YRKCREAYFQTBPV-UHFFFAOYSA-N 0.000 description 2
- 238000007792 addition Methods 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 238000005054 agglomeration Methods 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 239000001569 carbon dioxide Substances 0.000 description 2
- PQVSTLUFSYVLTO-UHFFFAOYSA-N ethyl n-ethoxycarbonylcarbamate Chemical compound CCOC(=O)NC(=O)OCC PQVSTLUFSYVLTO-UHFFFAOYSA-N 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 150000004679 hydroxides Chemical class 0.000 description 2
- 229910052746 lanthanum Inorganic materials 0.000 description 2
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 2
- XIXADJRWDQXREU-UHFFFAOYSA-M lithium acetate Chemical compound [Li+].CC([O-])=O XIXADJRWDQXREU-UHFFFAOYSA-M 0.000 description 2
- GLXDVVHUTZTUQK-UHFFFAOYSA-M lithium hydroxide monohydrate Substances [Li+].O.[OH-] GLXDVVHUTZTUQK-UHFFFAOYSA-M 0.000 description 2
- 229940040692 lithium hydroxide monohydrate Drugs 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 239000010955 niobium Substances 0.000 description 2
- -1 oxides Chemical class 0.000 description 2
- BPUBBGLMJRNUCC-UHFFFAOYSA-N oxygen(2-);tantalum(5+) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Ta+5].[Ta+5] BPUBBGLMJRNUCC-UHFFFAOYSA-N 0.000 description 2
- 229920002037 poly(vinyl butyral) polymer Polymers 0.000 description 2
- 229920002451 polyvinyl alcohol Polymers 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- PBCFLUZVCVVTBY-UHFFFAOYSA-N tantalum pentoxide Inorganic materials O=[Ta](=O)O[Ta](=O)=O PBCFLUZVCVVTBY-UHFFFAOYSA-N 0.000 description 2
- 238000010998 test method Methods 0.000 description 2
- 229910052726 zirconium Inorganic materials 0.000 description 2
- QTBSBXVTEAMEQO-UHFFFAOYSA-M Acetate Chemical compound CC([O-])=O QTBSBXVTEAMEQO-UHFFFAOYSA-M 0.000 description 1
- 229920000049 Carbon (fiber) Polymers 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- 229940126062 Compound A Drugs 0.000 description 1
- NLDMNSXOCDLTTB-UHFFFAOYSA-N Heterophylliin A Natural products O1C2COC(=O)C3=CC(O)=C(O)C(O)=C3C3=C(O)C(O)=C(O)C=C3C(=O)OC2C(OC(=O)C=2C=C(O)C(O)=C(O)C=2)C(O)C1OC(=O)C1=CC(O)=C(O)C(O)=C1 NLDMNSXOCDLTTB-UHFFFAOYSA-N 0.000 description 1
- 229910013188 LiBOB Inorganic materials 0.000 description 1
- 229910013870 LiPF 6 Inorganic materials 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- NRJJZXGPUXHHTC-UHFFFAOYSA-N [Li+].[O--].[O--].[O--].[O--].[Zr+4].[La+3] Chemical compound [Li+].[O--].[O--].[O--].[O--].[Zr+4].[La+3] NRJJZXGPUXHHTC-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 239000004917 carbon fiber Substances 0.000 description 1
- 229910021393 carbon nanotube Inorganic materials 0.000 description 1
- 239000002041 carbon nanotube Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000001351 cycling effect Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- XYIBRDXRRQCHLP-UHFFFAOYSA-N ethyl acetoacetate Chemical compound CCOC(=O)CC(C)=O XYIBRDXRRQCHLP-UHFFFAOYSA-N 0.000 description 1
- 229910021389 graphene Inorganic materials 0.000 description 1
- 150000004820 halides Chemical class 0.000 description 1
- 229910003480 inorganic solid Inorganic materials 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000002715 modification method Methods 0.000 description 1
- ZKATWMILCYLAPD-UHFFFAOYSA-N niobium pentoxide Inorganic materials O=[Nb](=O)O[Nb](=O)=O ZKATWMILCYLAPD-UHFFFAOYSA-N 0.000 description 1
- URLJKFSTXLNXLG-UHFFFAOYSA-N niobium(5+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Nb+5].[Nb+5] URLJKFSTXLNXLG-UHFFFAOYSA-N 0.000 description 1
- 229920002401 polyacrylamide Polymers 0.000 description 1
- 229910001251 solid state electrolyte alloy Inorganic materials 0.000 description 1
Images
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
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
-
- 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
-
- 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
- H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
- H01M10/0561—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of inorganic materials only
- H01M10/0562—Solid materials
-
- 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
- H01M10/36—Accumulators not provided for in groups H01M10/05-H01M10/34
- H01M10/38—Construction or manufacture
-
- 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
- H01M4/04—Processes of manufacture in general
- H01M4/0402—Methods of deposition of the material
- H01M4/0404—Methods of deposition of the material by coating on electrode collectors
-
- 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
- H01M4/04—Processes of manufacture in general
- H01M4/0402—Methods of deposition of the material
- H01M4/0407—Methods of deposition of the material by coating on an electrolyte layer
-
- 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
- H01M4/04—Processes of manufacture in general
- H01M4/0471—Processes of manufacture in general involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
- H01M4/139—Processes of manufacture
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/028—Positive electrodes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Inorganic Chemistry (AREA)
- Secondary Cells (AREA)
Abstract
The invention relates to a composite positive plate, a preparation method thereof and a lithium battery. The composite positive electrode plate comprises a positive electrode composite material layer and a composite electrolyte layer which are sequentially formed on the surface of a positive electrode current collector, wherein a mixture layer of the positive electrode composite material and the composite electrolyte is formed at the interface of the positive electrode composite material layer and the composite electrolyte layer. In the method for preparing the composite positive electrode plate, the positive electrode composite slurry is not completely dried, and then the solid electrolyte slurry is coated, so that the solid electrolyte slurry and the positive electrode slurry are compounded, and the interface impedance between the solid electrolyte slurry and the positive electrode slurry is reduced.
Description
Technical Field
The invention belongs to the field of battery material preparation, and particularly relates to a composite positive electrode plate, a preparation method thereof and a lithium battery.
Background
Solid-state electrolytes are known for their high safety, and have advantages such as excellent thermal and electrochemical stability, wide electrochemical window, and excellent mechanical properties, and are well known to academia and industry. Currently, nano solid electrolyte materials have been applied in preparing solid electrolyte layers, especially inorganic solid electrolyte thin layers and organic-inorganic composite solid electrolytes. In addition, the nano solid electrolyte material is also applied to the processes of surface modification of the traditional diaphragm, surface coating of the electrode material and the like. The garnet-type oxide solid-state electrolyte lithium lanthanum zirconium oxide has the advantages of higher ion conductivity, good stability to lithium and the like.
The oxide solid electrolyte is prepared into a ceramic sheet or a composite film, and the contact between the pole piece and the solid electrolyte is ensured by pressurizing the pole piece or adding a binder, so that the interface impedance is reduced, but the process is very complex, and the large-scale application is difficult to realize.
Disclosure of Invention
In view of the above technical problems, an object of the present invention is to provide a positive electrode sheet capable of reducing the resistance of a solid electrolyte and a positive electrode slurry, and a method for producing the positive electrode sheet at low cost with a simple method.
Solution for solving the problem
According to the invention, the solid electrolyte nano slurry and the positive electrode slurry are directly compounded to prepare the composite positive electrode plate, so that the interface impedance between the solid electrolyte nano slurry and the positive electrode slurry is reduced, the drying energy consumption is reduced, and the production cost is reduced.
The invention provides a composite positive electrode plate, which comprises a positive electrode composite material layer and a composite electrolyte layer which are sequentially formed on the surface of a positive electrode current collector,
wherein a mixture layer of the positive electrode composite material and the composite electrolyte is formed at the interface of the positive electrode composite material layer and the composite electrolyte layer.
The composite positive electrode sheet according to the above, wherein the positive electrode composite material layer comprises a positive electrode material, a conductive agent and a first binder; the composite electrolyte layer includes a solid electrolyte, a second binder, and a lithium salt; wherein the first binder and the second binder are the same or different.
The composite positive electrode sheet according to the above, wherein the positive electrode material is selected from one or more of lithium cobaltate, lithium iron phosphate, lithium iron manganese phosphate, lithium nickel cobalt manganate and lithium manganate; the solid electrolyte is selected from one or more of an oxide solid electrolyte, a NASICON type solid electrolyte, and a LISICON type solid electrolyte.
The composite positive electrode sheet according to the above, wherein the oxide solid electrolyte is selected from at least one of garnet-type oxide solid electrolyte and perovskite-type oxide solid electrolyte.
The composite positive electrode sheet according to above, wherein the garnet-type oxide solid electrolyte has a chemical composition of Li 7-3x A x La 3 Zr 2-y B y O 12 Wherein the doping element A is Ga and/or Al, the doping element B is one or more of Zn, ta, nb, W, mg, ca, sr, si, x is more than or equal to 0 and less than or equal to 1.0, and y is more than or equal to 0 and less than or equal to 1.0;
the perovskite oxide solid electrolyte is LLTO.
The invention also provides a preparation method of the composite positive plate, which comprises the following steps:
step S1: coating the positive electrode composite slurry on a positive electrode current collector, and drying the positive electrode composite slurry;
step S2: and before the positive electrode composite slurry is completely dried, coating the composite electrolyte slurry on the incompletely dried positive electrode composite slurry, and drying to form a mixture layer of the positive electrode composite material and the composite electrolyte at the interface of the positive electrode composite material layer and the composite electrolyte layer, thereby obtaining the composite positive electrode sheet.
The production method according to the above, wherein the thickness of the positive electrode composite slurry coated on the positive electrode current collector is 10 μm or more and 500 μm or less;
preferably, the thickness of the composite electrolyte slurry is 8 μm or more and 100 μm or less coated on the incompletely dried positive electrode composite slurry;
preferably, the thickness of the composite electrolyte slurry is smaller than the thickness of the positive electrode composite slurry;
preferably, the step S1 includes: coating the positive electrode composite slurry on a positive electrode current collector, and drying until the solvent content in the positive electrode composite slurry is 1-20% by mass, so as to obtain a positive electrode plate; or,
in the step S1, the drying temperature is 30-50 ℃ and the drying time is 0.5-12 h.
In the invention, the temperature of the drying in the step S2 is between room temperature and 100 ℃ and the time is between 1 and 12 hours.
The production method according to the above, wherein the positive electrode composite slurry is obtained by mixing and homogenizing a positive electrode material, a conductive agent, a first binder, and a first solvent;
preferably, the composite electrolyte slurry is obtained by mixing a solid electrolyte slurry obtained by mixing a sintered material of a solid electrolyte with a second solvent, followed by ball milling and sand milling, a second binder, and a lithium salt;
preferably, the mass ratio of the sintering material of the solid electrolyte to the second solvent is 1:3-1:20.
preferably, the solid electrolyte in the solid electrolyte slurry has a particle diameter D90 of 200nm to 1 μm.
The production method according to the above, wherein the first solvent and the second solvent are both selected from organic solvents, and the first solvent and the second solvent are mutually soluble;
preferably, the first solvent and the second solvent are selected from N, N-dimethylformamide and/or N-methylpyrrolidone.
The preparation method according to the above, wherein the sintered material of the solid electrolyte is obtained by the steps of:
weighing raw material powder according to a stoichiometric ratio, ball-milling and mixing, and calcining to obtain a calcined material;
crushing and ball milling the calcined material to obtain a ball grinding material;
and sintering the ball milling material to obtain a sintered material.
The invention further provides a lithium battery comprising the composite positive electrode sheet according to the above or a composite positive electrode sheet obtained by the preparation method according to the above.
ADVANTAGEOUS EFFECTS OF INVENTION
The beneficial effects of the invention are as follows:
(1) The composite positive electrode plate provided by the invention has no clear interface between the positive electrode composite material layer and the composite electrolyte layer, so that the interface impedance between the positive electrode composite material layer and the composite electrolyte layer is reduced, and the solid electrolyte is not easy to fall off from the positive electrode plate.
(2) According to the invention, the nano solid electrolyte slurry is directly utilized instead of the powder thereof, so that the problems of agglomeration of the powder, difficult storage, increased impedance caused by the formation of lithium carbonate with carbon dioxide in air, increased gas yield in a battery and influence on battery performance caused by the drying of the nano slurry are avoided.
(3) According to the invention, the positive electrode composite slurry is not completely dried, namely, before the positive electrode composite slurry is completely dried, the composite electrolyte slurry is coated on the incompletely dried positive electrode composite slurry, so that the solid electrolyte slurry and the positive electrode slurry are compounded, the interface impedance between the solid electrolyte slurry and the positive electrode slurry is reduced, and the performance of the battery cell is improved.
(4) The nano solid electrolyte slurry does not need to be dried in the use process, reduces energy consumption, reduces production cost and ensures the dispersibility of particles.
(5) When the battery is prepared, the battery can be directly prepared by compounding the battery with the negative electrode without adding a diaphragm and an electrolyte layer.
Drawings
FIG. 1 is a graph showing the results of the magnification experiments of examples 1 and 2 and comparative example 1 according to the present invention.
FIG. 2 is a graph showing the results of the cyclic experiments of examples 1 and 2 and comparative example 1 according to the present invention.
Fig. 3 shows the impedance value test results of examples 1 and 2 of the present invention and comparative example 1.
Detailed Description
The following describes embodiments of the present invention, but the present invention is not limited thereto. The present invention is not limited to the configurations described below, and various modifications are possible within the scope of the invention as claimed, and embodiments obtained by appropriately combining the technical means disclosed in the different embodiments and the appropriate combination examples are also included in the technical scope of the present invention. All documents described in the present specification are incorporated by reference in the present specification.
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 invention belongs.
In the present specification, the numerical range indicated by the term "numerical value a to numerical value B" means a range including the end point numerical value A, B.
In the present specification, unless specifically stated otherwise, "a plurality" of "a plurality of" etc. means a numerical value of 2 or more.
In this specification, the terms "substantially", "substantially" or "substantially" mean that the error is less than 5%, or less than 3%, or less than 1% as compared to the relevant perfect or theoretical standard.
In the present specification, "%" means mass% unless otherwise specified.
In the present specification, if "room temperature", "normal temperature" or the like occurs, the temperature thereof may be generally 10 to 37℃or 15 to 35 ℃.
In the present specification, the meaning of "can" or "can" includes both the meaning of the presence or absence of both, and the meaning of both the treatment and the absence of both.
In this specification, "optional" and "optionally" mean that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.
The term "comprising" in the description of the invention and the claims and in the above figures and any variants thereof is intended to cover a non-exclusive inclusion. For example, a process, method, or system, article, or apparatus that comprises a list of steps or elements is not limited to only those listed but may optionally include additional steps or elements not listed or inherent to such process, method, article, or apparatus.
Reference throughout this specification to "some/preferred embodiments," "an embodiment," etc., means that a particular element (e.g., feature, structure, property, and/or characteristic) described in connection with the embodiment is included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it is to be understood that the elements may be combined in any suitable manner in the various embodiments.
< first aspect >
A first aspect of the invention relates to a composite positive electrode sheet. The composite positive electrode plate comprises a positive electrode composite material layer and a composite electrolyte layer which are sequentially formed on the surface of a positive electrode current collector, wherein a mixture layer of the positive electrode composite material and the composite electrolyte is formed at the interface of the positive electrode composite material layer and the composite electrolyte layer.
In the invention, the positive electrode composite material layer comprises a positive electrode material, a conductive agent and a first binder.
Among them, the positive electrode material, the conductive agent and the first binder are not particularly limited, and those commonly used in the art may be used. For example, the positive electrode material may be selected from one or more of lithium cobaltate, lithium iron phosphate, lithium manganese iron phosphate, lithium nickel cobalt manganate, and lithium manganate. The conductive agent can be one or more selected from conductive carbon black, super conductive carbon black, carbon nanotube, graphene, carbon fiber and conductive graphite. The first binder may be selected from one or more of PEO, PVDF, PVDF-HFP, PVA, PVB, etc.
In the present invention, the composite electrolyte layer includes a solid electrolyte, a second binder, and a lithium salt.
Wherein the solid electrolyte is selected from one or more of oxide solid electrolyte, NASICON type solid electrolyte and LISICON type solid electrolyte. Among them, an oxide solid electrolyte is preferable.
The oxide solid electrolyte may be selected from at least one of garnet-type oxide solid electrolyte and perovskite-type oxide solid electrolyte. Wherein the saidThe garnet-type oxide solid electrolyte has the chemical composition of Li 7-3x A x La 3 Zr 2- y B y O 12 Wherein the doping element A is Ga and/or Al, the doping element B is one or more of Zn, ta, nb, W, mg, ca, sr, si, x is more than or equal to 0 and less than or equal to 1.0, and y is more than or equal to 0 and less than or equal to 1.0. The perovskite oxide solid electrolyte is LLTO.
The second binder for the composite electrolyte layer is not particularly limited either, and binders commonly used in the art can be used. For example, the second binder may be selected from one or more of PEO, PVDF, PVDF-HFP, PVA, PVB, etc., and the second binder may be the same as or different from the first binder used in the positive electrode composite material layer.
In the present invention, the lithium salt used for the composite electrolyte layer is not particularly limited, and an electrolyte lithium salt commonly used in the art can be used. For example, the lithium salt may be selected from LiPF 6 LiBOB, liTFSI, liFSI, etc.
The positive electrode current collector in the composite positive electrode sheet of the present invention is not particularly limited, and those commonly used in the art may be used. For example, the positive electrode current collector may be aluminum foil or the like.
In the existing positive electrode plate composite layer structure, a clear interface exists between the positive electrode layer and the solid electrolyte layer, so that interface impedance is relatively large. In the composite electrode of the present invention, the mixed layer (mixture of the solid electrolyte and the positive electrode material) is formed at the interface between the positive electrode layer and the solid electrolyte layer, and there is no clear interface, so that the interface resistance can be reduced, and the solid electrolyte is not easily detached from the positive electrode surface.
< second aspect >
A second aspect of the present invention relates to the method for producing a composite positive electrode sheet of the above < first aspect >. The preparation method of the composite positive plate comprises the following steps:
step S1: coating the positive electrode composite slurry on a positive electrode current collector, and drying the positive electrode composite slurry;
step S2: and before the positive electrode composite slurry is completely dried, coating the composite electrolyte slurry on the incompletely dried positive electrode composite slurry, and drying to form a mixture layer of the positive electrode composite material and the composite electrolyte at the interface of the positive electrode composite material layer and the composite electrolyte layer, thereby obtaining the composite positive electrode sheet.
Step S1
In the present invention, the positive electrode composite slurry is obtained by mixing and homogenizing a positive electrode material, a conductive agent, a first binder, and a first solvent.
The positive electrode current collector, the positive electrode material, the conductive agent, the first binder, and the second binder, the solid electrolyte, and the lithium salt described later are the same as those described in the above < first aspect >, and are not described here again.
In the present invention, the first solvent for the positive electrode composite paste is selected from an organic solvent, which may be selected from N, N-dimethylformamide and/or N-methylpyrrolidone.
The mass ratio of the positive electrode material, the conductive agent, and the first binder is not particularly limited, and any amount commonly used in the art may be used. For example, the mass ratio of the positive electrode material to the conductive agent to the first binder may be (94 to 96): 1.5 to 3.5. The amount of the first solvent used for the positive electrode composite paste is not particularly limited and may be adjusted according to actual needs.
After the positive electrode composite slurry is obtained, the positive electrode composite slurry is uniformly coated on a positive electrode current collector such as aluminum foil to a certain thickness, and then dried for a period of time at a certain temperature, so that the positive electrode composite slurry is not completely dried, namely the positive electrode composite slurry is not completely dried, and then the composite electrolyte slurry is coated on the incompletely dried positive electrode composite slurry, and the composite positive electrode sheet is obtained after complete drying.
Preferably, the step S1 includes: and coating the positive electrode composite slurry on a positive electrode current collector, and drying until the solvent content in the positive electrode composite slurry is 1-20% by mass, preferably 1-15% by mass, so as to obtain a positive electrode plate.
The drying temperature and drying time are not particularly limited as long as the positive electrode composite slurry is not completely dried, that is, the positive electrode composite slurry is not completely dried, but the solvent content is preferably 1 to 20% by mass, and more preferably 1 to 15% by mass. For example, the drying temperature in step S1 may be 30-50deg.C and the drying time may be 0.5-12 h.
In the present invention, "not completely dried" refers to a state in which the solvent in the positive electrode composite slurry is not completely volatilized.
In an embodiment of the present invention, the thickness of the positive electrode composite paste uniformly coated on the positive electrode current collector may be 10 μm or more and 500 μm or less. If the thickness is too thin, the solid electrolyte paste is easily applied, and if the thickness is too thick, the rate performance is affected.
Step S2
In the present invention, the composite electrolyte slurry is obtained by mixing and uniformly dispersing the solid electrolyte slurry, the second binder and the lithium salt. The amount ratio of the solid electrolyte slurry, the second binder and the lithium salt is not particularly limited, and may be appropriately adjusted within a range of the conventional amount in the art according to actual needs.
The above solid electrolyte slurry is obtained by mixing a sintered material of a solid electrolyte with a second solvent, followed by ball milling and sand milling.
In some specific embodiments of the invention, the sintered material of the solid electrolyte is crushed by a crusher, and is added into a ball milling tank together with a certain proportion of a second solvent and zirconia balls for ball milling, so as to obtain ball milling slurry; and then, introducing the ball milling slurry into a nano sand mill for sand milling under certain conditions, thereby obtaining the solid electrolyte slurry.
The mass ratio of the sintering material of the solid electrolyte to the second solvent may be 1:3-1:20, preferably 1:5-1:15, and more preferably 1:8-1:12, and if the ratio of the second solvent is too high, the grinding efficiency may be reduced, and if the ratio of the second solvent is too low, the uniformity of the ground particle size may be deteriorated. In the present invention, the second solvent is selected from organic solvents, which may be selected from N, N-dimethylformamide, N-methylpyrrolidone, etc. The second solvent may be the same as or different from the first solvent described above, but both of them need to be mutually soluble so that the solid electrolyte and the positive electrode slurry are closely combined after drying.
In the present invention, the solid electrolyte in the solid electrolyte slurry has a particle diameter D90 of 200nm to 1. Mu.m. Because the electrolyte slurry is ultimately used to form a solid electrolyte membrane, if the solid electrolyte particle size in the slurry is too large, it cannot be coated into a film, and a smaller electrolyte particle size is advantageous for a tighter alignment between electrolyte particles in the final electrolyte membrane and electrolyte particles, and for facilitating lithium ion transport.
In the ball milling of the above example of the present invention, the ball-to-material ratio may be 1:1 to 5:1, the rotational speed may be 200 to 1000rpm, and the ball milling time may be 2 to 12 hours.
To obtain finer nanoscale solid electrolytes, the ball-milled slurry was further sanded after ball milling. In a specific embodiment, the rotational speed of the sanding process is 1500-2500rpm and the time of the sanding process is 2-6 hours. In some preferred embodiments of the present invention, a dispersant may be added during the sanding process. The dispersing agent can be one or more selected from ethyl acetate, acetylacetone, ethyl acetoacetate and polyacrylamide. Wherein the mass ratio of the dispersing agent to the ball milling slurry is 0.01-0.1:1.
In the invention, the sintered material of the solid electrolyte is obtained by the following steps: weighing raw material powder according to a stoichiometric ratio, ball-milling and mixing, and calcining to obtain a calcined material; crushing and ball milling the calcined material to obtain a ball grinding material; and sintering the ball milling material to obtain a sintered material.
In some specific embodiments, adding a mixed material of raw material powder into a crucible, and placing the crucible into a muffle furnace to calcine at a certain temperature to obtain a calcined material; crushing the calcined material by using a crusher, and adding the crushed material into a ball milling tank again for ball milling to obtain ball grinding materials; and adding the ball milling material into the crucible again, and putting the crucible into a muffle furnace to sinter at a certain temperature, thereby obtaining the sintering material of the solid electrolyte.
The following are doped or undoped Li 7 La 3 Zr 2 O 12 The (LLZO) oxide solid electrolyte exemplifies the obtainment of a mixed material.
When the solid electrolyte is doped or undoped Li 7 La 3 Zr 2 O 12 In the case of the (LLZO) oxide solid electrolyte, the raw material powder includes a lithium source, a lanthanum source, a zirconium source, and optional additives.
Optionally, as the compound A, salts, oxides, hydroxides, etc. thereof can be used. Wherein the salt may include carbonate, nitrate, acetate, halide, and the like. For the Li compound, a lithium salt or lithium hydroxide monohydrate may be used. From the viewpoints of easiness in obtaining raw materials and cost, salts thereof, such as lithium carbonate, lithium nitrate, lithium acetate, lithium chloride, and the like, are preferably used. For the La compound and Zr compound, from the viewpoint of production cost, it is preferable to use oxides thereof, namely lanthanum oxide, zirconium oxide.
The lithium source may be lithium carbonate or lithium hydroxide monohydrate. From the viewpoints of easiness in obtaining raw materials and cost, salts thereof, such as lithium carbonate, lithium nitrate, lithium acetate, lithium chloride, and the like, are preferably used. For the lanthanum source and the zirconium source, from the viewpoint of production cost, oxides thereof, namely lanthanum oxide, zirconium oxide, are preferably used. When included, the additives may be selected from compounds comprising one or more of the elements Zn, al, ta, nb, W, mg, ga, ca, sr, si, salts, oxides, hydroxides, and the like thereof may be used. Among them, compounds of Ta are preferable.
And adding the raw material powder weighed according to the stoichiometric ratio and zirconia balls in a certain proportion into a ball milling tank, and uniformly mixing to obtain a mixed material. The ratio of zirconia balls to materials, i.e., ball to material ratio, may be 0.5:1 to 5:1.
In some embodiments of the invention, the calcination temperature of the mix may be 700-1000 ℃, and the calcination time at this temperature may be 3-12 hours; the sintering temperature of the ball abrasive may be 900-1200 ℃, and the sintering time at this temperature may be 3-12 hours.
In the present invention, the thickness of the composite electrolyte slurry is 8 μm or more and 100 μm or less, which is coated on the incompletely dried positive electrode composite slurry. Since the solid electrolyte is in the state of a paste, there is a risk of short circuit if the coating is too thin, and if it is too thick, the impedance of the electrolyte itself increases (lithium ion transport path is far).
In some preferred embodiments of the present invention, the thickness of the composite electrolyte slurry may be less than the thickness of the positive electrode composite slurry, which is more advantageous for lithium ion transport and has a lower impedance.
In step S2, the drying temperature and the drying time are not particularly limited, as long as the composite electrolyte slurry is completely dried. For example, the drying temperature may be room temperature to 100 ℃, preferably room temperature to 60 ℃, and the drying time may be 1 to 12 hours, preferably 1 to 3 hours.
In the method for preparing the composite positive electrode plate, the positive electrode composite slurry is not completely dried but is not completely dried, and then the solid electrolyte slurry is coated, so that the solid electrolyte slurry and the positive electrode slurry are mixed at the interface due to mutual dissolution of the first solvent and the second solvent, and no clear interface exists between the positive electrode composite material layer and the composite electrolyte layer, thereby reducing interface impedance between the positive electrode composite material layer and the composite electrolyte layer and improving the performance of the battery core.
In addition, the solid electrolyte slurry is used instead of the powder thereof, so that the problems of agglomeration of the powder, difficult storage, increased impedance caused by the formation of lithium carbonate with carbon dioxide in the air, increased gas yield in a battery and influence on the battery performance caused by the drying of the nano slurry can be avoided. In addition, the nano solid electrolyte slurry does not need to be dried in the use process, so that the energy consumption is reduced, the production cost is reduced, and the dispersibility of particles is ensured.
< third aspect >
The invention also provides a lithium battery, which comprises the composite positive electrode plate or the composite positive electrode plate obtained by the preparation method.
In some embodiments, after the composite positive electrode sheet is prepared, the double rollers of the roller press are heated, the composite electrode sheet is rolled, and then the sheet is cut. And (5) putting the cut pole piece into a vacuum oven for drying, and then, using the pole piece for assembling a battery and testing the performance of the pole piece.
The positive electrode composite pole piece is suitable for all-solid, semi-solid or liquid batteries. In addition, in the lithium battery comprising the positive electrode composite pole piece, electrolyte and a diaphragm are not required to be added.
Examples
The present invention will be described in detail by examples. The examples of embodiments are intended to illustrate the invention and are not to be construed as limiting the invention. The specific techniques or conditions are not identified in the examples and are performed according to techniques or conditions described in the literature in this field or according to the product specifications. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.
Example 1
According to Li 6.5 La 3 Zr 1.5 Ta 0.5 O 12 Weighing 150g of lithium carbonate (the lithium source is excessive by 20wt%), lanthanum oxide, zirconium oxide and tantalum pentoxide as mixed raw materials, putting 150g of zirconium oxide balls (with the diameter of 3mm:5mm:8 mm=1:1:1) into a ball milling tank, uniformly mixing to obtain a mixed material, putting the mixed material into a corundum crucible, and calcining in a muffle furnace at the calcining temperature of 900 ℃ for 6 hours to obtain a calcined material;
100g of the calcined material is crushed by a crusher, and then 300g of the calcined material and zirconia balls (with the diameter of 1mm:3mm:5 mm=1:1:1) are put into a ball milling tank for grinding, the grinding material is put into a corundum crucible, and the corundum crucible is sintered in a muffle furnace at the sintering temperature of 1150 ℃ for 6 hours to obtain a sintered material Li 6.5 La 3 Zr 1.5 Ta 0.5 O 12 。
After the sintered material was pulverized, 5g of the pulverized sintered material was mixed with 50g of a solvent NMP (N-methylpyrrolidone), and 50g of zirconia balls (diameter: 1mm:3mm:5 mm=1:1:1) were charged into a ball mill pot to be pulverized, to obtain a solid electrolyte slurry. Then, the slurry is guided into a stirring tank of a nano sand mill to start sand grinding, and the sand grinding speed is 2000rpm/min for 2 hours to obtain nano solid electrolyte slurry;
and 6g of binder PVDF-HFP is added into the solid electrolyte slurry, the mixture is stirred for 60min at the constant temperature of 50 ℃, 5g of LiTFSI is added again after the mixture is uniformly dispersed, and the mixture is continuously stirred for 2h, so as to obtain the composite electrolyte slurry.
Ternary material NCM622, conductive agent SP and binder PVDF are weighed according to the mass ratio of 95:2.5:2.5, and then an appropriate amount of NMP is added for homogenization, so that positive electrode slurry (the solid content is about 75 wt%) is obtained. The slurry is coated on the surface of an aluminum foil with the thickness of 75 mu m, and then is dried for 2 hours at the temperature of 50 ℃ by air blast drying (the mass content of the solvent in the positive electrode composite slurry is 10 wt%) to obtain the positive electrode plate.
The composite electrolyte slurry is uniformly coated on the surface of the positive electrode plate, and the thickness is 20 mu m. And drying for 2 hours at 60 ℃ in a forced air oven, and then drying for 12 hours at 80 ℃ in a vacuum oven to obtain the composite positive electrode plate.
And rolling the composite positive pole piece at 75 ℃, cutting the composite positive pole piece, and finally placing the composite positive pole piece into a vacuum oven for standby.
The particle size distribution of the nano solid electrolyte material described in example 1 is: d10 =67 nm, d50=140 nm, d90=511 nm.
Example 2
According to Li 6.5 La 3 Zr 1.5 Nb 0.5 O 12 Weighing 150g of lithium carbonate (the lithium source is excessive by 20wt%), lanthanum oxide, zirconium oxide and niobium pentoxide mixed raw materials, putting 150g of zirconium oxide balls (the diameter is 3mm:5mm:8 mm=1:1:1) into a ball milling tank, uniformly mixing to obtain a mixed material, putting the mixed material into a corundum crucible, and calcining the mixed material in a muffle furnace at a calcining temperature of 900 ℃ for 6 hours to obtain a calcined material;
100g of the calcined material is crushed by a crusher, and then 300g of the calcined material and zirconia balls (with the diameter of 1mm:3mm:5 mm=1:1:1) are put into a ball milling tank for grinding, the grinding material is put into a corundum crucible and is sintered for 6 hours at the sintering temperature of 1150 ℃ to obtain a sintered material Li 6.5 La 3 Zr 1.5 Nb 0.5 O 12 。
After the sintered material was pulverized, 5g of the pulverized sintered material was mixed with 50g of NMP as a solvent, and 50g of zirconia balls (diameter: 1mm:3mm:5 mm=1:1:1) were charged into a ball mill pot to be pulverized, to thereby obtain a solid electrolyte slurry. Then, the slurry is guided into a stirring tank of a nano sand mill to start sand grinding, and the sand grinding speed is 2000rpm/min for 2 hours to obtain nano solid electrolyte slurry;
and 6g of binder PVDF-HFP is added into the solid electrolyte slurry, the mixture is stirred for 60min at the constant temperature of 50 ℃, 5g of LiTFSI is added again after the mixture is uniformly dispersed, and the mixture is continuously stirred for 2h, so as to obtain the composite electrolyte slurry.
Ternary material NCM622, conductive agent SP and binder PVDF are weighed according to the mass ratio of 95:2.5:2.5, and then an appropriate amount of NMP is added for homogenization, so that positive electrode slurry (the solid content is about 75 wt%) is obtained. The slurry is coated on the surface of an aluminum foil with the thickness of 75 mu m, and then dried for 2 hours at the temperature of 50 ℃ by air blast drying (the mass content of the solvent in the positive electrode composite slurry is about 10 wt%) to obtain the positive electrode plate.
The composite electrolyte slurry is uniformly coated on the surface of the positive electrode plate, and the thickness is 20 mu m. And drying for 2 hours at 60 ℃ in a forced air oven, and then drying for 12 hours at 80 ℃ in a vacuum oven to obtain the composite positive electrode plate.
And rolling the composite positive pole piece at 75 ℃, cutting the composite positive pole piece, and finally placing the composite positive pole piece into a vacuum oven for standby.
Example 3
The thickness of the positive electrode composite paste coated on the positive electrode current collector in this example was 150 μm, and other operation steps and conditions were the same as in example 1.
Example 4
The thickness of the positive electrode composite paste coated on the positive electrode current collector in this example was 300 μm, and other operation steps and conditions were the same as in example 1.
Example 5
In this example, the coating thickness of the composite electrolyte paste was 50. Mu.m, and the other steps and conditions were the same as in example 1.
Example 6
The mass ratio of the solid electrolyte sintered material to NMP in this example is 1:20, i.e., 100g of NMP solvent was added, the other procedure and conditions were as in example 1.
Example 7
The mass ratio of the solid electrolyte sintered material to NMP in this example is 1:5, 25g of NMP solvent was added, and the other procedures and conditions were the same as in example 1.
Comparative example 1
The comparative example is different from example 1 in that after the NCM622 positive electrode slurry is coated on the surface of the aluminum foil, the aluminum foil is dried at 80 ℃ for 12 hours, after the positive electrode sheet is completely dried, the surface of the positive electrode sheet is coated with the composite electrolyte slurry, and then the composite positive electrode sheet is obtained by drying. The specific operation is as follows:
according to Li 6.5 La 3 Zr 1.5 Ta 0.5 O 12 Weighing 150g of lithium carbonate (with 20 percent of excessive lithium source), lanthanum oxide, zirconium oxide and tantalum pentoxide mixed raw materials, putting 150g of zirconium oxide balls (with the diameter of 3mm:5mm:8 mm=1:1:1) into a ball milling tank, uniformly mixing to obtain a mixed material, putting the mixed material into a corundum crucible, and calcining in a muffle furnace at the calcining temperature of 900 ℃ for 6 hours to obtain a calcined material;
100g of the calcined material is crushed by a crusher, and then 300g of the calcined material and zirconia balls (with the diameter of 1mm:3mm:5 mm=1:1:1) are put into a ball milling tank for grinding, the grinding material is put into a corundum crucible, and the corundum crucible is sintered in a muffle furnace at the sintering temperature of 1150 ℃ for 6 hours to obtain a sintered material Li 6.5 La 3 Zr 1.5 Ta 0.5 O 12 。
After the sintered material was pulverized, 5g of the pulverized sintered material was mixed with 50g of NMP as a solvent, and 50g of zirconia balls (diameter: 1mm:3mm:5 mm=1:1:1) were charged into a ball mill pot to be pulverized, to thereby obtain a solid electrolyte slurry. Then, the slurry is guided into a stirring tank of a nano sand mill to start sand grinding, and the sand grinding speed is 2000rpm/min for 2 hours to obtain nano solid electrolyte slurry;
and 6g of binder PVDF-HFP is added into the solid electrolyte slurry, the mixture is stirred for 60min at the constant temperature of 50 ℃, 5g of LiTFSI is added again after the mixture is uniformly dispersed, and the mixture is continuously stirred for 2h, so as to obtain the composite electrolyte slurry.
Ternary material NCM622, conductive agent SP and binder PVDF are weighed according to the proportion of 95:2.5:2.5, and then an appropriate amount of NMP is added for homogenization, so that positive electrode slurry is obtained. Coating the slurry on the surface of an aluminum foil with the thickness of 75 mu m, and then drying the aluminum foil for 12 hours by blowing at 80 ℃ to obtain the positive electrode plate.
The composite electrolyte slurry is uniformly coated on the surface of the positive electrode plate, and the thickness is 20 mu m. And putting the composite anode sheet into a blast oven again to be dried for 2 hours at 80 ℃, and then putting the composite anode sheet into a vacuum oven to be dried for 12 hours at 80 ℃ to obtain the composite anode sheet.
And rolling the composite positive pole piece at 75 ℃, cutting the composite positive pole piece, and finally placing the composite positive pole piece into a vacuum oven for standby.
Test case
Examples and comparative examples materials Performance test
And (3) manufacturing a battery: and the composite positive pole piece prepared in each example and comparative example is directly assembled with a negative pole to obtain the lithium ion battery for rate performance test, and no diaphragm is required to be added. Wherein the composition of the negative electrode is 95wt% of graphite, 2wt% of conductive carbon black and 3wt% of binder.
< rate Performance and cycle Performance test >
The batteries assembled by the composite positive pole pieces of the example and the comparative example 1 prepared by the method are placed in a blue-electricity multifunctional test channel at room temperature to test the multiplying power performance and the cycle performance of the batteries respectively. The rate test procedure was 0.2C charged and then discharged at 0.2C, 0.5C, 1C, 3C and 5C, each cycle 3 times, with a charging range of 2.8V-4.3V. The cycle performance test procedure was 0.2C charge and discharge 3 times, then 100 times at 1C. Typically, taking examples 1-2 as an example, the multiplying power test results are shown in fig. 1, the cycling test results are shown in fig. 2, and the performance test results of examples 3-7 are similar to those of example 1.
As can be seen from fig. 1 and 2, the rate performance of both examples 1 and 2 is significantly better than that of comparative example 1, mainly because the interfacial resistance of examples 1 and 2 is smaller than that of comparative example 1 (i.e., the mixture layer of solid electrolyte and positive electrode slurry is not formed at the interface), the lithium ion transmission rate can be greatly improved by forming the mixture layer of solid electrolyte and positive electrode slurry at the interface, and the positive electrode and electrolyte are more tightly combined, so that the rate performance and cycle performance are improved to some extent.
< test of impedance value >
The button cells are directly assembled by the composite positive pole piece and the metal lithium piece of the example and the comparative example 1 prepared by the method, and the impedance values of the button cells are respectively measured by adopting an alternating current impedance test method. Specifically, the button cell for test is placed in a Chen-Hua electrochemical workstation CHI660E to test alternating current impedance in a 3.7V charging state after being circulated for three times at 2.8V-4.3 V@0.2C, the frequency is set to be 0.1 HZ-0.1 MHZ, and the voltage amplitude is set to be 5mV. Typically, taking examples 1-2 as an example, the experimental results are shown in FIG. 3, and the performance test results of examples 3-7 are similar to those of example 1.
As can be seen from fig. 3, the composite electrodes of examples 1 and 2, which were obtained by directly coating the LLZO solid electrolyte in an incompletely dried state during the fabrication of the NCM622 positive electrode sheet, had significantly reduced interfacial resistance compared with comparative example 1 (i.e., no mixture layer of solid electrolyte and positive electrode slurry was formed at the interface), indicating that the process was significantly improved over that of comparative example 1, which was also a reason for being able to improve the rate performance.
According to the modification method disclosed by the invention, the interface impedance can be obviously reduced by directly coating the LLZO solid electrolyte in an incompletely dried state in the manufacturing process of the positive electrode plate, and the lithium ion transmission efficiency and the interface stability of the positive electrode material are improved, so that the rate performance and the cycle life of the lithium ion battery are effectively improved.
The foregoing is merely a preferred embodiment of the present invention, and it should be noted that modifications and additions may be made to those skilled in the art without departing from the method of the present invention, which modifications and additions are also to be considered as within the scope of the present invention.
Industrial applicability
The composite positive electrode plate provided by the invention has no clear interface between the positive electrode composite material layer and the composite electrolyte layer, so that the interface impedance between the positive electrode composite material layer and the composite electrolyte layer is reduced, and the solid electrolyte is not easy to fall off from the positive electrode plate. According to the invention, the positive electrode composite slurry is not completely dried, and then the solid electrolyte slurry is coated, so that the solid electrolyte slurry and the positive electrode slurry are compounded, the interface impedance between the solid electrolyte slurry and the positive electrode slurry is reduced, and the performance of the battery cell is improved. The method is simple and convenient, has lower production cost and is easy to industrialize.
Claims (11)
1. A composite positive plate is characterized in that,
the composite positive plate comprises a positive composite material layer and a composite electrolyte layer which are sequentially formed on the surface of a positive current collector,
wherein a mixture layer of the positive electrode composite material and the composite electrolyte is formed at the interface of the positive electrode composite material layer and the composite electrolyte layer.
2. The composite positive electrode sheet of claim 1, wherein the positive electrode composite material layer comprises a positive electrode material, a conductive agent, a first binder; the composite electrolyte layer includes a solid electrolyte, a second binder, and a lithium salt; wherein the first binder and the second binder are the same or different.
3. The composite positive electrode sheet according to claim 2, wherein the positive electrode material is selected from one or more of lithium cobaltate, lithium iron phosphate, lithium iron manganese phosphate, lithium nickel cobalt manganate and lithium manganate;
the solid electrolyte is selected from one or more of an oxide solid electrolyte, a NASICON type solid electrolyte, and a LISICON type solid electrolyte.
4. The composite positive electrode sheet according to claim 3, wherein the oxide solid electrolyte is selected from at least one of garnet-type oxide solid electrolyte and perovskite-type oxide solid electrolyte.
5. The composite positive electrode sheet according to claim 4, wherein the garnet-type oxide solid electrolyte has a chemical composition of Li 7-3x A x La 3 Zr 2-y B y O 12 Wherein the doping element A is Ga and/or Al, the doping element B is one or more of Zn, ta, nb, W, mg, ca, sr, si, x is more than or equal to 0 and less than or equal to 1.0, and y is more than or equal to 0 and less than or equal to 1.0;
the perovskite oxide solid electrolyte is LLTO.
6. The preparation method of the composite positive plate is characterized by comprising the following steps:
step S1: coating the positive electrode composite slurry on a positive electrode current collector, and drying the positive electrode composite slurry;
step S2: and before the positive electrode composite slurry is completely dried, coating the composite electrolyte slurry on the incompletely dried positive electrode composite slurry, and drying to form a mixture layer of the positive electrode composite material and the composite electrolyte at the interface of the positive electrode composite material layer and the composite electrolyte layer, thereby obtaining the composite positive electrode sheet.
7. The production method according to claim 6, wherein a thickness of the positive electrode composite slurry coated on the positive electrode current collector is 10 μm or more and 500 μm or less;
preferably, the thickness of the composite electrolyte slurry is 8 μm or more and 100 μm or less coated on the incompletely dried positive electrode composite slurry;
preferably, the thickness of the composite electrolyte slurry is smaller than the thickness of the positive electrode composite slurry;
preferably, the step S1 includes: coating the positive electrode composite slurry on a positive electrode current collector, and drying until the solvent content in the positive electrode composite slurry is 1-20% by mass, so as to obtain a positive electrode plate; or,
in the step S1, the drying temperature is 30-50 ℃ and the drying time is 0.5-12 h;
preferably, the temperature of the drying in the step S2 is room temperature to 100 ℃ and the time is 1 to 12 hours.
8. The production method according to claim 6 or 7, wherein the positive electrode composite slurry is obtained by mixing and homogenizing a positive electrode material, a conductive agent, a first binder, and a first solvent;
preferably, the composite electrolyte slurry is obtained by mixing a solid electrolyte slurry obtained by mixing a sintered material of a solid electrolyte with a second solvent, followed by ball milling and sand milling, a second binder, and a lithium salt;
preferably, the mass ratio of the sintering material of the solid electrolyte to the second solvent is 1:3-1:20, a step of;
preferably, the solid electrolyte in the solid electrolyte slurry has a particle diameter D90 of 200nm to 1 μm.
9. The production method according to claim 8, wherein the first solvent and the second solvent are each selected from organic solvents, and the first solvent and the second solvent are mutually soluble;
preferably, the first solvent and the second solvent are selected from N, N-dimethylformamide and/or N-methylpyrrolidone.
10. The production method according to claim 8 or 9, wherein the sintered material of the solid electrolyte is obtained by the steps of:
weighing raw material powder according to a stoichiometric ratio, ball-milling and mixing, and calcining to obtain a calcined material;
crushing and ball milling the calcined material to obtain a ball grinding material;
and sintering the ball milling material to obtain a sintered material.
11. A lithium battery characterized in that it comprises a composite positive electrode sheet according to any one of claims 1 to 5 or a composite positive electrode sheet obtained by the production method according to any one of claims 6 to 10.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211724123.0A CN116053401A (en) | 2022-12-30 | 2022-12-30 | Composite positive electrode plate, preparation method thereof and lithium battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211724123.0A CN116053401A (en) | 2022-12-30 | 2022-12-30 | Composite positive electrode plate, preparation method thereof and lithium battery |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116053401A true CN116053401A (en) | 2023-05-02 |
Family
ID=86117824
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211724123.0A Pending CN116053401A (en) | 2022-12-30 | 2022-12-30 | Composite positive electrode plate, preparation method thereof and lithium battery |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116053401A (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110120510A (en) * | 2019-05-23 | 2019-08-13 | 桑德新能源技术开发有限公司 | A kind of all-solid-state battery and preparation method thereof |
| CN110380133A (en) * | 2019-08-02 | 2019-10-25 | 中南大学 | A kind of transition zone design method of inorganic solid electrolyte and positive interpolar |
| WO2020059550A1 (en) * | 2018-09-18 | 2020-03-26 | 富士フイルム株式会社 | Production method for all-solid secondary battery layered member, and production method for all-solid secondary battery |
| CN111987348A (en) * | 2020-08-27 | 2020-11-24 | 电子科技大学 | Preparation method of NASICON type solid-state battery |
| CN112186262A (en) * | 2020-10-09 | 2021-01-05 | 西安交通大学 | MLCC structure-based all-solid-state lithium ion battery and preparation method thereof |
| CN113690499A (en) * | 2021-07-30 | 2021-11-23 | 东莞凯德新能源有限公司 | Composite positive plate and lithium ion battery comprising same |
-
2022
- 2022-12-30 CN CN202211724123.0A patent/CN116053401A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2020059550A1 (en) * | 2018-09-18 | 2020-03-26 | 富士フイルム株式会社 | Production method for all-solid secondary battery layered member, and production method for all-solid secondary battery |
| CN110120510A (en) * | 2019-05-23 | 2019-08-13 | 桑德新能源技术开发有限公司 | A kind of all-solid-state battery and preparation method thereof |
| CN110380133A (en) * | 2019-08-02 | 2019-10-25 | 中南大学 | A kind of transition zone design method of inorganic solid electrolyte and positive interpolar |
| CN111987348A (en) * | 2020-08-27 | 2020-11-24 | 电子科技大学 | Preparation method of NASICON type solid-state battery |
| CN112186262A (en) * | 2020-10-09 | 2021-01-05 | 西安交通大学 | MLCC structure-based all-solid-state lithium ion battery and preparation method thereof |
| CN113690499A (en) * | 2021-07-30 | 2021-11-23 | 东莞凯德新能源有限公司 | Composite positive plate and lithium ion battery comprising same |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106575761B (en) | Positive electrode active material for nonaqueous electrolyte secondary battery and method for producing same | |
| CN110718688B (en) | Single crystal ternary positive electrode material and preparation method thereof | |
| US10763506B2 (en) | Method of manufacturing positive electrode material for electrical storage device | |
| EP4024519A1 (en) | Positive electrode material, preparation method therefor and lithium ion battery | |
| KR20150090963A (en) | Positive electrode active material for rechargable lithium battery, method for synthesis the same, and rechargable lithium battery including the same | |
| CN110574208A (en) | All-solid-state battery | |
| CN107017387A (en) | It is a kind of for composite positive pole of solid lithium ion battery and preparation method thereof | |
| CN110904495A (en) | Preparation method of monocrystal polyhedral lithium manganate positive electrode material | |
| KR20120089382A (en) | Lithuium manganese complex oxide and the manufacturing method thereof | |
| KR20220127242A (en) | Positive electrode active material for all-solid-state lithium-ion battery, electrode and all-solid-state lithium-ion battery | |
| CN104852041A (en) | Nickel-cobalt-aluminum lithium battery positive electrode material preparation method and lithium battery positive electrode material | |
| JP2022189427A (en) | Positive electrode active material for lithium secondary battery, positive electrode for lithium secondary battery, and lithium secondary battery | |
| CN115386946A (en) | Preparation method of long-cycle high-nickel single crystal positive electrode material | |
| CN105529457A (en) | Industrial production method for highly compacted 3.7 g/cm3 lithium nickel cobalt manganese oxide NCM523 ternary cathode material | |
| CN113845152A (en) | Lithium nickel manganese oxide positive electrode material, preparation method thereof and lithium ion battery | |
| KR20220129544A (en) | Positive electrode active material for all-solid-state lithium-ion battery, electrode and all-solid-state lithium-ion battery | |
| KR101537067B1 (en) | Solid electrolyte for all solid state rechargeable lithium battery, method for preparing the same, and all solid state rechargeable lithium battery including the same | |
| CN112670500A (en) | High-compaction fast-charging positive electrode material and preparation method thereof | |
| CN113013389A (en) | Ternary positive electrode material coated with manganese oxide compound and preparation method thereof | |
| CN107834054B (en) | Preparation method of lithium nickel manganese oxide-graphene composite material for lithium ion battery | |
| CN113690431B (en) | Lithium manganate positive electrode material, preparation method, improvement method and application thereof | |
| CN116053401A (en) | Composite positive electrode plate, preparation method thereof and lithium battery | |
| CN107611447A (en) | A kind of lithium ion battery collector and preparation method thereof, lithium ion battery pole piece and lithium ion battery | |
| US8889297B2 (en) | Nanocomposite cathode active material for lithium secondary batteries, method for preparing the same and lithium secondary batteries comprising the same | |
| CN113666430A (en) | Lithium-rich cathode material, preparation method thereof and lithium ion battery |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |