CN115799636A - Lithium secondary battery electrolyte, lithium secondary battery and electric equipment - Google Patents
Lithium secondary battery electrolyte, lithium secondary battery and electric equipment Download PDFInfo
- Publication number
- CN115799636A CN115799636A CN202211526957.0A CN202211526957A CN115799636A CN 115799636 A CN115799636 A CN 115799636A CN 202211526957 A CN202211526957 A CN 202211526957A CN 115799636 A CN115799636 A CN 115799636A
- Authority
- CN
- China
- Prior art keywords
- secondary battery
- lithium secondary
- electrolyte
- battery
- 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.)
- Granted
Links
Classifications
-
- 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
- Secondary Cells (AREA)
Abstract
The application provides a lithium secondary battery electrolyte, a lithium secondary battery and electric equipment, and belongs to the field of lithium secondary battery manufacturing. The additive in the lithium secondary battery electrolyte comprises tetracyanoalkoxy aliphatic straight-chain alkane and tri (trimethyl silane) borate and/or tri (trimethyl silane) phosphite ester with structural formulas shown as formula I and/or formula II, and the electrolyte can solve the problem that the rate performance, the cycle performance, the storage performance and the like of the battery are poor at high temperature and high pressure to a certain extent.
Description
Technical Field
The application relates to the field of manufacturing of lithium secondary batteries, in particular to a lithium secondary battery electrolyte, a lithium secondary battery and electric equipment.
Background
In the prior art, the performance of the electrolyte as an important component of the battery determines the performance of the battery, and although the electrolyte with the existing components has better comprehensive electrical performance at low temperature, the battery using the existing electrolyte components has the problem of poor rate performance, cycle performance, storage performance and the like at high temperature and high pressure.
Disclosure of Invention
An object of the present application is to provide a lithium secondary battery electrolyte, a lithium secondary battery, and an electric device, which can solve, to a certain extent, the problem that the electrolyte causes poor performance such as rate capability, cycle performance, and storage performance of the battery at high temperature and high pressure.
The embodiment of the application is realized as follows:
in a first aspect, embodiments of the present application provide an electrolyte for a lithium secondary battery, where an additive in the electrolyte for a lithium secondary battery includes: tetracyanoalkoxy aliphatic straight-chain alkane with a structural formula shown as a formula I and/or a formula II; and tris (trimethylsilane) borate and/or tris (trimethylsilane) phosphite;
formula I is shown below:
formula II is as follows:
in the above technical solution, on the one hand: the oxidation potential of the tetracyanoalkoxy aliphatic straight-chain alkane with the structure is high, the tetracyanoalkoxy aliphatic straight-chain alkane is not easily oxidized at high temperature and high pressure, and a cyano group of the compound has strong complexing capability and can be coordinated with lithium ions so as to reduce desolvation energy of a battery and improve the rate capability of the battery; meanwhile, the compound has ether bonds with larger elasticity, and can effectively deal with stress change caused by electrode expansion in the charge and discharge processes of a negative electrode, so that the compound is also beneficial to improving the rate capability of the battery; in addition, oxygen atoms in the alkoxy groups are easy to combine with lithium ions, so that the enrichment degree of the lithium ions on the surface of the positive electrode can be improved, and the impedance of the battery is effectively reduced. On the other hand, the tri (trimethylsilyl) borate and the tri (trimethylsilyl) phosphite have lower oxidation potential and are easy to lose silicon-containing groups at the interface of the positive electrode to polymerize to form a CEI film, so that the damage to the positive electrode structure caused by the intercalation and deintercalation of lithium ions can be effectively reduced, the reaction between the positive electrode and other materials can be reduced, and the cycle performance of the battery under high temperature and high pressure is improved; meanwhile, the silicon-containing groups can also effectively remove hydrofluoric acid (generated by electrolyte decomposition) in the electrolyte, thereby playing a role in protecting the electrode and being beneficial to improving the cycle performance of the battery; in addition, boron atoms and phosphorus atoms in the tri (trimethyl silane) borate and the tri (trimethyl silane) phosphite ester can also adsorb active oxygen, so that excessive oxidative decomposition of the electrolyte can be effectively avoided, and the storage performance of the battery is improved. Through the combined action of the two components, the stability of the battery under high-temperature and high-pressure conditions can be obviously improved, so that the rate capability, the cycle performance and the storage performance of the battery are obviously improved.
In some alternative embodiments, the additive is present in the electrolyte solution for a lithium secondary battery in an amount of 0.6 to 7% by mass.
In the technical scheme, the mass percent of the additive is limited in a specific range, so that the additive with a proper dosage can be contained in the electrolyte, and a battery using the electrolyte has better rate performance, cycle performance and storage performance at high temperature.
In some optional embodiments, the lithium secondary battery electrolyte has a weight percentage of tetracyanoalkoxy aliphatic linear alkane of 0.5 to 4% and a weight percentage of tris (trimethylsilyl) borate and/or tris (trimethylsilyl) phosphite of 0.1 to 3%.
In the technical scheme, the mass percentage of the tetracyanoalkoxy aliphatic straight-chain alkane in the electrolyte is limited in a specific range, so that the electrolyte has a proper amount of the tetracyanoalkoxy aliphatic straight-chain alkane, the phenomenon that the electrolyte has a proper impedance due to overhigh amount (the electrolyte impedance is too large due to overhigh amount) can be avoided, the phenomenon that the electrolyte has a proper impedance can be effectively avoided, and meanwhile, the phenomenon that the electrolyte has overlow amount (the rate capability of the battery cannot be effectively improved due to overlow amount) can be effectively avoided, so that the rate capability of the battery is effectively improved; the mass percent of the borate in the electrolyte is limited in a specific range, the borate with proper dosage can be made to exist in the electrolyte, so that the phenomenon that the dosage of the borate is too high (the dosage is too high to cause too large impedance of the electrolyte) can be avoided, the electrolyte has impedance with proper size, meanwhile, the phenomenon that the dosage of the borate is too low (the dosage is too low to effectively improve the cycle performance and the storage performance of the battery) can be effectively avoided, and the cycle performance and the storage performance of the battery are effectively improved.
In some alternative embodiments, the organic solvent in the electrolyte for a lithium secondary battery includes at least one of a cyclic carbonate, a chain carbonate, and a carboxylic acid ester.
The additive provided by the embodiment of the application is suitable for various organic solvent systems, and can provide more implementable schemes, so that the additive provided by the embodiment of the application is convenient to popularize and apply.
In some alternative embodiments, the lithium secondary battery electrolyte satisfies at least one of the following conditions a to C:
a, the cyclic carbonate comprises at least one of ethylene carbonate, fluoroethylene carbonate and propylene carbonate;
b, the chain carbonate comprises at least one of dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate;
and C, the carboxylic ester comprises at least one of propyl acetate, ethyl acetate and propyl propionate.
The additive provided by the embodiment of the application is suitable for various cyclic carbonate systems, chain carbonate systems and carboxylic ester systems, and can provide more implementable schemes, so that the additive provided by the embodiment of the application is convenient to popularize and apply.
In some alternative embodiments, the lithium salt in the lithium secondary battery electrolyte comprises LiPF 6 、LiBF 4 、LiB(C 2 O 4 ) 2 、LiBF 2 C 2 O 4 、LiN(SO 2 F) 2 And LiN (SO) 2 CF 3 ) 2 At least one of (1).
The additive provided by the embodiment of the application is suitable for various lithium salt systems, and more implementable schemes can be provided, so that the additive provided by the embodiment of the application is convenient to popularize and apply.
In some alternative embodiments, the lithium salt is present in the electrolyte of the lithium secondary battery in an amount of 0.5 to 20% by mass.
In the technical scheme, the mass percent of the lithium salt in the electrolyte of the lithium secondary battery is limited in a specific range, so that the electrolyte can contain the lithium salt with a proper dosage, and the battery can be ensured to have better comprehensive electrical properties.
In a second aspect, embodiments of the present application provide a lithium secondary battery, including a case, an electrode assembly, and the lithium secondary battery electrolyte provided in embodiments of the first aspect. The electrode assembly is accommodated in the case; the lithium secondary battery electrolyte is contained in the case.
In the above technical solution, the lithium secondary battery includes the lithium secondary battery electrolyte provided in the embodiment of the first aspect, so that the lithium secondary battery has good storage and cycle performance at high temperature and high pressure.
In some alternative embodiments, the positive active material in the electrode assembly comprises LiNi x Co y Mn z O 2 Wherein x + y + z =1.
In the above technical solution, the positive electrode active material is defined as the above system, because the positive electrode active material of the system has the excellent properties of multiple metal materials, and has more excellent electrical properties compared with a single system of positive electrode active material.
In a third aspect, embodiments of the present application provide an electric device, where the electric device includes the lithium secondary battery provided in the second aspect.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application 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.
It should be noted that "and/or" in the present application, such as "feature 1 and/or feature 2" refers to "feature 1" alone, "feature 2" alone, and "feature 1" plus "feature 2" alone.
In addition, in the description of the present application, the meaning of "a plurality" of "one or more" means two or more unless otherwise specified; the range of "numerical value a to numerical value b" includes both values "a" and "b", and "unit of measure" in "numerical value a to numerical value b + unit of measure" represents both "unit of measure" of "numerical value a" and "numerical value b".
The following specifically describes a lithium secondary battery electrolyte, a lithium secondary battery, and an electric device according to the embodiments of the present application.
In a first aspect, embodiments of the present application provide an electrolyte for a lithium secondary battery, where an additive in the electrolyte for a lithium secondary battery includes: tetracyanoalkyloxy aliphatic straight-chain alkane with a structural formula shown in a formula I and/or a formula II; and tris (trimethylsilane) borate and/or tris (trimethylsilane) phosphite;
formula I is shown below:
formula II is as follows:
the electrolyte provided in the examples of the present application may be prepared in a conventional composition except for additives. As an example, the electrolyte solution includes, for example, but not limited to, an organic solvent and a lithium salt in addition to the additive.
In the present application, on the one hand: the oxidation potential of the tetracyanoalkoxy aliphatic straight-chain alkane with the structure is high, the tetracyanoalkoxy aliphatic straight-chain alkane is not easily oxidized at high temperature and high pressure, and a cyano group of the compound has strong complexing capability and can be coordinated with lithium ions so as to reduce desolvation energy of a battery and improve the rate capability of the battery; meanwhile, the compound has a relatively high-elasticity ether bond, and can effectively cope with stress change caused by electrode expansion in the charge and discharge processes of a negative electrode, so that the rate performance of the battery is improved; in addition, oxygen atoms in the alkoxy groups are easy to combine with lithium ions, so that the enrichment degree of the lithium ions on the surface of the positive electrode can be improved, and the impedance of the battery is effectively reduced. On the other hand, the tri (trimethylsilyl) borate and the tri (trimethylsilyl) phosphite have lower oxidation potential and are easy to lose silicon-containing groups at the interface of the positive electrode to polymerize to form a CEI film, so that the damage to the positive electrode structure caused by the intercalation and deintercalation of lithium ions can be effectively reduced, the reaction between the positive electrode and other materials can be reduced, and the cycle performance of the battery under high temperature and high pressure is improved; meanwhile, the silicon-containing groups can also effectively remove hydrofluoric acid (generated by electrolyte decomposition) in the electrolyte, thereby playing a role in protecting the electrode and being beneficial to improving the cycle performance of the battery; in addition, boron atoms and phosphorus atoms in the tri (trimethyl silane) borate and the tri (trimethyl silane) phosphite ester can also adsorb active oxygen, so that excessive oxidative decomposition of the electrolyte can be effectively avoided, and the storage performance of the battery is improved. Through the combined action of the two components, the stability of the battery under high-temperature and high-pressure conditions can be obviously improved, so that the rate capability, the cycle performance and the storage performance of the battery are obviously improved.
It is understood that the electrical property of the electrolyte is related to the amount of the additive, and the amount of the additive in the electrolyte may be limited in consideration of the electrical property of the electrolyte.
As an example, the mass percentage of the additive in the electrolyte of the lithium secondary battery is 0.6 to 7%, such as but not limited to any one of 0.6%, 1%, 2%, 3%, 4%, 5%, 6% and 7% or a range value between any two.
In this embodiment, the mass percentage of the additive is limited to a specific range, so that the additive can be used in an appropriate amount in the electrolyte, and thus, a battery using the electrolyte has good rate performance, cycle performance and storage performance at high temperature.
It is understood that, since the different types of additives correspond to different technical effects, the amounts of the different types of additives may be individually defined in consideration of the overall electrical properties of the battery.
As an example, in the electrolyte of the lithium secondary battery, the mass percentage of the tetracyanoalkoxy aliphatic linear alkane is 0.5 to 4%, such as but not limited to any one of 0.5%, 1%, 2%, 3% and 4% or a range between any two; the mass percent of the tri (trimethylsilyl) borate and/or the tri (trimethylsilyl) phosphite is 0.1 to 3%, such as but not limited to any one of 0.1%, 0.5%, 1%, 2%, and 3% or a range between any two.
In the embodiment, the mass percentage of the tetracyanoalkoxy aliphatic linear alkane in the electrolyte is limited in a specific range, so that the electrolyte has a proper amount of the tetracyanoalkoxy aliphatic linear alkane, the phenomenon that the electrolyte has a proper impedance due to overhigh amount (the electrolyte impedance is too large due to overhigh amount) can be avoided, and meanwhile, the phenomenon that the electrolyte has too low amount (the rate capability of the battery cannot be effectively improved due to overlow amount) can be effectively avoided, so that the rate capability of the battery is effectively improved; the mass percent of the borate in the electrolyte is limited in a specific range, the borate with proper dosage can be made to exist in the electrolyte, so that the phenomenon that the dosage of the borate is too high (the dosage is too high to cause too large impedance of the electrolyte) can be avoided, the electrolyte has impedance with proper size, meanwhile, the phenomenon that the dosage of the borate is too low (the dosage is too low to effectively improve the cycle performance and the storage performance of the battery) can be effectively avoided, and the cycle performance and the storage performance of the battery are effectively improved.
It should be noted that the type of the organic solvent in the electrolyte is not limited, and can be adjusted according to actual needs.
As one example, the organic solvent in the electrolyte for a lithium secondary battery includes at least one of cyclic carbonate, chain carbonate, and carboxylic ester.
In this embodiment, the additive provided in the examples of the present application is suitable for the above-mentioned various organic solvent systems, and can provide more practical embodiments, thereby facilitating popularization and application of the additive provided in the examples of the present application.
It should be noted that the type of each organic solvent is not particularly limited, and may be adjusted according to actual needs.
As an example, the lithium secondary battery electrolyte satisfies at least one of the following conditions a to C:
and A, the cyclic carbonate comprises at least one of ethylene carbonate, fluoroethylene carbonate and propylene carbonate.
And B, the chain carbonate comprises at least one of dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate.
And C, the carboxylic ester comprises at least one of propyl acetate, ethyl acetate and propyl propionate.
In this embodiment, the additive provided in the example of the present application is suitable for various cyclic carbonate systems, chain carbonate systems, and carboxylate systems, and can provide more implementable embodiments, thereby facilitating popularization and application of the additive provided in the example of the present application.
It should be noted that the type of the lithium salt in the electrolyte is not limited, and can be adjusted according to actual needs.
As an example, the lithium salt in the electrolyte of a lithium secondary battery includes LiPF 6 、LiBF 4 、LiB(C 2 O 4 ) 2 、LiBF 2 C 2 O 4 、LiN(SO 2 F) 2 And LiN (SO) 2 CF 3 ) 2 At least one of (1).
In this embodiment, the additive provided in the examples of the present application is suitable for the above-mentioned multiple lithium salt systems, and can provide more practical solutions, thereby facilitating popularization and application of the additive provided in the examples of the present application.
It is understood that the electrical property of the electrolyte is related to the amount of the lithium salt, and the amount of the lithium salt in the electrolyte may be limited in consideration of the electrical property of the electrolyte.
As an example, the mass percentage of the lithium salt in the electrolyte of the lithium secondary battery is 0.5 to 20%, such as but not limited to any one of 0.5%, 1%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, and 20% or a range value between any two.
In the embodiment, the mass percentage of the lithium salt in the electrolyte of the lithium secondary battery is limited in a specific range, so that the electrolyte can contain a proper amount of the lithium salt, and the battery can be ensured to have better comprehensive electrical properties.
In a second aspect, embodiments of the present application provide a lithium secondary battery, including a case, an electrode assembly, and the lithium secondary battery electrolyte provided in embodiments of the first aspect. The electrode assembly is accommodated in the case; the lithium secondary battery electrolyte is contained in the case.
In the present application, a lithium secondary battery includes the lithium secondary battery electrolyte provided in the embodiment of the first aspect, so that the lithium secondary battery has better storage and cycle performance at high temperature and high pressure.
It should be noted that the electrode assembly, also called as a battery cell, includes a positive electrode plate, a separator and a negative electrode plate, which are sequentially disposed.
It is to be noted that the kind of the positive electrode active material in the electrode assembly is not limited, and may be adjusted according to actual needs.
As an example, in the electrode assembly, the positive active material includes LiNi x Co y Mn z O 2 Wherein x + y + z =1.
In this embodiment, the positive electrode active material is limited to the above system because the positive electrode active material of the system has excellent properties of a plurality of metal materials, and thus has more excellent electrical properties than a single positive electrode active material.
The structure of the lithium secondary battery, which is not specifically described, may be selected and provided according to the conventional practice in the art.
In a third aspect, embodiments of the present application provide an electric device, which includes a lithium secondary battery as provided in the second aspect.
It should be noted that the type of the electric device is not limited, and examples of the electric device include a mobile phone, a portable device, a notebook computer, a battery car, an electric car, a ship, a spacecraft, an electric toy, an energy storage device, and an electric tool.
The features and properties of the present application are described in further detail below with reference to examples.
Example 1
The embodiment of the application provides a preparation method of a battery electrolyte, which comprises the following steps:
mixing Ethylene Carbonate (EC), diethyl carbonate (DEC) and Ethyl Methyl Carbonate (EMC) according to a mass ratio of 3; then, lithium hexafluorophosphate (LiPF) was added to the mixed organic solvent 6 ) Tris (trimethylsilane) borate (abbreviated TMSB) and compounds of formula I (BTTN); wherein the organic solvent and LiPF are mixed 6 The mass percentage of TMSB and BTTN is 88.5:10:0.5:1.
example 2
The embodiment of the application provides a preparation method of a battery electrolyte, which is different from the embodiment 1 only in that: 1% by mass of BTTN in the electrolyte was replaced by 1% of the compound of the formula II (CTTN).
Example 3
The embodiment of the application provides a preparation method of a battery electrolyte, which is different from the embodiment 1 only in that: TMSB accounting for 0.5% by mass of the electrolyte was replaced with tris (trimethylsilane) phosphite (abbreviated as TMSP) accounting for 0.5%.
Example 4
The embodiment of the application provides a preparation method of a battery electrolyte, which is different from the embodiment 1 only in that: BTTN accounting for 1% of the electrolyte by mass is replaced by 0.5% of BTTN and 0.5% of CTTN.
Example 5
The embodiment of the application provides a preparation method of a battery electrolyte, which is different from the embodiment 1 only in that: the mass ratio of TMSB of 0.5% is replaced by TMSB of 0.25% and TMSP of 0.25%.
Example 6
The embodiment of the application provides a preparation method of a battery electrolyte, which is different from the embodiment 1 only in that: 1% by mass of BTTN in the electrolyte was replaced with 0.8% of BTTN and 0.2% of 1,2,3-tris (2-cyanato) propane.
Example 7
The embodiment of the application provides a preparation method of a battery electrolyte, which is different from the embodiment 1 only in that: 1% by mass of BTTN in the electrolyte was replaced with 0.8% of BTTN and 0.2% of 1,1,2,2,2-penta (2-cyanooxy) ethane.
Example 8
The embodiment of the application provides a preparation method of a battery electrolyte, which is different from the embodiment 1 only in that: the mass percentage of TMSB in the electrolyte solution of 0.5 percent is replaced by 0.25 percent of TMSB and 0.25 percent of tributyl phosphate.
Example 9
The embodiment of the application provides a preparation method of a battery electrolyte, which is different from the embodiment 1 only in that: the mass percentage of TMSB in the electrolyte solution of 0.5 percent is replaced by 0.25 percent of TMSB and 0.25 percent of triethyl borate.
Example 10
The embodiment of the application provides a preparation method of a battery electrolyte, which is different from the embodiment 1 only in that: the mass percent of BTTN was 4% and the mass percent of TMSB was 3%, and the mass percent changes of both were adjusted by the mass percent of the organic solvent.
Example 11
The embodiment of the application provides a preparation method of a battery electrolyte, which is different from the embodiment 1 only in that: the mass percent of BTTN is 0.5%, the mass percent of TMSB is 0.1%, and the mass percent change of the two is adjusted by the mass percent of the organic solvent.
Example 12
The embodiment of the application provides a preparation method of a battery electrolyte, which is different from the embodiment 1 only in that: the mass percentage of BTTN was 5%, and the mass percentage change thereof was adjusted by the mass percentage of the organic solvent.
Example 13
The embodiment of the application provides a preparation method of a battery electrolyte, which is different from the embodiment 1 only in that: the mass percentage of BTTN was 0.1%, and the mass percentage change thereof was adjusted by the mass percentage of the organic solvent.
Example 14
The embodiment of the application provides a preparation method of a battery electrolyte, which is different from the embodiment 1 only in that: the mass percent of the TMSB was 4%, the mass percent change of which was adjusted by the mass percent of the organic solvent.
Example 15
The embodiment of the application provides a preparation method of a battery electrolyte, which is different from the embodiment 1 only in that: the mass percent of the TMSB was 0.05%, and the mass percent change was adjusted by the mass percent of the organic solvent.
Comparative example 1
The comparative example of the present application provides a method for preparing a battery electrolyte, which is different from example 1 only in that: the electrolyte does not contain BTTN and TMSB, and the mass percentage change of the BTTN and the TMSB is adjusted by the mass percentage of the organic solvent.
Comparative example 2
The comparative example of the present application provides a method for preparing a battery electrolyte, which is different from example 1 only in that: the electrolyte does not contain BTTN, and the mass percentage change thereof is adjusted by the mass percentage of the organic solvent.
Comparative example 3
The comparative example of the present application provides a method for preparing a battery electrolyte, which is different from example 1 only in that: the electrolyte does not contain TMSB, and the mass percent change of the electrolyte is adjusted by the mass percent of the organic solvent.
Comparative example 4
The comparative example of the present application provides a method for preparing a battery electrolyte, which is different from example 1 only in that: the electrolyte does not contain TMSB, 1% of BTTN in mass percentage in the electrolyte is replaced by 1% of CTTN, and the mass percentage change is adjusted by the mass percentage of the organic solvent.
Comparative example 5
The comparative example of the present application provides a method for preparing a battery electrolyte, which is different from example 1 only in that: the electrolyte does not contain BTTN, TMSB accounting for 0.5 percent of the mass of the electrolyte is replaced by TMSP accounting for 0.5 percent of the mass of the electrolyte, and the mass percent change of the TMSB is adjusted by the mass percent of the organic solvent.
Comparative example 6
The comparative example of the present application provides a method for preparing a battery electrolyte, which is different from example 1 only in that: TMSB accounting for 0.5 percent of the mass of the electrolyte is replaced by 0.5 percent of tributyl phosphate.
Comparative example 7
The comparative example of the present application provides a method for preparing a battery electrolyte, which is different from example 1 only in that: the TMSB accounting for 0.5 percent of the mass of the electrolyte is replaced by 0.5 percent of triethyl borate.
Comparative example 8
The comparative example of the present application provides a method for preparing a battery electrolyte, which is different from example 1 only in that: 1 percent of BTTN in the electrolyte is replaced by 1 percent of 1,2,3-tri (2-cyanoxy) propane.
Comparative example 9
The comparative example of the present application provides a method for preparing a battery electrolyte, which is different from example 1 only in that: 1 percent of BTTN in the electrolyte is replaced by 1 percent of 1,1,2,2,2-penta (2-cyano-oxy) ethane.
Comparative example 10
The comparative example of the present application provides a method for preparing a battery electrolyte, which is different from example 1 only in that: 1% of BTTN in the electrolyte is replaced by 1% of tetrakis (2-cyanoethyl) methane.
In order to facilitate understanding of the components and the ratios of the electrolytes of the respective batteries, the following table 1 is used for centralized processing.
The amount of the organic solvent used was the balance excluding the amounts described in table 1 below.
TABLE 1 composition of battery electrolytes of examples and comparative examples
Note that EC represents an abbreviation of ethylene carbonate, DEC represents an abbreviation of diethyl carbonate, and EMC represents an abbreviation of ethyl methyl carbonate.
Test example 1
Electrical Performance testing
The test method comprises the following steps:
the electrolytes prepared in examples 1 to 15 and comparative examples 1 to 10 were respectively assembled into lithium secondary batteries and numbered accordingly, and then capacity retention rates of the lithium secondary batteries at 25 ℃ (2C/1C current density) and 45 ℃ (2C/1C current density) by 1000 cycles, capacity retention rates at 60 ℃ for 15 days, capacity recovery rates and expansion rates, and rate performance (including rate discharge performance and rate charge performance) were respectively tested.
Wherein the content of the first and second substances,
the lithium secondary battery was assembled as follows:
s1, according to 97:1:1: liNi mixed at a mass ratio of 1 0.6 Co 0.1 Mn 0.3 O 2 Dispersing (positive electrode active material), super P, carbon nano tubes (conductive agent) and polyvinylidene fluoride (binder) in N-methyl-2-pyrrolidone to obtain positive electrode slurry; then, the positive electrode slurry was uniformly coated on both sides of the aluminum foil (coating weight: 250 g/m) 2 ) Drying at 85 ℃ and then carrying out cold pressing; then, trimming, cutting into pieces, slitting, and drying for 4 hours at 85 ℃ under a vacuum condition after slitting; and then welding the tab to obtain the positive plate.
S2, according to a 95:1.5:1:2.5, mixing graphite (a negative electrode active material), super P (a conductive agent), CMC (a thickening agent) and styrene butadiene rubber emulsion (a binder) in a mass ratio, and dispersing in deionized water to obtain negative electrode slurry; then, coating the negative electrode slurry on two sides of the copper foil; and then, drying, rolling and vacuum drying are sequentially carried out, and a nickel lead wire is welded on the nickel lead wire by an ultrasonic welding machine to obtain the negative plate.
S3, sequentially stacking the prepared positive plate, the diaphragm (the PE is coated with the ceramic diaphragm, the thickness is 20 microns) and the negative plate, and winding to prepare a bare cell, then injecting the bare cell, the shell and the battery electrolyte group prepared in the examples 1-15 and the comparative examples 1-10 into the dried battery, and carrying out packaging, standing, formation, shaping and capacity test to obtain the lithium secondary battery.
The test of the corresponding electrical parameters of the lithium secondary battery and the corresponding calculation formula are as follows:
capacity retention test of battery at 25 ℃ cycling for 1000 weeks: charging at 25 deg.C under 2.0C constant current to 4.5V and constant voltage of 4.5V to 0.05C cut-off current, and discharging at 1.0C constant current to obtain a first discharge capacity C 0 Repeating the charge and discharge for 1000 weeks to obtain a 1000 th week discharge capacity C 1000 。
Capacity retention test of battery at 45 ℃ cycling 1000 weeks: charging at 45 deg.C under constant current of 2.0C to 4.5V, charging at constant voltage of 4.5V to cutoff current of 0.05C, and discharging at constant current of 1.0C to obtain discharge capacity C 0 Repeating the charge and discharge for 1000 weeks to obtain a discharge capacity C at 1000 weeks 1000 。
Thickness expansion rate, capacity retention rate and capacity recovery rate test of the battery stored at 60 ℃ for 15 days: the initial thickness and initial capacity of the battery were tested and recorded, and the battery was charged at 60 ℃ to 4.5V at a constant current of 1.0C, charged at a constant voltage of 4.5V to a cutoff current of 0.05C, then discharged at a constant current of 1.0C, then placed in a 60 ℃ explosion-proof oven, stored for 15 days, and tested for thickness by heat in the oven, after which the battery was taken out and cooled to room temperature, and then tested for discharge retention capacity and recovery capacity by discharging to 2.75V using a current of 1C.
And (3) battery rate performance test: and (3) a multiplying power discharge test, namely charging the battery to 4.5V at a constant current of 1.0C and charging the battery to a constant voltage of 4.5V at a temperature of 25 ℃ until the cut-off current is 0.05C, then discharging the battery at a constant current of 1.0C, and recording the first discharge capacity as C 0 Then repeating the above charging step, discharging to 2.75V at constant current of 4.0C, and the second discharge capacity is C 2 (ii) a Multiplying power charging test, charging to 4.5V at 25 deg.C with 1.0C constant current, recording charging capacity as C 3 Then discharged to 2.75V at a constant current of 1.0C, then charged to 4.5V at a constant current of 4.0C, and the charge capacity was recorded as C 4 。
It should be noted that the process parameters and steps not involved in the testing process can be set according to the conventional requirements in the art.
The calculation formula is as follows:
capacity retention (%) at 1000 cycles = (1000 th discharge retention capacity/1 st cycle discharge capacity) × 100%;
capacity recovery (%) = recovery capacity/initial capacity × 100%;
storage capacity retention (%) = retention capacity/initial capacity × 100%;
thickness expansion (%) = (hot thickness-initial thickness)/initial thickness × 100%;
rate charge capacity retention (%) = (4.0C charge capacity)/1.0C charge capacity × 100%;
rate discharge capacity retention (%) = (4.0C discharge capacity)/1.0C discharge capacity × 100%.
Table 2 results of battery performance test of examples and comparative examples
Referring to tables 1 and 2, it can be seen from the test results of examples 1 to 5 and examples 6 to 9 that when BTTN/CTTN and TMSB/TMSP are used in combination, most of the rate capability, cycle capability and storage capability of the corresponding battery at high temperature and high pressure are better than when BTTN/CTTN and TMSB/TMSP are partially replaced with the same type of material.
From the test results of examples 1 to 5 and comparative examples 6 to 10, it can be seen that when BTTN/CTTN and TMSB/TMSP are used in combination, most of the rate capability, cycle capability and storage capability of the battery at high temperature and high pressure are better than when BTTN/CTTN and TMSB/TMSP are all replaced with the same type of material.
From the test results of examples 1 to 5 and comparative examples 1 to 5, it is understood that when BTTN/CTTN and TMSB/TMSP are used in combination, most of the rate performance, cycle performance and storage performance at high temperature and high pressure of the corresponding battery are better than when BTTN/CTTN or TMSB/TMSP is used alone.
From the test results of examples 1 to 5 and examples 11 to 15, it is understood that when the amounts of BTTN/CTTN and TMSB/TMSP are within the ranges, the batteries corresponding to the above are superior in most of rate performance, cycle performance and storage performance at high temperature and high pressure, compared to when the amounts of BTTN/CTTN and TMSB/TMSP are outside the ranges.
The embodiments described above are some, but not all embodiments of the present application. The detailed description of the embodiments of the present application is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without making any creative effort belong to the protection scope of the present application.
Claims (10)
1. A lithium secondary battery electrolyte, wherein an additive in the lithium secondary battery electrolyte comprises: tetracyanoalkoxy aliphatic straight-chain alkane with a structural formula shown as a formula I and/or a formula II; and tris (trimethylsilane) borate and/or tris (trimethylsilane) phosphite;
the formula I is shown as follows:
the formula II is shown below:
2. the electrolyte for a lithium secondary battery according to claim 1, wherein the additive is contained in the electrolyte for a lithium secondary battery in an amount of 0.6 to 7% by mass.
3. The electrolyte for a lithium secondary battery according to claim 2, wherein the mass percentage of the tetracyanoalkoxyaliphatic linear alkane is 0.5 to 4%, and the mass percentage of the tris (trimethylsilyl) borate and/or the tris (trimethylsilyl) phosphite is 0.1 to 3%.
4. The lithium secondary battery electrolyte according to any one of claims 1 to 3, wherein the organic solvent in the lithium secondary battery electrolyte comprises at least one of a cyclic carbonate, a chain carbonate, and a carboxylate.
5. The lithium secondary battery electrolyte according to claim 4, wherein at least one of the following conditions A to C is satisfied:
a, the cyclic carbonate comprises at least one of ethylene carbonate, fluoroethylene carbonate and propylene carbonate;
b, the chain carbonate comprises at least one of dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate;
c, the carboxylic ester comprises at least one of propyl acetate, ethyl acetate and propyl propionate.
6. The lithium secondary battery electrolyte according to any one of claims 1 to 3, wherein the lithium salt in the lithium secondary battery electrolyte comprises LiPF 6 、LiBF 4 、LiB(C 2 O 4 ) 2 、LiBF 2 C 2 O 4 、LiN(SO 2 F) 2 And LiN (SO) 2 CF 3 ) 2 At least one of (1).
7. The lithium secondary battery electrolyte according to claim 6, wherein the mass percentage of the lithium salt in the lithium secondary battery electrolyte is 0.5 to 20%.
8. A lithium secondary battery, characterized by comprising;
a housing;
an electrode assembly housed within the case; and
the lithium secondary battery electrolyte as claimed in any one of claims 1 to 7 which is contained within the case.
9. The lithium secondary battery of claim 8, wherein in the electrode assembly, the positive active material comprises LiNi x Co y Mn z O 2 Wherein x + y + z =1.
10. An electric device characterized by comprising the lithium secondary battery according to claim 8 or 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211526957.0A CN115799636B (en) | 2022-11-30 | 2022-11-30 | Lithium secondary battery electrolyte, lithium secondary battery and electric equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211526957.0A CN115799636B (en) | 2022-11-30 | 2022-11-30 | Lithium secondary battery electrolyte, lithium secondary battery and electric equipment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115799636A true CN115799636A (en) | 2023-03-14 |
| CN115799636B CN115799636B (en) | 2023-09-26 |
Family
ID=85444281
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211526957.0A Active CN115799636B (en) | 2022-11-30 | 2022-11-30 | Lithium secondary battery electrolyte, lithium secondary battery and electric equipment |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115799636B (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103107359A (en) * | 2011-11-15 | 2013-05-15 | 首尔步瑞株式会社 | Electrolyte solution for a lithium secondary battery and lithium secondary battery comprising the same |
| JP2016134406A (en) * | 2015-01-16 | 2016-07-25 | 宇部興産株式会社 | Carboxylic acid compound useful as solute for electrolyte for power storage device and method for producing the same |
| CN106033824A (en) * | 2015-03-18 | 2016-10-19 | 宁德时代新能源科技股份有限公司 | High-voltage lithium ion battery and electrolyte thereof |
| CN107978759A (en) * | 2017-12-01 | 2018-05-01 | 中航锂电（洛阳）有限公司 | A kind of used as negative electrode of Li-ion battery combined conductive agent and preparation method, negative electrode of lithium ion battery and lithium ion battery |
| CN112151868A (en) * | 2020-10-26 | 2020-12-29 | 珠海冠宇电池股份有限公司 | Electrolyte for lithium secondary battery and lithium secondary battery comprising same |
| CN112768772A (en) * | 2021-02-22 | 2021-05-07 | 广州天赐高新材料股份有限公司 | Nitrile ether electrolyte additive containing tetracyano, electrolyte and lithium ion battery |
| CN113130988A (en) * | 2019-12-30 | 2021-07-16 | 深圳市研一新材料有限责任公司 | Electrolyte and electrochemical device using same |
-
2022
- 2022-11-30 CN CN202211526957.0A patent/CN115799636B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103107359A (en) * | 2011-11-15 | 2013-05-15 | 首尔步瑞株式会社 | Electrolyte solution for a lithium secondary battery and lithium secondary battery comprising the same |
| JP2016134406A (en) * | 2015-01-16 | 2016-07-25 | 宇部興産株式会社 | Carboxylic acid compound useful as solute for electrolyte for power storage device and method for producing the same |
| CN106033824A (en) * | 2015-03-18 | 2016-10-19 | 宁德时代新能源科技股份有限公司 | High-voltage lithium ion battery and electrolyte thereof |
| CN107978759A (en) * | 2017-12-01 | 2018-05-01 | 中航锂电（洛阳）有限公司 | A kind of used as negative electrode of Li-ion battery combined conductive agent and preparation method, negative electrode of lithium ion battery and lithium ion battery |
| CN113130988A (en) * | 2019-12-30 | 2021-07-16 | 深圳市研一新材料有限责任公司 | Electrolyte and electrochemical device using same |
| CN112151868A (en) * | 2020-10-26 | 2020-12-29 | 珠海冠宇电池股份有限公司 | Electrolyte for lithium secondary battery and lithium secondary battery comprising same |
| CN112768772A (en) * | 2021-02-22 | 2021-05-07 | 广州天赐高新材料股份有限公司 | Nitrile ether electrolyte additive containing tetracyano, electrolyte and lithium ion battery |
Non-Patent Citations (2)
| Title |
|---|
| SHENG SHUI ZHANG: "A review on electrolyte additives for lithium-ion batteries", 《JOURNAL OF POWER SOURCES》, vol. 162, no. 2, pages 1379 - 1394, XP055557116, DOI: 10.1016/j.jpowsour.2006.07.074 * |
| 李春雷 等: "锂离子电池中SEI 膜组成与改性的研究进展", 《电源技术》, vol. 40, no. 10, pages 2079 - 2081 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115799636B (en) | 2023-09-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109921092B (en) | Non-aqueous electrolyte of silicon-based negative electrode lithium ion battery and silicon-based negative electrode lithium ion battery containing electrolyte | |
| CN107359369B (en) | Electrolyte and lithium ion battery | |
| CN110970621B (en) | Lithium ion battery | |
| CN111640985A (en) | Non-aqueous electrolyte and high-voltage lithium ion battery containing same | |
| CN110931865A (en) | Novel additive-containing electrolyte for lithium ion battery and lithium ion battery | |
| CN112467211A (en) | Electrolyte additive, electrolyte and silicon-carbon negative electrode lithium ion battery | |
| CN112216862A (en) | High-nickel ternary lithium ion battery electrolyte and ternary lithium ion battery | |
| CN111525192A (en) | Lithium ion battery non-aqueous electrolyte and lithium ion battery | |
| EP3996180A1 (en) | Electrolytic solution, and preparation method therefor and application thereof | |
| CN115775908A (en) | High-nickel ternary lithium ion battery electrolyte and lithium ion battery containing same | |
| CN115332628A (en) | Lithium ion battery electrolyte, lithium ion battery and electric equipment | |
| CN115911560A (en) | Electrolyte, secondary battery and electric equipment | |
| CN112290090A (en) | High-nickel ternary lithium ion battery non-aqueous electrolyte and battery containing electrolyte | |
| CN114069047A (en) | High-voltage-resistant lithium secondary battery electrolyte and lithium secondary battery | |
| CN112086684B (en) | Cesium-containing high-voltage lithium ion battery electrolyte composite additive, electrolyte and battery thereof | |
| CN117423904A (en) | Electrolyte and battery | |
| CN111430781A (en) | Ternary high-voltage lithium ion battery electrolyte and lithium ion battery thereof | |
| CN116646598A (en) | Electrolyte and secondary battery | |
| CN117480655A (en) | Electrochemical device and electronic device | |
| CN115332626A (en) | Electrolyte and battery comprising same | |
| CN115799636B (en) | Lithium secondary battery electrolyte, lithium secondary battery and electric equipment | |
| CN114583268A (en) | Lithium ion battery electrolyte and application thereof | |
| CN113328144A (en) | Lithium ion battery electrolyte and lithium ion battery using same | |
| CN112582672A (en) | Ternary lithium ion battery non-aqueous electrolyte and ternary lithium ion battery containing same | |
| CN110994021A (en) | Electrolyte additive, electrolyte and lithium ion battery |
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 |