Preparation method of LATP solid electrolyte with high ionic conductivity

Abstract

The invention discloses a preparation method of a high ionic conductivity LATP solid electrolyte, which comprises the following steps: dispersing an aluminum source, a titanium-containing additive and NH4H2PO4 in a solvent according to a certain ratio, and carrying out ball milling mixing and drying to obtain a first precursor, the titanium-containing additive comprising TiF4; dispersing Li2CO3 and the first precursor in a solvent according to a certain proportion, and carrying out ball-milling mixing and drying to obtain a second precursor; performing high-temperature crystallization sintering on the second precursor, and cooling to obtain first powder; mixing Li3PO4 and the first powder, then carrying out ball-milling mixing and drying, and drying to obtain second powder; and performing high-temperature crystallization sintering on the second powder to obtain the LATP solid electrolyte, so that the generation of a secondary phase can be reduced, the crystal purity can be improved, the bulk phase ionic conductivity can be improved, the grain boundary influence can be reduced, and the grain boundary ionic conductivity can be improved while the high crystallinity of the LATP can be ensured under the condition of short-time sintering.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electrolyte preparation methods, and particularly relates to a preparation method of a high-ionic-conductivity LATP solid-state electrolyte. BACKGROUND

[0002] LATP (Li 1.3 Al 0.3 Ti 1.7 (PO4)3) is a solid-state electrolyte material based on the sodium superionic conductor (NASICON) structure, and its crystal framework is composed of PO4 tetrahedron and (Ti, Al)O6 octahedron connected by oxygen bridges to form a three-dimensional ion transport network. Thanks to its unique open crystal structure, this material exhibits excellent lithium ion conductivity, with a room-temperature ionic conductivity of 10 -4 ~10 -3 S / cm order of magnitude, which provides a key material basis for improving the power density and electrochemical kinetic performance of lithium ion batteries.

[0003] In addition to the high ionic conductivity, LATP also has multiple technical advantages: the material exhibits excellent chemical inertness in air environment (ionic conductivity decay rate < 5% after 24 hours of exposure), a wide electrochemical stability window (0-5 V vs. Li⁺ / Li) that can adapt to high-voltage positive electrode systems, and thermal stability (decomposition temperature > 800℃). In terms of application scenarios, the material can not only be coated on the surface of the separator through atomic layer deposition technology (ALD) or used as an interfacial coating layer of positive active materials (such as NCM, LFP), but also can be innovatively used in the form of nano-powder (particle size < 200 nm) as an electrode additive, which can significantly improve the rate performance and low-temperature working ability of the battery by optimizing the lithium ion transport path at the electrode / electrolyte interface.

[0004] In the actual preparation process of LATP, the lithium ion transmission efficiency between LATP particles is low due to the influence of the interface, and high-temperature sintering is usually used to improve the density to reduce the influence of the interface. However, traditional high-temperature sintering (above 950℃) for preparing LATP can cause rapid lithium evaporation and the generation of a secondary phase with low ionic conductivity. Most current technologies use lithium salt supplementation and flux addition to prepare high-density, low-interface-resistance LATP at a lower temperature. This method usually requires a longer holding time due to the reduced crystallization temperature, which is not conducive to improving production efficiency, and low-temperature crystallization can easily lead to low bulk crystallinity, which is not conducive to the ionic conductivity of the bulk phase. SUMMARY

[0005] In view of the above-mentioned deficiencies in the field of electrolyte preparation methods, the present application provides a preparation method of a high ionic conductivity LATP solid electrolyte, which can ensure high crystallinity of the LATP while reducing the generation of secondary phases, improving the purity of the crystal, improving the bulk phase ionic conductivity, reducing the influence of the grain boundary, and improving the grain boundary ionic conductivity under short-time sintering conditions.

[0006] To achieve the above-mentioned purposes, the embodiments of the present application adopt the following technical solutions: A preparation method of a high ionic conductivity LATP solid electrolyte, comprising the following steps: An aluminum source, a titanium-containing additive, and NH4H2PO4 are dispersed in a solvent in a certain proportion, and are mixed by ball milling and dried to obtain a first precursor, wherein the titanium-containing additive comprises TiF4. Li2CO3 and the first precursor are dispersed in a solvent in a certain proportion, and are mixed by ball milling and dried to obtain a second precursor. The second precursor is subjected to high-temperature crystallization sintering and cooling to obtain a first powder. Li3PO4 and the first powder are mixed, ball-mixed, and dried to obtain a second powder. The second powder is subjected to high-temperature crystallization sintering to obtain a LATP solid electrolyte.

[0007] According to an aspect of the present application, the titanium-containing additive is mainly TiO2, and a part of TiO2 is replaced by TiF4, and the replacement ratio is at least 0.5wt% and at most 2wt%.

[0008] According to an aspect of the present application, in the step of dispersing the aluminum source, the titanium-containing additive, and NH4H2PO4 in the solvent in a certain proportion, the stoichiometric ratio of aluminum, titanium, and phosphoric acid is 0.3:1.7:3.

[0009] According to an aspect of the present application, in the step of dispersing the aluminum source, the titanium-containing additive, and NH4H2PO4 in the solvent in a certain proportion, and mixing by ball milling and drying to obtain the first precursor, the ball milling mixing mode is ethanol wet ball milling mixing, the ball-to-material ratio is 1:10, and the first slurry is formed by keeping the rotation speed at 300rpm for 2h.

[0010] According to an aspect of the present application, the first slurry is blown and dried in a 60℃ environment, and the first precursor is obtained by keeping the temperature at 300℃ for five hours.

[0011] According to one aspect of the present application, in the step of dispersing Li2CO3 and the first precursor in a solvent in a certain proportion and mixing by ball milling and drying to obtain the second precursor, the Li2CO3 and the first precursor are dispersed in ethanol in a mass ratio of 1:10, the ball milling is ethanol wet ball milling, the ratio of material to ball is 1:10, and the second slurry is formed by keeping the rotation speed at 300 rpm for 2 hours.

[0012] According to one aspect of the present application, in the step of high-temperature crystallization sintering the second precursor and cooling to obtain the first powder, the second precursor is heated to a first specified temperature at a first heating rate, and then cooled to room temperature after keeping the temperature for 30 minutes, the first heating rate is at least 2℃ / min and at most 3℃ / min, and the first specified temperature is at least 950℃ and at most 1000℃.

[0013] According to one aspect of the present application, in the step of mixing Li3PO4 and the first powder and then mixing by ball milling and drying to obtain the second powder, the mass of Li3PO4 is at least 1wt% and at most 3wt%.

[0014] According to one aspect of the present application, in the step of ball milling, the ball milling includes ethanol wet ball milling, the ratio of material to ball is 1:10, and the third slurry is formed by keeping the rotation speed at a specified speed for a specified time, the specified speed is at least 300 rpm and at most 600 rpm, and the specified time is at least 3 hours and at most 6 hours.

[0015] According to one aspect of the present application, in the step of high-temperature crystallization sintering the second powder to obtain the LATP solid-state electrolyte, the second powder is heated to a second specified temperature at a second heating rate, and then crystallized after keeping the temperature, the second heating rate is at least 2℃ / min and at most 3℃ / min, and the second specified temperature is at least 750℃ and at most 800℃.

[0016] Advantages of the present application: by dispersing the aluminum source, the titanium-containing additive and NH4H2PO4 in a solvent in a certain proportion, and mixing by ball milling and drying to obtain the first precursor, the titanium-containing additive includes TiF4; dispersing Li2CO3 and the first precursor in a solvent in a certain proportion, and mixing by ball milling and drying to obtain the second precursor; high-temperature crystallization sintering the second precursor and cooling to obtain the first powder; mixing Li3PO4 and the first powder, and then mixing by ball milling and drying to obtain the second powder; high-temperature crystallization sintering the second powder to obtain the LATP solid-state electrolyte, the high crystallinity of the LATP can be ensured under the condition of short-time sintering, the generation of secondary phases is reduced, the crystal purity is improved, the bulk ion conductivity is improved, the influence of the grain boundary is reduced, and the grain boundary ion conductivity is improved. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description only represent some of the embodiments of the present application, and other drawings can be obtained by those of ordinary skill in the art without any creative effort based on these drawings.

[0018] Figure 1 A flowchart of a preparation method of the high-ionic-conductivity LATP solid-state electrolyte according to the present application; Figure 2 A result graph of Comparative Example 1 of the preparation method of the high-ionic-conductivity LATP solid-state electrolyte according to the present application; Figure 3 A result graph of Example 1 of the preparation method of the high-ionic-conductivity LATP solid-state electrolyte according to the present application; Figure 4 A result graph of Example 2 of the preparation method of the high-ionic-conductivity LATP solid-state electrolyte according to the present application; Figure 5 A comparison graph of Comparative Example 1, Example 1 and Example 2 of the preparation method of the high-ionic-conductivity LATP solid-state electrolyte according to the present application. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings of the embodiments of the present application. Obviously, the described embodiments only represent some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without any creative effort belong to the scope of protection of the present application.

[0020] Comparative Example 1, Example 1 and Example 2 are set up for comparison experiments.

[0021] Comparative Example 1 S1: Disperse aluminum source, titanium-containing additive and NH4H2PO4 in a solvent according to a certain proportion, and mix and dry by ball milling to obtain a first precursor.

[0022] The aluminum source, titanium-containing additive, and NH4H2PO4 are simply dispersed in ethanol according to a certain stoichiometric ratio, wherein the aluminum source is mainly Al2O3 and TiO2, and the stoichiometric ratio of aluminum, titanium, and phosphoric acid is 0.3:1.7:3. Then, the mixture is mixed by ethanol wet ball milling, wherein the material-to-ball ratio is 1:10, the rotation speed is 300 rpm, the holding time is 2 h, and a first slurry is formed. The first slurry is air-dried at 60°C, then heat-treated at 300°C for 5 h, and a first precursor is prepared, and a powder is formed.

[0023] S2: The lithium source and the first precursor are dispersed in a solvent according to a certain ratio, and mixed by ball milling and dried to obtain a second precursor.

[0024] The lithium source and the powder of the first precursor are simply dispersed in ethanol according to a mass ratio of 1:10, and then mixed by ball milling. The lithium source can be Li2CO3, etc. The material-to-ball ratio is 1:10, the rotation speed is 300 rpm, the holding time is 2 h, and a second slurry is formed. The second slurry is air-dried at 60°C, and a second precursor is prepared, and a powder is formed.

[0025] S3: The second precursor is subjected to high-temperature crystallization sintering, and the temperature is lowered to obtain a first powder.

[0026] The powder of the second precursor is subjected to high-temperature crystallization sintering, and the temperature is raised to 950°C at a rate of 3°C / min, and heat-treated for 30 min, and then lowered to room temperature to obtain a first powder. The first powder is the powder obtained after the second precursor is subjected to high-temperature crystallization sintering and the temperature is lowered.

[0027] S4: The first powder is mixed, ball-milled, and dried, and a second powder is obtained after drying.

[0028] The first powder is mixed and ball-milled, the material-to-ball ratio is 1:10, the rotation speed is 300-600 rpm, the holding time is 6 h, and a third slurry is formed. The third slurry is dried at 60°C, and a second powder is obtained after drying.

[0029] S5: The second powder is heat-treated at 800°C for 6 h to obtain a LATP solid-state electrolyte.

[0030] As shown in Figure 2 Example 1, the LATP is synthesized by a conventional raw material according to a solid-phase method. Due to the slow diffusion of Ti elements, impurities such as TiO2, Li2TiO3, and Li2O2 are easily formed at high temperatures, which affects the ion conductivity performance, and the actual ion conductivity is 0.160 mS / cm. 0.5 Ti 0.5 O2, etc., which affects the ion conductivity performance, and the actual ion conductivity is 0.160 mS / cm.

[0031] Example 1

[0032] A preparation method of a high-ionic-conductivity LATP solid-state electrolyte, comprising the following steps: S1: dispersing an aluminum source, a titanium-containing additive, and NH4H2PO4 in a solvent according to a certain proportion, and mixing by ball milling and drying to obtain a first precursor.

[0033] The aluminum source, the titanium-containing additive, and NH4H2PO4 are simply dispersed in ethanol according to a certain stoichiometric ratio, wherein the aluminum source and the titanium-containing additive are mainly Al2O3 and TiO2, and the stoichiometric ratio of aluminum, titanium, and phosphoric acid is 0.3:1.7:3. In addition, 1wt% TiF4 is added as an additive in this embodiment. Then, the mixture is mixed by an ethanol wet ball milling method, wherein the material-to-ball ratio is 1:10, the rotation speed is 300 rpm, the holding time is 2h, and a first slurry is formed. The first slurry is dried by blowing at 60°C, and then heat-treated at 300°C for 5h to obtain the first precursor and form a powder.

[0034] S2: dispersing a lithium source and the first precursor in a solvent according to a certain proportion, and mixing by ball milling and drying to obtain a second precursor.

[0035] The lithium source and the powder of the first precursor are simply dispersed in ethanol according to a mass ratio of 1:10, and then mixed by ball milling. The lithium source can be Li2CO3, etc. The material-to-ball ratio is 1:10, the rotation speed is 300 rpm, the holding time is 2h, and a second slurry is formed. The second slurry is dried by blowing at 60°C, and then heat-treated at 300°C for 5h to obtain the second precursor and form a powder.

[0036] S3: high-temperature crystallization sintering the second precursor, and cooling to obtain a first powder.

[0037] The powder of the second precursor is subjected to high-temperature crystallization sintering, and heated to 950°C at a heating rate of 3°C / min and heat-treated for 30min, and then cooled to room temperature to obtain the first powder. The first powder is the powder obtained after the second precursor is subjected to high-temperature crystallization sintering and cooling.

[0038] S4: mixing the first powder, and then ball milling and drying to obtain a second powder.

[0039] The first powder is mixed and ball milled, the material-to-ball ratio is 1:10, the rotation speed is 300-600 rpm, the holding time is 6h, and a third slurry is formed. The third slurry is dried at 60°C, and then dried to obtain the second powder.

[0040] S5: heat-treating the second powder at 800°C for 6h to obtain a LATP solid-state electrolyte.

[0041] As Figure 3As shown, in Example One, due to the introduction of a small amount of TiF4, the diffusion of Ti element at high temperature is promoted, forming LATP with purer crystal phase and higher crystallinity, and the actual ionic conductivity of Example One is 0.467 mS / cm.

[0042] Example Two

[0043] A preparation method of a high ionic conductivity LATP solid-state electrolyte, comprising the following steps: S1: dispersing an aluminum source, a titanium-containing additive, and NH4H2PO4 in a solvent according to a certain proportion, and mixing and drying by ball milling to obtain a first precursor.

[0044] The aluminum source, the titanium-containing additive, and NH4H2PO4 are simply dispersed in ethanol according to a certain stoichiometric ratio, wherein the aluminum source and the titanium-containing additive are mainly Al2O3 and TiO2, and the stoichiometric ratio of aluminum, titanium, and phosphoric acid is 0.3:1.7:3. In addition, 1wt% TiF4 is added as an additive. Then, the mixture is mixed by ethanol wet ball milling, wherein the material ball ratio is 1:10, the rotation speed is 300 rpm, the holding time is 2h, and a first slurry is formed. The first slurry is dried at 60°C under air blowing, and then heat treated at 300°C for 5 hours to obtain the first precursor and form a powder.

[0045] S2: dispersing a lithium source and the first precursor in a solvent according to a certain proportion, and mixing and drying by ball milling to obtain a second precursor.

[0046] The lithium source and the powder of the first precursor are simply dispersed in ethanol according to a mass ratio of 1:10, and then mixed by ball milling. The lithium source can be Li2CO3, etc. The material ball ratio is 1:10, the rotation speed is 300 rpm, the holding time is 2h, and a second slurry is formed. The second slurry is dried at 60°C under air blowing, and a second precursor is obtained and a powder is formed.

[0047] S3: high-temperature crystallization sintering the second precursor, and cooling to obtain a first powder.

[0048] The powder of the second precursor is subjected to high-temperature crystallization sintering, and heated to 950°C-1000°C at a heating rate of 3°C / min and heat treated for 30min, and then cooled to room temperature to obtain a first powder. The first powder is a powder obtained by high-temperature crystallization sintering and cooling of the second precursor.

[0049] S4: mixing Li3PO4 and the first powder, and mixing and drying by ball milling to obtain a second powder after drying.

[0050] The third slurry is formed by mixing 3wt% Li3PO4 and the first powder and ball-milling, the ratio of material to ball is 1:10, the rotating speed is 300-600rpm, the holding time is 6h and the third slurry is formed. The third slurry is dried at 60℃, and the second powder is obtained after drying.

[0051] S5: the second powder is kept at 800℃ for 6h to obtain the LATP solid electrolyte.

[0052] As shown in Figure 4 , Figure 5 Example two introduces the sample of Li3PO4 after high temperature as Li3PO4 coated LATP, but there is no other impurities. The introduction of Li3PO4 is mainly to reduce the impedance of ions between the interface and improve the ionic conductivity. The actual ionic conductivity of example two is 0.738 mS / cm.

[0053] The advantages of the embodiment of the application are as follows: the aluminum source, the titanium-containing additive and NH4H2PO4 are dispersed in a solvent according to a certain proportion, and are mixed by ball-milling and dried to obtain a first precursor, the titanium-containing additive includes TiF4; Li2CO3 and the first precursor are dispersed in a solvent according to a certain proportion, and are mixed by ball-milling and dried to obtain a second precursor; the second precursor is subjected to high-temperature crystallization sintering and cooling to obtain a first powder; Li3PO4 and the first powder are mixed and then ball-milled and dried to obtain a second powder; the second powder is subjected to high-temperature crystallization sintering to obtain a LATP solid electrolyte, which can ensure high crystallinity of the LATP, reduce the generation of secondary phases, improve the purity of the crystal, improve the bulk phase ionic conductivity, reduce the influence of the grain boundary and improve the ionic conductivity of the grain boundary in the case of short-time sintering.

[0054] Example three

[0055] A high-ionic-conductivity LATP solid electrolyte is realized based on the preparation method of the high-ionic-conductivity LATP solid electrolyte in example three.

[0056] The aluminum source, the titanium-containing additive and NH4H2PO4 are simply dispersed in ethanol according to a certain stoichiometric ratio, the aluminum source and the titanium-containing additive are mainly Al2O3 and TiO2, and the stoichiometric ratio of aluminum, titanium and phosphoric acid is 0.3:1.7:3. TiF4 is used to replace part of TiO2 in this embodiment, and the replacement ratio is 0.5wt%-2wt%. Then the first slurry is formed by ethanol wet ball-milling, the ratio of material to ball is 1:10, the rotating speed is 300rpm, and the holding time is 2h. The first slurry is dried by blowing at 60℃, and then the first precursor is prepared by keeping at 300℃ for 5h, and a powder is formed.

[0057] The Li2CO3 and the first precursor powder are simply dispersed in ethanol with a mass ratio of 1:10, and then mixed by ball milling, with a ball-to-material ratio of 1:10, a rotation speed of 300 rpm, a holding time of 2 h, and a second slurry is formed. The second slurry is dried by blowing at 60°C, and a second precursor is prepared, and a powder is formed.

[0058] The powder of the second precursor is subjected to high-temperature crystallization sintering, and is heated to 950-1000°C at a heating rate of 2-3°C / min, and is kept for 30 min, and after being reduced to room temperature, a first powder is obtained. The first powder is a powder obtained after the second precursor is subjected to high-temperature crystallization sintering and cooling.

[0059] In this process, since part of TiO2 is replaced by TiF4 in the raw material mixing stage, active Ti-F at high temperature helps to generate Al(Ti)-O-P, so that LATP rapidly forms stable and high-crystallinity LATP crystals within 1 h at a temperature of 950°C. Since the high-temperature stage is short in time, the secondary phase with low ionic conductivity is generated less.

[0060] The Li3PO4 and the first powder are mixed, with the mass fraction of Li3PO4 being 1wt%-3wt%, and the mixing method being ethanol wet ball milling, with a ball-to-material ratio of 1:10, a rotation speed of 300-600 rpm, a holding time of 3-6 h, and a third slurry is formed. The third slurry is dried at 60-70°C, and a second powder is obtained after drying.

[0061] The second powder is subjected to high-temperature crystallization sintering, and is heated to 750-800°C at a heating rate of 2-3°C / min, and then kept for 2-6 h to induce its secondary crystallization, and a final high-crystallinity and high-ionic-conductivity LATP solid-state electrolyte is formed.

[0062] In this process, Li3PO4 will start to enter a molten state after 750°C during sintering, and will coat the surface of the LATP crystal grains and fill the intergranular gaps. During the holding process, part of the secondary phase generated during the high-temperature crystallization process will react with Li3PO4, causing the Al and Ti elements in part of the secondary phase to diffuse into the interstitial molten Li3PO4 and recrystallize, improving the overall density and ionic conductivity, and repairing the grain boundary defects and reducing the grain boundary resistance.

[0063] The embodiment of the present application has the following advantages: by dispersing the aluminum source, the titanium-containing additive and NH4H2PO4 in a solvent according to a certain proportion, and by ball-milling mixing and drying, a first precursor is obtained, wherein the titanium-containing additive comprises TiF4; by dispersing Li2CO3 and the first precursor in a solvent according to a certain proportion, and by ball-milling mixing and drying, a second precursor is obtained; by high-temperature crystallization sintering the second precursor, and by cooling, a first powder is obtained; by mixing Li3PO4 and the first powder, and by ball-milling mixing and drying, a second powder is obtained; by high-temperature crystallization sintering the second powder, a LATP solid-state electrolyte is obtained, which can ensure high crystallinity of the LATP, reduce the generation of secondary phases, improve the crystal purity, improve the bulk ion conductivity, reduce the influence of the grain boundary, and improve the grain boundary ion conductivity under the condition of short-time sintering.

[0064] The above merely provides a specific implementation of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for producing a high ionic conductivity LATP solid state electrolyte, characterized by, The method comprises the following steps: dispersing an aluminum source, a titanium-containing additive and NH4H2PO4 in a solvent according to a certain proportion, and mixing and drying by ball milling to obtain a first precursor, wherein the titanium-containing additive comprises TiF4; dispersing Li2CO3 and the first precursor in a solvent according to a certain proportion, and mixing and drying by ball milling to obtain a second precursor; high-temperature crystallization sintering the second precursor, and cooling to obtain a first powder; mixing Li3PO4 and the first powder, and then mixing and drying by ball milling to obtain a second powder; high-temperature crystallization sintering the second powder to obtain a LATP solid-state electrolyte.

2. The method of producing a high-ionic-conductivity LATP solid-state electrolyte according to claim 1, characterized by, The titanium-containing additive is mainly TiO2, and a part of TiO2 is replaced by TiF4, and the replacement proportion is at least 0.5wt% and at most 2wt%.

3. The method of producing a high-ionic-conductivity LATP solid-state electrolyte according to claim 1, characterized by, In the dispersing of the aluminum source, the titanium-containing additive and NH4H2PO4 in the solvent according to a certain proportion, the stoichiometric ratio of aluminum, titanium and phosphoric acid is 0.3:1.7:

3.

4. The method of producing a high-ionic-conductivity LATP solid-state electrolyte according to claim 1, characterized by, In the dispersing of the aluminum source, the titanium-containing additive and NH4H2PO4 in the solvent according to a certain proportion, and mixing and drying by ball milling to obtain the first precursor, the ball milling is ethanol wet ball milling, the ratio of material to ball is 1:10, and the first slurry is formed by keeping the rotation speed at 300rpm for 2h.

5. The method of producing a high-ionic-conductivity LATP solid-state electrolyte according to claim 4, characterized by, The first slurry is dried by blowing air in an environment of 60℃, and the first precursor is obtained by keeping the temperature at 300℃ for 5h.

6. The method for preparing the LATP solid electrolyte with high ionic conductivity according to claim 1, characterized in that, In the dispersing of Li2CO3 and the first precursor in a solvent according to a certain proportion, and mixing and drying by ball milling to obtain the second precursor, Li2CO3 and the first precursor are dispersed in ethanol according to a mass ratio of 1:10, the ball milling is ethanol wet ball milling, the ratio of material to ball is 1:10, and the second slurry is formed by keeping the rotation speed at 300rpm for 2h.

7. The method for preparing the LATP solid electrolyte with high ionic conductivity according to claim 1, characterized in that, In the high-temperature crystallization sintering of the second precursor, and cooling to obtain the first powder, the second precursor is heated to a first specified temperature at a first heating rate, and then cooled to room temperature after keeping the temperature for 30min, the first heating rate is at least 2℃ / min and at most 3℃ / min, and the first specified temperature is at least 950℃ and at most 1000℃.

8. The method of producing a high-ionic-conductivity LATP solid-state electrolyte according to any one of claims 1 to 7, characterized by, In the mixing of Li3PO4 and the first powder, and then mixing and drying by ball milling to obtain the second powder, the mass of Li3PO4 is at least 1wt% and at most 3wt%.

9. The method for preparing the LATP solid electrolyte with high ionic conductivity according to claim 8, characterized in that, The ball milling comprises ethanol wet ball milling, the ratio of material to ball is 1:10, and the third slurry is formed by keeping the specified rotation speed for the specified time, the specified rotation speed is at least 300rpm and at most 600rpm, and the specified time is at least 3h and at most 6h.

10. The method for preparing the LATP solid electrolyte with high ionic conductivity according to claim 1, characterized in that, In the high-temperature crystallization sintering of the second powder to obtain the LATP solid-state electrolyte, the second powder is heated to a second specified temperature at a second heating rate, and then crystallized after keeping the temperature, the second heating rate is at least 2℃ / min and at most 3℃ / min, and the second specified temperature is at least 750℃ and at most 800℃.

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