CN115621461A - Positive electrode lithium supplement agent, preparation method thereof, positive electrode piece and battery - Google Patents
Positive electrode lithium supplement agent, preparation method thereof, positive electrode piece and battery Download PDFInfo
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- CN115621461A CN115621461A CN202211255244.5A CN202211255244A CN115621461A CN 115621461 A CN115621461 A CN 115621461A CN 202211255244 A CN202211255244 A CN 202211255244A CN 115621461 A CN115621461 A CN 115621461A
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- positive electrode
- lithium
- battery
- lithium supplement
- temperature
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- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 157
- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 157
- 239000013589 supplement Substances 0.000 title claims abstract description 108
- 238000002360 preparation method Methods 0.000 title claims abstract description 25
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 78
- 239000000463 material Substances 0.000 claims abstract description 44
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 43
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 30
- 238000005229 chemical vapour deposition Methods 0.000 claims abstract description 30
- 239000002243 precursor Substances 0.000 claims abstract description 22
- 238000007740 vapor deposition Methods 0.000 claims abstract description 11
- 238000000151 deposition Methods 0.000 claims abstract description 8
- 238000000034 method Methods 0.000 claims description 38
- 238000001035 drying Methods 0.000 claims description 31
- 238000001816 cooling Methods 0.000 claims description 30
- 230000003197 catalytic effect Effects 0.000 claims description 26
- 239000006258 conductive agent Substances 0.000 claims description 19
- 230000008569 process Effects 0.000 claims description 19
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 17
- 239000002002 slurry Substances 0.000 claims description 17
- 239000011248 coating agent Substances 0.000 claims description 16
- 238000000576 coating method Methods 0.000 claims description 16
- 239000011230 binding agent Substances 0.000 claims description 15
- 229910003002 lithium salt Inorganic materials 0.000 claims description 15
- 159000000002 lithium salts Chemical class 0.000 claims description 15
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 15
- 239000007774 positive electrode material Substances 0.000 claims description 15
- 230000001502 supplementing effect Effects 0.000 claims description 12
- 239000003960 organic solvent Substances 0.000 claims description 11
- 239000002904 solvent Substances 0.000 claims description 11
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 9
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 9
- 239000002033 PVDF binder Substances 0.000 claims description 9
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 9
- 238000006243 chemical reaction Methods 0.000 claims description 9
- 239000011259 mixed solution Substances 0.000 claims description 9
- 238000002156 mixing Methods 0.000 claims description 9
- -1 polytetrafluoroethylene Polymers 0.000 claims description 9
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 9
- 238000003756 stirring Methods 0.000 claims description 8
- 239000000243 solution Substances 0.000 claims description 7
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 claims description 6
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 claims description 6
- 239000003575 carbonaceous material Substances 0.000 claims description 6
- KAKZBPTYRLMSJV-UHFFFAOYSA-N Butadiene Chemical compound C=CC=C KAKZBPTYRLMSJV-UHFFFAOYSA-N 0.000 claims description 5
- 239000001768 carboxy methyl cellulose Substances 0.000 claims description 5
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 claims description 5
- 229910021392 nanocarbon Inorganic materials 0.000 claims description 5
- 238000003825 pressing Methods 0.000 claims description 5
- 229920000049 Carbon (fiber) Polymers 0.000 claims description 4
- DPXJVFZANSGRMM-UHFFFAOYSA-N acetic acid;2,3,4,5,6-pentahydroxyhexanal;sodium Chemical compound [Na].CC(O)=O.OCC(O)C(O)C(O)C(O)C=O DPXJVFZANSGRMM-UHFFFAOYSA-N 0.000 claims description 4
- 239000013543 active substance Substances 0.000 claims description 4
- 239000004917 carbon fiber Substances 0.000 claims description 4
- 239000002134 carbon nanofiber Substances 0.000 claims description 4
- 239000002041 carbon nanotube Substances 0.000 claims description 4
- 229910021393 carbon nanotube Inorganic materials 0.000 claims description 4
- 229910021389 graphene Inorganic materials 0.000 claims description 4
- 229910002804 graphite Inorganic materials 0.000 claims description 4
- 239000010439 graphite Substances 0.000 claims description 4
- 239000003273 ketjen black Substances 0.000 claims description 4
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 4
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 4
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 claims description 4
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 claims description 4
- 238000001694 spray drying Methods 0.000 claims description 4
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 claims description 3
- 239000005977 Ethylene Substances 0.000 claims description 3
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 claims description 3
- 229920003171 Poly (ethylene oxide) Polymers 0.000 claims description 3
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 claims description 3
- 229920001577 copolymer Polymers 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
- 125000002534 ethynyl group Chemical group [H]C#C* 0.000 claims description 3
- 238000007755 gap coating Methods 0.000 claims description 3
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical group [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 claims description 3
- 229910052808 lithium carbonate Inorganic materials 0.000 claims description 3
- 229920000036 polyvinylpyrrolidone Polymers 0.000 claims description 3
- 239000001267 polyvinylpyrrolidone Substances 0.000 claims description 3
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 claims description 3
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 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 2
- 238000000354 decomposition reaction Methods 0.000 abstract description 35
- 230000000694 effects Effects 0.000 abstract description 17
- 239000000126 substance Substances 0.000 abstract description 12
- 238000002844 melting Methods 0.000 abstract description 9
- 230000008018 melting Effects 0.000 abstract description 9
- 230000008859 change Effects 0.000 abstract description 8
- 238000012986 modification Methods 0.000 abstract description 8
- 230000004048 modification Effects 0.000 abstract description 8
- 230000000052 comparative effect Effects 0.000 description 31
- 238000004519 manufacturing process Methods 0.000 description 12
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 10
- 229910001416 lithium ion Inorganic materials 0.000 description 10
- 238000007600 charging Methods 0.000 description 9
- 239000003792 electrolyte Substances 0.000 description 9
- 230000008901 benefit Effects 0.000 description 7
- 239000012528 membrane Substances 0.000 description 6
- 238000012545 processing Methods 0.000 description 6
- FMLZGWFPVTXRBT-UHFFFAOYSA-N [Li].[C]=O Chemical compound [Li].[C]=O FMLZGWFPVTXRBT-UHFFFAOYSA-N 0.000 description 5
- JRNVUTLFWMKTEB-UHFFFAOYSA-N [O-2].[Li+].[C+4] Chemical compound [O-2].[Li+].[C+4] JRNVUTLFWMKTEB-UHFFFAOYSA-N 0.000 description 5
- 238000007599 discharging Methods 0.000 description 5
- 239000007773 negative electrode material Substances 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- 239000010405 anode material Substances 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- 230000006872 improvement Effects 0.000 description 4
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 239000006227 byproduct Substances 0.000 description 3
- 230000003247 decreasing effect Effects 0.000 description 3
- 230000008021 deposition Effects 0.000 description 3
- 230000014759 maintenance of location Effects 0.000 description 3
- 239000007784 solid electrolyte Substances 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- FGVSFIHWBGAHTM-UHFFFAOYSA-N [O].[C].[Li] Chemical compound [O].[C].[Li] FGVSFIHWBGAHTM-UHFFFAOYSA-N 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 229960004424 carbon dioxide Drugs 0.000 description 2
- 229910002090 carbon oxide Inorganic materials 0.000 description 2
- 239000003054 catalyst Substances 0.000 description 2
- 239000010406 cathode material Substances 0.000 description 2
- 239000011888 foil Substances 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000000227 grinding Methods 0.000 description 2
- 230000002427 irreversible effect Effects 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 239000002985 plastic film Substances 0.000 description 2
- 229920006255 plastic film Polymers 0.000 description 2
- 230000002035 prolonged effect Effects 0.000 description 2
- 229910052814 silicon oxide Inorganic materials 0.000 description 2
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910010699 Li5FeO4 Inorganic materials 0.000 description 1
- 229910000572 Lithium Nickel Cobalt Manganese Oxide (NCM) Inorganic materials 0.000 description 1
- 239000004952 Polyamide Substances 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 239000004642 Polyimide Substances 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- FBDMTTNVIIVBKI-UHFFFAOYSA-N [O-2].[Mn+2].[Co+2].[Ni+2].[Li+] Chemical compound [O-2].[Mn+2].[Co+2].[Ni+2].[Li+] FBDMTTNVIIVBKI-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 239000004760 aramid Substances 0.000 description 1
- 229920003235 aromatic polyamide Polymers 0.000 description 1
- 229910021383 artificial graphite Inorganic materials 0.000 description 1
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 1
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 238000010277 constant-current charging Methods 0.000 description 1
- 239000011889 copper foil Substances 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 239000011883 electrode binding agent Substances 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 238000007765 extrusion coating Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 238000007756 gravure coating Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000008595 infiltration Effects 0.000 description 1
- 238000001764 infiltration Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229910000625 lithium cobalt oxide Inorganic materials 0.000 description 1
- 229910002102 lithium manganese oxide Inorganic materials 0.000 description 1
- BFZPBUKRYWOWDV-UHFFFAOYSA-N lithium;oxido(oxo)cobalt Chemical compound [Li+].[O-][Co]=O BFZPBUKRYWOWDV-UHFFFAOYSA-N 0.000 description 1
- VLXXBCXTUVRROQ-UHFFFAOYSA-N lithium;oxido-oxo-(oxomanganiooxy)manganese Chemical compound [Li+].[O-][Mn](=O)O[Mn]=O VLXXBCXTUVRROQ-UHFFFAOYSA-N 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000002923 metal particle Substances 0.000 description 1
- CSJDCSCTVDEHRN-UHFFFAOYSA-N methane;molecular oxygen Chemical compound C.O=O CSJDCSCTVDEHRN-UHFFFAOYSA-N 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910021382 natural graphite Inorganic materials 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 229920002239 polyacrylonitrile Polymers 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 229920000139 polyethylene terephthalate Polymers 0.000 description 1
- 239000005020 polyethylene terephthalate Substances 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000007650 screen-printing Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 230000009469 supplementation Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
- H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—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
- 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
- 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
-
- 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
Abstract
The invention discloses a positive electrode lithium supplement agent, a preparation method thereof, a positive electrode plate and a battery, and relates to the technical field of batteries; the preparation method comprises the steps of depositing a carbon source on the surface of a positive electrode lithium supplement agent precursor in a low-temperature vapor deposition mode; the positive electrode lithium supplement precursor comprises a lithium oxycarbide. On one hand, the carbon source is adopted to modify the precursor of the positive electrode lithium supplement agent, so that the lithium supplement effect can be provided, the energy density of the battery is ensured, and the voltage window of the positive electrode lithium supplement agent can be effectively reduced, so that the decomposition voltage of the material is reduced, and the stability and the cycle performance of the battery are improved; on the other hand, modification is carried out in a low-temperature chemical vapor deposition mode, and low-temperature vapor deposition is matched with the low-melting-point lithium oxycarbide, so that melting or chemical change of the material caused by high-temperature treatment is avoided, a carbon source can be ensured to uniformly and stably wrap the surface of the lithium oxycarbide, the decomposition voltage of the material can be further reduced, and the stability and the cycle performance of the battery can be ensured.
Description
Technical Field
The invention relates to the technical field of batteries, in particular to a positive electrode lithium supplement agent, a preparation method thereof, a positive electrode plate and a battery.
Background
With the wide application of lithium ion batteries in the fields of 3C, electric vehicles and energy storage, further improvement of the energy density of lithium ion batteries is imminent. However, since the first coulombic efficiency of the conventional cathode material is much higher than that of the anode material, and a solid electrolyte membrane is formed on the surface of the anode material in the first charging process, the capacity of the cathode material cannot be fully exerted, and more lithium ions are consumed, so that the overall energy density of the battery is reduced. For this reason, a lithium replenishing operation is required to replenish lithium ions consumed in the formation of the solid electrolyte membrane by the anode material.
The lithium supplement of the negative electrode is a common lithium supplement mode, generally, lithium powder or a lithium belt is directly compounded on the surface of a negative electrode pole piece, but the lithium supplement process of the negative electrode is complicated, the equipment cost is high, the production environment is severe, the danger is high, the uniformity is difficult to control, the consistency of the battery is poor, and the practical production application is difficult. For this reason, the prior art has been developed to supplement lithium to the positive electrode. The anode lithium supplement adopts the anode lithium supplement additive to supplement lithium to the anode of the battery, and compared with the cathode lithium supplement, the process is relatively simple.
In detail, in the scheme of lithium supplement for the positive electrode, for example, CN109546226A mentions a lithium supplement substance Li5FeO4, which has a high residual alkali value, and the high residual alkali reacts with positive electrode binder polyvinylidene fluoride (PVDF), so that chemical gel is easily generated in the process of stirring the slurry, the viscosity of the slurry is increased, and the processing of the pole piece is affected. In addition, although the battery cell capacity is obviously improved, the residual of non-lithium source components in the lithium supplement substance is caused, more impurities are left, and the problems of serious battery cell self-discharge, reduced discharge capacity and the like are caused. Li as mentioned in CN112151889A 3 N has higher theoretical gram capacity, no by-product residue after decomposition does not affect the structure and performance of the battery, but Li 3 N is unstable to airAnd has higher requirements on processing environment.
In order to solve the problems, the prior art adopts a scheme of lithium oxycarbide for lithium supplement, and the lithium oxycarbide has low requirements on processing environment, relatively low cost and excellent safety, and is an excellent positive electrode lithium supplement agent. However, the lithium oxycarbide has poor conductivity and high decomposition potential (usually above 4.4V), and it needs to be charged to a high potential in the first charging cycle to release its capacity so as to exert the lithium supplementing effect of the lithium supplementing agent. When the carbon oxide lithium is matched with a positive electrode material, particularly a ternary material, the higher the charging voltage is, the larger the irreversible change of the positive electrode structure is, and the structural stability and the cycle performance of the lithium ion battery can be seriously influenced.
In view of the above, the present invention is particularly proposed.
Disclosure of Invention
The invention aims to provide a positive electrode lithium supplement agent with low decomposition voltage and a preparation method thereof, which can provide lithium supplement effect, ensure the energy density of a battery and effectively improve the stability and the cycle performance of the battery.
The invention also aims to provide a positive pole piece and a battery, which comprise the positive pole lithium supplement agent. Therefore, it also has advantages of high energy density, high stability and high cycle performance.
The embodiment of the invention is realized by the following steps:
in a first aspect, the present invention provides a method for preparing a positive electrode lithium supplement agent, comprising:
depositing a carbon source on the surface of the positive electrode lithium supplement precursor in a low-temperature vapor deposition mode; wherein, the positive electrode lithium supplement agent precursor comprises carbon lithium oxide.
In an optional embodiment, the low-temperature vapor deposition is carried out in a reaction chamber of a chemical vapor deposition device with a cooling device, and a carbon source forms a nano-carbon material after passing through a catalytic chamber in the reaction chamber and is deposited on the surface of a positive electrode lithium supplement precursor;
wherein the temperature of the cooling device is-30 to-20 ℃, the temperature of the catalytic chamber is 300 to 1000 ℃, and the chemical vapor deposition time is 0.5 to 12 hours.
In an alternative embodiment, the temperature of the cooling device is-30 to-25 ℃, the temperature of the catalytic chamber is 400 to 900 ℃, and the chemical vapor deposition time is 4 to 8 hours.
In alternative embodiments, the lithium oxycarbide comprises Li 2 C 2 O 4 、Li 2 C 4 O 4 And Li 2 CO 3 At least one of (a);
and/or the presence of a gas in the gas,
the carbon source includes at least one of ethanol, methanol, toluene, methane, ethylene, and acetylene.
In an alternative embodiment, the positive electrode lithium supplement precursor is prepared by the following steps:
mixing lithium salt and an organic solvent to obtain a mixed solution, wherein the lithium salt is a lithium carbonate;
and sanding and drying the mixed solution in sequence.
In alternative embodiments, the organic solvent comprises at least one of ethanol, N-methylpyrrolidone, N-dimethylformamide, tetrahydrofuran;
and/or the mass ratio of the lithium salt to the organic solvent is 1 (0.5-5), stirring is carried out during the mixing process, and the stirring speed is 500-1500rmp;
and/or in the sanding step, the granularity D50 of the solution is less than 2 mu m, the sanding frequency is 500-1200Hz, and the sanding time is 6-12h;
and/or in the drying step, the drying mode is air blast drying or spray drying, the drying temperature is 80-230 ℃, and the drying time is 6-12h.
In a second aspect, the present invention provides a positive electrode lithium supplement prepared by the method for preparing a positive electrode lithium supplement according to any one of the foregoing embodiments.
In a third aspect, the present invention provides a positive electrode plate, including:
a current collector;
the positive electrode active material layer is obtained by coating positive electrode active slurry on at least one side of a current collector in the thickness direction and performing cold pressing and drying, and the positive electrode active slurry comprises a positive electrode active material, a conductive agent, a binder and a solvent, and the positive electrode lithium supplement agent prepared by the preparation method of the positive electrode lithium supplement agent in any one of the above embodiments, or the positive electrode lithium supplement agent in the above embodiments.
In an optional embodiment, in other components except the solvent of the positive electrode active slurry, the mass percentage of the positive electrode active substance is 80-97%, the mass percentage of the positive electrode lithium supplement agent is 2-16%, and the total mass percentage of the conductive agent and the binder is 1-4%;
and/or the positive active substance comprises at least one of a lithium nickel cobalt manganese oxide ternary material, a lithium iron phosphate material, a lithium manganese oxide material and a lithium cobalt oxide material;
and/or the conductive agent comprises at least one of conductive carbon black, conductive graphite, ketjen black, carbon fiber, carbon nanotube, graphene oxide and vapor grown carbon fiber;
and/or the binder comprises at least one of polyvinylpyrrolidone, polyvinylidene fluoride, polyethylene oxide, polytetrafluoroethylene, sodium carboxymethylcellulose, styrene and further a copolymer of butadiene;
and/or, the coating mode comprises any one of a continuous coating mode, a gap coating mode or a point coating mode.
In a fourth aspect, the present invention provides a battery, comprising the positive electrode plate of the foregoing embodiment.
Embodiments of the invention have at least the following advantages or benefits:
the preparation method of the positive electrode lithium supplement agent provided by the embodiment of the invention comprises the steps of depositing a carbon source on the surface of a precursor of the positive electrode lithium supplement agent in a low-temperature vapor deposition mode; wherein, the precursor of the positive electrode lithium supplement agent comprises carbon lithium oxide. On one hand, the carbon source is adopted to modify the precursor of the positive electrode lithium supplement agent, so that the lithium supplement effect can be provided, the energy density of the battery is ensured, and the voltage window of the positive electrode lithium supplement agent can be effectively reduced, so that the decomposition voltage of the material is reduced, and the stability and the cycle performance of the battery are improved; on the other hand, modification is carried out in a low-temperature chemical vapor deposition mode, and low-temperature vapor deposition is matched with the low-melting-point lithium oxycarbide, so that melting or chemical change of the material caused by high-temperature treatment is avoided, a carbon source can be ensured to uniformly and stably wrap the surface of the lithium oxycarbide, the decomposition voltage of the material can be further reduced, and the stability and the cycle performance of the battery can be ensured.
The embodiment of the invention provides a positive pole piece and a battery, which comprise the positive pole lithium supplement agent. Therefore, it also has advantages of high energy density, high stability and high cycle performance.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are conventional products which are not indicated by manufacturers and are commercially available.
The features and properties of the present invention are described in further detail below with reference to examples.
In the prior art, in order to ensure the energy density of the battery, lithium supplementation is generally needed to supplement lithium ions consumed by the negative electrode in the process of forming a solid electrolyte membrane during the first charging. The common lithium supplementing modes include negative electrode lithium supplementing and positive electrode lithium supplementing, because the process is simpler, the positive electrode lithium supplementing is frequently used, the carbon oxide lithium has low requirement on the processing environment, the cost is relatively lower, and the safety is excellent, so that the lithium supplementing agent is an excellent positive electrode lithium supplementing agent. However, the lithium oxycarbide has poor conductivity and high decomposition potential (usually above 4.4V), and it needs to be charged to a high potential in the first charging cycle to release its capacity so as to exert the lithium supplementing effect of the lithium supplementing agent. When the carbon oxide lithium compound is matched with a positive electrode material, particularly a ternary material, the higher the charging voltage is, the larger the irreversible change of the positive electrode structure is, and the structural stability and the cycle performance of the lithium ion battery can be seriously influenced.
In view of this, the present embodiment provides a positive electrode lithium supplement agent, a preparation method thereof, a positive electrode sheet, and a battery, which can stably reduce the decomposition voltage of a lithium oxycarbide by modifying the lithium oxycarbide, so as to reduce the change of a positive electrode structure in a use process, and effectively improve the stability and cycle performance of the battery while improving the energy density of the battery. The positive electrode lithium supplement agent, the preparation method thereof, the positive electrode plate and the battery are described in detail below.
The embodiment of the invention provides a positive electrode lithium supplement agent, which is prepared by the following method: depositing a carbon source on the surface of the positive electrode lithium supplement agent precursor in a low-temperature vapor deposition mode; wherein, the precursor of the positive electrode lithium supplement agent comprises carbon lithium oxide.
The positive electrode lithium supplement agent prepared by the method has the following effects:
(1) The carbon-oxygen chemical substance used by the positive electrode lithium supplement agent is easily available in source, low in alkalinity, low in requirement on the use environment and capable of reducing the manufacturing cost.
(2) After the positive electrode lithium supplement agent filled with carbon oxide in the positive electrode piece is formed, the positive electrode lithium supplement agent is decomposed into Li + And CO2, in which Li is decomposed + The lithium ions consumed by the SEI film formed during the first charge and discharge of the negative electrode can be supplemented, so that the first effect and the energy density of the battery can be improved, and the service life of the battery can be prolonged. Meanwhile, CO is a byproduct of decomposition of carbon oxide 2 And the negative pressure can be removed in the formation process, so that negative effects on the battery are not brought. And, CO 2 After the anode material is removed, a microporous structure can be formed, the microporous structure is more favorable for the infiltration of electrolyte, and the rate capability of the battery can be improved.
(3) The carbon source is adopted to modify the precursor of the positive electrode lithium supplement agent, so that the lithium supplement effect can be provided, the energy density of the battery is ensured, and the voltage window of the positive electrode lithium supplement agent can be effectively reduced, so that the decomposition voltage of the material is reduced, and the stability and the cycle performance of the battery are improved.
(4) The modification is carried out in a low-temperature chemical vapor deposition mode, the low-temperature chemical vapor deposition is matched with the lithium oxycarbide with a low melting point, the melting or chemical change of the material caused by high-temperature treatment is avoided, the carbon source can be ensured to uniformly and stably wrap the surface of the lithium oxycarbide, the decomposition voltage of the material can be further ensured to be reduced, and the stability and the cycle performance of the battery can be ensured.
In the embodiment of the present invention, the low-temperature chemical vapor deposition is performed in the reaction chamber of the chemical vapor deposition apparatus with a cooling device. And the carbon source forms a nano carbon material after passing through a catalytic chamber in the reaction chamber and is deposited on the surface of the positive electrode lithium supplement precursor. The temperature of the cooling device is-30 to-20 ℃, the temperature of the catalytic chamber is 300 to 1000 ℃, the chemical vapor deposition time is 0.5 to 12 hours, the catalytic chamber is a place where a catalyst decomposes and heats a carbon source, and a nano carbon material easy to deposit can be generated, so that the carbon source can be conveniently deposited on the surface of the lithium oxycarbide in vapor deposition, and the purpose of modifying the lithium oxycarbide is achieved, wherein the catalyst in the catalytic chamber can be selected from nano metal particles such as iron, cobalt, nickel and the like. The arrangement of the cooling device is beneficial to ensuring that the nano carbon material formed after passing through the catalytic chamber can be subjected to vapor deposition at a low temperature.
Because the melting point of the carbon lithium oxide is low, if the processing temperature is high, the structure of the carbon lithium oxide is easy to damage particularly when the coating mode is adopted for high-temperature processing, so that the lithium supplement operation effect is poor, and even the lithium supplement operation cannot be normally carried out. Therefore, in the embodiment of the invention, the arrangement of the cooling device can effectively reduce the deposition temperature, the deposition temperature is controlled in a lower range, the carbon source can be matched with the carbon-oxide lithium with a low melting point, the melting or chemical change of the material caused by high-temperature treatment is avoided, and the surface of the carbon-oxide lithium can be uniformly and stably wrapped by the carbon source, so that the decomposition voltage of the material can be further reduced, and the stability and the cycle performance of the battery can be ensured.
Optionally, in this embodiment, the temperature of the cooling device is-30 to-25 ℃, the temperature of the catalytic chamber is 400 to 900 ℃, and the chemical vapor deposition time is 4 to 8 hours. The cooling temperature and the catalysis temperature are controlled within the range, so that the structural and chemical changes of the material can be further reduced, the deposition effect can be ensured, the decomposition voltage of the material can be effectively reduced, and the stability and the cycle performance of the battery can be effectively improved.
It should be noted that, in the present embodiment, the lithium oxycarbide may beSelected as Li 2 C 2 O 4 、Li 2 C 4 O 4 And Li 2 CO 3 At least one of (a). The above-mentioned lithium oxycarbide reduces Li in the positive electrode active material during the formation process + The consumption of the electrolyte provides active lithium for the formation of a negative electrode SEI film, no by-product residue is generated after the active lithium is decomposed, the active lithium is stable in the air and easy to process, the positive electrode material is porous, the electrolyte can be favorably infiltrated, and the cycle performance and the rate capability of the battery can be effectively improved.
Correspondingly, the carbon source comprises at least one of ethanol, methanol, toluene, methane, ethylene and acetylene. The carbon source is coated on the surface of the lithium oxycarbide, so that the lithium oxycarbide can be effectively modified, the voltage window of the positive electrode lithium supplement agent is reduced, and the cycle performance and the stability of the battery are fully ensured. Meanwhile, the addition of the carbon source can reduce the use ratio of the conductive agent, so that the polarization can be reduced, the cycle performance of the battery is further improved, and the service life of the battery is prolonged.
Alternatively, in the embodiment of the present invention, the positive electrode lithium supplement precursor is prepared by the following steps: mixing lithium salt and an organic solvent to obtain a mixed solution, wherein the lithium salt is a lithium carbonate; and sanding and drying the mixed solution in sequence. The carbon-oxygen lithium compound with fine particles can be obtained through grinding and drying, so that the particle size of the positive electrode lithium supplement agent coated by the carbon source can be reduced, the lithium supplement effect can be ensured, and the cycle performance and the rate capability of the battery are improved.
In detail, the organic solvent includes at least one of ethanol, N-methylpyrrolidone, N-dimethylformamide, and tetrahydrofuran. The mass ratio of the lithium salt to the organic solvent is 1 (0.5-5), stirring is carried out in the mixing process, the stirring speed is 500-1500rmp, and the stirring can improve the uniformity of the solution. In the sanding step, the granularity D50 of the solution is less than 2 mu m, the sanding frequency is 500-1200Hz, the sanding time is 6-12h, and the size of the particles can be reduced by sanding. In the drying step, the drying mode is blast drying or spray drying, the drying temperature is 80-230 ℃, the drying time is 6-12h, the drying temperature is low, the stability of the carbon-oxygen lithium compound structure can be ensured, the lithium supplement effect can be ensured, the decomposition voltage of the material can be effectively reduced after the carbon source is deposited and coated, and the cycle performance and the stability of the battery can be ensured.
The embodiment of the invention also provides a positive pole piece, which comprises: a current collector and a positive electrode active material layer. Wherein, the current collector can be selected as an aluminum foil. The positive active material layer is obtained by coating the positive active slurry on at least one side of the current collector in the thickness direction and performing cold pressing and drying, and illustratively, the positive active material layer is arranged on both sides of the current collector. The coating manner includes any one of a continuous coating manner, a gap coating manner, or a dot coating manner. Illustratively, at least one of screen printing, gravure coating, extrusion coating, and transfer coating may be used.
And specifically, the positive electrode active paste includes a positive electrode active material, a conductive agent, a binder, a solvent, and the above-mentioned positive electrode lithium supplement agent. The positive electrode active material includes at least one of a nickel cobalt lithium manganate ternary material, a lithium iron phosphate material, a lithium manganate material, and a lithium cobaltate material, where the ternary material may be a general ternary material, or may be a coated, doped, or modified ternary material, and similarly, the lithium iron phosphate, the lithium manganate, and the lithium cobaltate material may also be a coated, doped, or modified material. The conductive agent includes at least one of conductive carbon black, conductive graphite, ketjen black, carbon fiber, carbon nanotube, graphene oxide, and vapor grown carbon fiber, and illustratively, embodiments of the present invention are selected to be conductive carbon black. The binder comprises at least one of polyvinylpyrrolidone, polyvinylidene fluoride, polyethylene oxide, polytetrafluoroethylene, sodium carboxymethylcellulose, styrene and butadiene copolymer. Illustratively, embodiments of the present invention are selected to be polyvinylidene fluoride. The solvent may be selected to be N-methylpyrrolidone (NMP).
The positive pole piece is prepared by the positive pole lithium supplement agent, so that the positive pole piece also has the effects of improving the cycle performance, stability and energy density of the battery.
Optionally, in the other components except the solvent of the positive electrode active slurry, the mass percentage of the positive electrode active material is 80-97%, the mass percentage of the positive electrode lithium supplement agent is 2-16%, and the total mass percentage of the conductive agent and the binder is 1-4%, for example, taking the mass percentage of the positive electrode active slurry as an example, the amount of the conductive agent can be selected to be 0.5-2%, and the amount of the binder can also be selected to be 0.5-2%. Through the arrangement of the anode lithium supplement agent, the using amount of the conductive agent in the anode active slurry is greatly reduced, and the cost can be saved. And through the arrangement of the positive electrode lithium supplement agent, the cycle performance and the stability of the battery can be ensured while the lithium is supplemented to improve the energy density of the battery.
In the above process, the preparation process of the positive electrode sheet specifically includes mixing the positive electrode active material, the positive electrode lithium supplement agent, the conductive agent and the binder according to the use ratio, then dispersing the mixture into the solvent, and uniformly mixing to obtain the positive electrode active slurry. And coating the positive active slurry on a current collector, and then carrying out cold pressing and drying to obtain the positive pole piece.
The embodiment of the invention also provides a battery which comprises a shell, a positive pole piece, an isolating membrane, a negative pole piece and electrolyte. The battery comprises a positive pole piece, an isolating membrane, a negative pole piece, a shell and an electrolyte, wherein the positive pole piece, the isolating membrane and the negative pole piece are stacked and arranged and then are laminated or wound to form a bare cell, the bare cell is then put into the shell, and the electrolyte is injected into the shell to obtain the battery. The battery can be a soft package battery, a square battery, a button battery or a cylindrical battery. The embodiment of the invention is illustrated by taking a pouch cell as an example, and in the process of preparing and forming the pouch cell, the shell is selected to be an aluminum plastic film. The battery is prepared by the positive pole piece. Therefore, the battery also has the advantages of high energy density, good cycle performance and high stability.
In detail, the negative electrode tab generally includes a current collector and a negative active material layer provided on at least one side surface of the current collector in a thickness direction. The negative active material layer is obtained by cold pressing and drying after negative active slurry is coated on a current collector. Among them, the negative electrode active slurry generally includes a negative electrode active material, a conductive agent, a binder, and a solvent. The negative active material can be at least one of artificial graphite, natural graphite, silicon simple substance Si, silicon oxide (SiOx, 0-less-x-less-2), tin simple substance Sn, lithium titanate and the like. The current collector may be, but is not limited to, a metal foil, and the like, and more particularly, may be, but is not limited to, a copper foil, and the like. The conductive agent can be selected from at least one of conductive carbon black, conductive graphite, ketjen black, carbon fiber, carbon nanotube, graphene oxide and vapor-grown carbon fiber, the binder can be selected from styrene butadiene rubber, and the solvent can be selected from deionized water or NPM. Sodium carboxymethyl cellulose (CMC) can also be added as a dispersant according to requirements. The separator may be any material suitable for use in lithium ion battery separators in the art, and may be a combination including, but not limited to, one or more of polyethylene, polypropylene, polyvinylidene fluoride, aramid, polyethylene terephthalate, polytetrafluoroethylene, polyacrylonitrile, polyimide, polyamide, polyester, natural fibers, and the like. The electrolyte can be selected from lithium hexafluorophosphate and other electrolytes.
As an optional scheme, in the negative active slurry, the usage ratio of the negative active material, the conductive agent and the binder can be selected to be 90-97%, 1-5% and 1-5%, and can be adjusted according to requirements.
The performance and beneficial effects of the battery prepared by the positive electrode lithium supplement agent are described in detail by specific examples, comparative examples and experimental examples as follows:
example 1
This example provides a battery prepared by:
s1: the preparation method of the positive electrode lithium supplement agent specifically comprises the following steps:
s11: lithium salt Li 2 C 2 O 4 Mixing the mixed solution with an organic solvent N-methyl pyrrolidone to obtain a mixed solution; the mass ratio of the lithium salt to the organic solvent is 1;
s12: sequentially grinding and drying the mixed solution to obtain a positive electrode lithium supplement agent precursor; in the sanding step, the granularity D50 of the solution is less than 2 mu m, the sanding frequency is 1000Hz, and the sanding time is 10h; in the drying step, the drying mode is blast drying or spray drying, the drying temperature is 200 ℃, and the drying time is 10 hours;
s13: placing a positive electrode lithium supplement agent precursor into a container, placing the container into chemical vapor deposition equipment with a cooling device, introducing ethanol into a reaction chamber of the chemical vapor deposition equipment, and allowing a carbon source in the reaction chamber to pass through a catalytic chamber so that the carbon material is deposited on the pretreated positive electrode lithium supplement agent to obtain the positive electrode lithium supplement agent; wherein the temperature of the cooling device is-25 ℃, the temperature of the catalytic chamber is 600 ℃, and the chemical vapor deposition time is 8h.
S2: the preparation method of the positive pole piece specifically comprises the following steps:
dispersing lithium iron phosphate, a positive electrode lithium supplement agent, a conductive agent and polyvinylidene fluoride into N-methylpyrrolidone (NMP) according to the mass ratio of 93.
S3: the preparation method of the battery specifically comprises the following steps:
and winding the positive pole piece, the negative pole piece and the isolating film to form a bare cell, putting the bare cell into an aluminum plastic film, and injecting electrolyte to obtain the lithium ion battery.
Example 2
The battery provided in this example is different from the battery provided in example 1 in the following preparation method:
in step S11, the lithium salt is Li 2 C 4 O 4 。
Example 3
The present example provides a battery, which is different from the preparation method of the battery provided in example 1 in that:
in step S11, the lithium salt is Li 2 CO 3 。
Example 4
The present example provides a battery, which is different from the preparation method of the battery provided in example 1 in that:
in step S13, the cooling temperature of the cooling device is-20 ℃, and the chemical vapor deposition time is 10h.
Example 5
The present example provides a battery, which is different from the preparation method of the battery provided in example 1 in that:
in step S13, the cooling temperature of the cooling device is-30 ℃, and the time of the chemical vapor deposition is 12h.
Example 6
The present example provides a battery, which is different from the preparation method of the battery provided in example 1 in that:
in step S13, the temperature of the catalytic chamber is 100 ℃, and the time of the chemical vapor deposition is 8h.
Example 7
The present example provides a battery, which is different from the preparation method of the battery provided in example 1 in that:
in step S13, the temperature of the catalytic chamber is 800 ℃, and the time of chemical vapor deposition is 8h.
Example 8
The present example provides a battery, which is different from the preparation method of the battery provided in example 1 in that:
in step S13, the temperature of the catalytic chamber is 400 ℃, and the time of chemical vapor deposition is 8h.
Example 9
The present example provides a battery, which is different from the preparation method of the battery provided in example 1 in that:
in step S13, the temperature of the catalytic chamber is 300 ℃, and the time of chemical vapor deposition is 12h.
Comparative example 1
The battery provided in comparative example 1 is different from the method for manufacturing the battery provided in example 1 in that:
without the modification process of step S1, in step S2, the positive electrode lithium supplement agent is selected to be Li 2 C 2 O 4 。
Comparative example 2
The battery provided in comparative example 2 is different from the method for manufacturing the battery provided in example 1 in that:
without the modification process of step S1, in step S2, the positive electrode lithium supplement agent is selected to be Li 2 C 4 O 4 。
Comparative example 3
The battery provided in comparative example 3 is different from the method for manufacturing the battery provided in example 1 in that:
without the modification process of step S1, in step S2, the positive electrode lithium supplement agent is selected to be Li 2 CO 3 。
Comparative example 4
The battery provided in comparative example 4 is different from the method for manufacturing the battery provided in example 1 in that:
the modification process of the step S1 is not carried out, and in the step S2, the positive electrode lithium supplement agent is not contained, and the content of the conductive agent is correspondingly increased.
Comparative example 5
The battery provided in comparative example 5 is different from the method for manufacturing the battery provided in example 1 in that:
in step S13, the cooling temperature of the cooling device is-40 ℃, and the chemical vapor deposition time is 12h.
Comparative example 6
The battery provided in comparative example 6 is different from the method for manufacturing the battery provided in example 1 in that:
in step S13, the cooling temperature of the cooling device is-10 ℃, and the chemical vapor deposition time is 6h.
Comparative example 7
The battery provided in comparative example 7 is different from the method for manufacturing the battery provided in example 1 in that:
in step S13, the temperature of the catalytic chamber is 100 ℃, and the chemical vapor deposition time is 15h.
Comparative example 8
The battery provided in comparative example 8 is different from the method for manufacturing the battery provided in example 1 in that:
in step S13, the temperature of the catalytic chamber is 1100 ℃, and the chemical vapor deposition time is 2h.
Comparative example 9
The battery provided in comparative example 9 is different from the method for manufacturing the battery provided in example 1 in that:
in step S13, the temperature of the catalytic chamber is 1200 ℃, and the chemical vapor deposition time is 2h.
Experimental example 1
For the decomposition potential test of the positive electrode lithium supplement agent of the batteries provided in examples 1 to 9 and comparative examples 1 to 9, dissolving the lithium supplement agent, the binder (PVDF) and the conductive agent (Super P) in a solvent (NMP) according to a mass ratio of 90; and (3) assembling the positive plate and the lithium plate into the power-on half cell, standing, and then carrying out CV test in a range of 2.7-4.8V at a sweep rate of 0.2mV/s, wherein the voltage corresponding to the strongest reaction peak of the lithium supplement agent is the decomposition potential, and the test results are shown in Table 1.
TABLE 1 decomposition potential test
As can be seen from comparison of data of examples 1 to 9 and comparative examples 1 to 9 in table 1, the modified positive electrode lithium supplement provided in the examples of the present invention can effectively reduce the decomposition potential of the material, so as to improve the cycle performance and stability of the battery. As can be seen from the comparison of the data of examples 1 to 3, the comparison of the data of comparative examples 1 to 3, and the comparison of examples 1 to 3 with comparative examples 1 to 3, the decomposition potential of the material modified with a carbon source at a low temperature is lower, and the cycle performance and stability of the battery can be more improved. Meanwhile, li 2 CO 3 Has a decomposition potential greater than Li 2 C 4 O 4 Decomposition potential of, li 2 C 4 O 4 Has a decomposition potential greater than Li 2 C 2 O 4 So that Li is preferably used 2 C 2 O 4 As lithium salt for preparing the lithium supplement agent of the positive electrode. As can be seen from the comparison of examples 1, 4 and 5, and comparative examples 5 and 6, when the cooling temperature of the cooling device is between-30 and-20 deg.C, especially between-30 and-25 deg.C, the decomposition potential of the material is more decreased, which is more advantageous for improving the stability and cycle performance of the battery, and when the cooling temperature of the cooling device is not between-30 and-20 deg.C, although it is also the caseThe decomposition potential of the material can be lowered to some extent, but the effect is inferior to that at a temperature between-30 and-20 ℃. From a comparison of examples 1, 7 to 9, and comparative examples 7 to 9, it can be seen that the decomposition potential of the material is more decreased when the catalytic temperature is between 300 ℃ and 1000 ℃, particularly between 400 ℃ and 900 ℃, which is more advantageous for improving the stability and cycle performance of the battery, and the effect of decreasing the decomposition potential of the material is not significant when the catalytic temperature is below 300 ℃ and above 1200 ℃, which is worse than that when the catalytic temperature is between 300 ℃ and 1000 ℃.
Experimental example 2
The batteries provided in examples 1 to 9 and comparative examples 1 to 9 were tested for capacity retention after 1000 cycles, cycle performance test: the formed battery cell is subjected to primary charging and discharging after discharging in an environment of 25 ℃, the battery cell is subjected to constant current charging to a voltage of 3.65V under a charging current of 1C, then the charging cutoff current is 0.05C under a constant voltage of 3.65V, standing is carried out for 15min, constant current discharging is carried out to 2.0V under a discharging current of 1C, and the discharging capacity of the first circulation is recorded as C1; then, 1000 cycles of charge and discharge were performed, and the discharge capacity C1000 at the 1000 th cycle was recorded, and the C1000/C1 × 100% was recorded as the discharge capacity retention rate at 1000 cycles of the cell, and the test results are shown in table 2.
TABLE 2 capacity retention after 1000 cycles
As can be seen from the comparison of the data of examples 1 to 9 and comparative examples 1 to 9 in Table 1, the modified positive electrode lithium supplement agent provided by the examples of the present invention can effectively improve the cycle performance and stability of the battery. As can be seen from the comparison of the data of examples 1 to 3 with those of comparative examples 1 to 3 and the comparison of examples 1 to 3 with those of comparative examples 1 to 3, the material modified with a carbon source at a low temperature has a lower decomposition potential and is more likely to have a lower decomposition potentialThe cycle performance and stability of the battery are improved. Meanwhile, li 2 CO 3 Has a decomposition potential greater than Li 2 C 4 O 4 Decomposition potential of, li 2 C 4 O 4 Has a decomposition potential greater than Li 2 C 2 O 4 So that Li is preferably used 2 C 2 O 4 As lithium salt for preparing the positive electrode lithium supplement agent. As can be seen from the comparison of examples 1, 4 and 5, and comparative examples 5 and 6, when the cooling temperature of the cooling device is between-30 and-20 c, particularly between-30 and-25 c, it is more advantageous to improve the stability and cycle performance of the battery, and when the cooling temperature of the cooling device is not between-30 and-20 c, although the cycle performance can be improved to some extent, the effect is inferior to that at between-30 and-20 c. It is understood from the comparison of examples 1, 7 to 9, and comparative examples 7 to 9 that the improvement of the cycle performance is not significant when the catalytic temperature is lower than 300 ℃ and higher than 1200 ℃ and is inferior to that in the case of 300 ℃ to 1000 ℃ in the improvement of the stability and cycle performance of the battery when the catalytic temperature is 300 ℃ to 1000 ℃, particularly 400 ℃ to 900 ℃.
In summary, in the embodiments of the present invention, the carbon source is used to modify the precursor of the positive electrode lithium supplement agent, which not only provides a lithium supplement effect and ensures the energy density of the battery, but also effectively reduces the voltage window of the positive electrode lithium supplement agent to reduce the decomposition voltage of the material, thereby improving the stability and cycle performance of the battery; on the other hand, the embodiment of the invention is modified in a low-temperature chemical vapor deposition mode, the low-temperature chemical vapor deposition is matched with the lithium oxycarbide with a low melting point, the melting or chemical change of the material caused by high-temperature treatment is avoided, and the uniform and stable coating of the carbon source on the surface of the lithium oxycarbide can be ensured, so that the decomposition voltage of the material can be further reduced, and the stability and the cycle performance of the battery can be ensured.
In summary, the cathode lithium supplement agent with low decomposition voltage and the preparation method thereof provided by the embodiments of the present invention can provide a lithium supplement effect, ensure the energy density of the battery, and effectively improve the stability and cycle performance of the battery. The positive pole piece and the battery provided by the embodiment of the invention comprise the positive pole lithium supplement agent. Therefore, it also has advantages of high energy density, high stability and high cycle performance.
The present invention has been described in terms of the preferred embodiment, and it is not intended to be limited to the embodiment. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A preparation method of a positive electrode lithium supplement agent is characterized by comprising the following steps:
depositing a carbon source on the surface of the positive electrode lithium supplement precursor in a low-temperature vapor deposition mode; wherein the positive electrode lithium supplement precursor comprises a lithium oxycarbide.
2. The method for preparing a positive electrode lithium supplement agent according to claim 1, characterized in that:
the low-temperature vapor deposition is carried out in a reaction chamber of chemical vapor deposition equipment with a cooling device, and the carbon source forms a nano carbon material after passing through a catalytic chamber in the reaction chamber and is deposited on the surface of the positive electrode lithium supplement precursor;
wherein the temperature of the cooling device is-30 to-20 ℃, the temperature of the catalytic chamber is 300 to 1000 ℃, and the chemical vapor deposition time is 0.5 to 12 hours.
3. The method for preparing a positive electrode lithium supplement agent according to claim 2, characterized in that:
the temperature of the cooling device is-30 to-25 ℃, the temperature of the catalytic chamber is 400 to 900 ℃, and the chemical vapor deposition time is 4 to 8 hours.
4. The method for preparing a positive electrode lithium supplement agent according to claim 1, characterized in that:
the lithium oxycarbide includes Li 2 C 2 O 4 、Li 2 C 4 O 4 And Li 2 CO 3 At least one of (a);
and/or the presence of a gas in the gas,
the carbon source includes at least one of ethanol, methanol, toluene, methane, ethylene, and acetylene.
5. The method for preparing the positive lithium supplement agent according to claim 1, wherein the positive lithium supplement agent precursor is prepared by the following steps:
mixing a lithium salt and an organic solvent to obtain a mixed solution, wherein the lithium salt is a lithium carbonate oxide;
and sanding and drying the mixed solution in sequence.
6. The method for preparing the positive electrode lithium supplement agent according to claim 5, wherein:
the organic solvent comprises at least one of ethanol, N-methyl pyrrolidone, N-dimethylformamide and tetrahydrofuran;
and/or the mass ratio of the lithium salt to the organic solvent is 1 (0.5-5), stirring is carried out during the mixing process, and the stirring speed is 500-1500rmp;
and/or in the sanding step, the granularity D50 of the solution is less than 2 mu m, the sanding frequency is 500-1200Hz, and the sanding time is 6-12h;
and/or in the drying step, the drying mode is air blast drying or spray drying, the drying temperature is 80-230 ℃, and the drying time is 6-12h.
7. A positive electrode lithium supplementing agent, which is prepared by the method for preparing a positive electrode lithium supplementing agent according to any one of claims 1 to 6.
8. A positive electrode sheet, comprising:
a current collector;
the positive electrode active material layer is obtained by coating positive electrode active slurry on at least one side of the current collector in the thickness direction and performing cold pressing and drying, and the positive electrode active slurry comprises a positive electrode active material, a conductive agent, a binder, a solvent, and the positive electrode lithium supplement agent prepared by the preparation method of the positive electrode lithium supplement agent according to any one of claims 1 to 6, or the positive electrode lithium supplement agent according to claim 7.
9. The positive electrode sheet according to claim 8, wherein:
in the other components of the positive electrode active slurry except the solvent, the mass percentage of the positive electrode active substance is 80-97%, the mass percentage of the positive electrode lithium supplement agent is 2-16%, and the total mass percentage of the conductive agent and the binder is 1-4%;
and/or the positive active substance comprises at least one of a nickel cobalt lithium manganate ternary material, a lithium iron phosphate material, a lithium manganate material and a lithium cobaltate material;
and/or the conductive agent comprises at least one of conductive carbon black, conductive graphite, ketjen black, carbon fiber, carbon nanotube, graphene oxide and vapor grown carbon fiber;
and/or the binder comprises at least one of polyvinylpyrrolidone, polyvinylidene fluoride, polyethylene oxide, polytetrafluoroethylene, sodium carboxymethylcellulose, styrene and further a copolymer of butadiene;
and/or the coating mode comprises any one of continuous coating, gap coating or point coating mode.
10. A battery comprising the positive electrode sheet claimed in claim 9.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107068972A (en) * | 2017-03-22 | 2017-08-18 | 江苏元景锂粉工业有限公司 | The ternary material anode pole piece and its lithium ion battery of a kind of quick charge |
| CN111834618A (en) * | 2020-06-12 | 2020-10-27 | 松山湖材料实验室 | Carbon-coated lithium supplement material and preparation method and application thereof |
| US20200411851A1 (en) * | 2019-06-27 | 2020-12-31 | Graphenix Development, Inc. | Patterned anodes for lithium-based energy storage devices |
| CN114464909A (en) * | 2022-04-14 | 2022-05-10 | 华中科技大学 | Nano composite anode lithium supplement slurry and anode |
| CN114927778A (en) * | 2022-06-09 | 2022-08-19 | 蜂巢能源科技股份有限公司 | Positive electrode lithium supplement additive and preparation method and application thereof |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107068972A (en) * | 2017-03-22 | 2017-08-18 | 江苏元景锂粉工业有限公司 | The ternary material anode pole piece and its lithium ion battery of a kind of quick charge |
| US20200411851A1 (en) * | 2019-06-27 | 2020-12-31 | Graphenix Development, Inc. | Patterned anodes for lithium-based energy storage devices |
| CN111834618A (en) * | 2020-06-12 | 2020-10-27 | 松山湖材料实验室 | Carbon-coated lithium supplement material and preparation method and application thereof |
| CN114464909A (en) * | 2022-04-14 | 2022-05-10 | 华中科技大学 | Nano composite anode lithium supplement slurry and anode |
| CN114927778A (en) * | 2022-06-09 | 2022-08-19 | 蜂巢能源科技股份有限公司 | Positive electrode lithium supplement additive and preparation method and application thereof |
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