CN117810534A - Electrolyte, formation method of lithium ion battery and lithium ion battery - Google Patents
Electrolyte, formation method of lithium ion battery and lithium ion battery Download PDFInfo
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- CN117810534A CN117810534A CN202311791289.9A CN202311791289A CN117810534A CN 117810534 A CN117810534 A CN 117810534A CN 202311791289 A CN202311791289 A CN 202311791289A CN 117810534 A CN117810534 A CN 117810534A
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- 230000015572 biosynthetic process Effects 0.000 title claims abstract description 142
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 64
- 239000003792 electrolyte Substances 0.000 title claims abstract description 64
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 64
- 238000000034 method Methods 0.000 title claims abstract description 29
- 239000000654 additive Substances 0.000 claims abstract description 105
- 230000000996 additive effect Effects 0.000 claims abstract description 104
- -1 sulfonate compound Chemical class 0.000 claims abstract description 27
- 125000004432 carbon atom Chemical group C* 0.000 claims abstract description 25
- 239000003960 organic solvent Substances 0.000 claims abstract description 9
- 125000004450 alkenylene group Chemical group 0.000 claims abstract description 8
- 125000002947 alkylene group Chemical group 0.000 claims abstract description 8
- 229910003002 lithium salt Inorganic materials 0.000 claims abstract description 8
- 159000000002 lithium salts Chemical class 0.000 claims abstract description 8
- 125000004093 cyano group Chemical group *C#N 0.000 claims abstract description 7
- SBLRHMKNNHXPHG-UHFFFAOYSA-N 4-fluoro-1,3-dioxolan-2-one Chemical compound FC1COC(=O)O1 SBLRHMKNNHXPHG-UHFFFAOYSA-N 0.000 claims description 27
- 239000007774 positive electrode material Substances 0.000 claims description 13
- 150000001875 compounds Chemical class 0.000 claims description 11
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 7
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 claims description 6
- 229910045601 alloy Inorganic materials 0.000 claims description 6
- 239000000956 alloy Substances 0.000 claims description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 6
- FKRCODPIKNYEAC-UHFFFAOYSA-N ethyl propionate Chemical compound CCOC(=O)CC FKRCODPIKNYEAC-UHFFFAOYSA-N 0.000 claims description 6
- TZIHFWKZFHZASV-UHFFFAOYSA-N methyl formate Chemical compound COC=O TZIHFWKZFHZASV-UHFFFAOYSA-N 0.000 claims description 6
- 239000007773 negative electrode material Substances 0.000 claims description 5
- GWAOOGWHPITOEY-UHFFFAOYSA-N 1,5,2,4-dioxadithiane 2,2,4,4-tetraoxide Chemical compound O=S1(=O)CS(=O)(=O)OCO1 GWAOOGWHPITOEY-UHFFFAOYSA-N 0.000 claims description 4
- GZPHSAQLYPIAIN-UHFFFAOYSA-N 3-pyridinecarbonitrile Chemical compound N#CC1=CC=CN=C1 GZPHSAQLYPIAIN-UHFFFAOYSA-N 0.000 claims description 4
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 claims description 4
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 claims description 4
- JGFBQFKZKSSODQ-UHFFFAOYSA-N Isothiocyanatocyclopropane Chemical compound S=C=NC1CC1 JGFBQFKZKSSODQ-UHFFFAOYSA-N 0.000 claims description 4
- PWLNAUNEAKQYLH-UHFFFAOYSA-N butyric acid octyl ester Natural products CCCCCCCCOC(=O)CCC PWLNAUNEAKQYLH-UHFFFAOYSA-N 0.000 claims description 4
- UUIQMZJEGPQKFD-UHFFFAOYSA-N n-butyric acid methyl ester Natural products CCCC(=O)OC UUIQMZJEGPQKFD-UHFFFAOYSA-N 0.000 claims description 4
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 claims description 4
- 239000002153 silicon-carbon composite material Substances 0.000 claims description 4
- FSSPGSAQUIYDCN-UHFFFAOYSA-N 1,3-Propane sultone Chemical compound O=S1(=O)CCCO1 FSSPGSAQUIYDCN-UHFFFAOYSA-N 0.000 claims description 3
- UHOPWFKONJYLCF-UHFFFAOYSA-N 2-(2-sulfanylethyl)isoindole-1,3-dione Chemical compound C1=CC=C2C(=O)N(CCS)C(=O)C2=C1 UHOPWFKONJYLCF-UHFFFAOYSA-N 0.000 claims description 3
- LIEQVZZZYLHNRH-UHFFFAOYSA-N 5-methylpyridine-2-carbonitrile Chemical compound CC1=CC=C(C#N)N=C1 LIEQVZZZYLHNRH-UHFFFAOYSA-N 0.000 claims description 3
- 229910007857 Li-Al Inorganic materials 0.000 claims description 3
- 229910008447 Li—Al Inorganic materials 0.000 claims description 3
- 229910001128 Sn alloy Inorganic materials 0.000 claims description 3
- 229910020923 Sn-O Inorganic materials 0.000 claims description 3
- 229910010248 TiO2—Li4Ti5O12 Inorganic materials 0.000 claims description 3
- 125000003545 alkoxy group Chemical group 0.000 claims description 3
- 125000000217 alkyl group Chemical group 0.000 claims description 3
- 229910021383 artificial graphite Inorganic materials 0.000 claims description 3
- 229910052799 carbon Inorganic materials 0.000 claims description 3
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 claims description 3
- VEWLDLAARDMXSB-UHFFFAOYSA-N ethenyl sulfate;hydron Chemical compound OS(=O)(=O)OC=C VEWLDLAARDMXSB-UHFFFAOYSA-N 0.000 claims description 3
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 claims description 3
- 125000005843 halogen group Chemical group 0.000 claims description 3
- 229910021385 hard carbon Inorganic materials 0.000 claims description 3
- 125000004435 hydrogen atom Chemical group [H]* 0.000 claims description 3
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 claims description 3
- DVATZODUVBMYHN-UHFFFAOYSA-K lithium;iron(2+);manganese(2+);phosphate Chemical compound [Li+].[Mn+2].[Fe+2].[O-]P([O-])([O-])=O DVATZODUVBMYHN-UHFFFAOYSA-K 0.000 claims description 3
- 229910021382 natural graphite Inorganic materials 0.000 claims description 3
- UHPIOPMELXIDLL-UHFFFAOYSA-N pyridine-3,5-dicarbonitrile Chemical compound N#CC1=CN=CC(C#N)=C1 UHPIOPMELXIDLL-UHFFFAOYSA-N 0.000 claims description 3
- 229910021384 soft carbon Inorganic materials 0.000 claims description 3
- 229910052596 spinel Inorganic materials 0.000 claims description 3
- 239000011029 spinel Substances 0.000 claims description 3
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 claims description 3
- VDWQWOXVBXURMT-UHFFFAOYSA-N 5-methylpyridine-3-carbonitrile Chemical compound CC1=CN=CC(C#N)=C1 VDWQWOXVBXURMT-UHFFFAOYSA-N 0.000 claims description 2
- YXHPFSCDWSLLRT-UHFFFAOYSA-N pyridine-2,5-dicarbonitrile Chemical compound N#CC1=CC=C(C#N)N=C1 YXHPFSCDWSLLRT-UHFFFAOYSA-N 0.000 claims description 2
- 230000000694 effects Effects 0.000 abstract description 13
- 230000002708 enhancing effect Effects 0.000 abstract description 6
- 238000005755 formation reaction Methods 0.000 description 137
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- 230000014759 maintenance of location Effects 0.000 description 8
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- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 3
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- 229910052744 lithium Inorganic materials 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- 230000002195 synergetic effect Effects 0.000 description 3
- BTBUEUYNUDRHOZ-UHFFFAOYSA-N Borate Chemical compound [O-]B([O-])[O-] BTBUEUYNUDRHOZ-UHFFFAOYSA-N 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 229910013870 LiPF 6 Inorganic materials 0.000 description 2
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 2
- 239000002033 PVDF binder Substances 0.000 description 2
- 239000006256 anode slurry Substances 0.000 description 2
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- 229910002804 graphite Inorganic materials 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 229910000625 lithium cobalt oxide Inorganic materials 0.000 description 2
- VDVLPSWVDYJFRW-UHFFFAOYSA-N lithium;bis(fluorosulfonyl)azanide Chemical compound [Li+].FS(=O)(=O)[N-]S(F)(=O)=O VDVLPSWVDYJFRW-UHFFFAOYSA-N 0.000 description 2
- QSZMZKBZAYQGRS-UHFFFAOYSA-N lithium;bis(trifluoromethylsulfonyl)azanide Chemical compound [Li+].FC(F)(F)S(=O)(=O)[N-]S(=O)(=O)C(F)(F)F QSZMZKBZAYQGRS-UHFFFAOYSA-N 0.000 description 2
- IGILRSKEFZLPKG-UHFFFAOYSA-M lithium;difluorophosphinate Chemical compound [Li+].[O-]P(F)(F)=O IGILRSKEFZLPKG-UHFFFAOYSA-M 0.000 description 2
- BFZPBUKRYWOWDV-UHFFFAOYSA-N lithium;oxido(oxo)cobalt Chemical compound [Li+].[O-][Co]=O BFZPBUKRYWOWDV-UHFFFAOYSA-N 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
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- 239000002985 plastic film Substances 0.000 description 2
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- 229920003048 styrene butadiene rubber Polymers 0.000 description 2
- 238000009461 vacuum packaging Methods 0.000 description 2
- 238000004804 winding Methods 0.000 description 2
- FFNVQNRYTPFDDP-UHFFFAOYSA-N 2-cyanopyridine Chemical compound N#CC1=CC=CC=N1 FFNVQNRYTPFDDP-UHFFFAOYSA-N 0.000 description 1
- PBLOYQAQGYUPCM-UHFFFAOYSA-N 6-methylpyridine-3-carbonitrile Chemical compound CC1=CC=C(C#N)C=N1 PBLOYQAQGYUPCM-UHFFFAOYSA-N 0.000 description 1
- 229910013075 LiBF Inorganic materials 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 239000002174 Styrene-butadiene Substances 0.000 description 1
- HMDDXIMCDZRSNE-UHFFFAOYSA-N [C].[Si] Chemical class [C].[Si] HMDDXIMCDZRSNE-UHFFFAOYSA-N 0.000 description 1
- 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 description 1
- 239000006230 acetylene black Substances 0.000 description 1
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Abstract
The application relates to an electrolyte, a formation method of a lithium ion battery and the lithium ion battery. The electrolyte comprises an organic solvent, lithium salt, an additive A and an additive B, wherein the additive A is a sulfonate compound, and the additive B is a cyanopyridine compound; in the structural general formula (I-I) of the additive A, R 1 One selected from the group consisting of a substituted or unsubstituted alkylene group of 1 to 6 carbon atoms and a substituted or unsubstituted alkenylene group of 2 to 6 carbon atoms, R being in the general structural formula (I-II) of the additive A 2 One selected from a substituted or unsubstituted alkylene group of 1 to 6 carbon atoms, a substituted or unsubstituted alkenylene group of 2 to 6 carbon atoms; in the structural general formula of the additive B, X 1 、X 2 、X 3 、X 4 And X 5 At least one of which is cyano. According to the scheme, the formation gas yield can be reduced, the risk of cell bulge leakage is reduced, the formation temperature and formation current can be improved, and the effects of reducing cost and enhancing efficiency are achieved.
Description
Technical Field
The present disclosure relates to the field of lithium ion batteries, and in particular, to an electrolyte, a formation method of a lithium ion battery, and a lithium ion battery.
Background
The lithium ion battery is used as a clean and convenient energy source, plays a very important role in daily life of people, and more electrical equipment are required to be powered by the lithium ion battery.
The formation is an important step in the manufacture of lithium ion batteries, and is extremely critical to the performance of the lithium ion batteries. The main function of the formation is to form a layer of compact protective film on the surface of the negative electrode of the battery, thereby preventing the co-embedding of solvent molecules, avoiding the damage to the core material caused by the co-embedding of the solvent molecules, and improving the cycle performance and the service life of the battery core.
In order to achieve the purposes of cost reduction and efficiency enhancement in the process of manufacturing the battery cell, a mode of shortening formation time can be adopted. At present, a battery cell manufacturer mainly improves the formation reaction rate and the SEI film forming rate by improving the formation current or the formation temperature, so that the purpose of shortening the formation time is achieved. However, when the formation current is increased and the formation temperature is increased, a large amount of gas is generated during formation, the battery cell is at risk of bulge leakage, the SEI film stability is poor, and the cycle performance of the battery cell is finally deteriorated.
Disclosure of Invention
In order to solve or partially solve the problems in the related art, the application provides an electrolyte, a formation method of a lithium ion battery and the lithium ion battery, which can effectively reduce formation gas yield, reduce the risk of cell swelling and leakage, and improve formation temperature and formation current to achieve the effects of cost reduction and synergy.
The first aspect of the application provides an electrolyte, which comprises an organic solvent, lithium salt, an additive A and an additive B, wherein the additive A is a sulfonate compound, and the additive B is a cyanopyridine compound;
the additive A is selected from one or more of the following structural formulas (I-I), (I-II) and (I-III):
wherein R is 1 One selected from a substituted or unsubstituted alkylene group of 1 to 6 carbon atoms, a substituted or unsubstituted alkenylene group of 2 to 6 carbon atoms;
wherein R is 2 One selected from a substituted or unsubstituted alkylene group of 1 to 6 carbon atoms, a substituted or unsubstituted alkenylene group of 2 to 6 carbon atoms;
the structural general formula of the additive B is shown as the following formula II:
wherein X is 1 、X 2 、X 3 、X 4 And X 5 Each independently selected from the group consisting of a hydrogen atom, an alkyl group of 1 to 5 carbon atoms, an alkoxy group of 1 to 5 carbon atoms, a halogen atom, a cyano group, and an alkoxynitrile of 1 to 5 carbon atoms, and X 1 、X 2 、X 3 、X 4 And X 5 At least one of which is cyano.
In some embodiments of the present application, the mass ratio of the additive a in the electrolyte is a%, and the mass ratio of the additive B in the electrolyte is B%; wherein, a is more than or equal to 0.5% and less than or equal to 5%, b is more than or equal to 0.5% and less than or equal to 5%; preferably, 0.2.ltoreq.a/b.ltoreq.5.
In some embodiments of the present application, the organic solvent comprises at least two of fluoroethylene carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methylethyl carbonate, methyl formate, ethyl propionate, propyl propionate, methyl butyrate, tetrahydrofuran, one of which is fluoroethylene carbonate.
In some embodiments of the present application, the fluoroethylene carbonate comprises 10% w% to 30% w% of the electrolyte; preferably, 0.033.ltoreq.a/w.ltoreq.0.5.
In some embodiments of the present application, the additive a is selected from one or more of the following compounds: 1, 3-propane sultone, propenyl-1, 3-sultone, vinyl sulfate, methylene methane disulfonate;
and/or the additive B is selected from one or more of the following compounds: 3-cyanopyridine, 2-cyano-5-methylpyridine, 3, 5-dicyanopyridine, 5-cyanopyridine.
A second aspect of the present application provides a formation method of a lithium ion battery, the lithium ion battery comprising the electrolyte of the first aspect of the present application, wherein:
forming the lithium ion battery according to the second aspect of the application at the formation temperature T ℃ by MC charge-discharge multiplying power;
forming the lithium ion battery by using MC rate charging current, wherein M is more than or equal to 0.1 and less than or equal to 0.5; and/or
And (3) forming the lithium ion battery at the formation temperature of T ℃, wherein the range of T is more than or equal to 45 and less than or equal to 70.
In some embodiments of the present application, the mass ratio of the additive B in the electrolyte is defined as B%,0.5% B% 5%, 0.044% B/(t×m) 1.111.
A third aspect of the present application provides a lithium ion battery comprising an electrolyte as described in the first aspect of the present application or a method of formation as described in the second aspect of the present application.
In some embodiments of the present application, the lithium ion battery further comprises a positive electrode tab and a negative electrode tab;
the positive electrode plate comprises a positive electrode current collector and a positive electrode active layer arranged on the surface of the positive electrode current collector, wherein the positive electrode active layer comprises a positive electrode active material, and the positive electrode active material comprises one or more of lithium iron phosphate and lithium manganese iron phosphate;
and/or the negative electrode plate comprises a negative electrode current collector and a negative electrode active layer arranged on the surface of the negative electrode current collector, wherein the negative electrode active layer comprises a negative electrode active material, and the negative electrode active material comprises natural graphite, artificial graphite, mesophase micro carbon spheres, hard carbon, soft carbon, silicon-carbon composite, li-Sn alloy, li-Sn-O alloy and Sn, snO, snO 2 Or spinel structured lithiated TiO 2 -Li 4 Ti 5 O 12 One or more of Li-Al alloys.
In some embodiments of the present application, the positive electrode active material has a mass ratio of 80% to 99% in the positive electrode active layer, and the positive electrode active material does not contain an aluminum element.
The technical scheme that this application provided can include following beneficial effect: the application of the additive A sulfonate compound and the additive B cyano pyridine compound in the electrolyte can effectively reduce the formation gas production and reduce the risk of cell swelling and leakage; meanwhile, the SEI film with good stability can be formed, so that the deterioration of the formation temperature and formation current on the cell cycle performance is effectively relieved, the low-temperature cycle performance and the high-voltage high-temperature cycle performance of the battery are improved, the formation temperature and the formation current can be improved during formation, the formation time is shortened, and the effects of reducing cost and enhancing efficiency are achieved.
Detailed Description
In order that the invention may be readily understood, the invention will be described in detail. Before the present invention is described in detail, it is to be understood that this invention is not limited to particular embodiments described. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.
The terminology used in the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. As used in this application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any or all possible combinations of one or more of the associated listed items.
Where a range of values is provided, it is understood that each intervening value, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges, and are also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention. In the description of the present application, the meaning of "plurality" is two or more, unless explicitly defined otherwise.
Unless defined otherwise, all terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Although any methods and materials equivalent to those described herein can also be used in the practice or testing of the present invention, the preferred methods and materials are now described.
In order to achieve the purposes of cost reduction and efficiency enhancement in the process of manufacturing the battery cell, a mode of shortening formation time can be adopted. At present, a battery cell manufacturer mainly improves the formation reaction rate and the SEI film forming rate by improving the formation current or the formation temperature, so that the purpose of shortening the formation time is achieved. However, when the formation current is increased and the formation temperature is increased, a large amount of gas is generated during formation, the battery cell is at risk of bulge leakage, the SEI film stability is poor, and the cycle performance of the battery cell is finally deteriorated.
Aiming at the problems, the embodiment of the application provides an electrolyte, a formation method of a lithium ion battery and the lithium ion battery, which can effectively reduce formation gas production, reduce the risk of cell bulge leakage, and improve formation temperature and formation current to achieve the effects of cost reduction and synergy.
The electrolyte provided by the embodiment of the application comprises an organic solvent, lithium salt, an additive A and an additive B, wherein the additive A is a sulfonate compound, and the additive B is a cyanopyridine compound.
Wherein the additive A is selected from one or more of the following structural formulas (I-I), (I-II) and (I-III):
R 1 one selected from a substituted or unsubstituted alkylene group of 1 to 6 carbon atoms, a substituted or unsubstituted alkenylene group of 2 to 6 carbon atoms;
R 2 one selected from a substituted or unsubstituted alkylene group of 1 to 6 carbon atoms, a substituted or unsubstituted alkenylene group of 2 to 6 carbon atoms;
the structural general formula of the additive B is shown as the following formula II:
X 1 、X 2 、X 3 、X 4 and X 5 Each independently selected from the group consisting of a hydrogen atom, an alkyl group of 1 to 5 carbon atoms, an alkoxy group of 1 to 5 carbon atoms, a halogen atom, a cyano group, and an alkoxynitrile of 1 to 5 carbon atoms, and X 1 、X 2 、X 3 、X 4 And X 5 At least one of which is cyano.
In the electrolyte of the embodiment of the application, the additive B cyanopyridine compound has the function of capturing hydrogen radicals, and when the formation temperature and the formation current are increased, the additive B can capture a large amount of hydrogen radicals generated by the decomposition of the electrolyte, so that the increase of formation gas yield caused by the rapid decomposition of solvent components and electrolyte components in the electrolyte is avoided, and the purpose of effectively increasing the formation temperature and the formation current of a battery is achieved; meanwhile, the additive B can participate in film formation at the positive electrode, so that the cycle performance of the battery under the conditions of high voltage and high temperature is improved, but the additive B can increase the impedance of the negative electrode side, and the low-temperature cycle performance of the battery is deteriorated. The additive A sulfonate compound can form an SEI film with good stability and low interface impedance on a negative electrode, so that the lithium ion migration speed and the electron conduction speed in a lithium ion battery are improved, and the low-temperature cycle performance of the battery is improved. Therefore, when the additive A and the additive B are combined, the formation gas yield and the risk of cell bulge leakage can be effectively reduced, and the formation temperature and formation current can be increased, so that the effects of reducing the cost and enhancing the efficiency are achieved. Moreover, the combination of the additive A and the additive B can relieve the deterioration of the cycle performance of the battery caused by the formation current improvement, and improve the low-temperature cycle performance and the high-voltage high-temperature cycle performance of the battery.
In some alternative embodiments, additive A may be selected from one or more of the compounds of formulae (I-I), (I-II), and (I-III), or may be selected from one or more of the compounds of formula (I). Preferably, additive a may be selected from one or more of the following compounds: 1, 3-Propane Sultone (PS), propenyl-1, 3-sultone (PES), vinyl sulfate (DTD), methylene Methane Disulfonate (MMDS).
In some alternative embodiments, additive B may be selected from a mixture of one or more compounds of formula II. Preferably, additive B may be selected from one or more of the following compounds: 2-cyanopyridine, 3-cyanopyridine, 2-cyano-5-methylpyridine, 3-cyano-5-methylpyridine, 5-cyano-2-methylpyridine, 2, 5-dicyanopyridine, 3, 5-dicyanopyridine; wherein, the structural formula of the compound of the partial additive B is shown as follows:
in some alternative embodiments, the mass ratio of additive A in the electrolyte is a%, satisfying 0.5% to 5% a, for example, 0.5%, 1%, 2%, 3%, 4%, 5%, etc., and any other value within the above range. When the mass ratio of the additive A is in the range, the formation gas yield can be effectively reduced, meanwhile, the interface impedance of the SEI film is reduced, and the low-temperature cycle performance of the battery is improved.
In some alternative embodiments, the mass ratio of additive B in the electrolyte is B%, satisfying 0.5% to 5% B, for example, 0.5%, 1%, 2%, 3%, 4%, 5%, etc., and any other value within the above range. When the mass ratio of the additive B is in the range, the formation gas yield can be well reduced, the protection of the positive electrode is enhanced, and the high-temperature cycle performance of the battery is improved.
In some preferred embodiments, the mass ratio of additive a and additive B in the electrolyte is such that: a/b is more than or equal to 0.2 and less than or equal to 5. The addition of excessive additive A or additive B can increase the viscosity of the electrolyte, reduce the fluidity of the electrolyte and increase the impedance of an interface film, so that the low-temperature cycle performance is deteriorated, and the excessive additive A can accelerate the decomposition of the electrolyte in a high-voltage (more than or equal to 4.55V) high-temperature (more than or equal to 60 ℃) environment, so that the high-voltage high-temperature cycle performance of a battery is deteriorated; the added additive B can well capture hydrogen radicals in the electrolyte, raise formation temperature and formation current, reduce formation gas yield, strengthen positive electrode protection, inhibit decomposition of the additive A on the positive electrode side, and improve high-voltage and high-temperature cycle performance of the battery. Therefore, the mass ratio of the additive A to the additive B in the electrolyte is limited in the range, and the proportion of the additive A to the additive B is coordinated, so that the synergistic effect of the additive A and the additive B can be better exerted, the formation current and the formation temperature are improved, the formation time is shortened, and the effect of reducing the cost and enhancing the efficiency is achieved; meanwhile, the formation gas yield is reduced, and the low-temperature cycle performance and the high-voltage high-temperature cycle performance of the battery are improved.
In some preferred embodiments, the organic solvent comprises at least two of fluoroethylene carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methylethyl carbonate, methyl formate, ethyl propionate, propyl propionate, methyl butyrate, tetrahydrofuran, one of which is fluoroethylene carbonate. Fluoroethylene carbonate (FEC) has good effect of improving the cycle performance of the battery, when the FEC is added into the electrolyte, the formation can produce a large amount of gas, and the battery cell also has the risk of swelling and leaking liquid, which causes certain trouble to production. When the FEC in the electrolyte is combined with the additive A and the additive B, the additive A can be subjected to preferential FEC reduction and forms a film on the negative electrode in advance, so that the formation gas yield is effectively reduced, the risk of cell swelling and leakage is reduced, and the additive B can capture a large amount of hydrogen free radicals generated by the decomposition of the electrolyte, so that the FEC and other components in the electrolyte are prevented from being decomposed by the hydrogen free radicals, and the formation gas yield is further reduced. Therefore, when the additive A sulfonate compound, the additive B cyanopyridine compound and the fluoroethylene carbonate are used together, the high-temperature and low-temperature cycle performance of the battery can be greatly improved, and meanwhile, the gas yield can be greatly reduced, and the method is beneficial to being applied to the battery preparation process with the formation temperature and the formation current being improved, so that the formation time is shortened, and the effects of reducing the cost and improving the efficiency are achieved.
In some preferred embodiments, the fluoroethylene carbonate is present in the electrolyte at a weight percent w%, satisfying 10% w% 30%, such as 10%, 15%, 20%, 25%, 30, etc., and any other value within the above range.
In some preferred embodiments, the lithium salt may include lithium hexafluorophosphate (LiPF 6 ) Lithium difluorooxalato borate (LiODFB), lithium bisoxalato borate (LiBOB), lithium difluorodioxaato phosphate (LiDFOP), lithium tetrafluoroborate (LiBF) 4 ) Lithium bis (trifluoromethylsulfonyl) imide (LiTFSI), lithium bis (fluorosulfonyl) imide (LiFSI), lithium difluorophosphate (LiPO) 2 F 2 ) One or more of (a) and (b).
The electrolyte is one of the main materials of lithium ion batteries, and is one of the important factors affecting the performance of the lithium ion secondary batteries. The solvent, the lithium salt and the additive are main components of the electrolyte, and have great influence on the performances of the battery, such as circulation, impedance, dynamics and the like. According to the embodiment of the application, parameters such as the composition of the electrolyte, the content of the additive A sulfonate compound and the additive B cyanopyridine compound in the electrolyte, the proportion of the additive A sulfonate compound and the additive B cyanopyridine compound and the organic solvent fluoroethylene carbonate are comprehensively designed, and the synergistic coordination among the components in the electrolyte is utilized, so that the purpose of reducing the formation gas yield is achieved, the risk of cell swelling and leakage is further reduced, the formation temperature and formation current can be improved to form a battery, the formation time is shortened, and the effects of reducing the cost and improving the efficiency are achieved; meanwhile, the degradation of the formation temperature and the formation current on the battery cycle performance can be relieved, and the low-temperature and high-pressure cycle performance of the battery is improved.
The lithium ion battery provided by the embodiment of the application comprises electrolyte, a positive pole piece, a negative pole piece and a separation membrane, wherein the positive pole piece, the negative pole piece and the separation membrane are immersed in the electrolyte. The positive electrode plate comprises a positive electrode current collector and a positive electrode active layer arranged on the surface of the positive electrode current collector, wherein the positive electrode current collector can be selected from metal foil or a composite current collector, such as aluminum foil; the negative electrode tab includes a negative electrode current collector and a negative electrode active layer disposed on a surface of the negative electrode current collector, which may be selected from a metal foil or a composite current collector, such as a copper foil.
In some alternative embodiments, the positive electrode active layer includes a positive electrode active material, which may be selected from one or more of lithium iron phosphate, lithium manganese iron phosphate. Preferably, the positive electrode active material does not contain an aluminum element.
In some alternative embodiments, the mass fraction of the positive electrode active material in the positive electrode active layer is 80% to 99%.
In some alternative embodiments, the anode active layer comprises an anode active material, which may be selected from natural graphite, artificial graphite, mesophase micro carbon spheres, hard carbon, soft carbon, silicon-carbon composites, li-Sn alloys, li-Sn-O alloys, sn, snO, snO 2 Or spinel structured lithiated TiO 2 -Li 4 Ti 5 O 12 One or more of Li-Al alloys; preferably graphite or a silicon-carbon composite.
In the embodiment of the application, the positive pole piece, the negative pole piece and the isolating film can be manufactured into the battery core through a winding process or a lamination process, the battery core is arranged in an aluminum plastic film which is formed by punching, the battery core is baked, electrolyte is injected into the baked and dried battery core, and then the preparation of the lithium ion battery is completed after the procedures of vacuum packaging, standing, formation and the like are carried out. During formation, a compact SEI film is formed on the surface of a battery cell negative electrode, the electrolyte A sulfonate compound can form a film on the surface of the negative electrode in advance in preference to FEC reduction, the compact SEI film with low interface impedance can be formed based on the combination of the electrolyte A and fluoroethylene carbonate FEC, and the electrolyte B cyanopyridine compound can participate in positive electrode film forming, so that the combination of the electrolyte A, the electrolyte B, an organic solvent, lithium salt and the like is adopted, and the low-temperature cycle performance and the high-voltage high-temperature cycle performance of the battery can be effectively improved by the cooperation of the components, and the gas production rate can be effectively reduced.
The formation of the lithium ion battery can be performed by simultaneously increasing the formation current and the formation temperature, so that the formation time is shortened, and the effects of reducing the cost and enhancing the efficiency are achieved.
The formation method of the lithium ion battery in the embodiment of the application may be to form the lithium ion battery with the charging current of the MC multiplying power, where M is 0.1-0.5, for example, 0.1C, 0.2C, 0.3C, 0.4C, 0.5C, or any value in the above range.
The formation method of the lithium ion battery in the embodiment of the present application may be a formation method of the lithium ion battery at a formation temperature of T ℃, where T is 45.ltoreq.t.ltoreq.70, for example, 45 ℃, 50 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃ and the like, and may be any value within the above range. As the formation temperature is increased, the formation gas yield is increased, and the cohesiveness of the isolating film is enhanced, so that the battery core of the lithium ion battery is more compact, namely the compactness between the negative electrode plate and the positive electrode plate is improved, and the lithium ions are more smoothly transmitted in the battery; however, as the formation temperature is continuously increased, when the formation temperature is too high, the SEI film structure formed by the negative electrode of the battery cell becomes fluffy, the density is reduced, the stability of the interface film is reduced, and the cycle performance of the battery is deteriorated.
According to the formation method of the lithium ion battery, the formation temperature and the formation current can be improved, the formation time can be shortened, the production cost is reduced, and the cycle performance of the battery is improved. When the formation temperature is too low, the formation film forming speed is too slow, the diaphragm adhesion is poor, and the cycle performance is easy to deteriorate; when the formation temperature is too high, the SEI film is too fluffy, the energy consumption is increased, and the formation gas yield is increased sharply; when the formation current is lower, the formation time is longer, and the production cost is increased; when the formation current is higher, the formation gas yield increases dramatically, and the SEI film performance is unstable, deteriorating the cycle performance. Therefore, when the formation temperature is controlled to be less than or equal to 45 ℃ and less than or equal to 70 ℃ and the formation current is controlled to be less than or equal to 0.1 ℃ and less than or equal to MC and less than or equal to 0.5 ℃, the whole cycle performance of the battery can be improved on the premise of controlling the cost.
In some alternative embodiments, the mass ratio of additive B in the electrolyte is such that the relationship between the formation temperature and formation current of the lithium ion battery: b/(T.times.M) is less than or equal to 0.044 and less than or equal to 1.111. According to the lithium ion battery, the formation temperature and the formation current can be regulated according to the electrolyte component, when the relationship among the formation temperature, the charge-discharge multiplying power of formation and the cyanopyridine compound of the additive B meets the conditions, the additive B can effectively capture hydrogen free radicals, and the gas production rate is effectively controlled under the condition of improving the formation current and the formation temperature, so that an SEI film with stable performance is formed on the surface of a negative electrode of a battery core, and the overall cycle performance of the battery is improved; meanwhile, the energy consumption can be reduced, the production cost is reduced, and the effects of reducing the cost and enhancing the efficiency are achieved.
The lithium ion battery provided by the embodiment of the application is suitable for an electric device or various energy storage systems using the battery as an energy storage element. The electric device comprises, but is not limited to, a mobile phone, a tablet, a computer, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft and the like.
In order that the invention may be more readily understood, a more particular description of the invention will be rendered by reference to specific examples that are illustrated below. All references to the following examples are in weight percent. It should be noted that the following examples are not exhaustive of all possible scenarios, and that the materials used in the examples described below are commercially available unless otherwise specified.
Example 1
(1) Preparation of electrolyte
Mixing ethylene carbonate EC, diethyl carbonate DEC and propylene carbonate PC in a mass ratio of 1:1:1, adding fluoroethylene carbonate FEC, an additive A sulfonate compound and an additive B cyanopyridine compound in mass percentages shown in table 1 based on the total mass of the electrolyte, uniformly mixing, and then adding lithium salt (LiPF 6 ) And obtaining electrolyte.
(2) Preparation of positive electrode plate
Lithium cobalt oxide (LiCoO) as a positive electrode active material 2 ) The conductive agent carbon nano tube CNT and the binder polyvinylidene fluoride PVDF are fully stirred and mixed in an N-methylpyrrolidone NMP solvent according to the mass ratio of 97:1.5:1.5, so that uniform anode slurry is formed; uniformly coating anode slurry on an anode current collector aluminum foil to form an anode active layer; and drying, cold pressing and other steps to obtain the positive pole piece.
(3) Preparation of negative electrode plate
The preparation method comprises the steps of fully stirring and mixing negative electrode active material graphite, conductive agent acetylene black, adhesive styrene butadiene rubber SBR and thickener sodium carboxymethylcellulose in a mass ratio of 96:1.2:1.5:1.3 in a proper amount of deionized water solvent to form uniform negative electrode slurry; and uniformly coating the negative electrode slurry on a negative electrode current collector copper foil, and obtaining a negative electrode plate through procedures such as drying, cold pressing and the like.
(4) Preparation of lithium ion batteries
PE porous polymer film is used as a separation film.
And sequentially stacking the positive electrode plate, the isolating film and the negative electrode plate, enabling the isolating film to be positioned between the positive electrode plate and the negative electrode plate, playing an isolating role, and winding the stacked electrode plate and the isolating film to obtain the bare cell. And (3) placing the bare cell in an aluminum-plastic film formed by punching, injecting the electrolyte prepared by the method into the baked and dried cell, and performing vacuum packaging, standing, formation (the formation current and the formation temperature are shown in table 1) and other procedures to complete the preparation of the lithium ion battery.
Examples 2 to 31 and comparative examples 1 to 7 were the same as example 1, with the differences shown in Table 1.
TABLE 1
Lithium ion battery performance test:
(1) And (3) 5 ℃ cyclic test:
the lithium ion battery was charged to 4.55V at a constant current and constant voltage of 1C in an incubator at (5±2) °c, the off current was 0.05C, and then 1C was set to 3V, and charge and discharge cycles were performed a plurality of times under the above conditions, and the capacity retention after 800 cycles of the battery was calculated, each group of 5 batteries, and the average value of the capacity retention after the cycle was recorded in table 2.
Capacity retention (%) = corresponding cycle number discharge capacity (mAh)/discharge capacity for the third cycle (mAh) 100%
(2) And (3) cyclic test at 60 ℃):
the lithium ion battery was charged to 4.55V at a constant current and constant voltage of 1C in an incubator at (60±2) °c, the off current was 0.05C, and then 1C was set to 3V, and charge and discharge cycles were performed a plurality of times under the above conditions, and the capacity retention after 800 cycles of the battery was calculated, each group of 5 batteries, and the average value of the capacity retention after the cycle was recorded in table 2.
Capacity retention (%) = corresponding cycle number discharge capacity (mAh)/discharge capacity for the third cycle (mAh) 100%
(3) And (3) testing formation gas production:
the thickness of the cells before and after formation was measured, the formation gas production of the cells was calculated, 5 cells each were used for each group, and the calculated formation thickness change rate/formation gas production was averaged and recorded in table 2.
The formation thickness change rate (%) = (thickness after formation-thickness before formation)/(thickness before formation) ×100%.
TABLE 2
From the data of comparative example 2 and comparative example 1, it is shown that the addition of additive a alone of comparative example 2 slightly improves the formation gas yield and the low-temperature cycle performance of lithium ions, but at the same time deteriorates the high-temperature cycle performance of lithium ion batteries, mainly because the interfacial film formed by the participation of additive a is easily decomposed at high voltage and high temperature, thereby deteriorating the high-temperature cycle performance.
From the data of comparative example 3 and comparative example 1, it is shown that the high-temperature cycle performance of the lithium ion battery is slightly improved by adding the additive B alone in comparative example 3, which benefits from the participation of the additive B in the positive electrode film formation, enhances the stability of the positive electrode material, and can reduce the formation yield, which is based on the fact that the additive B can capture hydrogen radicals generated in the formation process, and avoid further decomposition of the electrolyte, thereby reducing the formation gas. However, the additive B increases the interfacial film resistance and deteriorates the low-temperature cycle performance when added alone.
From the data of comparative examples 4-5 and examples 1-31, it is shown that when the additive A sulfonate compound and the additive B cyanopyridine compound are added simultaneously, the formation gas yield of the lithium ion battery is greatly reduced, the capacity retention rate of 800 weeks at 5 ℃ and the capacity retention rate of 800 weeks at 60 ℃ are greatly improved, the two can exert better synergistic effect, and all comprehensive performances of the lithium ion battery are remarkably improved.
From the data of comparative examples 1 and 5, it was revealed that as the formation current was increased, the formation gas yield was increased and the cycle performance was deteriorated. From the data of comparative examples 1 and 7, it is shown that as the formation temperature increases, the formation gas yield increases, and when the formation temperature is too high, the SEI film structure formed on the surface of the battery cell is relatively fluffy and unstable, and the cycle performance is simultaneously deteriorated.
From the data of examples 1 to 11, it is shown that when additive a and additive B satisfy (a: B) = (0.5 to 5): (0.5-5), and 0.2 is less than or equal to a/b is less than or equal to 5, the improvement on the low-temperature cycle performance, the high-temperature cycle performance and the reduction of the formation gas production of the lithium ion battery is obvious, wherein the comprehensive performance of the embodiment 2 is better.
The data of examples 1 to 11 and examples 21 to 24 show that the additive A added can reduce the gas production of the chemical components. However, when the amount of the additive A relative to fluoroethylene carbonate is too low, a good inhibition effect cannot be achieved, and as the amount of the additive A relative to fluoroethylene carbonate is increased, the formation gas yield improvement effect of the lithium ion battery is increased; when the dosage of the additive A relative to fluoroethylene carbonate is too high, the impedance of an interface film formed on the surface of the battery core is larger, so that the cycle performance of the lithium ion battery is deteriorated, the improvement on the formation of gas is not obvious, and the cost of the additive is increased. Therefore, the dosage of the additive A relative to fluoroethylene carbonate is limited to be more than or equal to 0.033 and less than or equal to 0.5, and all the comprehensive properties of the lithium ion battery are better.
The data of examples 17 to 21 and examples 26 to 31 show that the formation current is increased and the cycle performance of the lithium ion battery is not significantly deteriorated when the additives a and B are simultaneously present. As the formation temperature and current increase, the formation gas yield increases. If the content of the additive B is too low compared with the formation temperature and the formation current ratio, the aim of capturing a large amount of hydrogen radicals under high temperature and high current is not achieved; therefore, the dosage of the additive B relative to the formation temperature and the current is limited to be less than or equal to 0.044 and less than or equal to B/(T.times.M) and less than or equal to 1.111, and all the comprehensive performances of the lithium ion battery are better.
From the data of examples 12-16, it is shown that additive A and additive B can also use other compounds as described in the examples of the present application, and still provide good synergy.
It should be noted that the above-described embodiments are only for explaining the present application, and do not constitute any limitation to the present application. The present application has been described with reference to exemplary embodiments, but it is understood that the words which have been used are words of description and illustration, rather than words of limitation. Modifications may be made to the present application as defined within the scope of the claims of the present application, and the present application may be modified without departing from the scope and spirit of the present application. Although the present application is described herein with reference to particular methods, materials and embodiments, the present application is not intended to be limited to the particular examples disclosed, but, on the contrary, the present application is to be extended to all other methods and applications having the same functionality.
Claims (10)
1. The electrolyte is characterized by comprising an organic solvent, lithium salt, an additive A and an additive B, wherein the additive A is a sulfonate compound, and the additive B is a cyanopyridine compound;
the additive A is selected from one or more of the following structural formulas (I-I), (I-II) and (I-III):
wherein R is 1 One selected from a substituted or unsubstituted alkylene group of 1 to 6 carbon atoms, a substituted or unsubstituted alkenylene group of 2 to 6 carbon atoms;
wherein R is 2 One selected from a substituted or unsubstituted alkylene group of 1 to 6 carbon atoms, a substituted or unsubstituted alkenylene group of 2 to 6 carbon atoms;
the structural general formula of the additive B is shown as the following formula II:
wherein X is 1 、X 2 、X 3 、X 4 And X 5 Each independently selected from the group consisting of a hydrogen atom, an alkyl group of 1 to 5 carbon atoms, an alkoxy group of 1 to 5 carbon atoms, a halogen atom, a cyano group, and an alkoxynitrile of 1 to 5 carbon atoms, and X 1 、X 2 、X 3 、X 4 And X 5 At least one of which is cyano.
2. The electrolyte of claim 1, wherein:
the mass ratio of the additive A in the electrolyte is a percent, and the mass ratio of the additive B in the electrolyte is B percent; wherein, a is more than or equal to 0.5% and less than or equal to 5%, b is more than or equal to 0.5% and less than or equal to 5%; preferably, 0.2.ltoreq.a/b.ltoreq.5.
3. The electrolyte according to claim 2, wherein:
the organic solvent comprises at least two of fluoroethylene carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl formate, ethyl propionate, propyl propionate, methyl butyrate and tetrahydrofuran, wherein one of the fluoroethylene carbonate and the methyl butyrate is fluoroethylene carbonate.
4. The electrolyte according to claim 3, wherein:
the mass ratio of the fluoroethylene carbonate in the electrolyte is w%, and is more than or equal to 10% and less than or equal to 30%; preferably, 0.033.ltoreq.a/w.ltoreq.0.5.
5. The electrolyte of claim 1, wherein:
the additive A is selected from one or more of the following compounds: 1, 3-propane sultone, propenyl-1, 3-sultone, vinyl sulfate, methylene methane disulfonate; and/or
The additive B is selected from one or more of the following compounds: 3-cyanopyridine, 2-cyano-5-methylpyridine, 3-cyano-5-methylpyridine, 2, 5-dicyanopyridine, 3, 5-dicyanopyridine.
6. A method of forming a lithium ion battery, wherein the lithium ion battery comprises the electrolyte of any one of claims 1 to 5, wherein:
forming the lithium ion battery by using MC rate charging current, wherein M is more than or equal to 0.1 and less than or equal to 0.5; and/or
And (3) forming the lithium ion battery at the formation temperature of T ℃, wherein the range of T is more than or equal to 45 and less than or equal to 70.
7. The method of forming according to claim 6, wherein:
the mass ratio of the additive B in the electrolyte is defined as b%, b% is more than or equal to 0.5% and less than or equal to 5%, and B/(T.times.M) is more than or equal to 0.044 and less than or equal to 1.111.
8. A lithium ion battery comprising the electrolyte according to any one of claims 1 to 5 or produced according to the formation method of claim 6 or 7.
9. The lithium ion battery of claim 8, further comprising a positive electrode tab and a negative electrode tab;
the positive electrode plate comprises a positive electrode current collector and a positive electrode active layer arranged on the surface of the positive electrode current collector, wherein the positive electrode active layer comprises a positive electrode active material, and the positive electrode active material comprises one or more of lithium iron phosphate and lithium manganese iron phosphate;
and/or the negative electrode plate comprises a negative electrode current collector and a negative electrode active layer arranged on the surface of the negative electrode current collector, wherein the negative electrode active layer comprises a negative electrode active material, and the negative electrode active material comprises natural graphite, artificial graphite, mesophase micro carbon spheres, hard carbon, soft carbon, silicon-carbon composite, li-Sn alloy, li-Sn-O alloy and Sn, snO, snO 2 Or spinel structured lithiated TiO 2 -Li 4 Ti 5 O 12 One or more of Li-Al alloys.
10. The lithium ion battery according to claim 9, wherein the mass ratio of the positive electrode active material in the positive electrode active layer is 80% to 99%, and the positive electrode active material contains no aluminum element.
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