Solid-state electrolyte material, method for preparing the same, and solid-state battery

Abstract

The application provides a solid-state electrolyte material, a preparation method thereof and a solid-state battery, the solid-state electrolyte material comprises electrolyte powder, the electrolyte powder is spherical and / or spheroidal, the average particle size of the electrolyte powder is 40nm to 200nm, the morphology of the electrolyte powder is spherical and / or spheroidal, and the particle size of the solid-state electrolyte material is nanoscale, which is beneficial to the formation of stable cubic phase LLZO of the solid-state electrolyte material, helps to improve the ionic conductivity of the solid-state electrolyte, and thus solves the technical problem that the ionic conductivity is reduced due to the doping of metal elements.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, and in particular to a solid-state electrolyte material, a preparation method thereof and a solid-state battery. BACKGROUND

[0002] Lithium lanthanum zirconium oxide (LLZO) with a garnet structure is a key component of current oxide solid-state electrolytes. LLZO is divided into two types, tetragonal phase and cubic phase, wherein cubic phase LLZO (c-LLZO) has high ionic conductivity, a wide electrochemical window and acid-base stability, and high stability to lithium.

[0003] In related technologies, doping a specific metal element in LLZO can significantly improve the room temperature stability of cubic phase LLZO, and lithium vacancies formed after doping can effectively improve the transmission channel of lithium ions, thereby significantly improving the ionic conductivity of cubic phase LLZO.

[0004] However, for solid-state electrolytes doped with a specific metal element, the doped metal element can affect the growth of crystal grains in the solid-state electrolyte, increase the particle size of the solid-state electrolyte powder, and thus affect the ionic conductivity of the solid-state electrolyte. SUMMARY

[0005] Embodiments of the present application provide a solid-state electrolyte material, a preparation method thereof and a solid-state battery, which can improve the technical problem of affecting the ionic conductivity of the solid-state electrolyte due to the doping of metal elements.

[0006] In a first aspect, embodiments of the present application provide a solid-state electrolyte material, which includes electrolyte powder, the electrolyte powder being spherical and / or spheroidal; and / or

[0007] The average particle size of the electrolyte powder is 40 nm to 200 nm.

[0008] In an embodiment, the average particle size of the electrolyte powder is 70 nm to 120 nm.

[0009] In an embodiment, the solid-state electrolyte material includes a substance with a chemical formula as follows:

[0010] Li a La3Zr b M c O 12 ;

[0011] wherein M is any one of the doped metals Al, Ta, Ti and Ga;

[0012] The value of a is greater than or equal to 5 and less than or equal to 7;

[0013] b is greater than or equal to 1.2 and less than or equal to 2;

[0014] c is greater than or equal to 0.1 and less than or equal to 0.7.

[0015] In an embodiment, M has a valence of k, and a, b, c, k satisfy a+4b+kc=15.

[0016] In an embodiment, M is Al;

[0017] The solid-state electrolyte material comprises a substance with a chemical formula as follows:

[0018] Li 7-3c La3Zr2Al c O 12 , wherein c is in a range of 0.2 to 0.4.

[0019] In an embodiment, M is Ti;

[0020] The solid-state electrolyte material comprises a substance with a chemical formula as follows:

[0021] Li7La3Zr 2-c Ti c O 12 , wherein c is in a range of 0.5 to 0.7.

[0022] In an embodiment, M is Ta;

[0023] The solid-state electrolyte material comprises a substance with a chemical formula as follows:

[0024] Li 7-c La3Zr 2-c Ta c O 12 , wherein c is in a range of 0.3 to 0.7.

[0025] In an embodiment, the solid-state electrolyte material has an electrical conductivity of 0.62×10 -3 ~1.24×10 -3 at 25°C.

[0026] In a second aspect, embodiments of the present application provide a preparation method of a solid-state electrolyte material, comprising the following steps:

[0027] providing a lanthanum salt, a zirconium salt, a lithium salt, and a doping metal salt;

[0028] dissolving the lanthanum salt, the zirconium salt, and the doping metal salt in a first solvent to obtain a first mixed solution;

[0029] carrying out gasification treatment on the first mixed solution to obtain an LZO precursor;

[0030] The LZO precursor was wet-mixed with lithium salt and dried to obtain the LLZO precursor.

[0031] The LLZO precursor was sintered in the solid phase at a temperature range of 400°C to 600°C to obtain the solid electrolyte material as described above.

[0032] In one embodiment, the lanthanum salt includes at least one of lanthanum acetate, lanthanum isobutyrate, lanthanum propoxide, lanthanum isopropoxide, lanthanum oxalate, lanthanum phosphate, lanthanum triacetate, and lanthanum terephthalate; and / or

[0033] The zirconium salt includes at least one of zirconium acetate, zirconium butyrate, zirconium isobutyrate, zirconium propoxide, zirconium isopropoxide, and zirconium benzoate; and / or

[0034] The lithium salt includes any one of lithium hydroxide and lithium carbonate; and / or

[0035] The first solvent includes one or more combinations of propionic acid, ethanol, isopropanol, and isooctanoic acid;

[0036] The doped metal salt includes any one of aluminum salt, tantalum salt, gallium salt, and titanium salt.

[0037] In one embodiment, the first mixture is further subjected to the following steps before vaporization:

[0038] The first mixture is stirred until it is completely dissolved and clear before proceeding with the vaporization process; and / or

[0039] The gasification process includes any one of spray pyrolysis, spray drying, and flame spray pyrolysis.

[0040] Thirdly, embodiments of the present invention provide a solid-state battery, including the aforementioned solid-state electrolyte material or the solid-state electrolyte material prepared by the aforementioned method.

[0041] The beneficial effects of the embodiments of the present invention are as follows:

[0042] In the embodiments of the present invention, since the solid electrolyte material includes electrolyte powder, the electrolyte powder is spherical and / or near-spherical in shape, and the average particle size of the electrolyte powder is at the nanometer level, it is beneficial to form a stable cubic phase LLZO, which helps to improve the ionic conductivity of the solid electrolyte material, thereby improving the technical problem of reduced ionic conductivity due to doping with metal elements. Attached Figure Description

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings in the following description only show some of the embodiments of the present application, and all other drawings obtained by those skilled in the art without creative effort based on these drawings also belong to the protection scope of the present application.

[0044] Fig. 1 is a transmission electron microscope image of the solid-state electrolyte material provided by the embodiment of the present application;

[0045] Fig. 2 is a scanning electron microscope image of the solid-state electrolyte material provided by the embodiment of the present application. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort belong to the protection scope of the present application. In addition, it should be understood that the specific embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application. In the present application, the orientation words such as "upper" and "lower" generally refer to the upper and lower in the actual use or working state of the device, and specifically refer to the direction of the drawing surface in the drawings; and "inner" and "outer" refer to the outline of the device.

[0047] In the related art, doping a specific metal element in LLZO can significantly improve the room temperature stability of cubic phase LLZO, and the lithium vacancy formed after doping can effectively improve the transmission channel of lithium ions, thereby significantly improving the ionic conductivity of cubic phase LLZO.

[0048] However, for the solid-state electrolyte doped with a specific metal element, the doped metal element may affect the growth of the crystal grains in the solid-state electrolyte, increase the particle size of the solid-state electrolyte powder, and thus affect the ionic conductivity of the solid-state electrolyte.

[0049] Therefore, according to a first aspect of the present application, a solid-state electrolyte material is provided, which comprises electrolyte powder, the electrolyte powder being spherical and / or spheroidal; and / or

[0050] The average particle size of the electrolyte powder is 40 nm to 200 nm.

[0051] It should be noted that the electrolyte powder is nanoscale and spherical and / or spheroidal, Figs. 1-2 which is beneficial to improve the ionic conductivity of cubic phase LLZO. This is because:

[0052] 1. The spherical or spheroid electrolyte powder is easier to form a dense structure in a pyrolysis process, and the surface is more uniform and has fewer defects. The dense structure helps to reduce the resistance of ion transmission, thereby improving the ionic conductivity.

[0053] 2. The electrolyte powder is spherical or spheroid, which is beneficial to make the diffusion path of lithium ions more uniform and continuous. The cubic phase LLZO has an isotropic three-dimensional lithium ion diffusion path, which is beneficial to the rapid migration of lithium ions.

[0054] It should be noted that the average particle size refers to the d90 particle diameter, and the d90 particle diameter refers to the diameter of the particle whose cumulative volume corresponds to 90% of the volume in the particle size distribution.

[0055] In some embodiments of the present application, the average particle size of the electrolyte powder is 70 nm to 120 nm. Exemplarily, the average particle size of the electrolyte powder is 70 nm, 75 nm, 80 nm, 85 nm, 90 nm, 95 nm, 100 nm, 105 nm, 110 nm, 115 nm, 120 nm, and any value between any two adjacent values in the above.

[0056] In some embodiments of the present application, the solid-state electrolyte material comprises a substance of the following chemical formula:

[0057] Li a La3Zr b M c O 12 ;

[0058] Wherein, M is any one of the doping metals Al, Ta, Ti, and Ga;

[0059] The value of a is greater than or equal to 5 and less than or equal to 7;

[0060] The value of b is greater than or equal to 1.2 and less than or equal to 2;

[0061] The value of c is greater than or equal to 0.1 and less than or equal to 0.7.

[0062] In some embodiments of the present application, if the valence state of M is k, then a, b, c, and k satisfy a+4b+kc=15.

[0063] It should be noted that the valence state of M refers to the potential highest valence state of the metal ion corresponding to M. Exemplarily, M is a doping metal Al, and the valence state of M is 3; M is a doping metal Zr, and the valence state of M is 4.

[0064] The embodiments of the present application provide a solid-state electrolyte material, which has a chemical formula of Lia La3Zr b M c O 12 , the value range of a, b, c is limited, that is, the doping ratio of the doping metal is limited. By adjusting the doping ratio of the doping metal, a cubic phase with stable structure can be prepared, thereby improving the ionic conductivity of the solid electrolyte material. If the content of the doping metal is higher than the above interval, the lithium content will be too low, thereby reducing the ionic conductivity of the solid electrolyte. If the content of the doping metal is lower than the above interval, the solid electrolyte will tend to form a tetragonal phase LLZO, thereby reducing the stability of the structure of the solid electrolyte.

[0065] In some embodiments of the present application, when the doping metal M is Al, the chemical formula of the solid electrolyte material can be Li 7-3c La3Zr2Al c O 12 , and the value range of c is 0.2 to 0.4. Further, the value range of c can be 0.25 to 0.35. For example, the value of c can be 0.25, 0.26, 0.27, 0.28, 0.29, 0.30, 0.31, 0.32, 0.33, 0.34, 0.35, and any value between the above two adjacent values.

[0066] In some embodiments of the present application, when the doping metal M is Ti, the chemical formula of the solid electrolyte material is Li7La3Zr 2-c Ti c O 12 , and the value range of c is 0.5 to 0.7. Further, the value range of c is 0.55 to 0.65. For example, the value of c can be 0.55, 0.56, 0.57, 0.58, 0.59, 0.60, 0.61, 0.62, 0.63, 0.64, 0.65, and any value between the above two adjacent values.

[0067] In some embodiments of the present application, when the doping metal M is Ta, the chemical formula of the solid electrolyte material is Li 7- c La3Zr 2-c Ta c O 12 , and the value range of c is 0.3 to 0.7. Further, the value range of c is 0.5 to 0.6. For example, the value of c can be 0.5, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.60, and any value between the above two adjacent values.

[0068] In some embodiments of the present application, the solid-state electrolyte material can have an electrical conductivity at 25℃ in the range of 0.75*10 -3 ~1.24*10 -3 Further, the solid-state electrolyte material can have an electrical conductivity at 25℃ of 0.94*10 -3 ~1.2*10 -3 , 1.07*10 -3 ~1.18*10 -3 or 1.16*10 -3 ~1.22*10 -3 .

[0069] Currently, the synthesis routes of LLZO include solid phase and wet methods. Among them, the solid phase method is the most ideal large-scale production scheme at present because of its high yield and simple method. However, the solid phase method has a high reaction temperature and the prepared material has a large particle size, which limits its large-scale application.

[0070] In the related art, the synthesis reaction temperature is reduced by changing the doping ratio, but this easily leads to incomplete reaction, resulting in high impurity content in the final product.

[0071] Therefore, the second aspect of the present application provides a preparation method of a solid-state electrolyte material, comprising the following steps:

[0072] S100, providing a lanthanum salt, a zirconium salt, a lithium salt and a doping metal salt;

[0073] S200, dissolving the lanthanum salt, the zirconium salt and the doping metal salt in a first solvent to obtain a first mixed solution;

[0074] S300, performing gasification treatment on the first mixed solution to obtain an LZO precursor;

[0075] S400, performing wet ball milling on the LZO precursor and the lithium salt, and drying to obtain an LLZO precursor;

[0076] S500, performing solid phase sintering on the LLZO precursor in a temperature range of 400℃ to 600℃ to obtain the aforementioned solid-state electrolyte material.

[0077] The preparation method of the solid-state electrolyte material provided in the embodiments of the present application first dissolves the lanthanum salt, the zirconium salt and the doping metal salt in a solvent to prepare a first mixed solution, and performs gasification treatment on the first mixed solution to obtain an LZO precursor. The lanthanum salt, the zirconium salt and the doping metal salt can volatilize in the gasification process to form a precursor powder with better dispersibility and smaller particle size, thereby greatly increasing the surface energy and being conducive to reducing the subsequent synthesis reaction temperature and realizing the preparation of cubic phase LLZO with high purity.

[0078] In some embodiments of the present application, in step S100, the lanthanum salt can include an organic lanthanum salt. Further, the organic lanthanum salt can include at least one of lanthanum acetate, lanthanum isobutyrate, lanthanum propyl alcohol, lanthanum isopropyl alcohol, lanthanum oxalate, lanthanum phosphate, lanthanum triacetate, lanthanum terephthalate. Further, the organic lanthanum salt can include lanthanum acetate or lanthanum terephthalate.

[0079] In some embodiments of the present application, in step S100, the lanthanum salt can also include an inorganic lanthanum salt, and the inorganic lanthanum salt includes any one of lanthanum nitrate, lanthanum carbonate, lanthanum sulfate.

[0080] In some embodiments of the present application, in step S100, the zirconium salt can include an organic zirconium salt. Further, the organic zirconium salt can include at least one of zirconium acetate, zirconium butyrate, zirconium isobutyrate, zirconium n-propyl alcohol, zirconium isopropyl alcohol, zirconium benzoate. Further, the organic zirconium salt can also include zirconium n-propyl alcohol or zirconium propylate.

[0081] In some embodiments of the present application, in step S100, the zirconium salt can also include an inorganic zirconium salt, and the inorganic zirconium salt includes any one of zirconium nitrate, zirconium carbonate, zirconium sulfate.

[0082] In some embodiments of the present application, in step S100, the lithium salt can include any one of lithium hydroxide, lithium carbonate. Further, the lithium salt can include lithium hydroxide hydrate.

[0083] In some embodiments of the present application, in step S100, the doped metal salt can include any one of aluminum salt, tantalum salt, gallium salt, titanium salt. Further, the aluminum salt can include at least one of trimethylaluminum, triphenylaluminum, triethylaluminum, aluminum n-propyl alcohol, aluminum isopropyl alcohol, aluminum propionate. Further, the tantalum salt can include diphenyl tantalate or triphenyl tantalate. Further, the gallium salt can include gallium isopropyl alcohol. Further, the titanium salt can include tetrabutyl titanate.

[0084] In some embodiments of the present application, in step S100, the gasification treatment is to facilitate the volatilization of the doped metal salt, so as to form precursor particles with better dispersivity and smaller particle size, greatly increase the surface energy, and facilitate the reduction of the subsequent synthesis temperature.

[0085] In some embodiments of the present application, in step S200, the first solvent can include one or more combinations of propionic acid, ethanol, isopropyl alcohol, isooctanoic acid. Further, the first solvent can include a combination of propionic acid and isopropyl alcohol or a combination of ethanol and isooctanoic acid. The double solvent is to improve the solute dispersivity, adjust the particle formation and deposition process in the spraying process, optimize the volatility and combustion rate in the spraying process, and adjust the liquid drop surface tension.

[0086] In some embodiments of the present application, in step S300, the gasification treatment comprises any one of SP (spray pyrolysis), SD (spray drying), and FSP (flame spray pyrolysis).

[0087] In some embodiments of the present application, in step S300, before the first mixed solution is subjected to the gasification treatment, the first mixed solution further comprises the following steps:

[0088] The first mixed solution is stirred, and after complete dissolution and clarification, the gasification treatment is performed.

[0089] In some embodiments of the present application, in step S300, the gasification treatment comprises any one of spray pyrolysis, flame spray pyrolysis, and spray drying.

[0090] In some embodiments of the present application, in step S400, the wet ball milling can use solvents such as water, isopropyl alcohol, and ethanol.

[0091] In some embodiments of the present application, the solid-state electrolyte material prepared in step S500 is a cubic phase crystal structure, referred to as c-LLZO.

[0092] In some embodiments of the present application, in step S500, during the solid-phase sintering, the temperature is raised at a rate of 1-10°C / min to 400-600°C. Further, the temperature is raised at a rate of 2-8°C / min to 450-550°C.

[0093] In some embodiments of the present application, in step S500, after the temperature is raised to 400-600°C, the temperature is maintained for 0.5-12 h.

[0094] The synthesis temperature in the preparation method of the embodiments of the present application is relatively low, so the degree of lithium excess is much lower than that of the prior art, which can reduce the cost and reduce the possibility of lithium compounds in the target product.

[0095] According to a third aspect of the present application, a solid-state battery is provided, comprising the solid-state electrolyte material prepared by the preparation method of the solid-state electrolyte material.

[0096] The present application will be described in detail below through specific embodiments. The following embodiments are only part of the embodiments of the present application and are not limiting of the present application. The raw materials used in the following embodiments are commercially available products unless otherwise specified.

[0097] Example 1

[0098] A solid-state electrolyte material is prepared by the following method:

[0099] The lanthanum salt is lanthanum acetate, the zirconium salt is zirconium n-propoxide, the doping metal salt is aluminum isopropoxide, the lithium salt is lithium hydroxide monohydrate, and the solvent is a combination of propionic acid and isopropyl alcohol in a volume ratio of 1:1;

[0100] The lanthanum acetate, the zirconium n-propoxide, the aluminum isopropoxide and the lithium hydroxide monohydrate are prepared according to a molar ratio of 3:2:0.32:6.04;

[0101] The lanthanum acetate, the zirconium n-propoxide and the aluminum isopropoxide are sequentially added into the solvent to obtain a first mixed solution;

[0102] The first mixed solution is subjected to gasification treatment by a spray dryer, the inlet temperature is 350℃, and the outlet temperature is 150℃, to obtain an LZO precursor;

[0103] The LZO precursor and the lithium hydroxide monohydrate are dissolved in water, wet ball milling is performed at a rotating speed of 400 rpm for 12 h, and drying is performed to obtain p-LLZO;

[0104] The p-LLZO is subjected to solid-phase sintering by a rotary furnace at a temperature rising rate of 3℃ / min to 450℃, and the temperature is maintained for 1 h to obtain c-LLZO.

[0105] Example 2

[0106] A solid-state electrolyte material, which is different from example 1 in that the molar ratio of lanthanum acetate, zirconium n-propoxide, aluminum isopropoxide and lithium hydroxide monohydrate is different. In this embodiment, the molar ratio of lanthanum acetate, zirconium n-propoxide, aluminum isopropoxide and lithium hydroxide monohydrate is 3:2:0.2:6.4.

[0107] Example 3

[0108] A solid-state electrolyte material, which is different from example 1 in that the molar ratio of lanthanum acetate, zirconium n-propoxide, aluminum isopropoxide and lithium hydroxide monohydrate is different. In this embodiment, the molar ratio of lanthanum acetate, zirconium n-propoxide, aluminum isopropoxide and lithium hydroxide monohydrate is 3:2:0.4:5.8.

[0109] Example 4

[0110] A solid-state electrolyte material, which is different from example 1 in that the molar ratio of lanthanum acetate, zirconium n-propoxide, aluminum isopropoxide and lithium hydroxide monohydrate is different. In this embodiment, the molar ratio of lanthanum acetate, zirconium n-propoxide, aluminum isopropoxide and lithium hydroxide monohydrate is 3:2:0.1:6.7.

[0111] Example 5

[0112] A solid-state electrolyte material, which is different from Example 1 in that the molar ratio of lanthanum acetate, zirconium n-propylate, aluminum isopropylate, and hydrated lithium hydroxide is different. In this example, the molar ratio of lanthanum acetate, zirconium n-propylate, aluminum isopropylate, and hydrated lithium hydroxide is 3:2:0.5:5.5.

[0113] Example 6

[0114] A solid-state electrolyte material, which is different from Example 1 in that the lanthanum salt and the aluminum salt are different. In this example, the lanthanum salt is lanthanum terephthalate, the zirconium salt is zirconium n-propylate, and the aluminum salt is trimethylaluminum.

[0115] Example 7

[0116] A solid-state electrolyte material, which is different from Example 1 in that the solvent is different. In this example, the solvent is a combination of ethanol and isooctanoic acid in a volume ratio of 1:1.

[0117] Example 8

[0118] A solid-state electrolyte material, which is different from Example 1 in that M is different. In this example, the doping metal salt is tetrabutyl titanate, and the molar ratio of lanthanum acetate, zirconium n-propylate, tetrabutyl titanate, and hydrated lithium hydroxide is 3:1.5:0.5:7.

[0119] Example 9

[0120] A solid-state electrolyte material, which is different from Example 8 in that the molar ratio of lanthanum acetate, zirconium n-propylate, tetrabutyl titanate, and hydrated lithium hydroxide is different. In this example, the molar ratio of lanthanum acetate, zirconium n-propylate, tetrabutyl titanate, and hydrated lithium hydroxide is 3:1.45:0.55:7.

[0121] Example 10

[0122] A solid-state electrolyte material, which is different from Example 8 in that the molar ratio of lanthanum acetate, zirconium n-propylate, tetrabutyl titanate, and hydrated lithium hydroxide is different. In this example, the molar ratio of lanthanum acetate, zirconium n-propylate, tetrabutyl titanate, and hydrated lithium hydroxide is 3:1.4:0.6:7.

[0123] Example 11

[0124] A solid-state electrolyte material, which is different from Example 8 in that the molar ratio of lanthanum acetate, zirconium n-propylate, tetrabutyl titanate, and hydrated lithium hydroxide is different. In this example, the molar ratio of lanthanum acetate, zirconium n-propylate, tetrabutyl titanate, and hydrated lithium hydroxide is 3:1.35:0.65:7.

[0125] Example 12

[0126] A solid state electrolyte material, which differs from Example 8 in that the molar ratio of lanthanum acetate, zirconium n-propoxide, tetrabutyl titanate and hydrated lithium hydroxide is different. In this example, the molar ratio of lanthanum acetate, zirconium n-propoxide, tetrabutyl titanate and hydrated lithium hydroxide is 3: 1.3: 0.7: 7.

[0127] Example 13

[0128] A solid state electrolyte material, which differs from Example 1 in that M is different. In this example, the dopant metal salt is diphenyltantalum acid, and the molar ratio of lanthanum acetate, zirconium n-propoxide, diphenyltantalum acid and hydrated lithium hydroxide is 3: 1.7: 0.3: 6.7.

[0129] Example 14

[0130] A solid state electrolyte material, which differs from Example 13 in that the molar ratio of lanthanum acetate, zirconium n-propoxide, diphenyltantalum acid and hydrated lithium hydroxide is different. In this example, the molar ratio of lanthanum acetate, zirconium n-propoxide, diphenyltantalum acid and hydrated lithium hydroxide is 3: 1.5: 0.5: 6.5.

[0131] Example 15

[0132] A solid state electrolyte material, which differs from Example 13 in that the molar ratio of lanthanum acetate, zirconium n-propoxide, diphenyltantalum acid and hydrated lithium hydroxide is different. In this example, the molar ratio of lanthanum acetate, zirconium n-propoxide, diphenyltantalum acid and hydrated lithium hydroxide is 3: 1.45: 0.55: 6.45.

[0133] Example 16

[0134] A solid state electrolyte material, which differs from Example 13 in that the molar ratio of lanthanum acetate, zirconium n-propoxide, diphenyltantalum acid and hydrated lithium hydroxide is different. In this example, the molar ratio of lanthanum acetate, zirconium n-propoxide, diphenyltantalum acid and hydrated lithium hydroxide is 3: 1.4: 0.6: 6.4.

[0135] Example 17

[0136] A solid state electrolyte material, which differs from Example 13 in that the molar ratio of lanthanum acetate, zirconium n-propoxide, diphenyltantalum acid and hydrated lithium hydroxide is different. In this example, the molar ratio of lanthanum acetate, zirconium n-propoxide, diphenyltantalum acid and hydrated lithium hydroxide is 3: 1.3: 0.7: 6.3.

[0137] Example 18

[0138] A solid-state electrolyte material, which is different from example 1 in that the gasification treatment adopts the method of flame spray pyrolysis, specifically comprising: gasifying the first mixed liquid through a flame spray pyrolysis reactor, the liquid inlet rate is 7 ml / min, the oxygen dispersion rate is 6 L / min, the methane-oxygen ratio is 0.5, and the LZO precursor is obtained.

[0139] Example 19

[0140] A solid-state electrolyte material, which is different from example 1 in that the temperature of solid-phase sintering is different. In this embodiment, the temperature of the solid-phase sintering process is raised to 400℃, and the remaining steps remain consistent with example 1.

[0141] Example 20

[0142] A solid-state electrolyte material, which is different from example 1 in that the temperature of solid-phase sintering is different. In this embodiment, the temperature of the solid-phase sintering process is raised to 500℃ and kept for 30 min, and the remaining steps remain consistent with example 1.

[0143] Example 21

[0144] A solid-state electrolyte material, which is different from example 1 in that the temperature of solid-phase sintering is different. In this embodiment, the temperature of the solid-phase sintering process is raised to 600℃ and kept for 30 min, and the remaining steps remain consistent with example 1.

[0145] Comparative Example 1

[0146] A solid-state electrolyte material, which is different from example 1 in that the molar ratio of lanthanum acetate, zirconium n-propyl alcohol, aluminum isopropyl alcohol, and hydrated lithium hydroxide is different. In this embodiment, lanthanum acetate, zirconium n-propyl alcohol, aluminum isopropyl alcohol, and hydrated lithium hydroxide are configured according to the molar ratio of 3:2:0.05:6.85.

[0147] Comparative Example 2

[0148] A solid-state electrolyte material, which is different from example 1 in that the molar ratio of lanthanum acetate, zirconium n-propyl alcohol, aluminum isopropyl alcohol, and hydrated lithium hydroxide is different. In this embodiment, lanthanum acetate, zirconium n-propyl alcohol, aluminum isopropyl alcohol, and hydrated lithium hydroxide are configured according to the molar ratio of 3:2:0.8:4.6.

[0149] Detection method:

[0150] 1. Particle size test:

[0151] The morphology of the powder in the examples and comparative examples is observed and the particle size is measured by scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

[0152] 2. Ion conductivity test:

[0153] The powders of solid electrolyte materials of the examples and the comparative examples were pressed into tablets on ceramic green bodies by a tablet press, and then the pressed ceramic green bodies were placed in a crucible and put in a tube furnace to be heated to 1150℃ for 2h to obtain ceramic tablets, and the conductivity of the ceramic tablets was tested by a conductivity meter:

[0154] The conductivity σ was obtained by the calculation formula σ = L / RS, R was the resistance value measured above, L was the thickness value of the electrolyte tablet, and S was the electrode area, and the conductivity at room temperature (25℃) was calculated.

[0155] The average particle size and ionic conductivity of the examples and the comparative examples are shown in Table 1.

[0156] Table 1

[0157]

[0158] Compared with Examples 1-5 and Comparative Examples 1-2, the difference between Example 1-3 is that the molar ratio of aluminum isopropoxide is changed, i.e., the doping amount of Al in the solid electrolyte is changed. As can be seen from Table 1, when the doping amount of Al is 0.2 to 0.4, the average particle size of the prepared solid electrolyte material is 72nm to 88nm, the particle size is moderate, and the ionic conductivity of the solid electrolyte reaches 0.94S / cm to 1.2S / cm. Example 4 reduces the doping amount of Al and reduces the amount of aluminum salt input, and accordingly, the average particle size of the prepared solid electrolyte powder is also reduced, and the ionic conductivity of the solid electrolyte also decreases. Example 5 increases the molar ratio of aluminum isopropoxide, i.e., increases the doping amount of Al, and the particle size of the prepared solid electrolyte powder changes little, but the ionic conductivity of the solid electrolyte decreases slightly. Comparative Example 1 significantly reduces the doping amount of Al, and accordingly, the average particle size of the prepared solid electrolyte material no longer continues to decrease, and the ionic conductivity continues to decrease, only 0.60S / cm; Comparative Example 2 increases the doping amount of Al, so that the value of c reaches 0.8, and the particle size of the prepared solid electrolyte is similar to the average particle size of Example 3, but the ionic conductivity of the solid electrolyte decreases significantly.

[0159] Compared with Examples 1-5 and Comparative Examples 1-2, the difference between Example 1-3 is that the molar ratio of aluminum isopropoxide is changed, i.e., the doping amount of Al in the solid electrolyte is changed. As can be seen from Table 1, when the doping amount of Al is 0.2 to 0.4, the average particle size of the prepared solid electrolyte material is 72nm to 88nm, the particle size is moderate, and the ionic conductivity of the solid electrolyte reaches 0.94S / cm to 1.2S / cm. Example 4 reduces the doping amount of Al and reduces the amount of aluminum salt input, and accordingly, the average particle size of the prepared solid electrolyte powder is also reduced, and the ionic conductivity of the solid electrolyte also decreases. Example 5 increases the molar ratio of aluminum isopropoxide, i.e., increases the doping amount of Al, and the particle size of the prepared solid electrolyte powder changes little, but the ionic conductivity of the solid electrolyte decreases slightly. Comparative Example 1 significantly reduces the doping amount of Al, and accordingly, the average particle size of the prepared solid electrolyte material no longer continues to decrease, and the ionic conductivity continues to decrease, only 0.60S / cm; Comparative Example 2 increases the doping amount of Al, so that the value of c reaches 0.8, and the particle size of the prepared solid electrolyte is similar to the average particle size of Example 3, but the ionic conductivity of the solid electrolyte decreases significantly.

[0160] Compared with Example 1, Example 8 uses tetrabutyl titanate as a doping metal salt, and Examples 9-12 change the addition amount of tetrabutyl titanate. As can be seen from Table 1, as the addition amount of tetrabutyl titanate increases, the particle size of the prepared solid-state electrolyte becomes larger, but is within the range of 90-120 nm. The ionic conductivity of the prepared solid-state electrolyte increases first and then decreases. When the addition amount of tetrabutyl titanate exceeds 0.6, the ionic conductivity of the solid-state electrolyte no longer continues to increase, but shows a downward trend.

[0161] Compared with Example 1, Example 13 uses diphenyl tantalate as a doping metal salt, and Examples 14-17 change the addition amount of diphenyl tantalate. As can be seen from Table 1, as the molar ratio of diphenyl tantalate increases, the average particle size of the prepared solid-state electrolyte powder also gradually increases, but the ionic conductivity increases first and then decreases. In particular, when the c value of the doping metal salt is 0.5 to 0.6, the ionic conductivity of the prepared solid-state electrolyte remains at a high level.

[0162] Compared with Example 1, Example 18 changes the way of gasification treatment. As can be seen from Table 1, the average particle size and ionic conductivity of the prepared solid-state electrolyte are similar to the test results of Example 1.

[0163] Compared with Example 1, Examples 19-21 change the solid-phase sintering temperature. As can be seen from Table 1, when the solid-phase sintering temperature is between 400°C and 600°C, solid-state electrolytes with high ionic conductivity can be obtained, and a lower solid-state sintering temperature is achieved when preparing solid-state electrolytes.

[0164] In summary, when the doping metal is Al and the doping ratio of Al is 0.2 to 0.4, when the doping metal is Ti and the doping ratio of Ti is 0.55 to 0.65, and when the doping metal is Ta and the doping ratio of Ta is 0.5 to 0.6, the prepared solid-state electrolyte can obtain high ionic conductivity, which indicates that when the above ratio is doped, a stable cubic phase can be formed by doping, thereby improving the ionic conductivity of the solid-state electrolyte. However, if the doping ratio is higher than this range, the lithium content will be too low, and the excessive vacancies will reduce the ionic conductivity; if the doping ratio is lower than this range, the solid-state electrolyte will tend to form a tetragonal phase, which is not conducive to the stability of the overall structure of the solid-state electrolyte.

[0165] The above has carried out the detailed introduction to the embodiment of the application, the principle and implementation mode of the application have been described by applying specific examples in this paper, the above embodiment description is only used for helping understanding the method of the application and its core idea; at the same time, for the person skilled in the art, according to the idea of the application, there will be changes in specific implementation mode and application range, and the above is described, the content of the specification should not be understood as the limitation of the application.

Claims

1. A solid-state electrolyte material, characterized in that, the solid-state electrolyte material comprises electrolyte powder, the electrolyte powder is spherical; wherein the average particle size of the electrolyte powder is 72 nm to 120 nm; the preparation method of the electrolyte powder comprises the following steps: providing lanthanum salt, zirconium salt, lithium salt and doped metal salt; dissolving the lanthanum salt, zirconium salt and doped metal salt in a solvent to obtain a first mixed solution; carrying out gasification treatment on the first mixed solution to obtain an LZO precursor; wherein the gasification treatment comprises any one of spray pyrolysis, spray drying, flame spray pyrolysis; wet mixing the LZO precursor, lithium salt, and stirring to obtain an LLZO precursor; sintering the LLZO precursor at a temperature range of 450°C to 550°C to obtain the electrolyte powder; The electrolyte powder has an electrical conductivity of 0.94 x 10 -3 ~1.2 x 10 -3 at 25°C. the electrolyte powder comprises a substance with a chemical formula as follows: Li a La3Zr b M c O 12 ; wherein the M is selected as Al, the solid-state electrolyte material comprises a substance with a chemical formula as follows: Li 7-3c La3Zr2Al c O 12 wherein c has a value ranging from 0.2 to 0.4; or the M is selected as Ti, the solid-state electrolyte material comprises a substance with a chemical formula as follows: Li7La3Zr 2-c Ti c O 12 wherein c has a value ranging from 0.55 to 0.65; or the M is Ta, the solid-state electrolyte material comprises a substance with a chemical formula as follows: Li 7-c La3Zr 2-c Ta c O 12 wherein c has a value ranging from 0.5 to 0.

6.

2. The solid-state electrolyte material of claim 1, wherein, The valence of M is k, and a, b, c, k satisfy a+4b+kc=15.

3. The solid-state electrolyte material of claim 1, characterized in that, the lanthanum salt comprises at least one of lanthanum acetate, lanthanum isobutyrate, lanthanum propyl alcohol, lanthanum isopropyl alcohol, lanthanum oxalate, lanthanum phosphate, lanthanum triacetate, and lanthanum terephthalate; and / or the zirconium salt comprises at least one of zirconium acetate, zirconium butyrate, zirconium isobutyrate, zirconium propyl alcohol, zirconium isopropyl alcohol, and zirconium benzoate; and / or the lithium salt comprises any one of lithium hydroxide and lithium carbonate; and / or the solvent comprises one or more combinations of propionic acid, ethanol, isopropyl alcohol, and isooctanoic acid; the doped metal salt comprises any one of aluminum salt, tantalum salt, gallium salt, and titanium salt.

4. The solid-state electrolyte material of claim 3, characterized in that, the first mixed solution further comprises the following steps before gasification treatment: stirring the first mixed solution, and then carrying out gasification treatment after stirring to complete dissolution and clarification.

5. A solid-state battery, characterized by, The solid-state electrolyte material of any one of claims 1 to 4.

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