Solid electrolyte materials and preparation, lithium-ion solid-state batteries and applications

Abstract

The present invention provides a solid electrolyte material and preparation thereof, a lithium ion solid-state battery and application thereof, wherein the solid electrolyte material comprises a base material and a coating layer coated on the outer surface of the base material; wherein the structural formula of the base material is Li 1+x Al x Ti 2‑x (PO4)3, 0.1≤x≤0.5; the material of the coating layer is ZnZr4(PO4)6. The solid electrolyte material has high ion conductivity and density, and the ternary positive electrode material coated by it also shows excellent thermal stability.

Description

Technical Field

[0001] The present invention relates to the field of lithium-ion batteries, and in particular to a solid electrolyte material and preparation thereof, a lithium-ion solid-state battery and application thereof. Background Art

[0002] Liquid electrolytes in traditional lithium-ion batteries have problems such as poor cycle performance and potential safety hazards, while solid electrolytes are safer and more stable, can continue to work normally over a wide temperature range, and have broad application prospects in power and energy storage. Therefore, more and more researchers are committed to the technical methods of replacing liquid electrolytes with solid electrolytes, and are beginning to focus on the development and application of all-solid-state lithium-ion batteries.

[0003] Lithium Aluminum Titanium Phosphate (Li 1+x Al x Ti 2-x (PO4)3, LATP) solid electrolyte, because of its high ionic conductivity has received widespread attention. At present, the most commonly used methods for preparing LATP solid electrolyte are sol-gel method, molten salt quenching method, hydrothermal method and high-temperature solid phase method. Among them, Al2O3 is generally used as the aluminum source in the solid phase method; and in the preparation methods involving solutions such as sol-gel or hydrothermal method, aluminum nitrate is generally used as the aluminum source. The ionic conductivity of the ceramic body sintered by LATP powder prepared by the sol-gel method can reach 10 -4 S / cm, the nano-LATP obtained by high-energy ball milling solid phase method can also reach 10 after heat treatment. -4 S / cm.

[0004] Solid electrolytes usually rely mainly on the migration of conductive ions to achieve their conductive function. The faster the ion migration rate, the better the conductivity of the electrolyte. The ion migration rate is closely related to the compactness of the crystal arrangement inside the lithium ion conductor. However, the above-mentioned LATP materials all have the problem of poor compactness, which leads to low ion conductivity, thus affecting the electrochemical performance of the battery. Based on this, there is an urgent need to provide a new solid electrolyte material to solve the problem of low ion conductivity of lithium aluminum titanium phosphate materials in the prior art. Summary of the invention

[0005] The main purpose of the present invention is to provide a solid electrolyte material and preparation, a lithium ion solid-state battery and application, so as to solve the problems of low ion conductivity of lithium aluminum titanium phosphate materials in the prior art.

[0006] In order to achieve the above object, according to one aspect of the present invention, a solid electrolyte material is provided, which comprises a matrix material and a coating layer coated on the outer surface of the matrix material; wherein the structural formula of the matrix material is Li 1+x Al x Ti 2-x (PO4)3, 0.1≤x≤0.5; the material of the coating layer is ZnZr4(PO4)6.

[0007] Furthermore, in the structural formula of the matrix material, 0.2≤x≤0.4; preferably, the ZnZr4(PO4)6 in the coating layer and the Li 1+x Al x Ti 2-x The molar ratio of (PO4)3 is (0.001~0.02):1.

[0008] Furthermore, the density of the solid electrolyte material is 95-98%.

[0009] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a method for preparing a solid electrolyte material is provided, and the preparation method comprises the following steps: step S1, performing a first calcination on a first dispersion containing a zinc source, a zirconium source and a first phosphate source to obtain ZnZr4(PO4)6; step S2, mixing a second dispersion containing a lithium source, an aluminum source, a titanium source and a second phosphate source with ZnZr4(PO4)6 and performing a second calcination to obtain a solid electrolyte material.

[0010] Furthermore, the pH value of the first dispersion is 8 to 10; preferably, the dispersant of the first dispersion is one or more of anhydrous ethanol, anhydrous methanol or ethyl acetate; preferably, the zinc source is selected from one or more of zinc sulfide, zinc carbonate or zinc chloride; preferably, the zirconium source is selected from one or more of zirconium oxychloride, zirconium hydroxide or zirconium chloride; preferably, the first phosphate source is selected from one or more of ammonium dihydrogen phosphate, phosphoric acid or diammonium hydrogen phosphate.

[0011] Furthermore, before the first calcination, the preparation method of the solid electrolyte material also includes the steps of performing a first ball milling and a first drying on the first dispersion in sequence; preferably, the processing speed of the first ball milling is 150-400 rpm, and the processing time is 2-5 hours; preferably, the processing temperature of the first drying is 90-110°C, and the processing time is 1-4 hours; preferably, the processing temperature of the first calcination is 300-700°C, and the processing time is 6-12 hours.

[0012] Furthermore, the dispersant of the second dispersion is one or more of anhydrous ethanol, anhydrous methanol or ethyl acetate; preferably, the molar ratio of ZnZr4(PO4)6 to the second phosphate source is (0.001-0.02):3; preferably, the lithium source is selected from one or more of lithium carbonate, lithium hydroxide or lithium oxide; preferably, the aluminum source is selected from one or more of aluminum oxide, aluminum hydroxide or aluminum chloride; preferably, the titanium source is selected from one or more of titanium oxide, titanium chloride or titanium hydroxide; preferably, the second phosphate source is selected from one or more of diammonium phosphate, phosphoric acid or diammonium hydrogen phosphate.

[0013] Furthermore, before the second calcination, the preparation method of the solid electrolyte material also includes the steps of sequentially performing second ball milling and second drying on the second dispersion; the processing speed of the second ball milling is 200-500 rpm, and the processing time is 2-10 hours; the processing temperature of the second drying is 60-100°C, and the processing time is 4-8 hours; the processing temperature of the second calcination is 850-950°C, and the processing time is 8-12 hours.

[0014] According to another aspect of the present invention, a lithium-ion solid-state battery is provided, which includes the above-mentioned solid-state electrolyte material, or the solid-state electrolyte material prepared by the above-mentioned method for preparing the solid-state electrolyte material.

[0015] According to another aspect of the present invention, there is provided an application of a lithium ion solid-state battery, wherein the lithium ion solid-state battery is applied in an electric vehicle or an electric bicycle.

[0016] The solid electrolyte material prepared by the present invention has high ion conductivity and density, and the ternary positive electrode material coated by the solid electrolyte material also exhibits excellent thermal stability. DETAILED DESCRIPTION

[0017] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0018] As described in the background technology section of the present invention, the lithium aluminum titanium phosphate material in the prior art has the problem of low ion conductivity. In order to solve this problem, the present invention provides a solid electrolyte material, which includes a base material and a coating layer coated on the outer surface of the base material; wherein the structural formula of the base material is Li 1+x Al x Ti 2-x (PO4)3, 0.1≤x≤0.5, the material of the coating layer is ZnZr4(PO4)6.

[0019] The present invention coats the surface of the base material with ZnZr4(PO4)6. On the one hand, the introduction of ZnZr4(PO4)6 can increase the differential scanning calorimetry peak temperature of the solid electrolyte material, thereby improving the thermal stability and safety performance of the material. On the other hand, the introduction of ZnZr4(PO4)6 can also reduce the holes and gaps in the base, thereby increasing the density of the solid electrolyte material, and further improving the ionic conductivity of the solid electrolyte material.

[0020] In a preferred embodiment, in the structural formula of the matrix material, 0.2≤x≤0.4. For example, the matrix material may be Li 1.2 Al 0.2 Ti 1.8 (PO4)3、Li 1.3 Al 0.3 Ti 1.7 (PO4)3 or Li 1.4 Al 0.4 Ti 1.6 (PO4)3. Coating ZnZr4(PO4)6 on the surface of the above-mentioned matrix material can make the obtained electrolyte material have better thermal stability and safety performance, and can further improve the ionic conductivity of the solid electrolyte material.

[0021] Preferably, the ZnZr4(PO4)6 in the coating layer and the Li 1+x Al x Ti 2-x The molar ratio of (PO4)3 is (0.001-0.02):1. For example, it can be 0.001:1, 0.002:1, 0.003:1, 0.004:1, 0.005:1, 0.006:1, 0.007:1, 0.008:1, 0.009:1, 0.01:1, 0.011:1, 0.012:1, 0.013:1, 0.014:1, 0.015:1, 0.016:1, 0.017:1, 0.018:1, 0.019:1 or 0.02:1. 1+ x Al x Ti 2-x The (PO4)3 molar ratio is preferably within the above range, which can further improve the stability of the matrix material while further effectively reducing the number of pores and gaps in the matrix material, thereby further improving the density of the solid electrolyte material and further improving the ionic conductivity of the solid electrolyte material.

[0022] In order to further promote the improvement of the ionic conductivity of the solid electrolyte material, in a preferred embodiment, the density of the solid electrolyte material is 95-98%.

[0023] Another aspect of the present invention also provides a method for preparing the above-mentioned solid electrolyte material, which preparation method comprises the following steps: step S1, performing a first calcination on a first dispersion containing a zinc source, a zirconium source and a first phosphate source to obtain ZnZr4(PO4)6; step S2, mixing a second dispersion containing a lithium source, an aluminum source, a titanium source and a second phosphate source with the ZnZr4(PO4)6 and performing a second calcination to obtain the above-mentioned solid electrolyte material.

[0024] In the preparation method of the solid electrolyte material provided by the present invention, a person skilled in the art may firstly calcine a first dispersion liquid containing a zinc source, a zirconium source and a first phosphate source to obtain ZnZr4(PO4)6. Then, a second dispersion liquid containing a lithium source, an aluminum source, a titanium source and a second phosphate source is mixed with the ZnZr4(PO4)6 and calcined for a second time to finally obtain the above-mentioned solid electrolyte material. 1+x Al x Ti 2-x The Li, Al, Ti, and P sources in (PO4)3 are partially deposited with ZnZr4(PO4)6, thereby introducing ZnZr4(PO4)6 onto the outer surface of the matrix material. In this way, on the one hand, the introduction of ZnZr4(PO4)6 can increase the differential scanning calorimetry peak temperature of the solid electrolyte material, thereby making the thermal stability and safety performance of the material better. On the other hand, the introduction of ZnZr4(PO4)6 can also reduce the holes and gaps in the matrix, thereby increasing the density of the solid electrolyte material and further improving the ionic conductivity of the solid electrolyte material. In addition, the preparation method is easy to operate, has a simple process, is suitable for large-scale production, and has broad application prospects.

[0025] In a preferred embodiment, in the preparation step S1 of the solid electrolyte material, in order to obtain ZnZr4(PO4)6 with better stability and higher activity, so as to better introduce ZnZr4(PO4)6 into the LATP matrix material to improve the density of the solid electrolyte material, the pH value of the first dispersion is preferably 8 to 10. In order to make the above-mentioned zinc source, zirconium source and first phosphate source have better stability and uniformity in the first dispersion, the dispersant of the first dispersion is preferably one or more of anhydrous ethanol, anhydrous methanol or ethyl acetate; it is further preferred that the zinc source is selected from one or more of zinc sulfide, zinc carbonate or zinc chloride; it is further preferred that the zirconium source is selected from one or more of zirconium oxychloride, zirconium hydroxide or zirconium chloride; it is further preferred that the first phosphate source is selected from one or more of ammonium dihydrogen phosphate, phosphoric acid or diammonium hydrogen phosphate.

[0026] Further preferably, in the preparation process of the solid electrolyte material, in order to obtain ZnZr4(PO4)6 with better stability and higher activity, before the first calcination, the first dispersion is further subjected to the steps of first ball milling and first drying in sequence. Preferably, the processing speed of the first ball milling is 150-400 rpm, and the processing time is 2-5 hours; preferably, the processing temperature of the first drying is 90-110°C, and the processing time is 1-4 hours; further preferably, the processing temperature of the first calcination is 300-700°C, and the processing time is 6-12 hours.

[0027] In a preferred embodiment, in the step S2 of preparing the solid electrolyte material, in order to make the lithium source, aluminum source and second phosphate source have better stability and uniformity in the second dispersion, it is further beneficial to the matrix material Li 1+x Al x Ti 2-x The Li, Al, Ti, and P sources in (PO4)3 are deposited with ZnZr4(PO4)6, so that ZnZr4(PO4)6 is introduced into the matrix material to better increase the density of the matrix material and further improve the ionic conductivity of the solid electrolyte material. Preferably, the dispersant of the second dispersion is one or more of anhydrous ethanol, anhydrous methanol, or ethyl acetate; preferably, the molar ratio of ZnZr4(PO4)6 to the second phosphoric acid source is (0.001 to 0.02):3. For example, it can be 0.001:3, 0.002:3, 0.004:3, 0.006:3, 0.008:3, 0.010:3, 0.012:3, 0.014:3, 0.016:3, 0.018:3, or 0.02:3. Preferably, the lithium source is selected from one or more of lithium carbonate, lithium hydroxide or lithium oxide; the aluminum source is selected from one or more of aluminum oxide, aluminum hydroxide or aluminum chloride; the titanium source is selected from one or more of titanium oxide, titanium chloride or titanium hydroxide; the second phosphoric acid source is selected from one or more of ammonium dihydrogen phosphate, phosphoric acid or diammonium hydrogen phosphate. Based on this, the present invention can increase the density of the solid electrolyte material while improving the stability of the solid electrolyte material, thereby improving the ionic conductivity of the solid electrolyte material.

[0028] Further preferably, in the preparation process of the solid electrolyte material, in order to further increase the density of the solid electrolyte material, thereby improving the ionic conductivity of the solid electrolyte material. Before the second calcination, the preparation method also includes the steps of sequentially performing a second ball milling and a second drying on the second dispersion. Preferably, the processing speed of the second ball milling is 200-500rpm, and the processing time is 2-10h; preferably, the processing temperature of the second drying is 60-100°C, and the processing time is 4-8h; more preferably, the processing temperature of the second calcination is 850-950°C, and the processing time is 8-12h.

[0029] Another aspect of the present invention further provides a lithium ion solid-state battery, which comprises the above-mentioned solid-state electrolyte material, or the solid-state electrolyte material prepared by the above-mentioned method for preparing the solid-state electrolyte material. The lithium ion solid-state battery has higher electrical conductivity and better electrochemical performance.

[0030] Another aspect of the present invention further provides an application of a lithium-ion solid-state battery, which has a very broad application prospect in electric vehicles or electric bicycles.

[0031] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0032] Example 1

[0033] Step S1, subjecting a first dispersion liquid containing a zinc source, a zirconium source and a first phosphate source to a first ball milling, a first drying and a first calcining to obtain ZnZr4(PO4)6. The molar ratio of Zn, Zr and P in the above zinc source, zirconium source and first phosphate source is 1:4:6, the dispersant of the first dispersion liquid is anhydrous ethanol, the zinc source is zinc sulfide, the zirconium source is zirconyl chloride, the first phosphate source is ammonium dihydrogen phosphate, and the pH value of the first dispersion liquid is 8. The processing speed of the first ball milling is 150rpm, the processing time is 2h, the processing temperature of the first drying is 90°C, the processing time is 1h; the processing temperature of the first calcining is 300°C, and the processing time is 6h.

[0034] Step S2, mixing the second dispersion containing a lithium source, an aluminum source, a titanium source and a second phosphate source with the above-mentioned ZnZr4(PO4)6 for a second ball milling, a second drying and a second calcination to obtain a solid electrolyte material. Among them, the molar ratio of Li, Al, Ti and P in the above-mentioned lithium source, aluminum source, titanium source and second phosphate source is 1.1:0.1:1.9:3, the dispersant of the second dispersion is anhydrous ethanol, the lithium source is lithium carbonate, the aluminum source is aluminum oxide, the titanium source is titanium oxide, the second phosphate source is diammonium phosphate, and the molar ratio of ZnZr4(PO4)6 to the second phosphate source is 0.001:3. The processing speed of the second ball milling is 200rpm, the processing time is 2h, the processing temperature of the second drying is 60℃, and the processing time is 4h; the processing temperature of the second calcination is 850℃, and the processing time is 8h. The solid electrolyte material finally obtained has a ZnZr4(PO4)6 in the coating layer and a Li in the matrix material. 1+x Al x Ti 2-x The molar ratio of (PO4)3 is 0.001:1, and the structural formula of the solid electrolyte material is Li 1.1 Al 0.1 Ti 1.9 (PO4)3, density is 95.36%.

[0035] Example 2

[0036] Step S1, subjecting a first dispersion liquid containing a zinc source, a zirconium source and a first phosphate source to a first ball milling, a first drying and a first calcining to obtain ZnZr4(PO4)6. The molar ratio of Zn, Zr and P in the above zinc source, zirconium source and first phosphate source is 1:4:6, the dispersant of the first dispersion liquid is anhydrous ethanol, the zinc source is zinc carbonate, the zirconium source is zirconyl chloride, the first phosphate source is phosphoric acid, and the pH value of the first dispersion liquid is 8.5. The processing speed of the first ball milling is 200rpm, the processing time is 3h, the processing temperature of the first drying is 95°C, the processing time is 3.5h; the processing temperature of the first calcining is 400°C, and the processing time is 8h.

[0037] Step S2, mixing the second dispersion containing a lithium source, an aluminum source, a titanium source and a second phosphate source with the above-mentioned ZnZr4(PO4)6 for a second ball milling, a second drying and a second calcination to obtain a solid electrolyte material. Among them, the molar ratio of Li, Al, Ti and P in the above-mentioned lithium source, aluminum source, titanium source and second phosphate source is 1.2:0.2:1.8:3, the dispersant of the second dispersion is anhydrous ethanol, the lithium source is lithium hydroxide, the aluminum source is aluminum chloride, the titanium source is titanium oxide, the second phosphate source is diammonium phosphate, and the molar ratio of ZnZr4(PO4)6 to the second phosphate source is 0.0015:3. The processing speed of the second ball milling is 350rpm, the processing time is 4h, the processing temperature of the second drying is 80℃, and the processing time is 5h; the processing temperature of the second calcination is 870℃, and the processing time is 9h. The solid electrolyte material finally obtained has a ZnZr4(PO4)6 in the coating layer and a Li in the matrix material. 1+x Al x Ti 2-x The molar ratio of (PO4)3 is 0.0015:1, and the structural formula of the solid electrolyte material is Li 1.2 Al 0.2 Ti 1.8 (PO4)3, density is 95.51%.

[0038] Example 3

[0039] Step S1, subjecting a first dispersion liquid containing a zinc source, a zirconium source and a first phosphate source to a first ball milling, a first drying and a first calcining to obtain ZnZr4(PO4)6. The molar ratio of Zn, Zr and P in the zinc source, the zirconium source and the first phosphate source is 1:4:6, the dispersant of the first dispersion liquid is anhydrous ethanol, the zinc source is zinc carbonate, the zirconium source is zirconium hydroxide, the first phosphate source is phosphoric acid, and the pH value of the first dispersion liquid is 9. The processing speed of the first ball milling is 250rpm, the processing time is 3h, the processing temperature of the first drying is 100℃, the processing time is 2h; the processing temperature of the first calcining is 500℃, and the processing time is 9h.

[0040] Step S2, mixing the second dispersion containing a lithium source, an aluminum source, a titanium source and a second phosphate source with the above-mentioned ZnZr4(PO4)6 for a second ball milling, a second drying and a second calcination to obtain a solid electrolyte material. Among them, the molar ratio of Li, Al, Ti and P in the above-mentioned lithium source, aluminum source, titanium source and second phosphate source is 1.3:0.3:1.7:3, the dispersant of the second dispersion is anhydrous ethanol, the lithium source is lithium hydroxide, the aluminum source is aluminum chloride, the titanium source is titanium chloride, the second phosphate source is phosphoric acid, and the molar ratio of ZnZr4(PO4)6 to the second phosphate source is 0.0015:3. The processing speed of the second ball milling is 350rpm, the processing time is 6h, the processing temperature of the second drying is 80℃, and the processing time is 6h; the processing temperature of the second calcination is 900℃, and the processing time is 10h. The solid electrolyte material finally obtained has a ZnZr4(PO4)6 in the coating layer and a Li in the matrix material. 1+x Al x Ti 2-x The molar ratio of (PO4)3 is 0.0015:1, and the structural formula of the solid electrolyte material is Li 1.3 Al 0.3 Ti 1.7 (PO4)3, density is 96.87%.

[0041] Example 4

[0042] Step S1, subjecting a first dispersion liquid containing a zinc source, a zirconium source and a first phosphate source to a first ball milling, a first drying and a first calcining to obtain ZnZr4(PO4)6. The molar ratio of Zn, Zr and P in the zinc source, the zirconium source and the first phosphate source is 1:4:6, the dispersant of the first dispersion liquid is anhydrous ethanol, the zinc source is zinc chloride, the zirconium source is zirconium oxide, the first phosphate source is diammonium hydrogen phosphate, and the pH value of the first dispersion liquid is 8. The processing speed of the first ball milling is 300rpm, the processing time is 5h, the processing temperature of the first drying is 105℃, the processing time is 2h; the processing temperature of the first calcining is 500℃, and the processing time is 8h.

[0043] Step S2, mixing the second dispersion containing a lithium source, an aluminum source, a titanium source and a second phosphate source with the above-mentioned ZnZr4(PO4)6 for a second ball milling, a second drying and a second calcination to obtain a solid electrolyte material. Among them, the molar ratio of Li, Al, Ti and P in the above-mentioned lithium source, aluminum source, titanium source and second phosphate source is 1.4:0.4:1.6:3, the dispersant of the second dispersion is anhydrous ethanol, the lithium source is lithium carbonate, the aluminum source is aluminum oxychloride, the titanium source is titanium oxide, the second phosphate source is diammonium phosphate, and the molar ratio of ZnZr4(PO4)6 to the second phosphate source is 0.0019:3. The processing speed of the second ball milling is 500rpm, the processing time is 8h, the processing temperature of the second drying is 80℃, and the processing time is 7h; the processing temperature of the second calcination is 920℃, and the processing time is 10h. The solid electrolyte material finally obtained has a ZnZr4(PO4)6 in the coating layer and a Li in the matrix material. 1+x Al x Ti 2-x The molar ratio of (PO4)3 is 0.0019:1, and the structural formula of the solid electrolyte material is Li 1.4 Al 0.4 Ti 1.6 (PO4)3, density is 96.41%.

[0044] Example 5

[0045] Step S1, subjecting a first dispersion liquid containing a zinc source, a zirconium source and a first phosphate source to a first ball milling, a first drying and a first calcining to obtain ZnZr4(PO4)6. The molar ratio of Zn, Zr and P in the above zinc source, zirconium source and first phosphate source is 1:4:6, the dispersant of the first dispersion liquid is anhydrous ethanol, the zinc source is zinc carbonate, the zirconium source is zirconyl chloride, the first phosphate source is phosphoric acid, and the pH value of the first dispersion liquid is 9.5. The processing speed of the first ball milling is 300rpm, the processing time is 5h, the processing temperature of the first drying is 105℃, the processing time is 1h; the processing temperature of the first calcining is 380℃, and the processing time is 10h.

[0046] Step S2, mixing the second dispersion containing a lithium source, an aluminum source, a titanium source and a second phosphate source with the above-mentioned ZnZr4(PO4)6 for a second ball milling, a second drying and a second calcination to obtain a solid electrolyte material. Among them, the molar ratio of Li, Al, Ti and P in the above-mentioned lithium source, aluminum source, titanium source and second phosphate source is 1.2:0.2:1.8:3, the dispersant of the second dispersion is anhydrous ethanol, the lithium source is lithium carbonate, the aluminum source is aluminum oxychloride, the titanium source is titanium chloride, the second phosphate source is phosphoric acid, and the molar ratio of ZnZr4(PO4)6 to the second phosphate source is 0.0015:3. The processing speed of the second ball milling is 400rpm, the processing time is 7h, the processing temperature of the second drying is 100℃, and the processing time is 7h; the processing temperature of the second calcination is 850℃, and the processing time is 10h. The solid electrolyte material finally obtained has a ZnZr4(PO4)6 in the coating layer and a Li in the matrix material. 1+x Al x Ti 2-x The molar ratio of (PO4)3 is 0.0015:1, and the structural formula of the solid electrolyte material is Li 1.2 Al 0.2 Ti 1.8 (PO4)3, density is 96.21%.

[0047] Example 6

[0048] Step S1, subjecting a first dispersion liquid containing a zinc source, a zirconium source and a first phosphate source to a first ball milling, a first drying and a first calcining to obtain ZnZr4(PO4)6. The molar ratio of Zn, Zr and P in the zinc source, the zirconium source and the first phosphate source is 1:4:6, the dispersant of the first dispersion liquid is anhydrous ethanol, the zinc source is zinc chloride, the zirconium source is zirconium chloride, the first phosphate source is diammonium hydrogen phosphate, and the pH value of the first dispersion liquid is 10. The processing speed of the first ball milling is 400rpm, the processing time is 5h, the processing temperature of the first drying is 110℃, the processing time is 4h; the processing temperature of the first calcining is 700℃, and the processing time is 12h.

[0049] Step S2, mixing the second dispersion containing a lithium source, an aluminum source, a titanium source and a second phosphate source with the above-mentioned ZnZr4(PO4)6 for a second ball milling, a second drying and a second calcination to obtain a solid electrolyte material. Among them, the molar ratio of Li, Al, Ti and P in the above-mentioned lithium source, aluminum source, titanium source and second phosphate source is 1.5:0.5:1.5:3, the dispersant of the second dispersion is anhydrous ethanol, the lithium source is lithium oxide, the aluminum source is aluminum chloride, the titanium source is titanium chloride, the second phosphate source is diammonium hydrogen phosphate, and the molar ratio of ZnZr4(PO4)6 to the second phosphate source is 0.02:3. The processing speed of the second ball milling is 500rpm, the processing time is 10h, the processing temperature of the second drying is 100℃, and the processing time is 8h; the processing temperature of the second calcination is 950℃, and the processing time is 12h. The solid electrolyte material finally obtained has a ZnZr4(PO4)6 in the coating layer and a Li in the matrix material. 1+x Al x Ti 2-x The molar ratio of (PO4)3 is 0.02:1, and the structural formula of the solid electrolyte material is Li 1.5 Al 0.5 Ti 1.5 (PO4)3, density is 95.41%.

[0050] Comparative Example 1

[0051] Step S2, subjecting the second dispersion liquid containing a lithium source, an aluminum source, a titanium source and a second phosphate source to a second ball milling, a second drying and a second calcining to obtain a solid electrolyte material. Among them, the molar ratio of Li, Al, Ti and P in the above-mentioned lithium source, aluminum source, titanium source and second phosphate source is 1.3:0.3:1.7:3, the dispersant of the second dispersion liquid is anhydrous ethanol, the lithium source is lithium hydroxide, the aluminum source is aluminum chloride, the titanium source is titanium chloride, and the second phosphate source is phosphoric acid. The processing speed of the second ball milling is 350rpm, the processing time is 6h, the processing temperature of the second drying is 80°C, and the processing time is 6h; the processing temperature of the second calcination is 900°C, and the processing time is 10h. The unmodified solid electrolyte material finally obtained has the structural formula of Li 1.3 Al 0.3 Ti 1.7 (PO4)3, density is 86.40%.

[0052] Comparative Example 2

[0053] Step S1, subjecting a first dispersion liquid containing a zinc source, a zirconium source and a first phosphate source to a first ball milling, a first drying and a first calcining to obtain ZnZr4(PO4)6. The molar ratio of Zn, Zr and P in the zinc source, the zirconium source and the first phosphate source is 1:4:6, the dispersant of the first dispersion liquid is anhydrous ethanol, the zinc source is zinc carbonate, the zirconium source is zirconium hydroxide, the first phosphate source is phosphoric acid, and the pH value of the first dispersion liquid is 9. The processing speed of the first ball milling is 250rpm, the processing time is 3h, the processing temperature of the first drying is 100℃, the processing time is 2h; the processing temperature of the first calcining is 500℃, and the processing time is 9h.

[0054] Step S2, mixing the second dispersion containing a lithium source, an aluminum source, a titanium source and a second phosphate source with the above-mentioned ZnZr4(PO4)6 for a second ball milling, a second drying and a second calcination to obtain a solid electrolyte material. Among them, the molar ratio of Li, Al, Ti and P in the above-mentioned lithium source, aluminum source, titanium source and second phosphate source is 1.3:0.3:1.7:3, the dispersant of the second dispersion is anhydrous ethanol, the lithium source is lithium hydroxide, the aluminum source is aluminum chloride, the titanium source is titanium chloride, the second phosphate source is phosphoric acid, and the molar ratio of ZnZr4(PO4)6 to the second phosphate source is 0.0005:3. The processing speed of the second ball milling is 350rpm, the processing time is 6h, the processing temperature of the second drying is 80℃, and the processing time is 6h; the processing temperature of the second calcination is 900℃, and the processing time is 10h. The solid electrolyte material finally obtained has a ZnZr4(PO4)6 in the coating layer and a Li in the matrix material. 1+x Al x Ti 2-x The molar ratio of (PO4)3 is 0.0005:1, and the structural formula of the solid electrolyte material is Li 1.3 Al 0.3 Ti 1.7 (PO4)3, density is 90.20%.

[0055] Comparative Example 3

[0056] Step S1, subjecting a first dispersion liquid containing a zinc source, a zirconium source and a first phosphate source to a first ball milling, a first drying and a first calcining to obtain ZnZr4(PO4)6. The molar ratio of Zn, Zr and P in the zinc source, the zirconium source and the first phosphate source is 1:4:6, the dispersant of the first dispersion liquid is anhydrous ethanol, the zinc source is zinc carbonate, the zirconium source is zirconium hydroxide, the first phosphate source is phosphoric acid, and the pH value of the first dispersion liquid is 9. The processing speed of the first ball milling is 250rpm, the processing time is 3h, the processing temperature of the first drying is 100℃, the processing time is 2h; the processing temperature of the first calcining is 500℃, and the processing time is 9h.

[0057] Step S2, mixing the second dispersion containing a lithium source, an aluminum source, a titanium source and a second phosphate source with the above-mentioned ZnZr4(PO4)6 for a second ball milling, a second drying and a second calcination to obtain a solid electrolyte material. Among them, the molar ratio of Li, Al, Ti and P in the above-mentioned lithium source, aluminum source, titanium source and second phosphate source is 1.3:0.3:1.7:3, the dispersant of the second dispersion is anhydrous ethanol, the lithium source is lithium hydroxide, the aluminum source is aluminum chloride, the titanium source is titanium chloride, the second phosphate source is phosphoric acid, and the molar ratio of ZnZr4(PO4)6 to the second phosphate source is 0.025:3. The processing speed of the second ball milling is 350rpm, the processing time is 6h, the processing temperature of the second drying is 80℃, and the processing time is 6h; the processing temperature of the second calcination is 900℃, and the processing time is 10h. The solid electrolyte material finally obtained has a ZnZr4(PO4)6 in the coating layer and a Li in the matrix material. 1+x Al x Ti 2-x The molar ratio of (PO4)3 is 0.025:1, and the structural formula of the solid electrolyte material is Li 1.3 Al 0.3 Ti 1.7 (PO4)3, density is 91.20%.

[0058] Performance Testing:

[0059] (1) Density

[0060] The present invention adopts the Archimedes drainage method to test the density, specifically, an electronic balance is used to measure the mass of the solid electrolyte material before and after the Archimedes drainage method test, so as to determine the actual density of the sample, thereby calculating the density.

[0061] (2) Ionic conductivity

[0062] The solid electrolyte material is made into a disc sample to be tested, and the AC impedance of different response frequencies is recorded using an electrochemical workstation. Different electrode processes with different reaction time constants are analyzed, and the ionic conductivity of the solid electrolyte material is obtained through fitting, analysis, and calculation.

[0063] (3) Differential scanning calorimetry peak temperature

[0064] The differential scanning calorimetry peak temperature is measured when the ternary positive electrode material coated with the solid electrolyte material is heated from room temperature to 400°C at a heating rate of 10°C / min in a compressed air atmosphere.

[0065] The solid electrolytes prepared in the above examples and comparative examples were tested, and the results are shown in Table 1 below:

[0066] Table 1

[0067] Density / % <![CDATA[Ionic conductivity × 10 -4 / S / cm]]> Differential scanning calorimetry peak temperature / ℃ Example 1 95.36 2.41 216.5 Example 2 95.51 2.71 217.4 Example 3 96.87 3.62 220.1 Example 4 96.41 3.41 219.8 Example 5 96.21 2.75 217.6 Example 6 95.41 2.45 218.5 Comparative Example 1 86.4 0.87 201.4 Comparative Example 2 90.2 1.04 204.3 Comparative Example 3 91.2 1.08 203.2

[0068] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0069] From the data of Examples 1, 2, 3, 4, 5, 6 and Comparative Example 1, it can be found that when the solid electrolyte material provided by the present invention is used, and the solid electrolyte material includes a base material and a coating layer coated on the outer surface of the base material; wherein the structural formula of the base material is Li 1+x Al x Ti 2-x (PO4)3, 0.1≤x≤0.5, when the material of the coating layer is ZnZr4(PO4)6, the obtained solid electrolyte has a higher density (for example, 95.36% of Example 1, 95.51% of Example 2, 96.87% of Example 3, 96.41% of Example 4, 96.21% of Example 5 or 95.41% of Example 6), and based on this, it also has a higher ionic conductivity (for example, 2.41×10 -4 / S / cm, 2.71×10 -4 / S / cm, 3.62×10 -4 / S / cm, 3.41×10 -4 / S / cm, 2.75×10 -4 / S / cm or 2.45×10 -4 / S / cm), and also has excellent thermal stability. When the solid electrolyte material is not modified, the density of the solid electrolyte is poor (for example, 86.4% of Comparative Example 1), and the corresponding ionic conductivity is also low (for example, 0.87×10 -4 / S / cm), and the thermal stability performance is also poor.

[0070] From the data of Examples 1, 2, 3, 4, 5, 6 and Comparative Examples 2 and 3, it can be found that when the solid electrolyte of the present invention is used, the ZnZr4(PO4)6 in the coating layer and the Li 1+x Al x Ti 2-xWhen the molar ratio of (PO4)3 is in the range of (0.001 to 0.02):1, the solid electrolyte has a higher density (for example, 95.36% in Example 1, 95.51% in Example 2, 96.87% in Example 3, 96.41% in Example 4, 96.21% in Example 5, or 95.41% in Example 6), and the molar ratio of ZnZr4(PO4)6 to the second phosphate source is (0.001 to 0.02):3. Based on this, it also has a higher ionic conductivity (for example, 2.41×10 -4 / S / cm, 2.71×10 -4 / S / cm, 3.62×10 -4 / S / cm, 3.41×10 -4 / S / cm, 2.75×10 -4 / S / cm or 2.45×10 -4 / S / cm), and also has excellent thermal stability. When the ZnZr4(PO4)6 in the coating layer and the Li 1+x Al x Ti 2-x When the molar ratio of (PO4)3 is outside the range of (0.001-0.02):1 (e.g., 0.0005:1 in Comparative Example 2 or 0.025:1 in Comparative Example 3), and the molar ratio of ZnZr4(PO4)6 to the second phosphoric acid source is outside the range of (0.001-0.02):3 (e.g., 0.0005:3 in Comparative Example 2 or 0.025:3 in Comparative Example 3), the density of the solid electrolyte is low (e.g., 90.2% in Comparative Example 2 or 91.2% in Comparative Example 3), which leads to a decrease in ionic conductivity (e.g., 1.04×10 -4 / S / cm or 1.08×10 -4 / S / cm), and the thermal stability is also poor.

[0071] From the data of Examples 2, 3, 4, 5 and Examples 1, 6, it can be found that when the solid electrolyte of the present invention is used, the structural formula of the matrix material is Li 1+x Al x Ti 2-x (PO4)3, and in the range of 0.2≤x≤0.4, the solid electrolyte has a higher density (95.51% in Example 2, 96.87% in Example 3, 96.41% in Example 4, and 96.21% in Example 5), and based on this, it also has a higher ionic conductivity (for example, 2.71×10 -4 / S / cm, 3.62×10 -4 / S / cm, 3.41×10 -4 / S / cm, 2.75×10 -4 / S / cm), and also has better thermal stability. When the structural formula of the matrix material is Li 1+x Al x Ti 2-x (PO4)3, and when the value of x is outside the range of 0.2≤x≤0.4 (e.g., 0.1 in Example 1 or 0.5 in Example 6), the solid electrolyte has a higher density (e.g., 95.36% in Example 1 or 95.41% in Example 6), and based on this, it also has a higher ionic conductivity (e.g., 2.41×10 -4 / S / cm or 2.45×10 -4 / S / cm), and also has excellent thermal stability.

[0072] In summary, the solid electrolyte material prepared by the present invention has high ionic conductivity and density, and the ternary positive electrode material coated therewith also exhibits excellent thermal stability.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A solid electrolyte material, characterized in that: The solid electrolyte material comprises a base material and a coating layer coated on the outer surface of the base material; wherein, The structural formula of the matrix material is Li 1+x Al x Ti 2-x (PO4)3, 0.1≤x≤0.5; The material of the coating layer is ZnZr4(PO4)6; The ZnZr4(PO4)6 in the coating layer and the Li 1+x Al x Ti 2-x The molar ratio of (PO4)3 is (0.001~0.02):1; The density of the solid electrolyte material is 95-98%.

2. The solid electrolyte material according to claim 1, characterized in that In the structural formula of the matrix material, 0.2≤x≤0.

4.

3. A method for preparing the solid electrolyte material according to claim 1 or 2, characterized in that: The preparation method comprises the following steps: Step S1, performing a first calcination on a first dispersion containing a zinc source, a zirconium source and a first phosphate source to obtain ZnZr4(PO4)6; Step S2, mixing a second dispersion containing a lithium source, an aluminum source, a titanium source and a second phosphate source with the ZnZr4(PO4)6 and performing a second calcination to obtain the solid electrolyte material.

4. The method for preparing a solid electrolyte material according to claim 3, characterized in that: The pH value of the first dispersion liquid is 8-10.

5. The method for preparing a solid electrolyte material according to claim 3, characterized in that: The dispersant of the first dispersion liquid is one or more of anhydrous ethanol, anhydrous methanol or ethyl acetate.

6. The method for preparing a solid electrolyte material according to claim 3, characterized in that: The zinc source is selected from one or more of zinc sulfide, zinc carbonate or zinc chloride.

7. The method for preparing a solid electrolyte material according to claim 3, characterized in that: The zirconium source is selected from one or more of zirconium oxychloride, zirconium hydroxide or zirconium chloride.

8. The method for preparing a solid electrolyte material according to claim 3, characterized in that: The first phosphate source is selected from one or more of diammonium phosphate, phosphoric acid or diammonium hydrogen phosphate.

9. The method for preparing a solid electrolyte material according to claim 3, characterized in that: Before the first calcination, the preparation method further includes the steps of sequentially performing a first ball milling and a first drying on the first dispersion.

10. The method for preparing a solid electrolyte material according to claim 9, characterized in that: The processing speed of the first ball mill is 150-400 rpm, and the processing time is 2-5 hours.

11. The method for preparing a solid electrolyte material according to claim 9, characterized in that: The first drying process has a temperature of 90-110° C. and a time of 1-4 hours.

12. The method for preparing a solid electrolyte material according to claim 3, characterized in that: The treatment temperature of the first calcination is 300-700° C., and the treatment time is 6-12 hours.

13. The method for preparing a solid electrolyte material according to claim 3, characterized in that: The dispersant of the second dispersion is one or more of anhydrous ethanol, anhydrous methanol or ethyl acetate.

14. The method for preparing a solid electrolyte material according to claim 3, characterized in that: The molar ratio of the ZnZr4(PO4)6 to the second phosphoric acid source is (0.001-0.02):

3.

15. The method for preparing a solid electrolyte material according to claim 3, characterized in that: The lithium source is selected from one or more of lithium carbonate, lithium hydroxide or lithium oxide.

16. The method for preparing a solid electrolyte material according to claim 3, characterized in that: The aluminum source is selected from one or more of aluminum oxide, aluminum hydroxide or aluminum chloride.

17. The method for preparing a solid electrolyte material according to claim 3, characterized in that: The titanium source is selected from one or more of titanium oxide, titanium chloride or titanium hydroxide.

18. The method for preparing a solid electrolyte material according to claim 3, characterized in that: The second phosphoric acid source is selected from one or more of diammonium phosphate, phosphoric acid or diammonium hydrogen phosphate.

19. The method for preparing a solid electrolyte material according to claim 3, characterized in that: Before the second calcination, the preparation method further includes the steps of sequentially performing a second ball milling and a second drying on the second dispersion.

20. The method for preparing a solid electrolyte material according to claim 19, characterized in that: The processing speed of the second ball mill is 200-500 rpm, and the processing time is 2-10 hours.

21. The method for preparing a solid electrolyte material according to claim 19, characterized in that: The second drying process has a temperature of 60-100° C. and a time of 4-8 hours.

22. The method for preparing a solid electrolyte material according to claim 19, characterized in that: The second calcination has a treatment temperature of 850-950° C. and a treatment time of 8-12 hours.

23. A lithium-ion solid-state battery, characterized in that: The lithium-ion solid-state battery comprises the solid-state electrolyte material according to claim 1 or 2, or a solid-state electrolyte material prepared by the method for preparing a solid-state electrolyte material according to any one of claims 3 to 22.

24. An application of the lithium-ion solid-state battery according to claim 23, characterized in that: Application of the lithium-ion solid-state battery in electric vehicles or electric bicycles.