Latp solid-state electrolyte, preparation method and application thereof, and solid-state battery

Abstract

The application provides a LATP solid electrolyte, a preparation method and application thereof, and a solid-state battery. The preparation method of the LATP solid electrolyte is characterized by using new soluble salts, titanyl sulfate, aluminum hydroxide, lithium acetate and ammonium dihydrogen phosphate, which are completely dispersed in water, and then introduced into a spray dryer through the high dispersibility of the aqueous solution, and continuously dehydrated and precipitated in the spray drying process to obtain a mixed precursor, and then sintered at high temperature to obtain the LATP electrolyte. The application can realize the rapid synthesis of the LATP solid electrolyte, greatly reduce the sanding time of the precursor, and reduce the production cost.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery technology, and in particular to an LATP solid electrolyte, its preparation method and application, and solid-state batteries. Background Technology

[0002] Traditional lithium-ion batteries use liquid electrolytes, which pose a series of safety hazards, including easy leakage, poor thermal stability, and the risk of fire and explosion due to internal short circuits. Solid-state electrolytes, compared to traditional liquid electrolytes, offer advantages such as high safety, high energy density, good cycle performance, wide operating temperature range, and convenient recycling. Solid-state electrolyte lithium-ion batteries are currently a research hotspot in the energy storage field. As a core component of solid-state rechargeable batteries, solid-state electrolytes have become a focus of research in this field in recent years. Among them, lithium aluminum phosphate titanium (LATP) exhibits stable physical properties, good processing resistance, and excellent high ionic conductivity, while avoiding the use of precious metals, thus making it more cost-competitive. Considering factors such as thermal safety characteristics, cost, and process maturity, it is a better technical route choice for solid-state batteries.

[0003] The current mainstream LATP solid electrolyte has the chemical formula Li 1.3 Al 0.3 Ti 1.7 (PO4)3, this material is low in cost, especially since it does not contain rare and expensive metals. Although LATP electrolyte has stable physical properties, its low lithium-ion conductivity is mainly due to the large particle size; commonly synthesized methods result in larger particle sizes and lower ion diffusion coefficients. Solid electrolyte Li 1.3 Al 0.3 Ti 1.7 The ionic conductivity of (PO4)3 is 1×10⁻⁶. -4 With a conductivity of around S / cm, LATP still suffers from low conductivity as a solid electrolyte. Current methods for preparing LATP solid electrolytes mainly include long-term sand milling and mixing of solid materials followed by high-temperature sintering. Another method is sol-gel or co-precipitation, but these methods have high raw material costs and low cost-effectiveness. Solid material synthesis has significant application potential, but solid mixing, especially the co-mixing and sintering of four solid phases, presents many challenges in crystal form control, particle size growth, and impurity phase formation. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a LATP solid electrolyte, its preparation method and application, and solid-state batteries. Addressing the efficiency and cost-effectiveness issues of traditional solid-phase methods and sol-gel or co-precipitation methods, this invention employs a novel soluble salt, first completely dispersed in an aqueous solution, then stably introduced into a spray dryer for rapid dehydration, leveraging the high dispersibility of the aqueous solution, to obtain a mixed salt precursor compound. This compound is then sintered at high temperature to obtain the LATP electrolyte.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a method for preparing LATP solid electrolyte, comprising the following steps:

[0007] Titanium sulfate, aluminum hydroxide, lithium acetate, and ammonium dihydrogen phosphate are added to water to obtain a mixed aqueous solution.

[0008] The mixed aqueous solution was spray-dried to obtain the precursor;

[0009] The precursor was calcined to obtain LATP solid electrolyte.

[0010] Preferably, sulfuric acid is added to water along with titanium oxysulfate, aluminum hydroxide, lithium acetate, and ammonium dihydrogen phosphate to obtain a mixed aqueous solution.

[0011] Preferably, the mass concentration of sulfuric acid in the mixed aqueous solution is 0.3-1%.

[0012] Preferably, in the step of spray drying the mixed aqueous solution, the spray drying temperature is 150~170℃.

[0013] Preferably, in the step of calcining the precursor, the calcination temperature is 850~900℃ and the calcination time is 6~7h.

[0014] Preferably, the precursor is heated from room temperature to 850-900°C at a rate of 5-6°C / min and calcined for 6-7 hours.

[0015] Preferably, the molar ratio of lithium in lithium acetate, titanium in titanium oxysulfate, aluminum in aluminum hydroxide, and phosphorus in ammonium dihydrogen phosphate is 1.3:1.7:0.3:3.

[0016] Secondly, the present invention also provides an LATP solid electrolyte, which is prepared by the preparation method described above.

[0017] Thirdly, the present invention also provides an LATP solid electrolyte prepared by the preparation method described above, or the application of the LATP solid electrolyte in the preparation of solid-state batteries.

[0018] Fourthly, the present invention also provides a solid-state battery, comprising the LATP solid electrolyte prepared by the aforementioned preparation method or the LATP solid electrolyte described above.

[0019] The LATP solid electrolyte, its preparation method, its application, and solid-state batteries of the present invention have the following advantages over the prior art:

[0020] The method for preparing LATP solid electrolyte of the present invention uses novel soluble salts, titanium oxysulfate, aluminum hydroxide, lithium acetate, and ammonium dihydrogen phosphate, which are first completely dispersed in water. Then, taking advantage of the high dispersibility of the aqueous solution, the mixture is stably introduced into a spray dryer. During the spray drying process, continuous dehydration precipitates a uniformly mixed precursor, which is then sintered at high temperature to obtain the LATP electrolyte. This invention enables a rapid synthesis method for LATP solid electrolyte, significantly reducing the milling time of the precursor and lowering production costs. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the preparation method of the LATP solid electrolyte of the present invention.

[0023] Figure 2 The XRD pattern of the lithium aluminum titanium phosphate solid electrolyte prepared in Example 1;

[0024] Figure 3 The image shows the XRD pattern of the lithium aluminum titanium phosphate solid electrolyte prepared in Comparative Example 1. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of embodiments. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single digits within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any referenced number (fraction or integer) within the indicated range.

[0027] This application provides a method for preparing LATP solid electrolyte, comprising the following steps:

[0028] S1. Add titanium sulfate, aluminum hydroxide, lithium acetate, and ammonium dihydrogen phosphate to water to obtain a mixed aqueous solution;

[0029] S2. Spray dry the mixed aqueous solution to obtain the precursor;

[0030] S3. The precursor is calcined to obtain LATP solid electrolyte.

[0031] The preparation method of LATP solid electrolyte of the present invention uses novel soluble salts, titanium oxysulfate, aluminum hydroxide, lithium acetate, and ammonium dihydrogen phosphate, which are first completely dispersed in water. Then, taking advantage of the high dispersibility of the aqueous solution, the mixture is stably introduced into a spray dryer. During the spray drying process, a uniformly mixed precursor is continuously dehydrated and precipitated. Finally, the precursor is sintered at high temperature to obtain the LATP electrolyte. In this invention, the raw materials are dissolved in an aqueous solution and continuously fed into a spray dryer. High-temperature rotating airflow rapidly achieves dehydration and precipitation, and the raw materials quickly achieve solid-phase mixing. In contrast, the traditional solid-phase method involves mixing the raw materials into powder and then adding them to a ball mill for high-speed ball milling, requiring continuous ball milling for more than 12 hours to ensure thorough bulk mixing of the solid powder. Compared to the traditional solid-phase method, the spray drying of the present invention achieves raw material mixing much faster (only 1 / 10 to 1 / 40 of the time required by the traditional method). This invention enables a rapid synthesis method for LATP solid electrolyte, significantly reducing the milling time of the precursor and reducing production costs.

[0032] In some embodiments, sulfuric acid is added to water along with titanium oxysulfate, aluminum hydroxide, lithium acetate, and ammonium dihydrogen phosphate to obtain a mixed aqueous solution.

[0033] In some embodiments, the mass concentration of sulfuric acid in the mixed aqueous solution is 0.3-1%.

[0034] In some embodiments, the sum of the mass fractions of titanium oxysulfate, aluminum hydroxide, lithium acetate, and ammonium dihydrogen phosphate in the mixed aqueous solution is 10-30%.

[0035] In some embodiments, during the spray drying step of the mixed aqueous solution, the spray drying temperature is 150~170°C. During spray drying, the water in the mixed aqueous solution gradually evaporates and is removed at high temperature, resulting in a mixed powder material of four substances, which is the precursor; specifically, during spray drying, the feed rate is 100~150 mL / min.

[0036] In some embodiments, in the step of calcining the precursor, the calcination temperature is 850~900℃ and the calcination time is 6~7h.

[0037] In some embodiments, the precursor is heated from room temperature (20-25°C) to 850-900°C at a rate of 5-6°C / min and calcined for 6-7 hours.

[0038] In some embodiments, the molar ratio of lithium in lithium acetate, titanium in titanium oxysulfate, aluminum in aluminum hydroxide, and phosphorus in ammonium dihydrogen phosphate is 1.3:1.7:0.3:3.

[0039] Further reference Figure 1 As shown, it is a schematic diagram of the preparation method of LATP solid electrolyte of the present invention. Specifically, four raw materials, namely titanium oxysulfate, aluminum hydroxide, lithium acetate and ammonium dihydrogen phosphate, are prepared into a mixed aqueous solution; the mixed aqueous solution is subjected to rapid dehydration treatment to obtain the intermediate product precursor for preparing LATP; the precursor is placed in a high-temperature furnace for calcination and other treatments to finally obtain the target product LATP.

[0040] Based on the same inventive concept, the present invention also provides an LATP solid electrolyte, which is prepared by the preparation method described above.

[0041] Based on the same inventive concept, the present invention also provides an LATP solid electrolyte prepared by the above-described preparation method or the application of the above-described LATP solid electrolyte in the preparation of solid-state batteries.

[0042] Based on the same inventive concept, the present invention also provides a solid-state battery, comprising the LATP solid electrolyte prepared by the above-described preparation method or the LATP solid electrolyte described above.

[0043] The following further illustrates the lithium aluminum titanium phosphate solid electrolyte, its preparation method, applications, and solid-state batteries of this application with specific embodiments. This section further illustrates the content of the present invention with reference to specific embodiments, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the art.

[0044] Example 1

[0045] This embodiment provides a method for preparing LATP solid electrolyte, including the following steps:

[0046] S1. Weigh lithium acetate, titanium oxysulfate, aluminum hydroxide, and ammonium dihydrogen phosphate according to the molar ratio of lithium, titanium, aluminum, and phosphorus of 1.3:1.7:0.3:3.

[0047] Lithium acetate, titanium oxysulfate, aluminum hydroxide, ammonium dihydrogen phosphate, and sulfuric acid were added to water to obtain a mixed aqueous solution; the mass concentration of sulfuric acid in the mixed aqueous solution was 0.5%; the sum of the mass fractions of lithium acetate, titanium oxysulfate, aluminum hydroxide, and ammonium dihydrogen phosphate in the mixed aqueous solution was 30%.

[0048] S2. Spray dry the mixed aqueous solution (feed rate of 100 mL / min) to evaporate and remove water (total time less than 1 h) to obtain the precursor; the spray drying temperature is 160 °C.

[0049] S3. The precursor was heated from room temperature (25°C) to 850°C at a rate of 5°C / min and calcined for 6 hours to obtain LATP solid electrolyte.

[0050] Comparative Example 1

[0051] This comparative example provides a method for preparing LATP solid electrolyte using conventional solid-phase synthesis, including the following steps:

[0052] S1. Titanium dioxide, aluminum oxide, lithium carbonate, and ammonium dihydrogen phosphate powders are placed in a ball mill at 100 r / min for 20 h according to the molar ratio of Ti:Al:Li:P of 1.7:0.3:1.3:3, and then the mixture is taken out to obtain a mixed powder.

[0053] S2. The above mixed powder is heated from room temperature to 850°C at a rate of 8°C / min and held for 5 hours to obtain LATP solid electrolyte (Li). 1.3 Ti 1.7 Al 0.3 (PO4)3).

[0054] Figure 2 The XRD pattern of the LATP solid electrolyte prepared in Example 1;

[0055] Figure 3 The image shows the XRD pattern of the LATP solid electrolyte prepared in Comparative Example 1.

[0056] from Figure 2 As can be seen from the data, the material synthesized in Example 1 possesses the characteristic peaks of LATP solid electrolyte.

[0057] from Figure 3 It can be seen that the XRD curve of the LATP solid electrolyte prepared in Comparative Example 1 has a lot of impurity peaks and background noise. Although the main component is lithium titanium aluminum phosphate material, there are many generated impurities and noise peaks caused by large differences in particle size.

[0058] It is understood that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0059] The above are merely preferred embodiments of this application, and only specifically describe the technical principles of this application. These descriptions are only for explaining the principles of this application and should not be construed as limiting the scope of protection of this application in any way. Based on this explanation, any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application, as well as other specific embodiments of this application that can be conceived by those skilled in the art without creative effort, should be included within the scope of protection of this application.

Claims

1. A method for preparing LATP solid electrolyte, characterized in that, Includes the following steps: Titanium sulfate, aluminum hydroxide, lithium acetate, and ammonium dihydrogen phosphate are added to water to obtain a mixed aqueous solution. The mixed aqueous solution was spray-dried to obtain the precursor; The precursor was calcined to obtain LATP solid electrolyte; When titanium oxysulfate, aluminum hydroxide, lithium acetate, and ammonium dihydrogen phosphate are added to water, sulfuric acid is also added to obtain a mixed aqueous solution. The mass concentration of sulfuric acid in the mixed aqueous solution is 0.3% to 1%. In the step of spray drying the mixed aqueous solution, the spray drying temperature is 150~170℃, and the feed rate is 100~150mL / min. In the step of calcining the precursor, the calcination temperature is 850~900℃ and the calcination time is 6~7h; The molar ratio of lithium in lithium acetate, titanium in titanium oxysulfate, aluminum in aluminum hydroxide, and phosphorus in ammonium dihydrogen phosphate is 1.3:1.7:0.3:

3.

2. The method for preparing LATP solid electrolyte as described in claim 1, characterized in that, The precursor is heated from room temperature to 850-900℃ at a rate of 5-6℃ / min and calcined for 6-7 hours.

3. An LATP solid electrolyte, characterized in that, It is prepared by any one of the preparation methods described in claims 1 to 2.

4. The application of an LATP solid electrolyte prepared by any one of the preparation methods described in claims 1 to 2 or the LATP solid electrolyte described in claim 3 in the preparation of solid-state batteries.

5. A solid-state battery, characterized in that, Includes LATP solid electrolyte prepared by any of the preparation methods described in claims 1 to 2 or LATP solid electrolyte as described in claim 3.

Images