CN109216759B - Lithium ion battery electrolyte and lithium ion battery - Google Patents

Lithium ion battery electrolyte and lithium ion battery Download PDF

Info

Publication number
CN109216759B
CN109216759B CN201811071593.5A CN201811071593A CN109216759B CN 109216759 B CN109216759 B CN 109216759B CN 201811071593 A CN201811071593 A CN 201811071593A CN 109216759 B CN109216759 B CN 109216759B
Authority
CN
China
Prior art keywords
ion battery
lithium ion
lithium
electrolyte
carbonate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201811071593.5A
Other languages
Chinese (zh)
Other versions
CN109216759A (en
Inventor
刘强
杨攀
谢青松
杨文峰
黄贵祥
高学友
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ZHANJIANG JUXIN NEW ENERGY CO Ltd
Original Assignee
Zhanjiang Jincancan Technology Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Zhanjiang Jincancan Technology Co ltd filed Critical Zhanjiang Jincancan Technology Co ltd
Priority to CN201811071593.5A priority Critical patent/CN109216759B/en
Publication of CN109216759A publication Critical patent/CN109216759A/en
Application granted granted Critical
Publication of CN109216759B publication Critical patent/CN109216759B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

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
    • 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)
  • Materials Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Inorganic Chemistry (AREA)
  • Secondary Cells (AREA)

Abstract

The invention discloses a lithium ion battery electrolyte and a lithium ion battery, wherein the lithium ion battery electrolyte comprises a non-aqueous organic solvent, lithium salt and an additive, wherein the additive comprises dicyclohexylcarbodiimide, amino compounds and isocyanate compounds. According to the technical scheme provided by the invention, the additive of the lithium ion battery electrolyte comprises dicyclohexylcarbodiimide, amino compounds and isocyanate compounds, wherein the dicyclohexylcarbodiimide assists the amino compounds and the isocyanate compounds to participate in film formation, and a chain or net high polymer film which is insoluble in the electrolyte, strong in oxidation resistance and good in toughness is formed on the surfaces of a positive electrode and a negative electrode of the lithium ion battery, so that the impedance of the battery is reduced, and the high-temperature cycle performance and the rate capability of the lithium ion battery are improved.

Description

Lithium ion battery electrolyte and lithium ion battery
Technical Field
The invention relates to the technical field of lithium ion batteries, in particular to a lithium ion battery electrolyte and a lithium ion battery.
Background
Along with the development of society and the improvement of science and technology, people have higher and higher requirements on the unit volume capacity of lithium ion batteries, a series of novel high-specific-capacity anode materials such as modified lithium cobaltate, high-nickel ternary, lithium-rich manganese and the like are produced at the same time, the specific capacity is high along with the high working voltage of the batteries, and the working voltage of the batteries is more than or equal to 4.35V and even reaches 4.8V. While conventional film-decorating additives VC (vinylene carbonate) and PS (1,3-propane sultone) are unstable in film formation under the condition of high voltage of more than or equal to 4.35V, an SEI (solid electrolyte interface) in the lithium ion battery, namely, a passivation layer covering the surface of an electrode material and formed by the reaction of the electrode material and an electrolyte on a solid-liquid phase interface in the first charge-discharge process of the liquid lithium ion battery can effectively prevent solvent molecules from passing through, but lithium ions can be freely inserted and extracted through the passivation layer) can crack and fall due to the generation of gas to expose active sites of the anode material, and electrolyte components including lithium salt, the solvent and the additives can react on the active sites of the anode material to reduce the capacity of the battery, the resistance increases and the cycle performance is further deteriorated, and the high temperature operation environment of the battery also aggravates the deterioration.
In order to improve the energy density of the whole unit volume of the battery, the negative electrode of the lithium ion battery also needs to have high unit gram capacity, and the silicon-carbon composite negative electrode material is a hot spot of the current research. The theoretical specific capacity of the silicon negative electrode material is 3572mAh/g, and the silicon negative electrode material has the advantages of high specific capacity, low working voltage, rich reserve and the like, but the silicon has the transformation of a crystal phase in the lithium extraction process and is accompanied with violent volume change (more than 300 percent), so that particles are crushed to cause poor cycle stability, and the silicon negative electrode material is often used in a composite way with carbon. The silicon-carbon composite material has better stability than pure silicon, but the volume effect of the silicon-carbon composite material in the circulating process is gradually obvious as the unit gram capacity is increased along with the increase of the silicon content, the repeated contraction and expansion leads the surface film of the electrode to be cracked and regenerated, and lithium salt and solvent are continuously consumed, thereby reducing the high-temperature circulating performance and the rate capability of the lithium ion battery.
Disclosure of Invention
The invention mainly aims to provide a lithium ion battery electrolyte and a lithium ion battery, and aims to improve the high-temperature cycle performance and the rate capability of the lithium ion battery.
In order to achieve the purpose, the invention provides a lithium ion battery electrolyte, which comprises a non-aqueous organic solvent, a lithium salt and an additive, wherein the additive comprises dicyclohexylcarbodiimide, an amino compound and an isocyanate compound.
Preferably, the addition amount of the dicyclohexylcarbodiimide is 0.05-0.15% of the total mass of the lithium ion battery electrolyte;
the addition amount of the amino compound is 0.2-1.0% of the total mass of the lithium ion battery electrolyte;
the addition amount of the isocyanate compound is 1.0-2.0% of the total mass of the lithium ion battery electrolyte.
Preferably, the amino compound is a compound having a structure represented by structural formula (1):
Figure BDA0001798962570000021
wherein R is1Comprises at least one of alkyl, phenyl and substitute thereof and s-triazinyl; and/or the presence of a gas in the gas,
the isocyanate compound is a compound having a structure represented by a structural formula (2):
Figure BDA0001798962570000022
wherein R is2Is one or two of alkyl, phenyl and substitutes thereof, and n is 1, 2 or 3.
Preferably, the amino compound is at least one of the compounds having the structures shown by the structural formulas of the following compounds B1 to B8:
Figure BDA0001798962570000031
preferably, the isocyanate compound is at least one of compounds having the structures shown by the structural formulae of the following compounds a1 to a compound a 9:
Figure BDA0001798962570000032
preferably, the addition amount of the non-aqueous organic solvent is 68-85% of the total mass of the lithium ion battery electrolyte;
the addition amount of the lithium salt is 8-15% of the total mass of the lithium ion battery electrolyte;
the additive also comprises fluoroethylene carbonate, vinylene carbonate and 1,3-propane sultone, and the additive of fluoroethylene carbonate, vinylene carbonate and 1,3-propane sultone corresponds to 5-12%, 0.1-1.0% and 0.1-1.0% of the total mass of the lithium ion battery electrolyte.
Preferably, the addition amount of the non-aqueous organic solvent is 68-75% of the total mass of the lithium ion battery electrolyte;
the addition amount of the lithium salt is 10-15% of the total mass of the lithium ion battery electrolyte.
Preferably, the non-aqueous organic solvent comprises a mixture of two or three of ethylene carbonate, dimethyl carbonate, propylene carbonate, butylene carbonate, gamma-butyrolactone, methyl propyl carbonate, ethyl propyl carbonate, propyl acetate, ethyl propionate, propyl propionate, diethyl carbonate and methyl ethyl carbonate; and/or the presence of a gas in the gas,
the lithium salt comprises lithium bis (oxalato) borate, lithium bis (trifluoromethylsulfonyl) imide, lithium tetrafluoroborate, lithium bis (fluorosulfonato) imide, lithium difluorooxalato borate, lithium difluorophosphate, lithium difluorooxalato phosphate and a mixture of lithium tetrafluorooxalato phosphate and lithium hexafluorophosphate.
In order to achieve the above object, the present invention further provides a lithium ion battery, which includes a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and an electrolyte filled in the positive electrode and the negative electrode, wherein the electrolyte is the above lithium ion battery electrolyte.
Preferably, the active material of the positive electrode is LiNixCoyMnzM1-x-y-zO2Or LiNixCoyAlzM1-x-y-zO2Wherein M is any one of Co, Ni, Mn, Mg, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V and Ti, y is more than or equal to 0 and less than or equal to 1, x is more than or equal to 0 and less than 1, z is more than or equal to 0 and less than or equal to 1, and x + y + z is less than or equal to 1; and/or the presence of a gas in the gas,
the active material of the negative electrode is a silicon-carbon composite material.
According to the technical scheme provided by the invention, the additive of the lithium ion battery electrolyte comprises dicyclohexylcarbodiimide, amino compounds and isocyanate compounds, wherein the dicyclohexylcarbodiimide assists the amino compounds and the isocyanate compounds to participate in film formation, and a chain or net high polymer film which is insoluble in the electrolyte, strong in oxidation resistance and good in toughness is formed on the surfaces of a positive electrode and a negative electrode of the lithium ion battery, so that the impedance of the battery is reduced, and the high-temperature cycle performance and the rate capability of the lithium ion battery are improved.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
The invention provides a lithium ion battery electrolyte, which aims to solve the problem that the high-temperature cycle performance and the rate capability of the existing lithium ion battery are poor, and comprises a non-aqueous organic solvent, a lithium salt and an additive, wherein the additive comprises Dicyclohexylcarbodiimide (DCC), an amino compound and an isocyanate compound.
When the lithium ion battery electrolyte provided by the invention is applied to a lithium ion battery, for example, when the lithium ion battery is a lithium ion battery taking a silicon-carbon composite material as a negative active material, the components in the additive play the following roles: DCC is mainly used for removing trace moisture and acid in the electrolyte and inhibiting the decomposition of isocyanate compounds; the amino compound and the isocyanate compound react to generate a chain or net high polymer film which is insoluble in electrolyte, strong in oxidation resistance and good in toughness when the lithium ion battery is formed and aged, the chain or net high polymer film is covered on the surface of an active material, a solvent in the electrolyte can be prevented from contacting with the active material on an anode, and a cathode can be wrapped and reinforced with an SEI (solid electrolyte interface) film, namely, the SEI film is a passivation layer which is formed by the reaction of an electrode material and the electrolyte on a solid-liquid phase interface and covers the surface of the electrode material in the first charge-discharge process of the liquid lithium ion battery, so that the passing of solvent molecules can be effectively prevented, but lithium ions can be freely inserted and extracted through the passivation layer, and the shedding of the SEI film in the repeated shrinkage and expansion of the silicon-carbon composite cathode material is inhibited; meanwhile, the thickness of an interfacial film between the active substance and the electrolyte is reduced by covering the high-molecular polymer film, so that the impedance of the battery is reduced, and the high-temperature performance, the rate capability and the cycle performance of the high-voltage lithium ion battery are improved.
According to the technical scheme provided by the invention, the additive of the lithium ion battery electrolyte comprises DCC, amino compounds and isocyanate compounds, wherein the DCC assists the amino compounds and the isocyanate compounds to participate in film formation, and a chain or net-shaped high polymer film which is insoluble in the electrolyte, strong in oxidation resistance and good in toughness is formed on the surfaces of a positive electrode and a negative electrode of the lithium ion battery, so that the impedance of the battery is reduced, and the high-temperature cycle performance and the rate capability of the lithium ion battery are improved.
In an embodiment of the lithium ion battery electrolyte provided by the invention, the addition amount of the dicyclohexylcarbodiimide is 0.05-0.15% of the total mass of the lithium ion battery electrolyte; the addition amount of the amino compound is 0.2-1.0% of the total mass of the lithium ion battery electrolyte; the addition amount of the isocyanate compound is 1.0-2.0% of the total mass of the lithium ion battery electrolyte.
In this embodiment, the amino compound is a compound having a structure represented by structural formula (1):
Figure BDA0001798962570000061
wherein R is1Including at least one of alkyl, phenyl and its substitute and s-triazinyl, may be used as the amino compound in the embodiments of the present invention.
Further, the compound having the structure represented by the structural formula (1) as described above (i.e., the amino-based compound) may be selected from at least one of the following compounds having the structures represented by the structural formulae of compound B1 to compound B8:
Figure BDA0001798962570000062
the compound may be any one of the compounds B1 to B8, or a mixture of any two or more of the compounds B1 to B8.
In this embodiment, the isocyanate compound may be selected from a monoisocyanate compound, a diisocyanate compound, or a polyisocyanate compound, and more preferably a compound having a structure represented by structural formula (2):
Figure BDA0001798962570000063
wherein R is2One or two of alkyl, phenyl and substitutes thereof, and n is 1, 2 or 3, can be used as the isocyanate compound in the embodiment of the invention.
Further, the compound having the structure represented by the structural formula (2) as described above (i.e., the isocyanate-based compound) may be selected from at least one of the following compounds having the structures represented by the structural formulae of compound a1 to compound a 9:
Figure BDA0001798962570000071
the compound may be any one of the compounds a1 to a9, or a mixture of any two or more of the compounds a1 to a 9.
Optionally, in this embodiment, the addition amount of the non-aqueous organic solvent is 68 to 85% of the total mass of the lithium ion battery electrolyte, and the addition amount of the lithium salt is 8 to 15% of the total mass of the lithium ion battery electrolyte. In another preferred embodiment of the invention, the addition amount of the non-aqueous organic solvent is preferably 68-75% of the total mass of the lithium ion battery electrolyte; the addition amount of the lithium salt is preferably 10-15% of the total mass of the lithium ion battery electrolyte.
In this embodiment, the additive includes a conventional film-forming additive, which is preferably Vinylene Carbonate (VC), 1,3-Propane Sultone (PS), and Fluoroethylene carbonate (FEC), in addition to DCC, an amino compound, and an isocyanate mixture. Wherein the FEC has a lower LUMO (orbital with lowest unoccupied electron energy level is called lowest unoccupied orbital, represented by LUMO) value than the solvent, and is capable of being preferentially dissolved in the solvent to perform a reduction reaction at the negative electrode, thereby forming a stable and flexible SEI film. The VC and the PS have good film-forming property and low-temperature conductivity as additives, can inhibit the decomposition of FEC, and improve the capacity loss of the lithium ion battery during the first charge and discharge, thereby being beneficial to improving the reversible capacity of the lithium ion battery and further improving the long-term cycle performance of the lithium ion battery. Furthermore, the addition amounts of the FEC, the VC and the PS correspond to 5-12%, 0.1-1.0% and 0.1-1.0% of the total mass of the electrolyte.
For lithium ion batteries, the operating voltage of the battery is much higher than the decomposition voltage of water, so the electrolyte is usually prepared by using a non-aqueous organic solvent such as diethyl ether, ethylene carbonate, propylene carbonate and diethyl carbonate, and meanwhile, using a lithium salt as a solute such as lithium perchlorate, lithium hexafluorophosphate and lithium tetrafluoroborate, mixing the lithium salt with the non-aqueous organic solvent to prepare a basic stock solution for preparing the electrolyte, and then adding additives such as a film-forming agent to prepare the electrolyte of the lithium ion battery. In an embodiment of the present invention, the non-aqueous organic solvent includes a mixture of two or three of ethylene carbonate, dimethyl carbonate, propylene carbonate, butylene carbonate, γ -butyrolactone, methyl propyl carbonate, ethyl propyl carbonate, propyl acetate, ethyl propionate, propyl propionate, diethyl carbonate, and methyl ethyl carbonate; and/or the lithium salt comprises lithium bis (oxalato) borate, lithium bis (trifluoromethylsulfonyl) imide, lithium tetrafluoroborate, lithium bis (fluorosulfonato) imide, lithium difluorooxalato borate, lithium difluorophosphate, lithium difluorooxalato phosphate and a mixture of lithium tetrafluorooxalato phosphate and lithium hexafluorophosphate.
The invention further provides a lithium ion battery, which comprises an anode, a cathode, a diaphragm arranged between the anode and the cathode, and electrolyte filled in the anode and the cathode, wherein the electrolyte is the lithium ion battery electrolyte, and the lithium ion battery electrolyte is applied to the lithium ion battery taking a high-nickel material as the anode and a silicon-carbon composite material as the cathode, so that the high-temperature cycle performance and the rate capability of the lithium ion battery are improved more obviously.
In bookIn an embodiment of the lithium ion battery, an active material of a positive electrode of the lithium ion battery is LiNixCoyMnzM1-x-y-zO2Or LiNixCoyAlzM1-x-y-zO2Wherein M is any one of Co, Ni, Mn, Mg, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V and Ti, y is more than or equal to 0 and less than or equal to 1, x is more than or equal to 0 and less than 1, z is more than or equal to 0 and less than or equal to 1, and x + y + z is less than or equal to 1; and/or the active material of the negative electrode is a silicon-carbon composite material, and has the advantages of high capacity, low cost, rich sources and the like; the separator is generally a polyolefin porous film having a porous structure and resistant to a nonaqueous organic solvent, such as a polyolefin microporous film of polyethylene (prepared by a wet process), polypropylene (prepared by a dry process), and the like. The positive electrode active material of the lithium ion battery is nickel cobalt lithium aluminate (NCA, LiNi)0.8Co0.15Al0.05O2) And preparing and testing the lithium ion battery by taking the polyolefin porous membrane prepared by the wet method as an example of the diaphragm of the lithium ion battery.
The technical solutions of the present invention are further described in detail with reference to the following specific examples, which should be understood as merely illustrative and not limitative.
Example 1
(1) Preparing a positive electrode: high voltage positive electrode active material NCA (nickel cobalt aluminum ternary material LiNi)0.8Co0.1Mn0.1O2Obtained from BTR), CNTs (carbon nanotubes) and PVDF (polyvinylidene fluoride) in a mass ratio of 97.8: 1.0: 1.2, uniformly mixing, and then dispersing in N-methyl-2-pyrrolidone to obtain anode slurry; and uniformly coating the anode slurry on two sides of the aluminum foil, rolling and cutting to obtain an anode plate, and finally baking and vacuum drying for later use.
(2) Preparing a negative electrode: silicon carbon BTR-S450 negative electrode material (purchased from BTR), acetylene black, CMC (carboxymethyl cellulose), SBR (styrene butadiene rubber) and binder are mixed according to the mass ratio of 95.8: 0.5: 1.4: 1.8: 0.5, uniformly mixing, and then dispersing in deionized water to obtain cathode slurry; and uniformly coating the negative electrode slurry on two surfaces of the copper foil, rolling and cutting to obtain a negative electrode plate, and finally baking and vacuum drying for later use.
(3) Preparing electrolyte: in a nitrogen-filled glove box (O)2＜2ppm，H2O is less than 3ppm), mixing ethylene carbonate, dimethyl carbonate and methyl ethyl carbonate according to the mass ratio of 2: 4: 1, uniformly mixing to prepare a non-aqueous organic solvent; then taking a nonaqueous organic solvent accounting for 75% of the total mass of the electrolyte, and adding 0.5% of VC, 10% of FEC, 0.5% of PS, 1.0% of isocyanate compound A1, 0.5% of amino compound B1 and 0.05% of DCC into the nonaqueous organic solvent to obtain a mixed solution; and slowly adding a mixture of lithium hexafluorophosphate and lithium difluorooxalato borate accounting for 12.45 percent of the total mass of the electrolyte into the mixed solution to prepare a lithium salt solution of which the concentration of the lithium hexafluorophosphate is 1.2mol/L, and uniformly mixing to obtain the electrolyte.
(4) Preparing a lithium ion battery: the preparation method comprises the following steps of sequentially stacking a positive plate, a diaphragm (a polyolefin porous membrane purchased from Asahi science and technology Co., Ltd.) and a negative plate, winding to obtain a naked electric core, packaging by an aluminum-plastic film, baking again, injecting liquid, standing, forming, shaping by a clamp, secondary sealing and testing capacity, and completing the preparation of the lithium ion soft package battery.
Example 2
The preparation method of the lithium ion battery is the same as that of example 1, except that the nonaqueous organic solvent in the step (3) is ethylene carbonate, dimethyl carbonate and ethyl methyl carbonate in a mass ratio of 2: 4: 1, uniformly mixing the mixed solution, wherein the addition amount of the mixed solution is 75 percent of the total mass of the electrolyte; the lithium salt is a mixture of lithium hexafluorophosphate and lithium difluorooxalato borate, and the addition amount of the lithium salt is 12.45 percent of the total mass of the electrolyte; the composition and the addition amount (wt%) of the additive in the total electrolyte are shown in table 1 below.
Table 1 Components to be added in amounts and amounts to be added in examples and comparative examples
Figure BDA0001798962570000101
Figure BDA0001798962570000111
Example 3
The preparation method of the lithium ion battery is the same as that of the example 1, except that the nonaqueous organic solvent in the step (3) is ethylene carbonate, propylene carbonate and butylene carbonate according to the mass ratio of 2: 4: 1, uniformly mixing the mixed solution, wherein the addition amount of the mixed solution is 76.07 percent of the total mass of the electrolyte; the lithium salt is a mixture of lithium hexafluorophosphate and lithium difluorooxalato borate, and the addition amount of the lithium salt is 8 percent of the total mass of the electrolyte; the composition and the addition amount of the additive in percentage by mass of the total electrolyte are shown in table 1.
Example 4
The preparation method of the lithium ion battery is the same as that of example 1, except that the nonaqueous organic solvent in the step (3) is gamma-butyrolactone, methyl propyl carbonate and ethylene propylene carbonate in a mass ratio of 2: 4: 1, uniformly mixing the mixed solution, wherein the addition amount of the mixed solution is 80% of the total mass of the electrolyte; the lithium salt is a mixture of lithium hexafluorophosphate and lithium difluorophosphate, and the addition amount of the lithium salt is 8.7 percent of the total mass of the electrolyte; the composition and the addition amount of the additive in percentage by mass of the total electrolyte are shown in table 1.
Example 5
The preparation method of the lithium ion battery is the same as that of example 1, except that the nonaqueous organic solvent in the step (3) is ethylene carbonate and ethyl propionate in a mass ratio of 1: 1, uniformly mixing the mixed solution, wherein the addition amount of the mixed solution is 68.4 percent of the total mass of the electrolyte; the lithium salt is a mixture of lithium hexafluorophosphate and lithium tetrafluoroborate, and the addition amount of the lithium salt is 14.95 percent of the total mass of the electrolyte; the composition and the addition amount of the additive in percentage by mass of the total electrolyte are shown in table 1.
Example 6
The preparation method of the lithium ion battery is the same as that of example 1, except that the non-aqueous organic solvent in the step (3) is propyl propionate, diethyl carbonate and ethyl methyl carbonate in a mass ratio of 1: 1: 1, uniformly mixing the mixed solution, wherein the addition amount of the mixed solution is 78% of the total mass of the electrolyte; the lithium salt is a mixture of lithium hexafluorophosphate and lithium bis (oxalato) borate, and the addition amount of the lithium salt is 13.22 percent of the total mass of the electrolyte; the composition and the addition amount of the additive in percentage by mass of the total electrolyte are shown in table 1.
Example 7
The preparation method of the lithium ion battery is the same as that of example 1, except that the nonaqueous organic solvent in the step (3) is propyl acetate, propyl propionate and dimethyl carbonate according to the mass ratio of 3: 2: 1, uniformly mixing the mixed solution, wherein the addition amount of the mixed solution is 72 percent of the total mass of the electrolyte; the lithium salt is a mixture of lithium hexafluorophosphate, lithium difluorooxalate phosphate and lithium tetrafluorooxalate phosphate, and the addition amount of the lithium salt is 14.58 percent of the total mass of the electrolyte; the composition and the addition amount of the additive in percentage by mass of the total electrolyte are shown in table 1.
Example 8
The preparation method of the lithium ion battery is the same as that of example 1, except that the nonaqueous organic solvent in the step (3) is ethyl methyl carbonate and ethylene carbonate according to the mass ratio of 2: 1, uniformly mixing the mixed solution, wherein the addition amount of the mixed solution is 77.94 percent of the total mass of the electrolyte; the lithium salt is a mixture of lithium hexafluorophosphate and lithium bis (trifluoromethyl) sulfonyl imide, and the addition amount of the lithium salt is 10 percent of the total mass of the electrolyte; the composition and the addition amount of the additive in percentage by mass of the total electrolyte are shown in table 1.
Example 9
The preparation method of the lithium ion battery is the same as that of example 1, except that the nonaqueous organic solvent in the step (3) is ethyl propyl carbonate, propyl propionate and diethyl carbonate in a mass ratio of 2: 2: 1, uniformly mixing the mixed solution, wherein the addition amount of the mixed solution is 80% of the total mass of the electrolyte; the lithium salt is a mixture of lithium hexafluorophosphate and lithium bis (fluorosulfonyl) imide, and the addition amount of the lithium salt is 12.16% of the total mass of the electrolyte; the composition and the addition amount of the additive in percentage by mass of the total electrolyte are shown in table 1.
Example 10
The preparation method of the lithium ion battery is the same as that of the example 1, except that the nonaqueous organic solvent in the step (3) is dimethyl carbonate and butylene carbonate according to the mass ratio of 3: 1, uniformly mixing the mixed solution, wherein the addition amount of the mixed solution is 70% of the total mass of the electrolyte; the lithium salt is a mixture of lithium difluorosulfonimide, lithium tetrafluoroborate and lithium difluorophosphate, and the addition amount of the lithium salt is 14.93 percent of the total mass of the electrolyte; the composition and the addition amount of the additive in percentage by mass of the total electrolyte are shown in table 1.
Comparative examples 1 to 6
The lithium ion battery was prepared in the same manner as in example 1, except that the components and the additive amount of the additive in step (3) were as shown in table 1 in percentage by mass of the total mass of the electrolyte.
The lithium ion batteries prepared in examples 1 to 10 and comparative examples 1 to 6 were respectively tested for their relevant properties, including normal temperature cycle performance, high temperature storage performance, and rate capability, and the specific test method was as follows:
(1) and (3) testing the normal-temperature cycle performance: at 25 ℃, the formed battery is charged to 4.4V (the cut-off current is 0.01C) by using a 1C constant current and constant voltage, and then is discharged to 3.0V by using a 1C constant current, and the retention rate of the cycle capacity of 300 cycles of charge/discharge is calculated, wherein the calculation formula is as follows:
capacity retention (%) at 300 cycles [% ] 300 cycles discharge capacity/1 st cycles discharge capacity × 100%
(2) And (3) testing the high-temperature storage performance: the formed battery is charged to 4.4V (cutoff current is 0.01C) at 25 ℃ by using a constant current and constant voltage of 0.5C, then is stored at 60 ℃ for 7 days at high temperature, is discharged to 3.0V by using 0.5C, is kept for 5min, and is charged to 4.4V (cutoff current is 0.01C) by using a constant current and constant voltage of 1C to measure the capacity retention rate and the capacity recovery rate of the battery, and the calculation formula is as follows:
battery capacity retention (%) retention capacity/initial capacity × 100%
Battery capacity recovery (%) -recovery capacity/initial capacity X100%
(3) And (3) rate performance test: charging to 4.4V (cutoff current of 0.01C) at 25 deg.C with constant current and constant voltage of 0.2C, standing for 5min, and discharging to 3.0V at 1C; standing for 5min, charging to 4.4V (cutoff current of 0.01C) with 0.5C constant current and constant voltage, standing for 5min, discharging to 3.0V at 0.5C; standing for 5min, charging to 4.4V (cutoff current is 0.01C) with 1C constant current and constant voltage, standing for 5min, discharging to 3.0V at 0.5C; the charge rate performance of the battery was measured.
The results of the performance test of the lithium ion batteries prepared in the above examples 1 to 10 and comparative examples 1 to 6 are shown in table 2.
Table 2 performance test data of lithium ion batteries prepared in each example and comparative example
Figure BDA0001798962570000141
As can be seen from the comparative analysis of tables 1 and 2, the lithium ion batteries prepared in the examples of the present invention have better high temperature performance, rate performance and cycle performance than the comparative examples, and the further analysis is as follows: in example 1 and comparative examples 1 to 3, the lithium ion battery prepared in comparative example 1 without any additive generally had low high temperature performance, rate performance and cycle performance, and comparative examples 1 and 2 show that the amino compound and the isocyanate compound formed a film on the surface of the electrode, inhibiting deterioration of the battery performance to some extent; the embodiment 1, the comparative example 2 and the comparative example 3 show that the combination of the amino compound and the isocyanate compound can effectively improve the film forming stability of the traditional film decorating additives VC, FEC and PS and improve the high-temperature high-voltage cycle performance of the battery, and the combination of the amino compound and the isocyanate compound can also inhibit the flatulence of the lithium ion battery from the experimental phenomenon, which shows that the film modified by the VC, FEC and PS additives has certain conductivity (electron conduction) at high temperature and high voltage, and the addition of the amino compound and the isocyanate compound changes the components of the film and greatly reduces the conductivity.
In example 1, comparative example 4 and comparative example 5, the cycle performance and rate performance of the battery were decreased with the increase in the addition amount of the amino-based compound and the isocyanate-based compound, indicating that the increase in the addition amount of both increases the internal resistance of the battery and decreases the ionic conductivity.
In example 1 and comparative example 6, the addition of a small amount of DCC slightly improved the cycle performance of the battery because the components of the battery were inevitably doped with a small amount of moisture and acid during the production of the battery, and these small amounts of acid and water were able to react with the isocyanate-based compound and participate in the formation of a film, but a linear or network polymer film could not be formed, and the degree of encapsulation to the electrode surface was reduced, while the addition of DCC preferentially reacted with water and acid to assist the formation of a film, thereby improving the cycle performance of the battery.
In summary, the additive of the lithium ion battery electrolyte provided by the invention comprises DCC, an amino compound and an isocyanate compound, and the film forming stability of the traditional film decorating additives VC, FEC and PS can be effectively improved through the synergistic effect of the three additive components, so that the lithium ion battery prepared by the lithium ion battery electrolyte has excellent high-voltage high-temperature cycle performance and rate capability.
The above is only a preferred embodiment of the present invention, and it is not intended to limit the scope of the invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall be included in the scope of the present invention.

Claims (6)

1. A lithium ion battery electrolyte, which is characterized by comprising a non-aqueous organic solvent, a lithium salt and an additive, wherein the additive comprises dicyclohexylcarbodiimide, an amino compound and an isocyanate compound, as well as fluoroethylene carbonate, vinylene carbonate and 1,3-propane sultone;
the addition amount of the dicyclohexylcarbodiimide is 0.05-0.15% of the total mass of the lithium ion battery electrolyte; the addition amount of the amino compound is 0.2-1.0% of the total mass of the lithium ion battery electrolyte; the addition amount of the isocyanate compound is 1.0-2.0% of the total mass of the lithium ion battery electrolyte;
the amino compound is at least one of the compounds with the structures shown in the structural formulas of the following compounds B1 to B8:
Figure FDA0002433864360000011
the isocyanate compound is at least one of compounds with the structures shown in the structural formulas of the following compounds A1-A9:
Figure FDA0002433864360000021
2. the lithium ion battery electrolyte of claim 1, wherein the non-aqueous organic solvent is added in an amount of 68-85% of the total mass of the lithium ion battery electrolyte;
the addition amount of the lithium salt is 8-15% of the total mass of the lithium ion battery electrolyte;
the additive of fluoroethylene carbonate, vinylene carbonate and 1,3-propane sultone is 5-12%, 0.1-1.0% and 0.1-1.0% of the total mass of the lithium ion battery electrolyte.
3. The lithium ion battery electrolyte of claim 2, wherein the non-aqueous organic solvent is added in an amount of 68-75% of the total mass of the lithium ion battery electrolyte;
the addition amount of the lithium salt is 10-15% of the total mass of the lithium ion battery electrolyte.
4. The lithium ion battery electrolyte of claim 1 wherein the non-aqueous organic solvent comprises a mixture of two or three of ethylene carbonate, dimethyl carbonate, propylene carbonate, butylene carbonate, γ -butyrolactone, methyl propyl carbonate, ethyl propyl carbonate, propyl acetate, ethyl propionate, propyl propionate, diethyl carbonate, and methyl ethyl carbonate; and/or the presence of a gas in the gas,
the lithium salt comprises lithium bis (oxalato) borate, lithium bis (trifluoromethylsulfonyl) imide, lithium tetrafluoroborate, lithium bis (fluorosulfonato) imide, lithium difluorooxalato borate, lithium difluorophosphate, lithium difluorooxalato phosphate and a mixture of lithium tetrafluorooxalato phosphate and lithium hexafluorophosphate.
5. A lithium ion battery, comprising a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and an electrolyte filled in the positive electrode and the negative electrode, wherein the electrolyte is the lithium ion battery electrolyte according to any one of claims 1 to 4.
6. The lithium ion battery of claim 5, wherein the active material of the positive electrode is LiNixCoyMnzM1-x-y-zO2Or LiNixCoyAlzM1-x-y-zO2Wherein M is any one of Co, Ni, Mn, Mg, Cu, Zn, Al, Sn, B, Ga, Cr, Sr, V and Ti, y is more than or equal to 0 and less than or equal to 1, x is more than or equal to 0 and less than 1, z is more than or equal to 0 and less than or equal to 1, and x + y + z is less than or equal to 1; and/or the presence of a gas in the gas,
the active material of the negative electrode is a silicon-carbon composite material.
CN201811071593.5A 2018-09-13 2018-09-13 Lithium ion battery electrolyte and lithium ion battery Active CN109216759B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201811071593.5A CN109216759B (en) 2018-09-13 2018-09-13 Lithium ion battery electrolyte and lithium ion battery

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201811071593.5A CN109216759B (en) 2018-09-13 2018-09-13 Lithium ion battery electrolyte and lithium ion battery

Publications (2)

Publication Number Publication Date
CN109216759A CN109216759A (en) 2019-01-15
CN109216759B true CN109216759B (en) 2020-06-19

Family

ID=64984270

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201811071593.5A Active CN109216759B (en) 2018-09-13 2018-09-13 Lithium ion battery electrolyte and lithium ion battery

Country Status (1)

Country Link
CN (1) CN109216759B (en)

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112510256B (en) * 2019-09-16 2023-08-29 浙江省化工研究院有限公司 Lithium ion battery electrolyte and lithium ion battery containing same
CN109873205B (en) * 2019-02-27 2021-03-26 杉杉新材料（衢州）有限公司 Electrolyte suitable for silicon-carbon cathode and lithium ion battery containing electrolyte
CN110176631A (en) * 2019-06-12 2019-08-27 广州天赐高新材料股份有限公司 A kind of lithium secondary cell electrolyte and lithium secondary battery reducing the internal resistance of cell
CN111129586A (en) * 2019-12-20 2020-05-08 东莞市杉杉电池材料有限公司 High-voltage lithium cobalt oxide lithium ion battery non-aqueous electrolyte and lithium ion battery
CN111106386A (en) * 2019-12-27 2020-05-05 惠州市豪鹏科技有限公司 Electrolyte and lithium ion battery
CN111668547B (en) * 2020-06-30 2021-09-24 远景动力技术(江苏)有限公司 Nonaqueous electrolyte solution and electricity storage device using same
CN112448035B (en) * 2020-11-25 2022-08-12 东莞市天丰电源材料有限公司 High-voltage lithium ion battery electrolyte and preparation method thereof
CN114583241B (en) * 2020-11-30 2024-08-13 三明市海斯福化工有限责任公司 Lithium ion battery
CN114583243B (en) * 2020-11-30 2024-07-02 三明市海斯福化工有限责任公司 Lithium ion battery
CN114583240B (en) * 2020-11-30 2024-08-09 深圳新宙邦科技股份有限公司 Lithium ion battery
CN114583242B (en) * 2020-11-30 2024-08-09 深圳新宙邦科技股份有限公司 Lithium ion battery
CN113270632A (en) * 2021-05-13 2021-08-17 东莞市杉杉电池材料有限公司 High-nickel ternary lithium ion battery electrolyte and lithium ion battery containing same
CN113809397B (en) * 2021-08-05 2023-03-14 蜂巢能源科技有限公司 Electrolyte, lithium ion battery and application of electrolyte additive
WO2024178681A1 (en) * 2023-03-01 2024-09-06 宁德时代新能源科技股份有限公司 Electrolyte solution, battery cell comprising same, battery, and electric device

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001313073A (en) * 2000-02-25 2001-11-09 Mitsubishi Paper Mills Ltd Non-aqueous system electrolyte, non-aqueous system gel- like composite and electrochemical element using same
JP5319899B2 (en) * 2007-08-23 2013-10-16 株式会社東芝 Non-aqueous electrolyte battery
US8795903B2 (en) * 2008-08-19 2014-08-05 California Institute Of Technology Lithium-ion electrolytes containing flame retardant additives for increased safety characteristics
US10381685B2 (en) * 2014-10-02 2019-08-13 Lg Chem, Ltd. Liquid electrolyte additive for lithium secondary battery, non-aqueous liquid electrolyte and lithium secondary battery comprising the same

Also Published As

Publication number Publication date
CN109216759A (en) 2019-01-15

Similar Documents

Publication Publication Date Title
CN109216759B (en) Lithium ion battery electrolyte and lithium ion battery
CN109873206B (en) Lithium ion battery electrolyte and lithium ion battery
CN109950620B (en) Non-aqueous electrolyte for lithium ion battery and lithium ion battery
CN111883839B (en) High-voltage electrolyte and lithium ion battery based on same
CN107863556B (en) Lithium ion battery with high nickel material as anode and silicon carbon material as cathode and electrolyte thereof
CN109728340B (en) Lithium ion battery
CN110048164B (en) Soft package lithium ion silicon carbon battery electrolyte and lithium ion battery
CN111525190B (en) Electrolyte and lithium ion battery
CN111403807B (en) Lithium ion battery non-aqueous electrolyte and lithium ion battery
CN112928332B (en) High-voltage lithium ion battery non-aqueous electrolyte and lithium ion battery
CN114520371B (en) Nonaqueous electrolyte and lithium ion battery comprising same
CN111129590A (en) High-voltage lithium ion battery non-aqueous electrolyte and high-voltage lithium ion battery
CN113437363A (en) Non-aqueous electrolyte and secondary battery thereof
CN110336076B (en) Lithium ion battery electrolyte and lithium ion battery
CN112635835A (en) Non-aqueous electrolyte and lithium ion battery with high and low temperature consideration
CN109768327B (en) Non-aqueous electrolyte of lithium ion battery and lithium ion battery using same
CN112615056B (en) Additive composition for preparing electrolyte, electrolyte containing additive composition and lithium ion secondary battery
WO2022213668A1 (en) Electrolyte additive and non-aqueous electrolyte and lithium ion battery containing additive
CN111384439A (en) Non-aqueous electrolyte and lithium ion battery
CN111900474A (en) Electrolyte for natural graphite cathode lithium ion battery
CN116093430B (en) High-voltage nonaqueous electrolyte and lithium ion secondary battery
CN110611123A (en) Lithium ion battery electrolyte and lithium ion battery
CN109802176B (en) Electrolyte and lithium ion battery containing electrolyte
CN114883648B (en) Non-aqueous electrolyte of lithium ion battery and lithium ion battery
CN117219859A (en) Lithium ion battery electrolyte, preparation method and application

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant
TR01 Transfer of patent right
TR01 Transfer of patent right

Effective date of registration: 20221108

Address after: 524051 No. 1, Juxin Road, Guandu Industrial Park, Potou District, Zhanjiang City, Guangdong Province

Patentee after: ZHANJIANG JUXIN NEW ENERGY Co.,Ltd.

Address before: No. 01, Brunei Road, ASEAN Industrial Park, Fenyong Hi tech Zone, Zhanjiang, Guangdong 524200

Patentee before: ZHANJIANG JINCANCAN TECHNOLOGY CO.,LTD.