CN112582675B - Electrolyte and lithium ion battery - Google Patents

Electrolyte and lithium ion battery Download PDF

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CN112582675B
CN112582675B CN202011371633.5A CN202011371633A CN112582675B CN 112582675 B CN112582675 B CN 112582675B CN 202011371633 A CN202011371633 A CN 202011371633A CN 112582675 B CN112582675 B CN 112582675B
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carbonate
electrolyte
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alkyl
silicon
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CN112582675A (en
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汪仕华
余乐
王仁和
李轶
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Envision Power Technology Jiangsu Co Ltd
Envision Ruitai Power Technology Shanghai Co Ltd
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Envision Power Technology Jiangsu Co Ltd
Envision Ruitai Power Technology Shanghai Co Ltd
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    • 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
    • H01M2220/00—Batteries for particular applications
    • H01M2220/20—Batteries in motive systems, e.g. vehicle, ship, plane
    • 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

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Abstract

The invention discloses an electrolyte and a lithium ion battery. The electrolyte includes a non-aqueous solvent, a lithium salt, a compound represented by formula I, and an additive. The electrolyte has higher electrochemical stability at high temperature, and further improves the efficiency and the service life of a lithium ion battery containing the electrolyte.

Description

Electrolyte and lithium ion battery
Technical Field
The embodiment of the invention relates to an electrolyte and a lithium ion battery.
Background
A common negative electrode material for current commercial lithium ion batteries is graphite. At present, along with the popularization of electric automobiles, people put forward higher requirements on the energy density of lithium ion batteries in order to meet long endurance. However, the specific mass capacity of the graphite electrode in the prior art reaches 360-365mAh/g, which is very close to the theoretical specific mass capacity 372mAh/g, and the space for further replacing the specific mass capacity is very limited. Due to the fact that the silicon negative electrode has higher theoretical specific capacity (3580mAh/g), the silicon negative electrode becomes the main development direction of the negative electrode of the next generation of high-energy density battery.
The inventor finds that at least the following problems exist in the prior art: the silicon negative electrode expands and contracts to a large extent in the charging and discharging processes, so that an SEI film on the surface of the negative electrode is continuously broken and generated, and a large amount of electrolyte and active ingredient lithium are consumed, so that the cycle life of lithium ions using the silicon negative electrode is far shorter than that of a lithium ion battery using a graphite negative electrode, and the commercial popularization of the silicon negative electrode is limited. In the prior art, the problem of volume expansion of the electrode is solved by a method of surface modification of a silicon negative electrode material, and researches related to development of an electrolyte system matched with a silicon negative electrode are rarely reported.
Disclosure of Invention
The embodiment of the invention aims to provide an electrolyte, so that a lithium ion battery containing the electrolyte provided by the embodiment of the invention has better chemical stability and better high-temperature performance.
In order to realize the purpose, the invention adopts the following technical scheme:
the invention provides an electrolyte, which comprises a compound represented by a formula I, an additive, a lithium salt and a non-aqueous solvent;
Figure RE-GDA0002953867010000011
wherein R is 1 、R 2 、R 3 、R 4 、R 5 And R 6 Independently hydrogen or an electron donating group that does not contain an active hydrogen.
In some preferred embodiments, R 1 、R 2 、R 3 、R 4 、R 5 And R 6 Independently of one another is hydrogen, C 1-4 Alkyl and halogen substituted C 1-4 Alkyl radical, C 1-4 And not simultaneously hydrogen; or, R 1 、R 2 Together with the silicon to which it is attached form C 5-7 Of a cyclic silyl group, R 3 、R 4 Independently of one another is hydrogen, C 1-4 Alkyl and halogen substituted C 1-4 Alkyl radical, R 5 、R 6 Together with the silicon to which they are attached form C 5-7 The cyclic silane group of (1); alternatively, the compound represented by formula I is
Figure RE-GDA0002953867010000021
R 1 、R 2 、R 5 And R 6 Independently of one another is hydrogen, C 1-4 Alkyl and halogen substituted C 1-4 Alkyl, wherein n is 5, 6 or 7.
The compound represented by the formula I can be used in the conventional amount of additives in the electrolyte in the field, and preferably, the mass percentage of the compound in the electrolyte is 0.1-2%, for example, 0.5%.
The lithium salt may be a conventional lithium salt in the art, and is preferably LiPF 6 、LiBF 4 、LiClO 4 、LiAsO 4 One or more of LiTFSI and LiFSI.
The amount of the lithium salt can be conventional in the art, and is preferably 5 to 25 mass percent in the electrolyte. For example, 12.5%.
The additive is preferably one or more of Vinylene Carbonate (VC), fluoroethylene carbonate (F-EC), Vinyl Ethylene Carbonate (VEC), vinyl sulfate (DTD), vinylene sulfate, 1, 3-Propane Sultone (PS), propenyl sultone and 1, 4-butane sultone, and is more preferably a mixture of vinylene carbonate and 1, 3-propane sultone. In the mixture of vinylene carbonate and 1, 3-propane sultone, the mass ratio of vinylene carbonate to 1, 3-propane sultone is preferably 1: 0.5-1: 2, for example, 1: 1.
The additive can be used in the conventional amount of the additive in the electrolyte in the field, and the mass percentage of the additive in the electrolyte is preferably 1-4%, for example, 2%.
The non-aqueous solvent may be a non-aqueous solvent conventional in the art, preferably an ester solvent, more preferably a carbonate solvent. Among them, the carbonate-based solvent is preferably one or more of methylpropyl carbonate (MPC), ethylene carbonate, fluoroethylene carbonate, ethylmethyl carbonate (EMC), Ethylene Carbonate (EC), Propylene Carbonate (PC), and Butylene Carbonate (BC), and more preferably a mixture of ethylene carbonate, fluoroethylene carbonate, and methylethyl carbonate. In the mixture of ethylene carbonate, fluoroethylene carbonate and ethyl methyl carbonate, the mass ratio of ethylene carbonate, fluoroethylene carbonate and ethyl methyl carbonate is preferably 1 (0.5-2.0) to (5-15), for example, 15:15: 70.
in some preferred embodiments, R 1 、R 2 、R 3 、R 4 、R 5 And R 6 Independently is C 1-4 Alkyl and halogen substituted C 1-4 An alkyl group. Said C 1-4 Alkyl is preferably methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl or tert-butyl. The halogen is preferably fluorine, chlorine, bromine or iodine. Said halogen substituted C 1-4 Alkyl is preferably halogen-substituted C 1-2 Alkyl, more preferably halogen substitutedThe methyl group, for example,
Figure RE-GDA0002953867010000022
in some preferred embodiments, R 1 、R 2 、R 3 、R 4 、R 5 And R 6 Independently of each other hydrogen and C 1-4 At least one of the alkyl groups is hydrogen and not simultaneously hydrogen. Said C 1-4 The alkyl group is preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group or a tert-butyl group.
In some preferred embodiments, R 1 、R 2 、R 3 、R 4 、R 5 And R 6 Independently is phenyl or C 1-4 An alkoxy group.
In some preferred embodiments, R 1 、R 2 Together with the silicon to which they are attached form C 5-7 Of a cyclic silyl group, R 3 、R 4 Independently is C 1-4 Alkyl radical, R 5 、R 6 Together with the silicon to which they are attached form C 5-7 A cyclic silane group of (2). Said C 1-4 The alkyl group is preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group or a tert-butyl group. When R is 1 、R 2 Together with the silicon to which it is attached form C 5-7 When there is a cyclic silyl group, said C 5-7 The cyclic silane group(s) of (b) is preferably a cyclopentasilane group, a cyclohexasilane group or a cycloheptasilane group. When R is 5 、 R 6 Together with the silicon to which they are attached form C 5-7 When there is a cyclic silyl group, said C 5-7 The cyclic silyl group of (a) is preferably a cyclopentylsilyl group, a cyclohexylsilyl group or a cycloheptylsilyl group.
In some preferred embodiments, the compound of formula I is
Figure RE-GDA0002953867010000031
R 1 、R 2 、R 5 And R 6 Independently is C 1-4 An alkyl group. Said C 1-4 The alkyl group is preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group or a tert-butyl group.
Preferably, the compound represented by the formula I is any one of the following compounds:
Figure RE-GDA0002953867010000032
the invention also provides a lithium ion battery which is composed of the positive electrode, the negative electrode, the diaphragm and the electrolyte.
The lithium battery of the present invention comprises a positive electrode, a negative electrode, a separator and the above electrolyte. Components other than the electrolytic solution, such as a positive electrode and a negative electrode, can be used without particular limitation.
As the positive electrode active material of the lithium battery described in the present invention, a lithium-containing composite oxide may be used. Specific examples of the lithium-containing composite oxide include LiMnO2, LiFeO2, LiMn2O4, Li2FeSiO4 LiNi1/3Co1/3Mn1/3O2, LiNi5CO2Mn3O2, LizNi (1-x-y) CoxMyO2(x, y, and z are values satisfying 0.01. ltoreq. x.ltoreq.0.20, 0. ltoreq. y.ltoreq.0.20, and 0.97. ltoreq. z.ltoreq.1.20, M represents at least one element selected from the group consisting of Mn, V, Mg, Mo, Nb, and Al), LiFePO4, and LizCO (1-x) MxO2(x and z are values satisfying 0. ltoreq. x.ltoreq.0.1.1 and 0.97. ltoreq. z.ltoreq.1.20, and M represents at least one element selected from the group consisting of Mn, Ni, V, Mg, Mo, Nb, and Al.
From the viewpoint that the additive for an electrolytic solution of the present embodiment can effectively cover the surface, the positive electrode active material may be LizNi (1-x-y) CoxMyO2(x, y and z are values satisfying 0.01. ltoreq. x.ltoreq.0.15, 0. ltoreq. y.ltoreq.0.15 and 0.97. ltoreq. z.ltoreq.1.20, M represents at least one element selected from Mn, Ni, V, Mg, Mo, Nb and Al) or LizCO (1-x) MxO2(x and z are values satisfying 0. ltoreq. x.ltoreq.0.1 and 0.97. ltoreq. z.ltoreq.1.20, and M represents at least one element selected from Mn, V, Mg, Mo, Nb and Al). In particular, when a positive electrode active material having a high Ni ratio, such as LizNi (1-x-y) CoxMyO2 (where x, y, and z are values satisfying 0.01. ltoreq. x.ltoreq.0.15, 0. ltoreq. y.ltoreq.0.15, and 0.97. ltoreq. z.ltoreq.1.20, and M represents at least one element selected from the group consisting of Mn, Ni, V, Mg, Mo, Nb, and Al), is used, gas generation tends to be easily generated, but even in this case, gas generation can be effectively suppressed by the combination of the above-described electrolyte components.
It should be understood that the electrolyte described in the present invention is not limited to be used in a lithium ion battery with a silicon negative electrode, but can also be used in an electrolyte for a lithium ion battery with other negative electrodes (such as a graphite negative electrode), which has the beneficial effects of capturing acidic byproducts generated at high temperature and providing the electrolyte with higher electrochemical stability at high temperature. The negative active material of the lithium battery described in the present invention is a material capable of inserting and extracting lithium. Including, but not limited to, carbon materials such as crystalline carbon (natural graphite, artificial graphite, and the like), amorphous carbon, carbon-coated graphite, and resin-coated graphite, and oxide materials such as indium oxide, silicon oxide, tin oxide, lithium titanate, zinc oxide, and lithium oxide. The negative electrode active material may also be lithium metal or a metal material that can form an alloy with lithium. Specific examples of metals that can be alloyed with lithium include Cu, Sn, Si, Co, Mn, Fe, Sb, and Ag. Binary or ternary alloys containing these metals and lithium may also be used as the negative electrode active material. These negative electrode active materials may be used alone, or two or more of them may be used in combination. From the viewpoint of high energy density, a carbon material such as graphite and an Si-based active material such as Si, an Si alloy, and an Si oxide may be combined as the negative electrode active material. From the viewpoint of both cycle characteristics and high energy density, graphite and an Si-based active material may be combined as the negative electrode active material. In the combination, the ratio of the mass of the Si-based active material to the total mass of the carbon material and the Si-based active material may be 0.5% to 95%, 1% to 50%, or 2% to 40%.
The separator for a lithium ion battery is not particularly limited, and a single-layer or laminated microporous film, woven fabric, nonwoven fabric, or the like of polyolefin such as polypropylene or polyethylene can be used.
On the basis of the common knowledge in the field, the above preferred conditions can be combined randomly to obtain the preferred embodiments of the invention.
The reagents and starting materials used in the present invention are commercially available.
The positive progress effects of the invention are as follows:
the electrolyte has higher electrochemical stability at high temperature, and further improves the efficiency and the service life of a lithium ion battery containing the electrolyte.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the following detailed description of the embodiments of the present invention is provided. However, it will be appreciated by those of ordinary skill in the art that numerous technical details are set forth in order to provide a better understanding of the present application in various embodiments of the present invention. However, the technical solution claimed in the present application can be implemented without these technical details and various changes and modifications based on the following embodiments.
The present invention will be described in further detail with reference to the following examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Experimental procedures in the following examples, where no detailed conditions are indicated, are generally carried out according to conventional conditions, or according to conditions recommended by the manufacturer. Unless otherwise indicated, percentages and parts are by weight. The test materials and reagents used in the following examples are commercially available without specific reference.
[ PREPARATION EXAMPLES ]
Preparation of electrolyte
Example 1
Under the inert gas atmosphere with the water content of less than 5ppm, mixing ethylene carbonate, fluoroethylene carbonate and methyl ethyl carbonate according to the mass ratio of 15:15:70 to prepare 1000mL of a non-aqueous mixed solvent, adding lithium hexafluorophosphate into the prepared non-aqueous solvent, and uniformly mixing to completely dissolve the lithium salt. Then Vinylene Carbonate (VC), 1, 3-Propane Sultone (PS) and the additive shown in the formula I are respectively added and evenly mixed to obtain the electrolyte. In the obtained electrolyte, the mass percent of lithium hexafluorophosphate is 12.25%, the mass percent of Vinylene Carbonate (VC) is 1%, the mass percent of 1, 3-Propane Sultone (PS) is 1%, the mass percent of the additive shown in the formula I is 0.5%, and the balance is a non-aqueous solvent.
Figure RE-GDA0002953867010000051
The compound shown in the formula I has a Chinese name: hexamethyldisiloxane.
Example 2
Under the inert gas atmosphere with the water content of less than 5ppm, mixing ethylene carbonate, fluoroethylene carbonate and methyl ethyl carbonate according to the mass ratio of 15:15:70 to prepare 1000mL of a non-aqueous mixed solvent, adding lithium hexafluorophosphate into the prepared non-aqueous solvent, and uniformly mixing to completely dissolve the lithium salt. Then Vinylene Carbonate (VC), 1, 3-Propane Sultone (PS) and the additive shown in the formula II are respectively added and evenly mixed to obtain the electrolyte. In the obtained electrolyte, the mass percent of lithium hexafluorophosphate is 12.25%, the mass percent of Vinylene Carbonate (VC) is 1%, the mass percent of 1, 3-Propane Sultone (PS) is 1%, the mass percent of the additive shown in the formula II is 0.5%, and the balance is a non-aqueous solvent.
Figure RE-GDA0002953867010000052
The compound shown in the formula II has a Chinese name: pentamethylbutyl disiloxane.
Example 3
Under the inert gas atmosphere with the water content of less than 5ppm, mixing ethylene carbonate, fluoroethylene carbonate and methyl ethyl carbonate according to the mass ratio of 15:15:70 to prepare 1000mL of a non-aqueous mixed solvent, adding lithium hexafluorophosphate into the prepared non-aqueous solvent, and uniformly mixing to completely dissolve the lithium salt. Then Vinylene Carbonate (VC), 1, 3-Propane Sultone (PS) and the additive shown in the formula III are respectively added and evenly mixed to obtain the electrolyte. In the obtained electrolyte, the mass percent of lithium hexafluorophosphate is 12.25%, the mass percent of Vinylene Carbonate (VC) is 1%, the mass percent of 1, 3-Propane Sultone (PS) is 1%, the mass percent of the additive shown in the formula III is 0.5%, and the balance is a non-aqueous solvent.
Figure RE-GDA0002953867010000061
The compound shown in the formula III is named as: hexapropyl disiloxaneAn alkane.
Example 4
Under the inert gas atmosphere with the water content of less than 5ppm, mixing ethylene carbonate, fluoroethylene carbonate and methyl ethyl carbonate according to the mass ratio of 15:15:70 to prepare 1000mL of a non-aqueous mixed solvent, adding lithium hexafluorophosphate into the prepared non-aqueous solvent, and uniformly mixing to completely dissolve the lithium salt. Then Vinylene Carbonate (VC), 1, 3-Propane Sultone (PS) and the additive shown in the formula IV are respectively added and evenly mixed to obtain the electrolyte. In the obtained electrolyte, the mass percent of lithium hexafluorophosphate is 12.25%, the mass percent of Vinylene Carbonate (VC) is 1%, the mass percent of 1, 3-Propane Sultone (PS) is 1%, the mass percent of the additive shown in the formula IV is 0.5%, and the balance is a non-aqueous solvent.
Figure RE-GDA0002953867010000062
The compound shown in the formula IV has a Chinese name: tetramethylcyclohexadisiloxane.
Example 5
Under the inert gas atmosphere with the water content of less than 5ppm, mixing ethylene carbonate, fluoroethylene carbonate and methyl ethyl carbonate according to the mass ratio of 15:15:70 to prepare 1000mL of a non-aqueous mixed solvent, adding lithium hexafluorophosphate into the prepared non-aqueous solvent, and uniformly mixing to completely dissolve the lithium salt. Then Vinylene Carbonate (VC), 1, 3-Propane Sultone (PS) and the additive shown in the formula V are respectively added and evenly mixed to obtain the electrolyte. In the obtained electrolyte, the mass percent of lithium hexafluorophosphate is 12.25%, the mass percent of Vinylene Carbonate (VC) is 1%, the mass percent of 1, 3-Propane Sultone (PS) is 1%, the mass percent of the additive shown in the formula V is 0.5%, and the balance is a non-aqueous solvent.
Figure RE-GDA0002953867010000063
The compound shown in the formula V is named as: dimethylcyclobicyclobutyldisiloxane.
Example 6
Under the inert gas atmosphere with the water content of less than 5ppm, mixing ethylene carbonate, fluoroethylene carbonate and methyl ethyl carbonate according to the mass ratio of 15:15:70 to prepare 1000mL of a non-aqueous mixed solvent, adding lithium hexafluorophosphate into the prepared non-aqueous solvent, and uniformly mixing to completely dissolve the lithium salt. Then Vinylene Carbonate (VC), 1, 3-Propane Sultone (PS) and the additive shown in the formula VI are respectively added and evenly mixed to obtain the electrolyte. In the obtained electrolyte, the mass percent of lithium hexafluorophosphate is 12.25%, the mass percent of Vinylene Carbonate (VC) is 1%, the mass percent of 1, 3-Propane Sultone (PS) is 1%, the mass percent of the additive shown in the formula VI is 0.5%, and the balance is a non-aqueous solvent.
Figure RE-GDA0002953867010000071
The compound of formula VI is referred to herein by the generic name: tetramethyl difluoromethyl disiloxane.
Example 7
Under the inert gas atmosphere with the water content of less than 5ppm, mixing ethylene carbonate, fluoroethylene carbonate and methyl ethyl carbonate according to the mass ratio of 15:15:70 to prepare 1000mL of non-aqueous mixed solvent, adding lithium hexafluorophosphate into the prepared non-aqueous solvent, and uniformly mixing to completely dissolve lithium salt to prepare the lithium ion battery. Then Vinylene Carbonate (VC), 1, 3-Propane Sultone (PS) and the additive shown in the formula VII are respectively added and evenly mixed to obtain the electrolyte. In the obtained electrolyte, the mass percent of lithium hexafluorophosphate is 12.25%, the mass percent of Vinylene Carbonate (VC) is 1%, the mass percent of 1, 3-Propane Sultone (PS) is 1%, the mass percent of the additive shown in the formula VII is 0.5%, and the balance is a non-aqueous solvent.
Figure RE-GDA0002953867010000072
The compound shown in the formula VII is named as: pentamethyldisiloxane.
Example 8
Under the inert gas atmosphere with the water content of less than 5ppm, mixing ethylene carbonate, fluoroethylene carbonate and methyl ethyl carbonate according to the mass ratio of 15:15:70 to prepare 1000mL of non-aqueous mixed solvent, adding lithium hexafluorophosphate into the prepared non-aqueous solvent, and uniformly mixing to completely dissolve lithium salt to prepare the lithium ion battery. Then Vinylene Carbonate (VC), 1, 3-Propane Sultone (PS) and the additive shown in the formula VIII are respectively added and evenly mixed to obtain the electrolyte. In the obtained electrolyte, the mass percent of lithium hexafluorophosphate is 12.25%, the mass percent of Vinylene Carbonate (VC) is 1%, the mass percent of 1, 3-Propane Sultone (PS) is 1%, the mass percent of the additive shown in formula VIII is 0.5%, and the balance is a non-aqueous solvent.
Figure RE-GDA0002953867010000073
The compound of formula VIII is referred to by the generic name: hexamethoxydisiloxane.
Example 9
Under the inert gas atmosphere with the water content of less than 5ppm, mixing ethylene carbonate, fluoroethylene carbonate and methyl ethyl carbonate according to the mass ratio of 15:15:70 to prepare 1000mL of non-aqueous mixed solvent, adding lithium hexafluorophosphate into the prepared non-aqueous solvent, and uniformly mixing to completely dissolve lithium salt to prepare the lithium ion battery. Then Vinylene Carbonate (VC), 1, 3-Propane Sultone (PS) and the additive shown in the formula X are respectively added and evenly mixed to obtain the electrolyte. In the obtained electrolyte, the mass percent of lithium hexafluorophosphate is 12.25%, the mass percent of Vinylene Carbonate (VC) is 1%, the mass percent of 1, 3-Propane Sultone (PS) is 1%, the mass percent of the additive shown in the formula X is 0.5%, and the balance is a non-aqueous solvent.
Figure RE-GDA0002953867010000081
The compound shown in the formula X has the following name: hexaphenyldisiloxane.
Comparative example 1
Under the inert gas atmosphere with the water content of less than 5ppm, mixing ethylene carbonate, fluoroethylene carbonate and methyl ethyl carbonate according to the mass ratio of 15:15:70 to prepare 1000mL of non-aqueous mixed solvent, adding lithium hexafluorophosphate into the prepared non-aqueous solvent, and uniformly mixing to completely dissolve lithium salt to prepare the lithium ion battery. Then Vinylene Carbonate (VC) and 1, 3-Propane Sultone (PS) are respectively added and evenly mixed to obtain the electrolyte. In the obtained electrolyte, the mass percent of lithium hexafluorophosphate is 12.25%, the mass percent of Vinylene Carbonate (VC) is 1%, the mass percent of 1, 3-Propane Sultone (PS) is 1%, and the balance is a non-aqueous solvent.
Lithium ion battery preparation
Preparation of Positive plate
A positive electrode active material lithium nickel cobalt manganese oxide lini0.8co0.1mn0.1o2, conductive carbon black Super-P and a binder polyvinylidene fluoride (PVDF) were mixed in a mass ratio of 93:4:3, and then dispersed in N-methyl-2-pyrrolidone (NMP) to obtain a positive electrode slurry. And uniformly coating the slurry on two sides of the aluminum foil, drying, rolling and vacuum drying, and welding an aluminum outgoing line by using an ultrasonic welding machine to obtain the positive plate, wherein the thickness of the positive plate is 120-150 mu m.
Preparation of negative plate
The negative electrode active material artificial graphite, the silicon oxide (carbon coating), the conductive carbon black Super-P, the binder Styrene Butadiene Rubber (SBR) and the carboxymethyl cellulose (CMC) are mixed according to the mass ratio of 80:14:1:2.5:2.5, and then dispersed in deionized water to obtain negative electrode slurry. Coating the slurry on two sides of a copper foil, drying, rolling and vacuum drying, and welding a nickel outgoing line by using an ultrasonic welding machine to obtain a negative plate, wherein the thickness of the negative plate is 120-150 mu m.
Preparation of battery cell
And placing three layers of isolating films with the thickness of 20 mu m between the positive plate and the negative plate, then winding the sandwich structure consisting of the positive plate, the negative plate and the diaphragm, flattening the wound body, then placing the wound body into an aluminum foil packaging bag, and baking for 48h at 85 ℃ in vacuum to obtain the battery cell to be injected with liquid.
Liquid injection formation of battery core
And injecting the prepared electrolyte into a battery cell in a glove box with the dew point controlled below-40 ℃, carrying out vacuum packaging, and standing for 24 h. Then the first charge is normalized according to the following steps: charging to 3.05V at 0.02C, 3.75V at 0.05C, 4.05V at 0.2C, and vacuum sealing. Then, the battery was further charged to 4.2V by a constant current of 0.33C, and after being left at room temperature for 24 hours, the battery was discharged to 3.0V by a constant current of 0.2C.
In other examples and comparative examples, lithium ion batteries were fabricated in the same manner as in example 1, except that the additives used were different, as specified in table 1 below.
TABLE 1
Figure RE-GDA0002953867010000091
Figure RE-GDA0002953867010000101
In the table, the percentage refers to the mass percentage of each substance in the electrolyte.
[ test examples ]
Battery performance testing
Normal temperature cycle life test
The full-charged battery after capacity grading was placed in an incubator at 25 ℃ and discharged to 3.0V at 1C, and the initial discharge capacity was designated as DC (1). Charging to 4.2V at constant current and constant voltage of 1C, stopping current at 0.05C, standing for 5min, discharging to 3.0V at 1C, and recording discharge capacity DC (2). This is cycled through until dc (n) < 80%. And recording the discharge times N, wherein N is the high-temperature cycle life. The results of measurements of the batteries prepared in the respective examples and comparative examples are shown in table 2 below.
High temperature cycle life test
The full-charged battery after capacity grading was placed in a 45 ℃ incubator and discharged to 3.0V at 1C, and the initial discharge capacity was recorded as DC (1). Charging to 4.2V at constant current and constant voltage of 1C, stopping current at 0.05C, standing for 5min, discharging to 3.0V at 1C, and recording discharge capacity DC (2). This is cycled through until dc (n) < 80%. And recording the discharge times N, wherein N is the high-temperature cycle life. The results of measurements of the batteries prepared in the respective examples and comparative examples are shown in table 2 below. High temperature storage capacity retention and recovery test
High temperature storage capacity retention and recovery test
The full-state battery after capacity separation was discharged to 3.0V at room temperature at 1C, and the initial discharge capacity was recorded as DC (0). The cell was placed in an incubator at 60 ℃ for N days, the cell was taken out and discharged to 3.0V at room temperature, and the discharge capacity DC (N-1) was recorded, and the storage capacity Retention was 100% DC (N-1)/DC (0). Charging to 4.2V at constant current and constant voltage of 1C, stopping current at 0.05C, standing for 5min, and discharging to 3.0V at 1C. The average discharge capacity DC (N-2) was recorded after 3 cycles, and the storage capacity Recovery was 100% DC (N-2)/DC (0). The results are shown in Table 2.
TABLE 2
Figure RE-GDA0002953867010000102
Figure RE-GDA0002953867010000111
It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples for carrying out the invention, and that various changes in form and details may be made therein without departing from the spirit and scope of the invention in practice.

Claims (10)

1. An electrolyte for a lithium ion battery is characterized by comprising a compound represented by formula I, an additive, a lithium salt and a non-aqueous solvent;
Figure FDA0003813646920000011
wherein R is 1 、R 2 Together with the silicon to which they are attached form a 5-to 7-membered cyclic silane group, R 3 、R 4 Independently of one another is hydrogen, C 1-4 Alkyl or halogen substituted C 1-4 Alkyl radical, R 5 、R 6 And silicon to which it is attached form a 5 to 7 membered cyclic silane group; alternatively, the compound represented by formula I is
Figure FDA0003813646920000012
R 1 、R 2 、R 5 And R 6 Independently of one another is hydrogen, C 1-4 Alkyl or halogen substituted C 1-4 Alkyl, wherein n is 5, 6 or 7.
2. The electrolyte according to claim 1, wherein the compound represented by the formula I is contained in the electrolyte in an amount of 0.1 to 2% by mass;
and/or, the lithium salt is LiPF 6 、LiBF 4 、LiClO 4 、LiAsO 4 One or more of LiTFSI and LiFSI;
and/or the molar concentration of the lithium salt in the electrolyte is 0.5-2.0M;
and/or the additive is selected from one or more of Vinylene Carbonate (VC), fluoroethylene carbonate (F-EC), ethylene carbonate (VEC), vinyl sulfate (DTD), vinylene sulfate, 1, 3-Propane Sultone (PS), propenyl sultone and 1, 4-butane sultone;
and/or the mass percentage of the additive in the electrolyte is 1-4%;
and/or the non-aqueous solvent is an ester solvent.
3. The electrolyte of claim 2, wherein the additive is a mixture of vinylene carbonate and 1, 3-propane sultone;
and/or the non-aqueous solvent is a carbonate solvent.
4. The electrolyte according to claim 3, wherein in the mixture of vinylene carbonate and 1, 3-propane sultone, the mass ratio of vinylene carbonate to 1, 3-propane sultone is 1: 0.5-1: 2;
and/or the carbonate solvent is selected from one or more of Methyl Propyl Carbonate (MPC), ethylene carbonate, fluoroethylene carbonate, Ethyl Methyl Carbonate (EMC), Ethylene Carbonate (EC), Propylene Carbonate (PC) and Butylene Carbonate (BC).
5. The electrolyte of claim 4, wherein the carbonate-based solvent is a mixture of ethylene carbonate, fluoroethylene carbonate and ethyl methyl carbonate.
6. The electrolyte of claim 5, wherein in the mixture of ethylene carbonate, fluoroethylene carbonate and methyl ethyl carbonate, the mass ratio of ethylene carbonate, fluoroethylene carbonate and methyl ethyl carbonate is 1 (0.5-2.0) to (5-15).
7. The electrolyte of claim 1, wherein R is 1 、R 2 Together with the silicon to which they are attached form a 5-to 7-membered cyclic silane group, R 3 、R 4 Independently is C 1-4 Alkyl radical, R 5 、R 6 And the silicon to which it is attached form a 5 to 7 membered cyclic silane group;
or, the compound represented by formula I is
Figure FDA0003813646920000021
R 1 、R 2 、R 5 And R 6 Independently is C 1-4 An alkyl group.
8. The electrolyte of claim 7,
when R is 1 、R 2 Together with the silicon to which they are attached form a 5-to 7-membered cyclic silane group, R 3 、R 4 Independently is C 1-4 Alkyl radical, R 5 、R 6 Together with the silicon to which they are attached form a 5-to 7-membered cyclic silane group, C 1-4 Alkyl is methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl or tert-butyl;
and/or when R 1 、R 2 When taken together with the silicon to which they are attached form a 5-to 7-membered cyclic silane group, the 5-to 7-membered cyclic siliconAlkyl is cyclopentasilyl, cyclohexasilyl or cycloheptasilyl;
and/or when R 5 、R 6 And the silicon to which it is attached form a 5-to 7-membered cyclic silyl group, said 5-to 7-membered cyclic silyl group is a cyclopentasilyl group, a cyclohexasilyl group, or a cycloheptasilyl group;
and/or, when the compound represented by formula I is
Figure FDA0003813646920000022
R 1 、R 2 、R 5 And R 6 Independently is C 1-4 When alkyl, said C 1-4 Alkyl is methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl or tert-butyl.
9. The electrolyte of claim 8, wherein the compound of formula I is
Figure FDA0003813646920000023
Figure FDA0003813646920000024
10. A lithium ion battery comprising a positive electrode, a negative electrode, a separator and the electrolyte according to any one of claims 1 to 9.
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106519834A (en) * 2016-11-25 2017-03-22 广东国立科技股份有限公司 Modified polymer coating and preparation method thereof
CN108807813A (en) * 2018-05-25 2018-11-13 欣旺达电子股份有限公司 Lithium ion battery, diaphragm and preparation method thereof
CN109265617A (en) * 2018-09-12 2019-01-25 江苏中路交通科学技术有限公司 A kind of preparation method of silicane-modified polyurethane modified aqueous acrylic acid material and its application in the sealing of mist containing sand
CN111063849A (en) * 2019-11-08 2020-04-24 扬州工业职业技术学院 Dual-drive self-assembly-based lithium ion battery isolating membrane and preparation method thereof

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106519834A (en) * 2016-11-25 2017-03-22 广东国立科技股份有限公司 Modified polymer coating and preparation method thereof
CN108807813A (en) * 2018-05-25 2018-11-13 欣旺达电子股份有限公司 Lithium ion battery, diaphragm and preparation method thereof
CN109265617A (en) * 2018-09-12 2019-01-25 江苏中路交通科学技术有限公司 A kind of preparation method of silicane-modified polyurethane modified aqueous acrylic acid material and its application in the sealing of mist containing sand
CN111063849A (en) * 2019-11-08 2020-04-24 扬州工业职业技术学院 Dual-drive self-assembly-based lithium ion battery isolating membrane and preparation method thereof

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