CN116646604A - Oxygen-containing silane additive, electrolyte and lithium ion battery - Google Patents

Oxygen-containing silane additive, electrolyte and lithium ion battery Download PDF

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CN116646604A
CN116646604A CN202310919486.8A CN202310919486A CN116646604A CN 116646604 A CN116646604 A CN 116646604A CN 202310919486 A CN202310919486 A CN 202310919486A CN 116646604 A CN116646604 A CN 116646604A
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lithium
electrolyte
additive
carbonate
equal
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杨小龙
梁大宇
刘欣
黄波
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Hefei Gotion High Tech Power Energy Co Ltd
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Hefei Guoxuan High Tech Power Energy 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
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic Table
    • C07F7/02—Silicon compounds
    • C07F7/08—Compounds having one or more C—Si linkages
    • C07F7/0834—Compounds having one or more O-Si linkage
    • C07F7/0838—Compounds with one or more Si-O-Si sequences
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic Table
    • C07F7/02—Silicon compounds
    • C07F7/08—Compounds having one or more C—Si linkages
    • C07F7/0896—Compounds with a Si-H linkage
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic Table
    • C07F7/02—Silicon compounds
    • C07F7/08—Compounds having one or more C—Si linkages
    • C07F7/12—Organo silicon halides
    • 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
    • H01M2200/00—Safety devices for primary or secondary 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

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  • Inorganic Chemistry (AREA)
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Abstract

The application provides an oxygen-containing silane additive, electrolyte and a lithium ion battery. The oxy-silane additive comprises a structure shown in a formula I:a formula I; wherein R is 1 Represents H, substituted or unsubstituted C 1 ~C 20 Alkyl, substituted or unsubstituted C 1 ~C 20 Any one of alkenyl, substituted or unsubstituted phenyl, each R 2 Each R is 3 Each R is 4 Each independently represents H, takeSubstituted or unsubstituted C 1 ~C 6 Any one of the alkyl groups of (a). The additive of the application can be combined with solvated lithium ions to activate intercalation or deintercalation of lithium ions in the anode and the cathode. The additive in the application is trisiloxane molecules, and three siloxanes are connected around each Si, so that the effect of siloxane groups in the reaction of the electrolyte is enhanced, the metal electrode and the electrolyte components are further protected, the reaction interface of the battery is stabilized, and the safety of the battery is improved.

Description

Oxygen-containing silane additive, electrolyte and lithium ion battery
Technical Field
The application relates to the technical field of lithium ion batteries, in particular to an oxygen-containing silane additive, electrolyte and a lithium ion battery.
Background
Lithium ion batteries have played an important role in many fields such as mobile phones, computers, new energy automobiles and the like by virtue of the advantages of high specific energy, long cycle life, high specific power and the like. The lithium iron phosphate battery is widely applied to the power market based on the advantages of high safety, low cost and the like, but has relatively low energy density and limited endurance mileage, so that further application of the lithium iron phosphate battery is limited. In contrast, the high-nickel ternary battery has high energy density and good multiplying power, and has been widely applied to new energy markets, especially in fields with high multiplying power performance requirements. In order to further improve the performance of the battery, it is necessary to have a low impedance of the battery, because an excessively high impedance of the battery not only affects the capacity of the battery, but also increases the heat generation of the battery, and further causes a safety problem when the heat generation is serious, so that it is necessary to reduce the impedance of the battery.
Disclosure of Invention
The application mainly aims to provide an oxysilane additive, electrolyte and a lithium ion battery, so as to solve the problem of overhigh impedance of the battery in the prior art.
In order to achieve the above object, according to one aspect of the present application, there is provided an alkoxysilane additive comprising a structure represented by formula I:
a formula I;
wherein R is 1 Represents H, substituted or unsubstituted C 1 ~C 20 Alkyl, substituted or unsubstituted C 1 ~C 20 Any one of alkenyl, substituted or unsubstituted phenyl, each R 2 Each R is 3 Each R is 4 Each independently represents H, substituted or unsubstituted C 1 ~C 6 Any one of the alkyl groups of (a).
Further, R 1 Representation H, C 1 ~C 10 Straight or branched alkyl, C 1 ~C 10 Alkenyl, phenyl; preferably each R 2 Each R is 3 Each R is 4 Each independently represent H, C 1 ~C 6 Any of the straight or branched alkyl groups of (a).
Further, R 1 Represents any one of H, methyl and vinyl, and R is preferably each 2 Each R is 3 Each R is 4 Each independently represents H and/or methyl; more preferably, each R 2 Identical, each R 3 Identical, each R 4 The same applies.
Further, the alkoxysilane additive is selected from、、/>Any one of the following.
In order to achieve the above object, according to another aspect of the present application, there is provided an electrolyte comprising a lithium salt, a solvent, an additive, the electrolyte comprising one or more of the above-mentioned alkoxysilane additives.
Further, the additive further comprises other additives besides the oxygen-containing silane additive, wherein the other additives are selected from one or more of fluoroethylene carbonate, ethylene carbonate, methyl disulfonate, 1, 3-propane sultone, 1, 4-butane sultone, 1, 3-propylene sultone, vinyl sulfate, propylene sulfate, phenyl sulfone and polyether sulfone; preferably, the conventional additive is selected from the group consisting of vinylene carbonate and 1, 3-propane sultone, and preferably the weight of the conventional additive is 1-5% of the total weight of the electrolyte.
Further, the lithium salt includes one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bistrifluoromethylsulfonylimide, lithium difluorophosphate, lithium difluorooxalato borate, lithium difluorooxalato phosphate, lithium difluorosulfonylimide salt, lithium methylsulfonate, lithium bisoxalato borate, lithium perchlorate, preferably the lithium salt is any one of lithium hexafluorophosphate, a combination of lithium hexafluorophosphate and lithium difluorosulfonylimide salt, and a combination of lithium hexafluorophosphate and lithium difluorooxalato borate; preferred solvents include one or more of ethylene carbonate, fluoroethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methylethyl carbonate, methylpropyl carbonate, propyl acetate, ethyl acetate, propyl propionate.
Further, the weight of the lithium salt is 10-20% of the total weight of the electrolyte; preferably, the weight of the oxygen-containing silane additive is 1-10% of the total weight of the electrolyte.
According to still another aspect of the present application, there is provided a lithium ion battery including a positive electrode, a negative electrode, an electrolyte, and a separator disposed between the positive electrode and the negative electrode, the electrolyte being the electrolyte described above.
Further, the positive electrode comprises a ternary material, preferably the ternary positive electrode material is a nickel cobalt lithium manganate ternary material, more preferably the ternary material has the general formula Li [ Ni ] x Co y Mn z ]O 2 Wherein, the values of x, y and z satisfy the following conditions: x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, z is more than or equal to 0 and less than or equal to 1, and x is more than or equal to 0 and less than or equal to 1; preferably the negative electrode comprises a negative electrode material, preferably the negative electrode material comprises one or more of natural graphite, artificial graphite, silicon.
By applying the technical scheme of the application, the additive can be combined with solvated lithium ions to activate intercalation or deintercalation of lithium ions in the anode and the cathode. Specifically, the lone pair electrons of oxygen atoms in the siloxane functional groups can chemically react with hydroxide ions, silicon can combine with fluoride ions, HF is consumed and generation of HF is inhibited in the combination and subsequent reaction processes of the additive and lithium ions, collection is prevented from being corroded, meanwhile, the conductivity of the lithium ions is increased, and DCR of the battery is reduced; finally, a film forming component such as LiF Guan Jiemian is generated on the surfaces of the positive electrode and the negative electrode, so that electrolyte can be effectively isolated, and the rate capability of the battery is improved. Compared with the traditional siloxane molecules, the additive is trisiloxane molecules, and three siloxanes are connected around each Si, so that the effect of siloxane groups in the electrolyte reaction is enhanced, the metal electrode and electrolyte components are further protected, the reaction interface of the battery is stabilized, and the safety of the battery is improved.
Detailed Description
It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other. The present application will be described in detail with reference to examples.
As analyzed in the background art, the battery impedance is too high, which not only affects the battery capacity, but also increases the heat generation of the battery, and the safety problem is further generated when the heat generation is serious. In order to solve the problems, the application provides an oxygen-containing silane additive, an electrolyte and a lithium ion battery.
In one exemplary embodiment of the present application, an alkoxysilane additive is provided that includes a structure of formula I:
a formula I; wherein R is 1 Represents H, substituted or unsubstituted C 1 ~C 20 Alkyl, substituted or unsubstituted C 1 ~C 20 Any one of an olefinic group, a substituted or unsubstituted phenyl group, each R 2 Each R is 3 Each R is 4 Each independently represents H, substituted or unsubstituted C 1 ~C 6 Any one of the alkyl groups of (a).
The additive of the application can be combined with solvated lithium ions to activate intercalation or deintercalation of lithium ions in the anode and the cathode. Specifically, the lone pair electrons of oxygen atoms in the siloxane functional groups can chemically react with hydroxide ions, silicon can combine with fluoride ions, HF is consumed and generation of HF is inhibited in the combination and subsequent reaction processes of the additive and lithium ions, collection is prevented from being corroded, meanwhile, the conductivity of the lithium ions is increased, and DCR of the battery is reduced; finally, a film forming component such as LiF Guan Jiemian is generated on the surfaces of the positive electrode and the negative electrode, so that electrolyte can be effectively isolated, and the rate capability of the battery is improved. Compared with the traditional siloxane molecules, the additive is trisiloxane molecules, and three siloxanes are connected around each Si, so that the effect of siloxane groups in the electrolyte reaction is enhanced, the metal electrode and electrolyte components are further protected, the reaction interface of the battery is stabilized, and the safety of the battery is improved.
To further reduce the DCR of the battery and increase lithium ion conductivity, in some embodiments, R 1 Representation H, C 1 ~C 10 Straight or branched alkyl, C 1 ~C 10 One of an alkylene group and a phenyl group; preferably each R 2 Each R is 3 Each R is 4 Each independently represent H, C 1 ~C 6 Any of the straight or branched alkyl groups of (a).
In some embodiments, R 1 Represents any one of H, methyl and vinyl, each R 2 Each R is 3 Each R is 4 Each independently represents H and/or methyl; more preferably, each R 2 Identical, each R 3 Identical, each R 4 The same applies.
In some embodiments, the alkoxysilane additive may be selected from、、/>Any one of the following.
In another exemplary embodiment of the present application, an electrolyte is provided, the electrolyte comprising a lithium salt, a solvent, and an additive, the electrolyte comprising one or more of the above-described oxysilane additives.
The electrolyte containing the additive can form a layer of compact and stable film on the surfaces of the positive electrode and the negative electrode, can effectively isolate the electrolyte, inhibit the generation of HF, prevent the positive electrode from being corroded, increase the lithium ion conductivity and reduce the DCR of the battery.
In some embodiments, the additive further includes other additives other than the alkoxysilane additive, and the present application is not particularly limited in the kind and amount of other additives, and additives commonly used in the art may be applied to the present application. Preferably, the other additive is selected from one or more of fluoroethylene carbonate, vinylene carbonate, methyl disulfonate, 1, 3-propane sultone, 1, 4-butane sultone, 1, 3-propylene sultone, vinyl sulfate, propylene sulfate, phenyl sulfone and polyether sulfone; preferably, the weight of the conventional additive is 1-5% of the total weight of the electrolyte.
The present application is not particularly limited to the lithium salt and the solvent, and the lithium salt and the solvent commonly used in the art may be used in the present application, and the lithium salt includes one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bistrifluoromethylsulfonylimide, lithium difluorophosphate, lithium difluorooxalato borate, lithium difluorooxalato phosphate, lithium difluorosulfonylimide salt, lithium methylsulfonate, lithium bisoxalato borate, lithium perchlorate; preferred solvents include one or more of ethylene carbonate, fluoroethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methylethyl carbonate, methylpropyl carbonate, propyl acetate, ethyl acetate, propyl propionate.
In some embodiments, the weight of the lithium salt is 10-20% of the total weight of the electrolyte, for example, the weight of the lithium salt may be 10%, 13.5%, 16%, 18%, 20% of the total weight of the electrolyte; preferably, the weight of the alkoxysilane additive is 1 to 10% of the total weight of the electrolyte, for example, the weight of the alkoxysilane additive is 1%, 3%, 6%, 9%, 10% of the total weight of the electrolyte. Too much of the oxygen-containing silane additive increases the film thickness and thus the battery impedance; too little of the alkoxysilane additive may result in poor film formation, and the additive may be consumed before a dense film is formed, and thus the additive may not be fully used.
In another exemplary embodiment of the present application, there is provided a lithium ion battery including a positive electrode, a negative electrode, an electrolyte, and a separator disposed between the positive electrode and the negative electrode, the electrolyte being the electrolyte described above.
The battery comprising the electrolyte has good ploidy and good safety.
The oxygen-containing silane additive of the applicationSuitable for use in NCM ternary systems, in some embodiments, the positive electrode comprises a ternary material, preferably the ternary positive electrode material is a nickel cobalt lithium manganate ternary material, more preferably the ternary material has the general formula Li [ Ni ] x Co y Mn z ]O 2 Wherein, the values of x, y and z satisfy the following conditions: x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, z is more than or equal to 0 and less than or equal to 1, and x is more than or equal to 0 and less than or equal to 1. The battery with the additive can form a dense and stable film on the surfaces of the NCM positive electrode and the graphite negative electrode, can effectively isolate electrolyte, inhibit HF from generating, prevent the positive electrode from being corroded, increase lithium ion conductivity and reduce DCR of the battery.
The kind of the anode material is not particularly limited in the present application, and anode materials commonly used in the art can be applied to the present application. In some embodiments, the negative electrode comprises a negative electrode material, preferably the negative electrode material comprises one or more of natural graphite, artificial graphite, silicon.
The application is described in further detail below in connection with specific examples which are not to be construed as limiting the scope of the application as claimed.
Example 1
Preparation of electrolyte: mixing Ethylene Carbonate (EC), diethyl carbonate (DEC) and methyl ethyl carbonate (EMC) according to the mass ratio of EC: DEC: EMC=3:2:5, and adding 2.0% of ethylene carbonate (VC), 1% of 1, 3-Propane Sultone (PS) and 13.5% of lithium hexafluorophosphate (LiPF) 6 ) After the lithium salt is completely dissolved, 1.0% of an oxygen-containing silane additive is added, wherein the structure of the oxygen-containing silane additive is shown as a formula I:
formula I.
Example 2
The difference from example 1 is that the lithium salt in example 1 was replaced with 10.0% lithium hexafluorophosphate (LiPF) 6 ) +3.5% lithium bis (fluorosulfonyl) imide (LiFSI).
Example 3
Ethylene Carbonate (EC), diethyl carbonate (DEC) and methyl ethyl carbonate (EMC) are mixed according to the mass ratio of EC DEC emc=3:2:5, and after mixing, adding 2.0% Vinylene Carbonate (VC), 0.5% 1, 3-propenesulfonic acid lactone (PES) and lithium salt 15.0% lithium hexafluorophosphate (LiPF) 6 ) After the lithium salt is completely dissolved, 1.0% of an oxygen-containing silane additive is added, and the structure of the oxygen-containing silane additive is shown as a formula II.
Formula II.
Example 4
The difference from example 3 is that the lithium salt is 13.0% lithium hexafluorophosphate (LiPF 6 ) +2.0% lithium bis (fluorosulfonyl) imide (LiFSI).
Example 5
Mixing Ethylene Carbonate (EC), diethyl carbonate (DEC) and methyl ethyl carbonate (EMC) according to the mass ratio of EC: DEC: EMC=3:2:5, and adding 1.0% of ethylene carbonate (VC), 1.0% of ethylene sulfate (DTD) and 18.0% of lithium hexafluorophosphate (LiPF) 6 ) After the lithium salt is completely dissolved, 1.0% of an oxygen-containing silane additive is added, wherein the structure of the oxygen-containing silane additive is shown as a formula III:
formula III.
Example 6
The difference from example 5 is that the lithium salt is 16.0% lithium hexafluorophosphate (LiPF 6 ) +2.0% lithium difluorooxalato borate (LiODFB).
Example 7
The difference from example 1 is that 10% of an alkoxysilane additive is added.
Example 8
The difference from example 1 is that 12% of an alkoxysilane additive is added.
Comparative example 1
The difference from example 1 is that the electrolyte does not contain an alkoxysilane additive.
Comparative example 2
The difference from example 2 is that the electrolyte does not contain an oxy-silane additive.
Comparative example 3
The difference from example 3 is that the electrolyte does not contain an alkoxysilane additive.
Comparative example 4
The difference from example 4 is that the electrolyte does not contain an alkoxysilane additive.
Comparative example 5
The difference from example 5 is that the electrolyte does not contain an oxy-silane additive.
Comparative example 6
The difference from example 6 is that the electrolyte does not contain an alkoxysilane additive.
Comparative example 7
The difference from example 1 is that the alkoxysilane additive in example 1 is replaced by a structure of formula IV:
formula IV.
Assembled battery
(1) Preparation of a positive plate: ternary material Li [ Ni0 ] 0.75 C0 0.1 Mn 0.15 ]O 2 Uniformly mixing the conductive agent, the adhesive and the carbon nano tube to prepare lithium ion battery anode slurry with certain viscosity, and coating the slurry on an aluminum foil; then slitting, slicing, and baking for 4 hours at the temperature of 85 ℃ in vacuum to prepare the lithium ion battery positive plate meeting the requirements.
(2) Preparing a negative plate: mixing artificial graphite, a conductive agent, a thickening agent and an adhesive uniformly to prepare slurry, coating the slurry on two sides of a copper foil, drying and rolling the slurry to obtain a negative plate, and then drying the negative plate at the temperature of 85 ℃ for 4 hours in vacuum to prepare the negative plate of the lithium ion battery meeting the requirements.
(3) Preparation of a lithium ion battery: the positive plate, the negative plate and the diaphragm prepared according to the process are manufactured into a lithium ion battery through a lamination process, the lithium ion battery is baked for 48 hours at the temperature of 85 ℃ in vacuum, and the electrolyte prepared in each example and the comparative example is injected to complete the battery manufacturing.
The specific electrolyte formulations in the above examples and comparative examples are shown in table 1 below:
TABLE 1
Initial DCR test
After capacity division, the experimental batteries in examples and comparative examples were charged to a full state, respectively. In the normal temperature DCR test, the discharge is performed for 90min at a discharge speed of 0.33C; and then standing for 30min to enable the battery to reach a 50% SOC state. Then record the end voltage V at this time 0 Recording the sampling voltage V after discharge is finished after the discharge is carried out for 10 seconds by using the 6A current 1 Calculating initial direct current discharge impedance DCR= (V) of experimental battery 0 -V 1 )/I。
Cycle performance detection
The experimental batteries in the examples and the comparative examples were respectively subjected to charge-discharge cycle performance test at a charge-discharge rate of 1C under a test condition of 25C, a charge-discharge voltage interval was set to 2.8 to 4.25v, and the cycle was continued for 300 weeks at normal temperature, recording capacity retention rate.
The battery performance results of each example and comparative example are shown in table 2 below:
TABLE 2
In addition to the normal temperature DCR, we also tested the low temperature DCR of the battery in 50% SOC state. Similar to the calculation procedure for normal temperature DCR, low temperature DCR values for the cells were obtained, see in particular table 2.
As can be seen from tables 1 and 2, the DCR test results of the examples and the comparative examples show that the low-resistance electrolyte additive of the present application can effectively reduce the DCR at normal and low temperatures.
The results of normal temperature cycle test of the electrolyte and the experimental battery in the examples and the comparative examples show that compared with the conventional additive, the additive and the electrolyte provided by the application have the advantages that the normal temperature cycle capacity retention rate is increased by about 5%, the DCR is increased by about 10%, and the low temperature DCR is reduced by about 5%.
In summary, it can be seen that the oxy-silane additive of the present application can act to reduce DCR and enhance circulation at normal and low temperatures as compared to other conventional additives.
As can be seen from comparative examples 1 and 2 and comparative examples 5 and 6, liFSI was combined with LiPF for lithium salts 6 Improved circulation, deteriorated DCR, liODFB and LiPF 6 The collocation effect is better, the circulation is improved, and the normal temperature DCR is reduced. This is mainly because LiODFB can coordinate with the high-nickel ternary positive electrode, and suppresses precipitation of transition metals. For conventional additives, the addition of a 1% VC+1% DTD combination is a better option.
In example 8, since the alkoxysilane itself was used as an additive instead of a solvent, an excessively high content of 12% was disadvantageous in terms of reduction of impedance.
From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects: the additive of the application can be combined with solvated lithium ions to activate intercalation or deintercalation of lithium ions in the anode and the cathode. Specifically, the lone pair electrons of oxygen atoms in the siloxane functional groups can chemically react with hydroxide ions, silicon can combine with fluoride ions, HF is consumed and generation of HF is inhibited in the combination and subsequent reaction processes of the additive and lithium ions, collection is prevented from being corroded, meanwhile, the conductivity of the lithium ions is increased, and DCR of the battery is reduced; finally, a film forming component such as LiF Guan Jiemian is generated on the surfaces of the positive electrode and the negative electrode, so that electrolyte can be effectively isolated, and the rate capability of the battery is improved. Compared with the traditional siloxane molecules, the additive in the application is trisiloxane molecules, and three siloxanes are connected around each Si, so that the effect of siloxane groups in the electrolyte reaction is enhanced, the metal electrode and the electrolyte components are further protected, the reaction interface of the battery is stabilized, and the safety of the battery is improved.
The above description is only of the preferred embodiments of the present application and is not intended to limit the present application, but various modifications and variations can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims (10)

1. An oxysilane additive, wherein said oxysilane additive comprises a structure of formula I:
a formula I;
wherein R is 1 Represents H, substituted or unsubstituted C 1 ~C 20 Alkyl, substituted or unsubstituted C 1 ~C 20 Any one of alkenyl, substituted or unsubstituted phenyl, each R 2 Each R is 3 Each R is 4 Each independently represents H, substituted or unsubstituted C 1 ~C 6 Any one of the alkyl groups of (a).
2. The oxysilane additive of claim 1, wherein said R 1 Representation H, C 1 ~C 10 Straight or branched alkyl, C 1 ~C 10 Alkenyl, phenyl;
each R is 2 Each R 3 Each R 4 Each independently represent H, C 1 ~C 6 Any of the straight or branched alkyl groups of (a).
3. The oxysilane additive of claim 1, wherein said R 1 Represents any one of H, methyl and vinyl, each R 2 Each R 3 Each R 4 Each independently represents H and/or methyl; and/or
Each R is 2 Identical, each of said R 3 Identical, each of said R 4 The same applies.
4. An alkoxysilane additive according to any of claims 1 to 3 wherein the alkoxysilane additive is selected from the group consisting of、/>、/>Any one of the following.
5. An electrolyte comprising a lithium salt, a solvent, and an additive, wherein the electrolyte comprises one or more of the oxysilane additives of any one of claims 1 to 4.
6. The electrolyte of claim 5 wherein the additives further comprise other additives than the oxysilane additive and/or conventional additives, the other additives selected from one or more of fluoroethylene carbonate, vinylene carbonate, methylene methyldisulfonate, 1, 3-propane sultone, 1, 4-butane sultone, 1, 3-propene sultone, vinyl sulfate, propylene sulfate, phenyl sulfone, polyether sulfone; and/or
The conventional additives are selected from the group consisting of vinylene carbonate and 1, 3-propane sultone, and/or
The weight of the conventional additive is 1-5% of the total weight of the electrolyte.
7. The electrolyte of claim 5, wherein the lithium salt comprises one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bistrifluoromethylsulfonimide, lithium difluorophosphate, lithium difluorooxalato borate, lithium difluorooxalato phosphate, lithium bisthiomide salt, lithium methylsulfonate, lithium bisthiooxalato borate, lithium perchlorate, and/or
The lithium salt is any one of lithium hexafluorophosphate, a combination of lithium hexafluorophosphate and lithium difluorosulfimide salt and a combination of lithium hexafluorophosphate and lithium difluorooxalato borate; and/or
The solvent comprises one or more of ethylene carbonate, fluoroethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, propyl acetate, ethyl acetate and propyl propionate.
8. The electrolyte according to claim 5, wherein the weight of the lithium salt is 10-20% of the total weight of the electrolyte;
the weight of the oxygen-containing silane additive is 1-10% of the total weight of the electrolyte.
9. A lithium ion battery comprising a positive electrode, a negative electrode, an electrolyte, and a separator disposed between the positive electrode and the negative electrode, wherein the electrolyte is the electrolyte of any one of claims 5 to 8.
10. The lithium-ion battery of claim 9, wherein the positive electrode comprises a ternary material, and/or
The ternary positive electrode material is a nickel cobalt lithium manganate ternary material, and the general formula of the ternary material is Li [ Ni ] x Co y Mn z ]O 2 Wherein, the values of x, y and z satisfy the following conditions: x is more than or equal to 0 and less than or equal to 1, y is more than or equal to 0 and less than or equal to 1, z is more than or equal to 0 and less than or equal to 1, and x is more than or equal to 0 and less than or equal to 1;
the negative electrode comprises a negative electrode material, and the negative electrode material comprises one or more of natural graphite, artificial graphite and silicon.
CN202310919486.8A 2023-07-24 2023-07-24 Oxygen-containing silane additive, electrolyte and lithium ion battery Pending CN116646604A (en)

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