CN117013076A - Lithium ion electrolyte and lithium ion battery - Google Patents
Lithium ion electrolyte and lithium ion battery Download PDFInfo
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- CN117013076A CN117013076A CN202311061129.9A CN202311061129A CN117013076A CN 117013076 A CN117013076 A CN 117013076A CN 202311061129 A CN202311061129 A CN 202311061129A CN 117013076 A CN117013076 A CN 117013076A
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- ion battery
- lithium ion
- lithium
- compound
- battery electrolyte
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- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 72
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 72
- 239000003792 electrolyte Substances 0.000 title claims abstract description 54
- 150000001875 compounds Chemical class 0.000 claims abstract description 55
- 239000000654 additive Substances 0.000 claims abstract description 23
- 229940126062 Compound A Drugs 0.000 claims abstract description 22
- 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 claims abstract description 22
- 230000000996 additive effect Effects 0.000 claims abstract description 22
- 229910003002 lithium salt Inorganic materials 0.000 claims abstract description 14
- 159000000002 lithium salts Chemical class 0.000 claims abstract description 14
- 239000002904 solvent Substances 0.000 claims abstract description 13
- 239000003607 modifier Substances 0.000 claims abstract description 9
- 229910052744 lithium Inorganic materials 0.000 claims description 19
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 16
- BTBUEUYNUDRHOZ-UHFFFAOYSA-N Borate Chemical compound [O-]B([O-])[O-] BTBUEUYNUDRHOZ-UHFFFAOYSA-N 0.000 claims description 14
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 claims description 14
- -1 lithium hexafluorophosphate Chemical compound 0.000 claims description 14
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 claims description 12
- 229910052736 halogen Inorganic materials 0.000 claims description 12
- 150000002367 halogens Chemical class 0.000 claims description 12
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 claims description 10
- 229910052739 hydrogen Inorganic materials 0.000 claims description 8
- 125000000217 alkyl group Chemical group 0.000 claims description 7
- 239000001257 hydrogen Substances 0.000 claims description 7
- 150000002431 hydrogen Chemical class 0.000 claims description 6
- 239000003960 organic solvent Substances 0.000 claims description 6
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims description 5
- 229910019142 PO4 Inorganic materials 0.000 claims description 5
- 239000002253 acid Substances 0.000 claims description 5
- 125000003342 alkenyl group Chemical group 0.000 claims description 5
- 150000007513 acids Chemical class 0.000 claims description 4
- 229910001496 lithium tetrafluoroborate Inorganic materials 0.000 claims description 4
- VDVLPSWVDYJFRW-UHFFFAOYSA-N lithium;bis(fluorosulfonyl)azanide Chemical compound [Li+].FS(=O)(=O)[N-]S(F)(=O)=O VDVLPSWVDYJFRW-UHFFFAOYSA-N 0.000 claims description 4
- 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 claims description 4
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims description 4
- 239000010452 phosphate Substances 0.000 claims description 4
- 125000003277 amino group Chemical group 0.000 claims description 3
- 150000004649 carbonic acid derivatives Chemical class 0.000 claims description 3
- UQSQSQZYBQSBJZ-UHFFFAOYSA-M fluorosulfate group Chemical group S(=O)(=O)([O-])F UQSQSQZYBQSBJZ-UHFFFAOYSA-M 0.000 claims description 3
- 125000002924 primary amino group Chemical group [H]N([H])* 0.000 claims description 3
- 150000004756 silanes Chemical class 0.000 claims description 3
- 150000003467 sulfuric acid derivatives Chemical class 0.000 claims description 3
- 235000010338 boric acid Nutrition 0.000 claims description 2
- 125000005619 boric acid group Chemical class 0.000 claims description 2
- 235000011007 phosphoric acid Nutrition 0.000 claims description 2
- 150000003016 phosphoric acids Chemical class 0.000 claims description 2
- 125000003808 silyl group Chemical group [H][Si]([H])([H])[*] 0.000 claims description 2
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 claims description 2
- 125000002947 alkylene group Chemical group 0.000 claims 1
- DWYMPOCYEZONEA-UHFFFAOYSA-L fluoridophosphate Chemical compound [O-]P([O-])(F)=O DWYMPOCYEZONEA-UHFFFAOYSA-L 0.000 claims 1
- 230000014759 maintenance of location Effects 0.000 abstract description 9
- 239000007772 electrode material Substances 0.000 abstract description 8
- 239000010405 anode material Substances 0.000 abstract description 2
- 239000010406 cathode material Substances 0.000 abstract description 2
- 238000007086 side reaction Methods 0.000 abstract description 2
- 230000002195 synergetic effect Effects 0.000 abstract description 2
- VAYTZRYEBVHVLE-UHFFFAOYSA-N 1,3-dioxol-2-one Chemical compound O=C1OC=CO1 VAYTZRYEBVHVLE-UHFFFAOYSA-N 0.000 description 9
- 230000000052 comparative effect Effects 0.000 description 8
- 238000012360 testing method Methods 0.000 description 8
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 7
- 239000011267 electrode slurry Substances 0.000 description 7
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 description 7
- FSSPGSAQUIYDCN-UHFFFAOYSA-N 1,3-Propane sultone Chemical compound O=S1(=O)CCCO1 FSSPGSAQUIYDCN-UHFFFAOYSA-N 0.000 description 5
- SBLRHMKNNHXPHG-UHFFFAOYSA-N 4-fluoro-1,3-dioxolan-2-one Chemical compound FC1COC(=O)O1 SBLRHMKNNHXPHG-UHFFFAOYSA-N 0.000 description 5
- 238000002156 mixing Methods 0.000 description 5
- ZPFAVCIQZKRBGF-UHFFFAOYSA-N 1,3,2-dioxathiolane 2,2-dioxide Chemical compound O=S1(=O)OCCO1 ZPFAVCIQZKRBGF-UHFFFAOYSA-N 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 4
- 238000000576 coating method Methods 0.000 description 4
- 238000001035 drying Methods 0.000 description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 235000021317 phosphate Nutrition 0.000 description 4
- 150000002500 ions Chemical class 0.000 description 3
- IGILRSKEFZLPKG-UHFFFAOYSA-M lithium;difluorophosphinate Chemical compound [Li+].[O-]P(F)(F)=O IGILRSKEFZLPKG-UHFFFAOYSA-M 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- ZRZFJYHYRSRUQV-UHFFFAOYSA-N phosphoric acid trimethylsilane Chemical compound C[SiH](C)C.C[SiH](C)C.C[SiH](C)C.OP(O)(O)=O ZRZFJYHYRSRUQV-UHFFFAOYSA-N 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 239000006245 Carbon black Super-P Substances 0.000 description 2
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 2
- HFCVPDYCRZVZDF-UHFFFAOYSA-N [Li+].[Co+2].[Ni+2].[O-][Mn]([O-])(=O)=O Chemical compound [Li+].[Co+2].[Ni+2].[O-][Mn]([O-])(=O)=O HFCVPDYCRZVZDF-UHFFFAOYSA-N 0.000 description 2
- 239000011149 active material Substances 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 239000006258 conductive agent Substances 0.000 description 2
- 239000011889 copper foil Substances 0.000 description 2
- 125000000113 cyclohexyl group Chemical group [H]C1([H])C([H])([H])C([H])([H])C([H])(*)C([H])([H])C1([H])[H] 0.000 description 2
- 239000011888 foil Substances 0.000 description 2
- 238000004806 packaging method and process Methods 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- 239000007784 solid electrolyte Substances 0.000 description 2
- 229920003048 styrene butadiene rubber Polymers 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910001428 transition metal ion Inorganic materials 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- XVMSFILGAMDHEY-UHFFFAOYSA-N 6-(4-aminophenyl)sulfonylpyridin-3-amine Chemical compound C1=CC(N)=CC=C1S(=O)(=O)C1=CC=C(N)C=N1 XVMSFILGAMDHEY-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910013872 LiPF Inorganic materials 0.000 description 1
- 101150058243 Lipf gene Proteins 0.000 description 1
- 239000002033 PVDF binder Substances 0.000 description 1
- JUJWROOIHBZHMG-UHFFFAOYSA-N Pyridine Chemical group C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 description 1
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical group [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 150000001450 anions Chemical class 0.000 description 1
- 239000011884 anode binding agent Substances 0.000 description 1
- 239000006256 anode slurry Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 150000001642 boronic acid derivatives Chemical class 0.000 description 1
- 239000001768 carboxy methyl cellulose Substances 0.000 description 1
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 1
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 239000011883 electrode binding agent Substances 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000007773 negative electrode material Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 238000002161 passivation Methods 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 230000005501 phase interface Effects 0.000 description 1
- 150000003013 phosphoric acid derivatives Chemical class 0.000 description 1
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 1
- 239000007774 positive electrode material Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 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
- 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
- H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
- H01M10/0566—Liquid materials
- H01M10/0567—Liquid materials characterised by the additives
-
- 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
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
- H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M2300/00—Electrolytes
- H01M2300/0088—Composites
- H01M2300/0091—Composites in the form of mixtures
-
- 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)
- Manufacturing & Machinery (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Inorganic Chemistry (AREA)
- Materials Engineering (AREA)
- Secondary Cells (AREA)
Abstract
The application provides a lithium ion electrolyte and a lithium ion battery, which belong to the technical field of battery electrolytes, wherein the lithium ion battery electrolyte comprises lithium salt, a solvent, a film forming additive and a film forming modifier, the film forming modifier comprises a compound A shown in a formula 1 and a compound B shown in a formula 2, and the synergistic effect of the compound A and the compound B can form a stable, compact and small-impedance SEI film on a battery anode and cathode material with the film forming additive, so that the structural stability of the anode and cathode electrode material is improved, the electrolyte is relatively stable in a high-temperature environment, the side reaction is less, the interface stability in the high-temperature environment above 60 ℃ is effectively improved, and the cycle stability and the storage stability are improved. The lithium ion battery obtained by using the lithium ion battery electrolyte provided by the application has the storage capacity retention rate of 80.12% -98.98% in 28 days of storage at 70 ℃ and the cycle capacity retention rate of 79.1% -98.8% at 60 ℃.
Description
Technical Field
The application belongs to the technical field of battery electrolyte, and particularly relates to lithium ion battery electrolyte and a lithium ion battery.
Background
The high-capacity lithium ion battery has the characteristics of large capacity, high specific energy, long cycle life, no environmental pollution and the like, and has great application prospect in the fields of civil power supplies such as mobile phones, notebook computers and the like, vehicle-mounted power supplies for driving automobiles and the like, so that the high-capacity lithium ion battery draws attention of a plurality of scientists.
Along with the wider application of the lithium ion battery, the performance requirement on the lithium ion battery is higher and higher, and particularly, the military lithium ion battery is required to meet the working index requirement of the high-temperature environment above 60 ℃ while meeting the working of the normal-temperature environment. The output performance of a general lithium ion battery is rapidly deteriorated at 60 ℃.
From the influence factors of the lithium ion battery, starting from the electrolyte, improving the high-temperature performance of the battery by optimizing the composition of the electrolyte is the most economical means. Therefore, developing an electrolyte with high stability, high efficiency and excellent electrochemical performance, which is applied to a lithium ion battery to improve the high temperature performance of the battery, is an urgent problem in the art.
Disclosure of Invention
Aiming at the defects of the prior art, the application aims to provide lithium ion battery electrolyte with excellent high-temperature performance and a lithium ion battery.
One of the purposes of the application is to provide a lithium ion battery electrolyte, which comprises lithium salt, a solvent, a film forming additive and a film forming modifier;
the film forming modifier comprises a compound A shown in a formula 1 and a compound B shown in a formula 2.
Wherein R is 1 Is hydrogen, C 3 ~C 6 Silane group, halogen, optionally substituted amino group, optionally substituted C 1 ~C 7 Alkyl or optionally substitutedC of (2) 3 ~C 9 Any one of the alkenyl groups of (2).
R 2 And R is 3 Each independently selected from hydrogen, C 3 ~C 6 Silane groups, halogen, optionally substituted C 1 ~C 7 Or optionally substituted C 3 ~C 9 Any one of the alkenyl groups of (2).
Preferably, the mass percentage of the compound A in the lithium ion battery electrolyte is 0.1-3%.
Preferably, the mass percentage of the compound B in the lithium ion battery electrolyte is 0.1-3%.
Preferably, the molar ratio of the compound A to the compound B is 1.5-2.5:1, preferably 2:1.
Preferably, said R 1 Comprising halogen, unsubstituted C 1 ~C 3 C substituted by alkyl, halogen 1 ~C 3 Alkyl or C of (2) 3 ~C 6 Preferably comprising-H, -F, -CH 3 、-CH 2 CH 3 、-CH 2 CH 2 CH 3 、-CF 3 -ch=ch2 or-CH 2 CH=CH 2 Any one of them;
preferably, said R 2 And R is 3 Each independently comprises unsubstituted C 1 ~C 6 C substituted by alkyl, amino 1 ~C 6 Alkyl or silyl groups of (C), preferably including-CH 3 、-CH 2 CH 3 、-CH(CH 3 ) 2 、-CH(CH 3 ) 3 Cyclohexyl or-CH 2 CH 2 CH 2 N(CH 3 ) 3 Any one of the following.
Preferably, the structure of the compound a includes one or more of the compounds described by the following formula.
Preferably, the compound B comprises one or more of the compounds described below;
preferably, the film forming additive comprises one or more of carbonates, sulfates, phosphoric acids, boric acids, silanes, fluorocarbons, fluorosulfates, fluorophosphoric acids, fluoroboric acids or fluorosilanes.
Preferably, the film-forming additive comprises one or more of vinylene carbonate, 1, 3-propane sultone, fluoroethylene carbonate, tris (trimethylsilane) phosphate or ethylene sulfate.
Preferably, the mass percentage of the film forming additive in the lithium ion battery electrolyte is 0.05-5%.
Preferably, the solvent comprises a carbonate-based organic solvent.
In the application, the total weight of the lithium ion battery electrolyte is taken as 100 percent, and the balance is solvent except lithium salt, film forming additive, compound A and compound B.
Preferably, the carbonate-based organic solvent comprises any one or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate or methyl ethyl carbonate.
Preferably, the solvent comprises ethylene carbonate, diethyl carbonate and ethylmethyl carbonate.
Preferably, the mass ratio of ethylene carbonate, diethyl carbonate and ethylmethyl carbonate is 3:2:5.
Preferably, the lithium salt comprises one or more of lithium hexafluorophosphate, lithium bisoxalato borate, lithium difluorooxalato borate, lithium bis- (trifluoromethylsulfonyl) imide, lithium bis (fluorosulfonyl) imide, lithium difluorophosphate, lithium tetrafluoroborate or lithium difluorobisoxalato phosphate.
Preferably, the mass percentage of the lithium salt in the lithium ion battery electrolyte is 7.5% -18.5%.
Another object of the present application is to provide a lithium ion battery comprising the lithium ion battery electrolyte as described above.
The beneficial effects of the application include:
according to the application, the compound A and the compound B are added to serve as film forming modifiers, and the synergistic effect of the compound A and the compound B and the film forming additives can form a stable, compact and small-impedance SEI film on the anode and cathode materials of the battery, so that the structural stability of the anode and cathode electrode materials is improved, the electrolyte is relatively stable in a high-temperature environment, and side reactions are less, so that the interface stability in the high-temperature environment above 60 ℃ is effectively improved, and the cycle stability and the storage stability are improved. The lithium ion battery obtained by using the lithium ion battery electrolyte provided by the application has the storage capacity retention rate of 80.12% -98.98% in 28 days of storage at 70 ℃ and the cycle capacity retention rate of 79.1% -98.8% at 60 ℃.
Detailed Description
In the following description, certain specific details are included to provide a thorough understanding of various disclosed embodiments. One skilled in the relevant art will recognize, however, that the embodiments may be practiced without one or more of the specific details, or with other methods, components, materials, etc.
Unless otherwise required by the present application, the words "comprise" and "comprising" are to be interpreted in an open, inclusive sense, i.e. "including but not limited to.
Reference throughout this specification to "one embodiment" or "an embodiment" or "one preferred embodiment" or "certain embodiments" means that a particular reference element, structure, or feature described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrase "in one embodiment" or "in an embodiment" or "in a preferred embodiment" or "in certain embodiments" appearing in various places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular elements, structures, or features may be combined in any suitable manner in one or more embodiments.
According to a first aspect of the present application, there is provided a lithium ion battery electrolyte comprising a lithium salt, a solvent, a film forming additive and a film forming modifier;
the film forming modifier comprises a compound A shown in a formula 1 and a compound B shown in a formula 2.
Wherein R is 1 Is hydrogen, C 3 ~C 6 Silane group, halogen, optionally substituted amino group, optionally substituted C 1 ~C 7 Or optionally substituted C 3 ~C 9 Any one of the alkenyl groups of (2).
R 2 And R is 3 Each independently selected from hydrogen, C 3 ~C 6 Silane groups, halogen, optionally substituted C 1 ~C 7 Or optionally substituted C 3 ~C 9 Any one of the alkenyl groups of (2).
In the present application, the film-forming additive means an additive for forming a solid electrolyte interface film (solid electrolyte interface), abbreviated as SEI film. In the first charge and discharge process of the lithium ion battery, the film forming additive reacts on the solid-liquid phase interface of the electrode material and the electrolyte to form a passivation film, namely an SEI film, which covers the surface of the electrode material. SEI films are electron insulators, also Li + Excellent conductor of Li + Can be freely inserted and extracted through the SEI film. The SEI film has a protective effect on the electrode material, so that the material structure is not easy to collapse, and the cycle life of the electrode material is prolonged.
In the present application, the compound B can react with water and active hydrogen to be used as an additive for removing acid and water. On the other hand, the compound B can be mutually cooperated with the compound A, and forms an SEI film rich in S and N on the electrode together with a film forming additive, so that the interface stability in a high-temperature environment above 60 ℃ can be effectively improved, and the cycle stability and the storage stability are improved. Pyridine in the compound A can be complexed with transition metal ions dissolved out from the positive electrode, so that the transition metal ions are prevented from migrating to damage an SEI film, the loss of electrolyte caused by the reconstruction of the SEI film is reduced, and the storage stability and the cycle life are improved. N on pyridine ring in the compound A can capture O ions decomposed from positive electrode or electrolyte, prevent the O ions from further reacting with electrolyte components, improve the stability of the electrolyte and improve the high-temperature storage performance.
Preferably, said R 1 Comprising halogen, unsubstituted C 1 ~C 3 C substituted by alkyl, halogen 1 ~C 3 Alkyl or C of (2) 3 ~C 6 Any one of the vinyl groups of (C), R 1 For example, -H, -F, -CH 3 、-CH 2 CH 3 、-CH 2 CH 2 CH 3 、-CF 3 、-CH=CH 2 or-CH 2 CH=CH 2 。
Preferably, said R 2 And R is 3 Each independently comprises unsubstituted C 1 ~C 6 C substituted by alkyl, amino 1 ~C 6 Alkyl or silyl radicals of (E) are, for example, -CH 3 、-CH 2 CH 3 、-CH(CH 3 ) 2 、-CH(CH 3 ) 3 Cyclohexyl or-CH 2 CH 2 CH 2 N(CH 3 ) 3 。
In a preferred embodiment of the application, the mass percentage of the compound A in the lithium ion battery electrolyte is 0.1-3%, and the mass percentage of the compound B in the lithium ion battery electrolyte is 0.1-3%.
In the application, if the addition amount of the compound A and the compound B is too small, when the compound A and the compound B are applied to a lithium ion battery, an SEI film which is stable enough cannot be formed on the surface of an electrode material, the structural stability of the positive and negative electrode materials is insufficient, and the final cycle performance of the battery is poor; if the addition amount of the compound A and the compound B is too high, an SEI film formed on the surface of the electrode material is thicker, so that on one hand, the transmission of lithium ions is influenced, on the other hand, excessive lithium ions are consumed, the coulomb efficiency of the lithium ion battery is influenced, and the cycle life is reduced.
In the present application, the mass percentage of the compound a is 0.1 to 3%, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8% or 3%, and specific point values between the above point values, are limited to the space and for brevity, the present application does not exhaustively list specific point values included in the range.
In the present application, the mass percentage of the compound B is 0.1 to 3%, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8% or 3%, and specific point values between the above point values, are limited to the space and for brevity, the present application does not exhaustively list specific point values included in the range.
In a preferred embodiment of the present application, the molar ratio of the compound a to the compound B is 1.5 to 2.5:1, for example 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1 or 2.5:1, preferably 2:1.
In a preferred embodiment of the present application, the structure of compound a comprises one or more of the compounds described by the following formula;
in a preferred embodiment of the present application, the compound B comprises one or several of the compounds described below;
in a preferred embodiment of the present application, the structure of the compound A is shown in formula 1-2, and the structure of the compound B is shown in formula 2-1;
。
in the present application, F enhances the chemical stability of pyridineThe high voltage resistance of the electrolyte is improved to a certain extent. Silicon-based is an anion acceptor, and PF 6 - Or F - Bonding can improve Li ＋ Mobility, and simultaneously, the silane groups can modify the SEI film of the electrode to improve ion conductivity and reduce impedance.
In a preferred embodiment of the present application, the film forming additive comprises one or more of carbonates, sulfates, phosphates, borates, silanes, fluorocarbons, fluorosulfates, fluorophosphates, fluoroborates, or fluorosilanes.
Preferably, the film-forming additive comprises one or more of vinylene carbonate, 1, 3-propane sultone, fluoroethylene carbonate, tris (trimethylsilane) phosphate or ethylene sulfate.
In the present application, the film-forming additive is, for example, vinylene carbonate, 1, 3-propane sultone, fluoroethylene carbonate, tris (trimethylsilane) phosphate, ethylene sulfate, vinylene carbonate and 1, 3-propane sultone, vinylene carbonate and fluoroethylene carbonate, vinylene carbonate and ethylene sulfate, or a combination of vinylene carbonate, 1, 3-propane sultone and fluoroethylene carbonate.
Preferably, the mass percentage of the film forming additive in the lithium ion battery electrolyte is 0.05-5%, for example, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8%, 3%, 3.2%, 3.4%, 3.6%, 3.8%, 4%, 4.2%, 4.4%, 4.6% or 4.8%.
In a preferred embodiment of the present application, the solvent comprises a carbonate-based organic solvent.
Preferably, the carbonate-based organic solvent comprises any one or more of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate or methyl ethyl carbonate.
In the present application, the organic solvent is, for example, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methylethyl carbonate, ethylene carbonate and propylene carbonate, ethylene carbonate and dimethyl carbonate, propylene carbonate and dimethyl carbonate, ethylene carbonate, propylene carbonate and dimethyl carbonate, or a combination of propylene carbonate, dimethyl carbonate and diethyl carbonate.
In a preferred embodiment of the present application, the solvent comprises ethylene carbonate, diethyl carbonate and ethylmethyl carbonate.
Preferably, the mass ratio of ethylene carbonate, diethyl carbonate and ethylmethyl carbonate is 3:2:5.
In a preferred embodiment of the present application, the lithium salt includes one or more of lithium hexafluorophosphate, lithium bis (oxalato) borate, lithium difluorooxalato borate, lithium bis (trifluoromethylsulfonyl) imide, lithium bis (fluorosulfonyl) imide, lithium difluorophosphate, lithium tetrafluoroborate, or lithium difluorobis (oxalato) phosphate.
In the present application, the lithium salt is, for example, lithium hexafluorophosphate, lithium bis (oxalato) borate, lithium difluorooxalato borate, lithium bis- (trifluoromethylsulfonyl) imide, lithium bis (fluorosulfonyl) imide, lithium difluorophosphate, lithium tetrafluoroborate or lithium difluorobis (oxalato) phosphate, lithium hexafluorophosphate and lithium bis (oxalato) borate, lithium hexafluorophosphate and lithium difluorooxalato borate, lithium bis (oxalato) borate and lithium difluorooxalato borate, or a combination of lithium hexafluorophosphate, lithium bis (oxalato) borate and lithium difluorooxalato borate.
Preferably, the mass percentage of the lithium salt in the lithium ion battery electrolyte is 7.5% -18.5%, for example 7.6%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, 15%, 15.5%, 16%, 16.5%, 17%, 17.5%, 18% or 18.4%.
In a preferred embodiment of the application, the preparation method of the lithium ion battery electrolyte comprises the steps of adding a lithium salt into a solvent for dissolution, adding a film forming additive, a compound A and a compound B, and uniformly mixing.
According to another aspect of the present application, there is provided a lithium ion battery comprising a lithium ion battery electrolyte as described above.
In a preferred embodiment of the present application, the lithium ion battery includes a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and an electrolyte as described above.
Preferably, the positive electrode and the negative electrode include an active material, a conductive agent, a current collector, and a binder binding the active material with the conductive agent and the current collector.
Specifically, the preparation method of the lithium ion battery comprises the following steps:
mixing nickel cobalt lithium manganate, an anode binder, carbon and conductive carbon black to prepare anode slurry;
mixing carbon, conductive carbon black, carboxymethyl cellulose and styrene-butadiene rubber to prepare negative electrode slurry;
then, coating positive electrode slurry on an aluminum foil current collector, coating negative electrode slurry on the copper foil current collector, and drying to obtain a positive electrode plate and a negative electrode plate;
and packaging the positive pole piece, the negative pole piece and the polyethylene diaphragm, drying, injecting electrolyte, and forming to obtain the lithium ion battery.
Examples
In the following description, certain specific details are included to provide a thorough understanding of various disclosed embodiments. One skilled in the relevant art will recognize, however, that the embodiments may be practiced without one or more of the specific details, or with other methods, components, materials, etc.
Unless otherwise required by the present application, the words "comprise" and "comprising" are to be interpreted in an open, inclusive sense, i.e. "including but not limited to.
Reference throughout this specification to "one embodiment" or "an embodiment" or "one preferred embodiment" or "certain embodiments" means that a particular reference element, structure, or feature described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrase "in one embodiment" or "in an embodiment" or "in a preferred embodiment" or "in certain embodiments" appearing in various places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular elements, structures, or features may be combined in any suitable manner in one or more embodiments.
Raw materials
Solvent: ethylene Carbonate (EC), diethyl carbonate (DEC) and methyl ethyl carbonate (EMC) in a mass ratio of 3:2:5;
lithium salt: lithium hexafluorophosphate (LiPF) 6 ）；
Film-forming additive: vinylene Carbonate (VC);
regarding compound a and compound B:
example 1 using compound a shown as formula 1-1 and compound B shown as formula 2-3;
examples 2 and 7 to 13 use a compound A represented by the formula 1-2 and a compound B represented by the formula 2-1;
example 3 using compound a shown as formula 1-3 and compound B shown as formula 2-2;
example 4 using compound a shown as formulas 1 to 4 and compound B shown as formulas 2 to 4;
example 5 using compound a shown as formulas 1 to 5 and compound B shown as formulas 2 to 5;
example 6 using compound a shown as formula 1-2 and compound B shown as formula 2-6;
comparative example 1 did not use compound a and compound B;
comparative example 2 used only compound a as shown in formulas 1-2, and did not use compound B;
comparative example 3 used only compound B as shown in formula 2-1, and did not use compound a;
the amounts of the respective raw materials added in examples 1 to 13 and comparative examples 1 to 3 are shown in Table 1.
Table 1 amounts of each raw material to be added in examples 1 to 13 and comparative examples 1 to 3
The lithium ion battery electrolyte prepared in examples 1 to 13 and comparative examples 1 to 3 is used for preparing a lithium ion battery, and the preparation method is as follows:
mixing nickel cobalt lithium manganate (NCM 523), a positive electrode binder (PVDF), carbon (C) and conductive carbon black (Super-P) according to a mass ratio of 95.5:2:1:1.5 to prepare positive electrode slurry;
mixing carbon (C), conductive carbon black (Super-P), carboxymethyl cellulose (CMC) and Styrene Butadiene Rubber (SBR) according to a mass ratio of 95.9:0.5:1.5:2.1 to prepare negative electrode slurry;
coating positive electrode slurry on an aluminum foil current collector, coating negative electrode slurry on the copper foil current collector, and drying to obtain a positive electrode plate and a negative electrode plate;
and then packaging the positive electrode plate, the negative electrode plate and the polyethylene diaphragm, drying, injecting 6.5 g into the electrolyte prepared in the examples 1-13 and the comparative examples 1-3, and performing chemical formation to obtain the lithium ion battery, and testing the electrical property of the lithium ion battery.
Performance test:
(1) Storage capacity retention at 70 ℃): the prepared lithium ion battery was placed in an oven at 70 ℃ and stored for 28 days, and then placed in a battery test system (new wei test system CT-ZWJ-4's-T-1U) to be discharged at 1C, and the capacity retention rate thereof was tested, and the capacity retention rate=the discharge capacity after storage/the discharge capacity before storage.
(2) Cycle capacity retention at 60 ℃): and placing the prepared lithium ion battery in a 60 ℃ oven, connecting a battery test system (Xinwei test system CT-ZWJ-4' S-T-1U), charging to 4.35V by 1C (the charge cut-off current is 0.05C), discharging to 2.75V by 1C, and testing the capacity retention rate of the lithium ion battery in a cyclic charge-discharge process for 200 weeks.
The test results of lithium ion batteries prepared by using the lithium ion battery electrolytes prepared in examples 1 to 13 and comparative examples 1 to 3 are shown in table 2.
Table 2 test results
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Claims (10)
1. The lithium ion battery electrolyte is characterized by comprising lithium salt, a solvent, a film forming additive and a film forming modifier;
the film forming modifier comprises a compound A shown in a formula 1 and a compound B shown in a formula 2;
；
wherein R is 1 Is hydrogen, C 3 ~C 6 Silane group, halogen, optionally substituted amino group, optionally substituted C 1 ~C 7 Or optionally substituted C 3 ~C 9 Any one of the alkylene groups of (2);
R 2 and R is 3 Each independently selected from hydrogen, C 3 ~C 6 Silane groups, halogen, optionally substituted C 1 ~C 7 Or optionally substituted C 3 ~C 9 Any one of the alkenyl groups of (2).
2. The lithium ion battery electrolyte according to claim 1, wherein the mass percentage of the compound A in the lithium ion battery electrolyte is 0.1-3%;
the mass percentage of the compound B in the lithium ion battery electrolyte is 0.1-3%;
the molar ratio of the compound A to the compound B is 1.5-2.5:1.
3. The lithium-ion battery electrolyte according to claim 1 or 2, wherein R 1 Comprising halogen, unsubstituted C 1 ~C 3 C substituted by alkyl, halogen 1 ~C 3 Alkyl or C of (2) 3 ~C 6 Any one of vinyl groups of (2);
the R is 2 And R is 3 Each independently comprises unsubstituted C 1 ~C 6 C substituted by alkyl, amino 1 ~C 6 Alkyl or silyl groups of (a).
4. The lithium ion battery electrolyte according to claim 1 or 2, wherein the structure of the compound a comprises one or more of the compounds of the following formula;
5. the lithium ion battery electrolyte according to claim 1 or 2, wherein the compound B comprises one or more of the following compounds;
6. the lithium ion battery electrolyte according to claim 1, wherein the film-forming additive comprises one or more of carbonates, sulfates, phosphoric acids, boric acids, silanes, fluorocarbons, fluorosulfates, fluorophosphoric acids, fluoroboric acids, or fluorosilanes;
the mass percentage of the film forming additive in the lithium ion battery electrolyte is 0.05-5%.
7. The lithium-ion battery electrolyte of claim 1, wherein the solvent comprises a carbonate-based organic solvent.
8. The lithium ion battery electrolyte of claim 1 or 7, wherein the solvent comprises ethylene carbonate, diethyl carbonate, and ethylmethyl carbonate;
the mass ratio of the ethylene carbonate to the diethyl carbonate to the ethylmethyl carbonate is 3:2:5.
9. The lithium ion battery electrolyte of claim 1, wherein the lithium salt comprises one or more of lithium hexafluorophosphate, lithium bis (oxalato) borate, lithium difluoro (oxalato) borate, lithium bis (trifluoromethylsulfonyl) imide, lithium bis (fluorosulfonyl) imide, lithium difluoro (fluorophosphate), lithium tetrafluoroborate, or lithium difluoro (bisoxalato) phosphate;
the mass percentage of the lithium salt in the lithium ion battery electrolyte is 7.5% -18.5%.
10. A lithium ion battery, characterized in that the lithium ion battery comprises the lithium ion battery electrolyte as claimed in any one of claims 1 to 9.
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