Oxide solid electrolyte and method for manufacturing same, lithium battery, and battery pack

Abstract

The present application relates to the field of oxide solid electrolyte, and particularly relates to an oxide solid electrolyte, a preparation method thereof, a lithium battery and a battery pack. The oxide solid electrolyte comprises a substrate and a surface coating layer coating the substrate; the chemical composition of the substrate satisfies the chemical formula Li 7‑x M 1 x La 3‑y M 2 y Zr 2‑z M 3 z O 12‑u X u , and the chemical composition of the surface coating layer satisfies the chemical formula Li v E w G h O l By limiting the optional elements of M 1 , M 2 , M 3 , X, E and G and the numerical range of x, y, z, u, v, w, h and l, multi-site element doping can be realized, and a uniform ion conductor coating layer can be formed on the surface of the primary particles of the electrolyte, so that the ion conductivity and the stability of the structure and surface of the lithium lanthanum zirconium oxide solid electrolyte can be greatly improved.

Description

Technical Field

[0001] This invention relates to the field of oxide solid electrolytes, specifically to an oxide solid electrolyte and its preparation method, lithium batteries, and battery packs. Background Technology

[0002] With the rapid development of the power battery and energy storage battery market, higher demands are being placed on the energy density and safety performance of lithium-ion batteries. Traditional lithium-ion batteries, due to the use of electrolytes in their structure, have significant safety risks and are limited to using lithium-free negative electrodes, thus the potential for increasing battery energy density has reached a bottleneck. Solid-state batteries, by using solid electrolytes instead of traditional electrolytes, can fundamentally solve battery safety issues. Furthermore, by using lithium-containing negative electrodes instead of traditional graphite or silicon-carbon negative electrodes, they can further improve battery energy density and have become the recognized next-generation lithium battery development direction.

[0003] In solid-state battery systems, one of the most critical materials is the solid electrolyte. Solid electrolytes include oxide solid electrolytes, sulfide solid electrolytes, polymer solid electrolytes, and organic-inorganic composite solid electrolytes. Lithium lanthanum zirconium oxide, as a type of oxide solid electrolyte, has become one of the most promising solid electrolytes for industrialization due to its advantages such as high conductivity, good thermal stability, and wide electrochemical window.

[0004] The lithium lanthanum zirconium oxide solid electrolyte exhibits both tetragonal and cubic phase structures, with the tetragonal phase sample showing a lower ionic conductivity of only 10. -6 The S / cm value is not practical; cubic phase samples have higher ionic conductivity, typically reaching 10. -4 -10 -3 S / cm is a key area of ​​focus and development. In actual preparation, cubic lithium lanthanum zirconium oxide (LXI) is structurally unstable at room temperature and easily transforms into a tetragonal phase. Furthermore, when stored and used in air, LXI readily decomposes, precipitating lithium carbonate on its surface, reducing its ionic conductivity, especially when the particle size reaches the nanometer scale. These issues significantly hinder the practical application of LXI.

[0005] In existing technologies, research on the modification of lithium lanthanum zirconium oxide solid electrolytes focuses on stabilizing their cubic phase structure through elemental doping, thereby improving their ionic conductivity. CN110247107A discloses a solid electrolyte, its preparation method, and its applications. This invention introduces trivalent, non-volatile elements such as In, Er, and Ho into the lithium lanthanum zirconium oxide solid electrolyte to achieve doping at La ion sites, thereby improving the cubic structural stability of the material. The doping of La ion sites increases the volume of tetrahedral vacancies, thus improving the ionic conductivity of the electrolyte. However, this invention has a limited effect on improving ionic conductivity. Furthermore, it does not address the problem of residual lithium carbonate on the surface of lithium lanthanum zirconium oxide, failing to promote the practical application of lithium lanthanum zirconium oxide. Summary of the Invention

[0006] The purpose of this invention is to overcome the unsatisfactory improvement effect of lithium lanthanum zirconium oxide solid electrolyte in the prior art, and to solve the problem of lithium carbonate precipitation on the surface of lithium lanthanum zirconium oxide solid electrolyte reducing conductivity. The invention provides an oxide solid electrolyte, its preparation method, lithium battery, and battery pack.

[0007] To achieve the above objectives, a first aspect of the present invention provides a lithium lanthanum zirconium oxide solid electrolyte, the electrolyte comprising: a substrate and a surface coating layer covering the substrate;

[0008] The chemical composition of the matrix satisfies the chemical formula Li 7-x M 1 x La 3-y M 2 y Zr 2-z M 3 z O 12-u X u , of which M 1 It is at least one element selected from Ba, Fe, B, Zn, Al, Ga, and Ge; M 2 It is at least one element selected from Rb, Sr, Ba, Ca, Y, Bi, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Ac; M 3 X is at least one element selected from Mg, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Ge, Se, Tc, Ru, Rh, Pd, Cd, In, Sn, Sb, Te, I, Hf, Ir, Pt, Tl, Pb, Ce, Pu, Np, Y, Ta, Nb, Mo, and W; X is at least one element selected from F, Cl, Br, I, and S; 0 ≤ x < 0.1, 0 ≤ y ≤ 0.1, 0 ≤ z ≤ 0.5, and 0 ≤ u ≤ 0.1.

[0009] The chemical composition of the surface coating layer satisfies the chemical formula Li v E w G h O l Where E is at least one element among Al, Ti, and Zr; G is at least one element among Al, Ti, Zr, and Mg; 0.5≤v≤10, 0.5≤w≤7, 0.5≤h≤7, and 1≤l≤15.

[0010] A second aspect of this invention provides a method for preparing a lithium lanthanum zirconium oxide solid electrolyte, the method comprising:

[0011] (1) Compounds containing Li and compounds containing element M 1 Compounds, compounds containing La, compounds containing element M 2 Compounds, Zr-containing compounds, compounds containing element M 3 Compounds and compounds containing element X are prepared and mixed to obtain a mixture;

[0012] (2) The mixture is calcined to obtain a lithium lanthanum zirconium oxide body;

[0013] (3) The lithium-containing lanthanum zirconium oxide, the solution or nano-sized sol containing elements E and G, and the solvent are subjected to sand milling treatment, and then the resulting slurry is dried to obtain an electrolyte precursor;

[0014] (3) The electrolyte precursor is heat-treated in an oxygen-containing atmosphere to obtain a lithium lanthanum zirconium oxide solid electrolyte.

[0015] The third aspect of the present invention provides a lithium lanthanum zirconium oxide solid electrolyte prepared by the preparation method described in the second aspect above.

[0016] A fourth aspect of the present invention provides a lithium battery containing the lithium lanthanum zirconium oxide solid electrolyte described in the first or third aspect above.

[0017] A fifth aspect of the present invention provides a battery pack comprising the lithium battery described in the fourth aspect above.

[0018] Through the above technical solution, the present invention has the following beneficial effects:

[0019] (1) The ion conductor coated multi-site doped lithium lanthanum zirconium oxygen solid electrolyte provided by the present invention adopts multi-site element doping, and under the premise of stabilizing cubic phase structure, it significantly improves ionic conductivity through multiple effects such as forming lithium vacancies, increasing lithium content in octahedral sites, and increasing lattice constant.

[0020] (2) The ion conductor-coated multi-site doped lithium lanthanum zirconium oxide solid electrolyte provided by the present invention effectively reduces the residual lithium carbonate content on the sample surface by introducing a coating material that can consume lithium carbonate during the preparation process, thereby further improving the ionic conductivity of the sample.

[0021] (3) The ion conductor coated multi-site doped lithium lanthanum zirconium oxide solid electrolyte provided by the present invention has a uniform ion conductor coating layer on the surface of the primary particles, which acts as a barrier on the surface of the solid electrolyte, preventing further reaction between the solid electrolyte and air, preventing secondary generation of lithium carbonate on the sample surface, improving the stability of the sample surface to air, and maintaining high ion conductivity during storage and use.

[0022] (4) This invention provides a method for preparing a multi-site doped lithium lanthanum zirconium oxide solid electrolyte coated with an ion conductor. A cubic phase matrix with high ionic conductivity is prepared by a solid-state method. Further, a liquid-phase coating combined with a sand milling process is used to achieve a uniform distribution of the coating element compound on the matrix surface. Combined with subsequent heat treatment, this method achieves the goal of constructing a uniform ion conductor coating layer on the matrix surface while consuming residual lithium carbonate. This can significantly improve the ionic conductivity, structure, and surface stability of the lithium lanthanum zirconium oxide solid electrolyte.

[0023] (5) The preparation method provided by the present invention is easy to operate, the introduction of doping elements and uniform ionic conductor coating layer is simple, and the improvement effect on material properties is significant. Attached Figure Description

[0024] Figure 1 This is a scanning electron microscope image of the lithium lanthanum zirconium oxide solid electrolyte prepared in Example 1.

[0025] Figure 2 The image shows a scanning electron microscope (SEM) image of the lithium lanthanum zirconium oxide solid electrolyte prepared in Comparative Example 1.

[0026] Figure 3 This is a high-resolution transmission electron microscope image of the lithium lanthanum zirconium oxide solid electrolyte prepared in Example 1. Detailed Implementation

[0027] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0028] In one aspect, the present invention provides a lithium lanthanum zirconium oxide solid electrolyte, the electrolyte comprising: a substrate and a surface coating layer covering the substrate;

[0029] The chemical composition of the matrix satisfies the chemical formula Li 7-x M 1 x La 3-y M 2 y Zr 2-z M 3 z O 12-u X u , of which M 1 It is at least one element selected from Ba, Fe, B, Zn, Al, Ga, and Ge; M 2 It is at least one element selected from Rb, Sr, Ba, Ca, Y, Bi, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Ac; M 3 X is at least one element selected from Mg, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Ge, Se, Tc, Ru, Rh, Pd, Cd, In, Sn, Sb, Te, I, Hf, Ir, Pt, Tl, Pb, Ce, Pu, Np, Y, Ta, Nb, Mo, and W; X is at least one element selected from F, Cl, Br, I, and S; 0 ≤ x < 0.1, 0 ≤ y ≤ 0.1, 0 ≤ z ≤ 0.5, and 0 ≤ u ≤ 0.1.

[0030] The chemical composition of the surface coating layer satisfies the chemical formula Li v E w G h O l Where E is at least one element among Al, Ti, and Zr; G is at least one element among Al, Ti, Zr, and Mg; 0.5≤v≤10, 0.5≤w≤7, 0.5≤h≤7, and 1≤l≤15.

[0031] In some embodiments of the present invention, the chemical composition of the matrix satisfies the chemical formula Li 7-x M 1 x La 3- y M 2 y Zr 2-z M 3 z O 12-u X u Based on this, in order to achieve higher ionic conductivity in the lithium lanthanum zirconium oxide solid electrolyte, preferably, M 1 It is at least one element selected from B, Al, Ga, and Ge; M 2 M is at least one element selected from Sr, Ba, Y, Nd, Pm, Sm, Dy, Ho, and Er; 3X is at least one element selected from Mg, Sc, Ti, Ge, Se, Tc, Ru, In, Hf, Ir, Pt, Y, Ta, Nb, Mo, and W; X is at least one element selected from F, Cl, I, and S; 0 ≤ x < 0.07, 0 ≤ y ≤ 0.03, 0 ≤ z ≤ 0.3, and 0 ≤ u ≤ 0.08.

[0032] In some embodiments of the present invention, the chemical composition of the surface coating layer satisfies Li v E w G h O l Based on this, in order to enable the surface coating layer to more effectively act as a barrier and prevent the secondary formation of lithium carbonate on the surface of the solid electrolyte, thereby enabling the lithium lanthanum zirconium oxide solid electrolyte to have higher ionic conductivity and stability, preferably, E is at least one element selected from Ti and Zr; G is at least one element selected from Al, Ti, and Zr; 1≤v≤8, 1≤w≤5, 1≤h≤5, 2≤l≤12.

[0033] In some embodiments of the present invention, the average particle size D of the lithium lanthanum zirconium oxide solid electrolyte is... 50 The substrate has an average particle size of 0.1-5 μm; further, the average particle size of the substrate is <4.5 μm, and the thickness of the surface coating layer is <0.5 μm; the weight ratio of the substrate to the surface coating layer is 100:(0.05-40). The relatively small substrate particle size and thin surface coating layer can shorten the lithium-ion diffusion path and are also beneficial for preparing thinner solid electrolyte membranes.

[0034] In this invention, the garnet structure of the lithium lanthanum zirconium oxide solid electrolyte comprises an octahedral LaO8 dodecahedron (24c) and a hexacoordinated ZrO6 octahedron (16a). Lithium ions randomly occupy either two interstitial sites (48g) or off-center sites (96h). The 24d tetrahedron is coplanarly connected to four adjacent octahedra, forming a three-dimensional transport network. By increasing the lithium content in the octahedra, lithium ions are induced to transport through the path of lowest activation energy, i.e., the triangular bottleneck formed by the coplanar octahedra and tetrahedrons, effectively improving lithium ion conductivity. High-resolution transmission electron microscopy reveals that the number of lithium atoms at the corresponding octahedral positions is between 5 and 7. By introducing element doping, on the one hand, the charge balance around lithium ions is regulated to form lithium vacancies. On the other hand, the introduced elements have large atomic sizes, which can act as pillars during lithium ion migration and increase the migration path size. In high-resolution transmission electron microscopy, large heteroatoms and a certain degree of point defects can be observed near the lithium atom positions. By measuring the cell size or calculating through electron diffraction results, a significant increase in the lattice constant can be found.

[0035] A second aspect of this invention provides a method for preparing a lithium lanthanum zirconium oxide solid electrolyte, the method comprising:

[0036] (1) Compounds containing Li and compounds containing element M 1 Compounds, compounds containing La, compounds containing element M 2 Compounds, Zr-containing compounds, compounds containing element M 3 Compounds and compounds containing element X are prepared and mixed to obtain a mixture;

[0037] (2) The mixture is calcined to obtain a lithium lanthanum zirconium oxide body;

[0038] (3) The lithium-containing lanthanum zirconium oxide, the solution or nano-sized sol containing elements E and G, and the solvent are subjected to sand milling treatment, and then the resulting slurry is dried to obtain an electrolyte precursor;

[0039] (3) The electrolyte precursor is heat-treated in an oxygen-containing atmosphere to obtain a lithium lanthanum zirconium oxide solid electrolyte.

[0040] In some embodiments of the present invention, in step (1), M 1 It can be at least one element selected from Ba, Fe, B, Zn, Al, Ga, and Ge; M 2 It can be at least one element selected from Rb, Sr, Ba, Ca, Y, Bi, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Ac; M 3 X can be at least one element selected from Mg, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Ge, Se, Tc, Ru, Rh, Pd, Cd, In, Sn, Sb, Te, I, Hf, Ir, Pt, Tl, Pb, Ce, Pu, Np, Y, Ta, Nb, Mo, and W; X can be at least one element selected from F, Cl, Br, I, and S; preferably, M 1 It is at least one element selected from B, Al, Ga, and Ge; M 2 M is at least one element selected from Sr, Ba, Y, Nd, Pm, Sm, Dy, Ho, and Er; 3 X is at least one element selected from Mg, Sc, Ti, Ge, Se, Tc, Ru, In, Hf, Ir, Pt, Y, Ta, Nb, Mo, and W; X is at least one element selected from F, Cl, I, and S.

[0041] In some embodiments of the present invention, in step (1), the Li-containing compound and the element M-containing compound are... 1 Compounds, compounds containing La, compounds containing element M 2 Compounds, Zr-containing compounds, compounds containing element M 3The amount of compound and compound containing element X fed in the feed must satisfy the chemical formula Li 7-x M 1 x La 3-y M 2 y Zr 2-z M 3 z O 12-u X u In the given condition, 0 ≤ x < 0.1, 0 ≤ y ≤ 0.1, 0 ≤ z ≤ 0.5, and 0 ≤ u ≤ 0.1; preferably, it satisfies the chemical formula Li 7-x M 1 x La 3-y M 2 y Zr 2-z M 3 z O 12-u X u In the range 0≤x<0.07, 0≤y≤0.03, 0≤z≤0.3, 0≤u≤0.08.

[0042] In some embodiments of the present invention, in step (1), the amount of the Li-containing compound added is 1%-20% excess by weight, based on satisfying the stoichiometric ratio of the above chemical formula.

[0043] In some embodiments of the present invention, in step (1), the Li-containing compound and the element M-containing compound are... 1 Compounds, compounds containing La, compounds containing element M 2 Compounds, Zr-containing compounds, compounds containing element M 3 The compound and the compound containing element X are respectively nanoscale oxides, hydroxides, nitrates, oxalates, organic alkoxides, or carbonates.

[0044] In some embodiments of the present invention, in step (1), the mixing can be performed using methods, equipment, and processes conventional for material mixing in the art, and this application does not particularly limit them. For example, a sand mill, a ball mill mixing tank, or a planetary mixing tank can be used.

[0045] In some embodiments of the present invention, in step (2), in order to enable the mixture to form a cubic phase better after calcination, and thus obtain a lithium-containing lanthanum zirconium oxide body with high ionic conductivity, the calcination conditions include: the calcination temperature can be 600-1400℃, preferably 800-1200℃; the calcination time can be 2-22h, preferably 6-12h.

[0046] In this invention, the calcination process may include pre-calcination and secondary sintering; wherein, the pre-calcination temperature may be 600-950℃ and the pre-calcination time may be 1-10h; the secondary sintering temperature may be 950-1400℃ and the secondary sintering time may be 1-12h.

[0047] In some embodiments of the present invention, in step (2), the particle size of the lithium lanthanum zirconium oxide body preferably reaches D50 < 20 μm. To achieve this particle size requirement, the sintered product is preferably subjected to crushing treatment. The crushing treatment can be performed using conventional methods, equipment, and processes in the art, for example, an air jet mill can be used.

[0048] In some embodiments of the present invention, in step (3), E can be at least one element selected from Al, Ti, and Zr; G can be at least one element selected from Al, Ti, Zr, and Mg; preferably, E can be at least one element selected from Ti and Zr; G can be at least one element selected from Al, Ti, and Zr.

[0049] In some embodiments of the present invention, in step (3), the amount of the solution or nano-sized sol containing elements E and G fed satisfies the chemical formula Li v E w G h O l In the given condition, 0.5 ≤ v ≤ 10, 0.5 ≤ w ≤ 7, 0.5 ≤ h ≤ 7, and 1 ≤ l ≤ 15; preferably, it satisfies the chemical formula Li. v E w G h O l In the given condition, 1≤v≤8, 1≤w≤5, 1≤h≤5, and 2≤l≤12.

[0050] In some embodiments of the present invention, in step (3), the solution or nano-sol containing elements E and G is an oxide, hydroxide, nitrate, oxalate, organic alkoxide or carbonate containing elements E and G in ethanol, isopropanol or NMP (N-methylpyrrolidone) in a solution or nano-sol.

[0051] In some embodiments of the present invention, in step (3), the weight ratio of the lithium lanthanum zirconium oxide body: solution or nano-sized sol containing elements E and G: solvent can be (5-50):(0.05-2):(10-500).

[0052] In some embodiments of the present invention, in step (3), the solvent may be selected from ethanol, isopropanol or NMP.

[0053] In some embodiments of the present invention, in step (3), the milling process can make elements E and G more uniformly distributed on the surface of the lithium lanthanum zirconium oxide matrix. The milling process can be performed using conventional equipment and processes in the art, and this application does not have any particular limitations on it, as long as the particle size of the milled slurry reaches D50 < 1 μm.

[0054] In some embodiments of the present invention, the drying in step (3) can be carried out using conventional methods in the art. This application does not have any particular limitations on it, as long as the water and solvent in the slurry can be dried and separated.

[0055] In some embodiments of the present invention, in step (4), the heat treatment is preferably carried out by sintering, and the conditions of the heat treatment include: the temperature can be 200-1000℃, preferably 400-800℃; the time can be 2-20h, preferably 6-12h.

[0056] In some embodiments of the present invention, in step (4), the product obtained after the heat treatment is preferably subjected to a crushing process so that the average particle size D50 of the prepared lithium lanthanum zirconium oxide solid electrolyte is 0.1-5 μm. The crushing process can be performed using conventional methods, equipment and processes in the art.

[0057] For the lithium lanthanum zirconium oxide solid electrolyte prepared by the method provided in this invention, the ionic conductivity in its initial state after preparation is compared with the ionic conductivity after being stored under constant temperature and humidity conditions for a certain period of time. The ionic conductivity decreases less and can be well maintained.

[0058] The third aspect of the present invention provides a lithium lanthanum zirconium oxide solid electrolyte prepared by the preparation method described in the second aspect above.

[0059] A fourth aspect of the present invention provides a lithium battery containing the lithium lanthanum zirconium oxide solid electrolyte described in the first or third aspect above.

[0060] A fifth aspect of the present invention provides a battery pack comprising the lithium battery described in the fourth aspect above.

[0061] The present invention will be described in detail below through embodiments. Unless otherwise specified, all materials used in the following embodiments are commercially available products.

[0062] Example 1

[0063] (1) The chemical composition of the prepared matrix satisfies the chemical formula Li 6.98 Ga 0.02 La 2.99 Sr 0.01Zr 1.98 Mg 0.02 O 12 Lithium carbonate, gallium oxide, lanthanum oxide, strontium carbonate, zirconium oxide, and magnesium oxide were weighed and then wet-mixed in a sand mill with alcohol as the mixing medium. The mixing conditions included a sand mill speed of 1000 rpm and a mixing time of 2 hours to obtain a mixture.

[0064] (2) The mixture is calcined in a muffle furnace. The process can be divided into: pre-calcination at 900℃ for 6 hours, followed by heating and secondary sintering at 1100℃ for 10 hours. The product of the secondary sintering is crushed in an air jet mill to make its particle size reach D50 < 4μm, thus obtaining lithium lanthanum zirconium oxide body;

[0065] (3) The ethanol sol containing lithium lanthanum zirconium oxide, titanium dioxide, and zirconium oxide was milled with ethanol in a sand mill to obtain D. 50 A slurry with a diameter of <0.5 μm was prepared and dried in a vacuum oven at 100 °C to obtain an electrolyte precursor. The precursor contained lithium lanthanum zirconium oxide: an ethanol sol of titanium oxide and zirconium oxide (the solid content of the sol was 10 wt%, and the molar ratio of Ti to Zr in the sol was 43:7): ethanol was in a weight ratio of 5:0.05:10.

[0066] (4) The electrolyte precursor was sintered at 600℃ for 8 hours in a dry air atmosphere. The sintered product was then crushed in a high-energy vibration mill to achieve an average particle size D50 of 1 μm, yielding a lithium-lanthanum-zirconium-oxygen solid electrolyte, denoted as P1 (the matrix was tested to be Li). 6.98 Ga 0.02 La 2.99 Sr 0.01 Zr 1.98 Mg 0.02 O 12 The surface coating is: Li4Ti 4.3 Zr 0.7 O 12 ).

[0067] Figure 1 This is a scanning electron microscope (SEM) image of the lithium lanthanum zirconium oxide solid electrolyte prepared in Example 1. Figure 1 As can be seen, after surface coating, there is very little lithium carbonate (the black part shown as number 1 in the figure) on the surface of the lithium lanthanum zirconium oxide solid electrolyte P1.

[0068] Figure 3 This is a high-resolution transmission electron microscope (TEM) image of the lithium lanthanum zirconium oxide solid electrolyte prepared in Example 1. Figure 3 It can be seen that the unit cell of the element-doped lithium lanthanum zirconium oxygen solid electrolyte P1 has a large number of dots with different brightness under high-resolution transmission electron microscopy, indicating that there are lithium ion vacancies in the unit cell.

[0069] Example 2

[0070] (1) The chemical composition of the prepared matrix satisfies the chemical formula Li 6.95 Al 0.05 La 2.99 Y 0.01 Zr 1.99 Sc 0.01 O 12 Weigh out lithium carbonate, aluminum oxide, lanthanum oxide, yttrium oxide, zirconium oxide, and scandium oxide, and wet mix the above raw materials in a sand mill. The mixing medium is alcohol, and the mixing conditions include: the sand mill speed is 1000 rpm, the mixing time is 2 hours, and a mixture is obtained.

[0071] (2) The mixture is calcined in a muffle furnace. The process can be divided into: pre-calcination at 850℃ for 8 hours, followed by heating and secondary sintering at 1200℃ for 8 hours. The product of the secondary sintering is crushed in an air jet mill to make its particle size reach D50 < 4.5 μm, thus obtaining lithium lanthanum zirconium oxide body;

[0072] (3) The isopropanol sol containing lithium lanthanum zirconium oxide, titanium dioxide, and zirconium oxide was milled with isopropanol in a sand mill to obtain D. 50 A slurry with a particle size <0.4 μm was dried in a vacuum oven at 90 °C to obtain an electrolyte precursor. The precursor contained lithium lanthanum zirconium oxide matrix, titanium oxide and zirconium oxide in isopropanol sol (the solid content of the sol was 10 wt%, and the molar ratio of Ti to Zr in the sol was 4:1):isopropanol in a weight ratio of 10:0.2:30.

[0073] (4) The electrolyte precursor was sintered at 750°C for 10 hours in a dry air atmosphere. The sintered product was then crushed in a high-energy vibration mill to achieve an average particle size D50 of 0.8 μm, yielding a lithium-lanthanum-zirconium-oxygen solid electrolyte, denoted as P2 (the matrix was tested to be Li). 6.95 Al 0.05 La 2.99 Y 0.01 Zr 1.99 Sc 0.01 O 12 The surface coating is: Li2Ti 0.8 Zr 0.2 O3).

[0074] Example 3

[0075] (1) The chemical composition of the prepared matrix satisfies the chemical formula Li 6.99 Ge 0.01 La 2.98 Nd 0.02 Zr 1.95Hf 0.05 O 12 Lithium carbonate, germanium oxide, lanthanum oxide, neodymium oxide, zirconium oxide, and hafnium oxide were weighed and wet-mixed in a sand mill with alcohol as the mixing medium. The mixing conditions included a sand mill speed of 1000 rpm and a mixing time of 2 hours to obtain a mixture.

[0076] (2) The mixture is calcined in a muffle furnace. The process can be divided into: pre-calcination at 900℃ for 6 hours, followed by heating and secondary sintering at 1100℃ for 10 hours. The product of the secondary sintering is crushed in an air jet mill to make its particle size reach D50 < 3.5 μm, thus obtaining lithium lanthanum zirconium oxide body;

[0077] (3) The NMP sol containing lithium lanthanum zirconium oxide, alumina, and zirconium oxide was milled with NMP in a sand mill to obtain D. 50 A slurry with a particle size <0.05 μm was dried in a vacuum oven at 130 °C to obtain an electrolyte precursor. The precursor contained lithium lanthanum zirconium oxide matrix, alumina and zirconium oxide NMP sol (the solid content of the sol was 10 wt%, and the molar ratio of Al to Zr in the sol was 1:9):NMP was in a weight ratio of 20:0.5:100.

[0078] (4) The electrolyte precursor was sintered at 650°C for 9 hours in a dry air atmosphere. The sintered product was then crushed in a high-energy vibration mill to achieve an average particle size D50 of 0.1 μm, yielding a lithium-lanthanum-zirconium-oxygen solid electrolyte, denoted as P3 (the matrix was determined to be Li). 6.99 Ge 0.01 La 2.98 Nd 0.02 Zr 1.95 Hf 0.05 O 12 The surface coating is: Li2Zr 0.9 Al 0.1 O3).

[0079] Example 4

[0080] (1) The chemical composition of the prepared matrix satisfies the chemical formula Li 6.92 Ba 0.08 La3Zr 1.5 V 0.5 O 12 Lithium carbonate, barium carbonate, lanthanum oxide, zirconium oxide, and vanadium oxide were weighed and wet-mixed in a sand mill with alcohol as the mixing medium. The mixing conditions included a sand mill speed of 1000 rpm and a mixing time of 2 hours to obtain a mixture.

[0081] (2) The mixture is calcined in a muffle furnace. The process can be divided into: pre-calcination at 700℃ for 4 hours, followed by heating and secondary sintering at 1000℃ for 12 hours. The product of secondary sintering is crushed in an air jet mill to make its particle size reach D50 < 3.5 μm, thus obtaining lithium lanthanum zirconium oxide body;

[0082] (3) An ethanol sol containing lithium lanthanum zirconium oxide, titanium dioxide, and zirconium oxide (the sol has a solid content of 10 wt% and a molar ratio of Ti to Zr of 2:3) is milled with ethanol in a sand mill to obtain D. 50 A slurry with a particle size <0.4 μm was dried in a vacuum oven at 90 °C to obtain an electrolyte precursor. The weight ratio of lithium lanthanum zirconium oxide sol, titanium dioxide and zirconium oxide ethanol sol, to ethanol was 50:2:500.

[0083] (4) The electrolyte precursor was sintered at 750°C for 12 hours in a dry air atmosphere. The sintered product was then crushed in a high-energy vibration mill to achieve an average particle size D50 of 1 μm, yielding a lithium-lanthanum-zirconium-oxygen solid electrolyte, denoted as P4 (the matrix was tested to be Li). 6.92 Ba 0.08 La3Zr 1.5 V 0.5 O 12 The surface coating layer is: Li4Ti2Zr3O 12 ).

[0084] Example 5

[0085] (1) The chemical composition of the prepared matrix satisfies the chemical formula Li 6.95 Fe 0.05 La3Zr2O 12 Lithium carbonate, iron oxide, lanthanum oxide, and zirconium oxide were weighed and then wet-mixed in a sand mill with alcohol as the mixing medium. The mixing conditions included a sand mill speed of 1000 rpm and a mixing time of 2 hours to obtain a mixture.

[0086] (2) The mixture is calcined in a muffle furnace. The process can be divided into: pre-calcination at 850℃ for 6 hours, followed by heating and secondary sintering at 1200℃ for 10 hours. The product of the secondary sintering is crushed in an air jet mill to make its particle size reach D50 < 4.5 μm, thus obtaining lithium lanthanum zirconium oxide body;

[0087] (3) The ethanol sol containing lithium lanthanum zirconium oxide, titanium dioxide, and zirconium oxide was milled with ethanol in a sand mill to obtain D. 50A slurry with a diameter of <0.5 μm was dried in a vacuum oven at 90 °C to obtain an electrolyte precursor. The precursor contained lithium lanthanum zirconium oxide: an ethanol sol of titanium oxide and zirconium oxide (the solid content of the sol was 10 wt%, and the molar ratio of Ti to Zr in the sol was 1:1): ethanol was in a weight ratio of 5:0.1:10.

[0088] (4) The electrolyte precursor was sintered at 700℃ for 15 hours in a dry air atmosphere. The sintered product was then crushed in a high-energy vibration mill to achieve an average particle size D50 of 0.5 μm, yielding a lithium-lanthanum-zirconium-oxygen solid electrolyte, denoted as P5 (the matrix was tested to be Li). 6.95 Fe 0.05 La3Zr2O 12 The surface coating is: Li2Ti 0.5 Zr 0.5 O3).

[0089] Example 6

[0090] (1) The chemical composition of the prepared matrix satisfies the chemical formula Li 6.99 Zn 0.01 La3Zr 1.9 Mn 0.1 O 12 Lithium carbonate, zinc oxide, lanthanum oxide, zirconium oxide, and manganese oxide were weighed and wet-mixed in a sand mill with alcohol as the mixing medium. The mixing conditions included a sand mill speed of 1000 rpm and a mixing time of 2 hours to obtain a mixture.

[0091] (2) The mixture is calcined in a muffle furnace. The process can be divided into: pre-calcination at 750℃ for 5 hours, followed by heating and secondary sintering at 1250℃ for 9 hours. The product of the secondary sintering is crushed in an air jet mill to make its particle size reach D50 < 5μm, thus obtaining lithium lanthanum zirconium oxide body;

[0092] (3) The isopropanol sol containing lithium lanthanum zirconium oxide, alumina, and zirconium oxide was milled with isopropanol in a sand mill to obtain D. 50 A slurry with a particle size <0.8 μm was dried in a vacuum oven at 100 °C to obtain an electrolyte precursor. The precursor contained lithium lanthanum zirconium oxide matrix, alumina and zirconium oxide isopropanol sol (the solid content of the sol was 10 wt%, and the molar ratio of Al to Zr in the sol was 1:9):isopropanol in a weight ratio of 10:0.5:40.

[0093] (4) The electrolyte precursor was sintered at 680℃ for 10 hours in a dry air atmosphere. The sintered product was then crushed in a high-energy vibration mill to achieve an average particle size D50 of 4 μm, yielding a lithium-lanthanum-zirconium-oxygen solid electrolyte, denoted as P6 (the matrix was tested to be Li).6.99 Zn 0.01 La3Zr 1.9 Mn 0.1 O 12 The surface coating is: Li2Zr 0.9 Al 0.1 O3).

[0094] Example 7

[0095] (1) The chemical composition of the prepared matrix satisfies the chemical formula Li 6.95 Ge 0.05 La 2.99 Ac 0.01 Zr 1.98 Co 0.02 O 12 Lithium carbonate, germanium oxide, lanthanum oxide, actinium oxide, zirconium oxide, and cobalt oxide were weighed and wet-mixed in a sand mill with alcohol as the mixing medium. The mixing conditions included a sand mill speed of 1000 rpm and a mixing time of 2 hours to obtain a mixture.

[0096] (2) The mixture is calcined in a muffle furnace. The process can be divided into: pre-calcination at 950℃ for 1 hour, followed by heating and secondary sintering at 950℃ for 12 hours. The product of the secondary sintering is crushed in an air jet mill to make its particle size reach D50 < 5 μm, thus obtaining lithium lanthanum zirconium oxide body;

[0097] (3) The NMP sol containing lithium lanthanum zirconium oxide, titanium dioxide, and zirconium oxide was milled with NMP in a sand mill to obtain D. 50 A slurry with a diameter of <0.6 μm was prepared and dried in a vacuum oven at 135 °C to obtain an electrolyte precursor. The precursor contained lithium lanthanum zirconium oxide: NMP sol of titanium oxide and zirconium oxide (the solid content of the sol was 10 wt%, and the molar ratio of Ti to Zr in the sol was 4:1):NMP was 20:1:100 by weight.

[0098] (4) The electrolyte precursor was sintered at 1000℃ for 2 hours in a dry air atmosphere. The sintered product was then crushed in a high-energy vibration mill to achieve an average particle size D50 of 5 μm, yielding a lithium-lanthanum-zirconium-oxygen solid electrolyte, denoted as P7 (the matrix was tested to be Li). 6.95 Ge 0.05 La 2.99 Ac 0.01 Zr 1.98 Co 0.02 O 12 The surface coating layer is: Li4Ti4ZrO 12 ).

[0099] Example 8

[0100] (1) The chemical composition of the prepared matrix satisfies the chemical formula Li 6.95 Ga 0.05 La 2.99 Rb 0.01 Zr 1.98 Tl 0.02 O 12 Lithium carbonate, gallium oxide, lanthanum oxide, rubidium oxide, zirconium oxide, and thallium oxide were weighed and wet-mixed in a sand mill with alcohol as the mixing medium. The mixing conditions included a sand mill speed of 1000 rpm and a mixing time of 2 hours to obtain a mixture.

[0101] (2) The mixture is calcined in a muffle furnace. The process can be divided into: pre-calcination at 600℃ for 10h, followed by heating and secondary sintering at 1400℃ for 1h. The product of secondary sintering is crushed in an air jet mill to make its particle size reach D50 < 4.5μm, thus obtaining lithium lanthanum zirconium oxide body;

[0102] (3) The ethanol sol containing lithium lanthanum zirconium oxide, titanium dioxide, and zirconium oxide was milled with ethanol in a sand mill to obtain D. 50 A slurry with a particle size <0.3 μm was dried in a vacuum oven at 90 °C to obtain an electrolyte precursor. The precursor contained lithium lanthanum zirconium oxide: ethanol sol of titanium oxide and zirconium oxide (the solid content of the sol was 10 wt%, and the molar ratio of Ti to Zr in the sol was 1:1): ethanol was 50:1:500 by weight.

[0103] (4) The electrolyte precursor was sintered at 200°C for 20 hours in a dry air atmosphere. The sintered product was then crushed in a high-energy vibration mill to achieve an average particle size D50 of 3 μm, yielding a lithium-lanthanum-zirconium-oxygen solid electrolyte, denoted as P8 (the matrix was tested to be Li). 6.95 Ga 0.05 La 2.99 Rb 0.01 Zr 1.98 Tl 0.02 O 12 The surface coating is: Li2Ti 0.5 Zr 0.5 O3).

[0104] Comparative Example 1

[0105] The method of Example 1 was followed, except that in step (3), only the lithium lanthanum zirconium oxide and ethanol were milled in a sand mill (the weight ratio of lithium lanthanum zirconium oxide to ethanol was 5:10), while other conditions were the same as in Example 1. A solid electrolyte was obtained, denoted as DP1 (the chemical formula of which was determined to be Li). 6.98 Ga 0.02 La 2.99Sr 0.01 Zr 1.98 Mg 0.02 O 12 (No surface coating layer).

[0106] Figure 2 This is a scanning electron microscope (SEM) image of the lithium lanthanum zirconium oxide solid electrolyte prepared in Comparative Example 1. Figure 2 As can be seen, the surface of the uncoated lithium lanthanum zirconium oxide solid electrolyte DP1 contains a large amount of black lithium carbonate residue (as shown by label 1 in the figure). The presence of a large amount of lithium carbonate inert layer will severely hinder the transport of lithium ions and reduce the ionic conductivity of the solid electrolyte.

[0107] Comparative Example 2

[0108] The method of Example 1 was followed, except that in step (3), the lithium lanthanum zirconium oxide matrix, the ethanol sol containing silicon oxide, and ethanol were milled in a sand mill (the weight ratio of lithium lanthanum zirconium oxide matrix: ethanol sol containing silicon oxide: ethanol was 5:0.05:10), while other conditions were the same as in Example 1. A solid electrolyte was obtained, denoted as DP2 (the matrix was tested to be Li). 6.98 Ga 0.0 2La 2.99 Sr 0.01 Zr 1.98 Mg 0.02 O 12 The surface coating is Li4SiO4.

[0109] Comparative Example 3

[0110] The method of Example 1 was followed, except that in step (3), the mass ratio of lithium lanthanum zirconium oxide sol, titanium oxide and zirconium oxide ethanol sol, and ethanol was 9:8:100, while other conditions were the same as in Example 1. A solid electrolyte was obtained and denoted as DP3.

[0111] Testing revealed that the matrix of DP3 is Li. 6.98 Ga 0.02 La 2.99 Sr 0.01 Zr 1.98 Mg 0.02 O 12 The surface coating is: Li 11 Ti9Zr8O 35 .

[0112] Comparative Example 4

[0113] The method is the same as in Example 1, except that in step (1), the chemical composition of the prepared matrix satisfies the chemical formula Li. 6.98 Zr 0.02 La 2.99 Sr0.01 Zr 1.98 Mg 0.02 O 12 Lithium carbonate, zirconium oxide, lanthanum oxide, strontium carbonate, zirconium oxide, and magnesium oxide were weighed out, and other conditions were the same as in Example 1. A solid electrolyte, denoted as DP4, was prepared (the matrix was determined to be Li). 6.98 Zr 0.02 La 2.99 Sr 0.01 Zr 1.98 Mg 0.02 O 12 The surface coating is: Li4Ti 4.3 Zr 0.7 O 12 ).

[0114] Comparative Example 5

[0115] The method is the same as in Example 1, except that in step (1), the chemical composition of the prepared matrix satisfies the chemical formula Li6GaLa. 2.99 Sr 0.01 Zr 1.98 Mg 0.02 O 12 Lithium carbonate, gallium oxide, lanthanum oxide, strontium carbonate, zirconium oxide, and magnesium oxide were weighed out, and other conditions were the same as in Example 1. A solid electrolyte, denoted as DP5, was prepared (the matrix was determined to be Li6GaLa). 2.99 Sr 0.01 Zr 1.98 Mg 0.02 O 12 The surface coating is: Li4Ti 4.3 Zr 0.7 O 12 ).

[0116] Test case

[0117] The conductivity of solid electrolytes P1-P8 and DP1-DP4 prepared in Examples 1-8 and Comparative Examples 1-5 of this invention was tested. The ionic conductivity of the above solid electrolytes was tested in their initial state after preparation and after being stored under constant temperature and humidity conditions for 10 days. The specific test process is as follows:

[0118] 1. Conductivity test under initial conditions

[0119] 1) Take 10g of sample from each of P1-P8 and DP1-DP4, place 2g of sample powder into a mold with a diameter of 11mm, and compress it under 100MPa to make a dense disc.

[0120] 2) Place the pressed dense disc in a covered alumina crucible, evenly cover the disc with the remaining 8g of sample powder, close the crucible lid, sinter at 1150℃ for 8 hours, remove the disc and polish it to obtain a solid electrolyte ceramic disc.

[0121] 3) Place the above solid electrolyte ceramic sheet in an electrochemical workstation to test the AC impedance at room temperature (test frequency set to 0.01-10MPa), and calculate the corresponding ionic conductivity according to formula (Ⅰ).

[0122] σ=L / RS (Ⅰ)

[0123] Where σ is the ionic conductivity (S / cm); R is the AC impedance (Ω); L is the thickness of the solid electrolyte ceramic sheet (cm); and S is the area of ​​the solid electrolyte ceramic sheet (cm²). 2 ).

[0124] The test results are shown in Table 1.

[0125] 2. Ionic conductivity test after storage under constant temperature and humidity conditions for 10 days

[0126] 1) Take 10g of each sample from P1-P8 and DP1-DP4 and store them in a constant temperature and humidity test chamber with a relative humidity of 60% and a temperature of 45℃ for 10 days.

[0127] 2) Test the ionic conductivity of the sample after it has been stored for 10 days according to the method and parameters for conductivity testing under the initial state described above.

[0128] The test results are shown in Table 1.

[0129] Table 1

[0130]

[0131]

[0132] As shown in Table 1, regardless of whether they were stored in the initial state or under constant temperature and humidity conditions for 10 days, P1-P8 exhibited higher ionic conductivity, all exceeding that of DP1-DP5. The conductivity of each sample in the initial state was higher than that stored under constant temperature and humidity conditions for 10 days, but the decrease in ionic conductivity for P1-P8 was less pronounced, while the ionic conductivity of DP1-DP5 showed an exponential and significant decrease. Specifically, the surface coatings in DP2 and DP3, and the substrates in DP4 and DP5, did not meet the conditions of this invention, and their ionic conductivity values ​​could not reach the level of P1-P8. DP1, lacking a surface coating, showed the highest decrease in ionic conductivity among all samples after 10 days of storage under constant temperature and humidity conditions.

[0133] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A lithium lanthanum zirconium oxide solid electrolyte, characterized in that, The electrolyte comprises: a matrix and a surface coating layer covering the matrix; The chemical composition of the matrix satisfies the chemical formula Li 7-x M 1 x La 3-y M 2 y Zr 2-z M 3 z O 12-u X u , of which M 1 It is at least one element selected from Ba, Fe, B, Zn, Al, Ga, and Ge; M 2 It is at least one element selected from Rb, Sr, Ca, Y, Bi, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Ac; M 3 X is at least one element selected from Mg, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Se, Tc, Ru, Rh, Pd, Cd, In, Sn, Sb, Te, I, Hf, Ir, Pt, Tl, Pb, Ce, Pu, Np, Ta, Nb, Mo, W; X is at least one element selected from F, Cl, Br, I, S; 0 < x ≤0.05, 0 < y ≤0.03, 0 < z ≤0.3, 0≤ u ≤0.08; The chemical composition of the surface coating layer satisfies the chemical formula Li v E w G h O l Where E is Ti and / or Zr, and G is Al; or, E is Ti, and G is Zr; 0.5 ≤ v ≤10, 0.5≤ w ≤7, 0.5≤ h ≤7, 1≤ l ≤15; The average particle size D of the electrolyte 50 The particle size is 0.1-5 μm; the average particle size of the matrix is ​​<4.5 μm, and the thickness of the surface coating layer is <0.5 μm; The matrix has a garnet-type crystal structure, and high-resolution transmission electron microscopy (HRTEM) analysis revealed the presence of lithium ion vacancies in the unit cells.

2. The electrolyte according to claim 1, wherein, M 1 It is at least one element selected from B, Al, Ga, and Ge; M 2 M is at least one element selected from Sr, Y, Nd, Pm, Sm, Dy, Ho, and Er; 3 X is at least one element selected from Mg, Sc, Ti, Se, Tc, Ru, In, Hf, Ir, Pt, Ta, Nb, Mo, and W; X is at least one element selected from F, Cl, I, and S.

3. The electrolyte according to claim 1 or 2, wherein, 1≤ v ≤8，1≤ w ≤5，1≤ h ≤5，2≤ l ≤12。 4. The electrolyte according to claim 1 or 2, wherein, The weight ratio of the substrate to the surface coating is 100:(0.05-40).

5. A method for preparing a lithium lanthanum zirconium oxide solid electrolyte according to any one of claims 1-4, comprising: (1) Compounds containing Li and compounds containing element M 1 Compounds, compounds containing La, compounds containing element M 2 Compounds, Zr-containing compounds, compounds containing element M 3 Compounds and compounds containing element X are prepared and mixed to obtain a mixture; (2) The mixture is calcined to obtain a lithium lanthanum zirconium oxide body; (3) The lithium-containing lanthanum zirconium oxide, the solution or nano-sized sol containing elements E and G, and the solvent are subjected to sand milling treatment, and then the resulting slurry is dried to obtain the electrolyte precursor; (4) The electrolyte precursor is heat-treated in an oxygen-containing atmosphere to obtain a lithium lanthanum zirconium oxide solid electrolyte; M 1 It is at least one element selected from Ba, Fe, B, Zn, Al, Ga, and Ge; M 2 It is at least one element selected from Rb, Sr, Ca, Y, Bi, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Ac; M 3 X is at least one element selected from Mg, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Se, Tc, Ru, Rh, Pd, Cd, In, Sn, Sb, Te, I, Hf, Ir, Pt, Tl, Pb, Ce, Pu, Np, Ta, Nb, Mo, W; X is at least one element selected from F, Cl, Br, I, S; E is Ti and / or Zr, and G is Al; or, E is Ti and G is Zr; The amount of solution or nano-sized sol containing elements E and G should meet the requirements of the chemical formula Li v E w G h O l In the range 0.5≤v≤10, 0.5≤w≤7, 0.5≤h≤7, 1≤l≤15; Li-containing compounds, M-containing compounds 1 Compounds, compounds containing La, compounds containing element M 2 Compounds, Zr-containing compounds, compounds containing element M 3 The amount of compound and compound containing element X fed in the feed must satisfy the chemical formula Li 7-x M 1 x La 3-y M 2 y Zr 2-z M 3 z O 12-u X u 0 < x ≤0.05, 0 < y ≤0.03, 0≤ z ≤0.3, 0≤ u ≤0.

08.

6. The preparation method according to claim 5, wherein, M 1 It is at least one element selected from B, Al, Ga, and Ge; M 2 M is at least one element selected from Sr, Y, Nd, Pm, Sm, Dy, Ho, and Er; 3 X is at least one element selected from Mg, Sc, Ti, Se, Tc, Ru, In, Hf, Ir, Pt, Ta, Nb, Mo, and W; X is at least one element selected from F, Cl, I, and S.

7. The preparation method according to claim 5, wherein, The weight ratio of the lithium-containing lanthanum zirconium oxide: solution or nanoscale sol containing elements E and G: solvent is (5-50):(0.05-2):(10-500).

8. The preparation method according to claim 5, wherein, Li-containing compounds, M-containing compounds 1 Compounds, compounds containing La, compounds containing element M 2 Compounds, Zr-containing compounds, compounds containing element M 3 The compound and the compound containing element X are respectively nanoscale oxides, hydroxides, nitrates, oxalates, organic alkoxides, or carbonates.

9. The preparation method according to claim 5, wherein, The solution or nano-sol containing elements E and G is a solution or nano-sol of oxides, hydroxides, nitrates, oxalates, organic alkoxides or carbonates containing elements E and G in ethanol, isopropanol or NMP.

10. The preparation method according to claim 5, wherein, The solvent is selected from ethanol, isopropanol, or NMP.

11. The preparation method according to claim 5, wherein, The roasting temperature is 600-1400℃; the roasting time is 2-22h. And / or, the heat treatment temperature is 200-1000℃; the heat treatment time is 2-20h.

12. The preparation method according to claim 11, wherein, The roasting temperature is 800-1200℃; the roasting time is 6-12 hours. And / or, the heat treatment temperature is 400-800℃; the heat treatment time is 6-12h.

13. The preparation method according to claim 5, wherein, The calcination process includes pre-calcination and secondary sintering; wherein the pre-calcination temperature is 600-950℃ and the pre-calcination time is 1-10h; the secondary sintering temperature is 950-1400℃ and the secondary sintering time is 1-12h.

14. A lithium lanthanum zirconium oxide solid electrolyte prepared by any one of claims 5-13.

15. A lithium battery comprising the lithium lanthanum zirconium oxide solid electrolyte according to any one of claims 1-4 and 14.

16. A battery pack comprising the lithium battery of claim 15.

Images