Preparation method of lithium-rich lithium titanium phosphate solid-state electrolyte and application thereof

Abstract

This invention belongs to the field of all-solid-state lithium metal batteries and discloses a method for preparing a lithium-rich titanium phosphate lithium solid electrolyte and its application. The preparation method of this invention has the advantages of simplicity, energy saving, and suitability for large-scale production. By optimizing precursor preparation and reaction conditions, the synthesis temperature is significantly reduced and the reaction cycle is shortened. The resulting electrolyte material has a pure phase and excellent ionic conductivity, effectively solving the key challenges in the practical preparation of this material. This method is of great value in promoting the industrial application of high-safety, high-energy-density solid-state lithium metal batteries. The solid electrolyte powder prepared by this method is in the form of nanoparticles with a narrow particle size distribution, and exhibits a bulk room-temperature ionic conductivity exceeding [value missing] and a total ionic conductivity exceeding [value missing]. This invention is of great significance for the large-scale production of solid-state electrolytes and the promotion of their application in lithium metal batteries.

Description

Technical Field

[0001] This invention belongs to the field of all-solid-state lithium metal battery technology, and specifically relates to a method for preparing lithium-rich titanium phosphate lithium solid electrolyte and its application. Background Technology

[0002] As the global energy structure shifts towards cleaner and lower-carbon energy, the demand for high-performance energy storage technologies in fields such as electric vehicles, large-scale energy storage power stations, and portable electronic devices is becoming increasingly urgent. Traditional liquid lithium-ion batteries, due to their use of organic liquid electrolytes, pose safety hazards such as leakage, combustion, and explosion, and their energy density is already close to its theoretical limit, making it difficult to meet the application requirements of future high-end energy storage scenarios. Against this backdrop, solid-state lithium metal batteries, based on solid electrolytes and lithium metal anodes, are recognized by the domestic and international scientific and industrial communities as one of the most promising next-generation energy storage technologies, thanks to their advantages of eliminating the risk of liquid electrolyte leakage, suppressing lithium dendrite growth, and providing ultra-high energy density from the lithium metal anode. They have become a research hotspot in the field of new energy.

[0003] In the composition of solid-state lithium metal batteries, the solid electrolyte is the core component, undertaking the dual core functions of lithium-ion transport and separating the positive and negative electrodes to prevent short circuits. Its key indicators, such as ionic conductivity, chemical stability, electrochemical stability, mechanical properties, and cost, directly determine the energy density, cycle life, safety performance, and industrialization feasibility of solid-state lithium metal batteries. Therefore, developing high-performance, low-cost solid electrolytes is the core breakthrough for promoting the practical application of solid-state lithium metal batteries.

[0004] Currently, solid-state electrolytes developed globally can be mainly classified into four categories based on their chemical composition and structural characteristics: polymer solid-state electrolytes, oxide solid-state electrolytes, sulfide solid-state electrolytes, and halide solid-state electrolytes. Each type of electrolyte has its own advantages and disadvantages, and all have varying degrees of technical bottlenecks, making it difficult to fully meet the practical application requirements of solid-state lithium metal batteries.

[0005] Polymer solid electrolytes, represented by polyethylene oxide (PEO), possess good mechanical flexibility and processability, enabling them to form tight interfacial contacts with electrode materials, effectively reducing interfacial impedance. Furthermore, their fabrication processes are relatively simple and cost-effective. However, these electrolytes exhibit extremely low room-temperature ionic conductivity, typically below [value missing]. Even with optimization through methods such as combining with inorganic fillers and chemical modification, its room temperature ionic conductivity remains difficult to break through. This cannot meet the ion transport requirements of solid-state batteries during actual operation, which greatly limits their application in room temperature energy storage scenarios.

[0006] sulfide solid electrolytes (such as) , (etc.) and halide solid electrolytes (such as...) , (etc.) has become a research hotspot in recent years, with its outstanding advantage being its high room-temperature ionic conductivity, which can reach... At a level comparable to liquid electrolytes in ion transport performance, sulfide electrolytes also possess good plasticity and ductility, enhancing their contact characteristics with electrodes. However, both types of electrolytes suffer from severe chemical stability defects: sulfide electrolytes are highly susceptible to hydrolysis in humid environments, such as... It produces highly toxic substances upon contact with water. Gases not only cause electrolyte performance failure but also pose safety risks. Furthermore, they are easily oxidized in air, requiring operation under inert gas protection, significantly increasing preparation and application costs. Halogenated electrolytes are also prone to hydrolysis reactions, such as… Hydrolysis produces corrosive HCl gas, and its ionic conductivity decreases by about 60% when the relative humidity is greater than 30%. This makes it extremely difficult to dry when used in battery manufacturing and can also cause safety hazards such as poor battery cycle performance and gas swelling. Although its stability can be improved by surface coating, this will significantly increase the interfacial impedance and cannot meet the actual production requirements.

[0007] Oxide solid electrolytes have become the most promising candidate solid electrolyte system for practical application due to their outstanding advantages of high ionic conductivity, excellent chemical stability and electrochemical stability. They not only have good stability in air and humid environments, but also have good compatibility with lithium metal anodes and various cathode materials, which can effectively suppress the occurrence of interfacial side reactions and provide a guarantee for the long-term cycle stability of solid lithium metal batteries.

[0008] Based on differences in crystal structure, oxide solid electrolytes can be further classified into lithium superion conductor structures (…). Sodium superionic conductor structure ( ), Garnet structure ( ) and perovskite structure ( There are four main categories of oxide electrolytes, each with its own strengths and weaknesses: garnet-structured electrolytes (such as...) It exhibits excellent stability, but its preparation is difficult and costly; the ionic conductivity of perovskite structure electrolytes needs to be improved. Structural electrolytes have certain limitations in terms of compatibility. And... Oxide electrolytes with unique three-dimensional open framework structures provide a fast transport channel for lithium ions, and combine high ionic conductivity with structural stability, making them a key research area in oxide electrolytes.

[0009] exist Lithium-rich type in structural oxide electrolytes Solid electrolytes exhibit exceptionally high overall performance, making them promising candidate materials for industrialization: Firstly, these materials possess ultra-high bulk room-temperature ionic conductivity, reaching [value missing]. This is due to its high carrier concentration and three-dimensional continuous ion transport channels, which enable efficient and rapid migration of lithium ions, meeting the operational requirements of solid-state batteries; secondly, the material composition is stable for lithium metal. With a content exceeding 85%, it exhibits excellent stability to lithium metal; thirdly, the material is composed only of lithium (Li), titanium (Ti), phosphorus (P), and oxygen (O), all elements abundant in the Earth's crust, widely available and easily accessible, eliminating reliance on rare and precious metals and effectively reducing material preparation costs; fourthly, the material is non-toxic, non-corrosive, and causes no environmental pollution, aligning with the development trend of the green new energy industry and possessing the environmental foundation for large-scale industrial application. Based on these performance and cost advantages, Solid electrolytes have become one of the core candidate materials for promoting the practical application of solid lithium metal batteries, and have broad application prospects.

[0010] However, the industrialization process of this material is currently severely constrained by the preparation technology. To date, publicly reported... The preparation method of solid electrolytes was only developed in 1991. The research group and 1992 The high-temperature solid-state reaction method reported by the research group is a classic preparation process for traditional inorganic non-metallic materials. Its core principle is to mix raw materials such as lithium source, titanium source, and phosphorus source in a certain proportion and then calcine them under high temperature conditions for a long time to cause the raw materials to undergo a solid-state reaction to generate the target product.

[0011] This high-temperature solid-state reaction method suffers from numerous insurmountable drawbacks, severely limiting its large-scale application: First, the method requires continuous calcination at 900℃ for 5 days, consuming significant amounts of electrical and thermal energy, resulting in a lengthy preparation cycle and substantially increasing material preparation costs and production efficiency. Second, high-temperature calcination places extremely high demands on the preparation equipment, requiring specialized high-temperature and corrosion-resistant calcination equipment, leading to substantial investment and further raising the industrialization threshold. Third, during the solid-state reaction, ensuring uniform mixing of raw materials is difficult, easily resulting in incomplete local reactions and uneven product composition, causing significant fluctuations in the ionic conductivity, stability, and other properties of the finished product, affecting product quality consistency. Finally, in large-scale production, problems such as uneven raw material mixing and uneven distribution of high-temperature calcination temperature become even more pronounced, leading to a significant decrease in product qualification rate and failing to meet the needs of large-scale industrial production. Therefore, the existing high-temperature solid-state reaction method is no longer suitable. The need for large-scale preparation of solid electrolytes has made the development of novel, efficient, energy-saving, and scalable synthesis methods a pressing technical challenge.

[0012] In summary, Solid-state electrolytes, as core candidate materials for solid-state lithium metal batteries, possess outstanding advantages such as high ionic conductivity, excellent stability, low cost, and environmental friendliness. However, existing preparation methods suffer from serious drawbacks, including energy consumption, time-consuming processes, demanding equipment requirements, and inability to achieve large-scale production. These shortcomings represent a key technological gap hindering their practical application and the industrialization of solid-state lithium metal batteries. Therefore, developing simple, energy-efficient, and scalable synthesis methods is crucial. The new solid-state electrolyte technology can not only fill the technological gap in this field, but also promote... The industrial application of these materials can also accelerate the practical application of solid-state lithium metal batteries, provide technical support for the upgrading and development of the new energy storage industry, and have important academic research value and significant industrial application significance. Summary of the Invention

[0013] Based on the above reasons, and addressing the problems or deficiencies in existing technologies, the present invention aims to provide a method for synthesizing lithium-rich titanium phosphate lithium solid electrolyte, solving or at least partially solving the problems in existing preparation technologies: the present invention is based on the sol-gel method, uses readily available and low-cost raw materials, and achieves batch synthesis through a simple stirring process. Solid electrolyte. Furthermore, the synthesized sample exhibits nanoscale particle size, with an average particle size less than 450 nm and a narrow particle size distribution. Prepared via sol-gel method. Solid electrolytes exhibit extremely high bulk room temperature ionic conductivity ( Total ionic conductivity exceeds .

[0014] To achieve the first objective of this invention, the technical solution adopted by this invention is as follows:

[0015] The present invention discloses a method for preparing lithium-rich titanium phosphate lithium solid electrolyte, characterized in that the preparation method comprises the following steps:

[0016] (1) Weigh out the Li source, Ti source and P source. The molar ratio is The Ti source was dispersed in an organic solvent system and stirred until homogeneous;

[0017] (2) Add deionized water to the solution obtained in step (1) and stir continuously. Then add the Li source and P source in molar ratio and stir under heating until the precursor sol is obtained. The precursor sol is dried to form a precursor solid.

[0018] (3) The precursor solid is obtained by calcining it at high temperature. Solid electrolyte powder.

[0019] In step (1), the Li source and the P source are The Ti source is one or both of tetrabutyl titanate and propyl titanate; the organic solvent is one or both of anhydrous ethanol and isopropanol; the organic solvent and The mass ratio is .

[0020] Preferably, in step (1), the Ti source is tetrabutyl titanate; the organic solvent is anhydrous ethanol; the organic solvent and The mass ratio is 1.2:1.

[0021] Preferably, in step (1), the molar ratio of Li:Ti:P is 3:2:3.

[0022] In step (2), the deionized water and The mass ratio is 0.5~2:1; preferably 1:1; the temperature during heating and stirring is 100~150℃, preferably 120℃; the heating and stirring time is 6~8h.

[0023] In step (3), the high-temperature calcination temperature is 700~900℃. o C, preferably 800℃, with a heating rate of 5. o The temperature is C / min, and the holding time is 8~12h, preferably 8h.

[0024] In step (3), the calcination atmosphere consists of 5% (v / v) hydrogen and 95% (v / v) argon.

[0025] In step (3), the aforementioned It is an orthorhombic crystal system, space group Pbcn, with unit cell parameters of... , , , The aforementioned The key XRD data for the crystal are as follows: angles 2θ are 20.7°, 23.0°, and 24.4°.

[0026] In step (3), the prepared The solid electrolyte powder has a particle morphology, and the particle size distribution is D. 10 =333nm, D 50 =416nm, D 90 =516nm.

[0027] The present invention prepared Applications in solid-state lithium metal batteries Solid electrolyte sheets are solid electrolytes.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) This invention is for the preparation of high-temperature solid-state reaction method Solid electrolytes suffer from problems such as energy and time consumption, and uneven mixing of raw materials. Therefore, a sol-gel based method is proposed. A method for synthesizing solid electrolytes. This method only requires... Uniform mixing of raw materials can be achieved by stirring for 6-8 hours, and over 100g of precursor powder was prepared in a 500mL beaker. The precursor powder prepared by this method... The solid electrolyte powder consists of nanoparticles with a narrow particle size distribution and possesses properties exceeding [a certain limit]. Bulk room temperature ionic conductivity, super The total ionic conductivity. Furthermore, this method also features low raw material costs, simple process, and high repeatability, possessing potential practical value. This invention is suitable for large-scale production. Solid electrolytes are of great significance.

[0030] (2) The preparation method of the present invention is simple, energy-saving and suitable for large-scale production. The advantages of this method are that by optimizing the precursor preparation and reaction conditions, the synthesis temperature is significantly reduced and the reaction cycle is shortened. The resulting electrolyte material has a pure phase and excellent ionic conductivity, which effectively solves the key problem of practical preparation of this material and has important value for promoting the industrial application of high-safety and high-energy-density solid-state lithium metal batteries. Attached Figure Description

[0031] Figure 1 It is the calcined product obtained in Example 1 of this invention. X-ray diffraction pattern, AC impedance pattern, and activation energy diagrams based on bulk and total ionic conductivity of the powder, respectively;

[0032] a—X-ray diffraction pattern, b—AC impedance pattern, c—Activation energy diagram based on bulk ionic conductivity, d—Activation energy diagram based on total ionic conductivity.

[0033] Figure 2 This is the result of Embodiment 1 of the present invention. Optical photographs of the precursor and the calcined powder.

[0034] Figure 3 It is the calcined product obtained in Example 1 of this invention. Scanning electron microscope image and particle size distribution map of the powder;

[0035] a—Scanning electron microscope image, b—Particle size distribution map.

[0036] Figure 4It is the calcined product obtained in Example 2 of this invention. X-ray diffraction pattern and AC impedance spectrum of the powder;

[0037] a—X-ray diffraction pattern, b—AC impedance pattern.

[0038] Figure 5 The calcined product obtained in Example 3 of this invention X-ray diffraction pattern and AC impedance spectrum of the powder;

[0039] a—X-ray diffraction pattern, b—AC impedance pattern.

[0040] Figure 6 It is the calcined product obtained in Example 4 of this invention. X-ray diffraction pattern and AC impedance spectrum of the powder;

[0041] a—X-ray diffraction pattern, b—AC impedance pattern.

[0042] Figure 7 It is the calcined product obtained in Example 5 of this invention. X-ray diffraction pattern and AC impedance spectrum of the powder;

[0043] a—X-ray diffraction pattern, b—AC impedance pattern. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0045] The method for calculating the ionic conductivity (σ) involved in the following embodiments of the present invention is as follows:

[0046] (Formula 1);

[0047] The parameters are defined as follows: L represents the thickness of the electrolyte sheet (cm), which needs to be measured at multiple points using a micrometer and the average value taken; S represents the effective area of ​​the electrolyte sheet (cm). R represents the resistance obtained from the fitting ( ).

[0048] The activation energy involved in the following embodiments of the present invention ( ) is calculated using the Arrhenius formula:

[0049] (Formula 2);

[0050] The parameters are defined as follows: A is the exponential factor, and T is the absolute temperature (K). It is the Boltzmann constant.

[0051] Example 1

[0052] This embodiment Solid electrolytes are prepared by sol-gel method to prepare precursor powder followed by high-temperature calcination. The specific preparation method is as follows:

[0053] (1) Add 112.25g of anhydrous ethanol and 204.2g of tetrabutyl titanate to a 500mL beaker and stir well. After adding 93.54g of deionized water, add 93.54g of lithium dihydrogen phosphate (i.e., the molar ratio of Li:Ti:P = 3:2:3).

[0054] (2) Heating and stirring at 120℃ ensures uniform mixing of the raw materials and simultaneous solvent evaporation. The stirring speed is 1000 rpm. At this temperature, a good balance can be achieved between the raw material mixing rate and the solvent evaporation rate, avoiding uneven mixing due to excessively high temperature and rapid evaporation, or excessively low temperature and long evaporation time, resulting in low production efficiency. After heating and stirring for about 6 hours, a uniform precursor sol can be formed. The precursor sol is then placed in an 80℃ forced-air drying oven to dry and form a precursor solid.

[0055] (3) The precursor solid was placed in a tube furnace and calcined at a rate of 5°C / min to 800°C and held for 8 hours. Then it was allowed to cool naturally to room temperature. The calcination atmosphere consisted of 5% (v / v) hydrogen and 95% (v / v) argon.

[0056] (4) The calcined sample was wet-milled using a high-energy ball mill to obtain the final product. Solid electrolyte powder, ball-to-powder ratio of 5:1, isopropanol:raw material = 1.5:1, ball milling speed of 1200 rpm, ball milling time of 120 min, working mode of 30 min ball milling, 15 min rest.

[0057] The product prepared in Example 1 was subjected to phase analysis and AC impedance testing. Figure 1 It is the result of Example 1 X-ray diffraction pattern, AC impedance spectroscopy, and activation energy diagram of the powder. Figure 1 As can be seen from a, the positions of the diffraction peaks of the synthesized material are related to... The standard spectrum matches, meaning the synthesized material is However, for Example 1 and A comparison of the unit cell parameters of the standard cards revealed that the unit cell of Example 1 is smaller, as shown in Table 1. The smaller unit cell allows for better control of Li... + The initial state energy is higher, resulting in a lower migration energy barrier and faster ion migration. Therefore, the sol-gel method can be used to prepare... Solid electrolytes have potentially high bulk ionic conductivity. Figure 1 bd represents the AC impedance spectrum and activation energy diagram of Example 1. The specific testing process is as follows: The AC impedance spectrum and activation energy diagram of Example 1 are... The powder was compressed into tablets at 800 MPa and sintered at 800 °C in 5% (v / v) hydrogen and 95% (v / v) argon for 10 h. Electrolyte sheet; the electrolyte sheet is polished successively with 320-grit, 1000-grit, 2000-grit, and 8000-grit sandpaper, and then coated with conductive silver paste. A blocking battery was then used, and AC impedance measurements were performed at different temperatures using an Autolab electrochemical workstation. The test frequency was [missing information]. The amplitude is 50mV. The bulk ionic conductivity and total ionic conductivity of the solid electrolyte are calculated according to equation (I), where: , ,Depend on Figure 1 b indicates that , , The bulk room temperature ionic conductivity of solid electrolytes is The total ionic conductivity is .Depend on Figure 1 c indicates that the activation energy based on bulk ionic conductivity in Example 1 is... The activation energy based on total ionic conductivity is The above data indicate that the sol-gel method prepares... Solid electrolytes have high ionic conductivity and are highly commercially promising.

[0058]

[0059] Figure 2 These are optical photographs of the precursor powder (left) and the calcined powder (right) from Example 1, demonstrating the effectiveness of the sol-gel method in large-scale preparation. The potential of solid electrolytes.

[0060] Figure 3 a is a scanning electron microscope image of Example 1, which shows that its microstructure consists of nanoscale particles. The large particles in the image may be secondary particles formed by the aggregation of primary nanoscale particles. Figure 3 b is the particle size distribution diagram of Example 1, which , , Furthermore, the figure shows that its particle size distribution is relatively narrow. The smaller particle size and narrower particle size distribution result in… The powder exhibits higher density during pre-pressing and sintering into ceramic sheets, resulting in lower grain boundary resistance. Therefore, compared to materials prepared by other methods... Powder, prepared by sol-gel method Powder sintering Electrolyte sheets have a higher total ionic conductivity.

[0061] Example 2

[0062] This embodiment The solid electrolyte powder was prepared by calcining a precursor using the sol-gel method. The preparation steps were basically the same as in Example 1. The only difference between Example 2 and Example 1 was that... molar ratio = The final X-ray diffraction pattern and AC impedance spectrum of the powder are as follows: Figure 4 As shown. By Figure 4 As can be seen from this, compared to Example 1, Example 2 exhibits additional diffraction peaks, indicating the presence of impurities in Example 2. Analysis revealed that the impurities are... The possible reason is The concentration was low, resulting in a low Li content. .Depend on Figure 4 As can be seen from b, the ionic conductivity of Example 2 is lower than that of Example 1, which is due to impurities. The existence of.

[0063] Example 3

[0064] This embodiment The solid electrolyte powder was prepared by calcining a precursor using the sol-gel method. The preparation steps were basically the same as in Example 1. The only difference between Example 3 and Example 1 was that... molar ratio = The final X-ray diffraction pattern and AC impedance spectrum of the powder are as follows: Figure 5 As shown. By Figure 5 As can be seen from this, compared to Example 1, the diffraction peak intensity of Example 3 is lower, indicating that the crystallinity of Example 3 is not as good as that of Example 1. This may be due to the presence of impurities in the precursor powder. High concentrations can lead to intergranular deformation during calcination. Strong interactions make long-range ordering difficult to maintain, ultimately leading to low crystallinity. Figure 5 b shows that the ionic conductivity of Example 3 is lower than that of Example 1, which is due to the lower crystallinity.

[0065] Example 4

[0066] This embodiment The solid electrolyte powder was prepared by calcining a precursor using the sol-gel method. The preparation steps were basically the same as in Example 1. The only difference between Example 4 and Example 1 was that... molar ratio = The final X-ray diffraction pattern and AC impedance spectrum of the powder are as follows: Figure 6 As shown. By Figure 6 As can be seen from a, compared to Example 1, Example 4 exhibits additional diffraction peaks, indicating the presence of impurities in Example 4. Analysis shows that the impurities are... The possible reason is that there are far more Li and P sources than The molar ratio of the stoichiometric ratio led to The generation of . (By ) Figure 6 As can be seen from b, the ionic conductivity of Example 4 is lower than that of Example 1, which is due to impurities. The existence of.

[0067] Example 5

[0068] This embodiment The solid electrolyte powder was prepared by calcination after preparing a precursor using the sol-gel method. The preparation steps were basically the same as in Example 1. The only difference between Example 5 and Example 1 was that the Ti source was propyl titanate, the solvent was isopropanol, and the stirring time was approximately 8 hours. The extended stirring time was due to the higher boiling point of isopropanol compared to anhydrous ethanol, thus requiring a longer stirring time when preparing the precursor sol. The X-ray diffraction pattern and AC impedance spectroscopy of the final powder are shown below. Figure 7 As shown. By Figure 7 As can be seen from this, compared to Example 1, Example 5 exhibits additional diffraction peaks, indicating the presence of impurities in Example 5. Analysis further indicates that the impurities are... The possible reason for the formation of impurities is that propyl titanate hydrolyzes more rapidly than tetrabutyl titanate, inevitably leading to the formation of some Ti impurities during hydrolysis. After calcination, it was obtained . Figure 7 As can be seen from b, the ionic conductivity of Example 5 is lower than that of Example 1, which is due to impurities. The existence of.

[0069] As can be seen from Examples 1-4, molar ratio = All can be generated But only when molar ratio = When obtained The highest ionic conductivity was observed, which may be due to the preparation of other molar ratios. Solid electrolytes contain impurities ( or The low crystallinity or poor crystalline quality affected the ionic conductivity. As can be seen from Examples 1 and 5, tetrabutyl titanate or propyl titanate can be used as the titanium source, and anhydrous ethanol or isopropanol can be used as the solvent to prepare the product. A solid electrolyte is used, but the preferred titanium source is tetrabutyl titanate, and the solvent is anhydrous ethanol. This is because the hydrolysis reaction of tetrabutyl titanate is milder than that of propyl titanate and is less likely to generate impurities; anhydrous ethanol has a lower boiling point than isopropanol, requiring less heating and stirring time, which is beneficial to improving production efficiency.

[0070] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a lithium-rich lithium titanium phosphate solid electrolyte, characterized in that: The preparation method comprises the following steps: (1) Weigh out the Li source, Ti source and P source, with a molar ratio of Li:Ti:P of 2.8~3.4:2:2.8~3.4, disperse the Ti source in the organic solvent system and stir evenly; (2) Add deionized water to the solution obtained in step (1) and stir continuously. Then add the Li source and P source in molar ratio and stir under heating until the precursor sol is obtained. The precursor sol is dried to form a precursor solid. (3) The precursor solid is obtained by calcining it at high temperature. Solid electrolyte powder.

2. The preparation method according to claim 1, characterized in that: In step (1), the Li source and the P source are The Ti source is one or both of tetrabutyl titanate and propyl titanate; the organic solvent is one or both of anhydrous ethanol and isopropanol; the organic solvent and The mass ratio is 1~2:

1.

3. The preparation method according to claim 2, characterized in that: In step (1), the Ti source is tetrabutyl titanate; the organic solvent is anhydrous ethanol; the organic solvent and The mass ratio is 1.2:

1.

4. The preparation method according to claim 1, characterized in that: In step (1), the molar ratio of Li:Ti:P is 3:2:

3.

5. The preparation method according to claim 1, characterized in that: In step (2), the deionized water and The mass ratio is 0.5~2:1; the temperature during heating and stirring is 100~150℃; and the heating and stirring time is 6~8h.

6. The preparation method according to claim 1, characterized in that: In step (3), the high-temperature calcination temperature is 700~900℃. o C, heating rate is 5 o The temperature is C / min, and the holding time is 8~12h.

7. The preparation method according to claim 1, characterized in that: In step (3), the calcination atmosphere consists of 5% (v / v) hydrogen and 95% (v / v) argon.

8. The preparation method according to claim 1, characterized in that: In step (3), the aforementioned It is an orthorhombic crystal system, space group Pbcn, with unit cell parameters of... , , , The aforementioned The key XRD data for the crystal are as follows: angles 2θ are 20.7°, 23.0°, and 24.4°.

9. The preparation method according to claim 1, characterized in that: In step (3), the prepared The solid electrolyte powder has a particle morphology at the microscopic level, and the particle size distribution is as follows: , , .

10. The application of the lithium-rich titanium phosphate lithium solid electrolyte prepared by the method according to any one of claims 1-9 in solid lithium metal batteries.

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