Preparation method and application of modified oxide solid electrolyte material

Abstract

This application discloses a preparation method and application of a modified oxide solid electrolyte material. The preparation method comprises the following steps: uniformly blending ferroelectric ceramic precursor particles, an oxide solid electrolyte, and a sintering aid to obtain a sintered precursor; and sintering the sintered precursor at a high temperature using Joule heat rapid sintering to obtain a modified oxide solid electrolyte material. The ferroelectric ceramic precursor particles comprise a first component and a second component, wherein the first component is a carbonate or oxide of a metal M, wherein the metal M is Ba, Sr, La, or Ca; and the second component is an oxide of a metal N, wherein the metal N is Ti or Nb. The preparation method disclosed in this application can produce a modified oxide solid electrolyte material with excellent electrochemical properties, improve the ionic conductivity and ion transference number of the composite solid electrolyte, and enhance the discharge capacity, cycle stability, and other properties of solid-state batteries.

Description

Technical Field

[0001] The present application belongs to the technical field of secondary battery material preparation, and specifically relates to a preparation method of a modified oxide solid electrolyte material and its application. Background Art

[0002] Oxide solid electrolytes are an important type of battery material that can achieve rapid conduction of lithium or sodium ions within them and can be used in energy storage devices such as solid-state lithium / sodium secondary batteries. Compared with traditional liquid electrolytes, oxide solid electrolytes have higher thermal stability and safety, can work stably at high temperatures, and have good mechanical strength and electrochemical stability. Its room temperature ionic conductivity is usually around 10 -4 S / cm and above, which can meet the needs of high-performance batteries.

[0003] However, there are still some problems in the specific application of oxide solid electrolytes. For example, the commonly used lithium lanthanum zirconium oxide (Li7La3Zr2O 12 , LLZO) and sodium zirconium silicon phosphorus oxide (Na3Zr2Si2PO 12 , NZSP) as an example, which are inorganic lithium fast ion conductors and sodium fast ion conductors respectively. Among them, the surface of lithium lanthanum zirconium oxide material easily reacts with water and carbon dioxide in the air to form a Li2CO3 passivation layer with poor ion conductivity, which inhibits the rapid lithium ion exchange and transfer between organic phase and inorganic phase, and inorganic phase and inorganic phase, and also reduces the electrochemical stability of the composite solid electrolyte; when sodium zirconium silicon phosphorus oxide material is used in high energy density sodium metal battery, direct contact with the metal sodium negative electrode will react in situ on the surface of sodium zirconium silicon phosphorus oxide to form sodium silicate (such as Na2SiO3, Na2Si2O5, etc.), which has poor room temperature ionic conductivity, resulting in high interfacial impedance and deterioration of electrolyte performance. At present, inorganic materials with more stable properties are generally used to coat the surface of oxide solid electrolytes to effectively inhibit or alleviate their surface side reactions. Commonly used inorganic coating materials include aluminum oxide, silicon dioxide, titanium dioxide, etc., but these materials have a single function. That is, although they provide good coating protection effect, they have little effect on improving the performance of oxide solid electrolytes.

[0004] In addition, the currently commonly used coating method is mainly the high-temperature sintering method. On the one hand, the sintering time is relatively long, generally more than several hours, which easily causes the coating layer particles to grow too large, which is not conducive to the formation of a uniform and dense coating layer; on the other hand, long-term high-temperature insulation can easily cause the coating layer elements to diffuse into the core solid electrolyte, resulting in doping, destroying the rapid transmission path of lithium / sodium ions, and causing the ionic conductivity of the solid electrolyte to decrease. Summary of the Invention

[0005] In view of this, it is necessary for the present application to provide a method for preparing a modified oxide solid electrolyte material, by which a modified oxide solid electrolyte material can be prepared with excellent electrochemical properties.

[0006] In order to achieve the above objectives, this application adopts the following technical solutions:

[0007] One aspect of the present application provides a method for preparing a modified oxide solid electrolyte material, comprising the following steps:

[0008] uniformly blending ferroelectric ceramic precursor particles, oxide solid electrolyte and sintering aid to obtain a sintering precursor;

[0009] The sintering precursor is subjected to high-temperature sintering by Joule heat rapid sintering to obtain a modified oxide solid electrolyte material;

[0010] The ferroelectric ceramic precursor particles include a first component and a second component. The first component is a carbonate or oxide of metal M, and the metal M is Ba, Sr, La or Ca; the second component is an oxide of metal N, and the metal N is Ti or Nb.

[0011] Another aspect of the present application provides the use of the modified oxide solid electrolyte material prepared by the preparation method described above in the preparation of a composite solid electrolyte or a solid-state battery.

[0012] Another aspect of the present application provides a composite solid electrolyte, which includes an electrolyte salt and an organic phase or an inorganic phase, wherein the inorganic phase is a modified oxide solid electrolyte material prepared by the preparation method described above.

[0013] Another aspect of the present application provides a solid-state battery comprising the composite solid-state electrolyte described above.

[0014] Beneficial effects of this application:

[0015] This application uses an oxide solid electrolyte material as the core and a ferroelectric ceramic material as the coating layer, which not only improves the surface stability of the oxide solid electrolyte material and avoids the formation of by-products; at the same time, the spontaneous polarization effect of the ferroelectric ceramic material can also construct an internal electric field on the surface of the oxide solid electrolyte, promote the dissociation of lithium / sodium salts on the surface and the orderly arrangement and directional migration of lithium / sodium ions at the interface, and destroy the reverse charge layer with a shielding effect on the surface of the filler, which can improve the ionic conductivity and ion migration number of the composite solid electrolyte, and further enhance the discharge capacity, cycle stability and other performance of the solid-state battery.

[0016] This application adopts an in-situ high-temperature sintering process. By using Joule heat rapid sintering technology and coordinating with sintering aids, the coating layer of the modified oxide solid electrolyte material obtained is uniform, and the core and coating layer materials are of high purity. This not only improves the electrochemical properties of the modified oxide solid electrolyte material, but also the process has the significant advantages of simple operation, high production efficiency and low energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Li used in Example 1 6.4 La3Zr 1.4 Ta 0.6 O 12 SEM images of particles;

[0018] Figure 2 Li prepared in Example 1 6.4 La3Zr 1.4 Ta 0.6 O 12 @SEM photo of BaTiO3+KNbO3;

[0019] Figure 3 Li prepared in Example 1 6.4 La3Zr 1.4 Ta 0.6 O 12 @XRD spectrum of BaTiO3+KNbO3;

[0020] Figure 4 Li prepared in Comparative Example 1 6.4 La3Zr 1.4 Ta 0.6 O 12 @SEM photo of BaTiO3+KNbO3;

[0021] Figure 5 Li prepared in Comparative Example 2 6.4 La3Zr 1.4 Ta 0.6 O 12 @SEM photo of BaTiO3;

[0022] Figure 6 Comparison of the 0.5C constant current charge-discharge cycle performance of the solid-state battery prepared in Example 1 and the solid-state batteries prepared in Comparative Examples 1, 2, and 3 at 25°C;

[0023] Figure 7 Comparison of electrochemical impedance spectra of the solid-state battery prepared in Example 1 and the solid-state batteries prepared in Comparative Examples 1, 2, and 3 after 200 cycles at 0.5C and 25°C;

[0024] Figure 8Comparison of the 0.5C constant current charge and discharge cycle performance of the solid-state battery prepared in Example 2 and the solid-state battery prepared in Comparative Example 4 at 60°C. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the embodiments of the present application. The technical solutions in the embodiments described below are exemplary and are only possible technical implementations of the present application, not all possible implementations. Those skilled in the art can fully combine the embodiments of the present application to obtain other embodiments without creative work, and these embodiments are also within the scope of protection of the present application.

[0026] In the first aspect, the present application discloses a method for preparing a modified oxide solid electrolyte material. In response to the problems existing in the practical application of oxide solid electrolyte materials, the present application proposes a method for preparing a coated modified oxide solid electrolyte material by in-situ high-temperature sintering:

[0027] From the perspective of the product obtained, the product obtained by the preparation method in this application is an oxide solid electrolyte material coated with a ferroelectric ceramic material. The ferroelectric ceramic material has a spontaneous polarization characteristic. The built-in electric field generated by its spontaneous polarization can regulate the electric field distribution on the interface between it and the polymer phase, further promoting the dissociation of lithium / sodium salts on the one hand, and on the other hand, forming a fast and continuous lithium / sodium ion transmission path on the surface, which can significantly improve the ionic conductivity. Therefore, the oxide solid electrolyte material coated with a ferroelectric ceramic material formed in this application helps to improve surface stability and avoid the formation of a by-product layer on the one hand, and its spontaneous polarization effect can also construct an internal electric field on the surface of the inorganic filler, promoting the dissociation of lithium / sodium salts on the surface and the orderly arrangement and directional migration of lithium / sodium ions at the interface, and destroying the countercharge layer with a shielding effect. When applied to an organic-inorganic composite solid electrolyte, it helps to achieve further enhancement of the ionic conductivity, ion migration number and other properties of the composite solid electrolyte and further improvement of the discharge capacity, cycle stability and other properties of the solid-state lithium / sodium secondary battery.

[0028] In terms of the preparation process, the present application adopts an in-situ high-temperature sintering method, introduces a sintering aid into the sintering precursor, and cooperates with a Joule heat high-temperature rapid sintering process, wherein a ferroelectric ceramic material with a low melting point is introduced as a sintering aid (melting point is 850-1250°C), which can be melted at the sintering temperature to produce a liquid phase, thereby accelerating the particle rearrangement and mass transfer process, and inhibiting grain growth, thereby improving the uniformity of sintering and coating. In addition, the use of Joule heat high-temperature rapid sintering method for rapid sintering and coating can complete the in-situ synthesis and coating of the coating material in an ultra-short time of a few seconds to a few minutes, avoiding the problem of excessive growth of grains in traditional high-temperature sintering (several hours) leading to uneven coating, and the problem of core doping caused by diffusion of elements in the coating layer due to long-term heat preservation, thereby improving the purity of the coating and the core; and the one-step in-situ sintering and coating method adopted in the present application also saves costs, simplifies operations, and reduces sintering temperature and energy consumption.

[0029] The method for preparing the modified oxide solid electrolyte material described in this application comprises the following steps:

[0030] S1. Evenly blending ferroelectric ceramic precursor particles, oxide solid electrolyte and sintering aid to obtain a sintering precursor.

[0031] During the specific preparation, ferroelectric ceramic precursor particles, oxide solid electrolyte and sintering aid are added to a certain amount of dispersion medium, mixed thoroughly, and then the dispersion medium is removed (for example, by evaporation) to obtain a sintered precursor.

[0032] In the present application, the ferroelectric ceramic precursor particles refer to the precursor form of the target ferroelectric ceramic material in the coating layer. In the present application, the ferroelectric ceramic precursor particles include a first component and a second component, wherein the first component is a carbonate or oxide of a metal M, wherein the metal M is Ba, Sr, La, or Ca; and the second component is an oxide of a metal N, wherein the metal N is Ti or Nb. The ferroelectric ceramic material can be formed by sintering the first and second components. In some specific embodiments of the present application, the first component is one of BaCO3, SrCO3, La2O3, and CaCO3; and the second component is TiO2 or Nb2O5, but is not limited thereto.

[0033] Among them, the ratio of the first component and the second component can be set by technicians in this field according to the composition of the target ferroelectric ceramic material in the coating layer. Those skilled in the art have such ability. In some specific embodiments of the present application, the composition of the ferroelectric ceramic material in the coating layer is one of barium titanate (BaTiO3), strontium titanate (SrTiO3), lanthanum titanate (La2Ti2O7), strontium niobate (Sr2Nb2O7), and calcium niobate (Ca2Nb2O7), but is not limited to this.

[0034] In some specific embodiments of the present application, for the target ferroelectric ceramic material being barium titanate, the ferroelectric ceramic precursor particles can be barium carbonate (BaCO3) and titanium dioxide (TiO2), wherein the molar ratio of barium carbonate to titanium dioxide is 1:1.

[0035] In some other specific embodiments of the present application, for the target ferroelectric ceramic material being strontium titanate, the ferroelectric ceramic precursor particles can be strontium carbonate (SrCO3) and titanium dioxide (TiO2), wherein the molar ratio of strontium carbonate to titanium dioxide is 1:1.

[0036] In some other specific embodiments of the present application, for the target ferroelectric ceramic material being lanthanum titanate, the ferroelectric ceramic precursor particles can be lanthanum trioxide (La2O3) and titanium dioxide (TiO2), wherein the molar ratio of lanthanum trioxide to titanium dioxide is 1:2.

[0037] In some other specific embodiments of the present application, for the target ferroelectric ceramic material being strontium niobate, the ferroelectric ceramic precursor particles can be strontium carbonate (SrCO3) and niobium pentoxide (Nb2O5), wherein the molar ratio of strontium carbonate to niobium pentoxide is 2:1.

[0038] In some other specific embodiments of the present application, for the target ferroelectric ceramic material being calcium niobate, the ferroelectric ceramic precursor particles can be calcium carbonate (CaCO3) and niobium pentoxide (Nb2O5), wherein the molar ratio of calcium carbonate to niobium pentoxide is 2:1.

[0039] In the present application, the oxide solid electrolyte is a type of electrolyte material composed of oxides and non-metallic ions (usually anions), and its main types include garnet type, NASICON type, perovskite type, etc. In the present application, there are no special requirements for the types of the oxide solid electrolyte, and common types in the art can be used. In some specific embodiments of the present application, the oxide solid electrolyte can be lithium lanthanum zirconium oxide (Li7La 12 3Zr2O 7-x ,LLZO), tantalum-doped lithium lanthanum zirconium oxide (Li 2-x La3Zr x Ta 12 O 12 ,0 < x ≤ 1, LLZTO), sodium zirconium silicon phosphorus oxide (Na3Zr2Si2PO 12 ,NZSP), but not limited thereto.

[0040] In the present application, the sintering aid is a type of ferroelectric ceramic material with a relatively low melting point (melting point between 850 and 1250 °C), preferably potassium niobate (KNbO3), bismuth ferrite (BiFeO3), bismuth titanate (Bi4Ti3O12 ). Introducing a ferroelectric ceramic material with a low melting point as a sintering aid allows it to melt at the sintering temperature to produce a liquid phase, thereby accelerating particle rearrangement and mass transfer, inhibiting grain growth, and effectively improving sintering and coating uniformity. Furthermore, the sintering aid itself is a ferroelectric ceramic material with spontaneous polarization properties, which also contributes to the control of the filler surface electric field.

[0041] It should be noted that due to the short Joule heat sintering time and limited diffusion rate, to ensure a sufficient sintering reaction and a uniform coating, the particle sizes of the ferroelectric ceramic precursor particles and sintering aids must meet certain requirements. The ferroelectric ceramic precursor particles must be less than 500 nm, and the sintering aid must be less than 500 nm. Furthermore, to ensure the resulting material is well suited for use in organic-inorganic composite solid electrolytes, the oxide solid electrolyte particle size must be between 2 and 15 μm. If the raw material particle size does not meet these requirements, grinding and screening are required.

[0042] Furthermore, in the sintered precursor, the ratio of each component is not particularly limited and can be determined by those skilled in the art according to methods or experiments known in the art. In some specific implementation cases, the mass percentage of the oxide solid electrolyte is 80.0% to 99.8%, for example, any value among 80%, 82%, 85%, 88%, 90%, 95%, and 99.8%, based on the mass of the sintered precursor. The mass ratio of the ferroelectric ceramic precursor particles to the oxide solid electrolyte is (0.2 to 25):100. For example, the ratio can be any of 0.2:100, 1:100, 5:100, 10:100, 15:100, 20:100, 22:100, and 25:100; based on the ferroelectric ceramic precursor particles, the mass percentage of the sintering aid is 0.2% to 6%, for example, it can be any of 0.2%, 0.3%, 0.4%, 0.5%, 0.8%, 1%, 1.2%, 1.4%, 1.8%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, and 6%.

[0043] Furthermore, the dispersion medium is preferably inert toward the ferroelectric ceramic precursor particles, oxide solid electrolyte, and sintering aid, and is capable of achieving excellent dispersion of these raw materials. Inertness here means that the dispersion medium does not react with the raw materials. For example, it can be water or an alcoholic organic reagent, such as anhydrous ethanol or isopropyl alcohol. In some specific embodiments of the present application, anhydrous ethanol is preferably used.

[0044] S2. Using Joule heat rapid sintering to sinter the sintering precursor at high temperature to obtain a modified oxide solid electrolyte material.

[0045] In this application, the Joule heat rapid sintering method utilizes the Joule heat generated by an electric current passing through a conductive material (such as carbon felt or graphite) to rapidly heat the material to a high temperature (up to 1000°C to 3000°C) within a very short period of time (typically a few seconds to tens of seconds), achieving rapid sintering of the material. This method offers advantages such as rapid heating, short sintering time, low energy consumption, simple equipment structure, and ease of maintenance.

[0046] In this application, by adopting the Joule heat rapid sintering method for rapid high-temperature sintering and coating, the in-situ synthesis and coating of the coating layer material can be completed in an ultra-short time of seconds to minutes, avoiding the problems of excessive grain growth leading to uneven coating layer and long-term insulation of the coating layer element diffusion leading to core doping, thereby improving the purity of the coating layer and the core and improving the electrochemical properties of the material.

[0047] Among them, the specific sintering conditions are selected according to the difference between the coating material and the core material. Specifically, the sintering temperature is set to be higher than the melting point of the sintering aid and lower than the melting point of the sintered ferroelectric ceramic raw material particles and the fired ferroelectric ceramic material, so that at the sintering temperature, the sintering aid can melt into a liquid phase, thereby accelerating the particle rearrangement and mass transfer process, inhibiting grain growth, and improving the uniformity of the sintering coating. In some specific embodiments of the present application, the sintering temperature of the Joule heat rapid sintering is 1000-1400°C, for example, it can be any temperature among 1000°C, 1050°C, 1100°C, 1150°C, 1200°C, 1250°C, 1300°C, and 1350°C; the heating time is 3-15s, for example, it can be any time among 3s, 4s, 5s, 6s, 7s, 8s, 9s, 10s, 11s, 12s, 13s, 14s, and 15s; the sintering time is 3-100s, for example, it can be any time among 3s, 5s, 10s, 15s, 20s, 30s, 40s, 50s, 60s, 70s, 80s, 90s, and 100s; the sintering atmosphere is air, nitrogen, or argon.

[0048] The second aspect of the present application discloses the use of the modified oxide solid electrolyte material prepared by the preparation method described above in the preparation of a composite solid electrolyte or a solid-state battery.

[0049] The third aspect of the present application discloses a composite solid electrolyte, which includes an electrolyte salt, an organic phase and an inorganic phase. The inorganic phase is a modified oxide solid electrolyte material prepared by the preparation method described above.

[0050] The fourth aspect of the present application discloses a solid-state battery, which contains the composite solid-state electrolyte described above.

[0051] In some specific embodiments of the present application, the inorganic phase accounts for a mass ratio of 0.5 wt% to 50 wt% of the total mass of the composite solid electrolyte. This is because the amount of the inorganic phase added should not be too low, otherwise it will be difficult to form a continuous conductive path; at the same time, the amount added should not be too high, otherwise it will easily agglomerate, which is not conducive to the uniform dispersion of the inorganic phase and is also detrimental to ionic conductivity. Preferably, the mass ratio of the inorganic phase in the composite solid electrolyte is 5 wt% to 20 wt%.

[0052] Furthermore, the organic phase in the composite solid electrolyte described in this application can be a conventional choice in the art, without particular limitation, for example, it can be selected from at least one of polyethylene oxide (PEO), polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), and polypropylene carbonate (PPC). It is understood that the types of organic phases in the composite solid electrolyte described in this application are not limited to the above-mentioned ones, and any organic phase material that can be used in secondary batteries can be used, and no further description is given here.

[0053] Furthermore, the electrolyte salt described in this application can be a conventional choice in the art, without particular limitation, such as lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium hexafluorophosphate (LiPF6), lithium trifluoromethanesulfonate (LiCF3SO3), sodium bis(trifluoromethanesulfonyl)imide (NaTFSI), sodium bis(fluorosulfonyl)imide (NaFSI), sodium hexafluorophosphate (NaPF6), sodium trifluoromethanesulfonate (NaCF3SO3). It is understood that the types of electrolyte salts in this application are not limited to the above-mentioned ones, and any electrolyte salt that can be used in secondary batteries can be used, and they will not be described one by one here.

[0054] In addition, the concentration of the electrolyte salt in the organic phase is not particularly limited and can be added according to conventional concentrations in the art and can be adjusted as needed. Preferably, the mass ratio of the electrolyte salt to the organic phase is between (1 to 2): (1 to 10). In some specific embodiments of the present application, the molar ratio of the electrolyte salt to the organic phase is between 1: (1 to 4).

[0055] It is understandable that the composite solid electrolyte is prepared using conventional preparation methods in the art and can be adjusted as needed, such as solution casting, doctor blade coating, casting, heating curing, ultraviolet radiation curing, etc., which will not be described here one by one.

[0056] The solid-state battery described in this application is not particularly limited. It can be a lithium solid-state battery or a sodium solid-state battery. The selection of its positive and negative electrodes is selected according to the different types of solid-state batteries. For example, when the battery is a lithium solid-state battery, its positive electrode active material can be selected from at least one of lithium iron phosphate, lithium iron manganese phosphate, lithium cobalt oxide, lithium manganate, ternary nickel cobalt manganese, and ternary nickel cobalt aluminum, and its negative electrode active material can be selected from at least one of graphite, hard carbon, silicon carbon, lithium titanate, metallic lithium, and metallic lithium alloy. When the battery is a sodium solid-state battery, its positive electrode active material can be selected from at least one of sodium vanadium phosphate, sodium vanadium fluorophosphate, sodium iron phosphate, ternary nickel iron manganese, and Prussian blue analogs, and its negative electrode active material can be selected from at least one of metallic sodium, hard carbon, graphite, and sodium titanate. It should be noted that the specific preparation and composition of the positive and negative electrodes in this application are not particularly limited, and conventional selections in the art are all acceptable.

[0057] It can be understood that the preparation conditions of the solid-state battery in this application are similar to those of conventional solid-state batteries. Preferably, the preparation and assembly are carried out under the condition that the water and oxygen content are lower than 0.1 ppm, which is not specifically limited here.

[0058] The following are specific embodiments of the present application. It should be noted that the following specific embodiments are only for illustrative purposes and do not limit the scope of the present application in any way.

[0059] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0060] In addition, unless otherwise specified, methods without specific conditions or steps are conventional methods, and the reagents and materials used are all commercially available.

[0061] Example 1

[0062] This embodiment provides a method for preparing a modified oxide solid electrolyte material and the application of the material in composite solid electrolytes and solid-state batteries.

[0063] 1. Modified oxide solid electrolyte material Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Preparation of @BaTiO3+KNbO3

[0064] Preparation of sintering precursor: The first component of the ferroelectric ceramic BaTiO3 precursor particles is BaCO3, and the second component is TiO2, with a stoichiometric ratio of 1:1. 0.197g BaCO3 particles (ground and sieved <500nm), 0.080g TiO2 particles (raw material 40nm), 0.006g sintering aid KNbO3 particles (ground and sieved <500nm) and 1.262g Li 6.4 La3Zr 1.4 Ta 0.6 O 12 The particles (ground and sieved to 2-15 μm) were added to a beaker containing 20 mL of anhydrous ethanol and magnetically stirred at 30 °C for 6 h. They were then dried at 60 °C for 24 h to completely evaporate the anhydrous ethanol. The remaining material was ground in an agate mortar to obtain a sintering precursor.

[0065] Joule heat high temperature rapid sintering: Place the sintering precursor between two layers of carbon paper in the Joule heat rapid sintering equipment, control the sintering temperature to 1200℃, the heating time to 5s, the sintering time to 20s, and the sintering atmosphere to air. After natural cooling, grind to obtain the modified oxide solid electrolyte material Li 6.4 La3Zr 1.4 Ta 0.6 O 12 @BaTiO3+KNbO3.

[0066] 2. Preparation of composite solid electrolyte

[0067] The composite solid electrolyte was prepared by solution casting method: the electrolyte salt LiTFSI and the organic phase PVDF were dissolved in an appropriate amount of N,N-dimethylformamide in a mass ratio of 1:2, and after stirring and fully dissolved, the inorganic phase (Li 6.4 La3Zr 1.4 Ta 0.6 O 12 @BaTiO3+KNbO3), where the inorganic phase accounts for 15wt% of the total mass of the organic phase, inorganic phase, and electrolyte salt. After further stirring, the mixed solution is cast onto a polytetrafluoroethylene plate and vacuum-dried at 60°C for 24 hours. After the N,N-dimethylformamide is fully evaporated, a composite solid electrolyte film with a thickness of approximately 50μm is obtained.

[0068] 3. Preparation of solid-state batteries

[0069] In an argon-protected glove box, the composite solid electrolyte film was placed on the ternary nickel-cobalt-manganese cathode (LiNi 0.8 Co 0.1 Mn 0.1 O2, NCM811) and lithium metal negative electrode (Li), and a small amount (3 μL / cm 2) carbonate-based electrolyte (1MLiTFSI / EC+DEC (mass ratio 1:1)) was used to infiltrate the interior of the positive electrode and form the necessary ion-conducting network. After being encapsulated in a 2032-type button battery shell, a Li||NCM811 solid-state battery was obtained.

[0070] Example 2

[0071] This embodiment provides a method for preparing another modified oxide solid electrolyte material and the application of the material in composite solid electrolytes and solid-state batteries.

[0072] 1. Modified oxide solid electrolyte material Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Preparation of @SrTiO3+KNbO3

[0073] Preparation of sintering precursor: The first component of the ferroelectric ceramic SrTiO3 precursor particles is SrCO3, and the second component is TiO2, with a stoichiometric ratio of 1:1. 0.148g of SrCO3 particles (ground and sieved <500nm), 0.080g of TiO2 particles (raw material 40nm), 0.007g of sintering aid KNbO3 particles (ground and sieved <500nm) and 2.052g of Li 6.4 La3Zr 1.4 Ta 0.6 O 12 The particles (ground and sieved to 2-15 μm) were added to a beaker containing 20 mL of anhydrous ethanol and magnetically stirred at 30 °C for 6 h. They were then dried at 60 °C for 24 h to completely evaporate the anhydrous ethanol. The remaining material was ground in an agate mortar to obtain a sintering precursor.

[0074] Joule heat high temperature rapid sintering: The sintering precursor is placed between two layers of carbon paper in the Joule heat rapid sintering equipment, the sintering temperature is controlled to 1400℃, the heating time is 10s, the sintering time is 40s, and the sintering atmosphere is nitrogen. After natural cooling, it is ground to obtain the modified oxide solid electrolyte material Li 6.4 La3Zr 1.4 Ta 0.6 O 12 @SrTiO3+KNbO3.

[0075] 2. Preparation of composite solid electrolyte

[0076] The composite solid electrolyte was prepared by solution casting method: the electrolyte salt LiTFSI and the organic phase PEO were dissolved in an appropriate amount of N,N-dimethylformamide in a mass ratio of 1:1, and after stirring and fully dissolving, the inorganic phase (Li 6.4 La3Zr 1.4 Ta0.6 O 12 @SrTiO3+KNbO3), where the inorganic phase accounts for 20wt% of the total mass of the organic phase, inorganic phase, and electrolyte salt. After further stirring, the mixed solution is cast onto a polytetrafluoroethylene plate and vacuum-dried at 60°C for 24 hours. After the N,N-dimethylformamide is fully evaporated, a composite solid electrolyte film with a thickness of approximately 60μm is obtained.

[0077] 3. Preparation of solid-state batteries

[0078] In an argon-protected glove box, the composite solid electrolyte film was placed between a lithium iron phosphate (LiFePO4) cathode and a lithium metal anode (Li). A trace amount (2 μL / cm 2 ) carbonate-based electrolyte (1M LiPF6 / EC+DEC (mass ratio 1:1)) is used to infiltrate the interior of the positive electrode and form the necessary ion-conducting network. After being encapsulated in a 2032-type button battery shell, a Li||LiFePO4 solid-state battery is obtained.

[0079] Example 3

[0080] This embodiment provides a method for preparing another modified oxide solid electrolyte material and the application of the material in composite solid electrolytes and solid-state batteries.

[0081] 1. Modified oxide solid electrolyte material Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Preparation of @La2Ti2O7+KNbO3

[0082] Preparation of sintering precursor: The first component of the ferroelectric ceramic La2Ti2O7 precursor particles is La2O3, and the second component is TiO2, with a stoichiometric ratio of 1:2. 0.326g La2O3 particles (raw material 50nm), 0.160g TiO2 particles (raw material 40nm), 0.0005g sintering aid KNbO3 particles (grinded and sieved <500nm) and 9.234g Li 6.4 La3Zr 1.4 Ta 0.6 O 12 The particles (ground and sieved to 2-15 μm) were added to a beaker containing 40 mL of anhydrous ethanol and magnetically stirred at 30 °C for 6 h. They were then dried at 60 °C for 24 h to completely evaporate the anhydrous ethanol. The remaining material was ground in an agate mortar to obtain a sintering precursor.

[0083] Joule heat high temperature rapid sintering: The sintering precursor is placed between two layers of carbon paper in a Joule heat rapid sintering device, the sintering temperature is controlled to be 1300℃, the heating time is 5s, the sintering time is 30s, and the sintering atmosphere is air. After natural cooling, the modified oxide solid electrolyte material Li is obtained by grinding. 6.4 La3Zr 1.4 Ta 0.6 O 12 @La2Ti2O7+KNbO3.

[0084] 2. Preparation of composite solid electrolyte

[0085] The composite solid electrolyte was prepared by solution casting method: the electrolyte salt LiTFSI and the organic phase PVDF and PAN were dissolved in an appropriate amount of N,N-dimethylformamide in a mass ratio of 5:9:1, and after stirring and fully dissolving, the inorganic phase (Li 6.4 La3Zr 1.4 Ta 0.6 O 12 @La2Ti2O7+KNbO3), where the inorganic phase accounts for 10wt% of the total mass of the organic phase, inorganic phase, and electrolyte salt. After further stirring, the mixed solution is cast onto a polytetrafluoroethylene plate and vacuum-dried at 60°C for 24 hours. After the N,N-dimethylformamide is fully evaporated, a composite solid electrolyte film with a thickness of approximately 40μm is obtained.

[0086] 3. Preparation of solid-state batteries

[0087] In an argon-protected glove box, the composite solid electrolyte film was placed on the ternary nickel-cobalt-manganese cathode (LiNi 0.8 Co 0.1 Mn 0.1 O2, NCM811) and lithium metal negative electrode (Li), and a small amount (3 μL / cm 2 ) carbonate-based electrolyte (1MLiTFSI / EC+DEC (mass ratio 1:1)) was used to infiltrate the interior of the positive electrode and form the necessary ion-conducting network. After being encapsulated in a 2032-type button battery shell, a Li||NCM811 solid-state battery was obtained.

[0088] Example 4

[0089] This embodiment provides a method for preparing another modified oxide solid electrolyte material and the application of the material in composite solid electrolytes and solid-state batteries.

[0090] 1. Modified oxide solid electrolyte material Li 6.4 La3Zr 1.4 Ta 0.6 O 12Preparation of @Sr2Nb2O7+KNbO3

[0091] Preparation of sintering precursor: The first component of the ferroelectric ceramic Sr2Nb2O7 precursor particles is SrCO3, and the second component is Nb2O5, with a stoichiometric ratio of 2:1. 0.591g SrCO3 particles (ground and sieved <500nm), 0.532g Nb2O5 particles (ground and sieved <500nm), 0.0002g sintering aid KNbO3 particles (ground and sieved <500nm) and 4.492g Li 6.4 La3Zr 1.4 Ta 0.6 O 12 The particles (ground and sieved to 2-15 μm) were added to a beaker containing 30 mL of anhydrous ethanol and magnetically stirred at 30 °C for 6 h. They were then dried at 60 °C for 24 h to completely evaporate the anhydrous ethanol. The remaining material was ground in an agate mortar to obtain a sintering precursor.

[0092] Joule heat high temperature rapid sintering: The sintering precursor is placed between two layers of carbon paper in a Joule heat rapid sintering device, the sintering temperature is controlled to be 1250℃, the heating time is 5s, the sintering time is 100s, and the sintering atmosphere is argon. After natural cooling, the modified oxide solid electrolyte material Li is obtained by grinding. 6.4 La3Zr 1.4 Ta 0.6 O 12 @Sr2Nb2O7+KNbO3.

[0093] 2. Preparation of composite solid electrolyte

[0094] The composite solid electrolyte was prepared by solution casting method: the electrolyte salt LiTFSI and the organic phase PVDF were dissolved in an appropriate amount of N,N-dimethylformamide in a mass ratio of 1:2, and after stirring and fully dissolved, the inorganic phase (Li 6.4 La3Zr 1.4 Ta 0.6 O 12 @Sr2Nb2O7+KNbO3), where the inorganic phase accounts for 15wt% of the total mass of the organic phase, inorganic phase, and electrolyte salt. After further stirring, the mixed solution is cast onto a polytetrafluoroethylene plate and vacuum-dried at 60°C for 24 hours. After the N,N-dimethylformamide is fully evaporated, a composite solid electrolyte film with a thickness of approximately 50μm is obtained.

[0095] 3. Preparation of solid-state batteries

[0096] In an argon-protected glove box, the composite solid electrolyte film was placed between a lithium iron phosphate (LiFePO4) cathode and a lithium metal anode (Li). A trace amount (3 μL / cm2 ) carbonate-based electrolyte (1M LiPF6 / EC+DEC (mass ratio 1:1)) is used to infiltrate the interior of the positive electrode and form the necessary ion-conducting network. After being encapsulated in a 2032-type button battery shell, a Li||LiFePO4 solid-state battery is obtained.

[0097] Example 5

[0098] This embodiment provides a method for preparing another modified oxide solid electrolyte material and the application of the material in composite solid electrolytes and solid-state batteries.

[0099] 1. Modified oxide solid electrolyte material Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Preparation of @Ca2Nb2O7+KNbO3

[0100] Preparation of sintering precursor: The first component of the ferroelectric ceramic Ca2Nb2O7 precursor particles is CaCO3, and the second component is Nb2O5, with a stoichiometric ratio of 2:1. 0.200g of CaCO3 particles (raw material 50nm), 0.266g of Nb2O5 particles (ground and sieved <500nm), 0.028g of sintering aid KNbO3 particles (ground and sieved <500nm) and 2.641g of Li 6.4 La3Zr 1.4 Ta 0.6 O 12 The particles (ground and sieved to 2-15 μm) were added to a beaker containing 20 mL of anhydrous ethanol and magnetically stirred at 30 °C for 6 h. They were then dried at 60 °C for 24 h to completely evaporate the anhydrous ethanol. The remaining material was ground in an agate mortar to obtain a sintering precursor.

[0101] Joule heat high temperature rapid sintering: The sintering precursor is placed between two layers of carbon paper in the Joule heat rapid sintering equipment, the sintering temperature is controlled to 1200℃, the heating time is 3s, the sintering time is 40s, and the sintering atmosphere is nitrogen. After natural cooling, it is ground to obtain the modified oxide solid electrolyte material Li 6.4 La3Zr 1.4 Ta 0.6 O 12 @Ca2Nb2O7+KNbO3.

[0102] 2. Preparation of composite solid electrolyte

[0103] The composite solid electrolyte was prepared by solution casting method: the electrolyte salt LiTFSI and the organic phase PVDF were dissolved in an appropriate amount of N,N-dimethylformamide in a mass ratio of 1:2, and after stirring and fully dissolved, the inorganic phase (Li 6.4La3Zr 1.4 Ta 0.6 O 12 @Ca2Nb2O7+KNbO3), where the inorganic phase accounts for 15wt% of the total mass of the organic phase, inorganic phase, and electrolyte salt. After further stirring, the mixed solution is cast onto a polytetrafluoroethylene plate and vacuum-dried at 60°C for 24 hours. After the N,N-dimethylformamide is fully evaporated, a composite solid electrolyte film with a thickness of approximately 50μm is obtained.

[0104] 3. Preparation of solid-state batteries

[0105] In an argon-protected glove box, the composite solid electrolyte film was placed between a lithium iron phosphate (LiFePO4) cathode and a lithium metal anode (Li). A trace amount (3 μL / cm 2 ) carbonate-based electrolyte (1M LiPF6 / EC+DEC (mass ratio 1:1)) is used to infiltrate the interior of the positive electrode and form the necessary ion-conducting network. After being encapsulated in a 2032-type button battery shell, a Li||LiFePO4 solid-state battery is obtained.

[0106] Example 6

[0107] This embodiment provides a method for preparing another modified oxide solid electrolyte material and the application of the material in composite solid electrolytes and solid-state batteries.

[0108] 1. Modified oxide solid electrolyte material Li 6.4 La3Zr 1.4 Ta 0.6 O 12 @BaTiO3+Bi4Ti3O 12 Preparation

[0109] Preparation of sintering precursor: The first component of the ferroelectric ceramic BaTiO3 precursor particles is BaCO3, and the second component is TiO2, with a stoichiometric ratio of 1:1. 0.197g BaCO3 particles (grinded and sieved <500nm), 0.080g TiO2 particles (raw material 40nm), 0.014g sintering aid Bi4Ti3O 12 Particles (grinded and sieved <500nm) and 13.573g Li 6.4 La3Zr 1.4 Ta 0.6 O 12 The particles (ground and sieved to 2-15 μm) were added to a beaker containing 40 mL of anhydrous ethanol and magnetically stirred at 30 °C for 6 h. They were then dried at 60 °C for 24 h to completely evaporate the anhydrous ethanol. The remaining material was ground in an agate mortar to obtain a sintering precursor.

[0110] Joule heat high temperature rapid sintering: The sintering precursor is placed between two layers of carbon paper in the Joule heat rapid sintering equipment, the sintering temperature is controlled to be 1250℃, the heating time is 5s, the sintering time is 30s, and the sintering atmosphere is air. After natural cooling, it is ground to obtain the modified oxide solid electrolyte material Li 6.4 La3Zr 1.4 Ta 0.6 O 12 @BaTiO3+Bi4Ti3O 12 .

[0111] 2. Preparation of composite solid electrolyte

[0112] The composite solid electrolyte was prepared by solution casting method: the electrolyte salt LiTFSI and the organic phase PVDF were dissolved in an appropriate amount of N,N-dimethylformamide in a mass ratio of 1:2, and after stirring and fully dissolved, the inorganic phase (Li 6.4 La3Zr 1.4 Ta 0.6 O 12 @BaTiO3+Bi4Ti3O 12 ), wherein the inorganic phase accounts for 15 wt% of the total mass of the organic phase, inorganic phase, and electrolyte salt. After further stirring, the mixed solution is cast onto a polytetrafluoroethylene plate and vacuum-dried at 60°C for 24 hours. After the N,N-dimethylformamide is fully evaporated, a composite solid electrolyte film with a thickness of approximately 50 μm is obtained.

[0113] 3. Preparation of solid-state batteries

[0114] In an argon-protected glove box, the composite solid electrolyte film was placed on the ternary nickel-cobalt-manganese cathode (LiNi 0.8 Co 0.1 Mn 0.1 O2, NCM811) and lithium metal negative electrode (Li), and a small amount (3 μL / cm 2 ) carbonate-based electrolyte (1MLiPF6 / EC+DEC (mass ratio 1:1)) was used to infiltrate the interior of the positive electrode and form the necessary ion-conducting network. After being encapsulated in a 2032-type button battery shell, a Li||NCM811 solid-state battery was obtained.

[0115] Example 7

[0116] This embodiment provides a method for preparing another modified oxide solid electrolyte material and the application of the material in composite solid electrolytes and solid-state batteries.

[0117] 1. Modified oxide solid electrolyte material Li7La3Zr2O 12 Preparation of @BaTiO3+BiFeO3

[0118] Preparation of sintering precursor: The first component of the ferroelectric ceramic BaTiO3 precursor particles is BaCO3, and the second component is TiO2, with a stoichiometric ratio of 1:1. 0.197g BaCO3 particles (ground and sieved <500nm), 0.080g TiO2 particles (raw material 40nm), 0.003g sintering aid BiFeO3 particles (ground and sieved <500nm) and 5.263g Li7La3Zr2O 12 The particles (ground and sieved to 2-15 μm) were added to a beaker containing 30 mL of anhydrous ethanol and magnetically stirred at 30 °C for 6 h. They were then dried at 60 °C for 24 h to completely evaporate the anhydrous ethanol. The remaining material was ground in an agate mortar to obtain a sintering precursor.

[0119] Joule heat high temperature rapid sintering: The sintering precursor is placed between two layers of carbon paper in a Joule heat rapid sintering device, the sintering temperature is controlled at 1000°C, the heating time is 3s, the sintering time is 30s, and the sintering atmosphere is air. After natural cooling, it is ground to obtain the modified oxide solid electrolyte material Li7La3Zr2O 12 @BaTiO3+BiFeO3.

[0120] 2. Preparation of composite solid electrolyte

[0121] The composite solid electrolyte was prepared by solution casting: the electrolyte salt LiTFSI and the organic phase PVDF were dissolved in an appropriate amount of N,N-dimethylformamide in a mass ratio of 1:2, and after stirring and fully dissolving, the inorganic phase (Li7La3Zr2O 12 @BaTiO3+BiFeO3), where the inorganic phase accounts for 15wt% of the total mass of the organic phase, inorganic phase, and electrolyte salt. After further stirring, the mixed solution is cast onto a polytetrafluoroethylene plate and vacuum-dried at 60°C for 24 hours. After the N,N-dimethylformamide is fully evaporated, a composite solid electrolyte film with a thickness of approximately 50μm is obtained.

[0122] 3. Preparation of solid-state batteries

[0123] In an argon-protected glove box, the composite solid electrolyte film was placed between a lithium cobalt oxide positive electrode (LiCoO2, LCO) and a lithium metal negative electrode (Li). A trace amount (3 μL / cm 2 ) carbonate-based electrolyte (1M LiPF6 / EC+DEC (mass ratio 1:1)) was used to infiltrate the interior of the positive electrode and form the necessary ion-conducting network. After being encapsulated in a 2032-type button battery shell, a Li||LCO solid-state battery was obtained.

[0124] Example 8

[0125] This embodiment provides a method for preparing another modified oxide solid electrolyte material and the application of the material in composite solid electrolytes and solid-state batteries.

[0126] 1. Modified oxide solid electrolyte material Na3Zr2Si2PO 12 Preparation of @Ca2Nb2O7+KNbO3

[0127] Preparation of sintering precursor: The first component of the ferroelectric ceramic Ca2Nb2O7 precursor particles is CaCO3, and the second component is Nb2O5, with a stoichiometric ratio of 2:1. 0.200g of CaCO3 particles (raw material 50nm), 0.266g of Nb2O5 particles (ground and sieved <500nm), 0.005g of sintering aid KNbO3 particles (ground and sieved <500nm) and 4.194g of Na3Zr2Si2PO 12 The particles (ground and sieved to 2-10 μm) were added to a beaker containing 30 mL of anhydrous ethanol and magnetically stirred at 30 °C for 6 h. They were then dried at 70 °C for 24 h to completely evaporate the anhydrous ethanol. The remaining material was ground in an agate mortar to obtain a sintering precursor.

[0128] Joule heat high temperature rapid sintering: The sintering precursor is placed between two layers of carbon paper in a Joule heat rapid sintering device, the sintering temperature is controlled at 1200°C, the heating time is 10s, the sintering time is 80s, and the sintering atmosphere is argon. After natural cooling, it is ground to obtain the modified oxide solid electrolyte material Na3Zr2Si2PO 12 @Ca2Nb2O7+KNbO3.

[0129] 2. Preparation of composite solid electrolyte

[0130] The composite solid electrolyte was prepared by solution casting: the electrolyte salt NaTFSI and the organic phase PEO were dissolved in an appropriate amount of N,N-dimethylformamide in a mass ratio of 1:1, and after stirring and fully dissolving, the inorganic phase (Na3Zr2Si2PO 12 @Ca2Nb2O7+KNbO3), where the inorganic phase accounts for 10wt% of the total mass of the organic phase, inorganic phase, and electrolyte salt. After further stirring, the mixed solution is cast onto a polytetrafluoroethylene plate and vacuum-dried at 60°C for 24 hours. After the N,N-dimethylformamide is fully evaporated, a composite solid electrolyte film with a thickness of approximately 40μm is obtained.

[0131] 3. Preparation of solid-state batteries

[0132] In an argon-protected glove box, the composite solid electrolyte film was placed between a sodium vanadium phosphate (Na3V2(PO4)3) cathode and a sodium metal anode (Na). A trace amount (2 μL / cm2 ) carbonate-based electrolyte (1M NaPF6 / EC+DEC (mass ratio 1:1)) is used to infiltrate the interior of the positive electrode and form the necessary ion-conducting network. After being encapsulated in a 2032-type button battery shell, a Na||Na3V2(PO4)3 solid-state battery is obtained.

[0133] Example 9

[0134] This embodiment provides a method for preparing another modified oxide solid electrolyte material and the application of the material in composite solid electrolytes and solid-state batteries.

[0135] 1. Modified oxide solid electrolyte material Na3Zr2Si2PO 12 @Sr2Nb2O7+Bi4Ti3O 12 Preparation

[0136] Preparation of sintering precursor: The first component of the ferroelectric ceramic Sr2Nb2O7 precursor particles is SrCO3, and the second component is Nb2O5, with a stoichiometric ratio of 2:1. 0.295g SrCO3 particles (ground and sieved <500nm), 0.266g Nb2O5 particles (ground and sieved <500nm), 0.006g sintering aid Bi4Ti3O 12 Particles (ground and sieved <500 nm) and 3.179 g Na3Zr2Si2PO 12 The particles (ground and sieved to 2-15 μm) were added to a beaker containing 20 mL of anhydrous ethanol and magnetically stirred at 30 °C for 6 h. They were then dried at 70 °C for 24 h to completely evaporate the anhydrous ethanol. The remaining material was ground in an agate mortar to obtain a sintering precursor.

[0137] Joule heat high temperature rapid sintering: The sintering precursor is placed between two layers of carbon paper in a Joule heat rapid sintering device, the sintering temperature is controlled at 1250°C, the heating time is 6 seconds, the sintering time is 45 seconds, and the sintering atmosphere is air. After natural cooling, it is ground to obtain the modified oxide solid electrolyte material Na3Zr2Si2PO 12 @Sr2Nb2O7+Bi4Ti3O 12 .

[0138] 2. Preparation of composite solid electrolyte

[0139] The composite solid electrolyte was prepared by solution casting method: the electrolyte salt NaTFSI and the organic phase PVDF-HFP were dissolved in an appropriate amount of N,N-dimethylformamide in a mass ratio of 1:1, and after stirring and fully dissolving, the inorganic phase (Na3Zr2Si2PO 12 @Sr2Nb2O7+Bi4Ti3O 12), wherein the inorganic phase accounts for 20 wt% of the total mass of the organic phase, inorganic phase, and electrolyte salt. After further stirring, the mixed solution is cast onto a polytetrafluoroethylene plate and vacuum-dried at 60°C for 24 hours. After the N,N-dimethylformamide is fully evaporated, a composite solid electrolyte film with a thickness of approximately 60 μm is obtained.

[0140] 3. Preparation of solid-state batteries

[0141] In an argon-protected glove box, the composite solid electrolyte film was placed between a sodium vanadium phosphate (Na3V2(PO4)3) cathode and a sodium metal anode (Na). A trace amount (3 μL / cm 2 ) carbonate-based electrolyte (1M NaTFSI / EC+DEC (mass ratio 1:1)) is used to infiltrate the interior of the positive electrode and form the necessary ion-conducting network. After being encapsulated in a 2032-type button battery shell, a Na||Na3V2(PO4)3 solid-state battery is obtained.

[0142] Comparative Example 1

[0143] This comparative example provides a modified oxide solid electrolyte material, which adopts the same implementation as Example 1, with the only difference being that the sintering process is a traditional high-temperature sintering method. Other process steps and parameter conditions are the same as Example 1.

[0144] The specific steps are as follows:

[0145] 1. Modified oxide solid electrolyte material Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Preparation of @BaTiO3+KNbO3

[0146] Preparation of sintering precursor: same as in Example 1.

[0147] Traditional high-temperature sintering method: sintering in a muffle furnace, placing the sintered precursor in an alumina crucible, controlling the sintering temperature to 1200°C, the heating time to 200 minutes, the sintering time to 8 hours, and the sintering atmosphere to air. After natural cooling, grinding is performed to obtain the modified oxide solid electrolyte material Li 6.4 La3Zr 1.4 Ta 0.6 O 12 @BaTiO3+KNbO3.

[0148] 2. Preparation of composite solid electrolyte

[0149] The composite solid electrolyte was prepared by solution casting method: refer to Example 1.

[0150] 3. Preparation of solid-state batteries

[0151] Refer to Example 1.

[0152] Comparative Example 2

[0153] This comparative example provides a modified oxide solid electrolyte material, which is implemented in the same manner as in Example 1, with the only difference being that no sintering aid is added during the step of preparing the sintering precursor. Other process steps and parameter conditions are the same as in Example 1.

[0154] 1. Modified oxide solid electrolyte material Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Preparation of @BaTiO3

[0155] Preparation of sintering precursor: The first component of the ferroelectric ceramic BaTiO3 precursor particles is BaCO3, and the second component is TiO2, with a stoichiometric ratio of 1:1. 0.197g BaCO3 particles (grinded and sieved <500nm), 0.080g TiO2 particles (raw material 40nm) and 1.262g Li 6.4 La3Zr 1.4 Ta 0.6 O 12 The particles (ground and sieved to 2-15 μm) were added to a beaker containing 20 mL of anhydrous ethanol and magnetically stirred at 30 °C for 6 h. They were then dried at 60 °C for 24 h to completely evaporate the anhydrous ethanol. The remaining material was ground in an agate mortar to obtain a sintering precursor.

[0156] Joule heat high temperature rapid sintering: refer to Example 1.

[0157] 2. Preparation of composite solid electrolyte

[0158] The composite solid electrolyte was prepared by solution casting method: refer to Example 1.

[0159] 3. Preparation of solid-state batteries

[0160] Refer to Example 1.

[0161] Comparative Example 3

[0162] In this comparative example, Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Materials for preparing composite solid electrolytes and solid-state batteries, with other process steps and parameter conditions being the same as those in Example 1.

[0163] 1. Preparation of composite solid electrolyte

[0164] The composite solid electrolyte was prepared by solution casting method: refer to Example 1.

[0165] 2. Preparation of solid-state batteries

[0166] Refer to Example 1.

[0167] Comparative Example 4

[0168] This comparative example provides a modified oxide solid electrolyte material, which adopts the same implementation as Example 2, except that the sintering process is a traditional high-temperature sintering method. Other process steps and parameter conditions are the same as Example 2.

[0169] 1. Modified oxide solid electrolyte material Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Preparation of @SrTiO3+KNbO3

[0170] Preparation of sintering precursor: same as Example 2.

[0171] Traditional high-temperature sintering method: sintering in a muffle furnace, placing the sintered precursor in an alumina crucible, controlling the sintering temperature to 1400°C, heating time to 280min, sintering time to 8h, and sintering atmosphere to nitrogen. After natural cooling, grinding is performed to obtain the modified oxide solid electrolyte material Li 6.4 La3Zr 1.4 Ta 0.6 O 12 @SrTiO3+KNbO3.

[0172] 2. Preparation of composite solid electrolyte

[0173] The composite solid electrolyte was prepared by solution casting method: refer to Example 2.

[0174] 3. Preparation of solid-state batteries

[0175] Refer to Example 2.

[0176] Performance Testing

[0177] Figure 1 For the original Li 6.4 La3Zr 1.4 Ta 0.6 O 12 SEM images of particles. Figure 2 Li prepared according to Example 1 6.4 La3Zr 1.4 Ta 0.6 O 12 @SEM image of BaTiO3+KNbO3 material, Figure 3Li prepared according to Example 1 6.4 La3Zr 1.4 Ta 0.6 O 12 @BaTiO3+KNbO3 material XRD spectrum. It can be seen that the use of Joule heat high temperature in situ solid phase reaction method effectively achieved the pure phase BaTiO3 in Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Surface coating, and Li 6.4 La3Zr 1.4 Ta 0.6 O 12 The core also maintained high purity, proving that the method is efficient and feasible. Figure 4 Li prepared according to Comparative Example 1 6.4 La3Zr 1.4 Ta 0.6 O 12 @From the SEM image of BaTiO3+KNbO3 material, it can be seen that the use of Joule heat high-temperature sintering technology achieves better coating uniformity compared to traditional high-temperature sintering methods. Figure 5 Li prepared according to Comparative Example 2 6.4 La3Zr 1.4 Ta 0.6 O 12 @The SEM image of BaTiO3 material shows that combining sintering aids with Joule heat high-temperature sintering technology can achieve better coating uniformity.

[0178] The performance of the composite solid electrolytes and solid secondary batteries in Examples 1 to 9 and Comparative Examples 1 to 4 were compared. The ionic conductivity and ion transference number of the composite solid electrolyte were tested using a Chenhua CHI650F electrochemical workstation. The ionic conductivity was calculated using the formula σ = l / (R b ×s) calculation, where R b is the bulk impedance obtained by fitting the electrochemical impedance spectrum after testing the steel sheet symmetrical battery, l is the thickness of the solid electrolyte, and s is the area of the solid electrolyte. Li + ) is calculated by the following formula:

[0179]

[0180] The polarization voltage ΔV applied in the test is 10mV, I0 is the initial current, I S is the steady-state current, R0 and R SThe charge and discharge cycle performance of the battery was tested on a Xinwei battery test system. The charge and discharge voltage range of the Li||NCM811 battery was 2.8-4.3V, the charge and discharge voltage range of the Li||LiFePO4 battery was 2.5-3.8V, the charge and discharge voltage range of the Li||LiCoO2 battery was 3.0-4.5V, and the charge and discharge voltage range of the Na||Na3V2(PO4)3 battery was 2.0-4.0V. The charge and discharge current was 0.5C.

[0181] The test results are shown in Table 1 and Figure 6-Figure 8 .

[0182] Table 1 Performance tests of solid electrolytes and batteries in Examples and Comparative Examples

[0183]

[0184] It can be seen that the use of Li 6.4 La3Zr 1.4 Ta 0.6 O 12 @BaTiO3 as the inorganic phase and adding sintering aid KNbO3 in Example 1 and Comparative Example 1, and using Li 6.4 La3Zr 1.4 Ta 0.6 O 12 @Comparative Example 2, in which BaTiO3 is used as the inorganic phase but no sintering aid KNbO3 is added, has better ionic conductivity, lithium ion transference number and cycle capacity retention than directly using Li 6.4 La3Zr 1.4 Ta 0.6 O 12 Comparative Example 3, which uses an inorganic phase, demonstrates that the spontaneous polarization effect generated by the ferroelectric ceramic BaTiO3 coating effectively suppresses surface side reactions, regulates the internal electric field of the composite solid electrolyte, and improves the efficiency of lithium ion transfer and interfacial exchange, thereby significantly improving battery performance. Furthermore, compared to Comparative Example 1, which uses traditional high-temperature sintering for coating, Examples 1 and 2, which use Joule heat high-temperature rapid sintering for coating, further improve electrochemical properties such as ionic conductivity, lithium ion transfer number, and cycle capacity retention, demonstrating that the Joule heat high-temperature rapid sintering method achieves better coating uniformity. Furthermore, compared with Comparative Example 2 which does not use a sintering aid, Example 1 which uses a sintering aid can obtain higher ionic conductivity. This is because the Joule heat high-temperature rapid sintering method has a short sintering time (<100s) and a limited material diffusion rate. An appropriate amount of sintering aid promotes the transfer of coating layer materials in liquid form during the sintering process, promotes a more complete reaction, and further improves the coating uniformity. At the same time, the sintering aid itself is also a ferroelectric ceramic material, which also contributes to the spontaneous polarization effect and surface electric field regulation.

[0185] It can also be seen from the results of Example 2 and Comparative Example 4 that compared with the conventional high temperature sintering method, 6.4 La3Zr 1.4 Ta 0.6 O 12 Comparative Example 4 in which the surface is coated with SrTiO3 and Example 2 in which SrTiO3 is coated by Joule heat and high-temperature rapid sintering are used further improve the electrochemical properties such as ionic conductivity, lithium ion migration number and cycle capacity retention rate, which also proves that the Joule heat and high-temperature rapid sintering method obtains better coating uniformity to improve performance.

[0186] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for preparing a modified oxide solid electrolyte material, characterized in that: The following steps are involved: uniformly blending ferroelectric ceramic precursor particles, oxide solid electrolyte and sintering aid to obtain a sintering precursor; The sintering precursor is subjected to high-temperature sintering by Joule heat rapid sintering to obtain a modified oxide solid electrolyte material; The ferroelectric ceramic precursor particles include a first component and a second component, wherein the first component is a carbonate or oxide of a metal M, and the metal M is Ba, Sr, La or Ca; and the second component is an oxide of a metal N, and the metal N is Ti or Nb. The sintering aid is a ferroelectric ceramic material with a melting point of 850-1250°C; The mass ratio of the ferroelectric ceramic precursor particles to the oxide solid electrolyte is (0.2~25):100, the mass of the oxide solid electrolyte accounts for 80.0%~99.8% of the mass of the sintering precursor, and the mass of the sintering aid accounts for 0.2%~6% of the mass of the ferroelectric ceramic precursor particles.

2. The preparation method according to claim 1, wherein The first component is one of BaCO3, SrCO3, La2O3, and CaCO3; the second component is TiO2 or Nb2O5.

3. The preparation method according to claim 1, wherein The oxide solid electrolyte is at least one of lithium lanthanum zirconium oxide, tantalum-doped lithium lanthanum zirconium oxide, and sodium zirconium silicon phosphorus oxide.

4. The preparation method according to claim 1, wherein The sintering aid is KNbO3, BiFeO3, Bi4Ti3O 12 At least one of .

5. The preparation method according to claim 1, wherein The particle size of the ferroelectric ceramic precursor particles is less than 500 nm; and / or the particle size of the sintering aid is less than 500 nm; and / or the particle size of the oxide solid electrolyte is 2-15 μm.

6. The preparation method according to claim 1, wherein The sintering temperature of the Joule heat rapid sintering is 1000-1600° C., the heating time is 3-15 seconds, and the sintering time is 3-100 seconds; the sintering atmosphere is air, nitrogen or argon.

7. Use of the modified oxide solid electrolyte material obtained by the preparation method according to any one of claims 1 to 6 in the preparation of a composite solid electrolyte or a solid-state battery.

8. A composite solid electrolyte comprising an electrolyte salt, an organic phase and an inorganic phase, characterized in that: The inorganic phase is a modified oxide solid electrolyte material prepared by the preparation method according to any one of claims 1 to 6.

9. The composite solid electrolyte according to claim 8, characterized in that The mass ratio of the inorganic phase to the total mass of the composite solid electrolyte is 0.5 wt% to 50 wt%.

10. The composite solid electrolyte according to claim 9, characterized in that The mass ratio of the inorganic phase to the total mass of the composite solid electrolyte is 5wt% to 20wt%.

11. The composite solid electrolyte according to claim 8, characterized in that The organic phase is at least one of polyethylene oxide, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyacrylonitrile, polymethyl methacrylate, and polypropylene carbonate.

12. The composite solid electrolyte according to claim 8, wherein The electrolyte salt is a lithium salt or a sodium salt.

13. A solid-state battery, characterized in that: The solid-state battery contains the composite solid-state electrolyte according to any one of claims 8 to 12.

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