Solid electrolyte titanium aluminum lithium phosphate precursor, and preparation method therefor and the use thereof

Abstract

A solid electrolyte titanium aluminum lithium phosphate precursor, which comprises lithium, aluminum, titanium, oxygen, hydrogen and phosphorus. In an XRD pattern of the solid electrolyte titanium aluminum lithium phosphate precursor, the peak intensity ratio of a first strong diffraction peak to a second strong diffraction peak is 0.5-2.0, and the full width at half-maximum of the first strong diffraction peak and that of the second strong diffraction peak are respectively independently in the range of 0.3-0.8°; and the peak position of the first strong diffraction peak is in the range of 26.5-27.5°, and the peak position of the second strong diffraction peak is in the range of 27.5-28.5°. Titanium aluminum lithium phosphate precursor particles having a primary particle size of 5-30 nm can be directly used for the surface coating of a positive electrode material, and can be converted into nano titanium aluminum lithium phosphate merely by means of simple calcination.

Description

A solid-state electrolyte lithium aluminum titanium phosphate precursor, a preparation method thereof and application thereof TECHNICAL FIELD

[0001] The application belongs to the technical field of batteries, and relates to a solid-state electrolyte lithium aluminum titanium phosphate precursor, a preparation method thereof and application thereof. BACKGROUND

[0002] Currently, mainstream liquid lithium ion battery technology has problems in safety and energy density, and solid-state lithium ion batteries are considered to be able to overcome the defects of liquid batteries. As the basis and core material for the conversion of liquid lithium ion batteries to solid-state / solid-liquid hybrid lithium ion batteries, solid-state electrolytes determine the development of solid-state lithium ion batteries. Solid-state electrolytes for lithium ion batteries can be mainly divided into three categories: polymers, sulfides and oxides. In the oxide solid-state electrolyte system, NASICON (sodium fast ion conductor) type representative material lithium aluminum titanium phosphate Li 1+x Al x Ti 2-x (PO4)3(LATP, x = 0-0.5) is considered to be one of the most promising lithium fast ion conductors due to its high room temperature ionic conductivity (close to the level of commercial organic electrolyte), wide electrochemical window, high chemical stability and thermal stability.

[0003] For different application occasions, sometimes the particle size of the solid-state electrolyte needs to be fine and uniform and controllable, such as positive electrode surface coating, ion-electron composite conductive agent, etc. The methods for preparing LATP mainly include high-temperature solid-phase method, coprecipitation method and sol-gel method, etc. These methods all need high-temperature calcination in the final stage to obtain the final product LATP, resulting in large particle size of the prepared LATP and different degrees of agglomeration. Mechanical ball milling or sand milling is needed to obtain nano-sized (usually >100 nm) LATP. However, the powder after drying by ball milling or sand milling is also easy to agglomerate and block, which hinders the industrialization process of the LATP solid-state electrolyte. In addition, long-time grinding reduces the production efficiency, occupies the grinding equipment, easily causes crystal defects in the LATP particles, and introduces grinding medium impurities.

[0004] As mentioned in CN111740167A: mixing raw materials including titanium-containing compounds, organic solvents, mixed solvents, lithium source compounds, aluminum source compounds, and phosphorus source compounds to obtain a reaction precursor solution; heating the reaction precursor solution to obtain a precipitate, then pre-decomposing and calcining the precipitate to obtain nano-sized lithium aluminum titanium phosphate solid-state electrolyte. This method can controllably prepare nano-sized lithium aluminum titanium phosphate solid-state electrolyte with a size in the range of 20-100 nm in large quantities, but it needs to use organic solvents to dissolve titanium sources, which has problems of flammability, explosion, and organic waste liquid discharge, and the production cost is high; ammonia-containing substances are often used in the reaction process, which also causes difficulties in wastewater treatment. At the same time, the particle size of the nano-sized lithium aluminum titanium phosphate solid-state electrolyte material synthesized by low-pressure solvothermal method is distributed in the range of 20-100 nm. Whether this material is calcined at 800°C for 6h is questionable, because the product synthesized by low-pressure solvothermal method needs to be heated and pre-decomposed at a temperature of 500-800°C for 2-6h and calcined at a temperature of 800-1100°C for 6-12h to obtain it.

[0005] As disclosed in CN114804052A, a titanium aluminum phosphate precursor material contains aluminum elements, titanium elements, phosphorus elements, and oxygen elements. The precursor material is prepared by a solid phase sintering method. The XRD pattern of the precursor material has characteristic diffraction peaks at 2θ angles of 22°, 25°, and 27°. The precursor material does not contain Li element, and lithium source needs to be added during later calcination. At the same time, high-temperature calcination at 1400°C is energy-consuming, and the obtained material has a particle size of several or even ten microns, making it difficult to prepare small-particle-size lithium aluminum titanium phosphate materials.

[0006] As disclosed in CN111233458A, AlOOH precursor is first prepared by a liquid phase method, then mixed with lithium salt, titanium salt, and phosphorus salt according to the target stoichiometric ratio, and then ball milled, pre-fired, and sintered to form a lithium aluminum titanium phosphate solid electrolyte material. The prepared precursor is a mixture, and the particle size of the lithium aluminum titanium phosphate material prepared therefrom is >1 μm.

[0007] As disclosed in CN114914528A, a lithium aluminum titanium phosphate solid-state electrolyte, its preparation method and application are disclosed. Inexpensive and readily available inorganic salts are used as raw materials to prepare high-quality lithium aluminum titanium phosphate materials. However, this scheme uses a large amount of hydrogen peroxide and ammonia water, which has safety and environmental problems, and the particle size of the lithium aluminum titanium phosphate cannot be controlled.

[0008] As in CN115458804A, the raw materials are configured according to the stoichiometric ratio of lithium aluminum titanium phosphate, the precipitate is prepared, and the precipitate is washed. Water is used as the solvent in the preparation of the precipitate. The washed precipitate is configured into a suspension after being added with water, and then is moved into a sealed pressure container. The suspension is reacted at a certain temperature for a period of time. Then, the reacted material is dried to obtain a precursor powder. The precursor powder is heat-treated to obtain a solid-state electrolyte lithium aluminum titanium phosphate. However, one or more of ammonium dihydrogen phosphate and diammonium hydrogen phosphate is used as a phosphorus source, which involves ammonia-nitrogen wastewater discharge, increases the difficulty of wastewater disposal, pollutes the natural environment, and uses an alkaline solution to neutralize a mixed salt solution containing an aluminum source, a titanium source, and a phosphorus source to form a precipitate, which is then washed with water, which is easy to cause incomplete washing of impurity ions.

[0009] CN117525359A discloses a fast ion conductor coated high-voltage high-specific capacity lithium cobaltate positive electrode and a preparation method. In the preparation method, LATP is weighed and added to a beaker, deionized water is added, and a constant-temperature heating magnetic stirrer is stirred. The LATP is dispersed in the deionized water to form a hydrosol. The corresponding mass of high-voltage lithium cobaltate powder is weighed and added to the hydrosol of the LATP. The mixture is stirred and heated, and the deionized water is fully evaporated by constant-temperature stirring. The remaining mixed powder after evaporation is dried in an oven, fully ground in an agate mortar, transferred to a muffle furnace for sintering, heated, naturally cooled, and then ground again to obtain the final product. The use of LATP for surface coating of the lithium cobaltate positive electrode improves the performance of the lithium ion battery coated with the lithium cobaltate positive electrode by LATP. However, the use of the liquid coating method may not guarantee the uniformity of the coating.

[0010] It can be seen that the nano lithium aluminum titanium phosphate material has a large primary particle size and is prone to agglomeration and clumping, which is not conducive to achieving thin and uniform surface coating or uniform mixing. In the prior art, organic titanium sources, organic aluminum sources, and organic solvents are mostly used as reactants, which are high in raw material cost and flammable and explosive. In addition, there is organic matter emission during the reaction process, which is difficult to recover and process. In the scheme using inorganic salts as raw materials, a large amount of hydrogen peroxide and ammonia water are used as raw materials, which is not conducive to environmental protection and safety, and it is difficult to prepare nano lithium aluminum titanium phosphate materials with a particle size of less than 100 nm in industrial scale.

[0011] Based on the above research, the present application provides a solid-state electrolyte lithium aluminum titanium phosphate precursor. The precursor has a small particle size, uniform size distribution, is easy to disperse, and can form LATP after calcination. Therefore, the precursor can be used as a coating material to replace LATP for surface coating of positive electrode materials, which plays a positive role in improving the cycle stability of the positive electrode materials. SUMMARY

[0012] The application provides a solid-state electrolyte lithium aluminum titanium phosphate precursor and a preparation method and application thereof. The solid-state electrolyte lithium aluminum titanium phosphate precursor has specific strong diffraction peaks, specific peak intensity ratios and half-widths of the strong diffraction peaks, and can be easily dispersed due to small particle size and uniform size distribution. After calcination, the solid-state electrolyte lithium aluminum titanium phosphate precursor can form LATP, and thus can be directly used as a coating material for replacing LATP to coat the surface of a positive electrode material, thereby improving the performance of the positive electrode material.

[0013] In a first aspect, the application provides a solid-state electrolyte lithium aluminum titanium phosphate precursor, which comprises lithium, aluminum, titanium, oxygen, hydrogen and phosphorus.

[0014] In the XRD spectrum of the solid-state electrolyte lithium aluminum titanium phosphate precursor, the peak intensity ratio of the first strong diffraction peak to the second strong diffraction peak is 0.5-2.0, and the half-widths of the first strong diffraction peak and the second strong diffraction peak are independently 0.3-0.8°.

[0015] The peak position of the first strong diffraction peak is in the range of 26.5-27.5°, and the peak position of the second strong diffraction peak is in the range of 27.5-28.5°.

[0016] The solid-state electrolyte lithium aluminum titanium phosphate precursor described in the application contains Li, Al, Ti, O, H and P elements, and in the XRD spectrum thereof, the peak intensity ratio and the half-width of the first strong diffraction peak to the second strong diffraction peak are in a specific range, which is a new material different from LATP. The solid-state electrolyte lithium aluminum titanium phosphate precursor described in the application only needs to be simply calcined to be converted into nano lithium aluminum titanium phosphate. The size of the generated solid-state electrolyte lithium aluminum titanium phosphate precursor is controllable in the range of 30 nm to several hundred nm according to the calcination conditions. At the same time, the solid-state electrolyte lithium aluminum titanium phosphate precursor described in the application can be directly used for coating a positive electrode material, and after calcination, a positive electrode material with a relatively thin coating layer can be obtained.

[0017] The half-width described in the application refers to the peak width at half the peak height.

[0018] The peak intensity ratio of the first strong diffraction peak to the second strong diffraction peak is 0.5-2.0, for example, it can be 0.5, 0.7, 0.9, 1.1, 1.3, 1.5, 1.7 or 2.0, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0019] The half-widths of the first strong diffraction peak and the second strong diffraction peak are independently in the range of 0.3-0.8°, for example, they can be 0.3°, 0.4°, 0.5°, 0.6°, 0.7° or 0.8°, but are not limited to the listed values, and other values not listed in the value range are also applicable.

[0020] The peak position of the first strong diffraction peak is in the range of 26.5-27.5°, for example, can be 26.5°, 26.7°, 26.9°, 27.1°, 27.3° or 27.5°, the peak position of the second strong diffraction peak is in the range of 27.5-28.5°, for example, can be 27.5°, 27.7°, 27.9°, 28.1°, 28.3° or 28.5°, but not limited to the listed values, other values not listed in the value range are also applicable.

[0021] Preferably, the primary particle size of the solid-state electrolyte lithium aluminum titanium phosphate precursor is 5-30 nm, for example, can be 5 nm, 10 nm, 15 nm, 20 nm, 25 nm or 30 nm, the specific surface area is 60-150 m 2 / g, for example, can be 60 m 2 / g, 70 m 2 / g, 80 m 2 / g, 90 m 2 / g, 100 m 2 / g, 110 m 2 / g, 120 m 2 / g, 130 m 2 / g, 140 m 2 / g or 150 m 2 / g, but not limited to the listed values, other values not listed in the value range are also applicable.

[0022] The solid-state electrolyte lithium aluminum titanium phosphate precursor described in the present application has small particle size, uniform size distribution, is easy to disperse, and can be converted into nano lithium aluminum titanium phosphate by simple calcination. The particle size of the generated lithium aluminum titanium phosphate is controllable in the range of 30 nm to several hundred nm according to the calcination conditions, and the obtained lithium aluminum titanium phosphate particles can be used as a nano solid electrolyte material for solid or semi-solid lithium ion batteries, or for coating of positive electrode materials, ceramic separator coating or polymer-oxide composite solid electrolyte materials.

[0023] Preferably, in the solid-state electrolyte lithium aluminum titanium phosphate precursor, the molar ratio of lithium element, aluminum element, titanium element and phosphorus element is (1+x):x:(2-x):3, wherein x is 0-0.5, but not including 0, for example, can be 0.1, 0.2, 0.3, 0.4 or 0.5, but not limited to the listed values, other values not listed in the value range are also applicable.

[0024] Preferably, in the XRD spectrum of the solid-state electrolyte lithium aluminum titanium phosphate precursor, there are three additional diffraction peaks at 2θ of 16.8-17.3°, for example, 16.8°, 17.0°, 17.2° or 17.3°; at 2θ of 18.3-18.9°, for example, 18.3°, 18.5°, 18.7° or 18.9°; and at 2θ of 24.5-25.0°, for example, 24.5°, 24.7°, 24.9° or 25.0°, respectively.

[0025] In the XRD spectrum of the solid-state electrolyte lithium aluminum titanium phosphate precursor described in the present application, there are three additional diffraction peaks at 2θ of 16.8-17.3°, 18.3-18.9° and 24.5-25.0°, respectively.

[0026] In a second aspect, the present application provides a preparation method of the solid-state electrolyte lithium aluminum titanium phosphate precursor according to the first aspect, which comprises the following steps:

[0027] (1) mixing a titanium source, an aluminum source, water and phosphoric acid to obtain a gel-like substance, washing and drying the gel-like substance to obtain a solid substance;

[0028] (2) mixing and hydrothermally reacting the solid substance of step (1), a lithium source and water to obtain a hydrothermal product, and washing and drying the hydrothermal product to obtain the solid-state electrolyte lithium aluminum titanium phosphate precursor.

[0029] In the present application, the titanium source, the aluminum source solution and the phosphoric acid are reacted to form a semi-solid gel, which can realize uniform mixing of Ti / Al / P and obtain a highly dispersed Ti / Al / P mixture. After the white solid substance after washing and drying is fully mixed with a lithium source-containing aqueous solution, a hydrothermal reaction is performed, and an ultra-fine lithium aluminum titanium phosphate precursor with good crystallinity and a particle size in the range of 5-30 nm can be obtained.

[0030] In the present application, no organic solvent is used, and the reaction is directly performed using phosphoric acid, thereby avoiding the generation of organic waste liquid and ammonia-nitrogen wastewater.

[0031] Preferably, the mixing of step (1) comprises first mixing the titanium source, the aluminum source and water to obtain a mixed source solution, and then mixing the mixed source solution with the phosphoric acid.

[0032] Preferably, in the mixed source solution, the total metal ion molar concentration is 1-3 mol / L, for example, 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L or 3 mol / L, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0033] The total metal ion molar concentration in the mixed source solution of the titanium source and the aluminum source reacting with phosphoric acid affects the washing efficiency of the Ti / Al / P mixture, and also affects the particle size, morphology, phase structure, and other properties of the product. If the total metal ion molar concentration of titanium and aluminum is too large, the powder particle size is large, the morphology structure is more compact, and the crystallization degree is too high. If the total metal ion molar concentration of titanium and aluminum is too small, the amount of deionized water is too large, the washing treatment time is increased, and the production efficiency is reduced.

[0034] Preferably, the mass concentration of the phosphoric acid is 30-85 wt%, for example, it can be 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, or 85 wt%, but is not limited to the listed values, and other values not listed within the value range are also applicable.

[0035] Preferably, the titanium source in step (1) includes titanium tetrachloride.

[0036] Preferably, the aluminum source in step (1) includes aluminum chloride hexahydrate and / or aluminum hydroxide.

[0037] All raw materials used in the present application do not use organic matter, and are inorganic salts or inorganic acids that can be obtained at a low cost, have no ammonia nitrogen emissions, effectively save costs, are safe and environmentally friendly, and can facilitate industrial production.

[0038] Preferably, the temperature of the hydrothermal reaction in step (2) is 130-200℃, for example, it can be 130℃, 150℃, 170℃, 190℃, or 200℃, and the time is 6-24h, for example, it can be 6h, 10h, 14h, 18h, 22h, or 24h, but is not limited to the listed values, and other values not listed within the value range are also applicable.

[0039] The temperature of the hydrothermal reaction in the present application affects the size, morphology, phase composition, and crystallization degree of the product, and if the temperature of the hydrothermal reaction is too low, the product has a cluster body structure composed of nano-flake-shaped particles, the phase composition is unchanged or has more impurities, and the crystallization is poor. If the temperature of the hydrothermal reaction is too high, the particle size of the product is larger, and impurities may also be present.

[0040] Preferably, in the hydrothermal reaction system in step (2), the molar ratio of lithium, aluminum, titanium, and phosphorus is (1+x):(2+x):(2-x):3, for example, it can be (1+x):(2+x):(2-x):3 or (2+x):(2+x):(2-x):3, wherein x is 0-0.5, but does not include 0, for example, it can be 0.1, 0.2, 0.3, 0.4, or 0.5, but is not limited to the listed values, and other values not listed within the value range are also applicable.

[0041] Preferably, the mixing in step (2) comprises mixing the lithium source and water first to obtain a lithium source solution, and then mixing the lithium source solution with the solid substance.

[0042] Preferably, the mass concentration of the lithium source solution is 40-200 g / L, for example, can be 40 g / L, 100 g / L, 150 g / L or 200 g / L, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0043] The mass concentration of the lithium source solution in the hydrothermal reaction of the present application can affect the yield of the hydrothermal product, the particle size of the powder and the crystallinity, etc. If the mass concentration is too low, the yield of the hydrothermal product is low and the crystallinity is low; if the mass concentration is too high, the particle size of the powder is prone to grow.

[0044] Preferably, the lithium source in step (2) comprises lithium hydroxide monohydrate.

[0045] In a third aspect, the present application provides a solid-state electrolyte lithium aluminum titanium phosphate, which is obtained by calcining the solid-state electrolyte lithium aluminum titanium phosphate precursor according to the first aspect.

[0046] Preferably, the calcination temperature is 400-900℃, for example, can be 400℃, 450℃, 500℃, 550℃, 600℃, 650℃, 700℃, 750℃, 800℃, 850℃ or 900℃, preferably 750-900℃, and the time is 1-4 h, for example, can be 1 h, 2 h, 3 h or 4 h, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0047] According to the condition control, the present application can prepare a porous structure of pure-phase lithium aluminum titanium phosphate nanoparticles with a particle size of 30 nm to several hundred nm, and then the calcined product is ground to obtain lithium aluminum titanium phosphate particles with a particle size of 30 nm to several hundred nm with high dispersity, for example, to obtain lithium aluminum titanium phosphate with a primary particle size of <100 nm.

[0048] When the solid-state electrolyte lithium aluminum titanium phosphate is prepared by calcining the solid-state electrolyte lithium aluminum titanium phosphate precursor according to the present application, if the calcination temperature is too low, the obtained product is not pure; if the temperature is too high, the particles grow too large.

[0049] In a fourth aspect, the present application provides a positive electrode material, the surface of which is coated with a coating layer, and the positive electrode material is obtained by mixing the solid-state electrolyte lithium aluminum titanium phosphate precursor according to the first aspect with an uncoated positive electrode material and then sintering.

[0050] The application directly uses the solid-state electrolyte lithium aluminum titanium phosphate precursor to coat, and a thinner and more uniform coating layer can be obtained; and the surface coating layer of the positive electrode material contains Li elements, Al elements, Ti elements and phosphate groups, etc. Since the lithium aluminum titanium phosphate may react with the surface of the positive electrode material during sintering, the substance finally coated on the surface is not necessarily lithium aluminum titanium phosphate.

[0051] Preferably, the thickness of the coating layer on the surface of the positive electrode material is <10 nm, for example, it can be 9 nm, 8 nm, 7 nm, 6 nm or 5 nm, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0052] Preferably, the solid-state electrolyte lithium aluminum titanium phosphate precursor accounts for 0.1-0.5wt% of the total mass of the solid-state electrolyte lithium aluminum titanium phosphate precursor and the uncoated positive electrode material, for example, it can be 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt% or 0.5wt%, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0053] Preferably, the sintering temperature is 400-900℃, for example, it can be 400℃, 600℃, 800℃ or 900℃, and the time is 1-4h, for example, it can be 1h, 2h, 3h or 4h, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0054] Preferably, the positive electrode material includes lithium cobaltate, spinel lithium manganate, ternary material or any one or combination of at least two of nickel cobalt manganate with an average particle size >2μm.

[0055] Compared with the prior art, the application has the following beneficial effects:

[0056] (1) The application uses a mixed aqueous solution of a titanium source such as titanium tetrachloride and an aluminum source to react with phosphoric acid to form a semi-solid gel, which can realize uniform mixing of Ti / Al / P and obtain a highly dispersed Ti / Al / P mixture. After washing and drying the white substance, it is fully mixed with a lithium source aqueous solution, and then hydrothermally reacted at a certain temperature for a certain time, to obtain a superfine lithium aluminum titanium phosphate precursor with good crystallinity and a particle size of 5-30nm;

[0057] (2) The application can mix the superfine lithium aluminum titanium phosphate precursor with the positive electrode material of the lithium ion battery through a dry or wet coating process to form a coating layer on the surface of the positive electrode, and then perform a simple calcination to obtain a positive electrode material with a lithium aluminum titanium phosphate coating layer with a thickness <10nm. Thin layer coating can stabilize the structure of the positive electrode material, reduce the positive electrode / electrolyte interface side reaction and improve the performance of the lithium ion battery on the basis of ensuring the original performance of the battery.

[0058] (3) The ultrafine lithium aluminum titanium phosphate precursor particles are calcined to obtain high-purity solid-state electrolyte lithium aluminum titanium phosphate. By controlling the calcination temperature and time, lithium aluminum titanium phosphate particles with different particle sizes can be obtained, which can be applied to different scenarios such as surface coating of lithium ion battery positive electrode materials, positive electrode slurry addition, and solid-state lithium ion battery preparation.

[0059] (4) The preparation method of the solid-state electrolyte lithium aluminum titanium phosphate precursor does not use organic matter, does not introduce ammonia nitrogen, and does not use strong oxidizing agents. The raw materials are simple and easy to obtain, the preparation method is controllable and easy to operate, the reaction conditions are mild, and industrial production can be realized.

[0060] (5) The preparation method is convenient for formula control and doping of lithium aluminum titanium phosphate, and further optimizes the performance. BRIEF DESCRIPTION OF DRAWINGS

[0061] FIG. 1 is an XRD diagram of the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in Example 1 of the present application;

[0062] FIG. 2 is an SEM diagram of the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in Example 1 of the present application under a 2 pm scale;

[0063] FIG. 3 is an SEM diagram of the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in Example 1 of the present application under a 1 pm scale;

[0064] FIG. 4 is a particle size distribution diagram of the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in Example 1 of the present application;

[0065] FIG. 5 is an SEM diagram of the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in Example 1 of the present application as a coating material coated on the positive electrode material under a 2 pm scale;

[0066] FIG. 6 is an SEM diagram of the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in Example 1 of the present application as a coating material coated on the positive electrode material under a 1 pm scale;

[0067] FIG. 7 is an SEM diagram of the solid-state electrolyte lithium aluminum titanium phosphate obtained by calcining the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in Example 1 of the present application at 800°C for 2h;

[0068] FIG. 8 is an SEM diagram of the solid-state electrolyte lithium aluminum titanium phosphate obtained by calcining the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in Example 1 of the present application at 900°C for 2h;

[0069] FIG. 9 is a thermogravimetric diagram of the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in Example 1 of the present application;

[0070] FIG. 10 is an infrared diagram of the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in Example 1 of the present application;

[0071] Figure 11 is an SEM image of the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in Example 4 of the present application;

[0072] Figure 12 is an XRD image of the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in Example 4 of the present application;

[0073] Figure 13 is an SEM image of the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in Example 5 of the present application;

[0074] Figure 14 is an XRD image of the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in Example 5 of the present application;

[0075] Figure 15 is an SEM image of the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in Example 6 of the present application;

[0076] Figure 16 is an SEM image of the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in Example 10 of the present application;

[0077] Figure 17 is an XRD image of the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in Example 10 of the present application;

[0078] Figure 18 is an XRD image of the solid-state electrolyte lithium aluminum titanium phosphate obtained in Example 1 of the present application;

[0079] Figure 19 is an XRD image of the solid-state electrolyte lithium aluminum titanium phosphate precursor, the solid-state electrolyte lithium aluminum titanium phosphate, and the standard XRD image of lithium aluminum titanium phosphate obtained in Example 1 of the present application. DETAILED DESCRIPTION

[0080] The technical solutions of the present application will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the present application and should not be regarded as specific limitations to the present application.

[0081] Example 1

[0082] The present embodiment provides a solid-state electrolyte lithium aluminum titanium phosphate precursor, which comprises lithium element, aluminum element, titanium element and phosphorus element in a molar ratio of 1.3:0.3:1.7:3, and the XRD image of the solid-state electrolyte lithium aluminum titanium phosphate precursor is shown in Figure 1. There are a first strong characteristic diffraction peak and a second strong characteristic diffraction peak in the XRD image, and three weak characteristic diffraction peaks at 17.1°, 18.6° and 24.8°.

[0083] The SEM image of the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in the embodiment under a 2 pm scale is shown in FIG. 2, the SEM image under a 1 pm scale is shown in FIG. 3, and the particle size distribution diagram is shown in FIG. 4. As can be seen from FIGS. 2-4, the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in the embodiment has a small particle size, which can reach 5-30 nm.

[0084] The thermogravimetric diagram of the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in the embodiment is shown in FIG. 9. The loss on ignition of the solid-state electrolyte lithium aluminum titanium phosphate precursor at 820℃ is between 3% and 13.58%. As can be seen from FIG. 9, the mass gradually decreases when the temperature is increased from 30℃ to about 400℃ under air atmosphere, the mass fluctuates but the overall trend is downward when the temperature is continuously increased to 650℃, and then the mass tends to be stable.

[0085] The infrared diagram of the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in the embodiment is shown in FIG. 10. The -OH absorption peaks at 3396 cm -1 and 1654 cm -1 may be caused by adsorbed water or crystal water. In combination with the loss on ignition and the thermogravimetric data, it is speculated that the solid-state electrolyte lithium aluminum titanium phosphate precursor may contain a certain amount of crystal water.

[0086] The preparation method of the solid-state electrolyte lithium aluminum titanium phosphate precursor includes the following steps:

[0087] Lithium hydroxide monohydrate, aluminum chloride hexahydrate, titanium tetrachloride and phosphoric acid (with a mass concentration of 85%) are weighed according to the molar ratio Li:Al:Ti:P = 1.43:0.3:1.7:3. The aluminum titanium mixed salt aqueous solution with a total molar concentration of 1.6 mol / L is prepared by mixing aluminum chloride hexahydrate and titanium tetrachloride. The semi-solid gel is formed after mixing the aluminum titanium mixed salt aqueous solution with phosphoric acid. The obtained gel is washed with deionized water and repeatedly filtered to neutral, and then dried in a blast drying oven at 90℃ to obtain a white solid. Lithium hydroxide monohydrate is prepared into a lithium hydroxide solution with a mass concentration of 80 g / L. After grinding the white solid, the lithium hydroxide solution is mixed with the white solid, and then transferred into a 250 mL sealed reaction kettle. The hydrothermal reaction is carried out at 130℃ for 18 h. After the reaction kettle is cooled to room temperature, the hydrothermal product is taken out, washed with deionized water to neutral, and dried at 90℃ to obtain the lithium aluminum titanium phosphate precursor.

[0088] The embodiment also provides a positive electrode material coated with lithium aluminum titanium phosphate, and the preparation method of the positive electrode material includes the following steps:

[0089] The lithium cobaltate powder is loaded into a special mixing tank of a high-speed mixer, 1% of the total mass percentage of lithium titanium aluminum phosphate precursor powder is added to the lithium cobaltate and lithium titanium aluminum phosphate precursor, high-speed mixing is performed, the rotating speed is 2000 rpm, the mixing time is 3 min, and a dry mixing material is obtained. The dry mixing material is calcined at 800 ℃ for 2 h to obtain lithium cobaltate coated with lithium titanium aluminum phosphate. The SEM image of the solid-state electrolyte lithium titanium aluminum phosphate precursor obtained in the example as a coating material for coating the positive electrode material is shown in FIG. 5 at a scale of 2 μm, and the SEM image is shown in FIG. 6 at a scale of 1 μm.

[0090] The example also provides a solid-state electrolyte lithium titanium aluminum phosphate, and a preparation method of the solid-state electrolyte lithium titanium aluminum phosphate includes the following steps:

[0091] The solid-state electrolyte lithium titanium aluminum phosphate precursor is calcined at 800 ℃ for 2 h to obtain the SEM image of the solid-state electrolyte lithium titanium aluminum phosphate shown in FIG. 7, and the XRD image of the solid-state electrolyte lithium titanium aluminum phosphate is shown in FIG. 18. The XRD images of the solid-state electrolyte lithium titanium aluminum phosphate precursor, the solid-state electrolyte lithium titanium aluminum phosphate, and the lithium titanium aluminum phosphate standard XRD image are shown in FIG. 19. As shown in FIG. 19, the diffraction peak positions of the solid-state electrolyte lithium titanium aluminum phosphate precursor and the solid-state electrolyte lithium titanium aluminum phosphate are different. The solid-state electrolyte lithium titanium aluminum phosphate corresponding to the standard spectrum can be obtained by calcining the solid-state electrolyte lithium titanium aluminum phosphate precursor.

[0092] The solid-state electrolyte lithium titanium aluminum phosphate obtained by calcining the solid-state electrolyte lithium titanium aluminum phosphate precursor at 900 ℃ for 2 h is shown in FIG. 8. As shown in FIGS. 7 and 8, the lithium titanium aluminum phosphate precursor is used as the surface coating material of the positive electrode. Because the particle size is small, uniform, and easy to disperse, it is beneficial to achieve thin and uniform coating on the surface of the positive electrode, and the amount is more advantageous than using the larger particle size lithium titanium aluminum phosphate nanoparticles obtained by calcination and then coating.

[0093] Example 2

[0094] The example provides a solid-state electrolyte lithium titanium aluminum phosphate precursor, which includes lithium, aluminum, titanium, and phosphorus in a molar ratio of 1.5:0.5:1.5:3. The XRD spectrum of the solid-state electrolyte lithium titanium aluminum phosphate precursor includes a first strong characteristic diffraction peak and a second strong characteristic diffraction peak, and three weak characteristic diffraction peaks at 16.8°, 18.3°, and 24.5°.

[0095] The preparation method of the solid-state electrolyte lithium titanium aluminum phosphate precursor includes the following steps:

[0096] Lithium hydroxide monohydrate, aluminum chloride hexahydrate, titanium tetrachloride and phosphoric acid with a mass concentration of 30wt% were weighed according to the molar ratio of Li:Al:Ti:P = 2:0.5:1.5:3, and the aluminum chloride hexahydrate and titanium tetrachloride were prepared into an aluminum-titanium mixed salt aqueous solution with a total molar concentration of 1mol / L. After mixing the aluminum-titanium mixed salt aqueous solution with the phosphoric acid, a semi-solid gel was formed. The obtained gel was washed with deionized water and repeatedly filtered to neutral, and was placed in a blast drying oven for drying treatment at 90℃ to obtain a white solid. Lithium hydroxide monohydrate was prepared into a lithium hydroxide solution with a mass concentration of 40g / L. After grinding the white solid, the white solid was mixed with the lithium hydroxide solution and transferred to a 250mL sealed reaction kettle. The reaction kettle was subjected to hydrothermal reaction at 130℃ for 24h. After the reaction kettle was cooled to room temperature, the hydrothermal product was taken out, washed with deionized water to neutral, and dried at 90℃ to obtain a titanium aluminum lithium phosphate precursor.

[0097] The present embodiment also provides a solid-state electrolyte lithium aluminum titanium phosphate, and a preparation method of the solid-state electrolyte lithium aluminum titanium phosphate includes the following steps:

[0098] The solid-state electrolyte lithium aluminum titanium phosphate precursor described in the present embodiment is calcined at 750℃ for 4h to obtain the solid-state electrolyte lithium aluminum titanium phosphate.

[0099] Example 3

[0100] The present embodiment provides a solid-state electrolyte lithium aluminum titanium phosphate precursor, which includes lithium element, aluminum element, titanium element and phosphorus element with a molar ratio of 1.1:0.1:1.9:3. The XRD pattern of the solid-state electrolyte lithium aluminum titanium phosphate precursor includes a first strong characteristic diffraction peak and a second strong characteristic diffraction peak, and three weak characteristic diffraction peaks at 17.3°, 18.9° and 25.0°.

[0101] The preparation method of the solid-state electrolyte lithium aluminum titanium phosphate precursor includes the following steps:

[0102] Lithium hydroxide monohydrate, aluminum chloride hexahydrate, titanium tetrachloride and phosphoric acid with a mass concentration of 50wt% were weighed according to the molar ratio of Li:Al:Ti:P = 1.1:0.1:1.9:3, and the aluminum titanium mixed salt aqueous solution with a total molar concentration of 3mol / L was prepared by mixing aluminum chloride hexahydrate and titanium tetrachloride. After mixing the aluminum titanium mixed salt aqueous solution with the phosphoric acid, a semi-solid gel was formed, and the obtained gel was washed with deionized water and repeatedly filtered to be neutral, and then was placed in a blast drying oven for drying treatment at 90℃ to obtain a white solid. Lithium hydroxide monohydrate was prepared into a lithium hydroxide solution with a mass concentration of 200g / L, and the white solid was ground and mixed with the lithium hydroxide solution, and then was transferred into a 250mL sealed reaction kettle, and was subjected to hydrothermal reaction at 200℃ for 6h. After the reaction kettle was cooled to room temperature, the hydrothermal product was taken out, washed with deionized water to be neutral, and dried at 90℃ to obtain a titanium aluminum lithium phosphate precursor.

[0103] The present embodiment also provides a solid-state electrolyte lithium aluminum titanium phosphate, and a preparation method of the solid-state electrolyte lithium aluminum titanium phosphate comprises the following steps:

[0104] The solid-state electrolyte lithium aluminum titanium phosphate precursor in the present embodiment is calcined at 900℃ for 1h to obtain the solid-state electrolyte lithium aluminum titanium phosphate.

[0105] Example 4

[0106] The present embodiment provides a solid-state electrolyte lithium aluminum titanium phosphate precursor, which is the same as that in Example 1 except that the temperature of the hydrothermal reaction in the preparation method thereof is 150℃, and the mass concentration of the lithium hydroxide solution is 160g / L, so that the obtained solid-state electrolyte lithium aluminum titanium phosphate precursor is adaptively changed.

[0107] The SEM image of the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in the present embodiment is shown in FIG. 11, and the XRD image is shown in FIG. 12.

[0108] The present embodiment also provides a solid-state electrolyte lithium aluminum titanium phosphate, and a preparation method of the solid-state electrolyte lithium aluminum titanium phosphate comprises the following steps:

[0109] The solid-state electrolyte lithium aluminum titanium phosphate precursor in the present embodiment is calcined at 800℃ for 2h to obtain the solid-state electrolyte lithium aluminum titanium phosphate.

[0110] Example 5

[0111] The present embodiment provides a solid-state electrolyte lithium aluminum titanium phosphate precursor, which is the same as that in Example 1 except that the temperature of the hydrothermal reaction in the preparation method thereof is 150℃, and the mass concentration of the lithium hydroxide solution is 160g / L, so that the obtained solid-state electrolyte lithium aluminum titanium phosphate precursor is adaptively changed.

[0112] The SEM image of the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in the embodiment is shown in Figure 13, and the XRD image is shown in Figure 14.

[0113] The embodiment also provides a solid-state electrolyte lithium aluminum titanium phosphate, and a preparation method of the solid-state electrolyte lithium aluminum titanium phosphate comprises the following steps:

[0114] The solid-state electrolyte lithium aluminum titanium phosphate precursor in the embodiment is calcined at 800℃ for 2h to obtain the solid-state electrolyte lithium aluminum titanium phosphate.

[0115] Embodiment 6

[0116] The embodiment provides a solid-state electrolyte lithium aluminum titanium phosphate precursor, which is the same as that in Embodiment 1 except that the concentration of the aqueous mixed salt solution of aluminum and titanium in the preparation method is 2.4mol / L, so that the obtained solid-state electrolyte lithium aluminum titanium phosphate precursor is adaptable.

[0117] The SEM image of the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in the embodiment is shown in Figure 15.

[0118] The embodiment also provides a solid-state electrolyte lithium aluminum titanium phosphate, and a preparation method of the solid-state electrolyte lithium aluminum titanium phosphate comprises the following steps:

[0119] The solid-state electrolyte lithium aluminum titanium phosphate precursor in the embodiment is calcined at 800℃ for 2h to obtain the solid-state electrolyte lithium aluminum titanium phosphate.

[0120] Embodiment 7

[0121] The embodiment provides a solid-state electrolyte lithium aluminum titanium phosphate precursor, which is the same as that in Embodiment 1 except that the concentration of the aqueous mixed salt solution of aluminum and titanium in the preparation method is 0.5mol / L, so that the obtained solid-state electrolyte lithium aluminum titanium phosphate precursor is adaptable.

[0122] The embodiment also provides a solid-state electrolyte lithium aluminum titanium phosphate, and a preparation method of the solid-state electrolyte lithium aluminum titanium phosphate comprises the following steps:

[0123] The solid-state electrolyte lithium aluminum titanium phosphate precursor in the embodiment is calcined at 800℃ for 2h to obtain the solid-state electrolyte lithium aluminum titanium phosphate.

[0124] Embodiment 8

[0125] The embodiment provides a solid-state electrolyte lithium aluminum titanium phosphate precursor, which is the same as that in Embodiment 1 except that the concentration of the aqueous aluminum titanium mixed salt solution in the preparation method is 3.5 mol / L, so that the obtained solid-state electrolyte lithium aluminum titanium phosphate precursor is adaptable.

[0126] The embodiment further provides a solid-state electrolyte lithium aluminum titanium phosphate, and the preparation method of the solid-state electrolyte lithium aluminum titanium phosphate comprises the following steps.

[0127] The solid-state electrolyte lithium aluminum titanium phosphate precursor in the embodiment is calcined at 800 DEG C for 2h to obtain the solid-state electrolyte lithium aluminum titanium phosphate.

[0128] Embodiment 9

[0129] The embodiment provides a solid-state electrolyte lithium aluminum titanium phosphate precursor, which is the same as that in Embodiment 1 except that the temperature of the hydrothermal reaction in the preparation method is 220 DEG C, so that the obtained solid-state electrolyte lithium aluminum titanium phosphate precursor is adaptable.

[0130] The embodiment further provides a solid-state electrolyte lithium aluminum titanium phosphate, and the preparation method of the solid-state electrolyte lithium aluminum titanium phosphate comprises the following steps.

[0131] The solid-state electrolyte lithium aluminum titanium phosphate precursor in the embodiment is calcined at 800 DEG C for 2h to obtain the solid-state electrolyte lithium aluminum titanium phosphate.

[0132] Embodiment 10

[0133] The embodiment provides a solid-state electrolyte lithium aluminum titanium phosphate precursor, which is the same as that in Embodiment 1 except that the temperature of the hydrothermal reaction in the preparation method is 120 DEG C, so that the obtained solid-state electrolyte lithium aluminum titanium phosphate precursor is adaptable.

[0134] The SEM image of the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in the embodiment is shown in Figure 16, and the XRD image is shown in Figure 17.

[0135] The embodiment further provides a solid-state electrolyte lithium aluminum titanium phosphate, and the preparation method of the solid-state electrolyte lithium aluminum titanium phosphate comprises the following steps.

[0136] The solid-state electrolyte lithium aluminum titanium phosphate precursor in the embodiment is calcined at 800 DEG C for 2h to obtain the solid-state electrolyte lithium aluminum titanium phosphate.

[0137] Embodiment 11

[0138] The embodiment provides a solid-state electrolyte lithium aluminum titanium phosphate precursor, and a preparation method thereof, which are the same as those in the embodiment 1.

[0139] The embodiment further provides a solid-state electrolyte lithium aluminum titanium phosphate, and a preparation method thereof, which are the same as those in the embodiment 1 except that the temperature of the calcination is 650 DEG C.

[0140] Embodiment 12

[0141] The embodiment provides a solid-state electrolyte lithium aluminum titanium phosphate precursor, and a preparation method thereof, which are the same as those in the embodiment 1.

[0142] The embodiment further provides a solid-state electrolyte lithium aluminum titanium phosphate, and a preparation method thereof, which are the same as those in the embodiment 1 except that the temperature of the calcination is 1000 DEG C.

[0143] Comparative example 1

[0144] The comparative example provides a solid-state electrolyte lithium aluminum titanium phosphate precursor, and a preparation method thereof, which are the same as those in the embodiment 1 except that the lithium hydroxide solution, the aqueous solution of the mixed aluminum titanium salt and the phosphoric acid are mixed to perform a hydrothermal reaction, so that the obtained solid-state electrolyte lithium aluminum titanium phosphate precursor is changed in adaptability.

[0145] In the XRD spectrum of the solid-state electrolyte lithium aluminum titanium phosphate precursor obtained in the above embodiment and comparative example, the peak position, peak intensity ratio and half-height width of the first strong diffraction peak and the second strong diffraction peak, the primary particle size range of the solid-state electrolyte lithium aluminum titanium phosphate precursor and the primary particle size range of the obtained solid-state electrolyte lithium aluminum titanium phosphate are shown in Table 1.

[0146] Table 1

[0147] From Table 1, it can be seen that:

[0148] From the examples 1-3 and the comparative example 1, it can be seen that the application uses a mixed aqueous solution of titanium tetrachloride and an aluminum source to react with phosphoric acid, and then fully mixes with a lithium source aqueous solution to hydrothermally react, which can obtain a phosphoric acid titanium aluminum lithium precursor with good crystallinity and ultra-fine particle size. In the comparative example 1, the lithium source is reacted with the titanium source, the aluminum source and the phosphoric acid together, and then hydrothermally reacted, which can cause the particle size of the phosphoric acid titanium aluminum lithium precursor to be large. From the examples 1 and 4-10, combined with Figures 11-16, it can be seen that the temperature of the hydrothermal reaction, the mass concentration of the lithium hydroxide solution and the concentration of the aluminum-titanium mixed aqueous solution will affect the primary particle size of the product, especially the temperature of the hydrothermal reaction, which will greatly affect the particle size of the phosphoric acid titanium aluminum lithium precursor. From the examples 1 and 11-12, it can be seen that when the solid-state electrolyte phosphoric acid titanium aluminum lithium precursor is used to prepare a solid-state electrolyte phosphoric acid titanium aluminum lithium, if the temperature is not within the preferred range, the purity or particle size of the obtained solid-state electrolyte phosphoric acid titanium aluminum lithium will be affected.

[0149] In summary, the application provides a solid-state electrolyte phosphoric acid titanium aluminum lithium precursor, a preparation method and application thereof. The preparation method can prepare phosphoric acid titanium aluminum lithium precursor particles with a primary particle size of 5-30 nm. The precursor particles only need to be simply calcined to be converted into nano-phosphoric acid titanium aluminum lithium, or be used in the coating of positive electrode materials, ceramic separator coating and polymer-oxide composite solid electrolyte materials.

[0150] The above only describes specific embodiments of the application, but the protection scope of the application is not limited thereto. It should be understood by those skilled in the art that any changes or replacements within the technical scope disclosed in the application can be easily thought of by those skilled in the art, and all fall within the protection scope and disclosure scope of the application.

Claims

1. A solid-state electrolyte lithium aluminum titanium phosphate precursor, comprising lithium element, aluminum element, titanium element, oxygen element, hydrogen element and phosphorus element; In an XRD spectrum of the solid-state electrolyte lithium aluminum titanium phosphate precursor, a peak intensity ratio of a first strong diffraction peak and a second strong diffraction peak is 0.5-2.0, and a half-height width of the first strong diffraction peak and the second strong diffraction peak ranges from 0.3 to 0.8° independently. The first strong diffraction peak is located in a range of 26.5-27.5°, and the second strong diffraction peak is located in a range of 27.5-28.5°.

2. The solid-state electrolyte lithium aluminum titanium phosphate precursor of claim 1, wherein, The primary particle size of the solid-state electrolyte lithium aluminum titanium phosphate precursor is 5-30 nm, and the specific surface area is 60-150 m 2 / g; In the solid-state electrolyte lithium aluminum titanium phosphate precursor, a molar ratio of the lithium element, the aluminum element, the titanium element and the phosphorus element is (1+x) : x : (2-x) : 3, wherein x is 0-0.5, but 0 is not included. In the XRD spectrum of the solid-state electrolyte lithium aluminum titanium phosphate precursor, diffraction peaks further exist at 2θ of 16.8-17.3°, 18.3-18.9° and 24.5-25.0° respectively. 3.A preparation method of the solid-state electrolyte lithium aluminum titanium phosphate precursor according to claim 1 or 2, comprising the following steps: (1) mixing a titanium source, an aluminum source, water and phosphoric acid to obtain a gel-like substance, washing and drying the gel-like substance to obtain a solid substance; (2) mixing and hydrothermally reacting the solid substance in step (1), a lithium source and water to obtain a hydrothermal product, and washing and drying the hydrothermal product to obtain the solid-state electrolyte lithium aluminum titanium phosphate precursor.

4. The production method according to claim 3, wherein The mixing in step (1) comprises mixing the titanium source, the aluminum source and water first to obtain a mixed source solution, and then mixing the mixed source solution with the phosphoric acid; In the mixed source solution, the total metal ion molar concentration is 1-3 mol / L; The mass concentration of the phosphoric acid is 30-85 wt.%.

5. The production process according to claim 3 or 4, wherein, The titanium source in step (1) comprises titanium tetrachloride; The aluminum source in step (1) comprises aluminum chloride hexahydrate and / or aluminum hydroxide.

6. The production method according to claim 3 or 4, wherein The temperature of the hydrothermal reaction in step (2) is 130-200 ℃, and the time is 6-24 h; In the hydrothermal reaction system in step (2), a molar ratio of the lithium element, the aluminum element, the titanium element and the phosphorus element is (1+x) - (2+x) : x : (2-x) : 3, wherein x is 0-0.5, but 0 is not included.

7. The production method according to claim 3 or 4, wherein The mixing in step (2) comprises mixing the lithium source and water first to obtain a lithium source solution, and then mixing the lithium source solution with the solid substance; The mass concentration of the lithium source solution is 40-200 g / L. 8.A solid-state electrolyte lithium aluminum titanium phosphate obtained by calcining the solid-state electrolyte lithium aluminum titanium phosphate precursor according to claim 1 or 2.

9. The solid-state electrolyte lithium aluminum titanium phosphate of claim 8, wherein, The temperature of the calcination is 400-900 ℃, and the time is 1-4 h. 10.A positive electrode material coated with a coating layer, obtained by mixing the solid-state electrolyte lithium aluminum titanium phosphate precursor according to claim 1 or 2 with an uncoated positive electrode material and sintering.

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