Polymer electrolyte separator, preparation method therefor, and use thereof

Abstract

A polymer electrolyte separator, a preparation method therefor, and a use thereof. The polymer electrolyte separator comprises an electrolyte salt, a polymer, and an inorganic filler modified by a modifying agent. The modifying agent comprises one or more of: 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, [8-(glycidyloxy)-n-octyl]trimethylsilane, dimethoxymethyl-3-methoxypropylsilane, 3-glycidyloxypropyldimethylethoxysilane, and a vinyl silane coupling agent. The polymer electrolyte separator has both excellent electrical conductivity and structural stability, facilitating improvement of the electrochemical performance and cycle life of batteries.

Description

Polymer electrolyte separator, preparation method and application thereof

[0001] This application claims priority to the Chinese patent application No. 202411367960.1, filed on September 27, 2024, and entitled "Polymer electrolyte separator, preparation method and application thereof", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the field of batteries, in particular to a polymer electrolyte separator, a preparation method and application thereof. BACKGROUND

[0003] At present, the polymer electrolyte separator has high safety, which can improve the service life and safety of the battery. Compared with the traditional inorganic solid electrolyte, the polymer electrolyte has low ionic conductivity and poor structural stability. In the related art, inorganic fillers can be added to the polymer electrolyte separator to promote the dissociation of the electrolyte salt, thereby improving the conductivity of the polymer electrolyte separator. However, in the prior art, the addition of inorganic fillers has limited improvement on the conductivity of the polymer electrolyte separator, and the film-forming performance of the polymer electrolyte separator is reduced when a high content of inorganic fillers is added, resulting in a decrease in the cycle life of the battery. Therefore, there is a need for a polymer electrolyte film that has excellent conductivity and good structural reliability. SUMMARY

[0004] In view of this, the present application provides a polymer electrolyte separator, a preparation method and application thereof. The polymer electrolyte separator comprises a polymer, an inorganic filler modified by a modifier and an electrolyte salt. The polymer electrolyte separator has excellent conductivity and structural stability.

[0005] In a first aspect, the present application provides a polymer electrolyte separator, which comprises an electrolyte salt, a polymer and an inorganic filler modified by a modifier. The modifier comprises one or more of 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, [8-(epoxypropyloxy)-n-octyl]trimethylsilane, dimethoxymethyl-3-methoxypropylsilane, 3-epoxypropoxypropyldimethylethoxysilane and vinyl silane coupling agent.

[0006] Optionally, the vinyl silane coupling agent includes one or more of triethyl vinyl silane, vinyl trimethoxysilane, dimethyl divinyl silane, triphenyl vinyl silane, dimethoxy methyl vinyl silane, dimethyl ethoxy vinyl silane, vinyl triethoxysilane, methyl bis(trimethylsiloxy) vinyl silane, triallyl (methyl) silane, methyl vinyl diethoxysilane, vinyl trimethyl silane, (2-methylallyl) trimethyl silane, tri(isoallyloxy) vinyl silane, allyl triethoxysilane, diallyl dimethyl silane, diethyl methyl vinyl silane, 3-buten-1-yl (trimethylsilyl), triallyl (phenyl) silane, vinyl tris(trimethylsiloxy) silane, triacetoxy (vinyl) silane, and vinyl tris(2-methoxyethoxy) silane.

[0007] Optionally, a covalent bond is formed between the polymer and the modified inorganic filler of the modifying agent.

[0008] Optionally, in the modified inorganic filler of the modifying agent, the grafting rate of the modifying agent is 0.5% to 10%.

[0009] Optionally, the mass ratio of the modified inorganic filler of the modifying agent, the electrolyte salt, and the polymer is (0.01-0.8):(0.3-0.55):1.

[0010] Optionally, the modified inorganic filler of the modifying agent includes one or more of a modified oxide solid electrolyte and a modified metal oxide.

[0011] Optionally, the oxide solid electrolyte includes one or more of lithium lanthanum zirconium oxide, lithium lanthanum zirconium tantalum oxide, lithium vanadium oxide, lithium boron oxide, lithium lanthanum titanium oxide, and lithium strontium titanium oxide, and / or the metal oxide includes one or more of aluminum trioxide and silicon dioxide.

[0012] Optionally, the structural formula of the polymer is wherein R is a hydroxyl group, an amino group, or a mercapto group, n is 0.6-0.9, m is 0.1-0.4, and n+m=1.

[0013] Optionally, in the polymer, the weight average molecular weight of the polymer is 100000-1000000.

[0014] Optionally, the electrolyte salt includes a lithium salt.

[0015] Optionally, the lithium salt includes one or more of a first lithium salt and a second lithium salt, the first lithium salt includes one or more of lithium bis(trifluoromethanesulfonyl) imide, lithium bisfluorosulfonylimide, and lithium bis(oxalato) borate, and the second lithium salt includes one or more of lithium tetrafluoroborate and lithium hexafluorophosphate.

[0016] Optionally, the lithium salt comprises a first lithium salt and a second lithium salt, wherein the mass percentage of the first lithium salt is 99-99.9% and the mass percentage of the second lithium salt is 0.1-1%, based on the total mass of the lithium salt.

[0017] Optionally, the Young's modulus of the polymer electrolyte separator is 1-30 MPa.

[0018] The polymer electrolyte film provided by the application comprises a polymer, a modified inorganic filler and an electrolyte salt, and the conductivity and structural stability of the polymer electrolyte separator are improved.

[0019] In a second aspect, the application provides a preparation method of a polymer electrolyte film, comprising:

[0020] The inorganic filler is modified to obtain a modified inorganic filler;

[0021] The polymer, the electrolyte salt and the modified inorganic filler are mixed, and then dried and formed to obtain a polymer electrolyte separator.

[0022] Optionally, the mass ratio of the inorganic filler to the modifier is 1:(0.01-0.1).

[0023] Optionally, the mass ratio of the modified inorganic filler, the electrolyte salt and the polymer is (0.01-0.8):(0.3-0.55):1.

[0024] The preparation method of the polymer electrolyte film provided by the application is novel, the preparation process is simple, and the prepared product has excellent performance.

[0025] In a third aspect, the application provides a battery, which comprises a positive electrode sheet and a negative electrode sheet, and a polymer electrolyte separator of the first aspect or prepared by the preparation method of the second aspect arranged between the positive electrode sheet and the negative electrode sheet.

[0026] The battery provided by the application has good safety performance, high cycle stability and long cycle life.

[0027] In a fourth aspect, the application provides an electrical equipment, which comprises the battery of the third aspect.

[0028] The electrical equipment provided by the application has excellent comprehensive performance and strong product competitiveness. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced. The specific embodiments described herein are only used to explain the present application, and are not used to limit the present application.

[0030] Fig. 1 is a schematic diagram of the cross-sectional structure of a battery provided by an embodiment of the present application. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described in combination with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0032] The present application provides a polymer electrolyte separator, which comprises an electrolyte salt, a polymer and an inorganic filler modified by a modifier, the modifier comprising one or more of 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, [8-(epoxypropyloxy)-n-octyl]trimethylsilane, dimethoxymethyl-3-methoxypropylsilane, 3-epoxypropoxypropyldimethylethoxysilane and vinylsilane coupling agent. In the present application, the polymer has good film-forming properties, which is conducive to improving the film-forming properties of the polymer electrolyte separator; the inorganic filler modified by the modifier has an epoxy group, so that the polymer and the inorganic filler modified by the modifier are covalently bonded and crosslinked, forming a polymer network structure with the inorganic filler modified by the modifier as the crosslinking center, which has good high-temperature stability, the formed polymer network structure can transport lithium ions, and the ionic conductivity of the polymer electrolyte separator is improved; the electrolyte salt is dispersed in the polymer network structure, which can reduce the water content in the polymer electrolyte separator, improve the ionic conductivity and stability of the polymer electrolyte separator, and is conducive to improving the cycle safety of the battery. The polymer electrolyte separator provided by the present application can simultaneously serve as the electrolyte and the separator of the battery, has good structural stability and high conductivity, and when applied to a solid-state battery, can improve the electrochemical performance and cycle life of the solid-state battery.

[0033] In an embodiment of the present application, the inorganic filler modified by the modifying agent has epoxy groups, which can react with the polymer to form a crosslinking network. Specifically, the inorganic filler modified by the modifying agent can include, but is not limited to, one or more of a modifying agent modified oxide solid electrolyte and a modifying agent modified metal oxide; for example, the oxide solid electrolyte can include, but is not limited to, one or more of lithium lanthanum zirconium oxide, lithium lanthanum zirconium tantalum oxide, lithium vanadium oxide, lithium boron oxide, lithium lanthanum titanium oxide, and lithium strontium titanium oxide, and the metal oxide can include, but is not limited to, one or more of aluminum trioxide and silicon dioxide. In an embodiment of the present application, the inorganic filler modified by the modifying agent can be a modifying agent modified lithium lanthanum zirconium oxide. In another embodiment of the present application, the inorganic filler modified by the modifying agent can be a modifying agent modified aluminum trioxide.

[0034] In the present application, the surface of the inorganic filler is modified by forming hydroxyl groups on the surface of the inorganic filler during the preparation process, and the structure of the hydroxyl groups is prone to react with the silicon-oxygen structure of the modifying agent to form a covalent bond, which is conducive to the formation of a subsequent crosslinking network. Specifically, the modifying agent can include, but is not limited to, one or more of 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, [8-(epoxypropyloxy)-n-octyl]trimethylsilane, dimethoxymethyl-3-methoxypropylsilane, 3-epoxypropoxypropyldimethylethoxysilane, and vinyl silane coupling agent. In an embodiment of the present application, the modifying agent can be a vinyl silane coupling agent, in which case, the carbon-carbon double bond in the vinyl group of the vinyl silane coupling agent needs to be oxidized to an epoxy group after the inorganic filler is modified by the modifying agent. The oxidation method can include, but is not limited to, one or more of hydrogen peroxide catalytic oxidation and oxygen catalytic oxidation. The vinyl silane coupling agent can increase the reaction sites of the modifying agent and the polymer, while reducing the occurrence of side reactions, which is conducive to the occurrence of the modification reaction.

[0035] In an embodiment of the present application, the vinyl silane coupling agent can include, but is not limited to, one or more of triethyl vinyl silane, vinyl trimethoxysilane, dimethyl divinyl silane, triphenyl vinyl silane, dimethoxy methyl vinyl silane, dimethyl ethoxy vinyl silane, vinyl triethoxysilane, methyl bis(trimethylsiloxy) vinyl silane, triallyl (methyl) silane, methyl vinyl diethoxysilane, vinyl trimethyl silane, (2-methylallyl) trimethyl silane, tri(iso-allyloxy) vinyl silane, allyl triethoxysilane, diallyl dimethyl silane, diethyl methyl vinyl silane, 3-buten-1-yl (trimethylsiloxy), triallyl (phenyl) silane, vinyl tri(trimethylsiloxy) silane, triacetoxy (vinyl) silane, and vinyl tri(2-methoxyethoxy) silane. In an embodiment of the present application, the vinyl silane coupling agent can be methyl bis(trimethylsiloxy) vinyl silane. In another embodiment of the present application, the vinyl silane coupling agent can be tri(iso-allyloxy) vinyl silane.

[0036] In an embodiment of the present application, in the composite of the polymer and the inorganic filler, the surface of the inorganic filler modified by the modifier forms a grafted structure through chemical bonding. The grafting rate of the modifier refers to the proportion of the mass of the modifier to the total mass of the inorganic filler modified by the modifier. In an embodiment of the present application, the grafting rate of the modifier in the inorganic filler modified by the modifier is 0.5% to 10%. A suitable grafting rate can improve the interfacial interaction between the polymer and the surface of the inorganic filler modified by the modifier, which is beneficial to improving the dispersibility and lipophilicity of the inorganic filler modified by the modifier, and increasing the reaction sites of the polymer and the inorganic filler modified by the modifier. Specifically, the grafting rate of the modifier can be, but is not limited to, 0.5%, 1%, 2%, 4%, 6%, 8%, or 10%, etc. In an embodiment of the present application, the grafting rate of the modifier can be 0.5% to 7%. In another embodiment of the present application, the grafting rate of the modifier can be 5% to 10%.

[0037] In an embodiment of the present application, the structural formula of the polymer is wherein R is hydroxyl, amino or sulfydryl, n is 0.6-0.9, m is 0.1-0.4, and n+m=1. The epoxy groups in the modified inorganic filler and the hydroxyl, amino or sulfydryl in the polymer crosslink to form a polymer crosslinking network; meanwhile, the side chains in the polymer can transport lithium ions, which is conducive to the movement of lithium ions in the polymer crosslinking network, and improves the ionic conductivity of the polymer electrolyte separator. n and m represent the molar proportion of the corresponding structural units. Specifically, n can be but is not limited to 0.6, 0.65, 0.7, 0.75, 0.8, 0.85 or 0.9, and m can be but is not limited to 0.1, 0.15, 0.2, 0.25, 0.3, 0.35 or 0.4. In an embodiment of the present application, n can be 0.6-0.8, and m can be 0.2-0.4. In another embodiment of the present application, n can be 0.7-0.9, and m can be 0.1-0.3.

[0038] In an embodiment of the present application, the molar ratio of n to m in the polymer is (6-9):(1-4). Specifically, the molar ratio of n to m in the polymer can be but is not limited to 6:4, 7:3, 8:2 or 9:1. In an embodiment of the present application, the molar ratio of n to m in the polymer is (6-8):(2-4). In another embodiment of the present application, the molar ratio of n to m in the polymer is (7-9):(1-3).

[0039] In an embodiment of the present application, the weight average molecular weight of the polymer is 100000-1000000. The polymer with high molecular weight has excellent film-forming property, and can form a self-supporting polymer electrolyte separator, thereby improving the structural stability of the polymer electrolyte separator. Specifically, the weight average molecular weight of the polymer can be but is not limited to 100000, 120000, 150000, 180000, 200000, 220000, 250000, 280000 or 1000000. In an embodiment of the present application, the weight average molecular weight of the polymer can be 100000-500000. In another embodiment of the present application, the weight average molecular weight of the polymer can be 300000-1000000.

[0040] In an embodiment of the present application, the electrolyte salt comprises a lithium salt, and the lithium salt comprises at least one of a first lithium salt and a second lithium salt. The first lithium salt can improve the conductivity of the polymer electrolyte separator, and the second lithium salt can act as a catalyst to promote the cross-linking reaction between the modified inorganic filler and the polymer in a water-containing environment, form a polymer cross-linking network, and reduce the water content in the polymer electrolyte separator, thereby improving the cycle stability of the battery. Specifically, the first lithium salt can include, but is not limited to, one or more of lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, and lithium bis(oxalato)borate; and the second lithium salt can include, but is not limited to, one or more of lithium tetrafluoroborate and lithium hexafluorophosphate. In an embodiment of the present application, the first lithium salt can be lithium bis(trifluoromethanesulfonyl)imide, and the second lithium salt can be lithium tetrafluoroborate. In another embodiment of the present application, the first lithium salt can be lithium bis(oxalato)borate, and the second lithium salt can be lithium hexafluorophosphate.

[0041] In an embodiment of the present application, the lithium salt comprises a first lithium salt and a second lithium salt, and the mass percentage of the first lithium salt is 99%-99.9% and the mass percentage of the second lithium salt is 0.1%-1%, based on the total mass of the lithium salt. The first lithium salt as the main electrolyte salt in the polymer electrolyte separator is beneficial to improve the conductivity of the polymer electrolyte separator, and a small amount of the second lithium salt can act as a catalyst to promote the cross-linking reaction between the modified inorganic filler and the polymer in a water-containing environment, form a polymer cross-linking network, reduce the water content in the polymer electrolyte separator, and improve the cycle stability of the battery. Specifically, the mass percentage of the first lithium salt can include, but is not limited to, 99%, 99.2%, 99.4%, 99.6%, 99.8%, or 99.9%, and the mass percentage of the second lithium salt can include, but is not limited to, 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, or 1%. In an embodiment of the present application, the mass percentage of the first lithium salt can be 99%-99.6%, and the mass percentage of the second lithium salt can be 0.4%-1%. In another embodiment of the present application, the mass percentage of the first lithium salt can be 99.5%-99.9%, and the mass percentage of the second lithium salt can be 0.1%-0.5%.

[0042] In an embodiment of the present application, the mass ratio of the modified inorganic filler, the electrolyte salt and the polymer modified by the modifier is (0.01-0.8):(0.3-0.55):1, and the appropriate mass ratio can make the polymer electrolyte separator have high conductivity and high structural stability. Specifically, the mass ratio of the modified inorganic filler, the electrolyte salt and the polymer modified by the modifier can be, but is not limited to, 0.01:0.3:1, 0.05:0.32:1, 0.1:0.35:1, 0.2:0.36:1, 0.4:0.38:1, 0.5:0.4:1, 0.6:0.45:1, 0.7:0.5:1 or 0.8:0.55:1, etc. In an embodiment of the present application, the mass ratio of the modified inorganic filler, the electrolyte salt and the polymer modified by the modifier can be (0.01-0.5):(0.3-0.45):1. In another embodiment of the present application, the mass ratio of the modified inorganic filler, the electrolyte salt and the polymer modified by the modifier can be (0.4-0.8):(0.4-0.55):1.

[0043] In an embodiment of the present application, the thickness of the polymer electrolyte separator is 30-100 μm. Specifically, the thickness of the polymer electrolyte separator can be, but is not limited to, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm or 100 μm. In an embodiment of the present application, the thickness of the polymer electrolyte separator can be 30-80 μm. In another embodiment of the present application, the thickness of the polymer electrolyte separator can be 50-100 μm.

[0044] In an embodiment of the present application, the Young's modulus of the polymer electrolyte separator is 1-30 MPa, which is beneficial to improve the structural reliability of the polymer electrolyte separator and improve the safe use performance of the battery. Specifically, the Young's modulus of the polymer electrolyte separator can be, but is not limited to, 1 MPa, 5 MPa, 10 MPa, 15 MPa, 20 MPa, 25 MPa or 30 MPa, etc. In an embodiment of the present application, the Young's modulus of the polymer electrolyte separator can be 1-20 MPa. In another embodiment of the present application, the Young's modulus of the polymer electrolyte separator can be 15-30 MPa.

[0045] The present application also provides a preparation method of a polymer electrolyte separator, comprising:

[0046] The inorganic filler is modified to obtain a modified inorganic filler modified by a modifier;

[0047] The polymer, electrolyte salt and the modified inorganic filler are mixed, and after drying and molding, a polymer electrolyte separator is obtained. The preparation method provided in the application is novel, the preparation process is simple, the structure of the polymer electrolyte separator prepared has strong reliability and good conductivity, and the cycle life and electrochemical performance of the battery are improved.

[0048] In an embodiment of the application, the modifier can react with the hydroxyl structure in the inorganic filler, so that the modifier is grafted to the surface of the inorganic filler, which is conducive to the formation of a subsequent crosslinked network. Specifically, the modifier can be, but is not limited to, one or more of 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, [8-(glycidoxy)-n-octyl]trimethylsilane, dimethoxymethyl-3-methoxypropylsilane, 3-glycidoxypropyldimethylethoxysilane and vinyl silane coupling agent. In an embodiment of the application, the modifier can be a vinyl silane coupling agent. At this time, after the vinyl silane coupling agent is modified on the inorganic filler, the carbon-carbon double bond in the alkenyl group needs to be oxidized to an epoxy group. The oxidation method can be, but is not limited to, one or more of hydrogen peroxide catalytic oxidation and oxygen catalytic oxidation.

[0049] In an embodiment of the application, the vinyl silane coupling agent can be, but is not limited to, one or more of triethylvinylsilane, vinyltrimethoxysilane, dimethyldivinylsilane, triphenylvinylsilane, dimethoxymethylvinylsilane, dimethylethoxylvinylsilane, vinyltriethoxysilane, methylbis(trimethylsiloxy)vinylsilane, triallyl(methyl)silane, methylvinyl-diethoxysilane, vinyltrimethylsilane, (2-methylallyl)trimethylsilane, tris(isoallyloxy)vinylsilane, allyltriethoxysilane, diallyldimethylsilane, diethylmethylvinylsilane, 3-buten-1-yl(trimethylsilane), triallyl(phenyl)silane, vinyltris(trimethylsiloxy)silane, triacetoxy(vinyl)silane and vinyltris(2-methoxyethoxy)silane. In an embodiment of the application, the vinyl silane coupling agent can be methylbis(trimethylsiloxy)vinylsilane. In another embodiment of the application, the vinyl silane coupling agent can be tris(isoallyloxy)vinylsilane.

[0050] In an embodiment of the present application, the mass ratio of the inorganic filler and the modifier is 1:(0.01-0.1). The appropriate mass ratio of the inorganic filler and the modifier can promote the modification reaction of the inorganic filler, and the modified inorganic filler prepared by the modifier has good cross-linking performance, which is beneficial to form a polymer electrolyte separator with excellent film-forming performance. Specifically, the mass ratio of the inorganic filler and the modifier can be, but is not limited to, 1:0.01, 1:0.02, 1:0.05, 1:0.06, 1:0.07, 1:0.08, 1:0.09, or 1:0.1, etc. In an embodiment of the present application, the mass ratio of the inorganic filler and the modifier can be 1:(0.01-0.05). In another embodiment of the present application, the mass ratio of the inorganic filler and the modifier can be 1:(0.03-0.1).

[0051] In an embodiment of the present application, the inorganic filler and the modifier are mixed, the mixing temperature is 40-80°C, and the mixing time is 10-60 min. Specifically, the mixing temperature can be, but is not limited to, 40°C, 50°C, 60°C, 70°C, or 80°C, and the mixing time can be, but is not limited to, 10 min, 20 min, 30 min, 40 min, 50 min, or 60 min, etc. In an embodiment of the present application, the inorganic filler and the modifier are mixed, the mixing temperature can be 60-80°C, and the mixing time can be 10-40 min. In another embodiment of the present application, the inorganic filler and the modifier are mixed, the mixing temperature can be 70-100°C, and the mixing time can be 30-60 min.

[0052] In an embodiment of the present application, the inorganic filler, the modifier, and the solvent are mixed to form a mixture, which is beneficial to the sufficient contact of the inorganic filler and the modifier and the synthesis of the modified inorganic filler by the modifier. Specifically, the solvent can be one or more of toluene, acetone, butanone, N.N-dimethylformamide, N-methyl pyrrolidone, dimethyl sulfoxide, methanol, ethanol, isopropyl alcohol, and n-butanol. In an embodiment of the present application, the solvent can be toluene, 2 g of inorganic filler is dissolved in 20 ml of toluene to form a toluene solution containing inorganic filler, 3-glycidyl ether oxypropyl trimethoxysilane is dissolved in toluene to prepare a 10% toluene solution containing a modifier, and the toluene solution containing the inorganic filler and the toluene solution containing the modifier are mixed to form a mixture.

[0053] In an embodiment of the present application, before the inorganic filler, the modifier, and the solvent are mixed, the inorganic filler is also washed. Specifically, the inorganic filler raw material is placed in a 0.1 mol / L sodium hydroxide solution, soaked for 30 min, and filtered and washed to obtain the inorganic filler.

[0054] In an embodiment of the present application, the inorganic filler and the modifier are mixed, and after reaction, drying treatment is performed, the temperature of the drying treatment is 50-130 DEG C, and the time of the drying treatment is 4-8 hours. Specifically, the temperature of the drying treatment can be but is not limited to 50 DEG C, 60 DEG C, 80 DEG C, 100 DEG C or 130 DEG C, and the time of the drying treatment can be but is not limited to 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours or 8 hours. In an embodiment of the present application, the temperature of the normal-pressure drying treatment can be 110-130 DEG C, and the time of the drying treatment can be 4-7 hours. In another embodiment of the present application, the temperature of the vacuum drying treatment can be 50-80 DEG C, and the time of the drying treatment can be 6-8 hours.

[0055] In an embodiment of the present application, the polymer, the electrolyte salt and the inorganic filler modified by the modifier are mixed, the temperature of the mixing is 40-80 DEG C, and the time of the mixing is 6-8 hours. Specifically, the temperature of the mixing can be but is not limited to 40 DEG C, 50 DEG C, 60 DEG C, 70 DEG C or 80 DEG C, and the time of the mixing can be but is not limited to 6 hours, 6.5 hours, 7 hours, 7.5 hours or 8 hours. In an embodiment of the present application, the polymer, the electrolyte salt and the inorganic filler modified by the modifier are mixed, the temperature of the mixing can be 40-60 DEG C, and the time of the mixing can be 6-7.5 hours. In another embodiment of the present application, the polymer is dissolved in acetonitrile solution, the inorganic filler modified by the modifier is added and stirred for 6 hours, and then the electrolyte salt is added and mixed at 60 DEG C for 1 hour.

[0056] Referring to FIG. 1, a schematic diagram of a cross-sectional structure of a battery provided in an embodiment of the present application is shown, the battery 100 includes a positive electrode sheet 10 and a negative electrode sheet 12, and the polymer electrolyte separator 11 described in any one of the above embodiments is arranged in the positive electrode sheet 10 and the negative electrode sheet 12. The battery provided in the present application has a polymer electrolyte separator with excellent structural stability and good conductivity, which improves the service life, cycle stability and electrochemical performance of the battery.

[0057] The present application also provides a power-consuming device, which includes the battery provided in any one of the above embodiments. The power-consuming device provided in the present application has excellent comprehensive performance and strong market competitiveness. The power-consuming device of the present application can be a vehicle, an electronic device, an energy storage system, etc., and the above electrochemical device can be arranged in the power-consuming device in the form of a single battery, a battery module, a battery pack, a capacitor, etc. In an embodiment of the present application, the battery can be used in a vehicle, which can improve the safety of the power consumption of the vehicle. In another embodiment of the present application, the battery can also be applied to an electronic device, which can increase the high-temperature cycle stability of the battery of the electronic device and improve the service life of the battery.

[0058] The effects of the technical solutions of the present application are further described below through specific examples.

[0059] Example 1

[0060] 2 g of inorganic filler raw material (nano-silica) was added to a 0.1 mol / L sodium hydroxide solution, soaked for 30 min, and after filtration and washing, the inorganic filler was obtained. The inorganic filler was added to 20 ml of toluene, and ultrasonic dispersion was performed to obtain an inorganic filler-containing solution. A modifier (dimethoxymethyl-3-methoxypropylsilane) was dissolved in toluene to prepare a 10% modifier-containing solution. 2 ml of the 10% modifier-containing solution was mixed with the inorganic filler-containing solution. After stirring at 80°C in a four-necked flask connected with a reflux condenser for 30 min, centrifugal washing was performed three times at a rotation speed of 16000 rpm, and vacuum drying was performed at 60°C for 6 h to obtain the inorganic filler modified with the modifier.

[0061] The polymer (weight average molecular weight 600000) was dissolved in an acetonitrile solution, and the inorganic filler modified with the modifier was added and stirred for 6 h. After adding an electrolyte salt (99.5% lithium bis(trifluoromethanesulfonyl)imide and 0.5% lithium tetrafluoroborate by mass percentage), stirring was performed at 60°C for 1 h to obtain a polymer electrolyte solution. The solvent was volatilized by pouring the solution into a polytetrafluoroethylene mold to obtain a polymer electrolyte separator having a thickness of 50 μm. The mass ratio of the inorganic filler modified with the modifier, the electrolyte salt, and the polymer was 0.3:0.4:1, and the structural formula of the polymer was R is a hydroxyl group, n = 0.6, and m = 0.4.

[0062] Example 2

[0063] The difference from Example 1 is that the modifier (3-glycidyl ether oxypropyl trimethoxysilane) was dissolved in toluene to prepare a 5% modifier-containing solution.

[0064] Example 3

[0065] The difference from Example 1 is that the mass ratio of the inorganic filler modified with the modifier, the electrolyte salt, and the polymer was 0.8:0.55:1.

[0066] Example 4

[0067] The difference from Example 1 is that the mass ratio of the inorganic filler modified with the modifier, the electrolyte salt, and the polymer was 0.01:0.3:1.

[0068] Example 5

[0069] The difference from Example 1 is that the structural formula of the polymer (weight average molecular weight 600000) was R is a hydroxyl group, n = 0.9, and m = 0.1.

[0070] Example 6

[0071] The difference from Example 1 is that the electrolyte salt is lithium bis(trifluoromethanesulfonyl)imide with a mass percentage of 100%.

[0072] Example 7

[0073] The difference from Example 1 is that the modifier is triethyl vinylsilane, and the modified product is subjected to catalytic oxidation treatment.

[0074] Comparative Example 1

[0075] The difference from Example 1 is that the inorganic filler is not subjected to modification treatment.

[0076] Comparative Example 2

[0077] The difference from Example 1 is that 2 ml of modifier γ-methacryloyloxypropyl trimethoxysilane (KH570), 2 ml of acetic acid, 4 ml of deionized water and 72 ml of methanol are mixed in a beaker for 1 h to obtain a modifier-containing solution, 1.2 g of inorganic filler is added to the above modifier-containing solution, and after stirring at 70°C for 6 h, it is washed with ethanol for 3 times and vacuum dried for 24 h to obtain a modified inorganic filler;

[0078] 10 g of polyethylene oxide (PEO) with a weight average molecular weight of 600,000 g / mol, 6.73 g of lithium bis(trifluoromethanesulfonyl)imide (LITFSI) and 1 g of modified inorganic filler are added to 90 g of acetonitrile solution, stirred at 60°C for 6 h to obtain a polymer electrolyte solution, which is poured into a polytetrafluoroethylene mold to volatilize the solvent, and a polymer electrolyte separator with a thickness of 50 μm is obtained.

[0079] Performance detection

[0080] The Young's modulus of the polymer electrolyte separator provided by Examples 1-7 and Comparative Examples 1-2 is measured, and the test process is as follows:

[0081] The test results are shown in Table 1.

[0082] The grafting rate of the modifier-modified inorganic filler prepared in the above Examples 1-7 and Comparative Examples 1-2 is tested, and the test process is as follows: a certain amount of dried modifier-modified inorganic filler is taken and its weight is recorded, a crucible is placed in a muffle furnace and calcined to a constant weight, the weighed modifier-modified inorganic filler is placed in the crucible and calcined in the muffle furnace at 600°C for 7 h, and finally the calcined modifier-modified inorganic filler is weighed and recorded. The test method of grafting rate is ω = (M-m) / m x 100%, wherein ω (%) is the grafting rate, m (g) is the mass of the calcined modifier-modified inorganic filler, and M (g) is the mass of the modifier-modified inorganic filler before calcination. The test results are shown in Table 1.

[0083] The polymer electrolyte separators prepared in the above Examples 1-7 and Comparative Examples 1-2 were assembled into CR2025 button cells (blocked cells, blocked cell structure: metal / electrolyte separator / metal, the metal is usually stainless steel) in an argon-filled glove box (O2content ≤0.5 ppm, H2O content ≤0.5 ppm), wherein the electrode tab was a 10 μm copper foil.

[0084] The blocked cells prepared in the above Examples 1-7 and Comparative Examples 1-2 were subjected to ion conductivity testing, the testing process: 10 blocked cells were taken, and the blocked cells were subjected to alternating current impedance testing at a frequency range of 10 Hz to 300 KHz at 60±1 ℃ on an Autolab PGSTAT 302N electrochemical workstation. After the impedance spectrum was fitted, the intersection of the inclined line and the horizontal axis was taken as the bulk impedance of the electrolyte material. The ion conductivity calculation formula was δ = L / (R×S), wherein δ (S·cm-1) was the ion conductivity, L (cm) was the thickness of the polymer electrolyte membrane, S (cm2) was the effective contact area of the polymer electrolyte membrane and the copper foil, and R (Ω) was the intrinsic impedance. The test results are shown in Table 1. -2 ) for ion conductivity, L (cm) for the thickness of the polymer electrolyte membrane, S (cm2) for the effective contact area of the polymer electrolyte membrane and the copper foil, and R (Ω) for the intrinsic impedance. The test results are shown in Table 1.

[0085] The polymer electrolyte separators prepared in the above Examples 1-7 and Comparative Examples 1-2 were assembled into CR2025 button cells (full cells) in an argon-filled glove box (O2content ≤0.5 ppm, H2O content ≤0.5 ppm), wherein the positive electrode tab was a lithium iron phosphate tab, and the negative electrode tab was a 25 μm lithium foil.

[0086] The full cells prepared in the above Examples 1-7 and Comparative Examples 1-2 were subjected to cycle testing, the testing process: 10 full cells were taken, and the full cells were subjected to charge-discharge cycle testing at 0.5C at 60±1 ℃ on a LAND CT 2001C secondary battery performance testing device. Specifically, the full cells were left to stand for 5 min; constant current charged to 3.8 V cut-off; left to stand for 5 min; constant current discharged to 2.7 V, which was 1 cycle. The steps were repeated, and when the battery capacity was lower than 80% of the initial discharge capacity during the cycle, the cycle was terminated, and the cycle number was the cycle life of the full cell. The test results are shown in Table 1.

[0087] Table 1 Performance test results

[0088] According to the examples 1-7 and the comparative examples 1-2 of the present application, it can be seen that the polymer electrolyte separator provided by the present application includes the inorganic filler modified by the modifier, forms the polymer network structure with the inorganic filler modified by the modifier as the crosslinking center, has excellent conductivity, good high-temperature stability and high structural stability. According to the examples 1 and 2-7, it can be seen that the suitable modifier, the mass ratio of the inorganic filler modified by the modifier, the electrolyte salt and the polymer, the structure of the polymer and the type of the electrolyte salt are beneficial to improve the grafting rate of the inorganic filler modified by the modifier, improve the ionic conductivity of the polymer electrolyte separator and improve the cycle life of the battery. According to the examples 1 and the comparative example 1, it can be seen that the inorganic filler modified by the modifier can greatly improve the ionic conductivity of the polymer electrolyte separator and improve the cycle life of the battery. According to the examples 1 and the comparative example 2, it can be seen that the inorganic filler modified by the modifier provided by the present application can improve the ionic conductivity of the polymer electrolyte separator, and further improve the cycle life of the battery.

[0089] The above is the preferred embodiment of the present application, but it cannot be understood as the limitation of the scope of the present application. It should be pointed out that for ordinary skilled in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements are also considered as the protection scope of the present application.

Claims

1. A polymer electrolyte separator, wherein, The polymer electrolyte separator comprises an electrolyte salt, a polymer and a modifier-modified inorganic filler, the modifier comprises one or more of 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, [8-(epoxypropyloxy)-n-octyl]trimethylsilane, dimethoxymethyl-3-methoxypropylsilane, 3-epoxypropoxypropyldimethylethoxysilane and a vinyl silane coupling agent.

2. The polymer electrolyte separator of claim 1, wherein, The vinyl silane coupling agent comprises one or more of triethylvinylsilane, vinyltrimethoxysilane, dimethyldivinylsilane, triphenylvinylsilane, dimethoxymethylvinylsilane, dimethylethoxyvinylsilane, vinyltriethoxysilane, methylbis(trimethylsiloxy)vinylsilane, triallyl(methyl)silane, methylvinyl-diethoxysilane, vinyltrimethylsilane, (2-methylallyl)trimethylsilane, tris(isoallyloxy)vinylsilane, allyltriethoxysilane, diallyldimethylsilane, diethylmethylvinylsilane, 3-buten-1-yl(trimethylsilane), triallyl(phenyl)silane, vinyltris(trimethylsiloxy)silane, triacetoxy(vinyl)silane and vinyltris(2-methoxyethoxy)silane.

3. The polymer electrolyte membrane of claim 1, wherein, Covalent bonding is formed between the polymer and the modifier-modified inorganic filler.

4. The polymer electrolyte membrane of claim 3, wherein, In the modifier-modified inorganic filler, the grafting rate of the modifier is 0.5% to 10%.

5. The polymer electrolyte membrane of claim 1, wherein, The mass ratio of the modifier-modified inorganic filler, the electrolyte salt and the polymer is (0.01-0.8):(0.3-0.55):

1.

6. The polymer electrolyte membrane of claim 1, wherein, The modifier-modified inorganic filler comprises one or more of a modifier-modified oxide solid electrolyte and a modifier-modified metal oxide; The oxide solid electrolyte comprises one or more of lithium lanthanum zirconium oxide, lithium lanthanum zirconium tantalum oxide, lithium vanadium oxide, lithium boron oxide, lithium lanthanum titanium oxide and lithium strontium titanium oxide, and / or the metal oxide comprises one or more of aluminum oxide and silicon dioxide.

7. The polymer electrolyte membrane of claim 1, wherein, The structural formula of the polymer is wherein R is hydroxyl, amino or mercapto, n is 0.6-0.9, m is 0.1-0.4, and n+m=1.

8. The polymer electrolyte membrane of claim 7, wherein, The weight average molecular weight of the polymer is 100000 to 1000000.

9. The polymer electrolyte membrane of claim 1, wherein, The electrolyte salt comprises a lithium salt; The lithium salt comprises one or more of a first lithium salt and a second lithium salt; The first lithium salt comprises one or more of lithium bistrifluoromethanesulfonimide, lithium bisfluorosulfonimide and lithium bis(oxalato)borate, and the second lithium salt comprises one or more of lithium tetrafluoroborate and lithium hexafluorophosphate.

10. The polymer electrolyte membrane of claim 9, wherein, The lithium salt comprises a first lithium salt and a second lithium salt, the mass percentage of the first lithium salt is 99% to 99.9% and the mass percentage of the second lithium salt is 0.1% to 1%, based on the total mass of the lithium salt.

11. The polymer electrolyte membrane according to any one of claims 1 to 9, wherein The Young's modulus of the polymer electrolyte separator is 1 MPa to 30 MPa.

12. A method of producing the polymer electrolyte separator as claimed in any one of claims 1 to 11, wherein, Comprise: An inorganic filler is modified to obtain a modifier-modified inorganic filler; A polymer, an electrolyte salt and the modifier-modified inorganic filler are mixed, and a polymer electrolyte separator is obtained after molding. An inorganic filler is modified to obtain a modifier-modified inorganic filler; A polymer, an electrolyte salt and the modifier-modified inorganic filler are mixed, and a polymer electrolyte separator is obtained after molding.

13. The production method according to claim 12, wherein The mass ratio of the inorganic filler and the modifier is 1:(0.01-0.1); The mass ratio of the inorganic filler modified by the modifier, the electrolyte salt and the polymer is (0.01-0.8):(0.3-0.55):

1.

14. A battery, wherein, The battery comprises a positive electrode sheet and a negative electrode sheet, and a polymer electrolyte separator as claimed in any one of claims 1-11 or prepared by the preparation method as claimed in any one of claims 12-13 is arranged between the positive electrode sheet and the negative electrode sheet.

15. An electrical device, comprising: The power utilization device comprises the battery as claimed in claim 14.

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