Solid electrolyte, and preparation method therefor and use thereof

Abstract

Provided in the present disclosure are a solid electrolyte, a preparation method therefor and a secondary battery. The solid electrolyte comprises an oxide solid electrolyte and a shell layer coating the surface of the oxide solid electrolyte, wherein the shell layer comprises a monomer polymer and an ionic liquid. The monomer polymer is obtained by copolymerizing a first polymeric monomer and a second polymeric monomer, wherein the first polymeric monomer comprises one or more of ethylene glycol monomethyl ether acrylic acid, ethylene glycol monomethyl ether methacrylate, ethylene glycol monoethyl ether methacrylate and ethylene glycol monopropyl ether methacrylate; and the second polymeric monomer comprises a fluoroacrylate. F doping is firstly selected to modify LATP in the present disclosure, thereby significantly improving the ionic conductivity of the LATP, and widening the electrochemical window thereof, which is beneficial to improving the hydrophobicity thereof. The inner structure selected in the present disclosure is an LATP material doped with F, which can form better attraction to a C-containing group in the coating layer and cations of the ionic liquid, thereby improving the coating effect of the outer layer.

Description

Solid-state electrolyte, preparation method and application thereof

[0001] Cross-reference to related applications

[0002] The present application claims priority to the Chinese patent application No. 202410897299.9, filed on July 04, 2024, and entitled "Solid-state electrolyte, preparation method and application thereof", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present disclosure belongs to the technical field of lithium ion batteries, and particularly relates to a solid-state electrolyte, a preparation method and application thereof. BACKGROUND

[0004] At present, with the wide application of new energy technology, the development trend of modern transportation is fully electrified. This makes the requirements of secondary batteries in energy density, safety and cycle life more stringent. However, the existing lithium ion battery system cannot simultaneously meet the requirements of high energy density, high safety, long cycle and safety performance. Therefore, it is urgent to build a revolutionary battery system to solve the inherent contradiction between high energy density and high safety hazard, and meet the more stringent performance requirements of emerging applications. In recent years, the performance of solid-state electrolyte materials has been improved, and solid-state battery technology has made significant progress.

[0005] Solid-state electrolytes mainly include oxide solid-state electrolytes, sulfide solid-state electrolytes, halide solid-state electrolytes, polymer solid-state electrolytes, etc. Among them, sulfides have high ionic conductivity and mechanical properties, and are considered to be a good choice for all-solid-state electrolytes, but their cost and poor stability limit their development in all-solid-state electrolytes; halide solid-state electrolytes also face the problem of chemical instability; polymer solid-state electrolytes have a relatively simple preparation method and good flexibility, but their high crystallinity limits their application due to low ionic conductivity; oxide solid-state electrolytes have good ionic conductivity and air stability, and are considered to be the preferred solid-state electrolyte material for semi-solid-state batteries. Their application fields mainly include positive electrode blending, positive electrode coating, separator coating, negative electrode blending, etc.

[0006] The application of oxide solid-state electrolytes is gradually being promoted, but the poor interfacial compatibility caused by their strong mechanical strength can affect the performance of the applied battery. In addition, the beneficial effects of oxide solid-state electrolytes in semi-solid-state batteries still need to be further researched and explored, and the oxide solid-state electrolytes need to be modified to better perform in semi-solid-state batteries. SUMMARY

[0007] The present disclosure provides a solid-state electrolyte, comprising an oxide solid-state electrolyte and a shell layer coated on the surface of the oxide solid-state electrolyte;

[0008] The shell layer comprises a monomer polymer and an ionic liquid;

[0009] The monomer polymer is obtained by copolymerization of a first polymer monomer and a second polymer monomer, the first polymer monomer comprising one or more of ethylene glycol monomethyl ether acrylic acid, ethylene glycol monomethyl ether methacrylate, ethylene glycol monoethyl ether methacrylate, and ethylene glycol monopropyl ether methacrylate;

[0010] The second polymer monomer comprises a fluorinated acrylate.

[0011] In some embodiments, the oxide solid-state electrolyte is a F-doped lithium aluminum titanium phosphate solid-state electrolyte having a chemical formula as shown in Formula I: Li 1+x-y Al x Ti 2-x P3O 12-y F y Formula I;

[0012] In Formula I, 0.2≤x≤0.6, 0

[0013] In some embodiments, the ionic liquid comprises one or more of [BMIM][TFSI], [OMIM][TFSI], and [EMIM][TFSI].

[0014] In some embodiments, the mass ratio of the oxide solid-state electrolyte to the ionic liquid is 1:(0.01-0.02).

[0015] In some embodiments, the second polymer monomer comprises one or more of pentafluoropropyl acrylate, hexafluorobutyl acrylate, heptafluoropentyl acrylate, perfluorooctyl acrylate, and trifluoroethyl acrylate.

[0016] In some embodiments, the mass ratio of the oxide solid-state electrolyte to the second polymer monomer is 10:(0.01-0.1).

[0017] In some embodiments, the mass ratio of the oxide solid-state electrolyte to the first polymer monomer is 10:(0.01-0.1).

[0018] The present disclosure provides a preparation method of a solid-state electrolyte, comprising the following steps:

[0019] A) mixing oxide solid-state electrolyte powder, ionic liquid, first polymer monomer, second polymer monomer, and photoinitiator in a solvent, drying, and crushing to obtain a mixture powder.

[0020] B) solidifying the mixture under ultraviolet light to obtain a solid-state electrolyte.

[0021] In some embodiments, the oxide solid-state electrolyte powder is prepared by the following steps:

[0022] A lithium source, an aluminum source, a titanium source, a phosphorus source and a fluorine source are ball-milled to obtain a precursor, the precursor is sintered and crushed to obtain an oxide solid-state electrolyte powder.

[0023] The fluorine source includes one or more of lithium fluoride, ammonium fluoride and aluminum fluoride.

[0024] In some embodiments, the sintering temperature of the precursor is 850-1000℃, and the holding time of the precursor sintering is 360-720min.

[0025] In some embodiments, the solidification temperature is 15-40℃, and the solidification time is 2-12 hours.

[0026] The present disclosure provides a lithium ion secondary battery comprising the solid-state electrolyte described above. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only represent the embodiments of the present disclosure by way of example, and the true proportions of the embodiments cannot be directly corresponded to the proportions in the drawings. Meanwhile, the following drawings only show some embodiments of the present disclosure, and therefore should not be regarded as a limitation to the scope.

[0028] FIG. 1 is an SEM image of the solid-state electrolyte prepared in Example 1 of the present disclosure;

[0029] FIG. 2 is an XRD pattern of the solid-state electrolyte prepared in Example 1 of the present disclosure;

[0030] FIG. 3 is a TEM image of the solid-state electrolyte prepared in Example 1 of the present disclosure. DETAILED DESCRIPTION

[0031] The advantages of the embodiments in the specification will be illustrated in the following description of the embodiments, some of which are obvious from the specification or can be obtained by some of the embodiments of the present disclosure.

[0032] The technical solutions of the present disclosure will be further illustrated by some embodiments in combination with the drawings.

[0033] In order to make the objectives, technical solutions and advantages of the present disclosure clearer, the present disclosure will be further described in detail below with reference to the drawings and embodiments. It should be understood that the embodiments described herein are only used to explain the present disclosure and not intended to limit the present disclosure. In addition, the technical features involved in the various embodiments of the present disclosure described below can be combined with each other as long as they do not conflict with each other. Without departing from the principles of the embodiments of the present disclosure, several improvements and refinements can also be made, which are also considered within the protection scope of the embodiments of the present disclosure.

[0034] The present disclosure provides a solid-state electrolyte, comprising an oxide solid-state electrolyte and a shell layer coated on the surface of the oxide solid-state electrolyte;

[0035] The shell layer comprises a monomer polymer and an ionic liquid;

[0036] The monomer polymer is obtained by copolymerization of a first polymer monomer and a second polymer monomer, the first polymer monomer comprising one or more of ethylene glycol monomethyl ether acrylic acid, ethylene glycol monomethyl ether methacrylate, ethylene glycol monoethyl ether methacrylate and ethylene glycol monopropyl ether methacrylate;

[0037] The second polymer monomer comprises a fluorinated acrylic ester.

[0038] In the present disclosure, the oxide solid electrolyte is a F-doped lithium aluminum titanium phosphate solid-state electrolyte, having a chemical formula as shown in Formula I: Li 1+x-y Al x Ti 2-x P3O 12-y F y Formula I;

[0039] In Formula I, 0.2≤x≤0.6, in some embodiments, 0.3≤x≤0.5, such as x being 0.2, 0.3, 0.4, 0.5, 0.6, or a range value with any of the above values as the upper limit or lower limit; 0

[0040] In the present disclosure, the particle size of the oxide solid electrolyte is 100-500 nm. In some embodiments, the particle size of the oxide solid electrolyte is 150-450 nm.

[0041] The present disclosure selects lithium aluminum titanium phosphate (LATP) oxide solid electrolyte material, and uses F-doping modification, which can broaden the Li +The transmission channel, the intrinsic ion conductivity of the LATP is improved, and F doping is conducive to improving the oxidation stability and widening the application voltage of the LATP material, thereby further expanding the application system thereof.

[0042] In the present disclosure, the shell layer comprises a monomer polymer and an ionic liquid; the monomer polymer is obtained by copolymerization of a first polymer monomer and a second polymer monomer under the condition of an initiator, the first polymer monomer comprises one or more of ethylene glycol monomethyl ether acrylic acid, ethylene glycol monomethyl ether methacrylate, ethylene glycol monoethyl ether methacrylate, and ethylene glycol monopropyl ether methacrylate; the mass ratio of the oxide solid electrolyte to the first polymer monomer is 10:(0.01-0.1), in some embodiments, the mass ratio of the oxide solid electrolyte to the first polymer monomer is 10:(0.05-0.08), such as 10:0.01, 10:0.02, 10:0.03, 10:0.04, 10:0.05, 10:0.06, 10:0.07, 10:0.08, 10:0.09, 10:0.1, or a range value with any of the above values as the upper limit or lower limit.

[0043] In the present disclosure, the second polymer monomer comprises a fluorinated acrylate. The second polymer monomer is one or more of pentafluoropropyl acrylate, hexafluorobutyl acrylate, heptafluoropentyl acrylate, perfluorooctyl acrylate, and trifluoroethyl acrylate; the mass ratio of the oxide solid electrolyte to the second polymer monomer is 10:(0.01-0.1), in some embodiments, the mass ratio of the oxide solid electrolyte to the second polymer monomer is 10:(0.05-0.08), such as 10:0.01, 10:0.02, 10:0.03, 10:0.04, 10:0.05, 10:0.06, 10:0.07, 10:0.08, 10:0.09, 10:0.1, or a range value with any of the above values as the upper limit or lower limit.

[0044] In the present disclosure, the ionic liquid is one or more of [BMIM][TFSI], [OMIM][TFSI], and [EMIM][TFSI]; the mass ratio of the oxide solid electrolyte to the ionic liquid is 1:(0.01-0.02).

[0045] In some embodiments, the initiator is a photoinitiator, the photoinitiator is one or more of 2,2-diethoxy-1-phenylhexanone, 1-hydroxycyclohexyl phenyl ketone and 2-hydroxy-2-methyl-1-phenyl-1-propanone; the mass ratio of the oxide solid electrolyte to the initiator is 1000:(0.01-0.1), in some embodiments, the mass ratio of the oxide solid electrolyte to the initiator is 1000:(0.05-0.08), such as 1000:0.01, 1000:0.02, 1000:0.03, 1000:0.04, 1000:0.05, 1000:0.06, 1000:0.07, 1000:0.08, 1000:0.09, 1000:0.1, or a range with any of the above values as the upper or lower limit.

[0046] In the present disclosure, the thickness of the shell layer is 10-50 nm. In some embodiments, the thickness of the shell layer is 20-40 nm.

[0047] The present disclosure also provides a preparation method of the solid-state electrolyte described above, characterized in that it comprises the following steps:

[0048] A) mixing the oxide solid electrolyte powder, the ionic liquid, the first polymer monomer, the second polymer monomer and the photoinitiator in a solvent, drying, crushing to obtain a mixture powder;

[0049] B) curing the mixture powder under ultraviolet light to obtain the solid-state electrolyte.

[0050] In the present disclosure, the oxide solid electrolyte powder is prepared according to the following steps:

[0051] The lithium source, the aluminum source, the titanium source, the phosphorus source and the fluorine source are ball-mixed to obtain a precursor, the precursor is sintered and crushed to obtain the oxide solid electrolyte powder. In some embodiments, the lithium source, the aluminum source, the titanium source, the phosphorus source, the fluorine source and the ball-milling medium are mixed and ball-milled to obtain a precursor slurry, the precursor slurry is dried, sintered, crushed and sieved to obtain the oxide solid electrolyte powder.

[0052] In the present disclosure, the lithium source is one or more of lithium carbonate, lithium hydroxide and lithium dihydrogen phosphate; the aluminum source is one or more of aluminum oxide, aluminum carbonate and aluminum hydroxide; the titanium source is one or more of titanium dioxide and titanium hydroxide, the phosphorus source is one or more of ammonium dihydrogen phosphate, diammonium hydrogen phosphate, titanium pyrophosphate and diaphosphorus pentoxide; the fluorine source is one or more of lithium fluoride, ammonium fluoride and aluminum fluoride. The lithium source, the aluminum source, the titanium source, the phosphorus source and the fluorine source are dosed according to the stoichiometric ratio of the chemical formula shown in formula I, which is a common method in the art, and will not be repeated here in the present disclosure.

[0053] In the present disclosure, the ball milling medium is anhydrous ethanol and / or deionized water, the ball milling time is 3-15 hours, in some embodiments, the ball milling time is 5-10 hours, the ball milling rotation speed is 200-500 r / min, in some embodiments, the ball milling rotation speed is 300-400 r / min.

[0054] In the present disclosure, the drying temperature of the precursor slurry is 80-120°C; the drying time is 12-16 hours.

[0055] In the present disclosure, the sintering temperature is 850-1000°C. In some embodiments, the sintering temperature is 900-950°C. The sintering holding time is 360-720 min. In some embodiments, the sintering holding time is 420-660 min.

[0056] In the present disclosure, after sintering, the precursor is crushed and sieved through a 200-mesh sieve to obtain an oxide solid electrolyte powder.

[0057] After obtaining the oxide solid electrolyte powder, the present disclosure stirs and mixes the oxide solid electrolyte powder and the ionic liquid in a solvent, then adds the first polymer monomer and the second polymer monomer and the initiator to continue stirring, and after uniform stirring, the obtained mixed solution is dried and crushed to obtain a mixture powder.

[0058] In the present disclosure, the types and amounts of the first polymer monomer, the second polymer monomer and the initiator are consistent with those described above, and the present disclosure will not be repeated here.

[0059] In the present disclosure, the solvent is anhydrous ethanol and / or N-methyl pyrrolidone (NMP); the mass ratio of the oxide solid electrolyte powder to the solvent is 1:(2-9). In some embodiments, the mass ratio of the oxide solid electrolyte powder to the solvent is 1:(3-8). In some embodiments, the mass ratio of the oxide solid electrolyte powder to the solvent is 1:(5-6).

[0060] In the present disclosure, the stirring time when mixing the oxide solid electrolyte and the ionic liquid is 10-60 min. In some embodiments, the stirring time when mixing the oxide solid electrolyte and the ionic liquid is 20-50 min. In some embodiments, the stirring time when mixing the oxide solid electrolyte and the ionic liquid is 30-40 min; the continuous stirring time after adding the first polymer monomer, the second polymer monomer and the initiator is 10-180 min, for example, 30-150 min, for example, 50-120 min.

[0061] In the present disclosure, the drying temperature is 60-100℃, for example, 70-90℃, such as 60℃, 70℃, 80℃, 90℃, 100℃, or a range with any of the above values as the upper or lower limit; the drying time is 6-18 hours, for example, 8-15 hours.

[0062] After obtaining the mixture powder, the present disclosure cures the mixture powder under the condition of ultraviolet light irradiation, and then crushes again after curing to obtain a solid electrolyte.

[0063] In the present disclosure, the wavelength of the ultraviolet light is 300-380nm, for example, 320-360nm, such as 330nm, 340nm, 350nm, 360nm, or a range with any of the above values as the upper or lower limit; the curing temperature is 15-40℃, for example, 20-35℃, such as 15℃, 20℃, 25℃, 30℃, 35℃, 40℃, or a range with any of the above values as the upper or lower limit; the curing time is 2-12 hours, for example, 5-10 hours, such as 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, or a range with any of the above values as the upper or lower limit.

[0064] In the present disclosure, the particle size of the crushed particles after curing is 100-500nm, for example, 150-450nm, such as 200nm, 250nm, 300nm, 350nm, 400nm, or a range with any of the above values as the upper or lower limit.

[0065] The present disclosure also provides a lithium ion secondary battery, which comprises a positive electrode, a negative electrode, an electrolyte, and an electrolyte solution, wherein the electrolyte is the solid electrolyte described above.

[0066] In the present disclosure, the solid electrolyte is used as an additive for a lithium ion secondary battery, and the solid electrolyte can be used in a lithium ion secondary battery by means of positive electrode blending, positive electrode coating, separator coating, negative electrode blending, etc. Specifically, in an embodiment of the present disclosure, the solid electrolyte can be used by means of positive electrode blending, and the mass ratio of the solid electrolyte to the positive electrode active material is (0.1-1):(90-98), for example, (0.3-0.8):(92-97), and specifically, in an embodiment of the present disclosure, it can be 0.5:96.3.

[0067] In the present disclosure, the positive electrode active material is lithium cobalt oxide (LCO), ternary material (NCM811, NCM613), 5V spinel (LNMO). The negative electrode and electrolyte can adopt the negative electrode material and electrolyte formula commonly used in the lithium ion secondary battery in the art, such as using lithium metal as the negative electrode and using carbonate solvent as the electrolyte.

[0068] The present disclosure has the following advantages:

[0069] The present disclosure first selects F-doped modified LATP, which significantly improves the ion conductivity of LATP, widens the electrochemical window, and is beneficial to improving the hydrophobicity.

[0070] The internal structure selected by the present disclosure is F-doped LATP material, which can form good attraction to the C-containing groups in the coating layer and the cations of the ionic liquid, improving the coating effect of the outer layer.

[0071] The solid-state electrolyte material prepared by the present disclosure is a modified LATP solid-state electrolyte grain surface coated with an ion-conducting elastomer, the coating layer has excellent mechanical properties, which can effectively alleviate the problems of large stiffness and poor elastic modulus of LATP; the coating layer also has an ionic liquid with excellent ion conductivity, which significantly improves the problem of poor ion conductivity of the grain boundary of the LATP grain; the composite coating layer has a hydrophobic group, which synergistically improves the hydrophobicity of the solid-state electrolyte material.

[0072] The solid-state electrolyte prepared by the present disclosure has improved ion conduction ability in the application process of the battery, which is beneficial to strengthening the charge and discharge capacity of the battery, and the introduction of lower moisture improves the stability of the battery in the cycling process.

[0073] The F ions in the monomer polymer of the outer layer of the solid-state electrolyte selected by the present disclosure can form dynamic ion-dipole interaction with the cations in the ionic liquid, so that the coating layer as a whole has excellent toughness and self-repairing property, significantly improving the interface contact of the solid-state electrolyte with the application end. In the application of positive electrode coating, a good barrier can be formed to inhibit the corrosion of the electrolyte to the core layer material and the positive electrode material, and to prevent the dissolution of excessive metals in the positive electrode material, and its unique self-repairing property improves the long cycle stability of the battery application.

[0074] The outer layer of the solid-state electrolyte prepared by the present disclosure is a monomer polymer, and a certain amount of ionic liquid is introduced therein. The high polymer has good high-temperature resistance, which can enable the solid-state electrolyte to be applied in the field of medium-high temperature batteries. The ionic liquid has extremely low freezing point, which can improve the ion conduction ability of the outer layer high polymer in low temperature environment, so the application of the solid-state electrolyte can comprehensively improve the application temperature range of the battery.

[0075] The following are typical but non-limiting embodiments of the present disclosure:

[0076] Example 1

[0077] 1. Synthesis of LATP material

[0078] Weigh 4.95 g of lithium carbonate, 1.71 g of aluminum oxide, 11.65 g of titanium dioxide, 31.45 g of ammonium dihydrogen phosphate, and 0.25 g of aluminum fluoride into 150 g of anhydrous ethanol for ball milling, the ball milling time is 3 h, and after the ball milling is completed, the precursor slurry is dried at 120℃ for 12 h to obtain a precursor powder. The precursor powder is sintered at a sintering temperature of 900℃ for 720 min with a heating rate of 2℃ / min. After sintering, a F-doped LATP solid-state electrolyte powder is obtained.

[0079] 2. The obtained LATP solid-state electrolyte powder is mechanically broken and sieved through a 200 mesh sieve to obtain a solid-state electrolyte powder. 10 g of the powder is added to 90 g of anhydrous ethanol solvent, followed by the addition of 0.1 g of [BMIM][TFSI] ionic liquid, stirring for 10 min, then adding 0.01 g of ethylene glycol monoethyl ether methacrylate and 0.1 g of hexafluorobutyl acrylate, continuing to stir for 20 min, and then adding 0.001 g of 2,2-diethoxy-1-phenylhexanone photoinitiator, continuing to stir for 40 min. Then the solvent is dried at 60℃ for 18 h, and the dried powder is mechanically broken to obtain a powder. The powder is cured at 20℃ for 8 h under the condition of 300 nm ultraviolet light, and then mechanically broken again to obtain a solid-state electrolyte powder. The inner particles of the solid-state electrolyte are Li 1.3 Al 0.4 Ti 1.6 P3O 11.9 F 0.1 The particle size is 200 nm, and the thickness of the coating layer is 10 nm.

[0080] The SEM image of the solid-state electrolyte prepared in Example 1 is shown in Figure 1, the XRD pattern is shown in Figure 2, and the TEM pattern is shown in Figure 3. As shown in Figures 1 and 2, the prepared solid-state electrolyte has a main phase consistent with the card phase of 35-0754, and no obvious impurity phase. The synthesized solid-state electrolyte particles are irregular spherical, and the primary particle size is about 200 nm. As shown in Figure 3, there is a coating layer with a thickness of about 10 nm on the outer layer of the single irregular inner solid-state electrolyte particle, indicating that the solid-state electrolyte with a coating shell outer layer can be prepared by the scheme of the present embodiment.

[0081] Example 2

[0082] 1. Synthesis of LATP material

[0083] Weigh 3.64 g of lithium carbonate, 1.91 g of aluminum oxide, 10.49 g of titanium dioxide, 32.38 g of ammonium dihydrogen phosphate, 1.57 g of aluminum fluoride into 150 g of anhydrous ethanol for ball milling mixing, the ball milling time is 6 h, after the ball milling is completed, the precursor slurry is oven dried at 80℃ for 16 h to obtain a precursor powder, the precursor powder is sintered, the sintering temperature is 850℃; the holding time is 600 min, and the heating rate is 4℃ / min; after sintering, a F-doped LATP solid-state electrolyte powder is obtained;

[0084] 2, the obtained LATP solid-state electrolyte powder is mechanically broken and then passed through a 200 mesh screen to obtain a solid-state electrolyte powder, 10 g of the powder is added into 70 g of N-methyl pyrrolidone (NMP) solvent, then 0.1 g of [BMIM][TFSI] ionic liquid is added, stirred for 30 min, then 0.01 g of ethylene glycol monomethyl ether methacrylate and 0.1 g of pentafluoropropyl acrylate are added, and the stirring is continued for 60 min, then 0.001 g of 2,2-diethoxy-1-phenylhexanone photoinitiator is added, and the stirring is continued for 120 min. Then the solvent is oven dried at 90℃ for 12 h, and the powder after drying is mechanically broken to obtain a powder, which is cured at 15℃ for 12 h under the condition of 310 nm ultraviolet light, and then mechanically broken again to obtain a solid-state electrolyte powder, the inner particles of the solid-state electrolyte are LiAl 0.6 Ti 1.4 P3O 11.4 F 0.6 , the particle size is 100 nm, and the coating layer thickness is 10 nm.

[0085] Example 3

[0086] 1, synthesis of LATP material

[0087] Weigh 3.64 g of lithium carbonate, 1.91 g of aluminum oxide, 10.49 g of titanium dioxide, 32.38 g of ammonium dihydrogen phosphate, 1.57 g of aluminum fluoride into 150 g of anhydrous ethanol for ball milling mixing, the ball milling time is 6 h, after the ball milling is completed, the precursor slurry is oven dried at 80℃ for 16 h to obtain a precursor powder, the precursor powder is sintered, the sintering temperature is 850℃; the holding time is 600 min, and the heating rate is 4℃ / min; after sintering, a F-doped LATP solid-state electrolyte powder is obtained;

[0088] 2, the obtained LATP solid electrolyte powder is mechanically broken and sieved through a 200 mesh screen to obtain a solid electrolyte powder, 10 g of the powder is added to 50 g of anhydrous ethanol solvent, then 0.15 g of [OMIM][TFSI] ionic liquid is added, stirred for 20 min, then 0.05 g of ethylene glycol monomethyl ether acrylate and 0.05 g of heptafluoropentyl acrylate are added, and the stirring is continued for 30 min, then 0.005 g of 1-hydroxycyclohexyl phenyl ketone photoinitiator is added, and the stirring is continued for 180 min. Then the solvent is dried at 100°C for 10h, the dried powder is mechanically broken to obtain a powder, the powder is cured at 40°C for 2h under the condition of 320nm ultraviolet light, and after the curing treatment, the powder is mechanically broken again to obtain a solid electrolyte powder, and the inner layer particles of the solid electrolyte are Li 0.9 Al 0.2 Ti 1.8 P3O 11.7 F 0.3 , the particle size is 500 nm, and the thickness of the coating layer is 50 nm.

[0089] Example 4

[0090] 1, synthesis of LATP material

[0091] 2.53 g of lithium carbonate, 0.95 g of aluminum oxide, 12.67 g of titanium dioxide, 30.25 g of ammonium dihydrogen phosphate, and 1.57 g of aluminum fluoride are weighed and added to 150 g of deionized water for ball milling, the ball milling time is 12 h, and after the ball milling is completed, the precursor slurry is dried at 120°C for 12 h to obtain a precursor powder, the precursor powder is sintered, the sintering temperature is 1000°C, the holding time is 360 min, and the heating rate is 5°C / min; after sintering, a F-doped LATP solid electrolyte powder is obtained;

[0092] 2, the obtained LATP solid electrolyte powder is mechanically broken and sieved through a 200 mesh screen to obtain a solid electrolyte powder, 10 g of the powder is added to 50 g of anhydrous ethanol solvent, then 0.15 g of [OMIM][TFSI] ionic liquid is added, stirred for 20 min, then 0.05 g of ethylene glycol monomethyl ether acrylate and 0.05 g of heptafluoropentyl acrylate are added, and the stirring is continued for 30 min, then 0.005 g of 1-hydroxycyclohexyl phenyl ketone photoinitiator is added, and the stirring is continued for 180 min. Then the solvent is dried at 100°C for 10h, the dried powder is mechanically broken to obtain a powder, the powder is cured at 40°C for 2h under the condition of 320nm ultraviolet light, and after the curing treatment, the powder is mechanically broken again to obtain a solid electrolyte powder, and the inner layer particles of the solid electrolyte are Li 0.7 Al 0.3 Ti 1.7P3O 11.4 F 0.6 , particle size 300 nm, coating layer thickness 20 nm.

[0093] Example 5

[0094] 1. Synthesis of LATP material

[0095] Weigh 1.59 g of lithium hydroxide, 4.88 g of aluminum hydroxide, 17.13 g of titanium hydroxide, 22.48 g of phosphorus pentoxide, 3.91 g of ammonium fluoride into 150 g of anhydrous ethanol for ball milling, the ball milling time is 6 h, after the ball milling is completed, the precursor slurry is oven dried at 80℃ for 16 h to obtain the precursor powder, and the precursor powder is sintered, the sintering temperature is 850℃; the holding time is 600 min, and the heating rate is 4℃ / min; after sintering, the F-doped LATP solid-state electrolyte powder is obtained;

[0096] 2. The obtained LATP solid-state electrolyte powder is mechanically broken and then sieved through a 200 mesh sieve to obtain the solid-state electrolyte powder, 10 g of the powder is added into 90 g of anhydrous ethanol solvent, then 0.1 g of [BMIM][TFSI] ionic liquid is added, stirred for 10 min, then 0.01 g of ethylene glycol monoethyl ether methacrylate and 0.1 g of trifluoroethyl acrylate are added, and continue to stir for 20 min, then 0.001 g of 2,2-diethoxy-1-phenylhexanone photoinitiator is added, and continue to stir for 60 min. Then the solvent is oven dried at 70℃ for 16 h, and the powder after drying is mechanically broken to obtain the powder, which is cured at 20℃ for 10 h under the condition of 340 nm ultraviolet light, and then mechanically broken again to obtain the solid-state electrolyte powder. The inner particles of the solid-state electrolyte are Li 0.6 Al 0.6 Ti 1.4 P3O 11 F, particle size 400 nm, coating layer thickness 40 nm.

[0097] Example 6

[0098] 1. Synthesis of LATP material

[0099] Weigh 3.30 g of lithium hydroxide, 5.05 g of aluminum hydroxide, 17.76 g of titanium hydroxide, 23.31 g of phosphorus pentoxide, 0.57 g of lithium fluoride into 150 g of deionized water for ball milling, the ball milling time is 9 h, after the ball milling is completed, the precursor slurry is oven dried at 120℃ for 16 h to obtain the precursor powder, and the precursor powder is sintered, the sintering temperature is 950℃; the holding time is 480 min, and the heating rate is 6℃ / min; after sintering, the F-doped LATP solid-state electrolyte powder is obtained;

[0100] 2, the obtained LATP solid electrolyte powder is mechanically broken and sieved through a 200 mesh screen to obtain a solid electrolyte powder, 10 g of the powder is added to 60 g of N-methylpyrrolidone (NMP) solvent, then 0.15 g of [OMIM][TFSI] ionic liquid is added, stirred for 30 min, then 0.05 g of ethylene glycol monomethyl ether methacrylate and 0.05 g of pentafluoropropyl acrylate are added, and the stirring is continued for 60 min, then 0.005 g of 1-hydroxycyclohexyl phenyl ketone initiator is added, and the stirring is continued for 120 min. Then the solvent is dried at 60°C for 15h, the dried powder is mechanically broken to obtain a powder, the powder is cured at 30°C for 10h under the condition of 350nm ultraviolet light, and after the curing treatment, the powder is mechanically broken again to obtain a solid electrolyte powder, the inner layer particles of the solid electrolyte are Li 1.4 Al 0.6 Ti 1.4 P3O 11.8 F 0.2 , the particle size is 200 nm, and the thickness of the coating layer is 15 nm.

[0101] Example 7

[0102] 1, synthesis of LATP material

[0103] 1.07 g of lithium hydroxide, 4.10 g of aluminum hydroxide, 18.55 g of titanium hydroxide, 22.71 g of diaphosphorus pentoxide, and 3.56 g of lithium fluoride are weighed and added to 150 g of deionized water for ball milling, the ball milling time is 12 h, and after the ball milling is completed, the precursor slurry is dried at 120°C for 12 h to obtain a precursor powder, the precursor powder is sintered, the sintering temperature is 1000°C, the holding time is 360 min, and the heating rate is 5°C / min; after the sintering is completed, a F-doped LATP solid electrolyte powder is obtained;

[0104] 2, the obtained LATP solid electrolyte powder is mechanically broken and sieved through a 200 mesh screen to obtain a solid electrolyte powder, 10 g of the powder is added to 60 g of N-methylpyrrolidone (NMP) solvent, then 0.15 g of [OMIM][TFSI] ionic liquid is added, stirred for 30 min, then 0.05 g of ethylene glycol monomethyl ether methacrylate and 0.05 g of pentafluoropropyl acrylate are added, and the stirring is continued for 60 min, then 0.005 g of 1-hydroxycyclohexyl phenyl ketone initiator is added, and the stirring is continued for 120 min. Then the solvent is dried at 60°C for 15h, the dried powder is mechanically broken to obtain a powder, the powder is cured at 30°C for 10h under the condition of 350nm ultraviolet light, and after the curing treatment, the powder is mechanically broken again to obtain a solid electrolyte powder, the inner layer particles of the solid electrolyte are Li 0.4 Al 0.5Ti 1.5 P3O 11.1 F 0.9 , particle size 350 nm, coating layer thickness 30 nm.

[0105] Example 8

[0106] 1. Synthesis of LATP material

[0107] 1.33 g of alumina, 3.13 g of titanium dioxide, 40.50 g of titanium pyrophosphate, 2.03 g of lithium fluoride were weighed and ball-milled in 150 g of anhydrous ethanol, the ball-milling time was 6 h, after the ball-milling was completed, the precursor slurry was oven-dried at 80 °C for 16 h to obtain a precursor powder, the precursor powder was sintered, the sintering temperature was 850 °C; the holding time was 600 min, and the heating rate was 4 °C / min; after sintering, a F-doped LATP solid-state electrolyte powder was obtained;

[0108] 2. The obtained LATP solid-state electrolyte powder was mechanically broken and sieved through a 200 mesh sieve to obtain a solid-state electrolyte powder, 10 g of the powder was added to 90 g of N-methyl pyrrolidone (NMP) solvent, then 0.1 g of [BMIM][TFSI] ionic liquid was added, stirred for 10 min, then 0.01 g of ethylene glycol monoethyl ether methacrylate and 0.1 g of perfluoro octyl acrylate were added, and stirred for 20 min, then 0.001 g of 2,2-diethoxy-1-phenyl hexanone photoinitiator was added, and the stirring was continued for 120 min. Then the solvent was oven-dried at 90 °C for 12 h, the powder after drying was mechanically broken to obtain a powder, the powder was cured at 40 °C for 8 h under the condition of 370 nm ultraviolet light, and after the curing treatment, the powder was mechanically broken again to obtain a solid-state electrolyte powder, the inner particles of the solid-state electrolyte were Li 0.6 Al 0.2 Ti 1.8 P3O 11.4 F 0.6 , particle size 100 nm, coating layer thickness 15 nm.

[0109] Example 9

[0110] 1. Synthesis of LATP material

[0111] 4.64 g of lithium carbonate, 1.851 g of alumina, 1.93 g of titanium dioxide, 40.27 g of titanium pyrophosphate, and 1.26 g of lithium fluoride were weighed and ball-milled in 150 g of deionized water, the ball-milling time was 9 h, after the ball-milling was completed, the precursor slurry was oven-dried at 120 °C for 16 h to obtain a precursor powder, the precursor powder was sintered, the sintering temperature was 950 °C; the holding time was 480 min, and the heating rate was 6 °C / min; after sintering, a F-doped LATP solid-state electrolyte powder was obtained;

[0112] 2, the obtained LATP solid electrolyte powder is mechanically broken and sieved through a 200 mesh sieve to obtain a solid electrolyte powder, 10 g of the powder is added to 60 g of anhydrous ethanol solvent, then 0.15 g of [OMIM][TFSI] ionic liquid is added, stirred for 30 min, then 0.05 g of ethylene glycol monomethyl ether methacrylate and 0.05 g of pentafluoropropyl acrylate are added, and the stirring is continued for 30 min, then 0.005 g of 1-hydroxycyclohexyl phenyl ketone photoinitiator is added, and the stirring is continued for 160 min. Then the solvent is dried at 80°C for 18h, the dried powder is mechanically broken to obtain a powder, the powder is cured at 35°C for 6h under the condition of 380nm ultraviolet light, and after the curing treatment, the powder is mechanically broken again to obtain a solid electrolyte powder, and the inner layer particles of the solid electrolyte are Li 0.9 Al 0.3 Ti 1.7 P3O 11.6 F 0.4 , the particle size is 250 nm, and the thickness of the coating layer is 20 nm.

[0113] Example 10

[0114] 1, synthesis of LATP material

[0115] 4.95 g of lithium carbonate, 1.71 g of aluminum oxide, 11.65 g of titanium dioxide, 31.45 g of ammonium dihydrogen phosphate, and 0.25 g of ammonium fluoride are weighed and added to 150 g of deionized water for ball milling, the ball milling time is 12 h, and after the ball milling is completed, the precursor slurry is dried at 120°C for 12 h to obtain a precursor powder, the precursor powder is sintered, the sintering temperature is 1000°C, the holding time is 360 min, and the heating rate is 5°C / min; after sintering, a F-doped LATP solid electrolyte powder is obtained;

[0116] 2, the obtained LATP solid electrolyte powder is mechanically broken and sieved through a 200 mesh sieve to obtain a solid electrolyte powder, 10 g of the powder is added to 60 g of anhydrous ethanol solvent, then 0.15 g of [OMIM][TFSI] ionic liquid is added, stirred for 30 min, then 0.05 g of ethylene glycol monomethyl ether methacrylate and 0.05 g of pentafluoropropyl acrylate are added, and the stirring is continued for 30 min, then 0.005 g of 1-hydroxycyclohexyl phenyl ketone photoinitiator is added, and the stirring is continued for 160 min. Then the solvent is dried at 80°C for 18h, the dried powder is mechanically broken to obtain a powder, the powder is cured at 35°C for 6h under the condition of 380nm ultraviolet light, and after the curing treatment, the powder is mechanically broken again to obtain a solid electrolyte powder, and the inner layer particles of the solid electrolyte are Li 1.3 Al0.4 Ti 1.6 P3O 11.9 F 0.1 , particle size is 500 nm, and the coating layer thickness is 45 nm.

[0117] Comparative Example 1

[0118] The conventional LATP material without F doping is used

[0119] 1. Synthesis of LATP material

[0120] 4.95 g of lithium carbonate, 1.71 g of aluminum oxide, 11.65 g of titanium dioxide, and 31.45 g of ammonium dihydrogen phosphate are weighed and added to 150 g of anhydrous ethanol for ball milling mixing. The ball milling time is 3 h. After the ball milling is completed, the precursor slurry is oven dried at 120°C for 12 h to obtain a precursor powder. The precursor powder is sintered at a sintering temperature of 900°C for a holding time of 720 min, and the heating rate is 2°C / min. After sintering, a LATP solid-state electrolyte powder is obtained.

[0121] 2. The obtained LATP solid-state electrolyte powder is mechanically broken and sieved through a 200 mesh sieve to obtain a solid-state electrolyte powder. 10 g of the powder is added to 90 g of anhydrous ethanol solvent, followed by the addition of 0.1 g of [BMIM][TFSI] ionic liquid. After stirring for 10 min, 0.01 g of ethylene glycol monoethyl ether methacrylate and 0.1 g of hexafluorobutyl acrylate are added, and the stirring is continued for 20 min. Then, 0.001 g of 2,2-diethoxy-1-phenylhexanone photoinitiator is added, and the stirring is continued for 40 min. Subsequently, the solvent is oven dried at 60°C for 18 h. The oven-dried powder is mechanically broken to obtain a powder. The powder is cured at 20°C for 8 h under the condition of 300 nm ultraviolet light. After the curing treatment, the powder is again mechanically broken to obtain a solid-state electrolyte powder. The inner layer particles of the solid-state electrolyte are Li 1.4 Al 0.4 Ti 1.6 P3O 12 . The particle size is 200 nm, and the coating layer thickness is 10 nm.

[0122] Comparative Example 2

[0123] The LATP material directly doped with F is used without organic material compounding and coating

[0124] 1. Synthesis of LATP material

[0125] Weigh 4.95g of lithium carbonate, 1.71g of aluminum oxide, 11.65g of titanium dioxide, 31.45g of ammonium dihydrogen phosphate, 0.25g of aluminum fluoride into 150g of anhydrous ethanol for ball milling mixing, the ball milling time is 3h, after the ball milling is completed, the precursor slurry is dried at 120℃ for 12h to obtain the precursor powder, the precursor powder is sintered, the sintering temperature is 900℃; the holding time is 720min, the heating rate is 2℃ / min; after sintering, the F-doped LATP solid-state electrolyte powder Li 1.3 Al 0.4 Ti 1.6 P3O 11.9 F 0.1 ;

[0126] Comparative example 3

[0127] Only monomer 1 is selected for composite coating

[0128] 1. Synthesis of LATP material

[0129] Weigh 4.95g of lithium carbonate, 1.71g of aluminum oxide, 11.65g of titanium dioxide, 31.45g of ammonium dihydrogen phosphate, 0.25g of aluminum fluoride into 150g of anhydrous ethanol for ball milling mixing, the ball milling time is 3h, after the ball milling is completed, the precursor slurry is dried at 120℃ for 12h to obtain the precursor powder, the precursor powder is sintered, the sintering temperature is 900℃; the holding time is 720min, the heating rate is 2℃ / min; after sintering, the F-doped LATP solid-state electrolyte powder Li

[0130] 2. The obtained LATP solid-state electrolyte powder is mechanically broken and sieved through a 200 mesh screen to obtain a solid-state electrolyte powder, 10g of the powder is added to 90g of anhydrous ethanol solvent, then 0.1g of [BMIM][TFSI] ionic liquid is added, stirred for 10min, then 0.11g of ethylene glycol monoethyl ether methacrylate is added, and stirred for 20min, then 0.001g of 2,2-diethoxy-1-phenylhexanone photoinitiator is added, and stirred for 40min. Then the solvent is dried at 60℃ for 18h, and the dried powder is mechanically broken to obtain a powder, which is cured at 20℃ for 8h under the condition of 300nm ultraviolet light, and then mechanically broken again to obtain a solid-state electrolyte powder, the inner particles of the solid-state electrolyte are Li 1.3 Al 0.4 Ti 1.6 (PO 3.966 )3F 0.1 , the particle size is 200nm, and the coating layer thickness is 10nm.

[0131] Comparative example 4

[0132] Only monomer 2 is selected for composite coating

[0133] 1. Synthesis of LATP material

[0134] Weigh 4.95g of lithium carbonate, 1.71g of aluminum oxide, 11.65g of titanium dioxide, 31.45g of ammonium dihydrogen phosphate, 0.25g of aluminum fluoride into 150g of anhydrous ethanol for ball milling mixing, the ball milling time is 3h, after the ball milling is completed, the precursor slurry is oven dried at 120℃ for 12h to obtain the precursor powder, the precursor powder is sintered, the sintering temperature is 900℃; the holding time is 720min, the heating rate is 2℃ / min; after sintering, the F-doped LATP solid-state electrolyte powder is obtained;

[0135] 2. The obtained LATP solid-state electrolyte powder is mechanically broken and sieved through a 200 mesh screen to obtain a solid-state electrolyte powder, 10g of the powder is added into 90g of anhydrous ethanol solvent, then 0.1g of [BMIM][TFSI] ionic liquid is added, stirred for 10min, then 0.11g of hexafluorobutyl acrylate is added and stirred for 20min, then 0.001g of 2,2-diethoxy-1-phenylhexanone photoinitiator is added, and the stirring is continued for 40min. Then the solvent is oven dried at 60℃ for 18h, and the dried powder is mechanically broken to obtain a powder, which is cured at 20℃ for 8h under the condition of 300nm ultraviolet light, and then mechanically broken again to obtain a solid-state electrolyte powder. The inner particles of the solid-state electrolyte are Li 1.3 Al 0.4 Ti 1.6 (PO 3.966 )3F 0.1 , the particle size is 200nm, and the coating layer thickness is 10nm.

[0136] Comparative example 5

[0137] Selecting common polytetrafluoroethylene solid-state electrolyte for compounding with F-containing LATP

[0138] 1. Synthesis of LATP material

[0139] Weigh 4.95g of lithium carbonate, 1.71g of aluminum oxide, 11.65g of titanium dioxide, 31.45g of ammonium dihydrogen phosphate, 0.25g of aluminum fluoride into 150g of anhydrous ethanol for ball milling mixing, the ball milling time is 3h, after the ball milling is completed, the precursor slurry is oven dried at 120℃ for 12h to obtain the precursor powder, the precursor powder is sintered, the sintering temperature is 900℃; the holding time is 720min, the heating rate is 2℃ / min; after sintering, the F-doped LATP solid-state electrolyte powder is obtained;

[0140] 2, the obtained LATP solid electrolyte powder is mechanically broken and passed through a 200 mesh screen to obtain a solid electrolyte powder, 10 g of the powder is added to 90 g of anhydrous ethanol solvent, then 0.1 g of [BMIM][TFSI] ionic liquid is added, stirred for 10 min, then 0.01 g of ethylene glycol monoethyl ether methacrylate and 0.1 g of n-butyl acrylate are added, and the mixture is stirred for 20 min. 0.001 g of 2,2-diethoxy-1-phenyl hexanone photoinitiator is added, and the mixture is continuously stirred for 40 min. Then the solvent is dried at 60°C for 18h, the dried powder is mechanically broken to obtain a powder, the powder is cured at 20°C for 8h under the condition of 300nm ultraviolet light, and then mechanically broken again to obtain a solid electrolyte powder. The inner layer particles of the solid electrolyte are Li 1.3 Al 0.4 Ti 1.6 (PO 3.966 )3F 0.1 The particle size is 200 nm, and the coating layer thickness is 10 nm.

[0141] Comparative example 6

[0142] Selecting a monomer without F group and F-containing LATP for compounding

[0143] 1. Synthesis of LATP material

[0144] 4.95 g of lithium carbonate, 1.71 g of aluminum oxide, 11.65 g of titanium dioxide, 31.45 g of ammonium dihydrogen phosphate, and 0.25 g of aluminum fluoride are weighed and added to 150 g of anhydrous ethanol for ball milling. The ball milling time is 3h. After ball milling, the precursor slurry is dried at 120°C for 12h to obtain a precursor powder. The precursor powder is sintered at a sintering temperature of 900°C for 720 min with a heating rate of 2°C / min. After sintering, a F-doped LATP solid electrolyte powder is obtained.

[0145] 2, the obtained LATP solid electrolyte powder is mechanically broken and passed through a 200 mesh screen to obtain a solid electrolyte powder, 10 g of the powder is added to 90 g of anhydrous ethanol solvent, then 0.1 g of [BMIM][TFSI] ionic liquid is added, stirred for 10 min, then 0.01 g of ethylene glycol monoethyl ether methacrylate and 0.1 g of n-butyl acrylate are added, and the mixture is stirred for 20 min. 0.001 g of 2,2-diethoxy-1-phenyl hexanone photoinitiator is added, and the mixture is continuously stirred for 40 min. Then the solvent is dried at 60°C for 18h, the dried powder is mechanically broken to obtain a powder, the powder is cured at 20°C for 8h under the condition of 300nm ultraviolet light, and then mechanically broken again to obtain a solid electrolyte powder. The inner layer particles of the solid electrolyte are Li 1.3 Al0.4 Ti 1.6 P3O 11.9 F 0.1 The particle size is 200 nm, and the coating layer thickness is 10 nm.

[0146] Comparative Example 7

[0147] The blank positive electrode sample was selected to prepare a 2032 button cell according to the following steps, without adding a solid electrolyte material.

[0148] The solid electrolyte powder prepared in the above examples and comparative examples was used for positive electrode blending. In this scheme, LCO was used as the positive electrode active material. During the positive electrode homogenization process, the proportion of the added substances was LCO: solid electrolyte: SP: PVDF = 96.3%: 0.5%: 2%: 2.2%.

[0149] A 2032 button cell was assembled using the above positive electrode sheet. In an argon glove box with a water and oxygen content of less than 0.01 ppm, a 2032 button cell was prepared using the prepared solid electrolyte blended LCO as the positive electrode, a lithium metal sheet as the negative electrode, 1M LiPF6 dissolved in a mixed solution of ethylene carbonate (EC) / dimethyl carbonate (DMC) / diethyl carbonate (EMC) (volume ratio 1:1:1) as the electrolyte, and polypropylene as the separator. The battery was subjected to charge and discharge tests at a voltage of 3-4.45V. The results are shown in Table 1.

[0150] Table 1 Electrochemical performance data of button cells assembled by positive electrode blending of examples and comparative examples

[0151] From the comparison of the electrochemical performance of the button cells of the examples and comparative examples in Table 1, it can be seen that the solid electrolyte prepared in this scheme can better fill the grain boundaries, achieve excellent grain boundary ion conduction, improve the charge and discharge capacity of the battery, and thus improve the rate performance. In addition, the excellent composite elastomer coating layer makes the interface contact good, which can significantly improve the cycle stability of the battery. The monomer 2 selected in this scheme contains a F group, which can synergistically improve the application voltage of the solid electrolyte, and thus effectively improve the performance of the battery at high voltage.

[0152] At the same time, the unique monomer selection and ionic liquid in this scheme enable the prepared solid electrolyte to have self-repairing property and high and low temperature stability, which significantly promotes the conduction of lithium ions at low temperature in the application of blending positive electrodes. Compared with the experimental design of the comparative examples, the low temperature charge and discharge capacity of the battery is further improved, and the charge and discharge cycle stability of the battery at 45°C can be ensured, and the high and low temperature performance of the battery is improved. Industrial applicability

[0153] In summary, the present disclosure provides a solid-state electrolyte, a preparation method and application thereof. The solid-state electrolyte in the present disclosure selects F-doped modified LATP, which significantly improves the ion conductivity of LATP, widens the electrochemical window, is beneficial to improving the hydrophobicity, can form better attraction to the C-containing groups and cations of ionic liquid in the coating layer, and improves the coating effect of the outer layer. The solid-state electrolyte has good hydrophobicity and high ion conductivity, can improve the cycle stability and rate capability of the battery, and improves the safety.

Claims

1. A solid-state electrolyte comprising an oxide solid-state electrolyte and a shell layer coated on the surface of the oxide solid-state electrolyte; the shell layer comprises a monomer polymer and an ionic liquid; the monomer polymer is obtained by copolymerization of a first polymer monomer and a second polymer monomer, the first polymer monomer comprises one or more of ethylene glycol monomethyl ether acrylic acid, ethylene glycol monomethyl ether methacrylate, ethylene glycol monoethyl ether methacrylate and ethylene glycol monopropyl ether methacrylate; the second polymer monomer comprises a fluorinated acrylate.

2. The solid-state electrolyte of claim 1, wherein, The oxide solid electrolyte is a F-doped lithium titanium aluminum phosphate solid electrolyte having a chemical formula shown in Formula I: Li 1+x-y Al x Ti 2-x P3O 12-y F y Formula I; In formula I, 0.2≤x≤0.6, 0 3. The solid-state electrolyte of claim 1 or 2, wherein, the ionic liquid comprises one or more of [BMIM][TFSI], [OMIM][TFSI] and [EMIM][TFSI].

4. The solid-state electrolyte according to any one of claims 1 to 3, characterized in that, The mass ratio of the oxide solid electrolyte to the ionic liquid is 1:(0.01-0.02).

5. The solid-state electrolyte according to any one of claims 1 to 4, characterized in that, The second polymer monomer comprises one or more of pentafluoropropyl acrylate, hexafluorobutyl acrylate, heptafluoropentyl acrylate, perfluorooctyl acrylate and trifluoroethyl acrylate.

6. The solid-state electrolyte according to any one of claims 1 to 5, characterized in that, The mass ratio of the oxide solid electrolyte to the second polymer monomer is 10:(0.01-0.1).

7. The solid-state electrolyte according to any one of claims 1 to 6, characterized in that, The mass ratio of the oxide solid electrolyte to the first polymer monomer is 10:(0.01-0.1).

8. The method of producing a solid-state electrolyte according to any one of claims 1 to 7, characterized by, comprising the following steps: A) mixing an oxide solid-state electrolyte powder, an ionic liquid, a first polymer monomer, a second polymer monomer and a photoinitiator in a solvent, drying, crushing to obtain a mixture powder; B) curing the mixture powder under ultraviolet light to obtain a solid-state electrolyte.

9. The preparation method according to claim 8, characterized in that, The oxide solid-state electrolyte powder is prepared according to the following steps: ball-milling a lithium source, an aluminum source, a titanium source, a phosphorus source and a fluorine source to obtain a precursor, sintering the precursor, crushing to obtain an oxide solid-state electrolyte powder; The fluorine source comprises one or more of lithium fluoride, ammonium fluoride and aluminum fluoride.

10. The method of claim 9, wherein, The sintering temperature of the precursor is 850-1000°C, and the holding time of the precursor sintering is 360-720 min.

11. The production method according to any one of claims 8 to 10, characterized by, The curing temperature is 15-40°C, and the curing time is 2-12 hours.

12. A lithium-ion secondary battery, characterized by comprising: The solid-state electrolyte prepared by the preparation method of any one of claims 8-11.

Images