Core-shell type glassy solid electrolyte, method for preparing the same, and use

Abstract

This disclosure provides a composite material. The composite material is LiAlPO4(OH) x F 1-x And LiAlPO4(OH) x F 1-x The composite solid electrolyte material comprises Al(H2PO4)3 composited on the surface of a material, where x satisfies 0 ≤ x ≤ 1. The present disclosure further prepares a core-shell type glassy solid electrolyte material. The composite solid electrolyte has excellent ionic conductivity, good flexibility, a stable composite structure, and excellent thermal stability. When used as a coating for a positive electrode, it suppresses the reduction in positive electrode capacity due to the coating layer, effectively removes alkaline lithium remaining on the surface during the preparation process of the positive electrode material, and converts the remaining lithium into Li3PO4, which can contribute to the ionic conductivity of the coating layer, and AlPO4, which can protect the positive electrode. Furthermore, Li3AlF6 is more stable with respect to HF, and its glassy structure has excellent flexibility, which can contribute to effective interfacial contact between the positive electrode and the electrolyte and electrolyte solution, thereby achieving good interfacial ion conduction.

Description

Technical Field

[0001] The present disclosure belongs to the technical field of lithium-ion battery cathode coating materials, and relates to composite materials and their uses, core-shell glassy solid electrolyte materials, their preparation methods and uses, as well as lithium-ion battery coated cathode materials and their preparation methods.

[0002] Cross-reference to related applications The present disclosure claims priority based on a Chinese application filed with the Chinese Patent Office on June 5, 2023, with application number 202310656074.X and title "Core-shell Glassy Solid Electrolyte, Its Preparation Method and Use", and all of its content is incorporated herein by reference.

Background Art

[0003] To meet the energy demands of electric vehicles and smart grid societies, research on secondary batteries with higher energy and power densities is underway. Lithium-ion batteries (LIBs) show promise in such large-scale battery applications. To ensure sufficient energy density and safe operating conditions of the battery, all-solid-state lithium-ion batteries with non-flammable inorganic solids as electrolytes have attracted attention. Solid electrolytes with high Li + conductivity play an important role in high-performance all-solid-state lithium-ion batteries. With the development and research of various solid electrolytes, solid electrolytes are becoming increasingly important in secondary lithium batteries. Solid electrolytes are not limited to use in all-solid-state batteries, but can solve various problems in the application of electrolytes as additives for solid-liquid mixed electrolytes, improve the stability of separators as coating materials for separators to ensure battery safety, solve interface problems between cathodes and anodes and electrolytes or electrolytes as coating materials for cathode materials and anode materials, and suppress the generation of lithium dendrites from different mechanisms to improve the cycle stability of the battery. In view of this, solid electrolytes have high Li +Conductivity, good electrochemical stability, air stability, and excellent mechanical performance are required.

[0004] Several lithium compounds, such as oxides, sulfides, halides, and polymers, have been taught as promising solid electrolyte materials. However, as research into various compounds progresses, their respective drawbacks become apparent, significantly impacting their applications. In applications of cathodes coated with solid electrolytes, the solid electrolyte acts as a physical barrier, suppressing side reactions, reducing the dissolution of transition metals, improving electronic and ionic conductivity, achieving surface chemical modification, promoting interfacial ionic charge transitions, stabilizing the structure, and reducing phase transition stress. Different solid electrolytes have different coating effects, and it is not possible to perfectly achieve all of the above technical effects. Furthermore, coating a cathode with a solid electrolyte can lead to a decrease in cathode capacity. Additionally, alkaline lithium remaining on the surface during the cathode preparation process reacts during the battery's charge and discharge process to generate gas, compromising battery safety. Therefore, the removal of lithium remaining on the surface is also expected from solid electrolytes.

[0005] Research suggests that fluorides have potential as novel materials for solid electrolytes and can largely meet the practical requirements for solid electrolytes used in batteries. Furthermore, fluorides are considered to have almost the widest electrochemical window, allowing for the combined use of high-voltage positive electrode and low-operating-voltage negative electrode materials, contributing to improved energy density in batteries. For example, Li3AlF6 is a promising fluoride solid lithium + It is considered a conductor. Li3AlF6 is a stoichiometric compound of LiF and AlF3 with a molar ratio of 3:1. At room temperature, Li3AlF6 has a monoclinic crystal structure and is called β-Li3AlF6. At room temperature, β-Li3AlF6 itself contains Li + It has relatively poor conductivity and limited cycle stability. While glassy amorphous Li3AlF6 shows significant improvements in ionic conductivity and electrochemical performance, there are teachings that its performance at room temperature still falls short of practical application requirements.

[0006] Therefore, finding a more suitable fluoride that can solve the above problems existing in Li3AlF6 has become the focus of research in the industry and related enterprises.

[0007] In view of this, the present disclosure is provided.

Summary of the Invention

[0008] In view of this, the technical problem to be solved by the present disclosure is to provide a composite material and its use, a core-shell type glassy solid electrolyte material, its preparation method and use, as well as a lithium-ion battery-coated cathode material and its preparation method. The core-shell type glassy solid electrolyte material according to the present disclosure can effectively improve the surface performance of the cathode material, protect the cathode material from the influence of HF, suppress the dissolution of transition metals in the cathode material, and ensure that the cathode exhibits relatively good electrochemical performance. And its preparation method is simple and easy to implement, with mild conditions, high controllability, excellent stability, and is more easily popularized and used in mass production.

[0009] The present disclosure provides a composite material. The composite material includes LiAlPO4(OH) x F 1-x and Al(H2PO4)3 composite on the surface of LiAlPO4(OH) x F 1-x , where x satisfies 0 ≦ x ≦ 1.

[0010] In another embodiment of the present disclosure, the composite material has a core-shell structure, where LiAlPO4(OH) x F 1-x is the core, and Al(H2PO4)3 is the shell layer. The thickness of Al(H2PO4)3 as the shell layer is 10 nm to 50 nm, the particle size of the composite material is 80 nm to 600 nm, and the mass ratio of LiAlPO4(OH) x F 1-x to Al(H2PO4)3 is (30 - 65):(0.5 - 3).

[0011] This disclosure provides the use of composite materials in solid electrolyte materials or lithium-ion batteries according to one of the above technical proposals.

[0012] In other embodiments of the present disclosure, the solid electrolyte material includes a fluorine-based solid electrolyte material, the fluorine-based solid electrolyte material includes a glassy fluorine-based solid electrolyte material, and the glassy fluorine-based solid electrolyte material includes Li3AlF6.

[0013] This disclosure further provides a core-shell type glassy solid electrolyte material. The core-shell type glassy solid electrolyte material comprises Li3AlF6 and a composite material compounded with Li3AlF6 as raw materials, wherein the composite material includes a composite material according to any one of the above technical proposals.

[0014] In other embodiments of the present disclosure, Li3AlF6 in the core-shell glassy solid electrolyte material is a base material, and the composite material compounded with Li3AlF6 is specifically a composite material dispersed in Li3AlF6, and the Li3AlF6 and LiAlPO4(OH) in the composite material x F 1-x The mass ratio of is (5-30):(30-65), and the core-shell type glassy solid electrolyte material includes core-shell type glassy solid electrolyte materials used in lithium-ion batteries.

[0015] In other embodiments of the present disclosure, the raw materials further comprise SiO2 and / or Al2O3, wherein the SiO2 and / or Al2O3 are dispersed in the Li3AlF6, and the mass ratio of the SiO2 and / or Al2O3 to the Li3AlF6 is (0.03~0.3):(5~30), and the lithium-ion battery specifically comprises a coating material for the lithium-ion battery cathode material.

[0016] This disclosure provides a method for preparing a core-shell type glassy solid electrolyte material. The preparation method involves LiAlPO4(OH) x F 1-xThe method includes: (1) mixing a slurry with Al(H2PO4)3 to obtain a slurry where x satisfies 0 ≤ x ≤ 1, premixing LiF and AlF3, performing a first sintering to obtain a glassy Li3AlF6 material, and then polishing to obtain glassy Li3AlF6 powder; and (2) performing a second mixing of the glassy Li3AlF6 powder obtained in step (1), SiO2 and / or Al2O3 powder, and the slurry to obtain a mixed slurry, and then vacuum drying to obtain the core-shell type glassy solid electrolyte material.

[0017] In other embodiments of this disclosure, the LiAlPO4(OH) x F 1-x The slurry is LiAlPO4(OH) x F 1-x The material is obtained by polishing, and the polishing method includes wet polishing, the rotational speed of the polishing is 500 r / min to 2500 r / min, and the polishing time is 2 hours to 10 hours.

[0018] In other embodiments of the present disclosure, the mixing time is 30 to 600 minutes, the molar ratio of LiF to AlF3 is (3.0 to 3.3):1, the premixing method includes mixing by planetary ball milling, the premixing time is 4 to 12 hours, and the rotation speed of the premixing is 200 r / min to 500 r / min.

[0019] In other embodiments of the present disclosure, the premixing is followed by a drying step, wherein the drying temperature is 80°C to 200°C, the drying time is 2 hours to 24 hours, the first sintering temperature is 600°C to 950°C, and the first sintering time is 5 minutes to 180 minutes.

[0020] In other embodiments of the present disclosure, the process further includes a quenching step after the first sintering, wherein the quenching method includes water quenching or cooling with liquid nitrogen, and the particle size of the glassy Li3AlF6 powder is 100 nm to 400 nm.

[0021] In other embodiments of the present disclosure, the second mixing specifically involves first mixing the glassy Li3AlF6 powder with the slurry, and then further mixing with the SiO2 and / or Al2O3 powder, wherein the first mixing time is 30 to 300 minutes, the further mixing time is 2 to 24 hours, the vacuum drying temperature is 100°C to 300°C, and the vacuum drying time is 3 to 48 hours.

[0022] This disclosure provides for the use of a core-shell type glassy solid electrolyte material in a lithium-ion battery, either by any one of the above-described technical proposals or by a preparation method according to any one of the above-described technical proposals.

[0023] In other embodiments of the present disclosure, the lithium-ion battery specifically includes a lithium-ion battery cathode material, and the use specifically refers to the use of the lithium-ion battery cathode material in a coating material.

[0024] This disclosure provides a lithium-ion battery coated cathode material. The lithium-ion battery coated cathode material comprises a cathode material and a core-shell type glassy solid electrolyte material coated on the cathode material.

[0025] The core-shell type glassy solid electrolyte material includes a core-shell type glassy solid electrolyte material prepared according to any one of the above technical proposals or a core-shell type glassy solid electrolyte material prepared by the preparation method according to any one of the above technical proposals.

[0026] In other embodiments of this disclosure, the mass ratio of the positive electrode material to the core-shell type glassy solid electrolyte material is 1:(0.02~0.15), and the thickness of the coating layer of the core-shell type glassy solid electrolyte material is 0.6 μm~1.2 μm.

[0027] This disclosure provides a method for preparing a coated cathode material for lithium-ion batteries. The preparation method includes the steps of mixing a cathode material, a polished core-shell type glassy solid electrolyte material, and a solvent, and then performing a second sintering to obtain a coated cathode material coated with a core-shell type glassy solid electrolyte, wherein the core-shell type glassy solid electrolyte material includes a core-shell type glassy solid electrolyte material prepared by any one of the above technical proposals or a core-shell type glassy solid electrolyte material prepared by the preparation method of any one of the above technical proposals.

[0028] In other embodiments of the present disclosure, the powder particle size D50 of the polished core-shell type glassy solid electrolyte material is 0.4 μm to 1.0 μm, the specific steps of mixing are to first disperse the cathode material and the solvent by ultrasonic stirring, and then add the polished core-shell type glassy solid electrolyte material and stir-mix, the solvent being anhydrous ethanol and / or N-methylpyrrolidone, the ultrasonic stirring dispersion time being 20 minutes to 120 minutes, and the stirring mixing time being 2 hours to 24 hours.

[0029] In other embodiments of the present disclosure, the mixture is followed by a drying step, wherein the drying temperature is 80°C to 200°C, the drying time is 2 to 12 hours, the second sintering temperature is 200°C to 400°C, and the holding time for the second sintering is 2 to 12 hours.

[0030] This disclosure has the following beneficial effects, for example:

[0031] This disclosure provides a composite material. The composite material is LiAlPO4(OH) x F 1-x And LiAlPO4(OH) x F 1-xThe composite material comprises Al(H2PO4)3 compounded on its surface, where x satisfies 0 ≤ x ≤ 1. Compared to the prior art, this disclosure designs a composite material having a specific composition and structure, and further forms a core-shell type glassy solid electrolyte material by combining the composite material with a material such as Li3AlF6 based on a specific mixing ratio and structure.

[0032] The core-shell type glassy solid electrolyte prepared in this disclosure has a core portion of LiAlPO4(OH) x F 1-x This material, when used as a coating for the positive electrode, assists in the storage of lithium ions in the positive electrode material, suppresses the side effects on the positive electrode capacity caused by coating with a solid electrolyte, and has a relatively high lithium ion diffusion coefficient and a stable structure. The shell portion is made of Al(H2PO4)3 material, and hydrogen bonds exist in Al(H2PO4)3, which provide a strong structure for adhesion between one crystal surface and another, LiAlPO4(OH) x F 1-x F has relatively high electronegativity in both Li3AlF6. - Because it has hydrogen bonds, it can bond with hydrogen bonds to obtain a stable core-shell type glassy structure, improving the processability of the solid electrolyte. During the heating process, hydrogen bonds still exist, maintaining structural stability. Furthermore, when the Al(H2PO4)3 material of the shell portion is used as a coating for the positive electrode, it decomposes during the heating process to produce Al(PO3)3, and Al(PO3)3 reacts with alkaline lithium, Li2CO3 or LiOH, remaining on the surface of the positive electrode material to produce ionic conductive Li3PO4 and an AlPO4 coating layer that protects the positive electrode.

[0033] The core-shell type glassy solid electrolyte prepared in this disclosure uses Li3AlF6 as the base material, and by obtaining a completely glassy Li3AlF6 through quenching, the problem of poor lithium ion conductivity in the Li3AlF6 crystal structure is effectively improved, and LiAlPO4(OH) x F 1-x PO4 in 3-When freed into the glassy Li3AlF6 region, it plays a role in the conduction of lithium ions based on the law of charge conservation in the region, and the Li3AlF6 material has excellent ionic conductivity. Because glassy Li3AlF6 has relatively good flexibility, it can contribute to improving the interfacial contact problem between the positive electrode and the electrolyte or electrolyte solution, and therefore, due to its relatively good ionic conductivity, it can effectively improve the interfacial performance of the positive electrode. Furthermore, Li3AlF6 itself is a relatively stable material and does not react with HF, so it can coat the positive electrode to protect it from corrosion by HF and prevent a decrease in the positive electrode capacity due to the dissolution of transition metals. In addition, because Li3AlF6 has a relatively wide electrochemical window, it can ensure the use of high-voltage positive electrodes without decomposition. Furthermore, the core-shell type glassy solid electrolyte contains trace amounts of glassy stable compounds, such as SiO2 and / or Al2O3 material, which function as a "skeleton" of the glassy material, suppressing the tendency of the glassy material to crystallize during the sintering process in the positive electrode coating process, and improving the chemical and thermal stability of the glassy material.

[0034] The core-shell type glassy composite solid electrolyte according to this disclosure has excellent ionic conductivity, good flexibility, a stable composite structure, and excellent thermal stability. When this solid electrolyte is used as a coating for a positive electrode, the decrease in positive electrode capacity caused by the coating layer can be suppressed, which is a feature not found in other positive electrode coating layers. Compared to other solid electrolytes as positive electrode coating materials, the core-shell type glassy composite solid electrolyte according to this disclosure can effectively remove alkaline lithium remaining on the surface during the preparation process of the positive electrode material, and the remaining lithium can be converted into Li3PO4, which can contribute to the ionic conductivity of the coating layer, and AlPO4, which can protect the positive electrode. Furthermore, the Li3AlF6 in the solid electrolyte prepared in this disclosure is more stable with respect to HF than other positive electrode coating materials, and its glassy structure has excellent flexibility, which can contribute to effective interfacial contact between the positive electrode and the electrolyte and electrolyte solution, enabling good ionic conductivity at the interface, which is a feature not found in other positive electrode coating layers. Therefore, when the core-shell type glassy composite solid electrolyte prepared in this disclosure is used as a coating for a positive electrode, it can achieve several technical effects that cannot be simultaneously realized with other coating layers.

[0035] To more clearly explain the technical concepts of the embodiments of this disclosure, the drawings used in the embodiments are briefly described below. The drawings described are merely illustrative of some embodiments of this disclosure and do not limit the scope. Those skilled in the art can obtain other relevant drawings based on these drawings without inventive ability. [Brief explanation of the drawing]

[0036] [Figure 1] This is a schematic diagram of the core-shell type glassy solid electrolyte relating to this disclosure. [Figure 2] This is an SEM image of the core-shell type glassy solid electrolyte prepared in Example 1 of this disclosure. [Modes for carrying out the invention]

[0037] The endpoints and any values ​​of the ranges disclosed herein are not limited to those specific ranges or values, and these ranges or values ​​should be understood to include values ​​close to those ranges or values. In the case of numerical ranges, one or more new numerical ranges can be obtained by combinations of the endpoints of each range, combinations of the endpoints of each range and individual specific values, and combinations of individual specific values, and these numerical ranges should also be considered to be specifically disclosed herein.

[0038] To further illustrate the present disclosure, optional embodiments of the present disclosure have been described below using examples, but these descriptions are solely for the purpose of illustrating the features and advantages of the present disclosure and do not limit the scope of the claims of the present disclosure.

[0039] All raw materials relating to this disclosure are not limited in their source of acquisition and may be commercially available or prepared by methods commonly known to those skilled in the art.

[0040] All raw materials relating to this disclosure are not particularly limited in purity, and may be of industrial purity or purity commonly used in the field of lithium-ion solid electrolyte preparation.

[0041] This disclosure provides a composite material. The composite material is LiAlPO4(OH) x F 1-x And LiAlPO4(OH) x F 1-x The surface contains Al(H2PO4)3 compounded with a material, where x satisfies 0 ≤ x ≤ 1.

[0042] In this disclosure, x satisfies 0 ≤ x ≤ 1, or 0.2 ≤ x ≤ 0.8, or 0.4 ≤ x ≤ 0.6.

[0043] In this disclosure, optionally, the composite material has a core-shell structure.

[0044] In this disclosure, optionally, the LiAlPO4(OH) x F1-x The core is, and optionally, the Al(H2PO4)3 is the shell layer.

[0045] In this disclosure, the thickness of the Al(H2PO4)3 as a shell layer is optionally 10 nm to 50 nm, optionally 15 nm to 45 nm, optionally 20 nm to 40 nm, and optionally 25 nm to 35 nm.

[0046] In this disclosure, the particle size of the composite material is optionally 80 nm to 600 nm, optionally 150 nm to 500 nm, and optionally 250 nm to 400 nm.

[0047] In this disclosure, the LiAlPO4(OH) x F 1-x The mass ratio of to Al(H2PO4)3 is, arbitrarily, (30-65):(0.5-3), arbitrarily, (40-55):(0.5-3), and arbitrarily, (30-65):(1.5-2).

[0048] This disclosure provides the use of composite materials in solid electrolyte materials or lithium-ion batteries according to one of the above technical proposals.

[0049] In this disclosure, the solid electrolyte material optionally includes, but is not limited to, fluorine-based solid electrolyte materials.

[0050] In this disclosure, the fluorine-based solid electrolyte material optionally includes, but is not limited to, glassy fluorine-based solid electrolyte materials.

[0051] In this disclosure, the glassy fluorine-based solid electrolyte material optionally includes, but is not limited to, Li3AlF6.

[0052] This disclosure provides a core-shell type glassy solid electrolyte material. The core-shell type glassy solid electrolyte material comprises Li3AlF6 and a composite material compounded with Li3AlF6 as its raw materials.

[0053] In this disclosure, optionally, the composite material includes a composite material according to any one of the above-described technical proposals.

[0054] In this disclosure, Li3AlF6 in the core-shell type glassy solid electrolyte material is optionally a base material.

[0055] In this disclosure, optionally, the composite material compounded with Li3AlF6 is specifically a composite material dispersed in Li3AlF6.

[0056] In this disclosure, the Li3AlF6 and the LiAlPO4(OH) in the composite material x F 1-x The mass ratios are, arbitrarily, (5-30):(30-65), arbitrarily, (10-25):(30-65), and arbitrarily, (10-20):(40-55).

[0057] In this disclosure, optionally, the core-shell type glassy solid electrolyte material includes a core-shell type glassy solid electrolyte material used in lithium-ion batteries.

[0058] In this disclosure, in the core-shell type glassy solid electrolyte material according to the above-described technical proposal, the raw materials optionally further comprise SiO2 and / or Al2O3.

[0059] In this disclosure, optionally, the SiO2 and / or Al2O3 are dispersed in Li3AlF6.

[0060] In this disclosure, the mass ratio of SiO2 and / or Al2O3 to Li3AlF6 is optionally (0.03~0.3):(5~30), optionally (0.08~0.25):(5~30), optionally (0.1~0.2):(10~25), and optionally (0.12~0.18):(10~20).

[0061] In this disclosure, optionally, the lithium-ion battery specifically includes a coating material for the lithium-ion battery cathode material.

[0062] This disclosure provides a method for preparing a core-shell type glassy solid electrolyte material. The preparation method includes the following steps.

[0063] (1) LiAlPO4(OH) x F 1-x The slurry is mixed with Al(H2PO4)3 to obtain a slurry.

[0064] Here, x satisfies 0 ≤ x ≤ 1.

[0065] After pre-mixing LiF and AlF3, the first sintering is performed to obtain a glassy Li3AlF6 material, which is then polished to obtain glassy Li3AlF6 powder.

[0066] (2) The glassy Li3AlF6 powder obtained in the above step is mixed a second time with the SiO2 and / or Al2O3 powder and the slurry to obtain a mixed slurry, which is then vacuum dried to obtain a core-shell type glassy solid electrolyte material.

[0067] This disclosure first concerns LiAlPO4(OH) x F 1-x The slurry is mixed with Al(H2PO4)3 to obtain a mixed slurry.

[0068] Here, x satisfies 0 ≤ x ≤ 1.

[0069] After pre-mixing LiF and AlF3, drying is performed and the first sintering is carried out to obtain a glassy Li3AlF6 material, which is then polished to obtain glassy Li3AlF6 powder.

[0070] In this disclosure, optionally, the LiAlPO4(OH) x F 1-x The slurry is LiAlPO4(OH) x F 1-x This was obtained by polishing the material.

[0071] In this disclosure, the polishing method may optionally include, but is not limited to, wet polishing.

[0072] In this disclosure, the rotational speed of the polishing is optionally 500 r / min to 2500 r / min, optionally 900 r / min to 2100 r / min, and optionally 1300 r / min to 1700 r / min.

[0073] In this disclosure, the polishing time is optionally 2 to 10 hours, optionally 3 to 9 hours, optionally 4 to 8 hours, or optionally 5 to 7 hours.

[0074] In this disclosure, the molar ratio of LiF to AlF3 is optionally (3.0-3.3):1, optionally (3.05-3.25):1, and optionally (3.1-3.2):1.

[0075] In this disclosure, the premixing method may optionally include, but is not limited to, mixing by planetary ball milling.

[0076] In this disclosure, the premixing time is optionally 4 to 12 hours, optionally 4 to 11 hours, optionally 5 to 10 hours, optionally 6 to 9 hours, and optionally 7 to 8 hours.

[0077] In this disclosure, the rotational speed of the premixing is optionally 200 r / min to 500 r / min, optionally 250 r / min to 450 r / min, and optionally 300 r / min to 400 r / min.

[0078] In this disclosure, the drying temperature is optionally 80°C to 200°C, optionally 100°C to 180°C, and optionally 120°C to 160°C.

[0079] In this disclosure, the drying time is optionally 2 to 24 hours, optionally 5 to 20 hours, and optionally 10 to 15 hours.

[0080] In this disclosure, the temperature of the first sintering is optionally 600°C to 950°C, optionally 700°C to 900°C, and optionally 750°C to 800°C.

[0081] In this disclosure, the duration of the first sintering is optionally 5 to 180 minutes, optionally 15 to 120 minutes, and optionally 30 to 80 minutes.

[0082] In this disclosure, optionally, the step of quenching is further included after the first sintering.

[0083] In this disclosure, the quenching method may optionally include, but is not limited to, water quenching or cooling with liquid nitrogen.

[0084] In this disclosure, the particle size of the glassy Li3AlF6 powder is optionally 100 nm to 400 nm, optionally 150 nm to 350 nm, and optionally 200 nm to 300 nm.

[0085] In this disclosure, the final step involves a second mixing of the glassy Li3AlF6 powder obtained in the above step with SiO2 and / or Al2O3 powder and a mixture to obtain a mixed slurry, and then sintering to obtain a core-shell type glassy solid electrolyte material.

[0086] In this disclosure, optionally, the second mixing procedure involves first mixing the glassy Li3AlF6 powder with the slurry, and then further mixing it with SiO2 and / or Al2O3 powder.

[0087] In this disclosure, the initial mixing time is optionally 30 to 300 minutes, optionally 80 to 250 minutes, or optionally 120 to 200 minutes.

[0088] In this disclosure, the further mixing time is optionally 2 to 24 hours, optionally 7 to 20 hours, or optionally 12 to 15 hours.

[0089] In this disclosure, the vacuum drying temperature is optionally 100°C to 300°C, optionally 140°C to 260°C, and optionally 180°C to 220°C.

[0090] In this disclosure, the vacuum drying time is optionally 3 to 48 hours, optionally 13 to 38 hours, and optionally 23 to 28 hours.

[0091] In this disclosure, the final sintering step does not affect the overall composition and mixing ratio of the material; therefore, the composition and mixing ratio of the raw materials in the preparation method can be considered as the composition and mixing ratio of the final core-shell type glassy solid electrolyte material.

[0092] This disclosure provides for the use of a core-shell type glassy solid electrolyte material in a lithium-ion battery, either by any one of the above-described technical proposals or by a preparation method according to any one of the above-described technical proposals.

[0093] In this disclosure, optionally, the lithium-ion battery specifically includes a lithium-ion battery cathode material.

[0094] In this disclosure, optionally, the use is specifically the use in a coating material for lithium-ion battery cathode materials.

[0095] This disclosure provides a lithium-ion battery coated cathode material. The lithium-ion battery coated cathode material comprises a cathode material and a core-shell type glassy solid electrolyte material coated on the cathode material.

[0096] In this disclosure, the core-shell type glassy solid electrolyte material includes a core-shell type glassy solid electrolyte material prepared by any one of the above technical proposals or a core-shell type glassy solid electrolyte material prepared by a preparation method according to any one of the above technical proposals.

[0097] In this disclosure, in the lithium-ion battery coated cathode material according to the above-described technical proposal, the mass ratio of the cathode material to the core-shell type glassy solid electrolyte material is optionally 1:(0.02~0.15), optionally 1:(0.05~0.13), and optionally 1:(0.08~0.10).

[0098] In this disclosure, the thickness of the coating layer of the core-shell type glassy solid electrolyte material is optionally 0.6 μm to 1.2 μm, optionally 0.8 μm to 1.1 μm, and optionally 0.9 μm to 1.0 μm.

[0099] This disclosure provides a method for preparing a coated cathode material for lithium-ion batteries. The preparation method includes the steps of mixing a cathode material, a polished core-shell type glassy solid electrolyte material, and a solvent, and then performing a second sintering to obtain a coated cathode material coated with a core-shell type glassy solid electrolyte.

[0100] In this disclosure, the core-shell type glassy solid electrolyte material includes a core-shell type glassy solid electrolyte material prepared by any one of the above technical proposals or a core-shell type glassy solid electrolyte material prepared by a preparation method according to any one of the above technical proposals.

[0101] In this disclosure, the powder particle size D50 of the polished core-shell type glassy solid electrolyte material is optionally 0.4 μm to 1.0 μm, optionally 0.6 μm to 0.9 μm, and optionally 0.7 μm to 0.8 μm.

[0102] In this disclosure, optionally, the specific steps of the mixing include first dispersing the cathode material and solvent by ultrasonic stirring, and then adding the polished core-shell type glassy solid electrolyte material and stirring and mixing.

[0103] In this disclosure, the solvent optionally comprises anhydrous ethanol and / or N-methylpyrrolidone, and optionally comprises anhydrous ethanol or N-methylpyrrolidone.

[0104] In this disclosure, the time for dispersion by ultrasonic stirring is optionally 20 to 120 minutes, optionally 40 to 100 minutes, and optionally 60 to 80 minutes.

[0105] In this disclosure, the stirring and mixing time is optionally 2 to 24 hours, optionally 7 to 20 hours, or optionally 11 to 16 hours.

[0106] In this disclosure, optionally, the further step may include drying after the mixing.

[0107] In this disclosure, the drying temperature is optionally 80°C to 200°C, optionally 100°C to 180°C, and optionally 120°C to 160°C.

[0108] In this disclosure, the drying time is optionally 2 to 12 hours, optionally 4 to 10 hours, or optionally 6 to 8 hours.

[0109] In this disclosure, the temperature of the second sintering is optionally 200°C to 400°C, optionally 250°C to 350°C, and optionally 280°C to 330°C.

[0110] In this disclosure, the holding time for the second sintering is optionally 2 to 12 hours, optionally 4 to 10 hours, and optionally 6 to 8 hours.

[0111] In order to fully and comprehensively describe the overall technical proposal, and to better ensure the structure and composition of the composite material and the core-shell type glassy solid electrolyte material, and to further improve performance in subsequent applications, the above-mentioned core-shell type glassy solid electrolyte, preparation method and use specifically include the following:

[0112] Preparation of materials: 1. Commercially available LiAlPO4(OH) x F 1-x Using materials and sanding techniques, LiAlPO4(OH) x F 1-x The material is polished into a nano-sized slurry, and then Al(H2PO4)3 adhesive is added and mechanically stirred to form LiAlPO4(OH) x F 1-x To effectively adhere to the surface of the particles.

[0113] Specifically, the amblygonite-based material LiAlPO4(OH) x F 1-x The condition is 0 ≤ x ≤ 1.

[0114] Specifically, the sanding equipment used in sanding techniques is a sand mill.

[0115] Specifically, the polishing media used are deionized water, anhydrous ethanol, and N-methylpyrrolidone (NMP).

[0116] Specifically, the polishing balls used are zirconia balls, with a diameter of 0.05 mm to 0.7 mm.

[0117] Specifically, the polishing rotation speed used is 500 r / min to 2500 r / min, and the polishing time is 2 hours to 10 hours.

[0118] Specifically, the duration of mechanical stirring used ranges from 30 minutes to 600 minutes.

[0119] Specifically, the particle size of the material after stirring is between 80 nm and 600 nm.

[0120] 2. Weigh LiF and AlF3 in a molar ratio of 3:1 and mix them using a planetary ball mill. Dry the resulting slurry in a drying box, then keep the dried powder warm in a muffle furnace for the first sintering, and after the warming is complete, perform a quenching treatment and cool to room temperature to obtain a glassy Li3AlF6 material.

[0121] Specifically, the ratio of ball milling medium to powder used is 3:1.

[0122] Specifically, the ball milling media used are deionized water and anhydrous ethanol.

[0123] Specifically, the material of the abrasive balls used is zirconia.

[0124] Specifically, the diameter of the abrasive ball used is 3 mm.

[0125] Specifically, the ball milling time used is 4 to 12 hours, the rotation speed is 200 r / min to 500 r / min, and the ball-to-material ratio is 10.

[0126] Specifically, the drying temperature used is 80°C to 200°C, and the drying time is 2 to 24 hours.

[0127] Specifically, the temperature for the first sintering is 600°C to 950°C, and the holding time is 5 minutes to 180 minutes.

[0128] Specifically, the hardening methods used are water cooling and cooling with liquid nitrogen.

[0129] 3. The glassy Li3AlF6 material obtained in step 2 is polished, and the powder sieved through a 400-mesh sieve is added to the slurry obtained in step 1 and mechanically stirred for a further 30 to 300 minutes. Then, SiO2 and / or Al2O3 powder is added and mechanically stirred for a further 2 to 24 hours to obtain a mixed slurry.

[0130] 4. The mixed slurry obtained in step 3 is placed in a vacuum sintering furnace and vacuum-dried to obtain a core-shell type glassy solid electrolyte.

[0131] Specifically, the vacuum drying temperature used is 100°C to 300°C, and the drying time is 3 to 48 hours.

[0132] In the core-shell type glassy solid electrolyte relating to this disclosure, the core structure LiAlPO4(OH) x F 1-x It accounts for 30-65 wt.%, with shell structure Al(H2PO4)3 accounting for 0.5-3 wt.%, glassy Li3AlF6 accounting for 5-30 wt.%, and additive SiO2 and / or Al2O3 accounting for 0.03-0.3 wt.%.

[0133] This disclosure further provides lithium-ion battery coated cathode materials.

[0134] Coating of the positive electrode material 1. After polishing the core-shell type glassy solid electrolyte powder obtained in step 4 above, it is sieved through a 400-mesh sieve. A commercially available cathode material is added to a solvent and dispersed by ultrasonic stirring, and the core-shell type glassy solid electrolyte sieved through a 400-mesh sieve is added and mechanically stirred. The uniformly stirred slurry is dried in a forced-air drying box, and the dried powder is sintered in a muffle furnace. After the heating is completed, it is cooled to room temperature to obtain a cathode material coated with a core-shell type glassy solid electrolyte.

[0135] Specifically, the solvents used are anhydrous ethanol and N-methylpyrrolidone (NMP).

[0136] Specifically, the dispersion time using ultrasonic stirring is 20 to 120 minutes, and the mechanical stirring time is 2 to 24 hours.

[0137] Specifically, the drying temperature used is 80°C to 200°C, and the drying time is 2 to 12 hours.

[0138] Specifically, the sintering temperature used is 200°C to 400°C, and the holding time used is 2 to 12 hours.

[0139] Refer to Figure 1, which is a schematic diagram of the core-shell type glassy solid electrolyte according to this disclosure.

[0140] The above-mentioned contents of this disclosure provide composite materials and their uses, core-shell type glassy solid electrolyte materials, methods for preparing and using them, and lithium-ion battery coated cathode materials and methods for preparing them. This disclosure provides a core-shell type glassy fluorine-based solid electrolyte material formed by adding conductive particles with a core-shell structure consisting of an adhesive and a lithium-rich material to glassy β-Li3AlF6 fluoride, and can be used as a cathode coating to achieve several beneficial technical effects. The lithium-containing material used in this disclosure is LiAlPO4(OH) x F 1-xThe material is a polyanionic crystal, exhibiting superior structural stability compared to transition metal oxide materials, superior lithium ion diffusion rate compared to olivine-type materials, and possessing a constant specific capacity. An Al(H2PO4)3 adhesive is used, and the surface of the lithium-containing material is coated with the adhesive to form a core-shell structure. This is then mixed with a glassy Li3AlF6 material to obtain a core-shell type glassy solid electrolyte with relatively good bonding properties.

[0141] LiAlPO4(OH) used in this disclosure x F 1-x It is a good host material for lithium ions, and when used as a coating for the cathode, it assists in the storage of lithium ions in the cathode material, suppresses the decrease in cathode capacity caused by the coating of the solid electrolyte, and allows lithium ions to freely insert and deinsert along the three directions of the a, b, and c axes, has a relatively high lithium ion diffusion coefficient, and has a relatively stable structure.

[0142] This disclosure uses Al(H2PO4)3 as an adhesive and adds a tetrahedral base to Al(H2PO4)3. 3- It is present and contains hydrogen bonds, which provide a strong structure for adhesion between one crystal surface and another, and LiAlPO4(OH) on both sides of the adhesive x F 1-x And Li3AlF6 also has relatively high electronegativity F - Because it has a strong ability to form hydrogen bonds, Al(H2PO4)3 forms hydrogen bonds with LiAlPO4(OH) x F 1-xThe Al(H2PO4)3 adheres firmly to the surface of the glassy Li3AlF6, creating a stable core-shell glassy structure and improving the processability of the solid electrolyte. During the heating process, Al(H2PO4)3 forms an amorphous glassy inlay structure, and hydrogen bonds still exist at this time, maintaining structural stability. During the heating process, Al(H2PO4)3 decomposes to produce Al(PO3)3, and Al(PO3)3 reacts with alkaline lithium, Li2CO3 or LiOH, remaining on the surface of the positive electrode material to produce ionic conductive Li3PO4 and an AlPO4 coating layer that protects the positive electrode. When phosphate root ions become negatively charged and are released into the glassy Li3AlF6 region, they play a role in lithium ion conduction based on the law of charge conservation in the region.

[0143] This disclosure uses Li3AlF6 material as a solid electrolyte, but the Li in the Li3AlF6 crystal structure + Its conductivity is relatively poor, and it has relatively low ionic conductivity. Although amorphization by high-energy ball milling can contribute to improving the lithium ion conductivity of Li3AlF6, the degree of amorphization is incomplete, and the ionic conductivity is relatively large compared to other types of solid electrolytes. This disclosure provides a method for obtaining completely amorphized Li3AlF6 by rapidly cooling using a quenching method, and also provides a lithium diffusion-capable LiAlPO4(OH) x F 1-xBy adding it as a core to constitute a solid electrolyte, the problem of low lithium ion conductivity in the use of Li3AlF6 as a solid electrolyte can be effectively improved. Because glassy materials usually have relatively good flexibility, they can contribute to improving interfacial contact problems between the positive electrode and the electrolyte or electrolyte solution. Therefore, when combined with relatively good ionic conductivity, the interfacial performance of the positive electrode can be effectively improved. Furthermore, Li3AlF6 itself is a relatively stable material and does not react with HF, thus protecting the positive electrode from corrosion by HF and preventing a decrease in positive electrode capacity due to the dissolution of transition metals. In addition, Li3AlF6 has a relatively wide electrochemical window, which can ensure the use of high-voltage positive electrodes.

[0144] By introducing trace amounts of stable glassy compounds such as SiO2 and / or Al2O3 into a core-shell type glassy solid electrolyte, SiO2 can function as a "skeleton" for the glassy material, suppressing the tendency for the glassy material to crystallize during the sintering process in the cathode coating process, thereby improving the chemical and thermal stability of the glassy material. On the other hand, SiO2 and / or Al2O3 can improve the thermal stability of Al(H2PO4)3.

[0145] The core-shell type glassy solid electrolyte according to this disclosure can be used as a coating for the positive electrode, suppressing the side effects of the solid electrolyte on the capacity of the positive electrode, effectively solving the problem of lithium remaining on the surface during the preparation process of the positive electrode material, effectively improving the surface performance of the positive electrode material, protecting the positive electrode material from the effects of HF, suppressing the dissolution of transition metals in the positive electrode material, and ensuring that the positive electrode exhibits relatively good electrochemical performance.

[0146] To further illustrate this disclosure, the following examples will describe in detail the composite materials and their uses relating to this disclosure, the core-shell type glassy solid electrolyte materials and their preparation methods and uses, and the lithium-ion battery coated cathode materials and their preparation methods. These examples were carried out based on the technical proposals of this disclosure, and detailed embodiments and specific operating procedures have been described to further illustrate the features and advantages of this disclosure, but this is not intended to limit the scope of the claims of this disclosure, and the scope of protection of this disclosure is not limited to the following examples.

[0147] Example 1 Add 800g of deionized water as a solvent to the sand mill, and add commercially available LiAlPO4(OH) 0.5 F 0.5 200g was weighed and added, and sanding was performed. The sanding balls used in the sand mill were zirconia balls with a diameter of 0.3mm, the sand mill was set to a rotation speed of 500 r / min, and the sanding time was 10 hours. The slurry was then placed in a beaker and mechanically stirred for 20 minutes, after which 3.34g of Al(H2PO4)3 was added and stirred for a further 600 minutes to obtain a slurry of lithium-containing material having a core-shell structure, and the particle size of the obtained composite material was 600nm.

[0148] 24.05 g of LiF and 25.95 g of AlF were weighed and mixed in a planetary ball mill. 150 g of deionized water was added as the solvent during mixing. 3 mm zirconia balls were used for ball milling. The mass of polished balls was 500 g. The ball milling time was 4 hours, and the ball milling speed was 500 r / min. The slurry after ball milling was dried in a drying chamber at 200°C for 2 hours to obtain a precursor. After polishing the precursor, it was placed in a covered crucible and sintered in a muffle furnace at a sintering temperature of 600°C for 180 minutes. After the heating was complete, the crucible was removed while still hot, and quenched with a cold water shower. After cooling to room temperature, a glassy Li3AlF6 material was obtained, with a particle size of 400 nm for the Li3AlF6 powder.

[0149] After polishing the glassy Li3AlF6 material prepared in multiple batches, it was sieved through a 400-mesh sieve, and 33.3 g of powder was taken and added to a slurry of lithium-containing material having a core-shell structure obtained by stirring, which was stirred for a further 30 minutes. Then, 0.2 g of SiO2 was added and stirred for a further 2 hours to obtain a mixed slurry.

[0150] The mixed slurry was dried in a vacuum drying chamber to obtain a core-shell type glassy solid electrolyte. The core-shell type glassy solid electrolyte had a powder particle size D50 of 1.0 μm and a shell layer thickness of 50 nm. A vacuum environment was continuously maintained during the drying process, the drying temperature was 100°C, and the drying time was 48 hours.

[0151] After polishing the prepared core-shell type glassy solid electrolyte powder, it was sieved through a 400-mesh sieve. 18 g of commercially available LiCoO2 was added to 120 ml of anhydrous ethanol and ultrasonically dispersed for 20 minutes. Then, 0.36 g of the prepared solid electrolyte was added and mechanically stirred for 24 hours. The uniformly stirred slurry was dried in a forced-air drying chamber at a temperature of 80°C for 12 hours. The dried powder was then sintered in a muffle furnace to obtain a cathode material coated with a core-shell type glassy solid electrolyte. The thickness of the coating layer was 1.2 μm, the sintering temperature used was 200°C, and the holding time was 12 hours.

[0152] Refer to Figure 2, which is an SEM image of the core-shell type glassy solid electrolyte prepared in Example 1 of this disclosure.

[0153] Example 2 Add 750g of deionized water as a solvent to the sand mill, and add commercially available LiAlPO4(OH) 0.3 F 0.7250g was weighed and added, and sanding was performed. The sanding ball used in the sand mill was a zirconia ball with a diameter of 0.1mm, the sand mill was set to a rotation speed of 2500 r / min, and the sanding time was 2 hours. The slurry was then placed in a beaker and mechanically stirred for 40 minutes, after which 11.54g of Al(H2PO4)3 was added and stirred for a further 30 minutes to obtain a slurry of lithium-containing material having a core-shell structure. The resulting composite material had a particle size of 80nm.

[0154] 26.45g of LiF and 25.95g of AlF were weighed and mixed in a planetary ball mill. 150g of deionized water was added as the solvent during mixing. 3mm zirconia balls were used for ball milling. The mass of polished balls was 500g. The ball milling time was 12 hours, and the ball milling speed was 200 r / min. The slurry after ball milling was dried in a drying chamber at 80°C for 24 hours to obtain a precursor. After polishing the precursor, it was placed in a covered crucible and sintered in a muffle furnace at a sintering temperature of 950°C for 5 minutes. After the heating was complete, the crucible was removed while still hot, and liquid nitrogen was sprayed to perform quenching. After cooling to room temperature, a glassy Li3AlF6 material was obtained, with a particle size of 100nm of Li3AlF6 powder.

[0155] After polishing the glassy Li3AlF6 material prepared in multiple batches, it was sieved through a 400-mesh sieve, and 115.38 g of powder was taken and added to a slurry of lithium-containing material having a core-shell structure obtained by stirring, and stirred for a further 300 minutes. Then, 1.15 g of SiO2 was added and stirred for a further 24 hours to obtain a mixed slurry.

[0156] The mixed slurry was dried in a vacuum drying chamber to obtain a core-shell type glassy solid electrolyte. The core-shell type glassy solid electrolyte had a powder particle size D50 of 0.4 μm and a shell layer thickness of 10 nm. A vacuum environment was continuously maintained during the drying process, the drying temperature was 300°C, and the drying time was 3 hours.

[0157] After polishing the prepared core-shell type glassy solid electrolyte powder, it was sieved through a 400-mesh sieve. 19.5 g of commercially available LiCoO2 was added to 120 ml of NMP and ultrasonically dispersed for 120 minutes. Then, 2.9 g of the prepared solid electrolyte was added and mechanically stirred for 2 hours. The uniformly stirred slurry was dried in a forced-air drying chamber at a temperature of 200°C for 2 hours. The dried powder was then sintered in a muffle furnace to obtain a cathode material coated with a core-shell type glassy solid electrolyte. The thickness of the coating layer was 0.4 μm, the sintering temperature used was 400°C, and the holding time was 2 hours.

[0158] Example 3 800g of anhydrous ethanol was added as a solvent to a sand mill, and 200g of commercially available LiAlPO4(OH) was weighed and added to perform sanding. The sanding ball used in the sand mill was a zirconia ball with a diameter of 0.05mm, the sand mill was set to a rotation speed of 2000 r / min, and the polishing time was 5 hours. The slurry was then placed in a beaker and mechanically stirred for 20 minutes, after which 20g of Al(H2PO4)3 was added and stirred for a further 500 minutes to obtain a slurry of lithium-containing material having a core-shell structure, and the particle size of the obtained composite material was 400nm.

[0159] 24.85g of LiF and 25.95g of AlF were weighed and mixed in a planetary ball mill. 150g of anhydrous ethanol was added as the solvent during mixing. 3mm zirconia balls were used for ball milling. The mass of polished balls was 500g. The ball milling time was 6 hours, and the ball milling speed was 350 r / min. The slurry after ball milling was dried in a drying chamber at 100°C for 12 hours to obtain a precursor. After polishing the precursor, it was placed in a covered crucible and sintered in a muffle furnace at a sintering temperature of 700°C for 20 minutes. After the heating was complete, the crucible was removed while still hot, and liquid nitrogen was sprayed to perform quenching. After cooling to room temperature, a glassy Li3AlF6 material was obtained, with a particle size of 100nm of Li3AlF6 powder.

[0160] After polishing the glassy Li3AlF6 material prepared in multiple batches, it was sieved through a 400-mesh sieve, 100g of the powder was taken and added to a slurry of lithium-containing material having a core-shell structure obtained by stirring, and stirred for a further 20 minutes. Then, 1.0g of SiO2 was added and stirred for a further 12 hours to obtain a mixed slurry.

[0161] The mixed slurry was dried in a vacuum drying chamber to obtain a core-shell type glassy solid electrolyte. The core-shell type glassy solid electrolyte had a powder particle size D50 of 0.6 μm and a shell layer thickness of 20 nm. A vacuum environment was continuously maintained during the drying process, the drying temperature was 200°C, and the drying time was 24 hours.

[0162] After polishing the prepared core-shell type glassy solid electrolyte powder, it was sieved through a 400-mesh sieve. 19.3 g of commercially available LiCoO2 was added to 120 ml of anhydrous ethanol and ultrasonically dispersed for 40 minutes. Then, 0.97 g of the prepared solid electrolyte was added and mechanically stirred for 12 hours. The uniformly stirred slurry was dried in a forced-air drying chamber at 100°C for 10 hours. The dried powder was then sintered in a muffle furnace to obtain a cathode material coated with a core-shell type glassy solid electrolyte. The coating layer thickness was 0.8 μm, the sintering temperature used was 300°C, and the holding time was 10 hours.

[0163] Example 4 850 g of NMP was added as a solvent to a sand mill, and 150 g of commercially available LiAlPO4F was weighed and added to perform sanding. The sanding ball used in the sand mill was a zirconia ball with a diameter of 0.7 mm, the sand mill was set to a rotation speed of 600 r / min, and the polishing time was 9 hours. The slurry was then placed in a beaker and mechanically stirred for 20 minutes, after which 2.0 g of Al(H2PO4)3 was added and stirred for a further 600 minutes to obtain a slurry of lithium-containing material having a core-shell structure, and the particle size of the obtained composite material was 500 nm.

[0164] 24.05g of LiF and 25.95g of AlF were weighed and mixed in a planetary ball mill. 150g of anhydrous ethanol was added as the solvent during mixing. 3mm zirconia balls were used for ball milling. The mass of polished balls added was 500g. The ball milling time was 8 hours, and the ball milling rotation speed was 450 r / min. The slurry after ball milling was dried in a drying box at 120°C for 8 hours to obtain a precursor. After polishing the precursor, it was placed in a covered crucible and sintered in a muffle furnace at a sintering temperature of 900°C for a holding time of 10 minutes. After the holding time, the crucible was removed while still hot, and quenched with a cold water shower. After cooling to room temperature, a glassy Li3AlF6 material was obtained, with a particle size of 150nm of Li3AlF6 powder.

[0165] After polishing the glassy Li3AlF6 material prepared in multiple batches, it was sieved through a 400-mesh sieve, 60 g of the powder was taken and added to a slurry of lithium-containing material having a core-shell structure obtained by stirring, and stirred for a further 30 minutes. Then, 0.6 g of Al2O3 was added and stirred for a further 24 hours to obtain a mixed slurry.

[0166] The mixed slurry was dried in a vacuum drying chamber to obtain a core-shell type glassy solid electrolyte. The core-shell type glassy solid electrolyte had a powder particle size D50 of 0.9 μm and a shell layer thickness of 30 nm. A vacuum environment was continuously maintained during the drying process, the drying temperature was 100°C, and the drying time was 48 hours.

[0167] After polishing the prepared core-shell type glassy solid electrolyte powder, it was sieved through a 400-mesh sieve. 18.4 g of commercially available LiCoO2 was added to 120 ml of anhydrous ethanol and ultrasonically dispersed for 35 minutes. Then, 1.84 g of the prepared solid electrolyte was added and mechanically stirred for 12 hours. The uniformly stirred slurry was dried in a forced-air drying chamber at a temperature of 150°C for 10 hours. The dried powder was then sintered in a muffle furnace to obtain a cathode material coated with a core-shell type glassy solid electrolyte. The thickness of the coating layer was 1.0 μm, the sintering temperature used was 250°C, and the holding time was 10 hours.

[0168] Example 5 Add 700g of NMP as a solvent to the sand mill, and add commercially available LiAlPO4(OH) 0.2 F 0.8 300g was weighed and added, and sanding was performed. The sanding balls used in the sand mill were zirconia balls with a diameter of 0.5mm, the sand mill was set to a rotation speed of 1500 r / min, and the sanding time was 7 hours. The slurry was then placed in a beaker and mechanically stirred for 30 minutes, after which 10g of Al(H2PO4)3 was added and stirred for a further 400 minutes to obtain a slurry of lithium-containing material having a core-shell structure. The particle size of the resulting composite material was 200nm.

[0169] 24.05 g of LiF and 25.95 g of AlF were weighed and mixed in a planetary ball mill. 150 g of anhydrous ethanol was added as the solvent during mixing. 3 mm zirconia balls were used for ball milling. The mass of polished balls was 500 g. The ball milling time was 6 hours, and the ball milling rotation speed was 500 r / min. The slurry after ball milling was dried in a drying box at 180°C for 6 hours to obtain a precursor. After polishing the precursor, it was placed in a covered crucible and sintered in a muffle furnace at a sintering temperature of 800°C for 30 minutes. After the heating was complete, the crucible was removed while still hot, and quenched with a cold water shower. After cooling to room temperature, a glassy Li3AlF6 material was obtained, with a particle size of 350 nm for the Li3AlF6 powder.

[0170] After polishing the glassy Li3AlF6 material prepared in multiple batches, it was sieved through a 400-mesh sieve, 100g of the powder was taken and added to a slurry of lithium-containing material having a core-shell structure obtained by stirring, and stirred for a further 60 minutes. Then, 0.5g of SiO2 and 0.5g of Al2O3 were added and stirred for a further 24 hours to obtain a mixed slurry.

[0171] The mixed slurry was dried in a vacuum drying chamber to obtain a core-shell type glassy solid electrolyte. The core-shell type glassy solid electrolyte had a powder particle size D50 of 0.8 μm and a shell layer thickness of 30 nm. A vacuum environment was continuously maintained during the drying process, the drying temperature was 200°C, and the drying time was 24 hours.

[0172] After polishing the prepared core-shell type glassy solid electrolyte powder, it was sieved through a 400-mesh sieve. 18.5 g of commercially available LiCoO2 was added to 120 ml of NMP and ultrasonically dispersed for 60 minutes. Then, 1.5 g of the prepared solid electrolyte was added and mechanically stirred for 12 hours. The uniformly stirred slurry was dried in a forced-air drying chamber at 120°C for 8 hours. The dried powder was then sintered in a muffle furnace to obtain a cathode material coated with a core-shell type glassy solid electrolyte. The coating layer thickness was 1.0 μm, the sintering temperature used was 200°C, and the holding time was 10 hours.

[0173] Example 6 Add 800g of NMP as a solvent to the sand mill, and add commercially available LiAlPO4(OH) 0.8 F 0.2 200g was weighed and added, and sanding was performed. The sanding balls used in the sand mill were zirconia balls with a diameter of 0.7mm, the sand mill was set to a rotation speed of 600 r / min, and the sanding time was 9 hours. The slurry was then placed in a beaker and mechanically stirred for 20 minutes, after which 0.8g of Al(H2PO4)3 was added and stirred for a further 600 minutes to obtain a slurry of lithium-containing material having a core-shell structure. The particle size of the obtained composite material was 550nm.

[0174] 24.05 g of LiF and 25.95 g of AlF were weighed and mixed in a planetary ball mill. 150 g of anhydrous ethanol was added as the solvent during mixing. 3 mm zirconia balls were used for ball milling. The mass of polished balls was 500 g. The ball milling time was 8 hours, and the ball milling rotation speed was 450 r / min. The slurry after ball milling was dried in a drying box at 120°C for 8 hours to obtain a precursor. After polishing the precursor, it was placed in a covered crucible and sintered in a muffle furnace at a sintering temperature of 700°C for a holding time of 120 minutes. After the holding time, the crucible was removed while still hot, and quenched with a cold water shower. After cooling to room temperature, a glassy Li3AlF6 material was obtained, with a particle size of 350 nm for the Li3AlF6 powder.

[0175] After polishing the glassy Li3AlF6 material prepared in multiple batches, it was sieved through a 400-mesh sieve, 50 g of the powder was taken and added to a slurry of lithium-containing material having a core-shell structure obtained by stirring, and stirred for a further 30 minutes. Then, 0.25 g of Al2O3 was added and stirred for a further 24 hours to obtain a mixed slurry.

[0176] The mixed slurry was defluorinated by vacuum drying in a vacuum drying chamber to obtain a core-shell type glassy solid electrolyte. The core-shell type glassy solid electrolyte had a powder particle size D50 of 1.1 μm and a shell layer thickness of 30 nm. A vacuum environment was continuously maintained during the drying process, the drying temperature was 100°C, and the drying time was 48 hours.

[0177] After polishing the prepared core-shell type glassy solid electrolyte powder, it was sieved through a 400-mesh sieve. 18.4 g of commercially available LiCoO2 was added to 120 ml of NMP and ultrasonically dispersed for 340 minutes. Then, 1.5 g of the prepared solid electrolyte was added and mechanically stirred for 12 hours. The uniformly stirred slurry was dried in a forced-air drying chamber at a temperature of 150°C for 10 hours. The dried powder was then sintered in a muffle furnace to obtain a cathode material coated with a core-shell type glassy solid electrolyte. The thickness of the coating layer was 1.2 μm, the sintering temperature used was 400°C, and the holding time was 10 hours.

[0178] Example 7 Add 850g of NMP as a solvent to the sand mill, and add commercially available LiAlPO4(OH) 0.5 F 0.5 325g was weighed and added, and sanding was performed. The sanding balls used in the sand mill were zirconia balls with a diameter of 0.7mm, the sand mill was set to a rotation speed of 2500 r / min, and the sanding time was 6 hours. The slurry was then placed in a beaker and mechanically stirred for 30 minutes, after which 20g of Al(H2PO4)3 was added and stirred for a further 600 minutes to obtain a slurry of lithium-containing material having a core-shell structure, and the particle size of the obtained composite material was 200nm.

[0179] 24.05 g of LiF and 25.95 g of AlF were weighed and mixed in a planetary ball mill. 150 g of anhydrous ethanol was added as the solvent during mixing. 3 mm zirconia balls were used for ball milling. The mass of polished balls was 500 g. The ball milling time was 8 hours, and the ball milling speed was 450 r / min. The slurry after ball milling was dried in a drying box at 120°C for 8 hours to obtain a precursor. After polishing the precursor, it was placed in a covered crucible and sintered in a muffle furnace at a sintering temperature of 900°C for 60 minutes. After the heating was complete, the crucible was removed while still hot and quenched with a cold water shower. After cooling to room temperature, a glassy Li3AlF6 material was obtained, with a particle size of 150 nm for the Li3AlF6 powder.

[0180] After polishing the glassy Li3AlF6 material prepared in multiple batches, it was sieved through a 400-mesh sieve, and 80 g of powder was taken and added to a slurry of lithium-containing material having a core-shell structure obtained by stirring, which was stirred for a further 30 minutes. Then, 0.4 g of Al2O3 was added and stirred for a further 24 hours to obtain a mixed slurry.

[0181] The mixed slurry was vacuum-dried in a vacuum drying chamber to obtain a core-shell type glassy solid electrolyte. The core-shell type glassy solid electrolyte had a powder particle size D50 of 0.5 μm and a shell layer thickness of 50 nm. A vacuum environment was continuously maintained during the drying process, the drying temperature was 100°C, and the drying time was 48 hours.

[0182] After polishing the prepared core-shell type glassy solid electrolyte powder, it was sieved through a 400-mesh sieve. 18.4 g of commercially available LiCoO2 was added to 120 ml of anhydrous ethanol and ultrasonically dispersed for 35 minutes. Then, 1.84 g of the prepared solid electrolyte was added and mechanically stirred for 12 hours. The uniformly stirred slurry was dried in a forced-air drying chamber at a temperature of 150°C for 10 hours. The dried powder was then sintered in a muffle furnace to obtain a cathode material coated with a core-shell type glassy solid electrolyte. The thickness of the coating layer was 0.7 μm, the sintering temperature used was 400°C, and the holding time was 10 hours.

[0183] Comparative Example 1 A solid electrolyte was prepared according to the method of Example 1, but LiAlPO4(OH) 0.5 F 0.5 No "shell" structure Al(H2PO4)3 material was added to the nano-sized slurry. Therefore, the prepared solid electrolyte was LiAlPO4(OH) 0.5 F 0.5 -A glassy Li3AlF6 solid electrolyte was used, and the LiCoO2 cathode was coated with it according to the method of Example 1.

[0184] Comparative Example 2 A solid electrolyte was prepared by referring to the method of Example 1, but during the preparation process of the Li3AlF6 solid electrolyte, furnace cooling was performed to obtain a core-shell structure Li3AlF6 solid electrolyte made of Li3AlF6 material with good crystallinity, and then the LiCoO2 cathode was coated by referring to the method of Example 1.

[0185] Comparative Example 3 A solid electrolyte was prepared according to the method of Example 1, but without adding the additive SiO2 and / or Al2O3 to the solid electrolyte slurry formed by mixing, and the LiCoO2 cathode was coated according to the method of Example 1.

[0186] Comparative Example 4 A glassy Li3AlF6 solid electrolyte was prepared using the method of Example 1, and then the LiCoO2 cathode was coated with only the glassy Li3AlF6, referring to the method of Example 1.

[0187] Comparative Example 5 Using the same uncoated positive electrode material LiCoO2 as in Example 6, a coin-type battery was prepared and measured directly using the measurement method according to this application.

[0188] Comparative Example 6 A commercially available AlPO4 material was used to coat the LiCoO2 cathode material according to the coating method described in Example 6.

[0189] Experimental example The coated positive electrode obtained through the above preparation was used as the active material for the lithium-ion battery positive electrode material in the preparation of a lithium-ion battery. Specifically, the prepared lithium-ion battery positive electrode material active material, conductive carbon black, and polyvinylidene fluoride were mixed in a mass ratio of 8:1:1, a certain amount of N-methylpyrrolidone was added and mixed uniformly to form a slurry, and the slurry was uniformly applied to aluminum foil, dried, and punched out into 12 mm electrode plates. The electrode plates were dried in a vacuum drying box at 120°C for 12 hours and stored in a glove box. A coin-type battery was assembled using the electrode plate as the positive electrode and a metallic lithium piece as the negative electrode, with an electrolyte prepared by mixing 1 M LiPF6 with ethylene carbonate (EC) / dimethyl carbonate (DMC) (v:v=1:1), and polypropylene (PP) as the separator. For the assembled coin-type batteries, electrochemical performance was measured at 25°C within a range of 3 to 4.6V. The initial discharge ratio capacity was measured at a rate of 0.1C, the capacity retention rate after 100 cycles was measured at a rate of 0.5C, and the rate performance was measured by constant current charge and discharge at 0.5C and 5C.

[0190] Refer to Table 1, which shows the results of electrochemical measurements of the examples and comparative examples of this disclosure.

[0191] [Table 1]

[0192] The above describes in detail the composite materials and their uses, core-shell glassy solid electrolyte materials, methods for preparing and using them, and lithium-ion battery coated cathode materials and methods for preparing them. This specification uses specific examples to illustrate the principles and embodiments of the disclosure. The above description of the examples is intended to facilitate understanding of the methods and core ideas of the disclosure, including the most preferred embodiments. It also includes the manufacture and use of any device or system, and any combination methods, to enable those skilled in the art to practice the disclosure. Those skilled in the art can make several improvements and modifications to the disclosure, provided they do not deviate from the principles of the disclosure, and these improvements and modifications are also included in the claims of the disclosure. The scope of protection of the disclosure is limited by the claims and includes other embodiments that a person skilled in the art may conceive. If these other embodiments have structural elements similar to, or equivalent structural elements that are substantially indistinguishable from, those other embodiments should also be considered included in the claims. Industrial applicability This disclosure provides composite materials and their uses, core-shell type glassy solid electrolyte materials and methods for preparing and using them, and lithium-ion battery coated cathode materials and methods for preparing them. The core-shell type glassy solid electrolyte materials according to this disclosure can effectively improve the surface performance of cathode materials, protect cathode materials from the effects of HF, suppress the dissolution of transition metals in cathode materials, and ensure that cathodes exhibit relatively good electrochemical performance. Furthermore, the preparation method is simple and easy to implement, the conditions are mild, it is highly controllable, it has excellent stability, and it is easier to disseminate into mass production and use.

Claims

1. It is a composite material, LiAlPO ４ (OH) ｘ F １－ｘ and LiAlPO ４ (OH) ｘ F １－ｘ composite Al(H ２ PO ４ ) ３ and include Here, x satisfies 0 ≤ x ≤ 1. A composite material characterized by the following features.

2. The composite material has a core-shell structure, The LiAlPO ４ (OH) ｘ F １－ｘ The core is the Al(H ２ PO ４ ) ３ It is a shell layer, The Al(H) shell layer ２ PO ４ ) ３ The thickness is 10 nm to 50 nm. The particle size of the composite material is 80 nm to 600 nm. The LiAlPO ４ (OH) ｘ F １－ｘ and the aforementioned Al(H ２ PO ４ ) ３ The mass ratio is (30-65):(0.5-3). The composite material according to feature 1.

3. Use of the composite material according to claim 1 or 2 in a solid electrolyte material or lithium-ion battery.

4. The solid electrolyte material includes a fluorine-based solid electrolyte material. The fluorine-based solid electrolyte material includes a glassy fluorine-based solid electrolyte material. The glassy fluorine-based solid electrolyte material is Li ３ AlF ６ including The use described in claim 3.

5. A core-shell type glassy solid electrolyte material, As a raw material, Li ３ AlF ６ And, Li ３ AlF ６ It includes composite materials that are compounded with The composite material includes the composite material described in claim 1 or 2. A core-shell type glassy solid electrolyte material characterized by the following features.

6. Li in the core-shell type glassy solid electrolyte material ３ AlF ６ It is the base material, Li ３ AlF ６ The composite material, specifically, is composed of Li ３ AlF ６ It is a composite material in which the particles are dispersed. The Li ３ AlF ６ and LiAlPO in the composite material ４ (OH) ｘ F １－ｘ The mass ratio is (5-30):(30-65), The core-shell type glassy solid electrolyte material includes a core-shell type glassy solid electrolyte material used in lithium-ion batteries. The core-shell type glassy solid electrolyte material according to feature 5.

7. The aforementioned raw materials are SiO ２ or / and Al ２ O ３ It further includes, The SiO ２ or / and Al ２ O ３ The Li ３ AlF ６ It is distributed across, The SiO ２ or / and Al ２ O ３ and the Li ３ AlF ６ The mass ratio is (0.03–0.3):(5–30), The lithium-ion battery includes a coating material for the lithium-ion battery cathode material. The core-shell type glassy solid electrolyte material according to claim 5 or 6.

8. A method for preparing a core-shell type glassy solid electrolyte material according to any one of claims 5 to 7, LiAlPO ４ (OH) ｘ F １－ｘ Slurry and Al(H) ２ PO ４ ) ３ Mixing these together yields a slurry where x satisfies 0 ≤ x ≤ 1, and LiF and AlF ３ After pre-mixing, the first sintering is performed to produce glassy Li. ３ AlF ６ Obtain the material, and then polish it to create glassy Li ３ AlF ６ Step (1) to obtain the powder, The glassy Li obtained in step (1) ３ AlF ６ Powder, SiO ２ or / and Al ２ O ３ The process includes step (2) of mixing the powder with the slurry a second time to obtain a mixed slurry, and then vacuum drying to obtain the core-shell type glassy solid electrolyte material. A method for preparing a core-shell type glassy solid electrolyte material, characterized by the features described herein.

9. The LiAlPO ４ (OH) ｘ F １－ｘ Slurry is LiAlPO ４ (OH) ｘ F １－ｘ This was obtained by polishing the material. The aforementioned polishing method includes wet polishing. The rotational speed of the polishing is 500 r / min to 2500 r / min. The polishing time is between 2 and 10 hours. The preparation method according to feature 8.

10. The mixing time is between 30 minutes and 600 minutes. The LiF and the AlF ３ The molar ratio is (3.0-3.3):

1. The aforementioned premixing method includes mixing by planetary ball milling, The premixing time is 4 to 12 hours. The rotational speed for the premixing is 200 r / min to 500 r / min. The preparation method according to 8 or 9, characterized by the features described above.

11. The process further includes a drying step after the aforementioned premixing, The drying temperature is 80°C to 200°C. The drying time is between 2 and 24 hours. The temperature of the first sintering was 600°C to 950°C. The duration of the first sintering process is between 5 and 180 minutes. The preparation method according to any one of claims 8 to 10.

12. The process further includes a quenching step after the first sintering, The aforementioned quenching method includes water quenching or cooling with liquid nitrogen. The glassy Li ３ AlF ６ The particle size of the powder is between 100 nm and 400 nm. The preparation method according to any one of claims 8 to 11.

13. The second mixing described above specifically involves the glassy Li ３ AlF ６ The powder and the slurry are mixed first, and then the SiO ２ or / and Al ２ O ３ Further mix with the powder, The initial mixing time is 30 to 300 minutes. Furthermore, the mixing time is 2 to 24 hours. The vacuum drying temperature is 100°C to 300°C. The vacuum drying time is between 3 and 48 hours. The preparation method according to any one of claims 8 to 12.

14. Use of a core-shell type glassy solid electrolyte material according to any one of claims 5 to 7 or a core-shell type glassy solid electrolyte material prepared by the preparation method according to any one of claims 8 to 13 in a lithium-ion battery.

15. The lithium-ion battery specifically includes a lithium-ion battery cathode material, The aforementioned use is specifically in coating materials for lithium-ion battery cathode materials. The use described in feature 14.

16. A lithium-ion battery coated positive electrode material, It comprises a positive electrode material and a core-shell type glassy solid electrolyte material coated with the positive electrode material. The core-shell type glassy solid electrolyte material includes the core-shell type glassy solid electrolyte material described in any one of claims 5 to 7 or the core-shell type glassy solid electrolyte material prepared by the preparation method described in any one of claims 8 to 13. A lithium-ion battery coated positive electrode material characterized by the following features.

17. The mass ratio of the positive electrode material to the core-shell type glassy solid electrolyte material is 1:(0.02 to 0.15). The thickness of the coating layer of the core-shell type glassy solid electrolyte material is 0.6 μm to 1.2 μm. The lithium-ion battery coated positive electrode material according to claim 16.

18. The process includes the steps of mixing a positive electrode material, a polished core-shell type glassy solid electrolyte material, and a solvent, followed by a second sintering to obtain a coated positive electrode material coated with a core-shell type glassy solid electrolyte, The core-shell type glassy solid electrolyte material includes the core-shell type glassy solid electrolyte material described in any one of claims 5 to 7 or the core-shell type glassy solid electrolyte material prepared by the preparation method described in any one of claims 8 to 13. A method for preparing a lithium-ion battery coated positive electrode material, characterized by the features described herein.

19. The powder particle size D50 of the core-shell type glassy solid electrolyte material after polishing is 0.4 μm to 1.0 μm. The specific steps of the mixing are as follows: First, the positive electrode material and the solvent are dispersed by ultrasonic stirring, and then the polished core-shell type glassy solid electrolyte material is added and stirred and mixed. The solvent is anhydrous ethanol and / or N-methylpyrrolidone. The dispersion time by ultrasonic stirring is 20 minutes to 120 minutes. The stirring and mixing time is 2 to 24 hours. The preparation method according to feature 18.

20. The process further includes a drying step after the mixing, The drying temperature is 80°C to 200°C. The drying time is between 2 and 12 hours. The temperature for the second sintering was 200°C to 400°C. The holding time for the second sintering is 2 to 12 hours. The preparation method according to claim 18 or 19, characterized by the features described above.

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