Solid-state electrolyte as well as preparation method therefor and use thereof

Abstract

A solid-state electrolyte as well as a preparation method therefor and the use thereof. The solid-state electrolyte comprises aluminosilicate and an oxide electrolyte body, the solid-state electrolyte is of a porous Na-Y type cage-shaped structure, and the solid-state electrolyte has excellent ion conduction capability.

Description

Solid-state electrolyte and preparation method and application thereof TECHNICAL FIELD

[0001] The embodiments of the present application relate to a solid-state electrolyte and a preparation method and application thereof, and belong to the technical field of secondary batteries. BACKGROUND

[0002] Developing high-performance secondary batteries has great strategic significance for environmental protection, energy efficient use and many other aspects. The secondary battery system usually includes a liquid electrolyte, however, the liquid electrolyte is prone to leakage, battery short circuit and thus causes dangerous accidents such as battery combustion and explosion. Compared with the liquid electrolyte, the use of solid-state electrolyte can inhibit the generation of negative electrode dendrites to some extent, thereby avoiding battery short circuit and reducing the proportion of combustible substances in the battery, so the battery using the solid-state electrolyte has higher safety compared with the battery using the liquid electrolyte. However, the ion conduction ability of the existing solid-state electrolyte still needs to be further improved.

[0003] SUMMARY

[0004] The present application provides a solid-state electrolyte, which has excellent ion conduction ability.

[0005] The present application provides a preparation method of a solid-state electrolyte, which is used for preparing the above-mentioned solid-state electrolyte, and the preparation method is simple in operation and suitable for wide application.

[0006] The present application provides a separator, which comprises the above-mentioned solid-state electrolyte, and when applied to a battery, the separator can improve the lithium ion transmission performance of the battery and can have excellent interface compatibility with the positive and negative electrodes.

[0007] The present application provides a battery, which comprises any one of the above-mentioned solid-state electrolyte, the solid-state electrolyte prepared by the above-mentioned preparation method and the above-mentioned separator, and the battery has excellent electrochemical performance.

[0008] The present application provides a solid-state electrolyte, wherein the solid-state electrolyte comprises a silicoaluminate and an oxide electrolyte body.

[0009] The solid-state electrolyte is a porous Na-Y type cage structure.

[0010] The solid-state electrolyte as described above, wherein in the solid-state electrolyte, the mass ratio of the silicoaluminate to the oxide electrolyte body is (2-5): 1.

[0011] The solid-state electrolyte as described above, wherein in the solid-state electrolyte, the molar ratio of silicon element to aluminum element is (2-3): 1.

[0012] The solid electrolyte as described above, wherein the solid electrolyte has a chain alkyl group in the pores thereof.

[0013] The solid electrolyte as described above, wherein the solid electrolyte satisfies one of the following:

[0014] a) the average particle size of the solid electrolyte is 0.2-2 μm;

[0015] b) the average pore size of the solid electrolyte is 1-100 nm;

[0016] c) the specific surface area of the solid electrolyte is ≥300 m 2 / g;

[0017] d) the pore volume ratio of the solid electrolyte is 20-40%.

[0018] The application provides a preparation method of the solid electrolyte as described above, wherein the preparation method comprises:

[0019] mixing the alkyl surfactant with the oxide electrolyte body to obtain a solid electrolyte template micelle coated with the alkyl surfactant;

[0020] mixing the Y-type precursor with the solid electrolyte template micelle to obtain a directing micelle, adding a silicon source, an aluminum source and a sodium source to the directing micelle to obtain a reaction solution;

[0021] sequentially performing a hydrothermal crystallization reaction and a calcination treatment on the reaction solution to obtain the solid electrolyte.

[0022] The preparation method as described above, wherein the first mixing treatment comprises: mixing the alkyl surfactant with water, adjusting the pH to 4.5-6.5, performing ultrasonic dispersion, and then adding the oxide electrolyte body to obtain the solid electrolyte template micelle.

[0023] The preparation method as described above, wherein the first mixing treatment further comprises: adjusting the pH by using concentrated hydrochloric acid.

[0024] The preparation method as described above, wherein the preparation method comprises one of the following:

[0025] a) in the hydrothermal crystallization reaction, the temperature is 110-120℃ and the time is 10-14h;

[0026] b) in the calcination treatment, the temperature is 260-300℃ and the time is 4-8h.

[0027] The application provides a separator, which comprises a separator substrate and a solid electrolyte layer arranged on at least one surface of the separator substrate and / or in at least part of the pores of the separator substrate,

[0028] The solid-state electrolyte layer comprises the solid-state electrolyte as described above; or, the solid-state electrolyte layer comprises the solid-state electrolyte prepared by the preparation method as described above.

[0029] The separator as described above, wherein the separator satisfies one of the following:

[0030] a) the thickness of the separator substrate is 2-20 μm;

[0031] b) the thickness of the solid-state electrolyte layer is 0.5-5 μm;

[0032] c) the bulk density of the solid-state electrolyte layer is 1-1.2 g / cm 3 .

[0033] The separator as described above, wherein,

[0034] when the ratio of the thickness of the solid-state electrolyte layer to the thickness of the separator is ≤20%, the separator satisfies one of the following:

[0035] a) the thermal shrinkage rate of the separator at 150℃ is ≤3%;

[0036] b) the air permeability value increment of the separator is 10-30 s / 100cc;

[0037] c) the electrochemical stability window of the separator is ≥5.1 V.

[0038] The separator as described above, wherein the separator further comprises an electrolyte filled in the pores of the solid-state electrolyte layer.

[0039] The application provides a battery, wherein the battery comprises the solid-state electrolyte as described above; or,

[0040] the battery comprises the solid-state electrolyte prepared by the preparation method as described above; or,

[0041] the battery comprises the separator as described above.

[0042] The solid-state electrolyte of the application comprises a silicoaluminate and an oxide electrolyte body, and the solid-state electrolyte is a porous Na-Y type cage structure. The Lewis acid sites of the silicoaluminate and the oxide electrolyte body are matched with each other, which enhances the adsorption between the silicoaluminate and the oxide electrolyte body, thereby improving the structural stability of the solid-state electrolyte. Since the solid-state electrolyte is a porous Na-Y type cage structure, it not only provides a channel for the transmission of metal ions and improves the transmission performance of metal ions, but also stores metal ions, thereby improving the interface performance between the solid-state electrolyte and the positive and negative electrodes.

[0043] The preparation method of the solid-state electrolyte of the present application can prepare the above-mentioned solid-state electrolyte with excellent lithium ion transmission performance and excellent interface compatibility with the positive and negative electrodes.

[0044] The separator of the present application includes the above-mentioned solid-state electrolyte, which can improve the ion transmission performance of the battery and has excellent interface compatibility with the positive and negative electrodes when applied to the battery, thereby improving the electrochemical performance of the battery.

[0045] The battery of the present application includes any one of the above-mentioned solid-state electrolyte, the solid-state electrolyte prepared by the above-mentioned preparation method, and the above-mentioned separator, and has excellent electrochemical performance, which is suitable for wide application. BRIEF DESCRIPTION OF DRAWINGS

[0046] Fig. 1 is a structural schematic diagram of a solid-state electrolyte in some embodiments of the present application;

[0047] Fig. 2 is a preparation process diagram of a solid-state electrolyte in some embodiments of the present application;

[0048] Fig. 3 is an SEM diagram of a crystallized substance in Example 1 of the present application (with a magnification of 50K);

[0049] Fig. 4 is an SEM diagram of a solid-state electrolyte in Example 1 of the present application (with a magnification of 30K);

[0050] Fig. 5 is an SEM diagram of a solid-state electrolyte in Example 1 of the present application (with a magnification of 50K);

[0051] Fig. 6 is an XRD diagram of a solid-state electrolyte in Example 1 of the present application;

[0052] Fig. 7 is an infrared spectrum diagram of a solid-state electrolyte in Example 1 of the present application. DETAILED DESCRIPTION

[0053] To make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0054] Fig. 1 is a structural schematic diagram of a solid-state electrolyte in some embodiments of the present application. As shown in Fig. 1, the first aspect of the present application provides a solid-state electrolyte, which includes a silico-aluminate and an oxide electrolyte body.

[0055] The solid-state electrolyte is a porous Na-Y type cage structure.

[0056] In the present application, the silicoaluminate is used to form a molecular sieve, and the silicoaluminate can be a silicoaluminate commonly used in the art to form a molecular sieve. For example, the silicoaluminate can be sodium silicoaluminate. The oxide electrolyte body refers to an oxide solid electrolyte commonly used in the art. For example, the oxide electrolyte body can be at least one of LATP, LAGP, LTP, LLZO, LZGO, LLTO, LLNO, and LLZTO. The porous Na-Y cage structure can be understood as a Na-Y cage structure containing a plurality of pores. In some embodiments, the pores can be multi-level pores, for example, at least two of micropores, mesopores, and macropores. The porous Na-Y cage structure can be a porous octahedral cage structure.

[0057] The solid electrolyte of the present application comprises a disordered interpenetrating network structure formed by a silicoaluminate and an oxide electrolyte body, and the network structure is a multi-level pore Na-Y cage structure. The oxide electrolyte body is alkaline (for example, pH is 8-9), and the Lewis acid sites of the silicoaluminate are matched with the oxide electrolyte body to enhance the adsorption between the silicoaluminate and the oxide electrolyte body, thereby improving the structural stability of the solid electrolyte and helping to prolong the service life of the battery. The multi-level pore Na-Y cage structure not only provides a channel for the transmission of metal ions and improves the transmission performance of metal ions, but also stores metal ions and improves the interface performance between the solid electrolyte and the positive and negative electrodes. Therefore, the solid electrolyte of the present application has excellent mechanical properties, ion transmission performance, and interface performance, and when applied to a battery, it can prolong the service life of the battery and improve the electrochemical performance of the battery.

[0058] In some embodiments, the oxide electrolyte body is LATP, and the Ti element has a valence of +3 and +4 at high and low potentials. The LATP with a valence of +4 acts as a mixed ionic and electronic conductor, which is conducive to regulating the lithium ion flux at the interface. The LATP is embedded in a cage to form an internal through-hole ion and electron conduction path, thereby providing a path for the transmission of lithium ions within the solid electrolyte and improving the migration rate of the particles.

[0059] In some embodiments of the present application, when the mass ratio of the silicoaluminate to the oxide electrolyte body in the solid electrolyte is (2-5): 1, a multi-level pore structure with stable structure can be formed with less oxide electrolyte body in the solid electrolyte body, and an ion storage buffer layer can be better formed to improve the ion conductivity and interface performance of the solid electrolyte. In some embodiments of the present application, the mass ratio of the silicoaluminate to the oxide electrolyte body can be determined according to the addition amount of the silicoaluminate and the addition amount of the oxide electrolyte body during preparation.

[0060] Further, when the molar ratio of silicon to aluminum in the solid-state electrolyte is (2-3): 1, the formed porous structure has more stable performance, which helps to improve the structural stability of the solid-state electrolyte.

[0061] In some embodiments of the present application, the solid-state electrolyte has a chain alkyl group in the pores. That is, the solid-state electrolyte has a chain alkyl group bonded and / or has a free chain alkyl group in the pores.

[0062] The chain alkyl group can be a straight-chain alkyl group or a branched-chain alkyl group. In some embodiments, the chain alkyl group can be an alkyl group with a carbon number of twelve or more than twelve.

[0063] When the solid-state electrolyte has a long-chain alkyl group in the pores, the hydrophobicity of the pores can be maintained, the hygroscopicity and water content of the solid-state electrolyte can be greatly reduced, and the solid-state electrolyte can be prepared into an aqueous slurry for coating, thereby widening the application of the solid-state electrolyte.

[0064] In some embodiments of the present application, when the average particle size of the solid-state electrolyte is 0.2-2 μm, the ion transmission performance of the solid-state electrolyte can be improved while ensuring the stability of the solid-state electrolyte.

[0065] Further, when the average pore size of the solid-state electrolyte is 1-100 nm, the ion transmission performance and the interface performance of the solid-state electrolyte can be improved while improving the stability of the solid-state electrolyte.

[0066] When the specific surface area of the solid-state electrolyte is ≥300 m 2 / g, the ion transmission performance and the interface performance of the solid-state electrolyte can be further improved;

[0067] In some embodiments of the present application, the pore volume ratio of the solid-state electrolyte is 20-40%.

[0068] The pore volume ratio of the solid-state electrolyte refers to the ratio of the total volume of the pores in the solid-state electrolyte to the total volume of the solid-state electrolyte. When the pore ratio of the solid-state electrolyte is 20-40%, the solid-state electrolyte has excellent structural stability, and can also store more metal ions to provide channels for the transmission of metal ions, thereby improving the interface performance and ion transmission capacity of the battery.

[0069] FIG. 2 is a preparation process diagram of the solid-state electrolyte in some embodiments of the present application. As shown in FIG. 2, the second aspect of the present application provides a preparation method of the solid-state electrolyte of the first aspect, which comprises:

[0070] The alkyl surfactant and the oxide electrolyte body are subjected to a first mixing treatment to obtain an alkyl surfactant-coated solid-state electrolyte template micelle;

[0071] The Y-type precursor is subjected to a second mixing treatment with the solid electrolyte template micelles to obtain a guiding micelle, and a silicon source, an aluminum source and a sodium source are added to the guiding micelle to obtain a reaction solution;

[0072] The reaction solution is subjected to a hydrothermal crystallization reaction and a calcination treatment in sequence to obtain the solid electrolyte.

[0073] In the present application, the alkyl surfactant is used for modifying the oxide electrolyte body, and the alkyl surfactant has the functions of pore pre-filling and structure guiding, which can promote the formation of a porous structure in the subsequent hydrothermal crystallization reaction. The alkyl surfactant can be a commonly used alkyl surfactant in the art. In some embodiments, the alkyl surfactant can be an aliphatic ammonium salt. For example, the alkyl surfactant can be selected from at least one of cetyl dimethyl ammonium chloride, octadecyl trimethyl ammonium chloride, dodecyl dimethyl amine oxide, cetyl trimethyl ammonium bromide, octadecyl dimethyl benzyl ammonium chloride, and [3-(trimethoxysilyl)propyl] octadecyl dimethyl ammonium chloride.

[0074] The Y-type precursor refers to an imperfect sol-like precursor of a porous material to be obtained, which is used to form a Na-Y type multi-level pore cage structure in a hydrothermal purification reaction. The Y-type precursor can be prepared by a method commonly used in the art. For example, the Y-type precursor is prepared by a method comprising the following steps:

[0075] A first mixed system is obtained by mixing water glass, NaOH, NaAlO2 and deionized water, and the first mixed system is subjected to a first stirring treatment and an aging treatment in sequence to obtain a Y-type directing agent (the Y-type directing agent refers to a directing agent with a ligand shape that guides the assembly of molecules to form a highly ordered structure in the growth and crystallization process of a multi-level pore cage-shaped solid electrolyte, which provides space before crystal growth and has a guiding effect on crystal growth);

[0076] A second mixed system is obtained by stirring and mixing water glass and deionized water, and the Y-type directing agent is added dropwise to the second mixed system. After a second stirring treatment, the Y-type precursor is obtained.

[0077] The first mixed system comprises, in terms of mass fraction, water glass 20-30 parts, NaOH 7-9 parts, NaAlO2 1-5 parts, and deionized water 60-65 parts.

[0078] For example, the first mixing system can include, in terms of mass fraction: water glass 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, or a range consisting of any two of them; NaOH 7 parts, 7.5 parts, 8 parts, 8.5 parts, 9 parts, or a range consisting of any two of them; NaAlO2 1 part, 2 parts, 3 parts, 4 parts, 5 parts, or a range consisting of any two of them; deionized water 60 parts, 61 parts, 62 parts, 63 parts, 64 parts, 65 parts, or a range consisting of any two of them;

[0079] The first stirring treatment can be a magnetic stirring treatment, and in the first stirring treatment, the rotation speed is 200-600 rpm, and the time is 3-5 h; in the aging treatment, the temperature is room temperature (25-30℃), and the time is 40-48 h, so that the solid-state electrolyte with a Na-Y type cage structure can be formed;

[0080] In the second stirring treatment, the raw materials include, in terms of mass fraction: water glass 35-45 parts, deionized water 5-7 parts, and Y type directing agent 6-10 parts; the rotation speed is 200-300 rpm, and the time is 4-7 h; by slowly dropping the Y type directing agent into the second mixing system and controlling the rotation speed and time of the second stirring treatment, the aluminum element in the water glass can be better coated on the surface of the Y type directing agent, so as to provide more sufficient aluminum source for the growth of the crystal and avoid the self-aggregation of the water glass.

[0081] The application does not particularly limit the aluminum source, and the aluminum source can be a compound containing an aluminum element commonly used in the art. For example, the aluminum source can be at least one of aluminum isopropylate, aluminum sulfate, sodium metaaluminate, aluminum nitrate, and aluminum trihydrate;

[0082] The application does not particularly limit the silicon source, and the silicon source can be a compound containing a silicon element commonly used in the art. For example, the silicon source can be at least one of silica sol, water glass, white carbon black, sodium silicate, and orthosilicic acid;

[0083] The application does not particularly limit the sodium source, and the sodium source can be a compound containing a sodium element commonly used in the art. For example, the sodium source can be at least one of sodium hydroxide, sodium oxide, sodium peroxide, and sodium chlorate.

[0084] Specifically, the alkyl surfactant is mixed with the oxide electrolyte body for the first mixing treatment, and the surfactant is used to modify the oxide electrolyte body, which is helpful for better forming a hierarchical pore structure and obtaining an alkyl surfactant-coated solid-state electrolyte template micelle;

[0085] The Y-type precursor is subjected to a second mixing treatment with the solid electrolyte template micelles, so that the Y-type precursor and the solid electrolyte template micelles are uniformly mixed to obtain a guiding micelle with a guiding function; then, a silicon source, an aluminum source and a sodium source are added to the guiding micelle to form a reaction solution; then, the reaction solution is subjected to a hydrothermal crystallization reaction, and in the hydrothermal crystallization process, the molecular sieve grows around the solid electrolyte template micelles to form a crystalline product including an oxide electrolyte body and a silico-aluminate, and then a calcination treatment is performed to remove groups (for example, ammonium halide) in the surfactant except for alkyl groups, so as to form a multi-level pore Na-Y type cage-shaped solid electrolyte with the silico-aluminate and the oxide electrolyte body interpenetrating.

[0086] In the present application, the oxide electrolyte body and the alkyl surfactant are subjected to a first mixing treatment to prepare the solid electrolyte template micelles coated with the alkyl surfactant. Compared with the pure oxide electrolyte body, the solid electrolyte template micelles obtained in the present application have the advantage of flexible and variable structure, and the oxide electrolyte body can be perfectly reserved in the molecular sieve and the channel in the subsequent calcination treatment. The preparation method of the present application can obtain a multi-level pore Na-Y type cage-shaped solid electrolyte with uniform pore size (uniform mesopore) and high crystallinity, and compared with the etching method, the preparation method of the present application has a lower requirement on the particle size of the oxide electrolyte body (the particle size can be 10-150 nm), is simple to operate, and is suitable for more extensive popularization and application.

[0087] In some embodiments of the present application, the first mixing treatment includes: mixing the alkyl surfactant with water, adjusting the pH to 4.5-6.5, performing ultrasonic dispersion, and then adding the oxide electrolyte body to obtain the solid electrolyte template micelles.

[0088] Specifically, the alkyl surfactant can be mixed with water to obtain a mixed system, the pH of the mixed system is adjusted to 4.5-6.5, and then ultrasonic dispersion is performed to uniformly disperse the alkyl surfactant, which is helpful for uniform dispersion of the oxide electrolyte body, so as to obtain more uniform solid electrolyte template micelles, which is helpful for subsequent formation of a solid electrolyte with uniform pore size distribution. In the present application, under the condition that the pH is 4.5-6.5, the oxide electrolyte body is more likely to form the solid electrolyte template micelles coated with the alkyl surfactant, which in turn guides the formation of the chimeric multi-level pore cage-shaped solid electrolyte in the hydrothermal crystallization reaction.

[0089] Further, in the first mixing treatment, concentrated hydrochloric acid can be used to adjust the pH of the mixed system. The concentration of the concentrated hydrochloric acid is 12 mol / L.

[0090] In some embodiments, the mass ratio of the alkyl surfactant, water and concentrated hydrochloric acid is (1-3):20:1; the ultrasonic dispersion time can be 5-60 min;

[0091] After the oxide electrolyte body is added, stirring treatment can also be carried out at room temperature for 3-4h to promote uniform mixing of the alkyl surfactant and the oxide electrolyte.

[0092] In some embodiments of the present application, when the temperature in the hydrothermal crystallization reaction is 110-120℃ and the time is 10-14h, the hydrothermal crystallization reaction can be made more complete, the solid-state electrolyte with a suitable silicon-aluminum ratio and uniform growth can be obtained, the lithium storage stability of the battery is improved when the solid-state electrolyte is applied to the battery, thereby improving the capacity of the battery, and it can be ensured that the growth product of the hydrothermal crystallization reaction is in the form of a mixture of water powder, which is helpful for the subsequent coating process.

[0093] When the temperature in the calcination treatment is 260-300℃ and the time is 4-8h, the alkyl groups can be retained while other groups (ammonium halide) in the alkyl surfactant are more fully removed, and a solid-state electrolyte with excellent comprehensive performance can be obtained.

[0094] In some embodiments, the Y-type precursor can be subjected to a second mixing treatment with the solid-state electrolyte template micelles to obtain a directing micelle; the silicon source, the aluminum source, the sodium source, and the deionized water are subjected to stirring treatment at a rate of 500-2000rpm at room temperature for 1-2h, then the directing micelle is added dropwise, and the stirring rate is increased as the dropwise addition process increases, and after the dropwise addition is completed, the stirring is fully carried out for 2-4h to obtain a reaction solution. Among them, for every a parts of the directing micelle, the stirring rate is increased by 3a-5a.

[0095] Further, in the reaction solution, the mass ratio of the Y-type precursor, the solid-state electrolyte template micelles, the silicon source, the aluminum source, and the sodium source can be (45-60):(10-40):(20-40):(2-5):(1-1.5).

[0096] In some embodiments, the reaction solution can be moved to a hydrothermal reaction kettle, a hydrothermal crystallization reaction is carried out in the hydrothermal reaction kettle to obtain a crystalline product, then the crystalline product is subjected to washing treatment, suction filtration 3-5 times, and after drying at 60℃ under a blast, calcination treatment is carried out in a muffle furnace, followed by grinding to obtain a solid-state electrolyte with a particle size of 0.2-2 microns.

[0097] The third aspect of the present application provides a separator, comprising a separator substrate and a solid-state electrolyte layer arranged on at least one surface of the separator substrate and / or at least part of the pores,

[0098] The solid-state electrolyte layer comprises the solid-state electrolyte of the first aspect; or, the solid-state electrolyte layer comprises the solid-state electrolyte prepared by the preparation method of the second aspect.

[0099] In the present application, the separator substrate can be a porous membrane commonly used in the art. For example, the porous membrane can be a membrane or a fabric substrate formed of any one of polymers, or a multi-layer composite membrane formed by compounding a membrane or a fabric substrate formed of any one of polymers. The polymer can be, for example, at least one selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, polymethyl methacrylate, polyacetal, polyamide, polycarbonate, polyimide, polyether ether ketone, polyether sulfone, polyphenylene ether, polyphenylene sulfide, polyvinyl naphthalene, polyvinylidene fluoride, polyethylene oxide, polyacrylonitrile, tetrafluoro-propylene copolymer, hexafluoro-propylene copolymer, polyethylene, and polypropylene. The multi-layer composite membrane can be, for example, at least one selected from the group consisting of an alumina-coated composite membrane, a boehmite ceramic-coated composite membrane, a fluorine-containing polymer-coated composite membrane, and a nanofiber-coated composite membrane. Further, the separator substrate is a polyolefin separator.

[0100] The present application does not specifically limit the pore size and porosity of the separator substrate, and for example, can be preferably 0.5 to 100 μm and 10 to 99%, respectively, and further can be preferably 0.5 to 50 μm and 30 to 70%, respectively.

[0101] The solid-state electrolyte layer of the present application includes the solid-state electrolyte of the first aspect or the solid-state electrolyte prepared by the preparation method of the second aspect.

[0102] In the present application, the surface of the separator substrate refers to two surfaces of the separator substrate having the largest area and being oppositely disposed. The solid-state electrolyte layer can be disposed on one surface of the separator substrate to form a separator, or the solid-state electrolyte layer can be disposed on both surfaces of the separator substrate to form a separator, or the solid-state electrolyte layer can be disposed on the surface of the separator substrate and in the pores to form a solid-state electrolyte layer.

[0103] The separator of the present application has excellent ion transport performance and interface compatibility because it includes the solid-state electrolyte of the first aspect or the solid-state electrolyte prepared by the preparation method of the second aspect.

[0104] In some embodiments, the solid-state electrolyte can be prepared as a coating slurry, and then the coating slurry can be disposed on at least one surface of the separator substrate to form a separator including a solid-state electrolyte layer.

[0105] Further, when the thickness of the separator substrate is 2 to 20 μm, the ion conduction performance of the battery can be further improved while increasing the energy density of the battery. In particular, when the thickness of the solid-state electrolyte layer is 0.5 to 5 μm, the obtained separator can further improve the energy density, rate performance, and cycle performance of the battery when applied to the battery.

[0106] In some embodiments of the present application, when the bulk density of the solid-state electrolyte layer is 1-1.2 g / cm3, the obtained separator can further improve the electrochemical performance of the battery when applied to the battery. The bulk density refers to the mass of the solid-state electrolyte in the solid-state electrolyte layer per unit volume.

[0107] Further, when the ratio of the thickness of the solid-state electrolyte layer to the thickness of the separator is ≤20%, the separator satisfies one of the following:

[0108] a) the thermal shrinkage rate of the separator at 150°C is ≤3%;

[0109] b) the air permeability value of the separator increases by 10-30 s / 100cc;

[0110] c) the electrochemical stability window of the separator is ≥5.1V (the resistance of the separator to oxidation and reduction under a working voltage of 5.1V or above), and the separator can further improve the electrochemical performance of the battery when applied to the battery.

[0111] In some embodiments of the present application, the separator further comprises an electrolyte filled in the pores of the solid-state electrolyte layer. Specifically, the pores between any two solid-state electrolytes of the solid-state electrolyte layer and the pores of each solid-state electrolyte are filled with electrolyte, thereby forming a solid-liquid mixed state separator. In the separator of the present application, not only are there pores between any two solid-state electrolytes, but each solid-state electrolyte also has pores itself, which can provide more storage space for the electrolyte and improve the electrochemical performance of the battery.

[0112] A fourth aspect of the present application provides a battery comprising the solid-state electrolyte of the first aspect; or,

[0113] the solid-state electrolyte prepared by the preparation method of the second aspect; or,

[0114] the separator of the third aspect.

[0115] It can be understood that the battery of the present application also comprises a positive electrode sheet, a negative electrode sheet, and an outer package. In the present application, the positive electrode sheet, the separator, and the negative electrode sheet are stacked to obtain an electrode assembly, and the electrode assembly is placed in the outer package to obtain the battery after sealing.

[0116] The battery of the present application has excellent electrochemical performance, excellent user experience, and is suitable for wide application because it comprises any one of the above-mentioned solid-state electrolyte, the solid-state electrolyte prepared by the preparation method, and the separator.

[0117] In the following, the technical solutions of the present application are described in detail through specific examples.

[0118] Example 1

[0119] The battery of the embodiment is prepared by a method comprising the following steps:

[0120] 1) Preparation of solid electrolyte

[0121] a. A first mixed system is obtained by mixing water glass, NaOH, NaAlO2 and deionized water, and the first mixed system is sequentially subjected to first stirring treatment and aging treatment at room temperature to obtain a Y-type directing agent;

[0122] A second mixed system is obtained by stirring and mixing water glass and deionized water, and the Y-type directing agent is added dropwise into the second mixed system, and after second stirring treatment, a Y-type precursor is obtained;

[0123] In the first mixed system, the mass fractions of water glass, NaOH, NaAlO2 and deionized water are 20, 9, 2 and 60, respectively; the first stirring treatment is magnetic stirring treatment, and in the first stirring treatment, the rotation speed is 500 rpm and the time is 3 h; in the aging treatment, the time is 48 h;

[0124] In the second stirring treatment, the raw materials are included in the mass fractions of 40 parts of water glass, 7 parts of deionized water and 8 parts of Y-type directing agent; the rotation speed is 300 rpm and the time is 5 h;

[0125] b. The alkyl surfactant, water and concentrated hydrochloric acid are mixed and then subjected to ultrasonic dispersion for 20 min, and the oxide electrolyte body is added, and the stirring is performed at a rotation speed of 500 rpm for 6 h at room temperature to obtain a solid electrolyte template micelle;

[0126] The alkyl surfactant is hexadecyl trimethyl ammonium bromide, and the oxide electrolyte body is titanium aluminum lithium phosphate;

[0127] The mass ratio of the alkyl surfactant, water, concentrated hydrochloric acid and oxide electrolyte body is 2:20:1:10;

[0128] c. The Y-type precursor and the solid electrolyte template micelle are subjected to second mixing treatment to obtain a directing micelle; the silicon source, the aluminum source, the sodium source and the deionized water are subjected to stirring treatment at a rotation speed of 1000 rpm for 2 h at room temperature, then the directing micelle is added dropwise, and the stirring speed is increased with the progress of the dropwise addition, and after the dropwise addition is completed, the stirring is performed fully for 4 h to obtain a reaction solution;

[0129] The mass ratio of the Y-type precursor, the solid electrolyte template micelle, the silicon source, the aluminum source and the sodium source is 50:15:28:2.5:1.5; for every a parts of the directing micelle, the stirring speed is increased by 100a;

[0130] The silicon source is water glass, the aluminum source is sodium metaaluminate, and the sodium source is sodium hydroxide;

[0131] d. The solution to be reacted is moved to a hydrothermal reactor, and a hydrothermal crystallization reaction is performed in the hydrothermal reactor to obtain a crystallized product. The crystallized product is then subjected to a washing treatment, suction filtration 3-5 times, and drying at 60°C in a blast oven. Then, a calcination treatment is performed in a muffle furnace, followed by grinding to obtain a solid-state electrolyte;

[0132] In the hydrothermal crystallization reaction, the temperature is 115°C, and the time is 12h. In the calcination treatment, the temperature is 300°C, and the time is 6h.

[0133] The solid-state electrolyte is subjected to performance detection. The solid-state electrolyte includes a silicoaluminate and an oxide electrolyte body, and has a porous Na-Y type cage structure. The mass ratio of the silicoaluminate to the oxide electrolyte body is 3.9:1. The solid-state electrolyte has a chain alkyl in the pores. The specific parameters of the solid-state electrolyte are shown in Table 1.

[0134] 2) Preparation of a separator

[0135] The solid-state electrolyte prepared in step 1) is prepared into a coating slurry, which is then arranged on both surfaces of a separator substrate. After drying, a separator including a solid-state electrolyte layer is formed.

[0136] The solid content of the coating slurry is 35%. The solid-state electrolyte layer includes the solid-state electrolyte prepared in step 1), a dispersant BYK-3004 (purchased from BYK-Chemical), and a binder LIS-S104 (purchased from Shanghai Sanrui High Polymer Material Co., Ltd.). The mass percentage of the solid-state electrolyte is 93%, the mass percentage of the dispersant is 1%, and the mass percentage of the binder is 6%.

[0137] The total thickness of the solid-state electrolyte layer is 2μm, and the bulk density of the solid-state electrolyte layer is 1.1g / cm 3 ;

[0138] The separator substrate is a polyolefin separator with a thickness of 9μm.

[0139] 3) Preparation of a battery

[0140] The positive electrode sheet, the separator, and the negative electrode sheet are arranged in layers to obtain an electrode assembly. The electrode assembly is placed in an aluminum plastic film, electrolyte is injected, and the battery is sealed.

[0141] The positive electrode sheet includes an aluminum foil and a positive electrode active layer arranged on the surface of the aluminum foil. The positive electrode active layer includes lithium cobaltate, a conductive agent Super P, and a binder PVDF. The mass ratio of lithium cobaltate, the conductive agent, and the binder is 96:2:2.

[0142] The negative electrode sheet comprises a copper foil and a negative active layer arranged on the surface of the copper foil, the negative active layer comprising silicon-doped graphite, conductive agent Super P and binder PAA, and the mass ratio of the silicon-doped graphite, the conductive agent and the binder being 95:2:3.

[0143] The electrolyte is 1.0M LiPF6 electrolyte, and the solvent in the electrolyte is EC, EMC and DMC, and the volume ratio of EC, EMC and DMC is 1:1:1.

[0144] Example 2

[0145] The method for preparing the battery of the present example is different from that of Example 1 only in that:

[0146] 1) Preparation of solid electrolyte

[0147] a. In the first mixing system, the mass fractions of water glass, NaOH, NaAlO2 and deionized water are 25, 7, 2 and 60, respectively; in the first stirring treatment, the rotation speed is 700 rpm and the time is 4h;

[0148] In the second stirring treatment, the raw materials include, by mass fraction, water glass 45 parts, deionized water 5 parts and Y-type directing agent 10 parts; the rotation speed is 500 rpm and the time is 6h;

[0149] b. The mass ratio of the alkyl surfactant, water, concentrated hydrochloric acid and oxide electrolyte body is 2:17:1:10;

[0150] c. The mass ratio of the Y-type precursor, solid electrolyte template micelles, silicon source, aluminum source and sodium source is 60:15:32:3:1.5;

[0151] The mass ratio of the silicate and the oxide electrolyte body in the solid electrolyte is 3.5:1.

[0152] 2) Preparation of the separator

[0153] The bulk density of the solid electrolyte layer is 1.0g / cm 3 .

[0154] Example 3

[0155] The method for preparing the battery of the present example is different from that of Example 1 only in that:

[0156] 1) Preparation of solid electrolyte:

[0157] a. In the first mixing system, the mass fractions of water glass, NaOH, NaAlO2 and deionized water are 20, 9, 3 and 65, respectively;

[0158] In the second stirring treatment, the mass fractions of each raw material include: water glass 35 parts, deionized water 7 parts, and Y-type directing agent 6 parts; the rotating speed is 500 rpm, and the time is 6 h;

[0159] b. The mass ratio of the alkyl surfactant, water, concentrated hydrochloric acid, and oxide electrolyte body is 2:20:1:5;

[0160] c. The mass ratio of the Y-type precursor, solid electrolyte template micelles, silicon source, aluminum source, and sodium source is 45:11:26:4:1.5;

[0161] The mass ratio of the silicate and oxide electrolyte body in the solid electrolyte is 4.8:1.

[0162] Example 4

[0163] The method for preparing the battery of the present example is different from that of Example 1 only in that:

[0164] 1) Preparation of the solid electrolyte:

[0165] a. In the aging treatment, the time is 40 h;

[0166] In the second stirring treatment, the rotating speed is 200 rpm, and the time is 4 h;

[0167] b. The alkyl surfactant, water, and concentrated hydrochloric acid are mixed, and then ultrasonic dispersion is performed for 5 min. The oxide electrolyte body is added, and stirring is performed at a rotating speed of 300 rpm at room temperature for 3 h to obtain the solid electrolyte template micelles;

[0168] The alkyl surfactant is octadecyl dimethyl benzyl ammonium chloride.

[0169] c. The Y-type precursor and the solid electrolyte template micelles are subjected to a second mixing treatment to obtain the directing micelles. The silicon source, aluminum source, sodium source, and deionized water are subjected to stirring treatment at a rotating speed of 500 rpm at room temperature for 1 h;

[0170] d. The hydrothermal crystallization reaction temperature is 110°C, and the time is 10 h.

[0171] Example 5

[0172] The method for preparing the battery of the present example is different from that of Example 1 only in that:

[0173] 1) Preparation of the solid electrolyte:

[0174] a. In the first mixing system, the mass fractions of water glass, NaOH, NaAlO2, and deionized water are 25, 8, 3, and 60, respectively. In the first stirring treatment, the rotating speed is 200 rpm, and the time is 3 h. In the aging treatment, the time is 45 h;

[0175] In the second stirring treatment, each raw material includes, by mass fraction: silica sol 40 parts, deionized water 6 parts, and Y-type directing agent 7 parts; the rotation speed is 200 rpm, and the time is 4 h;

[0176] b. The alkyl surfactant is octadecyl trimethyl ammonium chloride;

[0177] c. The mass ratio of the Y-type precursor, the solid electrolyte template micelle, the silicon source, the aluminum source, and the sodium source is 55:15:23:2:1.5; the silicon source is silica sol, the aluminum source is sodium metaaluminate, and the sodium source is sodium chlorate and sodium oxide (the mass ratio of sodium chlorate to sodium chloride is 1:3);

[0178] d. In the hydrothermal crystallization reaction, the temperature is 120°C, and the time is 10 h; in the calcination treatment, the temperature is 270°C, and the time is 6 h;

[0179] The mass ratio of the silicate and aluminate in the solid electrolyte to the oxide electrolyte body is 4.3:1.

[0180] Example 6

[0181] The method of preparing the battery of this example is distinguished from that of Example 1 only in that:

[0182] 1) Preparation of the solid electrolyte:

[0183] a. In the second stirring treatment, each raw material includes, by mass fraction: white carbon black 40 parts, deionized water 7 parts, and Y-type directing agent 8 parts;

[0184] b. The alkyl surfactant is dodecyl dimethyl amine oxide;

[0185] The mass ratio of the alkyl surfactant, water, concentrated hydrochloric acid, and the oxide electrolyte body is 0.5:20:2:10;

[0186] c. The mass ratio of the Y-type precursor, the solid electrolyte template micelle, the silicon source, the aluminum source, and the sodium source is 48:12:22:3:1.5; the silicon source is white carbon black, the aluminum source is aluminum sulfate, and the sodium source is sodium peroxide;

[0187] d. In the hydrothermal crystallization reaction, the temperature is 100°C, and the time is 16 h;

[0188] The mass ratio of the silicate and aluminate in the solid electrolyte to the oxide electrolyte body is 4.7:1.

[0189] 2) Preparation of the separator

[0190] The bulk density of the solid electrolyte layer is 0.9 g / cm 3 .

[0191] Example 7

[0192] The method for preparing the battery of the present embodiment is different from that of Example 1 only in that:

[0193] 1) Preparation of the solid electrolyte:

[0194] In the first mixing system, the mass fractions of water glass, NaOH, NaAlO2 and deionized water are 18, 9, 2 and 60, respectively;

[0195] In the second stirring treatment, the raw materials include, by mass fraction, water glass 35 parts, deionized water 7 parts and Y-type directing agent 8 parts;

[0196] The mass ratio of the silico-aluminate and the oxide electrolyte body in the solid electrolyte is 3.7:1.

[0197] Example 8

[0198] The method for preparing the battery of the present embodiment is different from that of Example 1 only in that:

[0199] 1) Preparation of the solid electrolyte:

[0200] In the first mixing system, the mass fractions of water glass, NaOH, NaAlO2 and deionized water are 24, 9, 2 and 60, respectively;

[0201] In the second stirring treatment, the raw materials include, by mass fraction, water glass 45 parts, deionized water 7 parts and Y-type directing agent 8 parts;

[0202] The mass ratio of the silico-aluminate and the oxide electrolyte body in the solid electrolyte is 4.2:1.

[0203] Comparative Example 1

[0204] The method for preparing the battery of the present comparative example is different from that of Example 1 only in that:

[0205] 1) Preparation of the solid electrolyte

[0206] b. Add the oxide electrolyte body to pure water, ultrasonically disperse for 5 min, and stir at a speed of 500 rpm for 6 h at room temperature to obtain a solid electrolyte dispersion;

[0207] The oxide electrolyte body is titanium aluminum lithium phosphate;

[0208] The mass ratio of water to the oxide electrolyte body is 2:1;

[0209] c. Perform a second mixing treatment on the Y-type precursor and the solid electrolyte dispersion;

[0210] d. After blowing and drying, do not perform a calcination treatment, and directly perform grinding to obtain the solid electrolyte;

[0211] The solid electrolyte is embedded, and the multi-level pore structure is not present.

[0212] 2) Preparation of the separator

[0213] The solid electrolyte layer has a bulk density of 1.25 g / cm 3 .

[0214] Comparative Example 2

[0215] The method for preparing the battery of the present comparative example is only different from that of Example 1 in that:

[0216] 1) Preparation of the separator

[0217] The oxide electrolyte LATP is prepared into a coating slurry, and then the coating slurry is arranged on both surfaces of the separator substrate. After drying, the electrolyte is injected to form a separator comprising a solid electrolyte layer;

[0218] The total thickness of the solid electrolyte layer is 2 μm, and the bulk density of the solid electrolyte layer is 1.3 g / cm 3 .

[0219] The separator substrate is a polyolefin separator, and the thickness is 9 μm.

[0220] Comparative Example 3

[0221] The method for preparing the battery of the present comparative example is only different from that of Example 1 in that:

[0222] 1) Preparation of the solid electrolyte

[0223] b. The alkyl surfactant, water and concentrated hydrochloric acid are mixed and then ultrasonically dispersed for 20 min to obtain a template micelle, and no oxide electrolyte body is added;

[0224] The mass ratio of the alkyl surfactant, water and concentrated hydrochloric acid is 2:20:1;

[0225] c. The Y-type precursor is subjected to a second mixing treatment with the template micelle to obtain a guiding micelle;

[0226] The mass ratio of the Y-type precursor, the template micelle, the silicon source, the aluminum source and the sodium source is 50:15:25:5:1.5;

[0227] 2) Preparation of the separator

[0228] The bulk density of the solid electrolyte layer is 0.85 / cm 3 .

[0229] Comparative Example 4

[0230] The method for preparing the battery of the present comparative example is only different from that of Example 1 in that:

[0231] 1) Preparation of solid-state electrolyte

[0232] a. mixing the oxide electrolyte body and deionized water, stirring at room temperature at a speed of 500 rpm for 6 h to obtain a solid-state electrolyte dispersion liquid;

[0233] The oxide electrolyte body is lithium aluminum titanium phosphate.

[0234] The mass ratio of water to the oxide electrolyte body is 20:10.

[0235] b. performing second mixing treatment on the Y-type precursor with the solid-state electrolyte dispersion liquid to obtain a guiding dispersion liquid;

[0236] Each drop of a portion of the guiding dispersion liquid corresponds to an increase of 20a in stirring speed.

[0237] c. mixing the alkyl surfactant, water and concentrated hydrochloric acid, then performing ultrasonic dispersion for 20 min, and stirring for 2 h at a speed of 500 rpm to obtain a guiding pore-forming micelle;

[0238] The alkyl surfactant is cetyltrimethylammonium bromide.

[0239] The mass ratio of the alkyl surfactant, water and concentrated hydrochloric acid is 2:20:1.

[0240] d. moving the guiding dispersion liquid into a hydrothermal reaction kettle, performing hydrothermal crystallization reaction in the hydrothermal reaction kettle to obtain a crystalline product, then adding the guiding pore-forming micelle dropwise in the hydrothermal reaction kettle, stirring at a speed of 500 rpm for 6 h, then performing washing treatment on the crystalline product, performing suction filtration for 3-5 times, and performing air drying at 60℃, then performing calcination treatment in a muffle furnace, followed by grinding to obtain a solid-state electrolyte;

[0241] The solid-state electrolyte only forms a hierarchical pore structure and cannot form a cage-like embedding system.

[0242] 2) Preparation of separator

[0243] The bulk density of the solid-state electrolyte layer is 1.15 g / cm 3 .

[0244] Performance test

[0245] The solid-state electrolyte, the separator and the battery in the examples and the comparative examples were subjected to the following performance tests, and the results are shown in Table 1.

[0246] 1. Morphology

[0247] The morphology of the solid-state electrolyte in Example 1 was observed using SEM (HITACHI, Japan, model: HITACHI SU8010).

[0248] As can be seen from FIGS. 3-5, after the calcination treatment, the crystallization fills the surface in a form of a solid-state electrolyte with a microporous structure, indicating that the low-temperature calcination treatment can remove the ammonium halide component in the pores and maintain the uniformity of the pore structure.

[0249] 2. XRD test

[0250] An X-ray diffractometer (Beijing Raytheon Science and Technology Co., Ltd., Model: D / MAX-Ultima Type IV, Cu Kα radiation, 5°<2θ<50°, 10° / min rate.

[0251] As can be seen from FIG. 6, the solid-state electrolyte in Example 1 of the present application has Bragg diffraction peaks of NaY-type zeolite at 2θ of 13.4°, 18.6°, 29.7°, and 31.8°, and the silicon-aluminum ratio is calculated to be 2.43:1 based on the main peak area of the silicon-aluminum elements.

[0252] 3. Infrared test

[0253] A Fourier transform infrared spectrometer (PerkinElmer, Model: spectrum two) is used for testing.

[0254] FIG. 7 is an infrared spectrum of the solid-state electrolyte in Example 1 of the present application. As can be seen from FIG. 7, the solid-state electrolyte in Example 1 of the present application has a TO4 tetrahedral bending peak at a wavelength of 470 cm -1 , a symmetric stretching vibration peak of the internal tetrahedron at a wavelength of 800 cm -1 , and an asymmetric stretching vibration peak of the tetrahedral atom at a wavelength of 1100-1200 cm -1 , indicating that the framework structure unit of the prepared solid-state electrolyte is a tetrahedral structure, which can form an eight-membered cage topology.

[0255] 4. Average particle size

[0256] The average particle size is tested by a particle size analyzer, and the test conditions are as follows: the solid-state electrolyte is dispersed in deionized water, and the test is performed after stirring and ultrasonic treatment for 10 s at 1500 rpm, the refractive index is 1.6, and the absorbance is 0.1.

[0257] 5. Average pore size

[0258] The average pore size is tested by a pore size analyzer (Beijing Jingmi Gaobote Science and Technology Co., Ltd., JW-112), the adsorbed gas is N2, the adsorption temperature is 77 K, V d is 23.2, the fixed value is set to 100.3 kPa, and the pore size is expressed in nm.

[0259] 6. Pore volume

[0260] The pore volume Vp The following formula is used to calculate:

[0261] V p =∫[V (BJH) ]d(logD)

[0262] wherein V (BJH) is determined by the adsorption isotherm obtained by nitrogen adsorption method using 3Flex (manufactured by Micromeritics Instrument Corp.) by BJH method,

[0263] D is the average pore diameter of the solid electrolyte.

[0264] 7, Specific surface area

[0265] The specific surface area is tested according to GB / T 19587-2004.

[0266] 8, Thermal shrinkage

[0267] Cut the separator to 130 mm x 130 mm, draw a 100 mm x 100 mm square line in the center, and place 5 A4 papers above and below. After heating treatment at 150°C for 1 hour in an oven, measure the size L (mm) of the drawn line after cooling to room temperature, and calculate the thermal shrinkage value according to the following formula:

[0268] Thermal shrinkage = (100-L) / 100*100%.

[0269] 9, Permeability value increment

[0270] The permeability value is determined according to the provisions of GB / T 36363-2018. Under the pressure of 1.21 kPa, the time required for 100 mL of air to pass through an area of 6.45 cm 2 The permeability values T1 and T2 of the separator and the corresponding separator substrate are tested, respectively. The permeability value increment is: ΔT = T1-T2.

[0271] 10, Ionic conductivity

[0272] Cut the separator sample to a diameter of 45 mm at a flat position, immerse the sample in electrolyte (1.0 M LiPF6 in 1:1:1 volume EC / EMC / DMC solvent) and seal for 30 min of immersion time; pour about 15 ml of fresh electrolyte (1.0 M LiPF6 in 1:1:1 volume EC / EMC / DMC solvent) into the test fixture, and test the bulk resistance using the electrochemical impedance spectroscopy (EIS) mode of the electrochemical workstation. The test conditions are: perturbation voltage amplitude 5 mV, frequency 10 mHz-1 MHz.

[0273] δ is the ionic conductivity (S / cm), L0 is the coated film thickness (cm); R b is the bulk resistance (Ω); S is the effective contact area of the separator with the test fixture (cm 2 ).

[0274] 11. Electrochemical stability window

[0275] In the flat position, cut a separator sample with a diameter of 19 mm, immerse the sample in an electrolyte (the solvent of the electrolyte is EC, EMC and DMC in a volume ratio of 1:1:1, and the solute is 1.0 M LiPF6), and seal, the soaking time is 30 min; using the assembly mode of stainless steel sheet / separator / lithium sheet, using the linear voltammetry scanning mode (LSV) of the electrochemical workstation to test the electrochemical stability window of the battery. Among them, the stainless steel sheet is the working electrode, the lithium sheet is the reference electrode, the measurement range is set to 0-6V, and the scanning speed is 1mV s -1 .

[0276] 12. Cycle performance

[0277] The battery test cycle instrument voltage setting range is 2.75-4.20V;

[0278] The cycle performance test is charged at a current density of 0.5C and discharged at a current density of 2C, and cycled 100 times in this way;

[0279] Cycle capacity retention rate = 100th discharge capacity / 1st discharge capacity*100%.

[0280] 13. Rate performance

[0281] The rate performance test is charged at a current density of 0.5C; then discharged at five gradient current densities of 0.5C, 1C, 2C, 3C and 4C in turn, and each gradient is cycled for 5 times to characterize the rate performance of the battery assembled by the separator;

[0282] Capacity retention rate = average value of 4C discharge capacity / average value of 0.5C discharge capacity*100%.

[0283] Table 1

[0284] As can be seen from Table 1, the separator including the composite solid electrolyte of the application has a low thermal shrinkage rate, a low air permeability value, a high ionic conductivity, and a high electrochemical stability window, and can improve the cycle performance and rate performance of the battery when applied to the battery;

[0285] Further, from Example 1 and Example 2-3, it can be seen that by further selecting the content of the silicon-aluminum ratio in the composite solid electrolyte, the composite solid electrolyte can reduce the thermal shrinkage rate, the gas permeation value of the separator, improve the ionic conductivity and the electrochemical stability window of the separator when applied to the separator, and improve the cycle performance and rate performance of the battery when applied to the battery.

[0286] From Example 1 and Example 4, it can be seen that by selecting the average pore size of the composite solid electrolyte, the composite solid electrolyte can reduce the thermal shrinkage rate, the gas permeation value of the separator, improve the ionic conductivity and the electrochemical stability window of the separator when applied to the separator, and improve the cycle performance and rate performance of the battery when applied to the battery.

[0287] From Example 1 and Example 5, it can be seen that by selecting the average particle size of the composite solid electrolyte, the composite solid electrolyte can reduce the thermal shrinkage rate, the gas permeation value of the separator, improve the ionic conductivity and the electrochemical stability window of the separator when applied to the separator, and improve the cycle performance and rate performance of the battery when applied to the battery.

[0288] From Example 1 and Example 6, it can be seen that by selecting the pore volume of the composite solid electrolyte, the composite solid electrolyte can reduce the thermal shrinkage rate, the gas permeation value of the separator, improve the ionic conductivity and the electrochemical stability window of the separator when applied to the separator, and improve the cycle performance and rate performance of the battery when applied to the battery.

[0289] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent substitutions for part or all of the technical features; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A solid electrolyte, wherein: The solid electrolyte includes an aluminosilicate and an oxide electrolyte body; The solid electrolyte is a porous Na-Y type cage structure.

2. The solid electrolyte according to claim 1, wherein In the solid electrolyte, the mass ratio of the aluminosilicate to the oxide electrolyte body is (2-5):

1.

3. The solid electrolyte according to claim 1 or 2, wherein In the solid electrolyte, the molar ratio of silicon element to aluminum element is (2-3):

1.

4. The solid electrolyte according to any one of claims 1 to 3, wherein The solid electrolyte has chain alkyl groups in its pores.

5. The solid electrolyte according to any one of claims 1 to 4, wherein The solid electrolyte satisfies one of the following conditions: a) the average particle size of the solid electrolyte is 0.2-2 μm; b) the average pore size of the solid electrolyte is 1-100 nm; c) The specific surface area of ​​the solid electrolyte is ≥300m 2 / g; d) The pore volume of the solid electrolyte accounts for 20-40%.

6. A method for preparing the solid electrolyte according to any one of claims 1 to 5, wherein: include: performing a first mixing treatment on an alkyl surfactant and an oxide electrolyte body to obtain solid electrolyte template micelles coated with the alkyl surfactant; performing a second mixing process on the Y-shaped precursor and the solid electrolyte template micelle to obtain a guiding micelle, and adding a silicon source, an aluminum source, and a sodium source to the guiding micelle to obtain a solution to be reacted; The solution to be reacted is subjected to a hydrothermal crystallization reaction and a calcination treatment in sequence to obtain the solid electrolyte.

7. The preparation method according to claim 6, wherein The first mixing treatment comprises: mixing the alkyl surfactant with water, adjusting the pH to 4.5-6.5, performing ultrasonic dispersion, and then adding the oxide electrolyte body to obtain solid electrolyte template micelles.

8. The preparation method according to any one of claims 6 to 7, wherein: The first mixing treatment further includes: adjusting the pH using concentrated hydrochloric acid.

9. The preparation method according to any one of claims 6 to 8, wherein The preparation method comprises one of the following: a) in the hydrothermal crystallization reaction, the temperature is 110-120° C. and the time is 10-14 h; b) During the calcination process, the temperature is 260-300° C. and the time is 4-8 hours.

10. A diaphragm, wherein: The invention comprises a diaphragm substrate and a solid electrolyte layer arranged on at least one surface and / or in at least part of the pores of the diaphragm substrate. The solid electrolyte layer comprises the solid electrolyte according to any one of claims 1 to 5; or, the solid electrolyte layer comprises the solid electrolyte prepared by the preparation method according to any one of claims 6 to 9. The diaphragm according to claim 10 , wherein: The diaphragm satisfies one of the following conditions: a) the thickness of the diaphragm substrate is 2-20 μm; b) the thickness of the solid electrolyte layer is 0.5-5 μm; c) The bulk density of the solid electrolyte layer is 1-1.2 g / cm 3 .

12. The diaphragm according to claim 10 or 11, wherein When the ratio of the thickness of the solid electrolyte layer to the thickness of the separator is ≤20%, the separator satisfies one of the following conditions: a) the thermal shrinkage of the diaphragm at 150° C. is ≤3%; b) the permeability increment of the diaphragm is 10-30s / 100cc; c) The electrochemical stability window of the separator is ≥5.1V.

13. The diaphragm according to any one of claims 10 to 12, wherein: The separator further includes an electrolyte filled in pores of the solid electrolyte layer.

14. A battery, wherein: The battery comprises the solid electrolyte according to any one of claims 1 to 5; or The battery comprises a solid electrolyte prepared by the preparation method according to any one of claims 6 to 9; or The battery comprises the separator according to any one of claims 10 to 13.

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