CN115588780A - Non-aqueous electrolyte and lithium ion battery thereof - Google Patents
Non-aqueous electrolyte and lithium ion battery thereof Download PDFInfo
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- CN115588780A CN115588780A CN202211255008.3A CN202211255008A CN115588780A CN 115588780 A CN115588780 A CN 115588780A CN 202211255008 A CN202211255008 A CN 202211255008A CN 115588780 A CN115588780 A CN 115588780A
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- 239000011255 nonaqueous electrolyte Substances 0.000 title claims abstract description 25
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 title claims abstract description 18
- 229910001416 lithium ion Inorganic materials 0.000 title claims abstract description 15
- 239000000654 additive Substances 0.000 claims abstract description 32
- 230000000996 additive effect Effects 0.000 claims abstract description 30
- 229910003002 lithium salt Inorganic materials 0.000 claims abstract description 29
- 159000000002 lithium salts Chemical class 0.000 claims abstract description 29
- 229910052736 halogen Inorganic materials 0.000 claims abstract description 23
- 239000011356 non-aqueous organic solvent Substances 0.000 claims abstract description 11
- 125000003837 (C1-C20) alkyl group Chemical group 0.000 claims abstract description 8
- 125000003884 phenylalkyl group Chemical group 0.000 claims abstract description 8
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 claims abstract description 7
- 125000002029 aromatic hydrocarbon group Chemical group 0.000 claims abstract description 6
- -1 sulfonate compound Chemical class 0.000 claims description 26
- 150000002367 halogens Chemical group 0.000 claims description 17
- 239000003792 electrolyte Substances 0.000 claims description 16
- 239000008151 electrolyte solution Substances 0.000 claims description 14
- BTGRAWJCKBQKAO-UHFFFAOYSA-N adiponitrile Chemical compound N#CCCCCC#N BTGRAWJCKBQKAO-UHFFFAOYSA-N 0.000 claims description 10
- IAHFWCOBPZCAEA-UHFFFAOYSA-N succinonitrile Chemical compound N#CCCC#N IAHFWCOBPZCAEA-UHFFFAOYSA-N 0.000 claims description 10
- LNLFLMCWDHZINJ-UHFFFAOYSA-N hexane-1,3,6-tricarbonitrile Chemical compound N#CCCCC(C#N)CCC#N LNLFLMCWDHZINJ-UHFFFAOYSA-N 0.000 claims description 5
- 150000001875 compounds Chemical class 0.000 claims description 4
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 claims description 3
- 229910052731 fluorine Inorganic materials 0.000 claims description 3
- 239000011737 fluorine Substances 0.000 claims description 3
- 125000006267 biphenyl group Chemical group 0.000 claims 2
- ZUOUZKKEUPVFJK-UHFFFAOYSA-N diphenyl Chemical group C1=CC=CC=C1C1=CC=CC=C1 ZUOUZKKEUPVFJK-UHFFFAOYSA-N 0.000 abstract description 12
- 239000004305 biphenyl Chemical group 0.000 abstract description 6
- 235000010290 biphenyl Nutrition 0.000 abstract description 6
- 125000005843 halogen group Chemical group 0.000 abstract 6
- SBLRHMKNNHXPHG-UHFFFAOYSA-N 4-fluoro-1,3-dioxolan-2-one Chemical compound FC1COC(=O)O1 SBLRHMKNNHXPHG-UHFFFAOYSA-N 0.000 description 16
- HMDDXIMCDZRSNE-UHFFFAOYSA-N [C].[Si] Chemical compound [C].[Si] HMDDXIMCDZRSNE-UHFFFAOYSA-N 0.000 description 10
- 239000007773 negative electrode material Substances 0.000 description 8
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 6
- 239000002002 slurry Substances 0.000 description 5
- 229920003171 Poly (ethylene oxide) Polymers 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- 229910002804 graphite Inorganic materials 0.000 description 4
- 239000010439 graphite Substances 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000007246 mechanism Effects 0.000 description 4
- 229920001184 polypeptide Polymers 0.000 description 4
- 239000007774 positive electrode material Substances 0.000 description 4
- 102000004196 processed proteins & peptides Human genes 0.000 description 4
- 108090000765 processed proteins & peptides Proteins 0.000 description 4
- FSSPGSAQUIYDCN-UHFFFAOYSA-N 1,3-Propane sultone Chemical compound O=S1(=O)CCCO1 FSSPGSAQUIYDCN-UHFFFAOYSA-N 0.000 description 3
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 239000010703 silicon Substances 0.000 description 3
- 229910052710 silicon Inorganic materials 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 229910013870 LiPF 6 Inorganic materials 0.000 description 2
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 2
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 2
- 230000009471 action Effects 0.000 description 2
- 150000004945 aromatic hydrocarbons Chemical class 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 239000002131 composite material Substances 0.000 description 2
- 239000006258 conductive agent Substances 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- FKRCODPIKNYEAC-UHFFFAOYSA-N ethyl propionate Chemical compound CCOC(=O)CC FKRCODPIKNYEAC-UHFFFAOYSA-N 0.000 description 2
- NBVXSUQYWXRMNV-UHFFFAOYSA-N fluoromethane Chemical class FC NBVXSUQYWXRMNV-UHFFFAOYSA-N 0.000 description 2
- 229910052744 lithium Inorganic materials 0.000 description 2
- 230000014759 maintenance of location Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- TZIHFWKZFHZASV-UHFFFAOYSA-N methyl formate Chemical compound COC=O TZIHFWKZFHZASV-UHFFFAOYSA-N 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 238000007151 ring opening polymerisation reaction Methods 0.000 description 2
- 238000007086 side reaction Methods 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 125000001273 sulfonato group Chemical class [O-]S(*)(=O)=O 0.000 description 2
- 230000002195 synergetic effect Effects 0.000 description 2
- 238000010998 test method Methods 0.000 description 2
- 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 description 1
- 229910001148 Al-Li alloy Inorganic materials 0.000 description 1
- 229940126062 Compound A Drugs 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 description 1
- 239000002000 Electrolyte additive Substances 0.000 description 1
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 1
- NLDMNSXOCDLTTB-UHFFFAOYSA-N Heterophylliin A Natural products O1C2COC(=O)C3=CC(O)=C(O)C(O)=C3C3=C(O)C(O)=C(O)C=C3C(=O)OC2C(OC(=O)C=2C=C(O)C(O)=C(O)C=2)C(O)C1OC(=O)C1=CC(O)=C(O)C(O)=C1 NLDMNSXOCDLTTB-UHFFFAOYSA-N 0.000 description 1
- JGFBQFKZKSSODQ-UHFFFAOYSA-N Isothiocyanatocyclopropane Chemical compound S=C=NC1CC1 JGFBQFKZKSSODQ-UHFFFAOYSA-N 0.000 description 1
- 229910012820 LiCoO Inorganic materials 0.000 description 1
- 229910010710 LiFePO Inorganic materials 0.000 description 1
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 1
- 239000002033 PVDF binder Substances 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 229910001128 Sn alloy Inorganic materials 0.000 description 1
- 229910020923 Sn-O Inorganic materials 0.000 description 1
- 229910010248 TiO2—Li4Ti5O12 Inorganic materials 0.000 description 1
- SOXUFMZTHZXOGC-UHFFFAOYSA-N [Li].[Mn].[Co].[Ni] Chemical compound [Li].[Mn].[Co].[Ni] SOXUFMZTHZXOGC-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
- 239000011149 active material Substances 0.000 description 1
- 239000013543 active substance Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- PWLNAUNEAKQYLH-UHFFFAOYSA-N butyric acid octyl ester Natural products CCCCCCCCOC(=O)CCC PWLNAUNEAKQYLH-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000001768 carboxy methyl cellulose Substances 0.000 description 1
- 239000006182 cathode active material Substances 0.000 description 1
- 239000010406 cathode material Substances 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- QHGJSLXSVXVKHZ-UHFFFAOYSA-N dilithium;dioxido(dioxo)manganese Chemical compound [Li+].[Li+].[O-][Mn]([O-])(=O)=O QHGJSLXSVXVKHZ-UHFFFAOYSA-N 0.000 description 1
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000011883 electrode binding agent Substances 0.000 description 1
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 229910021385 hard carbon Inorganic materials 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 1
- 239000002931 mesocarbon microbead Substances 0.000 description 1
- 239000011325 microbead Substances 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- UUIQMZJEGPQKFD-UHFFFAOYSA-N n-butyric acid methyl ester Natural products CCCC(=O)OC UUIQMZJEGPQKFD-UHFFFAOYSA-N 0.000 description 1
- 229910021382 natural graphite Inorganic materials 0.000 description 1
- 150000002825 nitriles Chemical class 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 description 1
- 238000010298 pulverizing process Methods 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 239000002210 silicon-based material Substances 0.000 description 1
- 239000002153 silicon-carbon composite material Substances 0.000 description 1
- 238000009751 slip forming Methods 0.000 description 1
- 235000019812 sodium carboxymethyl cellulose Nutrition 0.000 description 1
- 229920001027 sodium carboxymethylcellulose Polymers 0.000 description 1
- 229910021384 soft carbon Inorganic materials 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 1
- 239000002562 thickening agent Substances 0.000 description 1
- 238000009461 vacuum packaging Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 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
- H01M2300/0017—Non-aqueous electrolytes
- H01M2300/0025—Organic electrolyte
-
- 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 invention discloses a non-aqueous electrolyte and a lithium ion battery thereof, wherein the non-aqueous electrolyte comprises lithium salt, a non-aqueous organic solvent and an additive, the additive comprises an additive A, and the additive A accounts for 0.5-10% of the total amount of the non-aqueous electrolyte in percentage by mass; the structural formula of the additive A is as follows:
wherein R is 1 、R 2 Each independently is an unsubstituted C1-C20 alkyl group selected from the group consisting of C1-C20 alkyl substituted by halogen, C3-C20 cycloalkyl substituted by halogen, unsubstituted C3-C20 cycloalkyl phenyl substituted by halogen, unsubstituted phenyl, biphenyl substituted by halogen, unsubstituted biphenyl, C6-C26 phenylalkyl substituted by halogen,Unsubstituted C6-C26 phenylalkyl, C6-C26 condensed ring aromatic hydrocarbon group substituted by halogen, unsubstituted C6-C26 condensed ring aromatic hydrocarbon group or empty bond.
Description
Technical Field
The invention relates to the technical field of lithium ion battery electrolyte, in particular to a non-aqueous electrolyte and a lithium ion battery thereof.
Background
The negative electrode material is a very important component of a lithium ion battery. At present, the theoretical specific capacity of the traditional graphite negative electrode material is 372mAh/g, the capacity of the practical application material can reach more than 360mAh/g, and almost no improvement space exists; compared with the prior art, silicon has extremely high specific mass capacity (4200 mAh/g), which is more than 10 times of that of graphite cathode materials, and the theoretical capacity of silicon oxide is more than 1400mAh, so that the use of high-performance silicon-based materials as cathode active materials is one of the most promising routes for increasing the energy density of batteries. However, the silicon-based electrode can cause huge volume expansion during charging and discharging, leading to pulverization and peeling, and leading to the loss of electric contact between active substances and current collectors thereof. In addition, new SEI films are continuously formed during the powdering process, further resulting in a lower cycle life of the battery.
For a silicon-carbon negative electrode, FEC (fluoroethylene carbonate) is the most common electrolyte additive, and a more stable SEI film can be formed by adding FEC into an electrolyte, so that the cycle life of the silicon-carbon negative electrode is effectively prolonged. However, research shows that when the FEC concentration is insufficient in the circulation process, the cycle life of the silicon-carbon cathode suddenly jumps, so that the FEC content in the electrolyte is required to be at least more than 10%, but an excessively high FEC content causes the gas generation problem of the battery to be aggravated, and also causes the cycle life of the battery to be shortened. In order to solve the problem of gas generation of the battery caused by over-high FEC concentration,
therefore, it is very important to develop an electrolyte suitable for a silicon-carbon negative electrode system, which can form a dense and stable SEI film on the surface of a silicon-carbon negative electrode material and improve the cycle stability of a lithium ion battery.
Disclosure of Invention
The invention aims to provide a non-aqueous electrolyte and a lithium ion battery thereof, which are suitable for a silicon-carbon negative electrode system, can form a compact and stable SEI film on the surface of a silicon-carbon negative electrode material, and improve the cycle stability of the lithium ion battery.
The invention discloses a non-aqueous electrolyte, which comprises a lithium salt, a non-aqueous organic solvent and an additive, wherein the additive comprises an additive A, and the additive A accounts for 0.5-10% of the total amount of the non-aqueous electrolyte in percentage by mass; the structural formula of the additive A is as follows:
wherein R1 and R2 are respectively and independently selected from C1-C20 alkyl substituted by halogen, unsubstituted C1-C20 alkyl, C3-C20 cycloalkyl substituted by halogen, unsubstituted C3-C20 cycloalkyl, phenyl substituted by halogen, unsubstituted phenyl, biphenyl substituted by halogen, unsubstituted biphenyl, C6-C26 phenylalkyl substituted by halogen, unsubstituted C6-C26 phenylalkyl, C6-C26 condensed ring aromatic hydrocarbon substituted by halogen, unsubstituted C6-C26 condensed ring aromatic hydrocarbon or vacant bond.
Optionally, the additive further comprises sulfonate compounds, fluorocarbon esters, and nitrile compounds.
Optionally, the sulfonate compound, the fluorocarbon ester and the nitrile compound respectively account for 3%, 0% -10% and 4% of the total amount of the nonaqueous electrolytic solution in percentage by mass.
Alternatively, the nitrile compounds include succinonitrile, adiponitrile, and 1,3,6-hexanetrinitrile, in mass percent; succinonitrile, adiponitrile and 1,3,6-hexanetricarbonitrile account for 1%, 1% and 2% of the total amount of the nonaqueous electrolytic solution, respectively.
Optionally, the nonaqueous organic solvent accounts for 65-70% of the total amount of the nonaqueous electrolyte, and the lithium salt accounts for 10-20% of the total amount of the nonaqueous electrolyte.
Optionally, the lithium salt is selected from at least one of an organic lithium salt or an inorganic lithium salt.
Optionally, the electrolyte lithium salt is selected from at least one of compounds containing a fluorine element and a lithium element.
Optionally, the electrolyte lithium salt concentration is between 0.5M and 1.5M.
Optionally, the lithium salt concentration is between 0.8M and 1.3M.
The invention also discloses a lithium ion battery which comprises the non-aqueous electrolyte.
The non-aqueous electrolyte of the invention can equally replace FEC in the electrolyte by adding 0.5-10% of additive A, and the action mechanism is as follows: N-CA (carboxylic anhydride compound containing N) generates CO2 removal and ring opening polymerization reaction on the surface of the negative electrode, and the generated a-amino acid can generate polypeptide polymer, so that the two SEI forming mechanisms are in synergistic effect: i.e., the inorganic CO2 and the organic polypeptide, thus forming an effective composite SEI layer. Wherein SEI formed in the removed CO2 atmosphere is thinner, the content of LiF and PEO (polyethylene oxide) is higher, the surface is electronically insulated, and the cycle performance and the coulombic efficiency of the silicon-carbon cathode are improved to a certain extent by reducing the occurrence of side reactions
Detailed Description
It is to be understood that the terminology, the specific structural and functional details disclosed herein are for the purpose of describing particular embodiments only, and are not intended to be limiting, since the present invention may be embodied in many alternate forms and should not be construed as limited to only the embodiments set forth herein.
The invention is described in detail below with reference to alternative embodiments.
The invention discloses a non-aqueous electrolyte, which comprises a lithium salt, a non-aqueous organic solvent and an additive, wherein the additive comprises an additive A, and the additive A accounts for 0.5-10% of the total weight of the non-aqueous electrolyte in percentage by mass; the structural formula of the additive A is as follows:
wherein R is 1 、R 2 Each independently is an unsubstituted C1-C20 alkyl group selected from C1-C20 alkyl group substituted by halogen, C3-C20 cycloalkyl group substituted by halogen, unsubstituted C3-C20 cycloalkyl group, C3-C20 substituted by halogenHalogen-substituted phenyl, unsubstituted phenyl, biphenyl substituted by halogen, unsubstituted biphenyl, C6-C26 phenylalkyl substituted by halogen, unsubstituted C6-C26 phenylalkyl, C6-C26 fused ring aromatic hydrocarbon substituted by halogen, unsubstituted C6-C26 fused ring aromatic hydrocarbon or a vacant bond.
The non-aqueous electrolyte of the invention can equally replace FEC in the electrolyte by adding 0.5-10% of additive A, and the action mechanism is as follows: N-CA (carboxylic anhydride compound containing N) generates CO2 removal and ring opening polymerization reaction on the surface of the negative electrode, and the generated a-amino acid can generate polypeptide polymer, so that the two SEI forming mechanisms are in synergistic effect: i.e., the inorganic CO2 and the organic polypeptide, thus forming an effective composite SEI layer. Wherein SEI formed in the removed CO2 atmosphere is thinner, the contents of LiF and PEO (polyethylene oxide) are higher, the surface is electronically insulated, and the cycle performance and the coulombic efficiency of the silicon-carbon cathode are improved to a certain extent by reducing the occurrence of side reactions.
Specifically, the additive a may be 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%. Preferably, additive a is 2%.
Specifically, the additives also include sulfonate compounds, fluorocarbon esters, and nitrile compounds. The sulfonic acid ester compound, the fluorocarbon ester and the nitrile compound can further improve the cycle performance of the non-aqueous electrolyte and improve gas generation. Specifically, the sulfonate compound, the fluorocarbon ester and the nitrile compound account for 3%, 0% -10% and 4% of the total amount of the nonaqueous electrolytic solution by mass percent, respectively. The fluorocarbon ester can be 0%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%. The sulfonate compound may be 1,3-Propane Sultone (PS) and the fluorocarbon ester may be fluoroethylene carbonate (FEC).
Specifically, the nitrile compounds include Succinonitrile (SN), adiponitrile (ADN), and 1,3,6-Hexanetricarbonitrile (HTCN); succinonitrile, adiponitrile and 1,3,6-hexanetricarbonitrile account for 1%, 1% and 2% of the total amount of the nonaqueous electrolytic solution, respectively.
Specifically, the nonaqueous organic solvent accounts for 65-70% of the total amount of the nonaqueous electrolyte, and the lithium salt accounts for 10-20% of the total amount of the nonaqueous electrolyte. The non-aqueous organic solvent may be 65%, 66%, 67%, 68%, 69%, 70%. The lithium salt may be 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%.
Specifically, the lithium salt is selected from at least one of organic lithium salt or inorganic lithium salt.
Specifically, the electrolyte lithium salt is at least one selected from compounds containing a fluorine element and a lithium element.
Specifically, the electrolyte lithium salt concentration is 0.5M to 1.5M. The concentration of the lithium salt is too low, the conductivity of the electrolyte is low, and the multiplying power and the cycle performance of the whole battery system can be influenced; the lithium salt concentration is too high, the viscosity of the electrolyte is too high, and the multiplying power of the whole battery system is also influenced. Specifically, the concentration of the lithium salt is 0.8M to 1.3M. The lithium salt concentration may be 0.8M, 0.9M, 1M, 1.1M, 1.2M, 1.3M, 1.4M, 1.5M.
Specifically, the non-aqueous organic solvent is at least two selected from ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl formate, ethyl propionate, propyl propionate, methyl butyrate and tetrahydrofuran.
The invention also discloses a lithium ion battery which comprises the non-aqueous electrolyte.
The lithium ion battery also comprises a positive plate, a negative plate and a lithium battery diaphragm. The positive plate comprises a positive current collector and a positive active slurry layer positioned on the positive current collector. Wherein the positive active slurry layer comprises a positive active material; the negative plate comprises a negative current collector and a negative active slurry layer positioned on the negative current collector. The negative active paste layer includes a negative active material. The specific types of the positive electrode active material, the positive electrode binder and the negative electrode active material are not particularly limited and can be selected according to requirements.
The positive electrode active material is selected from lithium cobaltate (LiCoO) 2 ) Lithium nickel manganese cobalt ternary material, lithium iron phosphate (LiFePO) 4 ) Lithium manganate (LiMn) 2 O 4 ) One or more of (a).
The negative active material is graphite and/or silicon, e.g. natural graphite, artificial graphiteGraphite, mesophase carbon microbeads (MCMB for short), hard carbon, soft carbon, silicon-carbon composite, li-Sn alloy, li-Sn-O alloy, sn, snO 2 Spinel-structured lithiated TiO 2 -Li 4 Ti 5 O 12 And Li-Al alloy can be used as the active material of the negative electrode.
The present application is illustrated by the following specific examples.
Example 1
Preparation of the electrolyte
The preparation method of the electrolyte comprises the following steps: EC/PC/DEC/PP was mixed as a nonaqueous organic solvent in the following ratio of Table 1. Adding additives PS, FEC and nitrile compounds SN, ADN and HTCN into a non-aqueous organic solvent, uniformly mixing, and adding LiPF 6 Obtaining LiPF 6 The mixed solution with the concentration of 1.1mol/L is added with the compound A, PS is 1,3-propane sultone, FEC is fluoroethylene carbonate, SN is succinonitrile, ADN is adiponitrile, and HTCN is 1,3,6 hexane trinitrile. The proportions of the components are shown in Table 1. The specific additive A has the following structural formula:
manufacture of batteries
Manufacturing a positive plate: the positive electrode active material LCO, the conductive agent CNT, and the binder polyvinylidene fluoride were sufficiently stirred and mixed in an N-methylpyrrolidone solvent in a weight ratio of 97. And coating the slurry on an Al foil of a positive current collector, drying and cold pressing to obtain the positive plate.
And (3) manufacturing a negative plate: fully stirring and mixing graphite as a negative electrode active material, silicon carbon, acetylene black as a conductive agent, styrene butadiene rubber as a binder and sodium carboxymethyl cellulose as a thickening agent in a proper amount of deionized water solvent according to a mass ratio of 95. And coating the slurry on a Cu foil of a negative current collector, drying and cold pressing to obtain a negative pole piece.
Manufacturing the lithium ion battery: the positive pole piece, the isolating membrane and the negative pole piece are sequentially stacked, so that the isolating membrane is positioned between the positive pole and the negative pole, the isolating effect is achieved, and then the bare cell can be wound. And (3) placing the bare cell into an outer packaging bag, respectively injecting the electrolyte in the table 1 into the dried battery, and performing vacuum packaging, standing, formation, shaping and other processes to complete the preparation of the lithium ion battery.
High temperature cycle testing of the battery: the test method comprises the following steps: and (3) placing the battery in an environment of 45 +/-2 ℃, and calculating the capacity retention rate of the battery after circulation according to the standard charge-discharge circulation, the circulation multiplying power of 1C and the charging voltage of 3.0-4.5V. The calculation formula is as follows: the nth cycle capacity retention ratio (%) = (nth cycle discharge capacity)/(first cycle discharge capacity) × 100%.
High temperature storage test of the battery: the test method comprises the following steps: and (3) charging the partial-volume battery cell to 4.5V at the normal temperature by 0.5C, placing the fully-charged battery in an environment of 85 ℃ for 6 hours, measuring the thickness expansion rate by heat, discharging to 3.0V by 0.5C after the room temperature is recovered, and recording the discharge capacity.
Examples 2 to 6
Examples 2 to 6 differ from example 1 only in the amount of a part of the components added, as shown in Table 1.
Comparative example 1
Comparative example 1 differs from example 1 only in the amount of FEC added, and no additive a was added.
TABLE 1
The test cases of the respective examples and comparative examples are shown in Table 2.
TABLE 2
As can be seen from examples 1 to 6 and comparative example 1 in Table 2, the high temperature cycle and safety performance results of example 3 are the best, i.e., the additive A is added at a 2% level for best results. The equivalent replacement of 2% wt of FEC by additive A significantly improved gassing and capacity fade.
The foregoing is a more detailed description of the invention in connection with specific alternative embodiments, and the practice of the invention should not be construed as limited to those descriptions. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.
Claims (10)
1. The nonaqueous electrolyte is characterized by comprising a lithium salt, a nonaqueous organic solvent and an additive, wherein the additive comprises an additive A, and the additive A accounts for 0.5-10% of the total amount of the nonaqueous electrolyte in percentage by mass; the structural formula of the additive A is as follows:
wherein R is 1 、R 2 Each independently is an unsubstituted C1-C20 alkyl group, a C3-C20 cycloalkyl group substituted by halogen, an unsubstituted C3-C20 cycloalkyl group, a phenyl group substituted by halogen, an unsubstituted phenyl group, a biphenyl group substituted by halogen, an unsubstituted biphenyl group, a C6-C26 phenylalkyl group substituted by halogen, an unsubstituted C6-C26 phenylalkyl group, a C6-C26 fused ring aromatic hydrocarbon group substituted by halogen, an unsubstituted C6-C26 fused ring aromatic hydrocarbon group or an empty bond selected from the group consisting of C1-C20 alkyl groups substituted by halogen.
2. The nonaqueous electrolytic solution of claim 1, wherein the additive further comprises a sulfonate compound, a fluorocarbon ester, and a nitrile compound.
3. The nonaqueous electrolytic solution of claim 2, wherein the sulfonate compound, the fluorocarbon ester and the nitrile compound are respectively 3%, 0% to 10% and 4% by mass of the total amount of the nonaqueous electrolytic solution.
4. The nonaqueous electrolytic solution of claim 3, wherein the nitrile compounds include, in mass percent, succinonitrile, adiponitrile, and 1,3,6-hexanetricarbonitrile; the succinonitrile, adiponitrile and 1,3,6-hexanetricarbonitrile account for 1%, 1% and 2% of the total amount of the nonaqueous electrolytic solution, respectively.
5. The nonaqueous electrolyte solution of claim 1, wherein the nonaqueous organic solvent accounts for 65% to 70% of the total amount of the nonaqueous electrolyte solution, and the lithium salt accounts for 10% to 20% of the total amount of the nonaqueous electrolyte solution in percentage by mass.
6. The nonaqueous electrolytic solution of claim 1, wherein the lithium salt is selected from at least one of an organic lithium salt and an inorganic lithium salt.
7. The nonaqueous electrolytic solution of claim 1, wherein the electrolytic lithium salt is at least one selected from compounds containing a fluorine element and a lithium element.
8. The nonaqueous electrolytic solution of claim 1, wherein the electrolyte lithium salt concentration is 0.5M to 1.5M.
9. The nonaqueous electrolytic solution of claim 8, wherein the lithium salt concentration is 0.8M to 1.3M.
10. A lithium ion battery comprising the nonaqueous electrolytic solution according to any one of claims 1 to 9.
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