CN116154280B - Gel electrolyte of lithium battery and application thereof - Google Patents
Gel electrolyte of lithium battery and application thereof Download PDFInfo
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- CN116154280B CN116154280B CN202310436370.9A CN202310436370A CN116154280B CN 116154280 B CN116154280 B CN 116154280B CN 202310436370 A CN202310436370 A CN 202310436370A CN 116154280 B CN116154280 B CN 116154280B
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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
- H01M10/0565—Polymeric materials, e.g. gel-type or solid-type
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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
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
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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
- H01M10/42—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
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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
- H01M2300/00—Electrolytes
- H01M2300/0017—Non-aqueous electrolytes
- H01M2300/0065—Solid electrolytes
- H01M2300/0082—Organic polymers
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- 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
Abstract
The invention provides a gel electrolyte of a lithium battery and application thereof, wherein the gel electrolyte at least comprises the following components: an organic solvent; a lithium salt; and a functional additive comprising one or more of ethyl 4-dihydropyrimidin-2-yl ureido methacrylate, 2, 3-pentafluoropropyl acrylate, or pentaerythritol tetraacrylate. The invention provides a gel electrolyte of a lithium battery and application thereof, which can improve the cycle performance of the lithium ion battery.
Description
Technical Field
The invention relates to the technical field of lithium ion batteries, in particular to a gel electrolyte of a lithium battery and application thereof.
Background
Lithium ion batteries using graphite and lithium titanate as negative electrodes in commerce gradually approach to the limit of energy density, and the requirements of new generation energy storage devices cannot be met. Lithium metal has extremely high theoretical specific capacity, lower electrochemical potential and extremely low mass density, and is hopefully applied to the fields of lithium secondary batteries, lithium sulfur batteries, lithium air batteries and the like instead of graphite cathodes.
In a lithium battery with an electrolyte structure, there are problems of flammability, volatility, corrosion and leakage, and the like, and lithium metal negative electrodes are attracting attention due to their high energy density and high safety when applied to solid-state batteries. However, when the solid electrolyte is matched with a lithium metal negative electrode, the problem of serious lithium dendrite penetration exists, and meanwhile, the problems of short circuit, poor interface stability, poor cycle performance and the like are easy to occur due to poor contact between the electrode and the electrolyte. The gel electrolyte has excellent electrochemical stability and safety, and can inhibit the growth of lithium dendrite to a certain extent, but also has obvious interface problem, thereby affecting the capacity exertion and the rate performance of the battery.
Disclosure of Invention
The gel electrolyte of the lithium battery and the application thereof provided by the invention have the self-repairing function, and can effectively repair gaps and cracks generated by the gel electrolyte, so that the cycle performance of the lithium battery is improved.
In order to solve the technical problems, the invention is realized by the following technical scheme.
The invention provides a gel electrolyte of a lithium battery, which at least comprises the following components:
an organic solvent;
a lithium salt; and
functional additives including one or more of ethyl 4-dihydropyrimidin-2-yl ureido methacrylate, 2, 3-pentafluoropropyl acrylate, or pentaerythritol tetraacrylate.
In one embodiment of the invention, the functional additive is present in the electrolyte in an amount of 0.5wt% to 10wt%.
In one embodiment of the present invention, the mass ratio of the 4-dihydropyrimidin-2-yl ureido methacrylate to the 2, 3-pentafluoropropyl acrylate is 1:1-3:1.
in one embodiment of the present invention, the mass ratio of the 4-dihydropyrimidin-2-yl ureido methacrylate to the pentaerythritol tetraacrylate is 3:1-10:1.
in an embodiment of the present invention, the mass ratio of the 2, 3-pentafluoropropyl acrylate to the pentaerythritol tetraacrylate is 5:1-10:1.
in another embodiment of the present invention, the functional additive is the 4-dihydropyrimidin-2-yl ureido ethyl methacrylate, and the mass content of the 4-dihydropyrimidin-2-yl ureido ethyl methacrylate in the electrolyte is 0.5wt% to 10wt%.
In one embodiment of the invention, the electrolyte further comprises a negative electrode film-forming additive, wherein the mass content of the negative electrode film-forming additive in the electrolyte is 0.5wt% to 5wt%.
In one embodiment of the present invention, the negative film-forming additive comprises one or more of 1,3-propane sultone, vinylene carbonate, fluoroethylene carbonate, vinyl sulfate, or lithium difluorophosphate.
In an embodiment of the present invention, the mass content of the lithium salt in the electrolyte is 8wt% to 15wt%, and the lithium salt includes one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis (fluorosulfonyl) imide, lithium bis (trifluoromethanesulfonyl) imide, or lithium bis (oxalato) borate.
In an embodiment of the present invention, the mass content of the organic solvent in the electrolyte is 70wt% to 91wt%, and the organic solvent includes one or more of dimethyl carbonate, methylethyl carbonate, ethylene carbonate, propylene carbonate, or diethyl carbonate.
In an embodiment of the present invention, the organic solvent is a mixture of the dimethyl carbonate, the ethylmethyl carbonate and the ethylene carbonate, and the mass ratio of the ethylene carbonate, the ethylmethyl carbonate and the dimethyl carbonate is 3: (4-7): 3.
the invention also provides a lithium ion battery comprising the gel electrolyte.
The invention also provides an electrochemical device comprising the lithium ion battery.
In summary, the invention provides a gel electrolyte of a lithium battery and application thereof, which has a self-repairing function and can spontaneously repair gaps and cracks generated by the gel electrolyte, so that positive and negative electrodes are always in effective contact with the gel electrolyte, and performance degradation caused by partial poor contact is avoided. The self-repairing efficiency can be further improved, so that the cycle performance of the lithium battery is improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic structural diagram of a lithium ion battery according to the present invention.
Fig. 2 is a composition ratio chart of components in the gel electrolyte of each example and each comparative example in the present invention.
Fig. 3 is a graph showing cycle performance of lithium batteries of examples and comparative examples in the present invention.
Description of the reference numerals: 10. a positive electrode; 20. a negative electrode; 30. a diaphragm; 40. gel electrolyte.
Detailed Description
Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention.
It should be understood that the present invention may be embodied in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
The technical solution of the present invention will be described in further detail below with reference to several embodiments and the accompanying drawings, and it is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The energy density of the all-solid-state lithium battery is expected to be 2-5 times that of the existing commercial lithium ion battery, and the safety problem of the existing liquid electrolyte lithium ion battery can be solved essentially, so that the lithium ion battery becomes the research focus of the next generation lithium battery. The gel electrolyte of the lithium battery and the application thereof provided by the invention can fully exert the potential of the lithium battery in energy density, and are expected to be applied to the fields of various electronic products, electric vehicles and the like.
The invention provides a gel electrolyte of a lithium battery, which comprises organic solvent, lithium salt, functional additives and the like. Wherein the functional additive comprises one or more of 4-dihydropyrimidine-2-yl ureido ethyl methacrylate (UpyMA), 2, 3-pentafluoropropyl acrylate (PFE) or pentaerythritol tetraacrylate (Pentaerythritol Tetraacrylate, PETA) and the like. Wherein 4-dihydropyrimidin-2-yl ureido ethyl methacrylate is a Monomer (4-H-bond Monomer) containing 4-fold hydrogen bond, 4-dihydropyrimidin-2-yl ureido ethyl methacrylate is defined as 4HM in the present invention.
In one embodiment of the invention, the functional additive is present in the gel electrolyte in an amount of, for example, 0.5wt% to 10wt%, and further, the ethyl 4-dihydropyrimidin-2-yl ureido methacrylate is present in the gel electrolyte in an amount of, for example, 0.5wt% to 5wt%. In one embodiment, the functional additive is, for example, ethyl 4-dihydropyrimidin-2-yl ureido methacrylate. In another embodiment, the functional additive is, for example, a mixture of ethyl 4-dihydropyrimidin-2-yl ureido methacrylate, 2, 3-pentafluoropropyl acrylate, and pentaerythritol tetraacrylate. Wherein the mass ratio of the 4-dihydropyrimidin-2-yl ureido ethyl methacrylate to the 2, 3-pentafluoropropyl acrylate is, for example, 1:1-3: the mass ratio of the ethyl 1, 4-dihydropyrimidin-2-yl ureido methacrylate to the pentaerythritol tetraacrylate is, for example, 3:1-10:1, and the mass ratio of 2, 3-pentafluoropropyl acrylate to pentaerythritol tetraacrylate is for example 5:1-10:1. the structural formula of the 4-dihydropyrimidin-2-yl ureido ethyl methacrylate is as follows:due to the presence of quadruple hydrogen bond structure in 4-dihydropyrimidin-2-yl ureido ethyl methacrylate, when the gel electrolyte is destroyed, the 4-dihydropyrimidin-2-yl ureido ethyl methacrylate can form intermolecular hydrogen bonds, thereby partially crosslinking the gel electrolyte toRealizing the self-repairing effect. Furthermore, the combined use of 2, 3-pentafluoropropyl acrylate and pentaerythritol tetraacrylate can increase the strength of the electrolyte membrane, form a self-repairing cross-linked network, and improve the self-repairing efficiency.
In one embodiment of the invention, a negative film-forming additive may also be added to the gel electrolyte, for example. The negative electrode film forming additive capable of promoting film formation is added into the electrolyte, so that a solid electrolyte interface film (Solid Electrolyte Interface, SEI) with a thinner, uniform and compact thickness is formed on the surface of the negative electrode, the SEI film has good electronic insulation, only lithium ions can freely pass through, solvent molecules cannot pass through, the electrolyte and the negative electrode material can be prevented from further reacting, and the electrochemical performance of the negative electrode material is improved. In one embodiment of the present invention, the negative film-forming additive comprises, for example, 1,3-Propane Sultone (PS), vinylene carbonate (Vinylene Carbonate, VC), fluoroethylene carbonate (Fluoroethylene Carbonate, FEC), ethylene Sulfate (DTD), or lithium difluorophosphate (LiPO) 2 F 2 ) And the like, the mass content of the negative electrode film-forming additive in the gel electrolyte is, for example, 0.5wt% to 5wt%.
In one embodiment of the invention, the lithium salt comprises, for example, lithium hexafluorophosphate (LiPF 6 ) Lithium tetrafluoroborate (LiBF) 4 ) Lithium bis (fluorosulfonyl) imide (LiSSI), lithium bis (trifluoromethanesulfonyl) imide (C) 2 F 6 LiNO 4 S 2 ) Or lithium dioxaborate (LiBOB) or the like, and the mass content of the lithium salt in the gel electrolyte is, for example, 8wt% to 15wt%. The organic solvent includes, for example, one or more of dimethyl carbonate (DMC), ethylmethyl carbonate (EMC), ethylene Carbonate (EC), propylene Carbonate (PC), diethyl carbonate (DEC), or the like, and the mass content of the organic solvent in the gel electrolyte is, for example, 70wt% to 91wt%. In the present embodiment, the organic solvent is, for example, a mixture of Ethylene Carbonate (EC), ethylmethyl carbonate (EMC) and dimethyl carbonate (DMC), and the mass ratio of ethylene carbonate, ethylmethyl carbonate and dimethyl carbonate is, for example, 3：（4-7）：3。
Referring to fig. 1, the present invention further provides a lithium ion battery, which includes a positive electrode 10, a separator 30, a negative electrode 20, and the gel electrolyte 40, wherein the separator 30 is located between the positive electrode 10 and the negative electrode 20, and the gel electrolyte 40 is filled between the positive electrode 10, the separator 30, and the negative electrode 20.
Referring to fig. 1, in an embodiment of the present invention, a positive electrode 10 includes, for example, a positive electrode material, a positive electrode current collector, a binder, a conductive agent, a thickener, and the like. The positive electrode current collector is selected from aluminum foil, for example. The binder is selected from, for example, any one or more of polyvinylidene fluoride (Polyvinylidene Fluoride, PVDF), polyamide (Polyamide, PA), polyacrylonitrile (PAN), polyacrylate, polyvinyl ether (polyvinylether), polymethyl methacrylate (Polymethyl Methacrylate, PMMA), polyhexafluoropropylene (Polyhexafluoropropylene), styrene-butadiene rubber (Polymerized Styrene Butadiene Rubber, SBR), and the like. The conductive agent is selected from, for example, any one or more of conductive carbon black (Super P, SP), acetylene black, carbon nanotubes, graphene, and the like. The thickener is selected from one or more of N-Methylpyrrolidone (NMP), sodium carboxymethylcellulose (Carboxymethylcellulose Sodium, CMC-Na) or Sodium Alginate (Sodium Alginate), for example. The positive electrode material is, for example, one or more of Lithium Cobalt Oxide (LCO), lithium Nickel Oxide (LNO), lithium Manganese Oxide (LMO), lithium Nickel Manganese Oxide (LNMO), lithium nickel cobalt manganese oxide (NCM), lithium nickel cobalt aluminum oxide (NCA), or the like.
Referring to fig. 1, in an embodiment of the present invention, the negative electrode 20 includes, for example, a lithium metal material. Examples of the lithium metal material include lithium metal foil, copper lithium metal strip, and the like. In another embodiment of the present invention, the negative electrode 20 includes, for example, a negative electrode current collector, a negative electrode material, a binder, a conductive agent, a thickener, and the like. The negative electrode current collector is selected from copper foil, for example. The negative electrode material is selected from, for example, a graphite-based material, a silicon-based material, or a composite material of a graphite material and a silicon-based material. The graphite-based material is, for example, any one or more of natural graphite, artificial graphite, crystalline carbon, amorphous carbon, or a carbon composite material. The silicon-based material is, for example, elemental silicon and/or silicon oxide. The binder is selected from, for example, any one or more of polyvinylidene fluoride (Polyvinylidene Fluoride, PVDF), polyamide (Polyamide, PA), polyacrylonitrile (PAN), polyacrylate, polyvinyl ether (polyvinylether), polymethyl methacrylate (Polymethyl Methacrylate, PMMA), polyhexafluoropropylene (Polyhexafluoropropylene), styrene-butadiene rubber (Polymerized Styrene Butadiene Rubber, SBR), and the like. The conductive agent is selected from, for example, any one or more of conductive carbon black (Super P, SP), acetylene black, carbon nanotubes, graphene, and the like. The thickener is selected from one or more of N-Methylpyrrolidone (NMP), sodium carboxymethylcellulose (Carboxymethylcellulose Sodium, CMC-Na) or Sodium Alginate (Sodium Alginate), for example.
Referring to fig. 1, in an embodiment of the present invention, the separator 30 may be selected from Polyethylene (PE) or Polypropylene (PP) films, and the thickness of the separator 30 is, for example, 10 μm-15 μm. In an embodiment of the present invention, the positive electrode 10, the separator 30, and the negative electrode 20 are laminated in order, so that the separator 30 is located between the positive electrode 10 and the negative electrode 20 to perform a separation function.
Hereinafter, the present invention will be more specifically explained by referring to examples, which should not be construed as limiting. Appropriate modifications may be made within the scope consistent with the gist of the invention, which fall within the technical scope of the invention.
Example 1
Preparation of gel electrolyte: EC, EMC and DMC were mixed as 3:4:3, wherein the negative film-forming additive is selected from FEC, the lithium salt is selected from LiFSI, the functional additive is selected from 4HM, and 81.5wt% of the organic solvent, 5wt% of FEC, 13wt% of LiFSI and 0.5wt% of 4HM are mixed to obtain the gel electrolyte 40.
Preparation of positive electrode: 97wt% of LiNi 0.8 Co 0.1 Mn 0.1 O 2 2wt% carbon black and 1wt% PVDF were added to NMP to prepare a positive electrode slurry. The positive electrode slurry is preparedCoated on an aluminum foil of 13 μm and dried, and then roll die-cut to prepare the positive electrode 10.
Preparation of the negative electrode: a 30 μm copper-lithium composite tape was selected as the negative electrode, and the negative electrode 20 was prepared by dry internal die cutting.
Preparation of a lithium battery: the above-described positive electrode 10 and negative electrode 20 were laminated with a separator 30 formed of three layers of PP/PE/PP to prepare a pouch battery, after which the above-described gel electrolyte 40 was injected, followed by formation, capacity division and aging, and the manufacture of a lithium ion battery was completed.
Example 2
The procedure was as in example 1 except that 81.5wt% of the organic solvent was changed to 77wt% of the organic solvent, and 0.5wt% of the 4HM was changed to 5wt% of the 4HM.
Example 3
The procedure was as in example 1 except that 81.5wt% of the organic solvent was changed to 79.5wt% of the organic solvent, and 0.5wt% of the 4HM was changed to 2.5wt% of the 4HM.
Example 4
Other operations remain consistent with example 1, changing 81.5wt% organic solvent to 76.9wt% organic solvent, changing 0.5wt% 4HM to a mixture of 5.0wt% 4HM, 2.5wt% PFE, and 0.5wt% PETA.
Example 5
Other operations remain consistent with example 1, changing 81.5wt% organic solvent to 76.75wt% organic solvent, changing 0.5wt% 4HM to a mixture of 2.5wt% 4HM, 2.5wt% PFE, and 0.25wt% PETA.
Example 6
Other operations remain consistent with example 1, changing 81.5wt% organic solvent to 76.5wt% organic solvent, changing 0.5wt% 4HM to a mixture of 2.5wt% 4HM, 2.5wt% PFE, and 0.5wt% PETA.
Example 7
Other operations remain consistent with example 1, changing 81.5wt% organic solvent to 74wt% organic solvent, changing 0.5wt% 4HM to a mixture of 6.0wt% 4HM, 2.0wt% PFE, and 0.4wt% PETA.
Comparative example 1
Functional additives were not added to the gel electrolyte, and other operations were consistent with example 1.
Comparative example 2
The procedure was as in example 1 except that 81.5wt% of the organic solvent was changed to 81.9wt% of the organic solvent, and 0.5wt% of the 4HM was changed to 0.1wt% of the 4HM.
Comparative example 3
The procedure was as in example 1 except that 81.5wt% of the organic solvent was changed to 72wt% of the organic solvent, and 0.5wt% of the 4HM was changed to 10wt% of the 4HM.
Comparative example 4
Other operations remain consistent with example 1, changing 81.5wt% organic solvent to 81.35wt% organic solvent, changing 0.5wt% 4HM to a mixture of 0.3wt% 4HM, 0.3wt% PFE, and 0.05wt% PETA.
Comparative example 5
The organic solvent of 81.5wt% is changed to 67wt% and the amount of the functional additive is changed to 15wt%, wherein 4HM: PFE: the mass ratio of PETA is 30:30:5, the other operations remain the same as in example 1.
The raw materials and proportions of the gel electrolytes in examples 1 to 7 and comparative examples 1 to 5 in the present invention were adjusted, and the raw material formulations in each example and each comparative example were prepared as shown in fig. 2.
The gel electrolyte is then used to prepare a lithium battery by the preparation method, and the cycle performance of the lithium battery is tested, and the test result is shown in fig. 3.
The normal temperature cycle test is to circularly charge and discharge the prepared lithium battery at 25 ℃, measure the capacity retention rate, and the voltage interval is 2.8V-4.35V, the charging multiplying power is 1C, and the discharging multiplying power is 1C.
Referring to fig. 2 and 3, in comparative example 1, the gel electrolyte was not added with a functional additive such as 4HM, and the lithium battery was short-circuited only by cycling for 30 cycles. This is because the volume change of the anode causes generation of voids, cracks in the electrolyte, incomplete contact between the anode and the cathode and even precipitation of lithium or generation of lithium dendrites, etc., which eventually cause short circuit of the lithium battery. In comparative example 2, 0.1wt% of 4HM was added to the gel electrolyte as a functional additive, and a short circuit occurred in the lithium battery for 52 cycles of charge and discharge. In examples 1 to 3, when 0.5wt% to 5wt% of 4HM was added as a functional additive to the gel electrolyte and the addition amount of 4HM was in the range of 0.5wt% to 2.5wt%, the number of cycles of charge and discharge of the lithium battery was gradually increased up to 301 as the content of 4HM was increased. However, in comparative example 3, the cycle charge-discharge number of the lithium battery was reduced to 221 cycles when the 4HM content was increased to 10wt%. It can be seen from the combination of comparative examples 1 to 3 and examples 1 to 3 that the structure in which a proper amount of 4HM,4HM is introduced into the gel electrolyte contains four hydrogen bonds, and after polymerization is initiated by lithium metal, lithium silicon alloy or lithium intercalated graphite in the formation process, the electrolyte is partially crosslinked, and gaps and cracks generated by the gel electrolyte can be spontaneously repaired, so that the positive and negative electrodes are always kept in effective contact with the gel electrolyte, and the performance deterioration caused by partial contact failure is avoided. And when the content of 4HM is too high and more than 5wt%, 4HM is polymerized to form a dense crosslinked network, thereby suppressing the transport of lithium ions, resulting in degradation of the performance of the lithium battery.
Referring to fig. 2 and 3, in examples 4 to 7, after 4HM was introduced into the gel electrolyte, and PFE and PETA were used as functional additives together, the number of cycles of charge and discharge of the lithium battery was further increased up to 432 cycles. The 4HM is combined with the PFE and the PETA, and the mass ratio of the 4HM to the PFE to the PETA is in the range of (30:30:10) - (30:10:3), so that the strength of the electrolyte membrane can be increased, a self-repairing cross-linked network is formed, the self-repairing efficiency is further improved, and the cycle performance of the lithium battery is improved. In comparative example 4, when 0.3wt% of 4HM, 0.3wt% of PFE and 0.05wt% of PETA were mixed to constitute the functional additive, and the mass ratio of 4HM, PFE and PETA was 30:30: and 5, the cycle performance of the lithium battery is not greatly improved. In comparative example 5, the mass ratio of 4HM, PFE and PETA is 30:30:5, and the total content of the functional additives is too high and above 10wt%, the lithium battery cannot be recycled. By combining examples 4-7 and comparative examples 4-5, after 4HM was introduced into the gel electrolyte and used in combination with PFE and PETA, the total content of functional additives was in the range of 0.5wt% to 10wt%, and the cycle performance of the lithium battery was greatly improved. Further, when the content of 4HM is in the range of 0.5wt% to 5wt%, the cycle performance of the lithium battery is optimal. And when the mass ratio of PFE to PETA is 5:1-10:1, the 4HM has the best synergistic effect with the PFE and the PETA, and the repair effect on gaps and cracks generated by the gel electrolyte is the best, so that the lithium battery has the best cycle performance.
In summary, the invention provides a gel electrolyte of a lithium battery and application thereof, wherein 4-dihydropyrimidine-2-yl ureido ethyl methacrylate is introduced into the gel electrolyte as a functional additive, the structure of the 4-dihydropyrimidine-2-yl ureido ethyl methacrylate contains quadruple hydrogen bonds, and after polymerization is initiated by lithium metal, lithium silicon alloy or lithium-intercalated graphite in the formation process, the electrolyte is partially crosslinked, and gaps and cracks generated by the gel electrolyte can be spontaneously repaired, so that positive and negative electrodes are always kept in effective contact with the gel electrolyte, and performance degradation caused by partial poor contact is avoided. And 4-dihydropyrimidin-2-yl ureido ethyl methacrylate is further used in combination with 2, 3-pentafluoropropyl acrylate and pentaerythritol tetraacrylate, and the mass ratio of the 2, 3-pentafluoropropyl acrylic ester to the pentaerythritol tetraacrylate is regulated and controlled, the self-repairing cross-linked network can be formed while the strength of the electrolyte membrane is enhanced, the self-repairing efficiency is improved, and the lithium battery has the best cycle performance.
The foregoing description is only illustrative of the preferred embodiments of the present application and the technical principles employed, and it should be understood by those skilled in the art that the scope of the invention in question is not limited to the specific combination of features described above, but encompasses other technical solutions which may be formed by any combination of features described above or their equivalents without departing from the inventive concept, such as the features described above and the features disclosed in the present application (but not limited to) having similar functions being interchanged.
Other technical features besides those described in the specification are known to those skilled in the art, and are not described herein in detail to highlight the innovative features of the present invention.
Claims (8)
1. A gel electrolyte for a lithium battery, comprising at least the following components:
an organic solvent;
a lithium salt; and
functional additives comprising 4-dihydropyrimidin-2-yl ureido ethyl methacrylate, 2, 3-pentafluoropropyl acrylate and pentaerythritol tetraacrylate, wherein the structural formula of the 4-dihydropyrimidin-2-yl ureido ethyl methacrylate is as follows:；
wherein the mass content of the functional additive in the electrolyte is 0.5-10wt%, the mass content of the 4-dihydropyrimidine-2-yl ureido ethyl methacrylate in the electrolyte is 0.5-5wt%, and the mass ratio of the 4-dihydropyrimidine-2-yl ureido ethyl methacrylate to the 2, 3-pentafluoropropyl acrylate is 1:1-3:1, wherein the mass ratio of the 4-dihydropyrimidine-2-yl ureido ethyl methacrylate to the pentaerythritol tetraacrylate is 3:1-10:1, wherein the mass ratio of the 2, 3-pentafluoropropyl acrylate to the pentaerythritol tetraacrylate is 5:1-10:1.
2. the gel electrolyte of a lithium battery according to claim 1, wherein the electrolyte further comprises a negative electrode film-forming additive, and the mass content of the negative electrode film-forming additive in the electrolyte is 0.5wt% to 5wt%.
3. The gel electrolyte of claim 2, wherein the negative film-forming additive comprises one or more of 1,3-propane sultone, vinylene carbonate, fluoroethylene carbonate, vinyl sulfate, or lithium difluorophosphate.
4. The gel electrolyte of a lithium battery according to claim 1, wherein the mass content of the lithium salt in the electrolyte is 8wt% to 15wt%, and the lithium salt comprises one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis (fluorosulfonyl) imide, lithium bis (trifluoromethanesulfonyl) imide, or lithium bis (oxalato) borate.
5. The gel electrolyte of a lithium battery according to claim 1, wherein the mass content of the organic solvent in the electrolyte is 70wt% to 91wt%, and the organic solvent comprises one or more of dimethyl carbonate, methylethyl carbonate, ethylene carbonate, propylene carbonate, or diethyl carbonate.
6. The gel electrolyte of a lithium battery according to claim 5, wherein the organic solvent is a mixture of the dimethyl carbonate, the ethylmethyl carbonate and the ethylene carbonate, and the mass ratio of the ethylene carbonate, the ethylmethyl carbonate and the dimethyl carbonate is 3: (4-7): 3.
7. a lithium ion battery comprising a gel electrolyte according to any one of claims 1-6.
8. An electrochemical device comprising the lithium-ion battery according to claim 7.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310436370.9A CN116154280B (en) | 2023-04-23 | 2023-04-23 | Gel electrolyte of lithium battery and application thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310436370.9A CN116154280B (en) | 2023-04-23 | 2023-04-23 | Gel electrolyte of lithium battery and application thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN116154280A CN116154280A (en) | 2023-05-23 |
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| CN110867613A (en) * | 2019-11-19 | 2020-03-06 | 凌帕新能源科技(上海)有限公司 | Silicon-carbon negative electrode lithium ion battery electrolyte and lithium battery |
| CN110911753A (en) * | 2019-12-13 | 2020-03-24 | 东莞东阳光科研发有限公司 | Non-aqueous electrolyte and lithium ion battery |
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| CN108110315B (en) * | 2017-12-08 | 2019-12-31 | 河北师范大学 | Preparation method of self-repairing polymer electrolyte of lithium ion battery |
| WO2021086485A1 (en) * | 2019-10-31 | 2021-05-06 | The Board Of Trustees Of The Leland Stanford Junior University | Liquid and solid electrolytes with lithium-fluorine solvation structure for lithium batteries |
| CN111029647B (en) * | 2019-12-20 | 2023-07-18 | 中国电子科技集团公司第十八研究所 | Preparation method of electrolyte with self-repairing function and solid-state battery |
| CN111653827B (en) * | 2020-05-28 | 2021-08-31 | 远景动力技术(江苏)有限公司 | Electrolyte of lithium ion battery and lithium ion battery |
| CN112481829A (en) * | 2020-11-16 | 2021-03-12 | 华中科技大学 | Single-ion conductor polymer electrolyte composite diaphragm, and preparation method and application thereof |
| CN113506917A (en) * | 2021-06-29 | 2021-10-15 | 五邑大学 | Preparation method of self-repairing polymer electrolyte of lithium ion battery |
| CN114400374B (en) * | 2021-12-21 | 2023-08-18 | 中国科学院苏州纳米技术与纳米仿生研究所 | Polymer electrolyte, all-solid-state high-voltage lithium metal battery and preparation method thereof |
| CN115172868A (en) * | 2022-07-06 | 2022-10-11 | 北京理工大学 | Self-healing gel polymer electrolyte and preparation method and application thereof |
| CN115505115B (en) * | 2022-11-21 | 2023-03-14 | 北京理工大学深圳汽车研究院(电动车辆国家工程实验室深圳研究院) | Composition for preparing gel electrolyte, electrolyte and battery thereof |
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| CN110867613A (en) * | 2019-11-19 | 2020-03-06 | 凌帕新能源科技(上海)有限公司 | Silicon-carbon negative electrode lithium ion battery electrolyte and lithium battery |
| CN110911753A (en) * | 2019-12-13 | 2020-03-24 | 东莞东阳光科研发有限公司 | Non-aqueous electrolyte and lithium ion battery |
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