Copolymer electrolyte, its manufacturing method and solid-state lithium secondary battery

Abstract

A monomer composition, in particular for producing a polymer electrolyte precursor composition capable of forming a solid polymer electrolyte, comprises A) an alkylene oxide monomer; and B) a siloxane monomer. Also provided are a copolymerized polymer electrolyte precursor composition for producing a solid polymer electrolyte, a polymerization method for producing a solid copolymerized polymer electrolyte, a copolymer, a solid copolymerized polymer electrolyte, a solid lithium secondary battery, a method for producing a solid lithium secondary battery, use of the monomer composition or the copolymerized polymer electrolyte precursor composition in producing a solid polymer electrolyte of a lithium secondary battery, an electrochemical device, and a device.

Description

[Technical field]

[0001] The present invention relates to the technical field of lithium secondary batteries, and in particular to a copolymer electrolyte, a method for producing the copolymer electrolyte, and a solid-state lithium secondary battery.

[0002] Background technology Lithium secondary batteries are widely used in various portable electronic devices and electric vehicles. However, conventional lithium-ion secondary batteries based on liquid electrolytes and graphite anodes have a low theoretical specific capacity (372 mAhg -1 ), liquid organic electrolytes have potential safety issues due to leakage, volatilization, and combustion, and have limited energy density. On the other hand, solid-state lithium secondary batteries based on lithium metal anodes and solid electrolytes can effectively solve the above problems.

[0003] Among the reported solid electrolytes, solid polymer electrolytes (SPEs) have been widely studied due to their good interfacial contact with the active material, excellent geometric diversity, and high safety. Generally, SPEs are composed of a polymer and a lithium salt, where the polymer is Li + As a transport host, the lithium salt serves as the lithium source.PEO-based SPEs are still considered as promising polymer electrolytes due to their advantages such as stable complexation of ethylene oxide (EO) chains with Li ions, good flexibility, and electrochemical compatibility with lithium metal anodes.

[0004] However, it is well known that PEO-based polymer electrolytes usually have a trade-off between ionic conductivity and mechanical properties. In general, as the crystallinity of PEO-based electrolytes decreases, the ionic conductivity improves, but at the expense of mechanical strength, which makes it difficult to effectively suppress lithium dendrites. Although the mechanical strength can be improved by cross-linking reactions, the cross-linking reactions reduce the ionic conductivity, limiting its practical application. Therefore, it is a great challenge to develop PEO-based electrolytes that combine high ionic conductivity with good mechanical properties.

[0005] US Patent No. 6,933,078 discloses crosslinked polymer electrolytes comprising poly(ethylene glycol) methyl ether methacrylate (POEM) monomers crosslinked to a second monomer with a low Tg. Crosslinked polymer electrolytes such as POEM-X-PDMSD-LiN(CF3SO2)2 and POEM-X-PDMSM-PEGDME-LiN(CF3SO2)2 are disclosed. US Patent No. 6,933,078 does not disclose the preparation of POEM-X-PDMSM-PEGDME-LiN(CF3SO2)2, but mentions that "PDMSM can be easily grafted to POEM monomers, while PDMSD can be easily crosslinked with POEM monomers by free radical synthesis methods. (PDMSM crosslinked polymers can also be prepared by other synthesis methods.) POEM-g-PDMSM polymers are soluble electrolytes, have relatively low electrical conductivity, and have poor mechanical properties." Example 4 discloses the preparation of POEM-X-PDMSD-LiN(CF3SO2)2 by solution casting using POEM (14.8 ml), methacryloxypropyl-terminated polydimethylsiloxane (PDMSD) (4.0 ml), ethyl acetate (96 ml), LiN(CF3SO2)2 (1.8 g), and AIBN (0.072 g). The patent specification does not disclose the specific mechanical properties of the crosslinked polymer electrolyte prepared in the examples. The patent specification does not mention the interfacial stability between the polymer electrolyte and the lithium metal anode.

[0006] US 2003 / 0180624 discloses an interpenetrating network solid polymer electrolyte comprising at least one branched siloxane polymer having one or more poly(alkylene oxide) branches as side chains, at least one crosslinker, at least one monofunctional monomer compound for controlling crosslink density, at least one metal salt, and at least one radical initiator. In Examples 1 and 2, SPEs are prepared using 0.4-2.0 g of branched siloxane polymer, 0.4 g of poly(ethylene glycol-600) dimethacrylate (PEGDMA600), and 1.2-1.6 g of poly(ethylene glycol) ethyl ether methacrylate (PEGEEMA). During preparation, a porous polycarbonate membrane is used as the support for the IPN SPE. Both of the two IPN SPEs can be heated at room temperature for 10 -5 It exhibits high ionic conductivity exceeding 100 S / cm, and the ionic conductivity increases as the content of the branched siloxane polymer increases.

[0007] In addition, SPEs are usually produced by solution casting using a large amount of solvent, which is not only environmentally polluting but also time-consuming and costly, making it disadvantageous for mass production. Therefore, there is an urgent need to use a solvent-free, economical and efficient method for producing polymer electrolytes. In addition, there is a demand for providing solid-state lithium secondary batteries with excellent cycle and rate performance.

[0008] Summary of the Invention The object of the present invention is to provide a solid polymer electrolyte having high ionic conductivity, good mechanical strength, and excellent interfacial stability with a lithium metal negative electrode, and a solid lithium secondary battery using the solid polymer electrolyte and having excellent electrochemical performance such as cycle performance and rate performance. The solid polymer electrolyte can be produced by a solvent-free method.

[0009] Thus, the present invention provides a monomer composition, in particular for producing a polymer electrolyte precursor composition capable of forming a solid polymer electrolyte, wherein the monomer composition comprises: A) an alkylene oxide monomer; and B) Siloxane Monomer Comprises, consists essentially of, or consists of.

[0010] The present invention further provides a copolymeric polymer electrolyte precursor composition for producing a solid polymer electrolyte, wherein the polymer electrolyte precursor composition comprises: I) a monomer composition according to the present invention; II) a lithium salt; and optionally III) Free radical initiators for polymerization reactions Includes.

[0011] The present invention further provides the use of the monomer composition according to the present invention, or the use of the copolymeric polymer electrolyte precursor composition of the present invention, in the manufacture of a solid polymer electrolyte of a lithium secondary battery, in particular a lithium metal secondary battery, for improving performance, in particular mechanical properties, ionic conductivity and / or cycle performance of the electrolyte.

[0012] The present invention further provides a copolymer of an alkylene oxide monomer and a siloxane monomer according to the monomer composition of the present invention, which can be used as a polymer matrix (or host polymer) of a solid polymer electrolyte.

[0013] The present invention further comprises: - a copolymer of an alkylene oxide monomer and a siloxane monomer according to the monomer composition of the present invention; and - Lithium salts The present invention provides a solid copolymeric polymer electrolyte comprising:

[0014] The lithium salt is dispersed in the copolymer.

[0015] The present invention further relates to a method, in particular a polymerization method, for producing a solid copolymeric polyelectrolyte, comprising the steps of: a) mixing the copolymeric polyelectrolyte precursor composition of the present invention, comprising an alkylene oxide monomer, a siloxane monomer, a lithium salt, and an initiator, under a protective atmosphere until a homogeneous viscous liquid is formed; and b) A step of curing the liquid under UV irradiation or heat. The present invention provides a method comprising:

[0016] When the alkylene oxide monomer is a methoxypolyethylene glycol methacrylate (MPEG MA) monomer having a molecular weight of 950 to 2005, the method for producing a solid polymer electrolyte of the present invention can be carried out without using a solvent. The liquid preferably does not contain water or an organic solvent. Examples of the solvent include those conventionally used in the technical field, such as ethyl acetate, propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate, dimethyl sulfoxide, dimethoxyethane, N-methyl-2-pyrrolidone (NMP), and γ-butyrolactone (BL), but are not limited thereto.

[0017] The term "solvent-free" as used herein means that in the process for producing the solid polymer electrolyte of the present invention, no solvent is used in an amount that would allow the production of the solid polymer electrolyte by a solution casting process.

[0018] The chemical materials of the present process typically comprise a total of 0-10 wt.-%, for example 0-5 wt.-%, preferably 0-2 wt.-%, more preferably 0-1 wt.-%, even more preferably 0-0.5 wt.-%, particularly preferably 0-0.1 wt.-%, and most preferably no solvent, based on the total weight of the chemical materials used in the present process. Preferably, no additional organic solvent is used in the present process.

[0019] Importantly, the monomer compositions and / or copolymeric polymer electrolyte precursor compositions of the present invention enable the production of solid polymer electrolytes by solvent-free processes.

[0020] The present invention further provides a solid copolymeric polyelectrolyte produced by the method of the present invention.

[0021] The present invention further provides a solid-state lithium secondary battery comprising a positive electrode, a solid copolymeric polymer electrolyte according to the present invention, and a negative electrode, preferably a lithium metal negative electrode, which does not include a separator used in liquid lithium secondary batteries.

[0022] The present invention further provides a method for producing a solid-state lithium secondary battery, comprising the steps of: Assembling the positive electrode, the solid copolymeric polymer electrolyte according to the present invention, and a negative electrode, preferably a lithium metal negative electrode, to form a solid-state lithium secondary battery. The present invention provides a method comprising:

[0023] In the present invention, the term "solid polymer electrolyte" refers to an all-solid polymer electrolyte and / or a quasi-solid polymer electrolyte. The solid polymer electrolyte in the present invention is preferably an all-solid polymer electrolyte. When referring to the solid polymer electrolyte of the present invention, the term "copolymer electrolyte" is used interchangeably with "polymer electrolyte."

[0024] In the present invention, the "lithium secondary battery" includes lithium ion secondary batteries and lithium metal secondary batteries.

[0025] The present invention further provides an electrochemical device comprising a solid polymer electrolyte according to the present invention.

[0026] In some examples, the electrochemical device is a secondary battery, such as a lithium ion secondary battery, particularly a lithium metal secondary battery.

[0027] The present invention further provides devices comprising an electrochemical device according to the present invention, including, but not limited to, electric vehicles, household appliances, power tools, portable communication devices such as mobile phones, home appliances, and other products suitable for incorporating an electrochemical device or lithium secondary battery of the present invention as an energy source.

[0028] The siloxane monomer has a double bond that can be copolymerized with the alkylene oxide monomer to form a copolymer.

[0029] The weight ratio of the siloxane monomer to the alkylene oxide monomer is typically 1:0.4 to 1:80, for example 1:0.4 to 1:70, 1:0.4 to 1:60, 1:0.4 to 1:50, 1:0.6 to 1:80, 1:0.6 to 1:70, 1:0.6 to 1:60, 1:0.6 to 1:50, 1:0.8 to 1:80, 1:0.8 to 1:70, 1:0. 8~1:60, 1:0.8~1:55, 1:0.8~1:50, 1:2.4~1:80, 1:2.4~1:70, 1:2.4~1:60, 1:2.4~1:55, 1:2.4~1:50, 1:3.2~1:80, 1:3.2~1:70, 1:3.2~1:60, 1:3.2~1:55, 1:3.2~1:50, especially 1:0.8~1:52, is preferred. or 1:1.6~1:55, 1:3.2~1:55, 1:6.4~1:55, 10~60, 12~60, 15~60, 20~60, 25~60, 10~55, 12~55, 15~55, 20~55, 25~55, 1:12.8~1:55, 1:1.6~1:50, 1:3.2~1:50, 1:6.4~1:50, 1:12.8~1:50, 1 :3.2 to 1:52, particularly 1:1.6 to 1:52, more preferably 1:12.8 to 1:55, for example 1:16 to 1:55, 1:16 to 1:52, 1:20 to 1:52, 1:25 to 1:52, 1:16 to 1:50, 1:16 to 1:42, 1:16 to 1:32, 1:20 to 1:30, particularly 1:12.8 to 1:52, for example, about 1:25.6.

[0030] The present invention has surprisingly found that only a relatively small amount of siloxane monomer is required to maintain very good ionic conductivity of the solid polymer electrolyte while achieving much better mechanical strength of the solid polymer electrolyte compared to solid polymer electrolytes made only with alkylene oxide monomers. In this way, a good balance between mechanical strength and ionic conductivity is achieved.

[0031] Molar ratio of alkylene oxide monomer to lithium salt: AO / Li + is preferably (12-20):1, more preferably (14-18):1, and even more preferably about 16:1. + means a lithium ion (i.e., a charge carrier) provided by a lithium salt. AO represents an alkylene oxide repeat unit of an alkylene oxide monomer. For example, EO is represented by formula (I): -CH2CH2O- (I) where EO is a repeating unit of an EO-based monomer. When an EO-based monomer is used, the molar ratio AO / Li + is the molar ratio EO / Li + It is.

[0032] The curing or copolymerization reaction of the alkylene oxide monomer and the siloxane monomer can be carried out by UV irradiation or heat curing.

[0033] The copolymerization reaction is preferably initiated by UV irradiation. UV irradiation can be carried out with 310 nm to 380 nm UV in a protective atmosphere, for example at ambient temperature, for 30 to 240 minutes. In some embodiments, UV irradiation is carried out with 365 nm UV, and the time of UV irradiation is 120 minutes.

[0034] Copolymerization by UV irradiation can be carried out in a much shorter time than thermal initiation, resulting in significant time and cost savings. Importantly, as shown in the examples, the produced electrolytes provide superior electrochemical performance, e.g., superior ionic conductivity, compared to electrolytes produced by thermal initiation.

[0035] The thermal initiation can also be carried out under a protective atmosphere at 70° C. to 100° C. for 6 hours to 18 hours. In some embodiments, the thermal initiation is carried out at 80° C. and the heat cure time is 12 hours.

[0036] In some embodiments, the protective atmosphere is, for example, O2, H2O < 0.5 ppm under an argon atmosphere.

[0037] In some embodiments, a solventless polymerization method for producing a solid copolymeric polyelectrolyte includes: - freeze-drying the aqueous alkylene oxide monomer solution to remove water; - vigorously stirring the alkylene oxide monomer, the siloxane monomer, the lithium salt and the initiator under an argon atmosphere until a homogeneous viscous liquid is formed; - A process in which a viscous solution is cast and the liquid is cured under UV radiation or heat. Includes.

[0038] Siloxane Monomer The siloxane monomer is selected from organically modified siloxanes having ethylenically unsaturated radically polymerizable groups. The ethylenically unsaturated radically polymerizable groups are preferably selected from (meth)acryloxy functionalized siloxanes having ethylenically unsaturated radically polymerizable groups. The acryloxy functional groups are necessary for effective crosslinking.

[0039] To ensure effective crosslinking, the number of radically polymerizable groups in the siloxane monomer is typically 3 or more.

[0040] The siloxane monomer is preferably selected from (meth)acryloxy-functionalized siloxanes having from 4 to 40 silicon atoms, where 15% to 100% of the silicon atoms carry an ethylenically unsaturated radically polymerizable group.

[0041] In some embodiments, the siloxane monomer further comprises an ester group that is not radically polymerizable.

[0042] In some embodiments, the siloxane monomer has the formula (II): M 1 e M 3 f D 1g D 3 h (II) where: M 1 =[R 1 3SiO 1 / 2 ], M 3 =[R 1 2R 3 SiO 1 / 2 ], D 1 =[R 1 2SiO 2 / 2 ], D 3 =[R 1 R 3 SiO 2 / 2 ], e=0~2, f=0 to 2, preferably zero, e+f=2, g=0 to 38, preferably 10 to 26, h=0 to 20, for example, 1 to 20, or 2 to 20, or 3 to 20, preferably 4 to 15; the ratio of the sum (f+h) to the sum (g+h+2) is 0.15 to 1, preferably 0.2 to 0.5; The sum (g+h+2) is 4 to 40, preferably 10 to 30; R 1 represents identical or different aliphatic hydrocarbons having 1 to 10 carbon atoms or aromatic hydrocarbons having 6 to 12 carbon atoms, preferably a methyl and / or phenyl group, particularly preferably a methyl group, R 3 R represents identical or different hydrocarbons having 1 to 5 identical or different ester, preferably (meth)acryloxy functional groups, the hydrocarbons being linear, cyclic, branched and / or aromatic, preferably linear or branched, and the ester, preferably (meth)acryloxy functional groups, being selected from ethylenically unsaturated radically polymerizable esters, preferably (meth)acryloxy functional groups, and non-radical polymerizable ester groups. 3 The ester functional group is preferably a (meth)acryloxy functional group.

[0043] Preferably, in the siloxane monomer, the radically polymerizable groups are present in a numerical proportion of 80 to 90% relative to the total number of ester functional groups in the compound of formula (II).

[0044] The group R in the compound of formula (II) 3 The ethylenically unsaturated radically polymerizable ester functional groups are preferably selected from acrylic and / or methacrylic acid ester functional groups, more preferably acrylic acid ester functional groups.

[0045] The group R in the compound of formula (II) 3 The radically non-polymerizable ester groups are preferably monocarboxylic acid groups. The radically non-polymerizable ester groups are preferably selected from the acid groups of acetic acid, propionic acid, butyric acid, valeric acid and benzoic acid, more preferably acetic acid. More preferably, the monocarboxylic acid groups are present in a numerical proportion of 3% to 20%, preferably 5% to 15%, relative to the total number of ester functional groups of the compound of formula (II).

[0046] The organically modified silicones can be produced by the methods described in US Pat. No. 10,465,032 or US Pat. No. 4,978,726.

[0047] A preferred example of the above-mentioned siloxane monomer is TEGOMER® V-Si 7255, available from Evonik Industries AG.

[0048] TEGOMER® V-Si 7255 is a comb-type acryloxy-functional polysiloxane. Chemical name is Siloxane and Silicone, 3-[3-(acetyloxy)-2-hydroxypropoxy]propyl Me, di-Me, 3-[2-hydroxy-3-[(1-oxo-2-propen-1-yl)oxy]propoxy]propyl Me; CAS number: 125455-51-8.

[0049] Alkylene oxide monomers In the present invention, the term "alkylene oxide monomer" refers to an alkylene oxide monomer having one, two or more ethylenically unsaturated radical polymerizable groups. The alkylene oxide is preferably ethylene oxide (EO) or propylene oxide (PO). Therefore, the alkylene oxide monomer is preferably an EO monomer or a PO monomer.

[0050] The PO-based monomers can be selected from PO-based (meth)acrylates. The EO-based monomers can be selected from EO-based (meth)acrylates, in particular polyethylene glycol (PEG) (meth)acrylates, such as the following monomers: Methoxypolyethyleneglycol methacrylate (MPEG MA), Polyethylene glycol dimethacrylate (PEGDMA), Polyethylene glycol methyl ether acrylate (PEGMEA) and Polyethylene glycol diacrylate (PEGDA).

[0051] Methoxypolyethyleneglycol methacrylate (MPEG MA) monomers have the following general formula (III): [ka] Here, the molecular weight of the MPEG MA monomer is 200 to 20,000, preferably 750 to 5,005, and more preferably 950 to 2,005.

[0052] The aqueous MPEG MA solution may be VISIOMER® MPEG 750 MA W, VISIOMER® MPEG 1005 MA W, VISIOMER® MPEG 2005 MA W, VISIOMER® MPEG 5005 MA W, all of which are commercially available from Evonik Industries AG. Preferably, the aqueous MPEG MA solution is VISIOMER® MPEG 1005 MA W.

[0053] VISIOMER® MPEG 1005 MA W stands for methoxypolyethylene glycol 1000-methacrylate, 50% by weight in water. It is a highly polar monomer (50% by weight in water) with excellent water solubility. This monomer can be represented by formula (III) with a molecular weight of 1005.

[0054] Polyethylene glycol dimethacrylate (PEGDMA) monomers have the following general formula (IV): [ka] Here, the molecular weight of the PEGDMA monomer is 200 to 20,000, preferably 550 to 6,000, and more preferably 750 to 2,000.

[0055] Polyethylene glycol methyl ether acrylate (PEGMEA) monomers have the following general formula (V): [ka] Here, the molecular weight of the PEGMEA monomer is 200 to 20,000, preferably 300 to 5,000, and more preferably 400 to 2,000.

[0056] Polyethylene glycol diacrylate (PEGDA) monomers have the following general formula (VI): [ka] Here, the molecular weight of the PEGDA monomer is 200 to 20,000, preferably 400 to 5,000, and more preferably 600 to 2,000.

[0057] The alkylene oxide monomer may be a solid. In some embodiments, the alkylene oxide monomer is obtained by freeze-drying the aqueous solution thereof, for example, at a vacuum of <20 Pa and a cold trap temperature of <-40°C for at least 72 hours. In one embodiment, the freeze-drying time of the aqueous solution of the alkylene oxide monomer is 80 hours.

[0058] Lithium salt The lithium salt is a substance that dissolves in a non-aqueous electrolyte and dissociates lithium ions.

[0059] The lithium salt may be any conventionally used in the art, but may be thermally stable (e.g., at 80° C.) during in situ polymerization, and non-limiting examples include lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium difluorooxalatoborate (LiODFB), LiAsF, LiClO, LiN(CFSO), LiBF, LiSbF, and LiCl, LiBr, LiI, LiB 10 Cl 10 , LiCF3SO3, LiCF3CO2, LiAlCl4, CH3SO3Li, CF3SO3Li, (CF3SO2)2NLi, lithium chloroborane, lithium lower aliphatic carboxylate, lithium tetraphenylborate and imide. The lithium salt is preferably selected from LiTFSI, LiFSI and LiClO4. These materials may be used alone or in any combination.

[0060] Free Radical Initiators The free radical initiator of the polymerization reaction may be any of those conventionally used in the art for the thermal or photopolymerization of reactive monomers.

[0061] Examples of free radical initiators or polymerization initiators include azo compounds such as 2,2-azobis(2-cyanobutane), 2,2-azobis(methylbutyronitrile), 2,2'-azoisobutyronitrile (AIBN), azobisdimethylvaleronitrile (AMVN), etc., peroxy compounds such as benzoyl peroxide, acetyl peroxide, dilauryl peroxide, di-tert-butyl peroxide, cumyl peroxide, hydrogen peroxide, etc., and hydroperoxides.Preferably, AIBN, 2,2'-azobis(2,4-dimethylvaleronitrile) (V65), di-(4-tert-butylcyclohexyl)peroxydicarbonate (DBC), etc. can also be used.

[0062] Preferably, the free radical thermal initiator may be selected from azobisisobutyronitrile (AIBN), azobisisoheptanenitrile (ABVN), benzoyl peroxide (BPO), lauroyl peroxide (LPO), etc. More preferably, the free radical initiator is benzoyl peroxide (BPO) or azobisisobutyronitrile (AIBN).

[0063] Free radical photoinitiators generate free radicals when exposed to UV light, which then set up polymerization. Examples of photoinitiators include benzoyl compounds such as 2,2-dimethoxy-1,2-diphenylethan-1-one (DMPA), benzil dimethyl ketal, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), 2-hydroxy-2-methylpropiophenone (HMPP), 1-hydroxycyclohexyl phenyl ketone (HCPK), and the like.

[0064] Preferably, the free radical photoinitiator can be selected from 2,2-dimethoxy-1,2-diphenylethan-1-one (DMPA), benzil dimethyl ketal, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), etc. More preferably, the free radical photoinitiator is 2,2-dimethoxy-1,2-diphenylethan-1-one (DMPA).

[0065] The amount of free radical initiator is conventional, preferably between 0.1 and 3% by weight, more preferably about 0.5% by weight, based on the total weight of the monomers of the copolymer.

[0066] In some embodiments, the amount of the photopolymerization initiator or thermal polymerization initiator may be 0.2% to 2% by weight, preferably about 0.5% by weight, based on the total weight of the alkylene oxide monomer and the siloxane monomer. The photopolymerization initiator or thermal polymerization initiator generates free radicals under UV irradiation or heating to initiate polymerization.

[0067] In some embodiments, the polymerization initiator decomposes at a certain temperature between 40 and 80° C. to form radicals that can react with monomers to form polyelectrolytes via free radical polymerization. In general, free radical polymerization is carried out by sequential reactions including initiation, which involves the formation of a transient molecule with a highly reactive or active site, propagation, which involves the reformation of the active site at the chain end by the addition of monomer to the active chain end, chain transfer, which involves the transfer of the active site to another molecule, and termination, which involves the destruction of the active chain center.

[0068] Preferably, the solid-state lithium secondary battery is a coin-type battery or a pouch-type battery.

[0069] The electrochemical device includes any type of device that causes an electrochemical reaction. Examples of the electrochemical device include any type of primary battery, secondary battery, fuel cell, solar cell, capacitor, etc., and preferably a secondary battery.

[0070] In general, a secondary battery is produced by sealing an electrolyte in an electrode assembly consisting of a positive electrode and a negative electrode facing each other with a separator sandwiched therebetween (or without a separator in the case of SPE).

[0071] The positive electrode is prepared, for example, by applying a mixture of a positive electrode active material, a conductive material, and a binder to a positive electrode current collector, followed by drying and pressing. If necessary, a filler can be further added to the mixture.

[0072] The positive electrode current collector is generally made to a thickness of 3 to 500 μm. There is no particular limitation on the material of the positive electrode current collector as long as it has high conductivity without causing chemical changes in the battery produced. Examples of the material of the positive electrode current collector include stainless steel, aluminum, nickel, titanium, sintered carbon, and aluminum or stainless steel that has been surface-treated with carbon, nickel, titanium, or silver. The current collector can be made to have fine irregularities on its surface in order to enhance adhesion to the positive electrode active material. Furthermore, the current collector can take various forms such as a film, sheet, foil, net, porous structure, foam, and nonwoven fabric.

[0073] Examples of positive electrode active materials that can be used in the present invention include layered compounds such as lithium cobalt oxide (LiCoO2) and lithium nickel oxide (LiNiO2), or LiNi x Co y Mn 1-x-y (NCM); a compound of formula Li 1+x Mn 2-x O4 (0≦x≦0.33), lithium manganese oxides such as LiMnO3, LiMn2O3 and compounds of LiMnO2; lithium copper oxide (Li2CuO2); vanadium oxides such as LiV3O8, V2O5 and Cu2V2O7; 1-x M x Lithium nickel oxide with Ni site of O2 (M=Co, Mn, Al, Cu, Fe, Mg, B or Ga and 0.01≦x≦0.3); formula LiMn 2-x M xLiMn2O4 in which part of the Li is replaced by an alkaline earth metal ion; disulfide compounds; and Fe2(MoO4)3, LiFe3O4, etc., but are not limited to these. In some embodiments, the positive electrode active material is LiFePO4, LiCoO2, LiNi 0.8 Mn 0.1 Co 0.1 O2, LiNi 0.6 Mn 0.2 Co 0.2 O2, LiNi 0.85 Co 0.05 Al 0.1 O2, all of which are common cathodes available commercially.

[0074] In some embodiments, a cathode slurry is obtained by blending the cathode active material, super-p, binder, and lithium perchlorate (LiClO4) in a solvent, and then the slurry is directly loaded onto an aluminum foil by blade casting and dried under vacuum to remove the solvent. In some embodiments, the weight ratio of the cathode active material, super-p, binder, and LiClO4 is (67%-89%):(5%-20%):(5%-10%):(1%-3%).

[0075] Preferably, the weight ratio of the positive electrode active material, super-p, binder, and LiClO4 is 78.94%:9.87%:9.87%:1.32%.

[0076] Preferably, the solvent used in preparing the positive electrode slurry is acetonitrile or N-methylpyrrolidone. Typically, when the binder is PEO, acetonitrile is used. When the binder is PVDF, N-methylpyrrolidone is used.

[0077] The drying temperature of the positive electrode slurry is preferably 60° C. to 120° C. The drying time of the positive electrode slurry is preferably 10 to 24 hours, and more preferably 12 hours.

[0078] The conductive material is typically added in an amount of 1 to 50% by weight based on the total weight of the mixture containing the positive electrode active material. There are no particular limitations on the conductive material as long as it has appropriate conductivity without causing chemical changes in the produced battery. Examples of the conductive material include graphite such as natural graphite and artificial graphite; carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers such as carbon fiber and metal fiber; metal powders such as carbon fluoride powder, aluminum powder, and nickel powder; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and conductive materials including polyphenylene derivatives.

[0079] The binder is a component that assists in binding the active material to the conductive material and to the current collector. The binder is typically added in an amount of 1 to 50% by weight based on the total weight of the mixture including the positive electrode active material. Examples of binders include polyvinylidene fluoride, poly(ethylene oxide) (PEO), polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butadiene rubber, fluororubber, and various copolymers.

[0080] In some embodiments, the polymer binder is poly(ethylene oxide) (PEO) or poly(vinylidene fluoride) (PVDF).

[0081] The filler is an optional component used to suppress the expansion of the cathode. There is no particular limitation on the filler as long as it is a fibrous material that does not cause a chemical change in the fabricated battery. Examples of the filler include olefin polymers such as polyethylene and polypropylene; and fibrous materials such as glass fiber and carbon fiber. The negative electrode is fabricated by applying the negative electrode active material to the negative electrode current collector and then drying it. If necessary, other components such as those described above may be further included.

[0082] The negative electrode current collector is generally prepared to a thickness of 3 to 500 μm. There is no particular limitation on the material of the negative electrode current collector as long as it has appropriate conductivity without causing chemical changes in the prepared battery. Examples of the material of the negative electrode current collector include copper, stainless steel, aluminum, nickel, titanium, sintered carbon, copper or stainless steel surface-treated with carbon, nickel, titanium or silver, and aluminum-cadmium alloy. As with the positive electrode current collector, the negative electrode current collector can also be processed so that fine irregularities are formed on its surface in order to increase the adhesive strength with the negative electrode active material. Furthermore, the negative electrode current collector can be used in various forms such as a film, sheet, foil, net, porous structure, foam and nonwoven fabric.

[0083] Examples of the negative electrode active material that can be used in the present invention include carbon such as non-graphitizable carbon and graphitic carbon; Li x Fe2O3(0≦x≦1), Li x WO2(0≦x≦1) and Sn x Me 1-x Me' y O zMetal composite oxides such as (Me: Mn, Fe, Pb or Ge; Me': Al, B, P, Si, Group 1, 2 and 3 elements of the Periodic Table of Elements, or halogens; 0≦x≦1; 1≦y≦3; and 1≦z≦8); lithium metal; lithium alloys; silicon-based alloys; tin-based alloys; metal oxides such as SnO, SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3, Bi2O4 and Bi2O5; conductive polymers such as polyacetylene; and Li-Co-Ni-based materials. In some examples of the present invention, lithium metal is used as the negative electrode.

[0084] The secondary battery according to the present invention may be, for example, a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, a lithium ion polymer secondary battery, etc. The secondary battery may be fabricated in various forms. For example, the electrode assembly may be configured in a jelly roll structure, a laminated structure, a laminated / folded structure, etc. The battery may be configured by placing the electrode assembly in a battery case of a cylindrical can, a square can, or a laminated sheet including a metal layer and a resin layer. Such battery configurations are widely known in the art.

[0085] Thus, the present invention provides a novel monomer composition and polymer electrolyte precursor composition capable of forming a solid polymer electrolyte having excellent performance such as high ionic conductivity, good mechanical strength, and excellent interfacial stability with a lithium metal negative electrode, and a solid lithium secondary battery using the solid polymer electrolyte and having excellent electrochemical performance such as cycle performance and rate performance.

[0086] The copolymer electrolyte provided by the present invention has high ionic conductivity, good mechanical strength, excellent dendrite suppression ability and thermal stability.

[0087] The present invention also provides a solvent-free polymerization method for preparing a copolymerized polyelectrolyte, which avoids solvent contamination, has high production efficiency, and can be carried out at room temperature, which is advantageous for industrial mass production.

[0088] The solid-state lithium secondary battery provided by the present invention exhibits excellent cycle performance and rate performance.

[0089] Other advantages of the invention will be apparent to those skilled in the art upon reading the specification. [Brief description of the drawings]

[0090] [Figure 1] FIG. 2 is a diagram showing a stress-strain curve of the electrolyte obtained in Example 2. [Diagram 2] FIG. 13 is a diagram showing the stress-strain curve of the electrolyte obtained in Example 5. [Diagram 3] FIG. 1 shows micro-Fourier transform infrared spectroscopy (Micro-FTIR) spectra of a reactive monomer and the copolymerized polymer electrolyte obtained in Example 6. [Figure 4] FIG. 1 shows a scanning electron microscopy (SEM) image and corresponding elemental distribution spectroscopy (EDS) mapping of the electrolyte obtained in Example 6. [Diagram 5] FIG. 1 is a diagram showing a thermogravimetric analysis (TGA) curve of the electrolyte obtained in Example 6. [Figure 6] FIG. 1 shows a differential scanning calorimetry (DSC) curve of the electrolyte obtained in Example 6. [Figure 7] FIG. 13 is a diagram showing the stress-strain curve of the electrolyte obtained in Example 6. [Figure 8] FIG. 13 shows galvanostatic cycling at 60° C. and a current density of 0.1 mA cm−2 for the Li / electrolyte / Li symmetric cell of Example 6. [Figure 9] FIG. 13 is a diagram showing the stress-strain curve of the electrolyte obtained in Example 8. [Figure 10] FIG. 13 is a graph showing the rate capacity at 60° C. and each C rate of the all-solid-state lithium secondary battery using the electrolyte of Example 6. [Figure 11] FIG. 13 is a diagram showing the charge / discharge profile at 60° C. and at each rate of the all-solid-state lithium secondary battery using the electrolyte of Example 6. [Figure 12]FIG. 13 is a graph showing the cycle performance at 60° C. and 0.1 C of an all-solid-state lithium secondary battery using the electrolyte of Example 6. [Figure 13] FIG. 13 is a graph showing the cycle performance at 60° C. and 1C of an all-solid-state lithium secondary battery using the electrolyte of Example 6. [Figure 14] FIG. 2 is a graph showing the stress-strain curve of the electrolyte obtained in Comparative Example 1. [Figure 15] FIG. 2 shows the constant current cycle at 60° C. and a current density of 0.1 mA cm −2 for the Li / electrolyte / Li symmetric cell of Comparative Example 1. [Figure 16] FIG. 13 is a graph showing the stress-strain curve of the electrolyte obtained in Comparative Example 2. [Figure 17] FIG. 1 is a graph showing the rate capacity at 60° C. and each C rate of an all-solid-state lithium secondary battery using the electrolyte of Comparative Example 1. [Figure 18] FIG. 1 is a graph showing the cycle performance at 60° C. and 0.1 C of an all-solid-state lithium secondary battery using the electrolyte of Comparative Example 1.

[0091] Detailed Description of the Invention The present invention will now be described in more detail with reference to the following examples, the scope of which should not be limited to the embodiments of the examples.

[0092] Analytical procedures The ionic conductivity of the resulting electrolyte was measured by electrochemical impedance spectroscopy (EIS) at an amplitude of 10 mV in the frequency range of 10 MHz–10 Hz using a Solartron 1470E multichannel potentiostat electrochemical workstation (Solartron Analytical, UK). The ionic conductivity was calculated by the formula σ = L / (S·R), where L is the thickness of the electrolyte, R is the resistance of the bulk electrolyte, and S is the effective contact area between the SS electrode and the electrolyte.

[0093] The chemical structures of the obtained electrolytes were characterized by micro-Fourier transform infrared spectroscopy (Micro-FTIR, Cary660+620, Agilent, USA).

[0094] The morphology and elemental distribution spectroscopy (EDS) mapping of the obtained electrolytes were investigated by field emission scanning electron microscope (FE-SEM, S4800, Hitachi, Japan).

[0095] The thermal behavior of the obtained electrolyte was examined by differential scanning calorimetry (DSC, DSC214, NETZSCH, Germany) from -60°C to 80°C for 10°C min -1 The temperature was increased from 30°C to 600°C in 10°C min under nitrogen atmosphere by thermogravimetric analysis (TGA, Diamond TG / DTA, PerkinElmer, USA). -1 The measurement was performed at a heating rate of 100°C.

[0096] The mechanical strength of the obtained electrolyte was tested by stress-strain measurement using an Electronic Universal Testing Machine (CMT-1104, Zhuhai SUST Electrical Equipment Co. Ltd., China).

[0097] Charge-discharge cycling was performed on a LAND charge-discharge device (LAND CT2001A, Wuhan Rambo Testing Equipment Co., Ltd., China).

[0098] In the examples, purified VISIOMER® MPEG 1005 MA W was obtained as follows: VISIOMER® MPEG 1005 MA W was put into a freezer to freeze, and then the frozen sample was freeze-dried in a vacuum freeze dryer SCIENTZ-10N (Ningbo Scientz Biotechnology Co., Ltd., China) at a vacuum degree of <20 Pa and a cold trap temperature of <-40°C for 80 hours to remove water.

[0099] Example 1 Purified solid VISIOMER® MPEG 1005 MA W monomer (1.4680 g), TEGOMER® V-Si 7255 (1.8259 g), LiTFSI (0.5320 g), 1 wt. % DMPA (0.0238 g, based on the weight of TEGOMER® V-Si 7255 and VISIOMER® MPEG 1005 MA W monomer) were vigorously stirred under an argon atmosphere until a homogeneous viscous liquid was formed, and the molar ratio EO / Li + The weight ratio of TEGOMER® V-Si 7255 to purified VISIOMER® MPEG 1005 MA W was 1:0.804, with the weight ratio of TEGOMER® V-Si 7255 to purified VISIOMER® MPEG 1005 MA W being 18:1. The precursor solution was then cast onto a Teflon plate and exposed to a 365 nm UV beam at ambient temperature for 100 minutes. Finally, a solvent-free, self-supporting copolymeric polyelectrolyte was obtained. The copolymeric polyelectrolyte of Example 1 had a molecular weight of 1.22×10 at 30° C. -6 Scm -1 , 7.58 x 10 at 60 °C -6 Scm -1 The ionic conductivity was .

[0100] Example 2 Purified VISIOMER® MPEG 1005 MA W monomer (1.4680 g), TEGOMER® V-Si 7255 (0.9130 g), LiTFSI (0.5320 g), 1 wt. % DMPA (0.0238 g, based on the weight of TEGOMER® V-Si 7255 and VISIOMER® MPEG 1005 MA W monomer) were vigorously stirred under an argon atmosphere until a homogeneous viscous liquid was formed, with the molar ratio EO / Li + The weight ratio of TEGOMER® V-Si 7255 to purified VISIOMER® MPEG 1005 MA W was 1:1.608, with a weight ratio of 18:1 and 1:1.608. The precursor solution was then cast onto a Teflon plate and exposed to a 365 nm UV beam at ambient temperature for 100 minutes. Finally, a solvent-free, self-supporting copolymeric polyelectrolyte was obtained. The copolymeric polyelectrolyte of Example 2 had a molecular weight of 2.02×10 at 30° C. -5 Scm-1 , 9.82 x 10 at 60 °C -5 Scm -1 The ionic conductivity was .

[0101] The mechanical strength of the electrolyte obtained in Example 2 was tested by stress-strain measurement. As shown in FIG. 1, the electrolyte obtained in Example 2 was brittle, with a breaking elongation of only 1.75%. The tensile strength of the electrolyte obtained in Example 2 was 22.57 KPa, and the Young's modulus was 1156.64 KPa. The electrolyte obtained in Example 2 had a much higher mechanical strength than the electrolytes in Comparative Examples 1 and 2 described below.

[0102] Example 3 Purified VISIOMER® MPEG 1005 MA W monomer (1.4680 g), TEGOMER® V-Si 7255 (0.4565 g), LiTFSI (0.5320 g), 0.5 wt. % DMPA (0.0096 g, based on the weight of TEGOMER® V-Si 7255 and VISIOMER® MPEG 1005 MA W monomer) were vigorously stirred under an argon atmosphere until a homogeneous viscous liquid was formed, with the molar ratio EO / Li + The weight ratio of TEGOMER® V-Si 7255 to purified VISIOMER® MPEG 1005 MA W was 1:3.216, with a weight ratio of 18:1 and 1:3.216. The precursor solution was then cast onto a Teflon plate and exposed to a 365 nm UV beam at ambient temperature for 100 minutes. Finally, a solvent-free, self-supporting copolymeric polyelectrolyte was obtained. The copolymeric polyelectrolyte of Example 3 had a molecular weight of 2.18×10 at 60° C. -4 Scm -1 The ionic conductivity was .

[0103] Example 4 Purified VISIOMER® MPEG 1005 MA W monomer (1.4680 g), TEGOMER® V-Si 7255 (0.1141 g), LiTFSI (0.5320 g), 0.5 wt. % DMPA (0.0079 g, based on the weight of TEGOMER® V-Si 7255 and VISIOMER® MPEG 1005 MA W monomer) were vigorously stirred under an argon atmosphere until a homogeneous viscous liquid was formed, with the molar ratio EO / Li + The weight ratio of TEGOMER® V-Si 7255 to purified VISIOMER® MPEG 1005 MA W was 1:12.864, with a weight ratio of 18:1 and 1:12.864 for TEGOMER® V-Si 7255 and purified VISIOMER® MPEG 1005 MA W. The precursor solution was then cast onto a Teflon plate and exposed to a 365 nm UV beam at ambient temperature for 100 minutes. Finally, a solvent-free, self-supporting copolymeric polyelectrolyte was obtained. The copolymeric polyelectrolyte of Example 3 had a molecular weight of 5.85×10 at 30° C. -5 Scm -1 , 2.38 x 10 at 60 °C -4 Scm -1 The ionic conductivity was .

[0104] Example 5 Purified VISIOMER® MPEG 1005 MA W monomer (1.4680 g), TEGOMER® V-Si 7255 (0.0571 g), LiTFSI (0.5320 g), 0.5 wt. % DMPA (0.0076 g, based on the weight of TEGOMER® V-Si 7255 and VISIOMER® MPEG 1005 MA W monomer) were vigorously stirred under an argon atmosphere until a homogeneous viscous liquid was formed, with the molar ratio EO / Li + The weight ratio of TEGOMER® V-Si 7255 to purified VISIOMER® MPEG 1005 MA W was 1:25.728, with a weight ratio of 18:1 and 1:25.728 of TEGOMER® V-Si 7255 to purified VISIOMER® MPEG 1005 MA W. The precursor solution was then cast onto a Teflon plate and exposed to a 365 nm UV beam at ambient temperature for 100 minutes. Finally, a solvent-free, self-supporting copolymeric polyelectrolyte was obtained. The copolymeric polyelectrolyte of Example 5 had a molecular weight of 7.10×10 at 30° C. -5 Scm-1 , 2.92 x 10 at 60 °C -4 Scm -1 The ionic conductivity was .

[0105] The mechanical strength of the electrolyte obtained in Example 5 was tested by stress-strain measurement. As shown in Figure 2, the tensile strength of the electrolyte obtained in Example 5 was 20.05 KPa and the Young's modulus was 27.42 KPa. The electrolyte obtained in Example 5 had a much higher mechanical strength than the electrolytes in Comparative Examples 1 and 2 described below.

[0106] Example 6 Purified VISIOMER® MPEG 1005 MA W monomer (1.4680 g), TEGOMER® V-Si 7255 (0.0571 g), LiTFSI (0.5985 g), 0.5 wt. % DMPA (0.0076 g, based on the weight of TEGOMER® V-Si 7255 and VISIOMER® MPEG 1005 MA W monomer) were vigorously stirred under an argon atmosphere until a homogeneous viscous liquid was formed, and the weight ratio of EO / Li + The molar ratio of TEGOMER® V-Si 7255 to purified VISIOMER® MPEG 1005 MA W was 1:25.728, with a molar ratio of 16:1 and 1:25.728 of TEGOMER® V-Si 7255 to purified VISIOMER® MPEG 1005 MA W. The precursor solution was then cast onto a Teflon plate and exposed to a 365 nm UV beam at ambient temperature for 100 minutes. Finally, a solvent-free, self-supporting copolymeric polyelectrolyte was obtained. The copolymeric polyelectrolyte of Example 6 was dissolved in a 1×10 -4 Scm -1 , 3.86 x 10 at 60 °C -4 Scm -1 The ionic conductivity was .

[0107] The structure of the electrolyte obtained in Example 6 was characterized by Micro-FTIR and FE-SEM. As shown in Figures 3 and 4, the peaks at 1633 cm of the C=C double bonds in the purified VISIOMER MPEG 1005 MA W monomer and TEGOMER V-Si 7255 were -1The reactive group located at has disappeared in the electrolyte obtained in Example 6, and C, Si and S are uniformly distributed in the electrolyte obtained in Example 6, which proves that the copolymer electrolyte of Example 6 has been successfully prepared.

[0108] The thermal behavior of the electrolyte obtained in Example 6 was investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The TGA results are shown in Figure 5. The electrolyte remained stable up to 330.49°C with a weight loss of 8%. As shown in Figure 6, the glass transition temperature (T g ) was −49.6°C, and no endothermic peak was observed with increasing temperature. This result indicates that the electrolyte is completely amorphous, which is favorable for ionic conduction.

[0109] The mechanical strength of the electrolyte obtained in Example 6 was tested by stress-strain measurement. As shown in Fig. 7, the tensile strength of the electrolyte obtained in Example 6 was 17.28 KPa and the Young's modulus was 24.43 KPa. The electrolyte according to the present invention had a much higher mechanical strength than the electrolytes in Comparative Examples 1 and 2 described below.

[0110] The interface stability between the electrolyte obtained in Example 6 and lithium metal was tested. The Li / electrolyte / Li symmetric cell was found to have a current density of 0.1 mAcm at 60°C. -2 The battery could be stably cycled for over 1,800 hours at 10000K (Fig. 8). This result indicates that the electrolyte has excellent stability with lithium metal and good mechanical properties that can effectively suppress lithium dendrites.

[0111] Example 7 Purified VISIOMER® MPEG 1005 MA W monomer (1.4680 g), TEGOMER® V-Si 7255 (0.0571 g), LiTFSI (0.6840 g), 0.5 wt. % DMPA (0.0076 g, based on the weight of TEGOMER® V-Si 7255 and VISIOMER® MPEG 1005 MA W monomer) were vigorously stirred under an argon atmosphere until a homogeneous viscous liquid was formed, with the molar ratio EO / Li + The weight ratio of TEGOMER® V-Si 7255 to purified VISIOMER® MPEG 1005 MA W was 1:25.728, with a weight ratio of 14:1 and 1:25.728 of TEGOMER® V-Si 7255 to purified VISIOMER® MPEG 1005 MA W. The precursor solution was then cast onto a Teflon plate and exposed to a 365 nm UV beam at ambient temperature for 100 minutes. Finally, a solvent-free, self-supporting copolymeric polyelectrolyte was obtained. The copolymeric polyelectrolyte of Example 7 had a molecular weight of 7.15×10 at 30° C. -5 Scm -1 , 3.12 x 10 at 60 °C -4 Scm -1 The ionic conductivity was .

[0112] Example 8 Purified VISIOMER® MPEG 1005 MA W monomer (1.4680 g), TEGOMER® V-Si 7255 (0.0285 g), LiTFSI (0.5985 g), 0.5 wt. % DMPA (0.0075 g, based on the weight of TEGOMER® V-Si 7255 and VISIOMER® MPEG 1005 MA W monomer) were vigorously stirred under an argon atmosphere until a homogeneous viscous liquid was formed, with the molar ratio EO / Li + The weight ratio of TEGOMER® V-Si 7255 to purified VISIOMER® MPEG 1005 MA W was 1:51.456, with a weight ratio of 16:1 and 1:51.456 of TEGOMER® V-Si 7255 to purified VISIOMER® MPEG 1005 MA W. The precursor solution was then cast onto a Teflon plate and exposed to a 365 nm UV beam at ambient temperature for 100 minutes. Finally, a solvent-free, self-supporting copolymeric polyelectrolyte was obtained. The copolymeric polyelectrolyte of Example 8 had a molecular weight of 1.15×10 at 30° C. -4 Scm-1 , 4.88 x 10 at 60 °C -4 Scm -1 The ionic conductivity was .

[0113] The mechanical strength of the electrolyte obtained in Example 8 was tested by stress-strain measurement. As shown in Fig. 9, the tensile strength of the electrolyte obtained in Example 8 was 13.22 KPa and the Young's modulus was 14.85 KPa. The electrolyte obtained in Example 8 had a higher mechanical strength than the electrolytes in Comparative Examples 1 and 2 described below.

[0114] Example 9 Purified VISIOMER® MPEG 1005 MA W monomer (1.4680 g), TEGOMER® V-Si 7255 (0.0571 g), LiTFSI (0.5985 g), 0.5 wt. % BPO (0.0076 g, based on the weight of TEGOMER® V-Si 7255 and VISIOMER® MPEG 1005 MA W monomer) were vigorously stirred under an argon atmosphere until a homogeneous viscous liquid was formed, with the molar ratio EO / Li + The weight ratio of TEGOMER® V-Si 7255 to purified VISIOMER® MPEG 1005 MA W was 1:25.728. The precursor solution was then cast onto a Teflon plate and placed in an oven at 80° C. for 12 hours. The copolymer electrolyte of Example 9 had a molecular weight of 5.56×10 at 30° C. -5 Scm -1 , 3.11 x 10 at 60 °C -4 Scm -1 The ionic conductivity was .

[0115] Example 10 An all-solid-state lithium secondary battery consisting of a positive electrode, the electrolyte obtained in Example 6, and a lithium metal negative electrode was further assembled under an argon atmosphere (O2, H2O<0.5ppm). A positive electrode slurry was obtained by blending LiFePO4 (0.4g) / carbon black Super-P (0.05g) / PEO (0.05g) / LiClO4 (0.0067g) in acetonitrile with a weight ratio of 78.94%:9.87%:9.87%:1.32%, and then the slurry was directly loaded onto an aluminum foil by blade casting and dried under vacuum at 100°C for 12 hours to remove the solvent.

[0116] Figure 10 shows the rate performance of the all-solid-state lithium secondary battery at 60°C. As shown in Figure 10, the maximum discharge specific capacity of the battery at 0.1C, 0.2C, 0.5C, 1C, 2C and 3C was 169.2mAhg, respectively. -1 , 166.8mAhg -1 , 160.5mAhg -1 , 140.3mAhg -1 , 81.9mAhg -1 , 46.3mAhg -1 This demonstrates the excellent rate capability of the all-solid-state lithium cell.

[0117] FIG. 11 shows the charge / discharge profile of the all-solid-state lithium secondary battery at each C rate. The voltage polarization plateau is the peak of the Fe in the LiFePO4 positive electrode. 2+ / Fe 3+ The polarization voltage increases as the C rate increases, but this is mainly due to the electrochemical polarization and the Li + This is due to concentration polarization.

[0118] The cycle performance of the all-solid-state lithium secondary battery was evaluated at 60°C and 0.1C. As shown in Figure 12, the all-solid-state lithium secondary battery had a capacity of 158.7mAhg even after 200 cycles. -1The all-solid-state lithium secondary battery still exhibited a discharge capacity of 130.3 mAhg / s after 500 cycles, with a capacity retention rate of 97.6%, demonstrating the excellent cycle performance of the all-solid-state lithium cell. Furthermore, the cycle performance of this all-solid-state lithium secondary battery was evaluated at a higher C rate at 60°C. As shown in FIG. 13, after 11 cycles at 0.1C, 5 cycles at 0.2C, and 5 cycles at 0.5C, when the C rate was increased to 1C, the all-solid-state lithium secondary battery still exhibited a discharge capacity of 130.3 mAhg / s after 500 cycles. -1 The discharge capacity was still able to be exhibited, and the capacity retention rate was 85.6%.

[0119] Comparative Example 1 Purified VISIOMER® MPEG 1005 MA W monomer (1.4680 g), LiTFSI (0.5320 g), 0.5 wt. % DMPA (0.0073 g, relative to the weight of VISIOMER® MPEG 1005 MA W monomer) were vigorously stirred under an argon atmosphere until a homogeneous viscous liquid was formed, with the molar ratio EO / Li + The ratio of the precursor solution to the total volume of the electrolyte was 18:1. The precursor solution was cast onto a Teflon plate and exposed to a 365 nm UV beam at ambient temperature for 120 minutes. The electrolyte obtained in Comparative Example 1 had a molecular weight of 1.51×10 -4 Scm -1 , 7.87 x 10 at 60 °C -4 Scm -1 The ionic conductivity was .

[0120] The mechanical strength of the electrolyte obtained in Comparative Example 1 was tested by stress-strain measurement. As shown in Figure 14, the tensile strength of the electrolyte obtained in Comparative Example 1 was 6.96 KPa, and the Young's modulus was only 6.99 KPa.

[0121] When the interface stability between the electrolyte obtained in Comparative Example 1 and lithium metal was tested, as shown in FIG. 15, the symmetrical Li / electrolyte / Li battery showed fluctuations after 800 hours and a short circuit occurred after 900 hours of cycling.

[0122] Comparative Example 2 Purified VISIOMER® MPEG 1005 MA W monomer (1.4680 g), LiTFSI (0.5985 g), 0.5 wt. % DMPA (0.0073 g, relative to the weight of VISIOMER® MPEG 1005 MA W monomer) were vigorously stirred under an argon atmosphere until a homogeneous viscous liquid was formed, with the molar ratio EO / Li + The ratio of the precursor solution to the total volume of the electrolyte was 16:1. The precursor solution was cast onto a Teflon plate and exposed to a 365 nm UV beam at ambient temperature for 120 minutes. The electrolyte obtained in Comparative Example 2 had a molecular weight of 1.36×10 -4 Scm -1 , 6.12 x 10 at 60 °C -4 Scm -1 The ionic conductivity was .

[0123] The mechanical strength of the electrolyte obtained in Comparative Example 2 was tested by stress-strain measurement. As shown in Figure 16, the tensile strength of the electrolyte obtained in Comparative Example 2 was 6.19 KPa, and the Young's modulus was only 4.54 KPa.

[0124] Comparative Example 3 An all-solid-state lithium secondary battery consisting of a positive electrode, the electrolyte obtained in Comparative Example 1, and a lithium metal negative electrode was assembled under an argon atmosphere (O2, H2O<0.5 ppm). The positive electrode slurry was obtained by blending LiFePO4 (0.4 g) / Super-P (0.05 g) / PEO (0.05 g) / LiClO4 (0.0067 g) in a weight ratio of 78.94%:9.87%:9.87%:1.32% in acetonitrile, and then the slurry was directly loaded onto an aluminum foil by blade casting and dried under vacuum at 100° C. for 12 hours to remove the solvent.

[0125] FIG. 17 shows the rate performance of the all-solid-state lithium secondary battery at 60°C. The maximum discharge specific capacity of the battery at 0.1C, 0.2C, 0.5C, 1C, 2C and 3C was 162.1mAhg, respectively. -1 , 150.7mAhg -1 , 130.7mAhg -1 , 99mAhg -1, 56.5mAhg -1 , 38.6mAhg -1 This was significantly inferior to the maximum specific discharge capacity of Example 8.

[0126] The cycle performance of the all-solid-state lithium secondary battery was evaluated at 60°C and 0.1C. As shown in FIG. 18, the all-solid-state lithium secondary battery had a discharge capacity of 103 mAhg after 200 cycles. -1 , and capacity retention rate remained at 66.2%.

[0127] The main performance test results are summarized in Table 1 below.

[0128] [Table 1]

[0129] As shown in Table 1, when the weight ratio of siloxane monomer to EO-based monomer is decreased, the ionic conductivity of the electrolyte of the present invention increases, but the mechanical strength of the electrolyte decreases, which is contrary to the teaching of US Patent Application Publication No. 2003 / 0180624. + As the ratio of ionic conductivity increases from 14:1 to 18:1, the ionic conductivity of the electrolyte surprisingly peaks at 16:1. The electrolyte of the present invention has mechanical properties that are much better than the electrolyte of the comparative examples. In particular, in examples such as Examples 6 to 8, the electrolyte has an ionic conductivity comparable to that of the comparative examples, but has much better mechanical properties.

[0130] As shown in Example 6, a symmetric Li / electrolyte / Li battery containing the electrolyte of Example 6 had a current density of 0.1 mAcm at 60°C. -2The results show that the electrolyte has excellent interfacial stability with lithium metal and can effectively suppress lithium dendrites due to its excellent mechanical properties. In contrast, the Li / electrolyte / Li symmetric battery containing the electrolyte of Comparative Example 1 showed fluctuations after 800 hours and short circuits after 900 hours of cycling, indicating that the interfacial stability between the electrolyte and lithium metal obtained in Comparative Example 1 was far worse than that of Example 6 and was therefore poor.

[0131] As shown in Example 10, the all-solid-state lithium secondary battery containing the electrolyte of Example 6 had a capacity of 158.7 mAhg even after 200 cycles at 60° C. and 0.1 C. -1 The discharge capacity of the all-solid-state lithium secondary battery was still 103 mAhg after 200 cycles at 60° C. and 0.1 C, with a capacity retention rate of 97.6%, demonstrating the excellent cycle performance of the all-solid-state lithium cell. In contrast, as shown in Comparative Example 3, the all-solid-state lithium secondary battery containing the electrolyte of Comparative Example 1 had a discharge capacity of 103 mAhg after 200 cycles at 60° C. and 0.1 C. -1 However, the capacity retention rate was only 66.2%, which was far inferior to that of Example 6.

[0132] As used herein, terms used herein, such as "comprise(s)", are open terms meaning "including at least", unless otherwise specified.

[0133] All references, tests, standards, documents, publications, etc. mentioned herein are incorporated by reference. When a numerical limit or range is listed, the endpoints are included. Also, all values ​​and subranges within the numerical limit or range are specifically included as if expressly written out.

[0134] The above description is presented to enable any person skilled in the art to make and use the invention, and is provided in the context of a particular application and its requirements. Various modifications to the preferred embodiment will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein. In this regard, certain embodiments within the scope of the invention may not represent all of the advantages of the invention when considered broadly.

Claims

1. A monomer composition, wherein the monomer composition comprises, A) an alkylene oxide-based monomer; and B) a siloxane monomer and contains, consists essentially of, or consists of, wherein the siloxane monomer is a compound of formula (II) M １ ｅ M ３ ｆ D １ ｇ D ３ ｈ (II) wherein, M １ = [R １ ３ SiO １／２ , M ３ = [R １ ２ R ３ SiO １／２ , D １ = [R １ ２ SiO ２／２ , D ３ = [R １ R ３ SiO ２／２ , e = 2, f = 0, g = 0 to 38, h = 4 to 15, the ratio of the sum (f + h) to the sum (g + h + 2) is 0.15 to 1, the sum (g + h + 2) is 5 to 40, R １ represents the same or different aliphatic hydrocarbons having 1 to 10 carbon atoms, or aromatic hydrocarbons having 6 to 12 carbon atoms, R ３ represents the same or different hydrocarbons having 1 to 5 same or different esters, the hydrocarbons are linear, cyclic, branched and / or aromatic, the esters are (meth)acryloxy functional groups, and are selected from ethylenically unsaturated radical polymerizable esters and non-radical polymerizable ester groups, and the number of radically polymerizable groups in the siloxane monomer is 3 or more. A monomer composition.

2. The composition according to claim 1, wherein in the siloxane monomer, the radically polymerizable groups are present in a numerical ratio of 80 to 90% based on the total number of ester functional groups of the compound of formula (II).

3. The composition according to claim 1, wherein the weight ratio of the siloxane monomer to the alkylene oxide-based monomer is 1:0.4 to 1:

80.

4. The composition according to claim 1, wherein the alkylene oxide-based monomer is an EO-based monomer or a PO-based monomer.

5. The composition according to claim 1, wherein the alkylene oxide-based monomer is selected from EO-based (meth)acrylates and PO-based (meth)acrylates.

6. The composition according to claim 5, wherein the EO-based (meth)acrylate is selected from polyethylene glycol (meth)acrylate The composition according to claim 5, wherein the EO-based (meth)acrylate is selected from polyethylene glycol (meth)acrylate.

7. A copolymerized polymer electrolyte precursor composition for producing a solid polymer electrolyte, wherein the copolymerized polymer electrolyte precursor composition comprises I) the monomer composition according to claim 1; II) a lithium salt; and optionally III) a free radical initiator for the polymerization reaction A composition comprising.

8. The molar ratio AO / Li of the alkylene oxide monomer and the lithium salt ＋ is (12 to 20):1, and the composition according to claim 7.

9. A method for producing a solid copolymerized polymer electrolyte, comprising a) mixing the copolymerized polymer electrolyte precursor composition according to claim 7 containing a free radical initiator under a protective atmosphere until a homogeneous viscous liquid is formed; and b) curing the liquid under UV irradiation or heating A method comprising.

10. The method according to claim 9, wherein the chemical materials of the method contain a solvent in an amount of 0 to 10% by weight in total based on the total weight of the chemical materials used in the method.

11. A solid copolymerized polymer electrolyte, wherein the solid copolymerized polymer electrolyte comprises - a copolymer of the monomer composition according to any one of claims 1 to 6, and - a lithium salt and contains; A solid copolymer polymer electrolyte, or the electrolyte is produced by the method according to claim 9.

12. A solid lithium secondary battery, comprising a positive electrode, a solid copolymer polymer electrolyte, and a negative electrode, wherein the solid copolymer polymer electrolyte is the solid copolymer polymer electrolyte according to claim 11.

13. A method for manufacturing a solid lithium secondary battery, comprising the step of assembling a positive electrode, the solid copolymer polymer electrolyte according to claim 11, and a negative electrode to form a solid lithium secondary battery. A method as described above.

14. An electrochemical device comprising the solid copolymer polymer electrolyte according to claim 11.

15. A device comprising the electrochemical device according to claim 14.

16. Use of the monomer composition according to any one of claims 1 to 6, or use of the copolymer polymer electrolyte precursor composition according to claim 7, in the manufacture of a solid polymer electrolyte of a lithium secondary battery.

17. A copolymer of the monomer composition according to any one of claims 1 to 6.

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