Modified lithium aluminum titanium phosphate, preparation method therefor, and lithium-ion solid-state battery

Abstract

Modified lithium aluminum titanium phosphate (LATP), a preparation method therefor, and a lithium-ion solid-state battery. The modified LATP comprises a LATP matrix and a coating layer, wherein the LATP matrix is represented by Li1.3Al0.3Ti1.7(PO4)3, and the coating layer is formed by ZrxSi1-xO2 / TiO2, wherein x is 0.1 to 0.9, and the particle size of ZrxSi1-xO2 / TiO2 is less than the particle size of Li1.3Al0.3Ti1.7(PO4)3. The modified LATP material having the composition has advantages such as high ionic conductivity, high capacity retention rate, and good thermal stability.

Description

Modified lithium aluminum titanium phosphate, preparation method thereof and lithium ion solid-state battery

[0001] This application is based on the Chinese application with CN application number 202311447909.7 and application date November 2, 2023, and claims its priority. The disclosed content of the CN application is again introduced as a whole into this application. Technical Field

[0002] The present application relates to the field of solid electrolytes, and more specifically, to a modified lithium aluminum titanium phosphate, a preparation method thereof, and a lithium-ion solid-state battery. Background Art

[0003] Traditional lithium-ion batteries suffer from poor cycling performance and potential safety issues. The development of all-solid-state lithium-ion batteries can address these issues. Compared to traditional commercial lithium-ion batteries, all-solid-state batteries offer advantages such as improved cycling performance and safety, superior material stability, a wider operating range, higher power and energy density, a lithium-ion conductor that is less susceptible to chemical hardening, and simple and convenient operation. Due to their high energy density and excellent safety performance, all-solid-state batteries are expected to be widely used in large-scale power storage systems such as electric vehicles and electronic devices.

[0004] One of the core elements of all-solid-state lithium-ion batteries is the solid electrolyte material. Among the solid electrolyte materials, NASICON-type materials LM2(PO4)3 (L=Li, Na, K; M=Ge, Ti, Sn, Hf, Zr) have been widely studied due to their high ionic conductivity. 1+x Al x Ti 2-x (PO4)3, LATP) has received more and more attention. At present, the most commonly used methods for preparing LATP solid electrolytes are sol-gel method, molten salt quenching method, water cooling method and high-temperature solid phase method. Existing literature reports that Al2O3 is used as the aluminum source in the solid phase method, and aluminum nitrate is generally used as the aluminum source in the sol-gel or hydrothermal method and solution-related preparation. The ionic conductivity of the ceramic body sintered by the LATP powder prepared by the sol-gel method can reach 10 -4 S / cm. The ionic conductivity of nano-LATP obtained by high-energy ball milling solid phase method is also 10 -4 S / cm.

[0005] The existing LATP materials rely on the migration of conductive particles, and the tightness of the crystal arrangement inside the lithium ion conductor has an important influence on the migration rate of ions inside the conductor. The main problems of the existing LATP materials are the low ionic conductivity and the presence of Ti 4+ With Ti 3+The actual capacity loss will affect the performance of the LATP material. Therefore, it is necessary to provide a LATP material with high ionic conductivity and high capacity retention rate.

[0006] Summary of the Invention

[0007] The main purpose of this application is to provide a modified lithium aluminum titanium phosphate, a preparation method thereof and a lithium ion solid-state battery to solve the problems of low ionic conductivity and low capacity retention rate of existing LATP materials.

[0008] In order to achieve the above-mentioned object, the present application provides a modified lithium aluminum titanium phosphate, comprising a lithium aluminum titanium phosphate matrix and a coating layer, wherein the lithium aluminum titanium phosphate matrix is ​​Li 1.3 Al 0.3 Ti 1.7 (PO4)3, the coating layer is composed of Zr x Si 1-x O2 / TiO2 is formed, where x is 0.1 to 0.9, Zr x Si 1-x The particle size of O2 / TiO2 is smaller than that of Li 1.3 Al 0.3 Ti 1.7 Particle size of (PO4)3.

[0009] Furthermore, the particle size D50 of the modified lithium aluminum titanium phosphate is 0.9-1.5 μm, and Dmax is less than 10 μm.

[0010] Furthermore, the amount ratio of the lithium aluminum titanium phosphate matrix to the coating layer is 1:(0.001-0.02).

[0011] The second aspect of the present application also provides a method for preparing the modified lithium titanium aluminum phosphate, comprising: preparing a lithium titanium aluminum phosphate matrix; mixing the lithium titanium aluminum phosphate matrix with Zr x Si 1-x O2 / TiO2 is physically coated to obtain modified lithium titanium aluminum phosphate.

[0012] Furthermore, preparing a lithium titanium aluminum phosphate matrix includes: dry mixing, sintering and first grinding a mixture of a lithium source compound, an aluminum source compound, a titanium source compound and a phosphorus source compound in sequence to obtain a lithium titanium aluminum phosphate matrix; preferably, the molar ratio of the Li element in the lithium source compound, the Al element in the aluminum source compound, the Ti element in the titanium source compound and the P element in the phosphorus source compound is (1.3~1.35):0.3:1.7:3.

[0013] Furthermore, the dry mixing process includes: mixing the mixture of the lithium source compound, the aluminum source compound, the titanium source compound and the phosphorus source compound at a rotation speed of 200-400 rpm for 3-5 minutes, and then mixing at a rotation speed of 700-900 rpm for 3-5 minutes.

[0014] Furthermore, the sintering process is carried out in an air atmosphere, and the sintering temperature is 800-950° C., and the constant temperature time is 6-15 hours.

[0015] Furthermore, the first grinding includes ultrafine grinding the sintered product using deionized water as a solvent to a particle size D50 of 0.5 to 0.6 μm.

[0016] Furthermore, the physical coating includes: the lithium aluminum titanium phosphate matrix and the Zr x Si 1-x The O2 / TiO2 mixture is sequentially subjected to a second grinding, spray drying and pulverization to obtain modified lithium aluminum titanium phosphate; preferably, after the second grinding, the particle size D50 of the mixture is 0.2-0.3 μm; preferably, the spray drying conditions are an inlet air temperature of 220-250°C and an outlet air temperature of 90-110°C; preferably, the pulverization is air flow pulverization, and after pulverization, the particle size D50 of the particulate matter is 0.9-1.5 μm, and Dmax is less than 10 μm.

[0017] The third aspect of the present application further provides a lithium-ion solid-state battery, comprising a solid-state electrolyte, wherein the solid-state electrolyte is the above-mentioned modified lithium aluminum titanium phosphate or is prepared by the above-mentioned preparation method.

[0018] Applying the technical solution of this application, Zr x Si 1-x The coating layer formed by O2 / TiO2 on the surface of LATP material can effectively increase the ionic conductivity of LATP material. Its application in ternary cathode material can effectively increase the differential scanning calorimetry peak temperature, improve the capacity and thermal stability of ternary material. x Si 1-x The particle size of O2 / TiO2 is smaller than that of Li 1.3 Al 0.3 Ti 1.7 The particle size of (PO4)3 can make Zr x Si 1-x O2 / TiO2 is better coated on the surface of the LATP material, thereby reducing the voids and gaps on the surface of the LATP material, thereby improving its ionic conductivity. On this basis, the modified LATP material with the above composition has the advantages of high ionic conductivity and capacity retention rate, as well as good thermal stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings that constitute part of this application are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation on this application. In the drawings:

[0020] FIG1 is an XRD pattern of the modified LATP material prepared in Example 3 of the present application and the LATP material prepared in Comparative Example 1;

[0021] FIG2 is a SEM image of the modified LATP material prepared in Example 3 of the present application;

[0022] FIG3 is a SEM image of the LATP material prepared in Comparative Example 4 of the present application. DETAILED DESCRIPTION

[0023] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the embodiments.

[0024] As described in the background technology, the existing LATP materials have the problems of low ion conductivity and low capacity retention. In order to solve the above technical problems, the present application provides a modified lithium aluminum titanium phosphate, which includes a lithium aluminum titanium phosphate matrix and a coating layer, wherein the lithium aluminum titanium phosphate matrix is ​​Li 1.3 Al 0.3 Ti 1.7 (PO4)3, the coating layer is composed of Zr x Si 1-x O2 / TiO2 is formed, where x is 0.1 to 0.9, Zr x Si 1-x The particle size of O2 / TiO2 is smaller than that of Li 1.3 Al 0.3 Ti 1.7 Particle size of (PO4)3.

[0025] Zr x Si 1-x The coating layer formed by O2 / TiO2 on the surface of LATP material can effectively increase the ionic conductivity of LATP material. Its application in ternary cathode material can effectively increase the differential scanning calorimetry peak temperature, improve the capacity and thermal stability of ternary material. x Si 1-x The particle size of O2 / TiO2 is smaller than that of Li 1.3 Al 0.3 Ti 1.7 The particle size of (PO4)3 can make Zr x Si 1-xO2 / TiO2 is better coated on the surface of the LATP material, thereby reducing the voids and gaps on the surface of the modified lithium aluminum titanium phosphate material, thereby improving its ionic conductivity. On this basis, the modified LATP material with the above composition has the advantages of high ionic conductivity and capacity retention rate, as well as good thermal stability.

[0026] It should be noted that the Zr x Si 1-x In O2 / TiO2, x can be selected from 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or a range formed by any two of the above values. It can be a commercial product or a homemade method. The preferred preparation method is: first, TiO2 nanotubes are coated with oleic acid, hydrolyzed with hexaalkyltrimethylammonium bromide, ethyl orthosilicate and zirconium oxychloride octahydrate, calcined with the oleic acid layer, and then silanized and phosphorylated to prepare phosphoric acid-promoted Zr x Si 1-x O2 / TiO2 composite materials.

[0027] By optimizing the lithium aluminum titanium phosphate matrix and Zr x Si 1-x The particle size of O2 / TiO2 can further improve the overall performance of the modified lithium aluminum titanium phosphate. In a preferred embodiment, the particle size D50 of the modified lithium aluminum titanium phosphate is 0.9 to 1.5 μm, and the Dmax is less than 10 μm. Furthermore, compared to other particle size ranges, limiting the particle size of the modified lithium aluminum titanium phosphate to this range further reduces pores and cracks on the surface of the modified lithium aluminum titanium phosphate material, thereby further improving the ionic conductivity of the modified phosphoric acid.

[0028] In a preferred embodiment, the ratio of the amount of the lithium aluminum titanium phosphate matrix to the coating layer is 1:(0.001-0.02). Compared with other ranges, limiting the ratio of the amount of the lithium aluminum titanium phosphate matrix to the coating layer within the above range is beneficial to further improve the capacity retention and thermal stability of the lithium aluminum titanium phosphate.

[0029] The second aspect of the present application provides a method for preparing the modified lithium titanium aluminum phosphate, which comprises: preparing a lithium titanium aluminum phosphate matrix; x Si 1-x O2 / TiO2 is physically coated to obtain modified lithium titanium aluminum phosphate.

[0030] The preparation method is simple, low-cost, and easy to industrialize and promote. The modified lithium aluminum titanium phosphate material prepared by the method has good capacity retention and high ionic conductivity.

[0031] The lithium aluminum titanium phosphate matrix can be prepared using a commonly used preparation method in the art. Preferably, the process for preparing the lithium aluminum titanium phosphate matrix includes: dry mixing, sintering, and first grinding a mixture of a lithium source compound, an aluminum source compound, a titanium source compound, and a phosphorus source compound in sequence to obtain the lithium aluminum titanium phosphate matrix.

[0032] In a preferred embodiment, the molar ratio of the Li element in the lithium source compound, the Al element in the aluminum source compound, the Ti element in the titanium source compound, and the P element in the phosphorus source compound is (1.3-1.35):0.3:1.7:3. The molar ratio of the Li element in the lithium source compound, the Al element in the aluminum source compound, the Ti element in the titanium source compound, and the P element in the phosphorus source compound includes but is not limited to the above range, and limiting it to the above range is beneficial to further improve the modified lithium aluminum titanium phosphate.

[0033] In order to improve the mixing uniformity of the reaction raw materials and thus improve their conversion rate, preferably, dry mixing includes: mixing the mixture of the lithium source compound, the aluminum source compound, the titanium source compound and the phosphorus source compound at a rotation speed of 200 to 400 rpm for 3 to 5 minutes, and then mixing at a rotation speed of 700 to 900 rpm for 3 to 5 minutes.

[0034] A lithium aluminum titanium phosphate matrix is ​​formed by a sintering process. Preferably, the sintering process is carried out in an air atmosphere at a sintering temperature of 800 to 950° C. for a constant temperature time of 6 to 15 hours. The first grinding comprises ultrafine grinding the sintered product using deionized water as a solvent to a particle size D50 of 0.5 to 0.6 μm.

[0035] In a preferred embodiment, the physical coating comprises: x Si 1-x The O2 / TiO2 mixture is subjected to a second grinding, spray drying, and pulverization in sequence to obtain modified lithium aluminum titanium phosphate. Spray drying after the second grinding is beneficial to improving the efficiency and effect of spray drying.

[0036] In a preferred embodiment, after the second grinding process, the lithium aluminum titanium phosphate matrix and the Zr x Si 1-x The D50 of the O2 / TiO2 mixture is 0.2-0.3 μm. x Si 1-x The O2 / TiO2 mixture D50 is limited to the above range, which can further improve the ionic conductivity and capacity retention rate of the modified lithium aluminum titanium phosphate prepared subsequently. x Si 1-xThe D50 of the O2 / TiO2 mixture is preferably 0.2 μm, 0.24 μm, 0.25 μm, 0.28 μm, 0.3 μm or a range formed by any two of the above values.

[0037] In a preferred embodiment, the spray drying conditions are an inlet air temperature of 220-250° C. and an outlet air temperature of 90-110° C. The inlet air temperature and outlet air temperature of the spray drying process include but are not limited to the above ranges, and limiting them to the above ranges is conducive to further improving the drying effect.

[0038] Preferably, the pulverization is performed by airflow pulverization. Airflow pulverization is performed in a sealed device, which reduces dust pollution and improves environmental friendliness. Furthermore, compared to mechanical pulverization, the product obtained after airflow pulverization has a more uniform particle size, a smoother surface, a regular shape, and better dispersibility. Preferably, after airflow pulverization, the particle size D50 is 0.9 to 1.5 μm, and Dmax is less than 10 μm.

[0039] The third aspect of the present application further provides a lithium-ion solid-state battery, comprising a solid-state electrolyte, wherein the solid-state electrolyte is the modified lithium aluminum titanium phosphate provided in the present application or is prepared by the above-mentioned preparation method.

[0040] The modified LATP material prepared in this application has the advantages of high ionic conductivity and capacity retention, good thermal stability, etc. Using it as a solid electrolyte to prepare lithium-ion solid-state batteries can greatly improve their comprehensive electrochemical performance during application.

[0041] The present application is further described in detail below with reference to specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in this application.

[0042] Example 1

[0043] A modified lithium aluminum titanium phosphate material and a preparation method thereof, comprising the following steps:

[0044] S1: Preparation of lithium aluminum titanium phosphate (LATP) material: lithium carbonate, aluminum oxide, titanium dioxide, and ammonium dihydrogen phosphate were weighed in a molar ratio of Li:Al:Ti:P of 1.3:0.3:1.7:3, and dry-mixed and sintered in sequence to obtain a pure LATP matrix material. The dry-mixing process was first mixed at a speed of 200 rpm for 3 minutes, and then mixed at a speed of 700 rpm for 3 minutes. The sintering process was sintered at a constant temperature of 800°C for 6 hours in an air atmosphere.

[0045] S2: The LATP matrix material prepared in step S1 is ultrafinely ground with water as solvent to a particle size D50 of 0.5 μm, and then mixed with Zr 0.1 Si 0.9 O2 / TiO2 material is mixed for coating, wherein Zr0.1 Si 0.9 O2 / TiO2 and Li 1.3 Al 0.3 Ti 1.7 The molar ratio of (PO4)3 is 0.001:1. After the coating process, it is ground to a particle size D50 of 0.2μm, and then spray-dried under the conditions of an inlet air temperature of 220℃ and an outlet air temperature of 90℃. Finally, the spray-dried material is air-pulverized to a particle size D50 of 0.9μm and Dmax of 5μm to obtain Zr 0.1 Si 0.9 O2 / TiO2 coated modified lithium aluminum titanium phosphate LATP material.

[0046] It should be noted that in this embodiment and subsequent embodiments, the solid electrolyte material needs to be made into a wafer sample to be tested, and the AC impedance of different response frequencies is recorded using an electrochemical workstation to analyze different electrode processes with different reaction time constants. The ionic conductivity of the material is obtained by fitting, analysis, and calculation. The above-mentioned modified LATP material is coated on the ternary LiNi 0.8 Co 0.1 Mn 0.1 The surface of O2 (NCM811) was coated with 0.05%, and the LATP-coated NCM811 was used as the positive electrode material, the battery-grade lithium sheet was used as the negative electrode material, and the main component was lithium hexafluorophosphate as the electrolyte. The simulated battery had a charge and discharge electrochemical window of 3.0-4.3V, and the specific capacity at 1C rate and the high-temperature cycle retention rate of 55°C / 1C rate were tested; and the differential scanning calorimetry peak temperature of the delithiation positive electrode was obtained by testing from room temperature to 400°C under compressed air at 10°C / min.

[0047] Example 2

[0048] A modified lithium aluminum titanium phosphate material and a preparation method thereof, comprising the following steps:

[0049] S1: Preparation of lithium aluminum titanium phosphate (LATP) material: lithium hydroxide, aluminum hydroxide, titanium dioxide, and diammonium hydrogen phosphate were weighed according to the element molar ratio of Li:Al:Ti:P of 1.32:0.3:1.7:3, and dry-mixed and sintered in sequence to obtain pure LATP matrix material. The dry-mixing process was first mixed at a speed of 250 rpm for 3 minutes, and then mixed at a speed of 750 rpm for 3.5 minutes; the sintering process was sintered at a constant temperature of 800°C for 8 hours in an air atmosphere.

[0050] S2: The LATP matrix material prepared in step S1 is ultrafinely ground with water as solvent to a particle size D50 of 0.52 μm and Zr 0.4 Si 0.6O2 / TiO2 material is mixed for coating, wherein Zr 0.4 Si 0.6 O2 / TiO2 and Li 1.3 Al 0.3 Ti 1.7 The molar ratio of (PO4)3 is 0.005:1. After the coating process is completed, it is further ground to a particle size D50 of 0.24μm, and then spray-dried under the conditions of an inlet air temperature of 230℃ and an outlet air temperature of 95℃. Finally, the spray-dried material is air-pulverized to a particle size D50 of 1.0μm and Dmax of 6μm to obtain Zr 0.4 Si 0.6 O2 / TiO2 coated modified lithium aluminum titanium phosphate LATP material.

[0051] Example 3

[0052] A modified lithium aluminum titanium phosphate material and a preparation method thereof, comprising the following steps:

[0053] S1: Preparation of lithium aluminum titanium phosphate (LATP) material: lithium carbonate, aluminum hydroxide, titanium dioxide, and diammonium hydrogen phosphate were weighed according to the element molar ratio of Li:Al:Ti:P of 1.325:0.3:1.7:3, and dry-mixed and sintered in sequence to obtain pure LATP matrix material. The dry-mixing process was first mixed at a speed of 300 rpm for 4 minutes, and then mixed at a speed of 800 rpm for 4 minutes; the sintering process was sintered at a constant temperature of 900°C for 1 hour in an air atmosphere.

[0054] S2: The LATP matrix material prepared in step S1 is ultrafinely ground with water as solvent to a particle size D50 of 0.55 μm, and then mixed with Zr 0.1 Si 0.9 O2 / TiO2 material is mixed for coating, wherein Zr 0.5 Si 0.5 O2 / TiO2 and Li 1.3 Al 0.3 Ti 1.7 The molar ratio of (PO4)3 is 0.01:1. After the coating process is completed, it is further ground to a particle size D50 of 0.25μm, and then spray-dried under the conditions of an inlet air temperature of 235℃ and an outlet air temperature of 100℃. Finally, the spray-dried material is air-pulverized to a particle size D50 of 1.2μm and Dmax of 7μm to obtain Zr 0.5 Si 0.5 O2 / TiO2 coated modified lithium aluminum titanium phosphate LATP material.

[0055] Example 4

[0056] A modified lithium aluminum titanium phosphate material and a preparation method thereof, comprising the following steps:

[0057] S1: Preparation of lithium aluminum titanium phosphate (LATP) material: lithium oxide, aluminum chloride, titanium dioxide, and diammonium hydrogen phosphate were weighed according to the element molar ratio of Li:Al:Ti:P of 1.31:0.3:1.7:3, and dry-mixed and sintered in sequence to obtain pure LATP matrix material. The dry-mixing process was first mixed at a speed of 250 rpm for 4.5 minutes, and then mixed at a speed of 900 rpm for 3 minutes; the sintering process was sintered at a constant temperature of 875°C for 10 hours in an air atmosphere.

[0058] S2: The LATP matrix material prepared in step S1 was ultrafinely ground with water as solvent to a particle size D50 of 0.58 μm, and then mixed with Zr 0.1 Si 0.9 O2 / TiO2 material is mixed for coating, wherein Zr 0.7 Si 0.3 O2 / TiO2 and Li 1.3 Al 0.3 Ti 1.7 The molar ratio of (PO4)3 is 0.015:1. After the coating process is completed, it is further ground to a particle size D50 of 0.28 μm, and then spray-dried at an inlet air temperature of 250 ° C and an outlet air temperature of 95 ° C. The air flow is crushed to a particle size D50 of 1.4 μm and Dmax of 8 μm to obtain Zr 0.7 Si 0.3 O2 / TiO2 coated modified lithium aluminum titanium phosphate LATP material.

[0059] Example 5

[0060] A modified lithium aluminum titanium phosphate material and a preparation method thereof, comprising the following steps:

[0061] S1: Preparation of lithium aluminum titanium phosphate (LATP) material: lithium oxide, aluminum oxide, titanium dioxide, and ammonium dihydrogen phosphate were weighed according to the element molar ratio of Li:Al:Ti:P of 1.35:0.3:1.7:3, and dry-mixed and sintered in sequence to obtain pure LATP matrix material. The dry-mixing process was first mixed at a speed of 350 rpm for 4.5 minutes, and then mixed at a speed of 750 rpm for 3.5 minutes; the sintering process was sintered at a constant temperature of 900°C for 7 hours in an air atmosphere.

[0062] S2: The LATP matrix material prepared in step S1 was ultrafinely ground with water as solvent to a particle size D50 of 0.56 μm, and then mixed with Zr 0.8 Si 0.2 O2 / TiO2 material is mixed for coating, wherein Zr 0.8 Si 0.2O2 / TiO2 and Li 1.3 Al 0.3 Ti 1.7 The molar ratio of (PO4)3 is 0.02:1. After the coating process, it is ground to a particle size D50 of 0.28μm, and then spray-dried under the conditions of an inlet air temperature of 240℃ and an outlet air temperature of 105℃. Finally, the spray-dried material is air-pulverized to a particle size D50 of 1.4μm and Dmax of 9μm to obtain Zr 0.8 Si 0.2 O2 / TiO2 coated modified lithium aluminum titanium phosphate LATP material.

[0063] Example 6

[0064] A modified lithium aluminum titanium phosphate material and a preparation method thereof, comprising the following steps:

[0065] S1: Preparation of lithium aluminum titanium phosphate (LATP) material: lithium oxide, aluminum chloride, titanium oxide, and diammonium hydrogen phosphate were weighed according to the element molar ratio of Li:Al:Ti:P of 1.35:0.3:1.7:3, and dry-mixed and sintered in sequence to obtain pure LATP matrix material. The dry-mixing process was first mixed at a speed of 400 rpm for 5 minutes, and then mixed at a speed of 900 rpm for 5 minutes; the sintering process was sintered at a constant temperature of 950°C for 15 hours in an air atmosphere.

[0066] S2: The LATP matrix material prepared in step S1 is ultra-finely ground with water as solvent to a particle size D50 of 0.6 μm, and then mixed with Zr 0.9 Si 0.1 O2 / TiO2 material is mixed for coating, wherein Zr 0.9 Si 0.1 O2 / TiO2 and Li 1.3 Al 0.3 Ti 1.7 The molar ratio of (PO4)3 is 0.02:1. After the coating process, it is ground to a particle size D50 of 0.3μm, and then spray-dried under the conditions of an inlet air temperature of 250℃ and an outlet air temperature of 110℃. Finally, the spray-dried material is air-pulverized to a particle size D50 of 1.5μm and Dmax of 10μm to obtain Zr 0.9 Si 0.1 O2 / TiO2 coated modified lithium aluminum titanium phosphate LATP material.

[0067] Example 7

[0068] The difference from Example 5 is that the coating layer is made of Zr x Si 1-x O2 / TiO2 composition, x is 0.1. The details are as follows:

[0069] S1: Preparation of lithium aluminum titanium phosphate (LATP) material: lithium oxide, aluminum oxide, titanium dioxide, and ammonium dihydrogen phosphate were weighed according to the element molar ratio of Li:Al:Ti:P of 1.35:0.3:1.7:3, and dry-mixed and sintered in sequence to obtain pure LATP matrix material. The dry-mixing process was first mixed at a speed of 350 rpm for 4.5 minutes, and then mixed at a speed of 750 rpm for 3.5 minutes; the sintering process was sintered at a constant temperature of 900°C for 7 hours in an air atmosphere.

[0070] S2: The LATP matrix material prepared in step S1 was ultrafinely ground with water as solvent to a particle size D50 of 0.56 μm, and then mixed with Zr 0.9 Si 0.1 O2 / TiO2 material is mixed for coating, wherein Zr 0.9 Si 0.1 O2 / TiO2 and Li 1.3 Al 0.3 Ti 1.7 The molar ratio of (PO4)3 is 0.02:1. After the coating process, it is ground to a particle size D50 of 0.28μm, and then spray-dried under the conditions of an inlet air temperature of 240℃ and an outlet air temperature of 105℃. Finally, the spray-dried material is air-pulverized to a particle size D50 of 1.4μm and Dmax of 9μm to obtain Zr 0.9 Si 0.1 O2 / TiO2 coated modified lithium aluminum titanium phosphate LATP material.

[0071] Example 8

[0072] The difference from Example 5 is that the coating layer is made of Zr x Si 1-x O2 / TiO2 composition, x is 0.3. The details are as follows:

[0073] S1: Preparation of lithium aluminum titanium phosphate (LATP) material: lithium oxide, aluminum oxide, titanium dioxide, and ammonium dihydrogen phosphate were weighed according to the element molar ratio of Li:Al:Ti:P of 1.35:0.3:1.7:3, and dry-mixed and sintered in sequence to obtain pure LATP matrix material. The dry-mixing process was first mixed at a speed of 350 rpm for 4.5 minutes, and then mixed at a speed of 750 rpm for 3.5 minutes; the sintering process was sintered at a constant temperature of 900°C for 7 hours in an air atmosphere.

[0074] S2: The LATP matrix material prepared in step S1 was ultrafinely ground with water as solvent to a particle size D50 of 0.56 μm, and then mixed with Zr 0.3 Si 0.7 O2 / TiO2 material is mixed for coating, wherein Zr 0.3 Si0.7 O2 / TiO2 and Li 1.3 Al 0.3 Ti 1.7 The molar ratio of (PO4)3 is 0.02:1. After the coating process, it is ground to a particle size D50 of 0.28μm, and then spray-dried under the conditions of an inlet air temperature of 240℃ and an outlet air temperature of 105℃. Finally, the spray-dried material is air-pulverized to a particle size D50 of 1.4μm and Dmax of 9μm to obtain Zr 0.3 Si 0.7 O2 / TiO2 coated modified lithium aluminum titanium phosphate LATP material.

[0075] Example 9

[0076] The difference from Example 5 is that the coating layer is made of Zr x Si 1-x O2 / TiO2 composition, x is 0.5. The details are as follows:

[0077] S1: Preparation of lithium aluminum titanium phosphate (LATP) material: lithium oxide, aluminum oxide, titanium dioxide, and ammonium dihydrogen phosphate were weighed according to the element molar ratio of Li:Al:Ti:P of 1.35:0.3:1.7:3, and dry-mixed and sintered in sequence to obtain pure LATP matrix material. The dry-mixing process was first mixed at a speed of 350 rpm for 4.5 minutes, and then mixed at a speed of 750 rpm for 3.5 minutes; the sintering process was sintered at a constant temperature of 900°C for 7 hours in an air atmosphere.

[0078] S2: The LATP matrix material prepared in step S1 was ultrafinely ground with water as solvent to a particle size D50 of 0.56 μm, and then mixed with Zr 0.5 Si 0.5 O2 / TiO2 material is mixed for coating, wherein Zr 0.5 Si 0.5 O2 / TiO2 and Li 1.3 Al 0.3 Ti 1.7 The molar ratio of (PO4)3 is 0.02:1. After the coating process, it is ground to a particle size D50 of 0.28μm, and then spray-dried under the conditions of an inlet air temperature of 240℃ and an outlet air temperature of 105℃. Finally, the spray-dried material is air-pulverized to a particle size D50 of 1.4μm and Dmax of 9μm to obtain Zr 0.5 Si 0.5 O2 / TiO2 coated modified lithium aluminum titanium phosphate LATP material.

[0079] Example 10

[0080] The difference from Example 5 is that the coating layer is made of Zrx Si 1-x O2 / TiO2 composition, x is 0.6. The details are as follows:

[0081] S1: Preparation of lithium aluminum titanium phosphate (LATP) material: lithium oxide, aluminum oxide, titanium dioxide, and ammonium dihydrogen phosphate were weighed according to the element molar ratio of Li:Al:Ti:P of 1.35:0.3:1.7:3, and dry-mixed and sintered in sequence to obtain pure LATP matrix material. The dry-mixing process was first mixed at a speed of 350 rpm for 4.5 minutes, and then mixed at a speed of 750 rpm for 3.5 minutes; the sintering process was sintered at a constant temperature of 900°C for 7 hours in an air atmosphere.

[0082] S2: The LATP matrix material prepared in step S1 was ultrafinely ground with water as solvent to a particle size D50 of 0.56 μm, and then mixed with Zr 0.6 Si 0.4 O2 / TiO2 material is mixed for coating, wherein Zr 0.6 Si 0.4 O2 / TiO2 and Li 1.3 Al 0.3 Ti 1.7 The molar ratio of (PO4)3 is 0.02:1. After the coating process, it is ground to a particle size D50 of 0.28μm, and then spray-dried under the conditions of an inlet air temperature of 240℃ and an outlet air temperature of 105℃. Finally, the spray-dried material is air-pulverized to a particle size D50 of 1.4μm and Dmax of 9μm to obtain Zr 0.6 Si 0.4 O2 / TiO2 coated modified lithium aluminum titanium phosphate LATP material.

[0083] Example 11

[0084] The difference from Example 5 is that the coating layer is made of Zr x Si 1-x O2 / TiO2 composition, x is 0.9. The details are as follows:

[0085] S1: Preparation of lithium aluminum titanium phosphate (LATP) material: lithium oxide, aluminum oxide, titanium dioxide, and ammonium dihydrogen phosphate were weighed according to the element molar ratio of Li:Al:Ti:P of 1.35:0.3:1.7:3, and dry-mixed and sintered in sequence to obtain pure LATP matrix material. The dry-mixing process was first mixed at a speed of 350 rpm for 4.5 minutes, and then mixed at a speed of 750 rpm for 3.5 minutes; the sintering process was sintered at a constant temperature of 900°C for 7 hours in an air atmosphere.

[0086] S2: The LATP matrix material prepared in step S1 was ultrafinely ground with water as solvent to a particle size D50 of 0.56 μm, and then mixed with Zr0.9 Si 0.1 O2 / TiO2 material is mixed for coating, wherein Zr 0.9 Si 0.1 O2 / TiO2 and Li 1.3 Al 0.3 Ti 1.7 The molar ratio of (PO4)3 is 0.02:1. After the coating process, it is ground to a particle size D50 of 0.28μm, and then spray-dried under the conditions of an inlet air temperature of 240℃ and an outlet air temperature of 105℃. Finally, the spray-dried material is air-pulverized to a particle size D50 of 1.4μm and Dmax of 9μm to obtain Zr 0.9 Si 0.1 O2 / TiO2 coated modified lithium aluminum titanium phosphate LATP material.

[0087] Example 12

[0088] The difference from Example 5 is that the particle size of the lithium aluminum titanium phosphate matrix after the first grinding is 0.5 μm, and the particle size of the lithium aluminum titanium phosphate matrix and the Zr x Si 1-x The particle size of the O2 / TiO2 mixture is 0.2 μm, and after air flow milling, D50 is 1.2 μm and Dmax is 7 μm.

[0089] Example 13

[0090] The difference from Example 5 is that the particle size of the lithium aluminum titanium phosphate matrix after the first grinding is 0.6 μm, and the particle size of the lithium aluminum titanium phosphate matrix and the Zr x Si 1-x The particle size of the O2 / TiO2 mixture is 0.3 μm, and after air flow milling, D50 is 1.2 μm and Dmax is 7 μm.

[0091] Example 14

[0092] The difference from Example 5 is that the particle size of the lithium aluminum titanium phosphate matrix after the first grinding is 0.3 μm, and the particle size of the lithium aluminum titanium phosphate matrix and the Zr x Si 1-x The particle size of the O2 / TiO2 mixture is 0.5 μm, and after air flow milling, D50 is 1.2 μm and Dmax is 7 μm.

[0093] Example 15

[0094] The difference from Example 14 is that after airflow crushing, D50 is 2 μm and Dmax is 12 μm.

[0095] Comparative Example 1

[0096] The only difference from Example 3 is that Zr 0.5 Si 0.5 O2 / TiO2 coating, other preparation processes are the same. Details are as follows:

[0097] A modified lithium aluminum titanium phosphate material and a preparation method thereof, comprising the following steps:

[0098] S1: Preparation of lithium aluminum titanium phosphate (LATP) material: lithium carbonate, aluminum hydroxide, titanium dioxide, and diammonium hydrogen phosphate were weighed according to the element molar ratio of Li:Al:Ti:P of 1.325:0.3:1.7:3, and dry-mixed and sintered in sequence to obtain pure LATP matrix material. The dry-mixing process was first mixed at a speed of 300 rpm for 4 minutes, and then mixed at a speed of 800 rpm for 4 minutes; the sintering process was sintered at a constant temperature of 900°C for 1 hour in an air atmosphere.

[0099] S2: The LATP matrix material obtained in step S1 is ultrafinely ground with water as solvent to a particle size D50 of 0.55 μm, and then further ground to a particle size D50 of 0.25 μm, and then spray-dried at an inlet air temperature of 235°C and an outlet air temperature of 100°C. Finally, the spray-dried material is air-pulverized to a particle size D50 of 1.2 μm and a Dmax of 7 μm to obtain Zr 0.5 Si 0.5 O2 / TiO2 coated modified lithium aluminum titanium phosphate LATP material.

[0100] Comparative Example 2

[0101] The only difference from Example 3 is that Zr 0.5 Si 0.5 O2 / TiO2 and Li 1.3 Al 0.3 Ti 1.7 The molar ratio of (PO4)3 is 0.025:1, and the other preparation processes are the same. The details are as follows:

[0102] S1: Preparation of lithium aluminum titanium phosphate (LATP) material: lithium carbonate, aluminum hydroxide, titanium dioxide, and diammonium hydrogen phosphate were weighed according to the element molar ratio of Li:Al:Ti:P of 1.325:0.3:1.7:3, and dry-mixed and sintered in sequence to obtain pure LATP matrix material. The dry-mixing process was first mixed at a speed of 300 rpm for 4 minutes, and then mixed at a speed of 800 rpm for 4 minutes; the sintering process was sintered at a constant temperature of 900°C for 1 hour in an air atmosphere.

[0103] S2: The LATP matrix material prepared in step S1 is ultrafinely ground with water as solvent to a particle size D50 of 0.55 μm, and then mixed with Zr 0.5 Si 0.5O2 / TiO2 material is mixed for coating, wherein Zr 0.5 Si 0.5 O2 / TiO2 and Li 1.3 Al 0.3 Ti 1.7 The molar ratio of (PO4)3 is 0.025:1. After the coating process is completed, it is further ground to a particle size D50 of 0.25μm, and then spray-dried under the conditions of an inlet air temperature of 235℃ and an outlet air temperature of 100℃. Finally, the spray-dried material is air-pulverized to a particle size D50 of 1.2μm and Dmax of 7μm to obtain Zr 0.5 Si 0.5 O2 / TiO2 coated modified lithium aluminum titanium phosphate LATP material.

[0104] Comparative Example 3

[0105] The only difference from Example 3 is that Zr 0.5 Si 0.5 O2 / TiO2 and Li 1.3 Al 0.3 Ti 1.7 The molar ratio of (PO4)3 is 0.0005:1, and the other preparation processes are the same. The details are as follows:

[0106] S1: Preparation of lithium aluminum titanium phosphate (LATP) material: lithium carbonate, aluminum hydroxide, titanium dioxide, and diammonium hydrogen phosphate were weighed according to the element molar ratio of Li:Al:Ti:P of 1.325:0.3:1.7:3, and dry-mixed and sintered in sequence to obtain pure LATP matrix material. The dry-mixing process was first mixed at a speed of 300 rpm for 4 minutes, and then mixed at a speed of 800 rpm for 4 minutes; the sintering process was sintered at a constant temperature of 900°C for 1 hour in an air atmosphere.

[0107] S2: The LATP matrix material prepared in step S1 is ultrafinely ground with water as solvent to a particle size D50 of 0.55 μm, and then mixed with Zr 0.5 Si 0.5 O2 / TiO2 material is mixed for coating, wherein Zr 0.5 Si 0.5 O2 / TiO2 and Li 1.3 Al 0.3 Ti 1.7 The molar ratio of (PO4)3 is 0.0005:1. After the coating process is completed, it is further ground to a particle size D50 of 0.25μm, and then spray-dried under the conditions of an inlet air temperature of 235℃ and an outlet air temperature of 100℃. Finally, the spray-dried material is air-pulverized to a particle size D50 of 1.2μm and Dmax of 7μm to obtain Zr 0.5 Si0.5 O2 / TiO2 coated modified lithium aluminum titanium phosphate LATP material.

[0108] Comparative Example 4

[0109] The only difference from Example 3 is the addition of Zr 0.5 Si 0.5 O2 / TiO2 and Li 1.3 Al 0.3 Ti 1.7 (PO4)3 was then ground to a particle size of D50 of 0.5 μm, and the rest of the preparation process was the same. Specific details are as follows:

[0110] S1: Preparation of lithium aluminum titanium phosphate (LATP) material: lithium carbonate, aluminum hydroxide, titanium dioxide, and diammonium hydrogen phosphate were weighed according to the element molar ratio of Li:Al:Ti:P of 1.325:0.3:1.7:3, and dry-mixed and sintered in sequence to obtain pure LATP matrix material. The dry-mixing process was first mixed at a speed of 300 rpm for 4 minutes, and then mixed at a speed of 800 rpm for 4 minutes; the sintering process was sintered at a constant temperature of 900°C for 1 hour in an air atmosphere.

[0111] S2: The LATP matrix material prepared in step S1 is ultrafinely ground with water as solvent to a particle size D50 of 0.55 μm, and then mixed with Zr 0.1 Si 0.9 O2 / TiO2 material is mixed for coating, wherein Zr 0.5 Si 0.5 O2 / TiO2 and Li 1.3 Al 0.3 Ti 1.7 The molar ratio of (PO4)3 is 0.01:1. After the coating process is completed, it is further ground to a particle size D50 of 0.5μm, and then spray-dried under the conditions of an inlet air temperature of 235℃ and an outlet air temperature of 100℃. Finally, the spray-dried material is air-pulverized to a particle size D50 of 1.2μm and Dmax of 7μm to obtain Zr 0.5 Si 0.5 O2 / TiO2 coated modified lithium aluminum titanium phosphate LATP material.

[0112] FIG1 shows the XRD patterns of the modified LATP material prepared in Example 3 and the LATP material prepared in Comparative Example 1.

[0113] Figure 2 is a SEM image of the modified LATP material prepared in Example 3 of the present application; Figure 3 is a SEM image of the LATP material prepared in Comparative Example 4 of the present application.

[0114] The ionic conductivity of the modified LATP material prepared in Example 3 is 3.72*10 -4S / cm, the differential scanning calorimetry peak temperature is 223.1℃, the specific capacity of LATP coated NCM811 material at 1C rate is 206.5mAh / g, and the 50-week high temperature cycle capacity retention rate is 99.46%, which is significantly better than the unmodified comparative example 1. 0.5 Si 0.5 O2 / TiO2 will affect the performance of LATP. The main reason is that the coating is less, the coating is uneven, and the material uniformity becomes worse. If the coating is more, the thickness becomes larger, resulting in a decrease in material performance. 0.5 Si 0.5 O2 / TiO2 coated LATP can improve the comprehensive performance of density, ionic conductivity, differential scanning calorimetry peak temperature (thermal stability) and so on only within the coating range of this solution. The coating of LATP material can improve the cycle performance and reduce the Ti 4+ With Ti 3+ The reaction can be used for ternary positive electrode coating to effectively increase the differential scanning calorimetry peak temperature and improve the capacity and thermal stability of the ternary material.

[0115] Table 1

[0116] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects: Zr x Si 1-x The coating layer formed by O2 / TiO2 on the surface of LATP material can effectively increase the ionic conductivity of LATP material. Its application in ternary cathode material can effectively increase the differential scanning calorimetry peak temperature, improve the capacity and thermal stability of ternary material. x Si 1-x The particle size of O2 / TiO2 is smaller than that of Li 1.3 Al 0.3 Ti 1.7 The particle size of (PO4)3 can make Zr x Si 1-x O2 / TiO2 is better coated on the surface of the LATP material, thereby reducing the voids and gaps on the surface of the modified lithium aluminum titanium phosphate material, thereby improving its ionic conductivity. On this basis, the modified LATP material with the above composition has the advantages of high ionic conductivity and capacity retention rate, as well as good thermal stability.

[0117] It should be noted that the terms "first," "second," and the like in the specification and claims of this application are used to distinguish similar objects, and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of the application described herein can, for example, be implemented in an order other than that described herein.

[0118] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A modified lithium aluminum titanium phosphate, characterized in that: The modified lithium aluminum titanium phosphate comprises a lithium aluminum titanium phosphate matrix and a coating layer, wherein the lithium aluminum titanium phosphate matrix is ​​composed of Li 1.3 Al 0.3 Ti 1.7 (PO4)3 represents, the coating layer is composed of Zr x Si 1-x O2 / TiO2 is formed, wherein x is 0.1 to 0.9, and the Zr x Si 1-x The particle size of O2 / TiO2 is smaller than that of Li 1.3 Al 0.3 Ti 1.7 Particle size of (PO4)3.

2. The modified lithium aluminum titanium phosphate according to claim 1, characterized in that The modified lithium aluminum titanium phosphate has a particle size D50 of 0.9 to 1.5 μm and a Dmax of less than 10 μm.

3. The modified lithium aluminum titanium phosphate according to claim 1, characterized in that The amount ratio of the lithium aluminum titanium phosphate matrix to the coating layer is 1:(0.001-0.02).

4. A method for preparing the modified lithium aluminum titanium phosphate according to claim 1, characterized in that: The preparation method of the modified lithium aluminum titanium phosphate comprises: Prepare the lithium aluminum titanium phosphate matrix according to claim 1; The lithium aluminum titanium phosphate matrix and Zr x Si 1-x O2 / TiO2 is physically coated to obtain the modified lithium aluminum titanium phosphate.

5. The method for preparing modified lithium aluminum titanium phosphate according to claim 4, characterized in that: The preparation of the lithium aluminum titanium phosphate matrix comprises: sequentially dry-mixing, sintering and first grinding a mixture of a lithium source compound, an aluminum source compound, a titanium source compound and a phosphorus source compound to obtain the lithium aluminum titanium phosphate matrix; The molar ratio of the Li element in the lithium source compound, the Al element in the aluminum source compound, the Ti element in the titanium source compound, and the P element in the phosphorus source compound is (1.3-1.35):0.3:1.7:

3.

6. The method for preparing modified lithium aluminum titanium phosphate according to claim 5, characterized in that: The dry mixing process comprises: mixing the mixture of the lithium source compound, the aluminum source compound, the titanium source compound and the phosphorus source compound at a rotation speed of 200 to 400 rpm for 3 to 5 minutes, and then mixing at a rotation speed of 700 to 900 rpm for 3 to 5 minutes.

7. The method for preparing modified lithium aluminum titanium phosphate according to claim 5, characterized in that: The sintering process is carried out in an air atmosphere, and the sintering temperature is 800-950° C., and the constant temperature time is 6-15 hours.

8. The method for preparing modified lithium aluminum titanium phosphate according to claim 5, characterized in that: The first grinding includes ultrafine grinding the sintered product using deionized water as a solvent until the particle size D50 is 0.5 to 0.6 um.

9. The method for preparing modified lithium aluminum titanium phosphate according to any one of claims 4 to 8, characterized in that: The physical coating comprises: x Si 1-x The mixture of O2 / TiO2 is sequentially subjected to a second grinding, spray drying and pulverization to obtain the modified lithium aluminum titanium phosphate; After the second grinding, the particle size D50 of the mixture is 0.2-0.3 μm; The spray drying conditions are as follows: the air inlet temperature is 220-250°C and the air outlet temperature is 90-110°C; The pulverization is air flow pulverization. After the pulverization, the particle size D50 of the particles is 0.9-1.5 μm, and Dmax is less than 10 μm.

10. A lithium ion solid-state battery, comprising a solid electrolyte, characterized in that: The solid electrolyte is the modified lithium aluminum titanium phosphate according to any one of claims 1 to 3 or is prepared by the preparation method according to any one of claims 4 to 9.

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